diff --git a/Directory.Build.props b/Directory.Build.props
index 6ad5e13a1..26d84ac53 100644
--- a/Directory.Build.props
+++ b/Directory.Build.props
@@ -49,7 +49,7 @@
     <!-- hard binding to net8, no property and env variable allowed-->
     <TargetFrameworks>net8.0</TargetFrameworks>
   </PropertyGroup>
-  
+
   <!-- Debug-NET7, Release-NET7 are mostly for development convenience -->
   <PropertyGroup Condition = "$(Configuration.Contains('NET7')) == 'true'">
     <!-- hard binding to net7, no property and env variable allowed-->
@@ -127,6 +127,14 @@
     <ContinuousIntegrationBuild>true</ContinuousIntegrationBuild>
   </PropertyGroup>
 
+  <ItemGroup>
+    <Using Include="System" />
+    <Using Include="System.Collections.Generic" />
+    <Using Include="System.Linq" />
+    <Using Include="System.Threading" />
+    <Using Include="System.Threading.Tasks" />
+  </ItemGroup>
+
   <ItemGroup>
     <SourceRoot Include="$(SolutionDir)"/>
     <PackageReference Condition="$(DoGeneratePackage) == 'true'"
diff --git a/Extensions/TestCommon/AssemblyExtensions.cs b/Extensions/TestCommon/AssemblyExtensions.cs
index ad71969fd..87d1f20f4 100644
--- a/Extensions/TestCommon/AssemblyExtensions.cs
+++ b/Extensions/TestCommon/AssemblyExtensions.cs
@@ -1,6 +1,4 @@
-using System;
 using System.Reflection;
-using System.Collections.Generic;
 using System.Text;
 using System.Configuration;
 
diff --git a/Extensions/TestCommon/Model/Bar.cs b/Extensions/TestCommon/Model/Bar.cs
index b6e04e1f4..41514c963 100644
--- a/Extensions/TestCommon/Model/Bar.cs
+++ b/Extensions/TestCommon/Model/Bar.cs
@@ -1,4 +1,3 @@
-using System;
 using Xtensive.Orm;
 
 namespace TestCommon.Model
diff --git a/Extensions/TestCommon/Model/Bar2.cs b/Extensions/TestCommon/Model/Bar2.cs
index 48c315214..1f07dedd1 100644
--- a/Extensions/TestCommon/Model/Bar2.cs
+++ b/Extensions/TestCommon/Model/Bar2.cs
@@ -1,4 +1,3 @@
-using System;
 using Xtensive.Orm;
 
 namespace TestCommon.Model
diff --git a/Extensions/TestCommon/Model/LinqCompilerContainer.cs b/Extensions/TestCommon/Model/LinqCompilerContainer.cs
index 5f52b18ee..d4ddd85fd 100644
--- a/Extensions/TestCommon/Model/LinqCompilerContainer.cs
+++ b/Extensions/TestCommon/Model/LinqCompilerContainer.cs
@@ -1,4 +1,3 @@
-using System;
 using System.Linq.Expressions;
 using Xtensive.Core;
 using Xtensive.Linq;
diff --git a/Extensions/TestCommon/Tests/TestConfigurationTest.cs b/Extensions/TestCommon/Tests/TestConfigurationTest.cs
index d6eb9f01f..f0d1e1ff8 100644
--- a/Extensions/TestCommon/Tests/TestConfigurationTest.cs
+++ b/Extensions/TestCommon/Tests/TestConfigurationTest.cs
@@ -1,4 +1,3 @@
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Tests;
 
diff --git a/Extensions/Xtensive.Orm.BulkOperations.Tests/ContainsTest.cs b/Extensions/Xtensive.Orm.BulkOperations.Tests/ContainsTest.cs
index 846f628e5..0144a5b6f 100644
--- a/Extensions/Xtensive.Orm.BulkOperations.Tests/ContainsTest.cs
+++ b/Extensions/Xtensive.Orm.BulkOperations.Tests/ContainsTest.cs
@@ -2,8 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.BulkOperations.ContainsTestModel;
 using Xtensive.Orm.Configuration;
diff --git a/Extensions/Xtensive.Orm.BulkOperations.Tests/Extensions.cs b/Extensions/Xtensive.Orm.BulkOperations.Tests/Extensions.cs
index 12e034678..ac628a584 100644
--- a/Extensions/Xtensive.Orm.BulkOperations.Tests/Extensions.cs
+++ b/Extensions/Xtensive.Orm.BulkOperations.Tests/Extensions.cs
@@ -1,4 +1,3 @@
-using System;
 using NUnit.Framework;
 using NUnit.Framework.Constraints;
 
diff --git a/Extensions/Xtensive.Orm.BulkOperations.Tests/Issues/IssueJira0560_ChangeFieldWhichDefinedInAncestorClassBug.cs b/Extensions/Xtensive.Orm.BulkOperations.Tests/Issues/IssueJira0560_ChangeFieldWhichDefinedInAncestorClassBug.cs
index 62deb808a..ccf5ed8ba 100644
--- a/Extensions/Xtensive.Orm.BulkOperations.Tests/Issues/IssueJira0560_ChangeFieldWhichDefinedInAncestorClassBug.cs
+++ b/Extensions/Xtensive.Orm.BulkOperations.Tests/Issues/IssueJira0560_ChangeFieldWhichDefinedInAncestorClassBug.cs
@@ -4,9 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2014.10.16
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Text;
 using NUnit.Framework;
 using Xtensive.Orm.Model;
diff --git a/Extensions/Xtensive.Orm.BulkOperations.Tests/Issues/IssueJira0565_IgnoringTakeMethodOnTranslation.cs b/Extensions/Xtensive.Orm.BulkOperations.Tests/Issues/IssueJira0565_IgnoringTakeMethodOnTranslation.cs
index eb4e745c3..552dc6165 100644
--- a/Extensions/Xtensive.Orm.BulkOperations.Tests/Issues/IssueJira0565_IgnoringTakeMethodOnTranslation.cs
+++ b/Extensions/Xtensive.Orm.BulkOperations.Tests/Issues/IssueJira0565_IgnoringTakeMethodOnTranslation.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2015.02.06
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using TestCommon.Model;
 using Xtensive.Orm.Providers;
diff --git a/Extensions/Xtensive.Orm.BulkOperations.Tests/Issues/JoinedTableAsSourceForDelete.cs b/Extensions/Xtensive.Orm.BulkOperations.Tests/Issues/JoinedTableAsSourceForDelete.cs
index 20218136e..684ed8137 100644
--- a/Extensions/Xtensive.Orm.BulkOperations.Tests/Issues/JoinedTableAsSourceForDelete.cs
+++ b/Extensions/Xtensive.Orm.BulkOperations.Tests/Issues/JoinedTableAsSourceForDelete.cs
@@ -1,4 +1,3 @@
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.BulkOperations.Tests.Issues.WrongAliassesIssue;
 
diff --git a/Extensions/Xtensive.Orm.BulkOperations.Tests/Other.cs b/Extensions/Xtensive.Orm.BulkOperations.Tests/Other.cs
index 1079e6526..c5095c1d5 100644
--- a/Extensions/Xtensive.Orm.BulkOperations.Tests/Other.cs
+++ b/Extensions/Xtensive.Orm.BulkOperations.Tests/Other.cs
@@ -4,10 +4,6 @@
 // Created by: Alexander Ovchinnikov
 // Created:    2012.02.29
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Threading.Tasks;
 using NUnit.Framework;
 using TestCommon.Model;
 
diff --git a/Extensions/Xtensive.Orm.BulkOperations.Tests/ReferenceFields.cs b/Extensions/Xtensive.Orm.BulkOperations.Tests/ReferenceFields.cs
index 9e8d74df7..c0357561f 100644
--- a/Extensions/Xtensive.Orm.BulkOperations.Tests/ReferenceFields.cs
+++ b/Extensions/Xtensive.Orm.BulkOperations.Tests/ReferenceFields.cs
@@ -1,5 +1,3 @@
-using System;
-using System.Linq;
 using NUnit.Framework;
 using TestCommon.Model;
 
diff --git a/Extensions/Xtensive.Orm.BulkOperations.Tests/Structures.cs b/Extensions/Xtensive.Orm.BulkOperations.Tests/Structures.cs
index 59aacb1b5..9ec7e15cc 100644
--- a/Extensions/Xtensive.Orm.BulkOperations.Tests/Structures.cs
+++ b/Extensions/Xtensive.Orm.BulkOperations.Tests/Structures.cs
@@ -1,4 +1,3 @@
-using System.Linq;
 using NUnit.Framework;
 using TestCommon.Model;
 
diff --git a/Extensions/Xtensive.Orm.BulkOperations/BulkExtensions.cs b/Extensions/Xtensive.Orm.BulkOperations/BulkExtensions.cs
index 599412cd3..8bc74c63f 100644
--- a/Extensions/Xtensive.Orm.BulkOperations/BulkExtensions.cs
+++ b/Extensions/Xtensive.Orm.BulkOperations/BulkExtensions.cs
@@ -2,12 +2,8 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
 using System.Diagnostics.Contracts;
-using System.Linq;
 using System.Linq.Expressions;
-using System.Threading;
-using System.Threading.Tasks;
 
 namespace Xtensive.Orm.BulkOperations
 {
diff --git a/Extensions/Xtensive.Orm.BulkOperations/Internals/AddValueContext.cs b/Extensions/Xtensive.Orm.BulkOperations/Internals/AddValueContext.cs
index a31faed2e..e08d356fa 100644
--- a/Extensions/Xtensive.Orm.BulkOperations/Internals/AddValueContext.cs
+++ b/Extensions/Xtensive.Orm.BulkOperations/Internals/AddValueContext.cs
@@ -1,4 +1,3 @@
-using System.Collections.Generic;
 using System.Linq.Expressions;
 using Xtensive.Linq;
 using Xtensive.Orm.Model;
diff --git a/Extensions/Xtensive.Orm.BulkOperations/Internals/BaseSqlVisitor.cs b/Extensions/Xtensive.Orm.BulkOperations/Internals/BaseSqlVisitor.cs
index 48563d6d8..f41ca38eb 100644
--- a/Extensions/Xtensive.Orm.BulkOperations/Internals/BaseSqlVisitor.cs
+++ b/Extensions/Xtensive.Orm.BulkOperations/Internals/BaseSqlVisitor.cs
@@ -1,5 +1,3 @@
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Sql;
 using Xtensive.Sql.Ddl;
 using Xtensive.Sql.Dml;
diff --git a/Extensions/Xtensive.Orm.BulkOperations/Internals/BulkDeleteOperation.cs b/Extensions/Xtensive.Orm.BulkOperations/Internals/BulkDeleteOperation.cs
index e41f13cea..7f91c51b5 100644
--- a/Extensions/Xtensive.Orm.BulkOperations/Internals/BulkDeleteOperation.cs
+++ b/Extensions/Xtensive.Orm.BulkOperations/Internals/BulkDeleteOperation.cs
@@ -2,10 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Linq;
-using System.Threading;
-using System.Threading.Tasks;
 using Xtensive.Orm.Linq;
 using Xtensive.Orm.Providers;
 using Xtensive.Orm.Services;
diff --git a/Extensions/Xtensive.Orm.BulkOperations/Internals/BulkUpdateOperation.cs b/Extensions/Xtensive.Orm.BulkOperations/Internals/BulkUpdateOperation.cs
index e2cc668a0..0d5372311 100644
--- a/Extensions/Xtensive.Orm.BulkOperations/Internals/BulkUpdateOperation.cs
+++ b/Extensions/Xtensive.Orm.BulkOperations/Internals/BulkUpdateOperation.cs
@@ -2,13 +2,8 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Linq.Expressions;
 using System.Reflection;
-using System.Threading;
-using System.Threading.Tasks;
 using Xtensive.Orm.Linq;
 using Xtensive.Orm.Providers;
 using Xtensive.Orm.Services;
diff --git a/Extensions/Xtensive.Orm.BulkOperations/Internals/ExpressionExtensions.cs b/Extensions/Xtensive.Orm.BulkOperations/Internals/ExpressionExtensions.cs
index ad73adf95..eb83b5199 100644
--- a/Extensions/Xtensive.Orm.BulkOperations/Internals/ExpressionExtensions.cs
+++ b/Extensions/Xtensive.Orm.BulkOperations/Internals/ExpressionExtensions.cs
@@ -2,8 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Linq;
 using System.Linq.Expressions;
 using Xtensive.Linq;
 using Xtensive.Reflection;
diff --git a/Extensions/Xtensive.Orm.BulkOperations/Internals/ExpressionVisitor.cs b/Extensions/Xtensive.Orm.BulkOperations/Internals/ExpressionVisitor.cs
index 273febeff..5f4439fec 100644
--- a/Extensions/Xtensive.Orm.BulkOperations/Internals/ExpressionVisitor.cs
+++ b/Extensions/Xtensive.Orm.BulkOperations/Internals/ExpressionVisitor.cs
@@ -2,8 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Collections.Generic;
 using System.Collections.ObjectModel;
 using System.Linq.Expressions;
 using Xtensive.Core;
diff --git a/Extensions/Xtensive.Orm.BulkOperations/Internals/InsertOperation.cs b/Extensions/Xtensive.Orm.BulkOperations/Internals/InsertOperation.cs
index e48f5da53..b574d7a05 100644
--- a/Extensions/Xtensive.Orm.BulkOperations/Internals/InsertOperation.cs
+++ b/Extensions/Xtensive.Orm.BulkOperations/Internals/InsertOperation.cs
@@ -2,12 +2,7 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Linq.Expressions;
-using System.Threading;
-using System.Threading.Tasks;
 using Xtensive.Orm.Linq;
 using Xtensive.Orm.Services;
 using Xtensive.Sql;
diff --git a/Extensions/Xtensive.Orm.BulkOperations/Internals/Operation.cs b/Extensions/Xtensive.Orm.BulkOperations/Internals/Operation.cs
index 168ed0d64..23e8d3664 100644
--- a/Extensions/Xtensive.Orm.BulkOperations/Internals/Operation.cs
+++ b/Extensions/Xtensive.Orm.BulkOperations/Internals/Operation.cs
@@ -2,11 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Threading;
-using System.Threading.Tasks;
 using Xtensive.Core;
 using Xtensive.Orm.Linq;
 using Xtensive.Orm.Providers;
diff --git a/Extensions/Xtensive.Orm.BulkOperations/Internals/QueryOperation.cs b/Extensions/Xtensive.Orm.BulkOperations/Internals/QueryOperation.cs
index b295a1751..147f79664 100644
--- a/Extensions/Xtensive.Orm.BulkOperations/Internals/QueryOperation.cs
+++ b/Extensions/Xtensive.Orm.BulkOperations/Internals/QueryOperation.cs
@@ -2,9 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Linq.Expressions;
 using Xtensive.Core;
 using Xtensive.Orm.Linq;
diff --git a/Extensions/Xtensive.Orm.BulkOperations/Internals/SetOperation.cs b/Extensions/Xtensive.Orm.BulkOperations/Internals/SetOperation.cs
index 806a6dcb7..6492d076a 100644
--- a/Extensions/Xtensive.Orm.BulkOperations/Internals/SetOperation.cs
+++ b/Extensions/Xtensive.Orm.BulkOperations/Internals/SetOperation.cs
@@ -2,9 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Linq.Expressions;
 using Xtensive.Orm.Model;
 using Xtensive.Orm.Services;
diff --git a/Extensions/Xtensive.Orm.BulkOperations/Internals/SetStatement.cs b/Extensions/Xtensive.Orm.BulkOperations/Internals/SetStatement.cs
index e53a7fd12..62935a9e2 100644
--- a/Extensions/Xtensive.Orm.BulkOperations/Internals/SetStatement.cs
+++ b/Extensions/Xtensive.Orm.BulkOperations/Internals/SetStatement.cs
@@ -1,5 +1,3 @@
-using System;
-using System.Collections.Generic;
 using Xtensive.Sql;
 using Xtensive.Sql.Dml;
 
diff --git a/Extensions/Xtensive.Orm.BulkOperations/Internals/Updatable.cs b/Extensions/Xtensive.Orm.BulkOperations/Internals/Updatable.cs
index 9b417bb18..56a7063f5 100644
--- a/Extensions/Xtensive.Orm.BulkOperations/Internals/Updatable.cs
+++ b/Extensions/Xtensive.Orm.BulkOperations/Internals/Updatable.cs
@@ -1,6 +1,3 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Linq.Expressions;
 
 namespace Xtensive.Orm.BulkOperations
diff --git a/Extensions/Xtensive.Orm.BulkOperations/Internals/WellKnownMembers.cs b/Extensions/Xtensive.Orm.BulkOperations/Internals/WellKnownMembers.cs
index 67dc690d4..740fde85a 100644
--- a/Extensions/Xtensive.Orm.BulkOperations/Internals/WellKnownMembers.cs
+++ b/Extensions/Xtensive.Orm.BulkOperations/Internals/WellKnownMembers.cs
@@ -2,8 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Linq;
 using System.Reflection;
 using Xtensive.Orm.Services;
 
diff --git a/Extensions/Xtensive.Orm.Localization.Tests/AccessToLocalizationOnUpgrade.cs b/Extensions/Xtensive.Orm.Localization.Tests/AccessToLocalizationOnUpgrade.cs
index 708d7d83f..59d589074 100644
--- a/Extensions/Xtensive.Orm.Localization.Tests/AccessToLocalizationOnUpgrade.cs
+++ b/Extensions/Xtensive.Orm.Localization.Tests/AccessToLocalizationOnUpgrade.cs
@@ -1,5 +1,4 @@
 using System.Globalization;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Localization.Tests.Model;
 using Xtensive.Orm.Upgrade;
diff --git a/Extensions/Xtensive.Orm.Localization.Tests/CurrentThreadTest.cs b/Extensions/Xtensive.Orm.Localization.Tests/CurrentThreadTest.cs
index 40ceb291d..5f927103a 100644
--- a/Extensions/Xtensive.Orm.Localization.Tests/CurrentThreadTest.cs
+++ b/Extensions/Xtensive.Orm.Localization.Tests/CurrentThreadTest.cs
@@ -1,5 +1,3 @@
-using System.Linq;
-using System.Threading;
 using NUnit.Framework;
 using Xtensive.Orm.Localization.Tests.Model;
 
diff --git a/Extensions/Xtensive.Orm.Localization.Tests/DirectEditTest.cs b/Extensions/Xtensive.Orm.Localization.Tests/DirectEditTest.cs
index a3a441584..ab4298eb2 100644
--- a/Extensions/Xtensive.Orm.Localization.Tests/DirectEditTest.cs
+++ b/Extensions/Xtensive.Orm.Localization.Tests/DirectEditTest.cs
@@ -1,4 +1,3 @@
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Localization.Tests.Model;
 
diff --git a/Extensions/Xtensive.Orm.Localization.Tests/LocalizationScopeTest.cs b/Extensions/Xtensive.Orm.Localization.Tests/LocalizationScopeTest.cs
index de7d6793e..fcb3b5088 100644
--- a/Extensions/Xtensive.Orm.Localization.Tests/LocalizationScopeTest.cs
+++ b/Extensions/Xtensive.Orm.Localization.Tests/LocalizationScopeTest.cs
@@ -1,4 +1,3 @@
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Localization.Tests.Model;
 
diff --git a/Extensions/Xtensive.Orm.Localization.Tests/Model/Page.cs b/Extensions/Xtensive.Orm.Localization.Tests/Model/Page.cs
index b6c774f60..7e51e7e8a 100644
--- a/Extensions/Xtensive.Orm.Localization.Tests/Model/Page.cs
+++ b/Extensions/Xtensive.Orm.Localization.Tests/Model/Page.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2009.11.27
 
-using System;
 using Xtensive.Orm;
 
 namespace Xtensive.Orm.Localization.Tests.Model
diff --git a/Extensions/Xtensive.Orm.Localization.Tests/Model/PageLocalization.cs b/Extensions/Xtensive.Orm.Localization.Tests/Model/PageLocalization.cs
index a4c51e3c1..0d5d58a60 100644
--- a/Extensions/Xtensive.Orm.Localization.Tests/Model/PageLocalization.cs
+++ b/Extensions/Xtensive.Orm.Localization.Tests/Model/PageLocalization.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2009.11.27
 
-using System;
 using System.Globalization;
 using Xtensive.Orm;
 
diff --git a/Extensions/Xtensive.Orm.Localization.Tests/MultipleNodesTest.cs b/Extensions/Xtensive.Orm.Localization.Tests/MultipleNodesTest.cs
index a5096e4b2..cf36f5318 100644
--- a/Extensions/Xtensive.Orm.Localization.Tests/MultipleNodesTest.cs
+++ b/Extensions/Xtensive.Orm.Localization.Tests/MultipleNodesTest.cs
@@ -5,7 +5,6 @@
 // Created:    2019.12.04
 
 using NUnit.Framework;
-using System.Collections.Generic;
 using System.Globalization;
 using TestCommon;
 using Xtensive.Orm.Configuration;
diff --git a/Extensions/Xtensive.Orm.Localization.Tests/ProjectionToCustomTypesTests.cs b/Extensions/Xtensive.Orm.Localization.Tests/ProjectionToCustomTypesTests.cs
index c4f94113d..d8ef3655c 100644
--- a/Extensions/Xtensive.Orm.Localization.Tests/ProjectionToCustomTypesTests.cs
+++ b/Extensions/Xtensive.Orm.Localization.Tests/ProjectionToCustomTypesTests.cs
@@ -2,8 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System.Linq;
-using System.Threading;
 using NUnit.Framework;
 using Xtensive.Orm.Localization.Tests.Model;
 
diff --git a/Extensions/Xtensive.Orm.Localization.Tests/QueryTests.cs b/Extensions/Xtensive.Orm.Localization.Tests/QueryTests.cs
index e298ff92a..7f1940b4c 100644
--- a/Extensions/Xtensive.Orm.Localization.Tests/QueryTests.cs
+++ b/Extensions/Xtensive.Orm.Localization.Tests/QueryTests.cs
@@ -1,6 +1,3 @@
-using System;
-using System.Linq;
-using System.Threading;
 using NUnit.Framework;
 using Xtensive.Orm.Localization.Tests.Model;
 
diff --git a/Extensions/Xtensive.Orm.Localization/Configuration/Elements/ConfigurationSection.cs b/Extensions/Xtensive.Orm.Localization/Configuration/Elements/ConfigurationSection.cs
index c13ec9171..4ca10b7ea 100644
--- a/Extensions/Xtensive.Orm.Localization/Configuration/Elements/ConfigurationSection.cs
+++ b/Extensions/Xtensive.Orm.Localization/Configuration/Elements/ConfigurationSection.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2012.07.06
 
-using System;
 using System.Configuration;
 
 namespace Xtensive.Orm.Localization.Configuration
diff --git a/Extensions/Xtensive.Orm.Localization/Configuration/LocalizationConfiguration.cs b/Extensions/Xtensive.Orm.Localization/Configuration/LocalizationConfiguration.cs
index aab701d99..97d7868e0 100644
--- a/Extensions/Xtensive.Orm.Localization/Configuration/LocalizationConfiguration.cs
+++ b/Extensions/Xtensive.Orm.Localization/Configuration/LocalizationConfiguration.cs
@@ -4,10 +4,8 @@
 // Created by: Dmitri Maximov
 // Created:    2012.07.06
 
-using System;
 using System.Configuration;
 using System.Globalization;
-using System.Threading;
 
 namespace Xtensive.Orm.Localization.Configuration
 {
diff --git a/Extensions/Xtensive.Orm.Localization/Internals/LocalizationExpressionBuilder.cs b/Extensions/Xtensive.Orm.Localization/Internals/LocalizationExpressionBuilder.cs
index 5602eb490..4644a236d 100644
--- a/Extensions/Xtensive.Orm.Localization/Internals/LocalizationExpressionBuilder.cs
+++ b/Extensions/Xtensive.Orm.Localization/Internals/LocalizationExpressionBuilder.cs
@@ -4,8 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2009.12.28
 
-using System;
-using System.Linq;
 using System.Linq.Expressions;
 using System.Reflection;
 
diff --git a/Extensions/Xtensive.Orm.Localization/Internals/TypeLocalizationInfo.cs b/Extensions/Xtensive.Orm.Localization/Internals/TypeLocalizationInfo.cs
index 2b57991ce..d2fa799cb 100644
--- a/Extensions/Xtensive.Orm.Localization/Internals/TypeLocalizationInfo.cs
+++ b/Extensions/Xtensive.Orm.Localization/Internals/TypeLocalizationInfo.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2009.12.28
 
-using System;
 using System.Reflection;
 using Xtensive.Orm.Model;
 using TypeInfo = Xtensive.Orm.Model.TypeInfo;
diff --git a/Extensions/Xtensive.Orm.Localization/Internals/TypeLocalizationMap.cs b/Extensions/Xtensive.Orm.Localization/Internals/TypeLocalizationMap.cs
index 51e17ff14..14a1ac13f 100644
--- a/Extensions/Xtensive.Orm.Localization/Internals/TypeLocalizationMap.cs
+++ b/Extensions/Xtensive.Orm.Localization/Internals/TypeLocalizationMap.cs
@@ -4,8 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2009.12.28
 
-using System;
-using System.Collections.Generic;
 using Xtensive.Orm.Localization.Configuration;
 using Xtensive.Orm.Model;
 using Xtensive.Orm;
diff --git a/Extensions/Xtensive.Orm.Localization/Localization.cs b/Extensions/Xtensive.Orm.Localization/Localization.cs
index 8fdbc9757..c97825701 100644
--- a/Extensions/Xtensive.Orm.Localization/Localization.cs
+++ b/Extensions/Xtensive.Orm.Localization/Localization.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2009.11.27
 
-using System;
 using System.Globalization;
 
 namespace Xtensive.Orm.Localization
diff --git a/Extensions/Xtensive.Orm.Localization/LocalizationContext.cs b/Extensions/Xtensive.Orm.Localization/LocalizationContext.cs
index 6944a8b21..285adb86a 100644
--- a/Extensions/Xtensive.Orm.Localization/LocalizationContext.cs
+++ b/Extensions/Xtensive.Orm.Localization/LocalizationContext.cs
@@ -4,9 +4,7 @@
 // Created by: Dmitri Maximov
 // Created:    2009.11.30
 
-using System;
 using System.Globalization;
-using System.Threading;
 using Xtensive.Core;
 
 namespace Xtensive.Orm.Localization
diff --git a/Extensions/Xtensive.Orm.Localization/LocalizationPolicy.cs b/Extensions/Xtensive.Orm.Localization/LocalizationPolicy.cs
index e56f46984..b5b3c2161 100644
--- a/Extensions/Xtensive.Orm.Localization/LocalizationPolicy.cs
+++ b/Extensions/Xtensive.Orm.Localization/LocalizationPolicy.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2009.11.30
 
-using System;
 
 namespace Xtensive.Orm.Localization
 {
diff --git a/Extensions/Xtensive.Orm.Localization/LocalizationSet.cs b/Extensions/Xtensive.Orm.Localization/LocalizationSet.cs
index d2ec63120..a5931f2bf 100644
--- a/Extensions/Xtensive.Orm.Localization/LocalizationSet.cs
+++ b/Extensions/Xtensive.Orm.Localization/LocalizationSet.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2009.11.30
 
-using System;
 using System.Globalization;
 using Xtensive.Orm.Model;
 
diff --git a/Extensions/Xtensive.Orm.Localization/QueryExtensions.cs b/Extensions/Xtensive.Orm.Localization/QueryExtensions.cs
index f76b33bcd..fd63fc82c 100644
--- a/Extensions/Xtensive.Orm.Localization/QueryExtensions.cs
+++ b/Extensions/Xtensive.Orm.Localization/QueryExtensions.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2009.12.16
 
-using System.Linq;
 using Xtensive.Orm;
 
 namespace Xtensive.Orm.Localization
diff --git a/Extensions/Xtensive.Orm.Reprocessing.Tests/Tests/Context.cs b/Extensions/Xtensive.Orm.Reprocessing.Tests/Tests/Context.cs
index 207d16cbf..8b8d4b0ea 100644
--- a/Extensions/Xtensive.Orm.Reprocessing.Tests/Tests/Context.cs
+++ b/Extensions/Xtensive.Orm.Reprocessing.Tests/Tests/Context.cs
@@ -2,10 +2,6 @@
 // ReSharper disable ReturnValueOfPureMethodIsNotUsed
 // ReSharper disable AccessToModifiedClosure
 
-using System;
-using System.Linq;
-using System.Threading;
-using System.Threading.Tasks;
 using System.Transactions;
 using NUnit.Framework;
 using TestCommon.Model;
diff --git a/Extensions/Xtensive.Orm.Reprocessing.Tests/Tests/DeadlockReprocessing.cs b/Extensions/Xtensive.Orm.Reprocessing.Tests/Tests/DeadlockReprocessing.cs
index f0f186c87..32d99a3fd 100644
--- a/Extensions/Xtensive.Orm.Reprocessing.Tests/Tests/DeadlockReprocessing.cs
+++ b/Extensions/Xtensive.Orm.Reprocessing.Tests/Tests/DeadlockReprocessing.cs
@@ -2,10 +2,6 @@
 // ReSharper disable ReturnValueOfPureMethodIsNotUsed
 // ReSharper disable AccessToModifiedClosure
 
-using System;
-using System.Linq;
-using System.Threading;
-using System.Threading.Tasks;
 using System.Transactions;
 using NUnit.Framework;
 using TestCommon.Model;
diff --git a/Extensions/Xtensive.Orm.Reprocessing.Tests/Tests/Other.cs b/Extensions/Xtensive.Orm.Reprocessing.Tests/Tests/Other.cs
index 79dfb0e75..0e5cc359d 100644
--- a/Extensions/Xtensive.Orm.Reprocessing.Tests/Tests/Other.cs
+++ b/Extensions/Xtensive.Orm.Reprocessing.Tests/Tests/Other.cs
@@ -1,4 +1,3 @@
-using System.Linq;
 using System.Transactions;
 using NUnit.Framework;
 using TestCommon.Model;
diff --git a/Extensions/Xtensive.Orm.Reprocessing.Tests/Tests/UniqueConstraintViolationReprocessing.cs b/Extensions/Xtensive.Orm.Reprocessing.Tests/Tests/UniqueConstraintViolationReprocessing.cs
index c901fa181..2c7f581c4 100644
--- a/Extensions/Xtensive.Orm.Reprocessing.Tests/Tests/UniqueConstraintViolationReprocessing.cs
+++ b/Extensions/Xtensive.Orm.Reprocessing.Tests/Tests/UniqueConstraintViolationReprocessing.cs
@@ -2,8 +2,6 @@
 // ReSharper disable ReturnValueOfPureMethodIsNotUsed
 // ReSharper disable AccessToModifiedClosure
 
-using System;
-using System.Threading;
 using System.Transactions;
 using NUnit.Framework;
 using TestCommon.Model;
diff --git a/Extensions/Xtensive.Orm.Reprocessing/Configuration/ConfigurationSection.cs b/Extensions/Xtensive.Orm.Reprocessing/Configuration/ConfigurationSection.cs
index d93d13802..23830ebcb 100644
--- a/Extensions/Xtensive.Orm.Reprocessing/Configuration/ConfigurationSection.cs
+++ b/Extensions/Xtensive.Orm.Reprocessing/Configuration/ConfigurationSection.cs
@@ -1,4 +1,3 @@
-using System;
 using System.ComponentModel;
 using System.Configuration;
 
diff --git a/Extensions/Xtensive.Orm.Reprocessing/Configuration/ReprocessingConfiguration.cs b/Extensions/Xtensive.Orm.Reprocessing/Configuration/ReprocessingConfiguration.cs
index 12b6ec561..7e536b29e 100644
--- a/Extensions/Xtensive.Orm.Reprocessing/Configuration/ReprocessingConfiguration.cs
+++ b/Extensions/Xtensive.Orm.Reprocessing/Configuration/ReprocessingConfiguration.cs
@@ -1,4 +1,3 @@
-using System;
 using System.Configuration;
 using Xtensive.Core;
 
diff --git a/Extensions/Xtensive.Orm.Reprocessing/DomainBuildErrorEventArgs.cs b/Extensions/Xtensive.Orm.Reprocessing/DomainBuildErrorEventArgs.cs
index 99e0acb2b..f479b1e59 100644
--- a/Extensions/Xtensive.Orm.Reprocessing/DomainBuildErrorEventArgs.cs
+++ b/Extensions/Xtensive.Orm.Reprocessing/DomainBuildErrorEventArgs.cs
@@ -1,7 +1,6 @@
 // Copyright (C) 2012-2022 Xtensive LLC.
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
-using System;
 
 namespace Xtensive.Orm.Reprocessing
 {
diff --git a/Extensions/Xtensive.Orm.Reprocessing/DomainBuilder.cs b/Extensions/Xtensive.Orm.Reprocessing/DomainBuilder.cs
index db59efe07..355aae76e 100644
--- a/Extensions/Xtensive.Orm.Reprocessing/DomainBuilder.cs
+++ b/Extensions/Xtensive.Orm.Reprocessing/DomainBuilder.cs
@@ -1,5 +1,3 @@
-using System;
-using System.Linq;
 using System.Reflection;
 using Xtensive.Orm.Configuration;
 
diff --git a/Extensions/Xtensive.Orm.Reprocessing/DomainExtensions.cs b/Extensions/Xtensive.Orm.Reprocessing/DomainExtensions.cs
index 5e50e8118..8ce5d1588 100644
--- a/Extensions/Xtensive.Orm.Reprocessing/DomainExtensions.cs
+++ b/Extensions/Xtensive.Orm.Reprocessing/DomainExtensions.cs
@@ -1,4 +1,3 @@
-using System;
 using System.Transactions;
 using Xtensive.Orm.Reprocessing.Configuration;
 
diff --git a/Extensions/Xtensive.Orm.Reprocessing/ExecuteActionStrategy.cs b/Extensions/Xtensive.Orm.Reprocessing/ExecuteActionStrategy.cs
index bc1a68f30..05f15041c 100644
--- a/Extensions/Xtensive.Orm.Reprocessing/ExecuteActionStrategy.cs
+++ b/Extensions/Xtensive.Orm.Reprocessing/ExecuteActionStrategy.cs
@@ -1,4 +1,3 @@
-using System;
 using System.Collections.Concurrent;
 using System.Transactions;
 using Xtensive.Core;
diff --git a/Extensions/Xtensive.Orm.Reprocessing/ExecuteErrorEventArgs.cs b/Extensions/Xtensive.Orm.Reprocessing/ExecuteErrorEventArgs.cs
index 38e77a043..c43754445 100644
--- a/Extensions/Xtensive.Orm.Reprocessing/ExecuteErrorEventArgs.cs
+++ b/Extensions/Xtensive.Orm.Reprocessing/ExecuteErrorEventArgs.cs
@@ -2,7 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
 
 namespace Xtensive.Orm.Reprocessing
 {
diff --git a/Extensions/Xtensive.Orm.Reprocessing/ExecutionContext.cs b/Extensions/Xtensive.Orm.Reprocessing/ExecutionContext.cs
index d7fa7e631..5a93b7566 100644
--- a/Extensions/Xtensive.Orm.Reprocessing/ExecutionContext.cs
+++ b/Extensions/Xtensive.Orm.Reprocessing/ExecutionContext.cs
@@ -1,4 +1,3 @@
-using System;
 using System.Transactions;
 
 namespace Xtensive.Orm.Reprocessing
diff --git a/Extensions/Xtensive.Orm.Reprocessing/IExecuteActionStrategy.cs b/Extensions/Xtensive.Orm.Reprocessing/IExecuteActionStrategy.cs
index ba18032c1..b16433a73 100644
--- a/Extensions/Xtensive.Orm.Reprocessing/IExecuteActionStrategy.cs
+++ b/Extensions/Xtensive.Orm.Reprocessing/IExecuteActionStrategy.cs
@@ -1,4 +1,3 @@
-using System;
 
 namespace Xtensive.Orm.Reprocessing
 {
diff --git a/Extensions/Xtensive.Orm.Reprocessing/IExecuteConfiguration.cs b/Extensions/Xtensive.Orm.Reprocessing/IExecuteConfiguration.cs
index 357c83c29..b302e5d85 100644
--- a/Extensions/Xtensive.Orm.Reprocessing/IExecuteConfiguration.cs
+++ b/Extensions/Xtensive.Orm.Reprocessing/IExecuteConfiguration.cs
@@ -1,4 +1,3 @@
-using System;
 using System.Transactions;
 
 namespace Xtensive.Orm.Reprocessing
diff --git a/Extensions/Xtensive.Orm.Reprocessing/Internals/ExecuteConfiguration.cs b/Extensions/Xtensive.Orm.Reprocessing/Internals/ExecuteConfiguration.cs
index c8c9d1b76..6229c8cdf 100644
--- a/Extensions/Xtensive.Orm.Reprocessing/Internals/ExecuteConfiguration.cs
+++ b/Extensions/Xtensive.Orm.Reprocessing/Internals/ExecuteConfiguration.cs
@@ -1,4 +1,3 @@
-using System;
 using System.Transactions;
 
 namespace Xtensive.Orm.Reprocessing
diff --git a/Extensions/Xtensive.Orm.Reprocessing/ReprocessAttribute.cs b/Extensions/Xtensive.Orm.Reprocessing/ReprocessAttribute.cs
index 275c53630..4cab67c5d 100644
--- a/Extensions/Xtensive.Orm.Reprocessing/ReprocessAttribute.cs
+++ b/Extensions/Xtensive.Orm.Reprocessing/ReprocessAttribute.cs
@@ -1,6 +1,5 @@
 #if NOT_IMPLMENETED
 
-using System;
 using System.Transactions;
 using PostSharp.Aspects;
 
diff --git a/Extensions/Xtensive.Orm.Reprocessing/ReprocessableDomainBuilder.cs b/Extensions/Xtensive.Orm.Reprocessing/ReprocessableDomainBuilder.cs
index 803e0e941..dca4d2ecd 100644
--- a/Extensions/Xtensive.Orm.Reprocessing/ReprocessableDomainBuilder.cs
+++ b/Extensions/Xtensive.Orm.Reprocessing/ReprocessableDomainBuilder.cs
@@ -1,4 +1,3 @@
-using System;
 using Xtensive.Orm.Configuration;
 
 namespace Xtensive.Orm.Reprocessing
diff --git a/Extensions/Xtensive.Orm.Reprocessing/RollbackTransactionException.cs b/Extensions/Xtensive.Orm.Reprocessing/RollbackTransactionException.cs
index 005520f8c..37b17caf9 100644
--- a/Extensions/Xtensive.Orm.Reprocessing/RollbackTransactionException.cs
+++ b/Extensions/Xtensive.Orm.Reprocessing/RollbackTransactionException.cs
@@ -1,4 +1,3 @@
-using System;
 
 namespace Xtensive.Orm.Reprocessing
 {
diff --git a/Extensions/Xtensive.Orm.Security.Tests/Model/Branch.cs b/Extensions/Xtensive.Orm.Security.Tests/Model/Branch.cs
index d6b432f4f..4b757f99f 100644
--- a/Extensions/Xtensive.Orm.Security.Tests/Model/Branch.cs
+++ b/Extensions/Xtensive.Orm.Security.Tests/Model/Branch.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2011.06.26
 
-using System;
 using Xtensive.Orm;
 
 namespace Xtensive.Orm.Security.Tests.Model
diff --git a/Extensions/Xtensive.Orm.Security.Tests/Model/Employee.cs b/Extensions/Xtensive.Orm.Security.Tests/Model/Employee.cs
index 3f5d8272d..b688be88e 100644
--- a/Extensions/Xtensive.Orm.Security.Tests/Model/Employee.cs
+++ b/Extensions/Xtensive.Orm.Security.Tests/Model/Employee.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2011.05.30
 
-using System;
 using Xtensive.Orm;
 
 namespace Xtensive.Orm.Security.Tests.Model
diff --git a/Extensions/Xtensive.Orm.Security.Tests/Model/VipCustomer.cs b/Extensions/Xtensive.Orm.Security.Tests/Model/VipCustomer.cs
index 7565ba7b7..ccd9b25e8 100644
--- a/Extensions/Xtensive.Orm.Security.Tests/Model/VipCustomer.cs
+++ b/Extensions/Xtensive.Orm.Security.Tests/Model/VipCustomer.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2011.05.30
 
-using System;
 using Xtensive.Orm;
 
 namespace Xtensive.Orm.Security.Tests.Model
diff --git a/Extensions/Xtensive.Orm.Security.Tests/Permissions/CustomerPermission.cs b/Extensions/Xtensive.Orm.Security.Tests/Permissions/CustomerPermission.cs
index 4651e7b7a..6ebecb634 100644
--- a/Extensions/Xtensive.Orm.Security.Tests/Permissions/CustomerPermission.cs
+++ b/Extensions/Xtensive.Orm.Security.Tests/Permissions/CustomerPermission.cs
@@ -4,8 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2011.05.30
 
-using System;
-using System.Linq;
 using Xtensive.Orm;
 using Xtensive.Orm.Security.Tests.Model;
 
diff --git a/Extensions/Xtensive.Orm.Security.Tests/Permissions/VipCustomerPermission.cs b/Extensions/Xtensive.Orm.Security.Tests/Permissions/VipCustomerPermission.cs
index 79b9b2885..ee1bead41 100644
--- a/Extensions/Xtensive.Orm.Security.Tests/Permissions/VipCustomerPermission.cs
+++ b/Extensions/Xtensive.Orm.Security.Tests/Permissions/VipCustomerPermission.cs
@@ -4,8 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2011.05.30
 
-using System;
-using System.Linq;
 using Xtensive.Orm;
 using Xtensive.Orm.Security.Tests.Model;
 
diff --git a/Extensions/Xtensive.Orm.Security.Tests/Roles/AircraftManagerRole.cs b/Extensions/Xtensive.Orm.Security.Tests/Roles/AircraftManagerRole.cs
index 8e6679df8..a1cde6f81 100644
--- a/Extensions/Xtensive.Orm.Security.Tests/Roles/AircraftManagerRole.cs
+++ b/Extensions/Xtensive.Orm.Security.Tests/Roles/AircraftManagerRole.cs
@@ -4,8 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2011.05.30
 
-using System;
-using System.Linq;
 using Xtensive.Orm;
 using Xtensive.Orm.Security.Tests.Model;
 using Xtensive.Orm.Security.Tests.Permissions;
diff --git a/Extensions/Xtensive.Orm.Security.Tests/Roles/AutomobileManagerRole.cs b/Extensions/Xtensive.Orm.Security.Tests/Roles/AutomobileManagerRole.cs
index 435689741..805dba96c 100644
--- a/Extensions/Xtensive.Orm.Security.Tests/Roles/AutomobileManagerRole.cs
+++ b/Extensions/Xtensive.Orm.Security.Tests/Roles/AutomobileManagerRole.cs
@@ -4,8 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2011.05.30
 
-using System;
-using System.Linq;
 using Xtensive.Orm;
 using Xtensive.Orm.Security.Tests.Model;
 using Xtensive.Orm.Security.Tests.Permissions;
diff --git a/Extensions/Xtensive.Orm.Security.Tests/Roles/BranchOfficeManagerRole.cs b/Extensions/Xtensive.Orm.Security.Tests/Roles/BranchOfficeManagerRole.cs
index b6d91bc22..ef80cb569 100644
--- a/Extensions/Xtensive.Orm.Security.Tests/Roles/BranchOfficeManagerRole.cs
+++ b/Extensions/Xtensive.Orm.Security.Tests/Roles/BranchOfficeManagerRole.cs
@@ -4,8 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2011.06.26
 
-using System;
-using System.Linq;
 using Xtensive.Orm;
 using Xtensive.Orm.Security.Tests.Model;
 
diff --git a/Extensions/Xtensive.Orm.Security.Tests/Roles/SalesManagerRole.cs b/Extensions/Xtensive.Orm.Security.Tests/Roles/SalesManagerRole.cs
index 2a65a340a..db5a19083 100644
--- a/Extensions/Xtensive.Orm.Security.Tests/Roles/SalesManagerRole.cs
+++ b/Extensions/Xtensive.Orm.Security.Tests/Roles/SalesManagerRole.cs
@@ -4,8 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2011.05.30
 
-using System;
-using System.Linq;
 using Xtensive.Orm;
 using Xtensive.Orm.Security.Tests.Model;
 using Xtensive.Orm.Security.Tests.Permissions;
diff --git a/Extensions/Xtensive.Orm.Security.Tests/Roles/SalesPersonRole.cs b/Extensions/Xtensive.Orm.Security.Tests/Roles/SalesPersonRole.cs
index 3556bc327..b36710ba0 100644
--- a/Extensions/Xtensive.Orm.Security.Tests/Roles/SalesPersonRole.cs
+++ b/Extensions/Xtensive.Orm.Security.Tests/Roles/SalesPersonRole.cs
@@ -4,8 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2011.05.30
 
-using System;
-using System.Linq;
 using Xtensive.Orm;
 using Xtensive.Orm.Security.Tests.Model;
 using Xtensive.Orm.Security.Tests.Permissions;
diff --git a/Extensions/Xtensive.Orm.Security.Tests/SecurityTestBase.cs b/Extensions/Xtensive.Orm.Security.Tests/SecurityTestBase.cs
index a8235b2a1..c2a1be961 100644
--- a/Extensions/Xtensive.Orm.Security.Tests/SecurityTestBase.cs
+++ b/Extensions/Xtensive.Orm.Security.Tests/SecurityTestBase.cs
@@ -1,6 +1,5 @@
 using System.Configuration;
 using NUnit.Framework;
-using System;
 using TestCommon;
 using Xtensive.Core;
 using Xtensive.Orm;
diff --git a/Extensions/Xtensive.Orm.Security.Tests/Tests/HashingServicesTests.cs b/Extensions/Xtensive.Orm.Security.Tests/Tests/HashingServicesTests.cs
index 7f2506c25..151aa06df 100644
--- a/Extensions/Xtensive.Orm.Security.Tests/Tests/HashingServicesTests.cs
+++ b/Extensions/Xtensive.Orm.Security.Tests/Tests/HashingServicesTests.cs
@@ -4,9 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2011.05.30
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Reflection;
 using NUnit.Framework;
 using Xtensive.Orm.Security.Cryptography;
diff --git a/Extensions/Xtensive.Orm.Security.Tests/Tests/ImpersonationContextTests.cs b/Extensions/Xtensive.Orm.Security.Tests/Tests/ImpersonationContextTests.cs
index 76d77d79a..fe3df43e2 100644
--- a/Extensions/Xtensive.Orm.Security.Tests/Tests/ImpersonationContextTests.cs
+++ b/Extensions/Xtensive.Orm.Security.Tests/Tests/ImpersonationContextTests.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2011.05.30
 
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm;
 using Xtensive.Orm.Security.Tests.Model;
diff --git a/Extensions/Xtensive.Orm.Security.Tests/Tests/PermissionSetTests.cs b/Extensions/Xtensive.Orm.Security.Tests/Tests/PermissionSetTests.cs
index af4f499fe..80e081ee0 100644
--- a/Extensions/Xtensive.Orm.Security.Tests/Tests/PermissionSetTests.cs
+++ b/Extensions/Xtensive.Orm.Security.Tests/Tests/PermissionSetTests.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2011.05.30
 
-using System.Collections.Generic;
 using NUnit.Framework;
 using Xtensive.Orm;
 using Xtensive.Orm.Security.Tests.Model;
diff --git a/Extensions/Xtensive.Orm.Security/Configuration/Elements/AuthenticationServiceConfigurationElement.cs b/Extensions/Xtensive.Orm.Security/Configuration/Elements/AuthenticationServiceConfigurationElement.cs
index 86cdf4c05..2cc035169 100644
--- a/Extensions/Xtensive.Orm.Security/Configuration/Elements/AuthenticationServiceConfigurationElement.cs
+++ b/Extensions/Xtensive.Orm.Security/Configuration/Elements/AuthenticationServiceConfigurationElement.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2011.06.07
 
-using System;
 using System.Configuration;
 
 namespace Xtensive.Orm.Security.Configuration
diff --git a/Extensions/Xtensive.Orm.Security/Configuration/Elements/ConfigurationSection.cs b/Extensions/Xtensive.Orm.Security/Configuration/Elements/ConfigurationSection.cs
index ca3fe8cf0..328a2fcc3 100644
--- a/Extensions/Xtensive.Orm.Security/Configuration/Elements/ConfigurationSection.cs
+++ b/Extensions/Xtensive.Orm.Security/Configuration/Elements/ConfigurationSection.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2011.06.07
 
-using System;
 using System.Configuration;
 
 namespace Xtensive.Orm.Security.Configuration
diff --git a/Extensions/Xtensive.Orm.Security/Configuration/Elements/HashingServiceConfigurationElement.cs b/Extensions/Xtensive.Orm.Security/Configuration/Elements/HashingServiceConfigurationElement.cs
index 81be99299..13ef4576b 100644
--- a/Extensions/Xtensive.Orm.Security/Configuration/Elements/HashingServiceConfigurationElement.cs
+++ b/Extensions/Xtensive.Orm.Security/Configuration/Elements/HashingServiceConfigurationElement.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2011.06.07
 
-using System;
 using System.Configuration;
 
 namespace Xtensive.Orm.Security.Configuration
diff --git a/Extensions/Xtensive.Orm.Security/Configuration/SecurityConfiguration.cs b/Extensions/Xtensive.Orm.Security/Configuration/SecurityConfiguration.cs
index 8346a6497..ae837f7ce 100644
--- a/Extensions/Xtensive.Orm.Security/Configuration/SecurityConfiguration.cs
+++ b/Extensions/Xtensive.Orm.Security/Configuration/SecurityConfiguration.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2011.06.10
 
-using System;
 using System.Configuration;
 
 namespace Xtensive.Orm.Security.Configuration
diff --git a/Extensions/Xtensive.Orm.Security/Cryptography/GenericHashingService.cs b/Extensions/Xtensive.Orm.Security/Cryptography/GenericHashingService.cs
index ab591590f..321d3ad9b 100644
--- a/Extensions/Xtensive.Orm.Security/Cryptography/GenericHashingService.cs
+++ b/Extensions/Xtensive.Orm.Security/Cryptography/GenericHashingService.cs
@@ -4,8 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2011.06.10
 
-using System;
-using System.Linq;
 using System.Security.Cryptography;
 using System.Text;
 
diff --git a/Extensions/Xtensive.Orm.Security/Cryptography/PlainHashingService.cs b/Extensions/Xtensive.Orm.Security/Cryptography/PlainHashingService.cs
index db8ccfe31..02da26a17 100644
--- a/Extensions/Xtensive.Orm.Security/Cryptography/PlainHashingService.cs
+++ b/Extensions/Xtensive.Orm.Security/Cryptography/PlainHashingService.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2011.05.22
 
-using System;
 using Xtensive.IoC;
 
 namespace Xtensive.Orm.Security.Cryptography
diff --git a/Extensions/Xtensive.Orm.Security/GenericPrincipal.cs b/Extensions/Xtensive.Orm.Security/GenericPrincipal.cs
index 0fb4b87f2..b8c139837 100644
--- a/Extensions/Xtensive.Orm.Security/GenericPrincipal.cs
+++ b/Extensions/Xtensive.Orm.Security/GenericPrincipal.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2011.05.22
 
-using System;
 using Xtensive.Orm;
 using Xtensive.Orm.Security.Configuration;
 
diff --git a/Extensions/Xtensive.Orm.Security/ImpersonationContext.cs b/Extensions/Xtensive.Orm.Security/ImpersonationContext.cs
index 2987438f6..130a3d881 100644
--- a/Extensions/Xtensive.Orm.Security/ImpersonationContext.cs
+++ b/Extensions/Xtensive.Orm.Security/ImpersonationContext.cs
@@ -1,4 +1,3 @@
-using System;
 using Xtensive.Core;
 
 namespace Xtensive.Orm.Security
diff --git a/Extensions/Xtensive.Orm.Security/Interfaces/IRole.cs b/Extensions/Xtensive.Orm.Security/Interfaces/IRole.cs
index e0c593768..f6d57d5a9 100644
--- a/Extensions/Xtensive.Orm.Security/Interfaces/IRole.cs
+++ b/Extensions/Xtensive.Orm.Security/Interfaces/IRole.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2011.06.26
 
-using System.Collections.Generic;
 using Xtensive.Orm;
 
 namespace Xtensive.Orm.Security
diff --git a/Extensions/Xtensive.Orm.Security/Permission.cs b/Extensions/Xtensive.Orm.Security/Permission.cs
index 0766b6291..106b5c384 100644
--- a/Extensions/Xtensive.Orm.Security/Permission.cs
+++ b/Extensions/Xtensive.Orm.Security/Permission.cs
@@ -4,8 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2011.06.10
 
-using System;
-using System.Linq;
 using Xtensive.Orm;
 
 namespace Xtensive.Orm.Security
diff --git a/Extensions/Xtensive.Orm.Security/PermissionSet.cs b/Extensions/Xtensive.Orm.Security/PermissionSet.cs
index dce583dc1..026980a06 100644
--- a/Extensions/Xtensive.Orm.Security/PermissionSet.cs
+++ b/Extensions/Xtensive.Orm.Security/PermissionSet.cs
@@ -1,6 +1,4 @@
-using System;
 using System.Collections;
-using System.Collections.Generic;
 
 namespace Xtensive.Orm.Security
 {
diff --git a/Extensions/Xtensive.Orm.Security/Principal.cs b/Extensions/Xtensive.Orm.Security/Principal.cs
index 5ea068976..3277e5803 100644
--- a/Extensions/Xtensive.Orm.Security/Principal.cs
+++ b/Extensions/Xtensive.Orm.Security/Principal.cs
@@ -1,4 +1,3 @@
-using System.Linq;
 using System.Security.Principal;
 using Xtensive.Orm.Validation;
 
diff --git a/Extensions/Xtensive.Orm.Security/Role.cs b/Extensions/Xtensive.Orm.Security/Role.cs
index 0d2a25a2f..faedf8a0e 100644
--- a/Extensions/Xtensive.Orm.Security/Role.cs
+++ b/Extensions/Xtensive.Orm.Security/Role.cs
@@ -1,4 +1,3 @@
-using System.Collections.Generic;
 using Xtensive.Collections;
 using Xtensive.Orm.Validation;
 
diff --git a/Extensions/Xtensive.Orm.Security/SecureQueryRootBuilder.cs b/Extensions/Xtensive.Orm.Security/SecureQueryRootBuilder.cs
index 4bf8042d4..5f8abff22 100644
--- a/Extensions/Xtensive.Orm.Security/SecureQueryRootBuilder.cs
+++ b/Extensions/Xtensive.Orm.Security/SecureQueryRootBuilder.cs
@@ -4,9 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2011.05.22
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Linq.Expressions;
 using Xtensive.Linq;
 using Xtensive.Orm;
diff --git a/Extensions/Xtensive.Orm.Security/Services/GenericAuthenticationService.cs b/Extensions/Xtensive.Orm.Security/Services/GenericAuthenticationService.cs
index 719c83ac0..326ed67eb 100644
--- a/Extensions/Xtensive.Orm.Security/Services/GenericAuthenticationService.cs
+++ b/Extensions/Xtensive.Orm.Security/Services/GenericAuthenticationService.cs
@@ -4,8 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2011.03.16
 
-using System;
-using System.Linq;
 using System.Security.Principal;
 using Xtensive.Core;
 using Xtensive.IoC;
diff --git a/Extensions/Xtensive.Orm.Tracking.Tests/Model/MyEntity.cs b/Extensions/Xtensive.Orm.Tracking.Tests/Model/MyEntity.cs
index 6a7bebe7f..a97f548cb 100644
--- a/Extensions/Xtensive.Orm.Tracking.Tests/Model/MyEntity.cs
+++ b/Extensions/Xtensive.Orm.Tracking.Tests/Model/MyEntity.cs
@@ -1,4 +1,3 @@
-using System;
 
 namespace Xtensive.Orm.Tracking.Tests.Model
 {
diff --git a/Extensions/Xtensive.Orm.Tracking.Tests/Model/MyEntitySetItem.cs b/Extensions/Xtensive.Orm.Tracking.Tests/Model/MyEntitySetItem.cs
index cc9e97f15..f905f5824 100644
--- a/Extensions/Xtensive.Orm.Tracking.Tests/Model/MyEntitySetItem.cs
+++ b/Extensions/Xtensive.Orm.Tracking.Tests/Model/MyEntitySetItem.cs
@@ -1,6 +1,3 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Text;
 using Xtensive.Orm;
 
diff --git a/Extensions/Xtensive.Orm.Tracking.Tests/Model/MyEnum.cs b/Extensions/Xtensive.Orm.Tracking.Tests/Model/MyEnum.cs
index 2c684efee..b8a23d862 100644
--- a/Extensions/Xtensive.Orm.Tracking.Tests/Model/MyEnum.cs
+++ b/Extensions/Xtensive.Orm.Tracking.Tests/Model/MyEnum.cs
@@ -1,6 +1,3 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Text;
 
 namespace Xtensive.Orm.Tracking.Tests.Model
diff --git a/Extensions/Xtensive.Orm.Tracking.Tests/Model/MyReferenceProperty.cs b/Extensions/Xtensive.Orm.Tracking.Tests/Model/MyReferenceProperty.cs
index 1482804f6..9ee6704e8 100644
--- a/Extensions/Xtensive.Orm.Tracking.Tests/Model/MyReferenceProperty.cs
+++ b/Extensions/Xtensive.Orm.Tracking.Tests/Model/MyReferenceProperty.cs
@@ -1,6 +1,3 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Text;
 using Xtensive.Orm;
 
diff --git a/Extensions/Xtensive.Orm.Tracking.Tests/Model/MyStructure.cs b/Extensions/Xtensive.Orm.Tracking.Tests/Model/MyStructure.cs
index e79e66a0c..21579342a 100644
--- a/Extensions/Xtensive.Orm.Tracking.Tests/Model/MyStructure.cs
+++ b/Extensions/Xtensive.Orm.Tracking.Tests/Model/MyStructure.cs
@@ -1,6 +1,3 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Text;
 using Xtensive.Orm;
 
diff --git a/Extensions/Xtensive.Orm.Tracking.Tests/TestHelper.cs b/Extensions/Xtensive.Orm.Tracking.Tests/TestHelper.cs
index f867e3ba3..49e8066e7 100644
--- a/Extensions/Xtensive.Orm.Tracking.Tests/TestHelper.cs
+++ b/Extensions/Xtensive.Orm.Tracking.Tests/TestHelper.cs
@@ -1,4 +1,3 @@
-using System;
 using System.Reflection;
 using Xtensive.Tuples;
 using Tuple = Xtensive.Tuples.Tuple;
diff --git a/Extensions/Xtensive.Orm.Tracking.Tests/TrackingMonitorTests.cs b/Extensions/Xtensive.Orm.Tracking.Tests/TrackingMonitorTests.cs
index 5366b8df8..e5897111b 100644
--- a/Extensions/Xtensive.Orm.Tracking.Tests/TrackingMonitorTests.cs
+++ b/Extensions/Xtensive.Orm.Tracking.Tests/TrackingMonitorTests.cs
@@ -4,8 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2012.05.17
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Tracking.Tests.Model;
 
diff --git a/Extensions/Xtensive.Orm.Tracking.Tests/TrackingStackFrameTests.cs b/Extensions/Xtensive.Orm.Tracking.Tests/TrackingStackFrameTests.cs
index ea972614a..bf92a1058 100644
--- a/Extensions/Xtensive.Orm.Tracking.Tests/TrackingStackFrameTests.cs
+++ b/Extensions/Xtensive.Orm.Tracking.Tests/TrackingStackFrameTests.cs
@@ -1,4 +1,3 @@
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Tracking;
 using Xtensive.Orm.Tracking.Tests.Model;
diff --git a/Extensions/Xtensive.Orm.Tracking.Tests/TrackingTestBase.cs b/Extensions/Xtensive.Orm.Tracking.Tests/TrackingTestBase.cs
index d2f2ad604..3c248948f 100644
--- a/Extensions/Xtensive.Orm.Tracking.Tests/TrackingTestBase.cs
+++ b/Extensions/Xtensive.Orm.Tracking.Tests/TrackingTestBase.cs
@@ -1,5 +1,4 @@
 using NUnit.Framework;
-using System;
 using TestCommon;
 using Xtensive.Core;
 using Xtensive.Orm.Tracking.Tests.Model;
diff --git a/Extensions/Xtensive.Orm.Tracking/Interfaces/IDomainTrackingMonitor.cs b/Extensions/Xtensive.Orm.Tracking/Interfaces/IDomainTrackingMonitor.cs
index fa7d8ff33..0d8e1d550 100644
--- a/Extensions/Xtensive.Orm.Tracking/Interfaces/IDomainTrackingMonitor.cs
+++ b/Extensions/Xtensive.Orm.Tracking/Interfaces/IDomainTrackingMonitor.cs
@@ -1,4 +1,3 @@
-using System;
 
 namespace Xtensive.Orm.Tracking
 {
diff --git a/Extensions/Xtensive.Orm.Tracking/Interfaces/ITrackingItem.cs b/Extensions/Xtensive.Orm.Tracking/Interfaces/ITrackingItem.cs
index e8e952bde..218729d49 100644
--- a/Extensions/Xtensive.Orm.Tracking/Interfaces/ITrackingItem.cs
+++ b/Extensions/Xtensive.Orm.Tracking/Interfaces/ITrackingItem.cs
@@ -2,7 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System.Collections.Generic;
 using Xtensive.Tuples;
 
 namespace Xtensive.Orm.Tracking
diff --git a/Extensions/Xtensive.Orm.Tracking/Interfaces/ITrackingMonitor.cs b/Extensions/Xtensive.Orm.Tracking/Interfaces/ITrackingMonitor.cs
index 4a3d3fda3..ce6ca6b8d 100644
--- a/Extensions/Xtensive.Orm.Tracking/Interfaces/ITrackingMonitor.cs
+++ b/Extensions/Xtensive.Orm.Tracking/Interfaces/ITrackingMonitor.cs
@@ -1,4 +1,3 @@
-using System;
 
 namespace Xtensive.Orm.Tracking
 {
diff --git a/Extensions/Xtensive.Orm.Tracking/Internals/DomainTrackingMonitor.cs b/Extensions/Xtensive.Orm.Tracking/Internals/DomainTrackingMonitor.cs
index 3271f983e..6ed69dc1c 100644
--- a/Extensions/Xtensive.Orm.Tracking/Internals/DomainTrackingMonitor.cs
+++ b/Extensions/Xtensive.Orm.Tracking/Internals/DomainTrackingMonitor.cs
@@ -1,4 +1,3 @@
-using System;
 using Xtensive.IoC;
 
 namespace Xtensive.Orm.Tracking
diff --git a/Extensions/Xtensive.Orm.Tracking/Internals/SessionTrackingMonitor.cs b/Extensions/Xtensive.Orm.Tracking/Internals/SessionTrackingMonitor.cs
index d75ea2991..f2d4d0618 100644
--- a/Extensions/Xtensive.Orm.Tracking/Internals/SessionTrackingMonitor.cs
+++ b/Extensions/Xtensive.Orm.Tracking/Internals/SessionTrackingMonitor.cs
@@ -2,9 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.IoC;
 using Xtensive.Orm.Services;
 
diff --git a/Extensions/Xtensive.Orm.Tracking/Internals/TrackingItem.cs b/Extensions/Xtensive.Orm.Tracking/Internals/TrackingItem.cs
index f89eb3169..ed5873d79 100644
--- a/Extensions/Xtensive.Orm.Tracking/Internals/TrackingItem.cs
+++ b/Extensions/Xtensive.Orm.Tracking/Internals/TrackingItem.cs
@@ -4,10 +4,7 @@
 // Created by: Dmitri Maximov
 // Created:    2012.05.16
 
-using System;
-using System.Collections.Generic;
 using System.Diagnostics;
-using System.Linq;
 using Xtensive.Tuples;
 using Tuple = Xtensive.Tuples.Tuple;
 
diff --git a/Extensions/Xtensive.Orm.Tracking/Internals/TrackingMonitor.cs b/Extensions/Xtensive.Orm.Tracking/Internals/TrackingMonitor.cs
index 9ff7bc6ff..5f2dedda5 100644
--- a/Extensions/Xtensive.Orm.Tracking/Internals/TrackingMonitor.cs
+++ b/Extensions/Xtensive.Orm.Tracking/Internals/TrackingMonitor.cs
@@ -1,4 +1,3 @@
-using System;
 
 namespace Xtensive.Orm.Tracking
 {
diff --git a/Extensions/Xtensive.Orm.Tracking/Internals/TrackingStackFrame.cs b/Extensions/Xtensive.Orm.Tracking/Internals/TrackingStackFrame.cs
index be2efa7bd..dad798bed 100644
--- a/Extensions/Xtensive.Orm.Tracking/Internals/TrackingStackFrame.cs
+++ b/Extensions/Xtensive.Orm.Tracking/Internals/TrackingStackFrame.cs
@@ -5,7 +5,6 @@
 // Created:    2012.05.16
 
 using System.Collections;
-using System.Collections.Generic;
 using Xtensive.Core;
 
 namespace Xtensive.Orm.Tracking
diff --git a/Extensions/Xtensive.Orm.Tracking/TrackingCompletedEventArgs.cs b/Extensions/Xtensive.Orm.Tracking/TrackingCompletedEventArgs.cs
index c53101c1d..6d1da541b 100644
--- a/Extensions/Xtensive.Orm.Tracking/TrackingCompletedEventArgs.cs
+++ b/Extensions/Xtensive.Orm.Tracking/TrackingCompletedEventArgs.cs
@@ -2,8 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Collections.Generic;
 
 namespace Xtensive.Orm.Tracking
 {
diff --git a/Extensions/Xtensive.Orm.Tracking/TrackingItemState.cs b/Extensions/Xtensive.Orm.Tracking/TrackingItemState.cs
index 7fb1fec5d..d0ce9b939 100644
--- a/Extensions/Xtensive.Orm.Tracking/TrackingItemState.cs
+++ b/Extensions/Xtensive.Orm.Tracking/TrackingItemState.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2012.05.16
 
-using System;
 
 namespace Xtensive.Orm.Tracking
 {
diff --git a/Extensions/Xtensive.Orm.Web.Tests/ActionFilterTest.cs b/Extensions/Xtensive.Orm.Web.Tests/ActionFilterTest.cs
index 2abff0bed..9b9f57540 100644
--- a/Extensions/Xtensive.Orm.Web.Tests/ActionFilterTest.cs
+++ b/Extensions/Xtensive.Orm.Web.Tests/ActionFilterTest.cs
@@ -1,13 +1,10 @@
-using System;
 using System.Net;
-using System.Threading.Tasks;
 using Microsoft.AspNetCore.TestHost;
 using Microsoft.Extensions.Hosting;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.AspNetCore.Mvc;
 using NUnit.Framework;
 using Xtensive.Orm.Web.Tests.Filters;
-using System.Linq;
 using System.Diagnostics.CodeAnalysis;
 
 namespace Xtensive.Orm.Web.Tests.Filters
diff --git a/Extensions/Xtensive.Orm.Web.Tests/MiddlewareTest.cs b/Extensions/Xtensive.Orm.Web.Tests/MiddlewareTest.cs
index f1890b922..e1ccd212d 100644
--- a/Extensions/Xtensive.Orm.Web.Tests/MiddlewareTest.cs
+++ b/Extensions/Xtensive.Orm.Web.Tests/MiddlewareTest.cs
@@ -2,9 +2,7 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
 using System.Net;
-using System.Threading.Tasks;
 using Microsoft.AspNetCore.TestHost;
 using Microsoft.Extensions.Hosting;
 using Microsoft.Extensions.DependencyInjection;
@@ -12,7 +10,6 @@
 using NUnit.Framework;
 using Xtensive.Orm.Web.Tests.Middleware;
 using Microsoft.AspNetCore.Builder;
-using System.Linq;
 using System.Diagnostics.CodeAnalysis;
 
 namespace Xtensive.Orm.Web.Tests.Middleware
diff --git a/Extensions/Xtensive.Orm.Web.Tests/WebTestBase.cs b/Extensions/Xtensive.Orm.Web.Tests/WebTestBase.cs
index 8e4bfe491..af34a7ffe 100644
--- a/Extensions/Xtensive.Orm.Web.Tests/WebTestBase.cs
+++ b/Extensions/Xtensive.Orm.Web.Tests/WebTestBase.cs
@@ -7,7 +7,6 @@
 using Microsoft.Extensions.Hosting;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.AspNetCore.Builder;
-using System;
 using Xtensive.Orm.Tests;
 using Xtensive.Orm.Configuration;
 
diff --git a/Extensions/Xtensive.Orm.Web/Filters/SessionActionFilter.cs b/Extensions/Xtensive.Orm.Web/Filters/SessionActionFilter.cs
index e602d7e40..38da5b2fa 100644
--- a/Extensions/Xtensive.Orm.Web/Filters/SessionActionFilter.cs
+++ b/Extensions/Xtensive.Orm.Web/Filters/SessionActionFilter.cs
@@ -2,8 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Threading.Tasks;
 using Microsoft.AspNetCore.Http;
 using Microsoft.AspNetCore.Mvc.Filters;
 using Xtensive.Core;
diff --git a/Extensions/Xtensive.Orm.Web/Middleware/OpenSessionMiddleware.cs b/Extensions/Xtensive.Orm.Web/Middleware/OpenSessionMiddleware.cs
index 943443170..f19f2097a 100644
--- a/Extensions/Xtensive.Orm.Web/Middleware/OpenSessionMiddleware.cs
+++ b/Extensions/Xtensive.Orm.Web/Middleware/OpenSessionMiddleware.cs
@@ -2,9 +2,7 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
 using Microsoft.AspNetCore.Http;
-using System.Threading.Tasks;
 using System.Runtime.ExceptionServices;
 
 namespace Xtensive.Orm.Web.Middleware
diff --git a/Extensions/Xtensive.Orm.Web/SessionAccessor.cs b/Extensions/Xtensive.Orm.Web/SessionAccessor.cs
index 6f3e64c73..a363d73b0 100644
--- a/Extensions/Xtensive.Orm.Web/SessionAccessor.cs
+++ b/Extensions/Xtensive.Orm.Web/SessionAccessor.cs
@@ -2,7 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
 using Xtensive.Core;
 using Microsoft.AspNetCore.Http;
 
diff --git a/Extensions/Xtensive.Orm.Web/StartupConfigurationExtensions.cs b/Extensions/Xtensive.Orm.Web/StartupConfigurationExtensions.cs
index 52891c421..b33bf4cfc 100644
--- a/Extensions/Xtensive.Orm.Web/StartupConfigurationExtensions.cs
+++ b/Extensions/Xtensive.Orm.Web/StartupConfigurationExtensions.cs
@@ -2,7 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
 using Microsoft.AspNetCore.Builder;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.AspNetCore.Mvc.Filters;
diff --git a/Extensions/Xtensive.Orm.Web/WellKnownTypes.cs b/Extensions/Xtensive.Orm.Web/WellKnownTypes.cs
index 8bd7ff88f..2fa436bdc 100644
--- a/Extensions/Xtensive.Orm.Web/WellKnownTypes.cs
+++ b/Extensions/Xtensive.Orm.Web/WellKnownTypes.cs
@@ -2,7 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
 using Xtensive.Orm.Web.Filters;
 
 namespace Xtensive.Orm.Web
diff --git a/Orm/Xtensive.Orm.Firebird/Sql.Drivers.Firebird/Connection.cs b/Orm/Xtensive.Orm.Firebird/Sql.Drivers.Firebird/Connection.cs
index eb238b3de..dbd8a629d 100644
--- a/Orm/Xtensive.Orm.Firebird/Sql.Drivers.Firebird/Connection.cs
+++ b/Orm/Xtensive.Orm.Firebird/Sql.Drivers.Firebird/Connection.cs
@@ -4,7 +4,6 @@
 // Created by: Csaba Beer
 // Created:    2011.01.08
 
-using System;
 using System.Data;
 using System.Data.Common;
 using FirebirdSql.Data.FirebirdClient;
diff --git a/Orm/Xtensive.Orm.Firebird/Sql.Drivers.Firebird/Constants.cs b/Orm/Xtensive.Orm.Firebird/Sql.Drivers.Firebird/Constants.cs
index f9e4e0069..dc360b8fd 100644
--- a/Orm/Xtensive.Orm.Firebird/Sql.Drivers.Firebird/Constants.cs
+++ b/Orm/Xtensive.Orm.Firebird/Sql.Drivers.Firebird/Constants.cs
@@ -4,7 +4,6 @@
 // Created by: Csaba Beer
 // Created:    2011.01.08
 
-using System;
 
 namespace Xtensive.Sql.Drivers.Firebird
 {
diff --git a/Orm/Xtensive.Orm.Firebird/Sql.Drivers.Firebird/Driver.cs b/Orm/Xtensive.Orm.Firebird/Sql.Drivers.Firebird/Driver.cs
index ffef452db..71fd60cec 100644
--- a/Orm/Xtensive.Orm.Firebird/Sql.Drivers.Firebird/Driver.cs
+++ b/Orm/Xtensive.Orm.Firebird/Sql.Drivers.Firebird/Driver.cs
@@ -4,7 +4,6 @@
 // Created by: Csaba Beer
 // Created:    2011.01.08
 
-using System.Linq;
 using Xtensive.Sql.Info;
 using FirebirdSql.Data.FirebirdClient;
 
diff --git a/Orm/Xtensive.Orm.Firebird/Sql.Drivers.Firebird/DriverFactory.cs b/Orm/Xtensive.Orm.Firebird/Sql.Drivers.Firebird/DriverFactory.cs
index cee9b08bd..524291533 100644
--- a/Orm/Xtensive.Orm.Firebird/Sql.Drivers.Firebird/DriverFactory.cs
+++ b/Orm/Xtensive.Orm.Firebird/Sql.Drivers.Firebird/DriverFactory.cs
@@ -4,11 +4,8 @@
 // Created by: Csaba Beer
 // Created:    2011.01.08
 
-using System;
 using System.Data.Common;
 using System.Text.RegularExpressions;
-using System.Threading;
-using System.Threading.Tasks;
 using FirebirdSql.Data.FirebirdClient;
 using Xtensive.Core;
 using Xtensive.Orm;
diff --git a/Orm/Xtensive.Orm.Firebird/Sql.Drivers.Firebird/Resources/Strings.Designer.cs b/Orm/Xtensive.Orm.Firebird/Sql.Drivers.Firebird/Resources/Strings.Designer.cs
index 55c1209a2..7a7f9cb02 100644
--- a/Orm/Xtensive.Orm.Firebird/Sql.Drivers.Firebird/Resources/Strings.Designer.cs
+++ b/Orm/Xtensive.Orm.Firebird/Sql.Drivers.Firebird/Resources/Strings.Designer.cs
@@ -9,7 +9,6 @@
 //------------------------------------------------------------------------------
 
 namespace Xtensive.Sql.Drivers.Firebird.Resources {
-    using System;
     
     
     /// <summary>
diff --git a/Orm/Xtensive.Orm.Firebird/Sql.Drivers.Firebird/v2_5/Compiler.cs b/Orm/Xtensive.Orm.Firebird/Sql.Drivers.Firebird/v2_5/Compiler.cs
index 2298b13e5..6f80c2210 100644
--- a/Orm/Xtensive.Orm.Firebird/Sql.Drivers.Firebird/v2_5/Compiler.cs
+++ b/Orm/Xtensive.Orm.Firebird/Sql.Drivers.Firebird/v2_5/Compiler.cs
@@ -4,13 +4,10 @@
 // Created by: Csaba Beer
 // Created:    2011.01.17
 
-using System;
-using System.Linq;
 using Xtensive.Sql.Compiler;
 using Xtensive.Sql.Ddl;
 using Xtensive.Sql.Dml;
 using Xtensive.Core;
-using System.Collections.Generic;
 
 namespace Xtensive.Sql.Drivers.Firebird.v2_5
 {
diff --git a/Orm/Xtensive.Orm.Firebird/Sql.Drivers.Firebird/v2_5/Driver.cs b/Orm/Xtensive.Orm.Firebird/Sql.Drivers.Firebird/v2_5/Driver.cs
index f915c31c8..26afbf6b1 100644
--- a/Orm/Xtensive.Orm.Firebird/Sql.Drivers.Firebird/v2_5/Driver.cs
+++ b/Orm/Xtensive.Orm.Firebird/Sql.Drivers.Firebird/v2_5/Driver.cs
@@ -4,7 +4,6 @@
 // Created by: Csaba Beer
 // Created:    2011.01.10
 
-using System;
 using Xtensive.Sql.Info;
 using Xtensive.Sql.Compiler;
 
diff --git a/Orm/Xtensive.Orm.Firebird/Sql.Drivers.Firebird/v2_5/Extractor.Queries.cs b/Orm/Xtensive.Orm.Firebird/Sql.Drivers.Firebird/v2_5/Extractor.Queries.cs
index 5fc48fe69..fee58861c 100644
--- a/Orm/Xtensive.Orm.Firebird/Sql.Drivers.Firebird/v2_5/Extractor.Queries.cs
+++ b/Orm/Xtensive.Orm.Firebird/Sql.Drivers.Firebird/v2_5/Extractor.Queries.cs
@@ -4,7 +4,6 @@
 // Created by: Csaba Beer
 // Created:    2011.01.13
 
-using System;
 
 namespace Xtensive.Sql.Drivers.Firebird.v2_5
 {
diff --git a/Orm/Xtensive.Orm.Firebird/Sql.Drivers.Firebird/v2_5/Extractor.cs b/Orm/Xtensive.Orm.Firebird/Sql.Drivers.Firebird/v2_5/Extractor.cs
index 9a6512aba..c32740ca3 100644
--- a/Orm/Xtensive.Orm.Firebird/Sql.Drivers.Firebird/v2_5/Extractor.cs
+++ b/Orm/Xtensive.Orm.Firebird/Sql.Drivers.Firebird/v2_5/Extractor.cs
@@ -4,12 +4,8 @@
 // Created by: Csaba Beer
 // Created:    2011.01.13
 
-using System;
-using System.Collections.Generic;
 using System.Data;
 using System.Data.Common;
-using System.Threading;
-using System.Threading.Tasks;
 using Xtensive.Sql.Drivers.Firebird.Resources;
 using Xtensive.Sql.Model;
 using Constraint = Xtensive.Sql.Model.Constraint;
diff --git a/Orm/Xtensive.Orm.Firebird/Sql.Drivers.Firebird/v2_5/ServerInfoProvider.cs b/Orm/Xtensive.Orm.Firebird/Sql.Drivers.Firebird/v2_5/ServerInfoProvider.cs
index f3d73c9ab..d0db88000 100644
--- a/Orm/Xtensive.Orm.Firebird/Sql.Drivers.Firebird/v2_5/ServerInfoProvider.cs
+++ b/Orm/Xtensive.Orm.Firebird/Sql.Drivers.Firebird/v2_5/ServerInfoProvider.cs
@@ -4,7 +4,6 @@
 // Created by: Csaba Beer
 // Created:    2011.01.10
 
-using System;
 using Xtensive.Sql.Info;
 
 namespace Xtensive.Sql.Drivers.Firebird.v2_5
diff --git a/Orm/Xtensive.Orm.Firebird/Sql.Drivers.Firebird/v2_5/Translator.cs b/Orm/Xtensive.Orm.Firebird/Sql.Drivers.Firebird/v2_5/Translator.cs
index 9e6d9b16c..0f8b1aa9c 100644
--- a/Orm/Xtensive.Orm.Firebird/Sql.Drivers.Firebird/v2_5/Translator.cs
+++ b/Orm/Xtensive.Orm.Firebird/Sql.Drivers.Firebird/v2_5/Translator.cs
@@ -4,9 +4,7 @@
 // Created by: Csaba Beer
 // Created:    2011.01.17
 
-using System.Linq;
 using Xtensive.Sql.Compiler;
-using System;
 using System.Text;
 using Xtensive.Core;
 using Xtensive.Sql.Dml;
diff --git a/Orm/Xtensive.Orm.Firebird/Sql.Drivers.Firebird/v2_5/TypeMapper.cs b/Orm/Xtensive.Orm.Firebird/Sql.Drivers.Firebird/v2_5/TypeMapper.cs
index 6816888c7..de264f4e2 100644
--- a/Orm/Xtensive.Orm.Firebird/Sql.Drivers.Firebird/v2_5/TypeMapper.cs
+++ b/Orm/Xtensive.Orm.Firebird/Sql.Drivers.Firebird/v2_5/TypeMapper.cs
@@ -4,7 +4,6 @@
 // Created by: Csaba Beer
 // Created:    2011.01.10
 
-using System;
 using System.Data.Common;
 using System.Data;
 
diff --git a/Orm/Xtensive.Orm.Firebird/Sql.Drivers.Firebird/v4_0/Compiler.cs b/Orm/Xtensive.Orm.Firebird/Sql.Drivers.Firebird/v4_0/Compiler.cs
index 749d2f39c..adfd9acd2 100644
--- a/Orm/Xtensive.Orm.Firebird/Sql.Drivers.Firebird/v4_0/Compiler.cs
+++ b/Orm/Xtensive.Orm.Firebird/Sql.Drivers.Firebird/v4_0/Compiler.cs
@@ -2,8 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Collections.Generic;
 using System.Text;
 
 namespace Xtensive.Sql.Drivers.Firebird.v4_0
diff --git a/Orm/Xtensive.Orm.Firebird/Sql.Drivers.Firebird/v4_0/Driver.cs b/Orm/Xtensive.Orm.Firebird/Sql.Drivers.Firebird/v4_0/Driver.cs
index 20263c375..d795b688b 100644
--- a/Orm/Xtensive.Orm.Firebird/Sql.Drivers.Firebird/v4_0/Driver.cs
+++ b/Orm/Xtensive.Orm.Firebird/Sql.Drivers.Firebird/v4_0/Driver.cs
@@ -2,7 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
 using Xtensive.Sql.Info;
 using Xtensive.Sql.Compiler;
 
diff --git a/Orm/Xtensive.Orm.Firebird/Sql.Drivers.Firebird/v4_0/Extractor.cs b/Orm/Xtensive.Orm.Firebird/Sql.Drivers.Firebird/v4_0/Extractor.cs
index 10e78ce94..16f800ece 100644
--- a/Orm/Xtensive.Orm.Firebird/Sql.Drivers.Firebird/v4_0/Extractor.cs
+++ b/Orm/Xtensive.Orm.Firebird/Sql.Drivers.Firebird/v4_0/Extractor.cs
@@ -2,13 +2,9 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Collections.Generic;
 using System.Data;
 using System.Data.Common;
 using System.Text;
-using System.Threading;
-using System.Threading.Tasks;
 using Xtensive.Core;
 using Xtensive.Sql.Dml;
 using Xtensive.Sql.Drivers.Firebird.Resources;
diff --git a/Orm/Xtensive.Orm.Firebird/Sql.Drivers.Firebird/v4_0/TypeMapper.cs b/Orm/Xtensive.Orm.Firebird/Sql.Drivers.Firebird/v4_0/TypeMapper.cs
index 3d7388f05..3107dfae6 100644
--- a/Orm/Xtensive.Orm.Firebird/Sql.Drivers.Firebird/v4_0/TypeMapper.cs
+++ b/Orm/Xtensive.Orm.Firebird/Sql.Drivers.Firebird/v4_0/TypeMapper.cs
@@ -2,7 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
 using System.Data.Common;
 using System.Numerics;
 using System.Text;
diff --git a/Orm/Xtensive.Orm.Manual/Advanced/CustomLinqCompilerTest.cs b/Orm/Xtensive.Orm.Manual/Advanced/CustomLinqCompilerTest.cs
index a5a0d3804..47b88cbe0 100644
--- a/Orm/Xtensive.Orm.Manual/Advanced/CustomLinqCompilerTest.cs
+++ b/Orm/Xtensive.Orm.Manual/Advanced/CustomLinqCompilerTest.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2009.11.16
 
-using System;
-using System.Linq;
 using System.Linq.Expressions;
 using NUnit.Framework;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm.Manual/Advanced/CustomSqlCompilerTest.cs b/Orm/Xtensive.Orm.Manual/Advanced/CustomSqlCompilerTest.cs
index dc3b631f3..de043a8af 100644
--- a/Orm/Xtensive.Orm.Manual/Advanced/CustomSqlCompilerTest.cs
+++ b/Orm/Xtensive.Orm.Manual/Advanced/CustomSqlCompilerTest.cs
@@ -4,13 +4,11 @@
 // Created by: Alexey Gamzov
 // Created:    2009.11.11
 
-using System;
 using NUnit.Framework;
 using Xtensive.Linq;
 using Xtensive.Orm.Tests;
 using Xtensive.Sql;
 using Xtensive.Sql.Dml;
-using System.Linq;
 
 namespace Xtensive.Orm.Manual.Advanced.CustomSqlCompiler
 {
diff --git a/Orm/Xtensive.Orm.Manual/Advanced/JoinsAndSubqueriesTest.cs b/Orm/Xtensive.Orm.Manual/Advanced/JoinsAndSubqueriesTest.cs
index d870e15be..f01bf7240 100644
--- a/Orm/Xtensive.Orm.Manual/Advanced/JoinsAndSubqueriesTest.cs
+++ b/Orm/Xtensive.Orm.Manual/Advanced/JoinsAndSubqueriesTest.cs
@@ -4,9 +4,7 @@
 // Created by: Alexey Gamzov
 // Created:    2009.11.24
 
-using System;
 using NUnit.Framework;
-using System.Linq;
 using Xtensive.Orm.Tests;
 
 namespace Xtensive.Orm.Manual.Advanced.JoinsAndSubqueriesTest
diff --git a/Orm/Xtensive.Orm.Manual/Attributes/AttributesTest.cs b/Orm/Xtensive.Orm.Manual/Attributes/AttributesTest.cs
index 69641ff41..2e85d0711 100644
--- a/Orm/Xtensive.Orm.Manual/Attributes/AttributesTest.cs
+++ b/Orm/Xtensive.Orm.Manual/Attributes/AttributesTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2009.12.11
 
-using System;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.IoC;
diff --git a/Orm/Xtensive.Orm.Manual/Caching/CalculatedValueCachingTest.cs b/Orm/Xtensive.Orm.Manual/Caching/CalculatedValueCachingTest.cs
index de7fb0978..e6da82de2 100644
--- a/Orm/Xtensive.Orm.Manual/Caching/CalculatedValueCachingTest.cs
+++ b/Orm/Xtensive.Orm.Manual/Caching/CalculatedValueCachingTest.cs
@@ -4,14 +4,11 @@
 // Created by: Alex Yakunin
 // Created:    2009.12.18
 
-using System;
 using System.Linq.Expressions;
-using System.Threading;
 using NUnit.Framework;
 using Xtensive.Caching;
 using Xtensive.Core;
 using Xtensive.Linq;
-using System.Linq;
 using Xtensive.Orm.Tests;
 
 namespace Xtensive.Orm.Manual.Caching
diff --git a/Orm/Xtensive.Orm.Manual/Concurrency/LockingTest.cs b/Orm/Xtensive.Orm.Manual/Concurrency/LockingTest.cs
index e41781fd2..a8b5cd841 100644
--- a/Orm/Xtensive.Orm.Manual/Concurrency/LockingTest.cs
+++ b/Orm/Xtensive.Orm.Manual/Concurrency/LockingTest.cs
@@ -4,9 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2009.11.11
 
-using System;
-using System.Linq;
-using System.Threading;
 using System.Transactions;
 using NUnit.Framework;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm.Manual/Concurrency/VersionsTest.cs b/Orm/Xtensive.Orm.Manual/Concurrency/VersionsTest.cs
index 2d02b09de..67a293887 100644
--- a/Orm/Xtensive.Orm.Manual/Concurrency/VersionsTest.cs
+++ b/Orm/Xtensive.Orm.Manual/Concurrency/VersionsTest.cs
@@ -4,9 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2009.11.11
 
-using System;
-using System.Linq;
-using System.Threading;
 using System.Transactions;
 using NUnit.Framework;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm.Manual/DomainAndSession/DomainAndSessionSample.cs b/Orm/Xtensive.Orm.Manual/DomainAndSession/DomainAndSessionSample.cs
index 3bbb4d37a..20eb409ab 100644
--- a/Orm/Xtensive.Orm.Manual/DomainAndSession/DomainAndSessionSample.cs
+++ b/Orm/Xtensive.Orm.Manual/DomainAndSession/DomainAndSessionSample.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Kofman
 // Created:    2009.06.17
 
-using System;
 using System.Transactions;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Manual/Entities/TestFixture.cs b/Orm/Xtensive.Orm.Manual/Entities/TestFixture.cs
index c9644a0f2..dcf695a20 100644
--- a/Orm/Xtensive.Orm.Manual/Entities/TestFixture.cs
+++ b/Orm/Xtensive.Orm.Manual/Entities/TestFixture.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Kofman
 // Created:    2009.06.25
 
-using System;
 using System.Diagnostics;
 using NUnit.Framework;
 using Xtensive.Orm.Tests;
diff --git a/Orm/Xtensive.Orm.Manual/EntitySets/EntitySetsTest.cs b/Orm/Xtensive.Orm.Manual/EntitySets/EntitySetsTest.cs
index 46f0be363..91d4bacd5 100644
--- a/Orm/Xtensive.Orm.Manual/EntitySets/EntitySetsTest.cs
+++ b/Orm/Xtensive.Orm.Manual/EntitySets/EntitySetsTest.cs
@@ -4,9 +4,6 @@
 // Created by: Alex Kofman
 // Created:    2009.06.29
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Tests;
 
diff --git a/Orm/Xtensive.Orm.Manual/FutureQueries/FutureQueriesTest.cs b/Orm/Xtensive.Orm.Manual/FutureQueries/FutureQueriesTest.cs
index 42ed15354..3f85ccb96 100644
--- a/Orm/Xtensive.Orm.Manual/FutureQueries/FutureQueriesTest.cs
+++ b/Orm/Xtensive.Orm.Manual/FutureQueries/FutureQueriesTest.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2009.12.31
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Orm.Tests;
diff --git a/Orm/Xtensive.Orm.Manual/Indexes/TestFixture.cs b/Orm/Xtensive.Orm.Manual/Indexes/TestFixture.cs
index 7ccbad81b..6a856a060 100644
--- a/Orm/Xtensive.Orm.Manual/Indexes/TestFixture.cs
+++ b/Orm/Xtensive.Orm.Manual/Indexes/TestFixture.cs
@@ -4,8 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2009.06.16
 
-using System;
-using System.Linq;
 using System.Linq.Expressions;
 using NUnit.Framework;
 using Xtensive.Orm.Tests;
diff --git a/Orm/Xtensive.Orm.Manual/Intro/CheatSheetTest.cs b/Orm/Xtensive.Orm.Manual/Intro/CheatSheetTest.cs
index 85be5a14a..4a8ac91ff 100644
--- a/Orm/Xtensive.Orm.Manual/Intro/CheatSheetTest.cs
+++ b/Orm/Xtensive.Orm.Manual/Intro/CheatSheetTest.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2009.12.23
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Tests;
 
diff --git a/Orm/Xtensive.Orm.Manual/Intro/HelloWorldTest.cs b/Orm/Xtensive.Orm.Manual/Intro/HelloWorldTest.cs
index 88124da74..6d8b346dd 100644
--- a/Orm/Xtensive.Orm.Manual/Intro/HelloWorldTest.cs
+++ b/Orm/Xtensive.Orm.Manual/Intro/HelloWorldTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2009.12.23
 
-using System;
 using System.Diagnostics;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Manual/Legacy/CustomKeyGenerators/CustomKeyGeneratorsTest.cs b/Orm/Xtensive.Orm.Manual/Legacy/CustomKeyGenerators/CustomKeyGeneratorsTest.cs
index 92ed2a2cc..989107cf7 100644
--- a/Orm/Xtensive.Orm.Manual/Legacy/CustomKeyGenerators/CustomKeyGeneratorsTest.cs
+++ b/Orm/Xtensive.Orm.Manual/Legacy/CustomKeyGenerators/CustomKeyGeneratorsTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2010.01.28
 
-using System;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Orm.Tests;
diff --git a/Orm/Xtensive.Orm.Manual/ModellingDomain/AuditAndOpenGenericsTest.cs b/Orm/Xtensive.Orm.Manual/ModellingDomain/AuditAndOpenGenericsTest.cs
index 1fae2689a..22f652ae2 100644
--- a/Orm/Xtensive.Orm.Manual/ModellingDomain/AuditAndOpenGenericsTest.cs
+++ b/Orm/Xtensive.Orm.Manual/ModellingDomain/AuditAndOpenGenericsTest.cs
@@ -4,9 +4,6 @@
 // Created by: Alex Kofman
 // Created:    2009.06.17
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Orm.Building;
diff --git a/Orm/Xtensive.Orm.Manual/ModellingDomain/IndexAttributeTest.cs b/Orm/Xtensive.Orm.Manual/ModellingDomain/IndexAttributeTest.cs
index a2ade42e3..71f140eb6 100644
--- a/Orm/Xtensive.Orm.Manual/ModellingDomain/IndexAttributeTest.cs
+++ b/Orm/Xtensive.Orm.Manual/ModellingDomain/IndexAttributeTest.cs
@@ -4,9 +4,6 @@
 // Created by: Alex Kofman
 // Created:    2009.06.17
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Tests;
 
diff --git a/Orm/Xtensive.Orm.Manual/Persistent/TestFixture.cs b/Orm/Xtensive.Orm.Manual/Persistent/TestFixture.cs
index 6abcefa0f..d0f5532c1 100644
--- a/Orm/Xtensive.Orm.Manual/Persistent/TestFixture.cs
+++ b/Orm/Xtensive.Orm.Manual/Persistent/TestFixture.cs
@@ -5,7 +5,6 @@
 // Created:    2009.06.24
 
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Tests;
 
diff --git a/Orm/Xtensive.Orm.Manual/Prefetch/PrefetchTest.cs b/Orm/Xtensive.Orm.Manual/Prefetch/PrefetchTest.cs
index 21d0d2977..3af44f078 100644
--- a/Orm/Xtensive.Orm.Manual/Prefetch/PrefetchTest.cs
+++ b/Orm/Xtensive.Orm.Manual/Prefetch/PrefetchTest.cs
@@ -4,10 +4,7 @@
 // Created by: Alex Yakunin
 // Created:    2009.12.24
 
-using System;
 using NUnit.Framework;
-using System.Linq;
-using System.Threading.Tasks;
 using Xtensive.Core;
 using Xtensive.Orm.Internals.Prefetch;
 using Xtensive.Orm.Services;
diff --git a/Orm/Xtensive.Orm.Manual/Services/DirectSqlAccessorTest.cs b/Orm/Xtensive.Orm.Manual/Services/DirectSqlAccessorTest.cs
index a5f0daf8f..79528638c 100644
--- a/Orm/Xtensive.Orm.Manual/Services/DirectSqlAccessorTest.cs
+++ b/Orm/Xtensive.Orm.Manual/Services/DirectSqlAccessorTest.cs
@@ -4,8 +4,6 @@
 // Created by: Alexander Nikolaev
 // Created:    2010.02.24
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Orm.Tests;
diff --git a/Orm/Xtensive.Orm.Manual/Services/DirectStateAccessorTest.cs b/Orm/Xtensive.Orm.Manual/Services/DirectStateAccessorTest.cs
index ff6c17d6e..f7955a45b 100644
--- a/Orm/Xtensive.Orm.Manual/Services/DirectStateAccessorTest.cs
+++ b/Orm/Xtensive.Orm.Manual/Services/DirectStateAccessorTest.cs
@@ -4,9 +4,7 @@
 // Created by: Alexander Nikolaev
 // Created:    2010.02.24
 
-using System;
 using System.Diagnostics;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Services;
 using Xtensive.Orm.Tests;
diff --git a/Orm/Xtensive.Orm.Manual/Structures/TestFixture.cs b/Orm/Xtensive.Orm.Manual/Structures/TestFixture.cs
index 615940817..590f410dd 100644
--- a/Orm/Xtensive.Orm.Manual/Structures/TestFixture.cs
+++ b/Orm/Xtensive.Orm.Manual/Structures/TestFixture.cs
@@ -4,8 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2009.06.16
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests;
diff --git a/Orm/Xtensive.Orm.Manual/Transactions/NestedTransactionsTest.cs b/Orm/Xtensive.Orm.Manual/Transactions/NestedTransactionsTest.cs
index 5e26b584b..bd8ec060f 100644
--- a/Orm/Xtensive.Orm.Manual/Transactions/NestedTransactionsTest.cs
+++ b/Orm/Xtensive.Orm.Manual/Transactions/NestedTransactionsTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2009.12.23
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Tests;
 using Xtensive.Orm;
diff --git a/Orm/Xtensive.Orm.Manual/Transactions/SessionSwitchingTest.cs b/Orm/Xtensive.Orm.Manual/Transactions/SessionSwitchingTest.cs
index 434654b50..85d049b70 100644
--- a/Orm/Xtensive.Orm.Manual/Transactions/SessionSwitchingTest.cs
+++ b/Orm/Xtensive.Orm.Manual/Transactions/SessionSwitchingTest.cs
@@ -4,11 +4,9 @@
 // Created by: Alexey Gamzov
 // Created:    2009.11.11
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Tests;
 using Xtensive.Orm.Configuration;
-using System.Linq;
 
 namespace Xtensive.Orm.Manual.Transactions.SessionSwitching
 {
diff --git a/Orm/Xtensive.Orm.Manual/Upgrade/Model_1/Model.cs b/Orm/Xtensive.Orm.Manual/Upgrade/Model_1/Model.cs
index adcbcee23..dcdaea04d 100644
--- a/Orm/Xtensive.Orm.Manual/Upgrade/Model_1/Model.cs
+++ b/Orm/Xtensive.Orm.Manual/Upgrade/Model_1/Model.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Kofman
 // Created:    2009.11.11
 
-using System;
 using System.Diagnostics;
 
 namespace Xtensive.Orm.Manual.Upgrade.Model_1
diff --git a/Orm/Xtensive.Orm.Manual/Upgrade/Model_2/Model.cs b/Orm/Xtensive.Orm.Manual/Upgrade/Model_2/Model.cs
index d05c6f9a7..28e525c5b 100644
--- a/Orm/Xtensive.Orm.Manual/Upgrade/Model_2/Model.cs
+++ b/Orm/Xtensive.Orm.Manual/Upgrade/Model_2/Model.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Kofman
 // Created:    2009.11.11
 
-using System;
 using System.Diagnostics;
 
 namespace Xtensive.Orm.Manual.Upgrade.Model_2
diff --git a/Orm/Xtensive.Orm.Manual/Upgrade/Model_2/Upgrader.cs b/Orm/Xtensive.Orm.Manual/Upgrade/Model_2/Upgrader.cs
index 6e1c80a36..f01d81012 100644
--- a/Orm/Xtensive.Orm.Manual/Upgrade/Model_2/Upgrader.cs
+++ b/Orm/Xtensive.Orm.Manual/Upgrade/Model_2/Upgrader.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Kofman
 // Created:    2009.11.12
 
-using System.Collections.Generic;
 using Xtensive.Orm.Upgrade;
 
 namespace Xtensive.Orm.Manual.Upgrade.Model_2
diff --git a/Orm/Xtensive.Orm.Manual/Upgrade/Model_3/Model.cs b/Orm/Xtensive.Orm.Manual/Upgrade/Model_3/Model.cs
index 478a26e70..559b938dd 100644
--- a/Orm/Xtensive.Orm.Manual/Upgrade/Model_3/Model.cs
+++ b/Orm/Xtensive.Orm.Manual/Upgrade/Model_3/Model.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Kofman
 // Created:    2009.11.12
 
-using System;
 
 namespace Xtensive.Orm.Manual.Upgrade.Model_3
 {
diff --git a/Orm/Xtensive.Orm.Manual/Upgrade/Model_3/Upgrader.cs b/Orm/Xtensive.Orm.Manual/Upgrade/Model_3/Upgrader.cs
index 9e603ef26..602d1b1f4 100644
--- a/Orm/Xtensive.Orm.Manual/Upgrade/Model_3/Upgrader.cs
+++ b/Orm/Xtensive.Orm.Manual/Upgrade/Model_3/Upgrader.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Kofman
 // Created:    2009.11.12
 
-using System.Collections.Generic;
 using Xtensive.Orm.Upgrade;
 
 namespace Xtensive.Orm.Manual.Upgrade.Model_3
diff --git a/Orm/Xtensive.Orm.Manual/Upgrade/Model_4/Model.cs b/Orm/Xtensive.Orm.Manual/Upgrade/Model_4/Model.cs
index ed00ca027..1ee575623 100644
--- a/Orm/Xtensive.Orm.Manual/Upgrade/Model_4/Model.cs
+++ b/Orm/Xtensive.Orm.Manual/Upgrade/Model_4/Model.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Kofman
 // Created:    2009.11.19
 
-using System;
 using Xtensive.Orm.Upgrade;
 
 namespace Xtensive.Orm.Manual.Upgrade.Model_4
diff --git a/Orm/Xtensive.Orm.Manual/Upgrade/Model_4/Upgrader.cs b/Orm/Xtensive.Orm.Manual/Upgrade/Model_4/Upgrader.cs
index 59ffba007..89c4fe0f1 100644
--- a/Orm/Xtensive.Orm.Manual/Upgrade/Model_4/Upgrader.cs
+++ b/Orm/Xtensive.Orm.Manual/Upgrade/Model_4/Upgrader.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Kofman
 // Created:    2009.11.19
 
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Orm.Upgrade;
 
 namespace Xtensive.Orm.Manual.Upgrade.Model_4
diff --git a/Orm/Xtensive.Orm.Manual/Upgrade/UpgradeHandlerEnabler.cs b/Orm/Xtensive.Orm.Manual/Upgrade/UpgradeHandlerEnabler.cs
index 60bb32206..b16d7333a 100644
--- a/Orm/Xtensive.Orm.Manual/Upgrade/UpgradeHandlerEnabler.cs
+++ b/Orm/Xtensive.Orm.Manual/Upgrade/UpgradeHandlerEnabler.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Kofman
 // Created:    2009.11.12
 
-using System;
 using System.Diagnostics;
 
 namespace Xtensive.Orm.Manual.Upgrade
diff --git a/Orm/Xtensive.Orm.Manual/Upgrade/UpgradeTest.cs b/Orm/Xtensive.Orm.Manual/Upgrade/UpgradeTest.cs
index 3ae4fe196..16f4c7151 100644
--- a/Orm/Xtensive.Orm.Manual/Upgrade/UpgradeTest.cs
+++ b/Orm/Xtensive.Orm.Manual/Upgrade/UpgradeTest.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Kofman
 // Created:    2009.11.11
 
-using System;
-using System.Linq;
 using System.Reflection;
 using NUnit.Framework;
 using Xtensive.Orm.Tests;
diff --git a/Orm/Xtensive.Orm.MySql/Sql.Drivers.MySql/Connection.cs b/Orm/Xtensive.Orm.MySql/Sql.Drivers.MySql/Connection.cs
index 4bb26e796..14239e3dc 100644
--- a/Orm/Xtensive.Orm.MySql/Sql.Drivers.MySql/Connection.cs
+++ b/Orm/Xtensive.Orm.MySql/Sql.Drivers.MySql/Connection.cs
@@ -7,8 +7,6 @@
 using System.Data;
 using System.Data.Common;
 using System.Security;
-using System.Threading;
-using System.Threading.Tasks;
 using MySql.Data.MySqlClient;
 
 namespace Xtensive.Sql.Drivers.MySql
diff --git a/Orm/Xtensive.Orm.MySql/Sql.Drivers.MySql/Driver.cs b/Orm/Xtensive.Orm.MySql/Sql.Drivers.MySql/Driver.cs
index 6b0bfe364..71f72d467 100644
--- a/Orm/Xtensive.Orm.MySql/Sql.Drivers.MySql/Driver.cs
+++ b/Orm/Xtensive.Orm.MySql/Sql.Drivers.MySql/Driver.cs
@@ -4,7 +4,6 @@
 // Created by: Malisa Ncube
 // Created:    2011.02.25
 
-using System;
 using System.Runtime.CompilerServices;
 using MySql.Data.MySqlClient;
 using Xtensive.Sql.Info;
diff --git a/Orm/Xtensive.Orm.MySql/Sql.Drivers.MySql/DriverFactory.cs b/Orm/Xtensive.Orm.MySql/Sql.Drivers.MySql/DriverFactory.cs
index 8be25beb3..4fd19060d 100644
--- a/Orm/Xtensive.Orm.MySql/Sql.Drivers.MySql/DriverFactory.cs
+++ b/Orm/Xtensive.Orm.MySql/Sql.Drivers.MySql/DriverFactory.cs
@@ -4,12 +4,8 @@
 // Created by: Malisa Ncube
 // Created:    2011.02.25
 
-using System;
 using System.Data.Common;
-using System.Linq;
 using System.Security;
-using System.Threading;
-using System.Threading.Tasks;
 using MySql.Data.MySqlClient;
 using Xtensive.Orm;
 using Xtensive.Sql.Drivers.MySql.Resources;
diff --git a/Orm/Xtensive.Orm.MySql/Sql.Drivers.MySql/Resources/Strings.Designer.cs b/Orm/Xtensive.Orm.MySql/Sql.Drivers.MySql/Resources/Strings.Designer.cs
index ecde49f5d..23de84229 100644
--- a/Orm/Xtensive.Orm.MySql/Sql.Drivers.MySql/Resources/Strings.Designer.cs
+++ b/Orm/Xtensive.Orm.MySql/Sql.Drivers.MySql/Resources/Strings.Designer.cs
@@ -9,7 +9,6 @@
 //------------------------------------------------------------------------------
 
 namespace Xtensive.Sql.Drivers.MySql.Resources {
-    using System;
     
     
     /// <summary>
diff --git a/Orm/Xtensive.Orm.MySql/Sql.Drivers.MySql/v5_0/Compiler.cs b/Orm/Xtensive.Orm.MySql/Sql.Drivers.MySql/v5_0/Compiler.cs
index 0a6628458..8d210dd31 100644
--- a/Orm/Xtensive.Orm.MySql/Sql.Drivers.MySql/v5_0/Compiler.cs
+++ b/Orm/Xtensive.Orm.MySql/Sql.Drivers.MySql/v5_0/Compiler.cs
@@ -4,13 +4,11 @@
 // Created by: Malisa Ncube
 // Created:    2011.02.25
 
-using System;
 using Xtensive.Sql.Compiler;
 using Xtensive.Sql.Ddl;
 using Xtensive.Sql.Dml;
 using Xtensive.Sql.Model;
 using Xtensive.Core;
-using System.Collections.Generic;
 
 namespace Xtensive.Sql.Drivers.MySql.v5_0
 {
diff --git a/Orm/Xtensive.Orm.MySql/Sql.Drivers.MySql/v5_0/Extractor.cs b/Orm/Xtensive.Orm.MySql/Sql.Drivers.MySql/v5_0/Extractor.cs
index 72d5fb55a..3f8df8183 100644
--- a/Orm/Xtensive.Orm.MySql/Sql.Drivers.MySql/v5_0/Extractor.cs
+++ b/Orm/Xtensive.Orm.MySql/Sql.Drivers.MySql/v5_0/Extractor.cs
@@ -4,12 +4,8 @@
 // Created by: Malisa Ncube
 // Created:    2011.02.25
 
-using System;
-using System.Collections.Generic;
 using System.Data;
 using System.Data.Common;
-using System.Threading;
-using System.Threading.Tasks;
 using Xtensive.Sql.Drivers.MySql.Resources;
 using Xtensive.Sql.Model;
 using Index = Xtensive.Sql.Model.Index;
diff --git a/Orm/Xtensive.Orm.MySql/Sql.Drivers.MySql/v5_0/ServiceInfoProvider.cs b/Orm/Xtensive.Orm.MySql/Sql.Drivers.MySql/v5_0/ServiceInfoProvider.cs
index 4169c8729..3a8e0352e 100644
--- a/Orm/Xtensive.Orm.MySql/Sql.Drivers.MySql/v5_0/ServiceInfoProvider.cs
+++ b/Orm/Xtensive.Orm.MySql/Sql.Drivers.MySql/v5_0/ServiceInfoProvider.cs
@@ -4,7 +4,6 @@
 // Created by: Malisa Ncube
 // Created:    2011.02.25
 
-using System;
 using Xtensive.Sql.Info;
 
 namespace Xtensive.Sql.Drivers.MySql.v5_0
diff --git a/Orm/Xtensive.Orm.MySql/Sql.Drivers.MySql/v5_0/Translator.cs b/Orm/Xtensive.Orm.MySql/Sql.Drivers.MySql/v5_0/Translator.cs
index 8675b2e56..19296b2a9 100644
--- a/Orm/Xtensive.Orm.MySql/Sql.Drivers.MySql/v5_0/Translator.cs
+++ b/Orm/Xtensive.Orm.MySql/Sql.Drivers.MySql/v5_0/Translator.cs
@@ -4,10 +4,7 @@
 // Created by: Malisa Ncube
 // Created:    2011.02.25
 
-using System;
-using System.Collections.Generic;
 using System.Diagnostics;
-using System.Linq;
 using System.Text;
 using Xtensive.Core;
 using Xtensive.Sql.Compiler;
diff --git a/Orm/Xtensive.Orm.MySql/Sql.Drivers.MySql/v5_0/TypeMapper.cs b/Orm/Xtensive.Orm.MySql/Sql.Drivers.MySql/v5_0/TypeMapper.cs
index 7100406a7..5016ab571 100644
--- a/Orm/Xtensive.Orm.MySql/Sql.Drivers.MySql/v5_0/TypeMapper.cs
+++ b/Orm/Xtensive.Orm.MySql/Sql.Drivers.MySql/v5_0/TypeMapper.cs
@@ -4,10 +4,8 @@
 // Created by: Malisa Ncube
 // Created:    2011.02.25
 
-using System;
 using System.Data;
 using System.Data.Common;
-using System.Linq;
 using System.Security;
 
 namespace Xtensive.Sql.Drivers.MySql.v5_0
diff --git a/Orm/Xtensive.Orm.MySql/Sql.Drivers.MySql/v5_6/Compiler.cs b/Orm/Xtensive.Orm.MySql/Sql.Drivers.MySql/v5_6/Compiler.cs
index eb3f10bde..205609785 100644
--- a/Orm/Xtensive.Orm.MySql/Sql.Drivers.MySql/v5_6/Compiler.cs
+++ b/Orm/Xtensive.Orm.MySql/Sql.Drivers.MySql/v5_6/Compiler.cs
@@ -4,8 +4,6 @@
 // Created by: Alena Mikshina
 // Created:    2013.12.30
 
-using System;
-using System.Collections.Generic;
 using Xtensive.Sql.Dml;
 
 namespace Xtensive.Sql.Drivers.MySql.v5_6
diff --git a/Orm/Xtensive.Orm.MySql/Sql.Drivers.MySql/v5_6/Translator.cs b/Orm/Xtensive.Orm.MySql/Sql.Drivers.MySql/v5_6/Translator.cs
index b61d85ac0..88781a54f 100644
--- a/Orm/Xtensive.Orm.MySql/Sql.Drivers.MySql/v5_6/Translator.cs
+++ b/Orm/Xtensive.Orm.MySql/Sql.Drivers.MySql/v5_6/Translator.cs
@@ -4,7 +4,6 @@
 // Created by: Alena Mikshina
 // Created:    2013.12.30
 
-using System;
 using Xtensive.Sql.Compiler;
 using Xtensive.Sql.Dml;
 
diff --git a/Orm/Xtensive.Orm.MySql/Sql.Drivers.MySql/v5_7/Translator.cs b/Orm/Xtensive.Orm.MySql/Sql.Drivers.MySql/v5_7/Translator.cs
index 9ea62b674..38960f641 100644
--- a/Orm/Xtensive.Orm.MySql/Sql.Drivers.MySql/v5_7/Translator.cs
+++ b/Orm/Xtensive.Orm.MySql/Sql.Drivers.MySql/v5_7/Translator.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2022.02.03
 
-using System;
 using Xtensive.Sql.Compiler;
 using Xtensive.Sql.Dml;
 
diff --git a/Orm/Xtensive.Orm.MySql/Sql.Drivers.MySql/v8_0/Translator.cs b/Orm/Xtensive.Orm.MySql/Sql.Drivers.MySql/v8_0/Translator.cs
index e69cd1edb..92338a3bc 100644
--- a/Orm/Xtensive.Orm.MySql/Sql.Drivers.MySql/v8_0/Translator.cs
+++ b/Orm/Xtensive.Orm.MySql/Sql.Drivers.MySql/v8_0/Translator.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2022.02.03
 
-using System;
 using Xtensive.Sql.Compiler;
 using Xtensive.Sql.Dml;
 
diff --git a/Orm/Xtensive.Orm.Oracle/Orm.Providers.Oracle/SqlCompiler.cs b/Orm/Xtensive.Orm.Oracle/Orm.Providers.Oracle/SqlCompiler.cs
index 7026269c6..ed2e00023 100644
--- a/Orm/Xtensive.Orm.Oracle/Orm.Providers.Oracle/SqlCompiler.cs
+++ b/Orm/Xtensive.Orm.Oracle/Orm.Providers.Oracle/SqlCompiler.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.08.07
 
-using System;
-using System.Collections.Generic;
 using Xtensive.Orm.Rse;
 using Xtensive.Orm.Rse.Compilation;
 using Xtensive.Sql;
diff --git a/Orm/Xtensive.Orm.Oracle/Sql.Drivers.Oracle/Driver.cs b/Orm/Xtensive.Orm.Oracle/Sql.Drivers.Oracle/Driver.cs
index 14c2440e5..385d4d9c3 100644
--- a/Orm/Xtensive.Orm.Oracle/Sql.Drivers.Oracle/Driver.cs
+++ b/Orm/Xtensive.Orm.Oracle/Sql.Drivers.Oracle/Driver.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.07.17
 
-using System;
 using Oracle.ManagedDataAccess.Client;
 using Xtensive.Sql.Info;
 
diff --git a/Orm/Xtensive.Orm.Oracle/Sql.Drivers.Oracle/DriverFactory.cs b/Orm/Xtensive.Orm.Oracle/Sql.Drivers.Oracle/DriverFactory.cs
index f01e74c4d..f570e073f 100644
--- a/Orm/Xtensive.Orm.Oracle/Sql.Drivers.Oracle/DriverFactory.cs
+++ b/Orm/Xtensive.Orm.Oracle/Sql.Drivers.Oracle/DriverFactory.cs
@@ -4,11 +4,7 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.07.16
 
-using System;
 using System.Data.Common;
-using System.Linq;
-using System.Threading;
-using System.Threading.Tasks;
 using Oracle.ManagedDataAccess.Client;
 using Xtensive.Core;
 using Xtensive.Orm;
diff --git a/Orm/Xtensive.Orm.Oracle/Sql.Drivers.Oracle/Resources/Strings.Designer.cs b/Orm/Xtensive.Orm.Oracle/Sql.Drivers.Oracle/Resources/Strings.Designer.cs
index 4464196c8..8551ac049 100644
--- a/Orm/Xtensive.Orm.Oracle/Sql.Drivers.Oracle/Resources/Strings.Designer.cs
+++ b/Orm/Xtensive.Orm.Oracle/Sql.Drivers.Oracle/Resources/Strings.Designer.cs
@@ -9,7 +9,6 @@
 //------------------------------------------------------------------------------
 
 namespace Xtensive.Sql.Drivers.Oracle.Resources {
-    using System;
     
     
     /// <summary>
diff --git a/Orm/Xtensive.Orm.Oracle/Sql.Drivers.Oracle/v09/Compiler.cs b/Orm/Xtensive.Orm.Oracle/Sql.Drivers.Oracle/v09/Compiler.cs
index c1799d229..6b2db93df 100644
--- a/Orm/Xtensive.Orm.Oracle/Sql.Drivers.Oracle/v09/Compiler.cs
+++ b/Orm/Xtensive.Orm.Oracle/Sql.Drivers.Oracle/v09/Compiler.cs
@@ -4,14 +4,12 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.07.17
 
-using System;
 using Xtensive.Core;
 using Xtensive.Sql.Compiler;
 using Xtensive.Sql.Ddl;
 using Xtensive.Sql.Dml;
 using Xtensive.Sql.Model;
 using Xtensive.Sql.Drivers.Oracle.Resources;
-using System.Collections.Generic;
 
 namespace Xtensive.Sql.Drivers.Oracle.v09
 {
diff --git a/Orm/Xtensive.Orm.Oracle/Sql.Drivers.Oracle/v09/Driver.cs b/Orm/Xtensive.Orm.Oracle/Sql.Drivers.Oracle/v09/Driver.cs
index a6f500479..a44b8f8b8 100644
--- a/Orm/Xtensive.Orm.Oracle/Sql.Drivers.Oracle/v09/Driver.cs
+++ b/Orm/Xtensive.Orm.Oracle/Sql.Drivers.Oracle/v09/Driver.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.07.17
 
-using System;
 using Xtensive.Sql.Compiler;
 using Xtensive.Sql.Info;
 
diff --git a/Orm/Xtensive.Orm.Oracle/Sql.Drivers.Oracle/v09/Extractor.cs b/Orm/Xtensive.Orm.Oracle/Sql.Drivers.Oracle/v09/Extractor.cs
index 3dd581b8a..bd0a4d292 100644
--- a/Orm/Xtensive.Orm.Oracle/Sql.Drivers.Oracle/v09/Extractor.cs
+++ b/Orm/Xtensive.Orm.Oracle/Sql.Drivers.Oracle/v09/Extractor.cs
@@ -4,13 +4,8 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.07.17
 
-using System;
-using System.Collections.Generic;
 using System.Data;
 using System.Data.Common;
-using System.Linq;
-using System.Threading;
-using System.Threading.Tasks;
 using Oracle.ManagedDataAccess.Client;
 using Xtensive.Sql.Model;
 using Xtensive.Sql.Drivers.Oracle.Resources;
diff --git a/Orm/Xtensive.Orm.Oracle/Sql.Drivers.Oracle/v09/ServerInfoProvider.cs b/Orm/Xtensive.Orm.Oracle/Sql.Drivers.Oracle/v09/ServerInfoProvider.cs
index 15206f6fb..bbc7c7ef1 100644
--- a/Orm/Xtensive.Orm.Oracle/Sql.Drivers.Oracle/v09/ServerInfoProvider.cs
+++ b/Orm/Xtensive.Orm.Oracle/Sql.Drivers.Oracle/v09/ServerInfoProvider.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.07.17
 
-using System;
 using Oracle.ManagedDataAccess.Client;
 using Xtensive.Sql.Info;
 
diff --git a/Orm/Xtensive.Orm.Oracle/Sql.Drivers.Oracle/v09/Translator.cs b/Orm/Xtensive.Orm.Oracle/Sql.Drivers.Oracle/v09/Translator.cs
index 25bc665d5..fe4b5dc4a 100644
--- a/Orm/Xtensive.Orm.Oracle/Sql.Drivers.Oracle/v09/Translator.cs
+++ b/Orm/Xtensive.Orm.Oracle/Sql.Drivers.Oracle/v09/Translator.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.07.17
 
-using System;
 using System.Text;
 using Xtensive.Core;
 using Xtensive.Sql.Compiler;
diff --git a/Orm/Xtensive.Orm.Oracle/Sql.Drivers.Oracle/v09/TypeMapper.cs b/Orm/Xtensive.Orm.Oracle/Sql.Drivers.Oracle/v09/TypeMapper.cs
index f50fc821a..ca53b9b8b 100644
--- a/Orm/Xtensive.Orm.Oracle/Sql.Drivers.Oracle/v09/TypeMapper.cs
+++ b/Orm/Xtensive.Orm.Oracle/Sql.Drivers.Oracle/v09/TypeMapper.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.07.17
 
-using System;
 using System.Data;
 using System.Data.Common;
 using Oracle.ManagedDataAccess.Client;
diff --git a/Orm/Xtensive.Orm.Oracle/Sql.Drivers.Oracle/v10/Compiler.cs b/Orm/Xtensive.Orm.Oracle/Sql.Drivers.Oracle/v10/Compiler.cs
index c9f2c54fe..0d855b2b8 100644
--- a/Orm/Xtensive.Orm.Oracle/Sql.Drivers.Oracle/v10/Compiler.cs
+++ b/Orm/Xtensive.Orm.Oracle/Sql.Drivers.Oracle/v10/Compiler.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.07.17
 
-using System;
 using System.Diagnostics;
 using Xtensive.Sql.Compiler;
 
diff --git a/Orm/Xtensive.Orm.Oracle/Sql.Drivers.Oracle/v10/Extractor.cs b/Orm/Xtensive.Orm.Oracle/Sql.Drivers.Oracle/v10/Extractor.cs
index 1d7eab508..cd8c166a5 100644
--- a/Orm/Xtensive.Orm.Oracle/Sql.Drivers.Oracle/v10/Extractor.cs
+++ b/Orm/Xtensive.Orm.Oracle/Sql.Drivers.Oracle/v10/Extractor.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.07.17
 
-using System.Collections.Generic;
 
 namespace Xtensive.Sql.Drivers.Oracle.v10
 {
diff --git a/Orm/Xtensive.Orm.Oracle/Sql.Drivers.Oracle/v10/Translator.cs b/Orm/Xtensive.Orm.Oracle/Sql.Drivers.Oracle/v10/Translator.cs
index 50e0d6714..bf5d896ef 100644
--- a/Orm/Xtensive.Orm.Oracle/Sql.Drivers.Oracle/v10/Translator.cs
+++ b/Orm/Xtensive.Orm.Oracle/Sql.Drivers.Oracle/v10/Translator.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.07.17
 
-using System;
 using Xtensive.Sql.Compiler;
 
 namespace Xtensive.Sql.Drivers.Oracle.v10
diff --git a/Orm/Xtensive.Orm.Oracle/Sql.Drivers.Oracle/v10/TypeMapper.cs b/Orm/Xtensive.Orm.Oracle/Sql.Drivers.Oracle/v10/TypeMapper.cs
index ec9302137..722f72138 100644
--- a/Orm/Xtensive.Orm.Oracle/Sql.Drivers.Oracle/v10/TypeMapper.cs
+++ b/Orm/Xtensive.Orm.Oracle/Sql.Drivers.Oracle/v10/TypeMapper.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2010.02.18
 
-using System;
 using System.Data.Common;
 using System.Diagnostics;
 using Oracle.ManagedDataAccess.Client;
diff --git a/Orm/Xtensive.Orm.Oracle/Sql.Drivers.Oracle/v11/Compiler.cs b/Orm/Xtensive.Orm.Oracle/Sql.Drivers.Oracle/v11/Compiler.cs
index a06eba02f..bb8eff8bf 100644
--- a/Orm/Xtensive.Orm.Oracle/Sql.Drivers.Oracle/v11/Compiler.cs
+++ b/Orm/Xtensive.Orm.Oracle/Sql.Drivers.Oracle/v11/Compiler.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.07.17
 
-using System;
 using System.Diagnostics;
 using Xtensive.Sql.Compiler;
 
diff --git a/Orm/Xtensive.Orm.Oracle/Sql.Drivers.Oracle/v11/Extractor.cs b/Orm/Xtensive.Orm.Oracle/Sql.Drivers.Oracle/v11/Extractor.cs
index 79ae90d7d..17baa1b98 100644
--- a/Orm/Xtensive.Orm.Oracle/Sql.Drivers.Oracle/v11/Extractor.cs
+++ b/Orm/Xtensive.Orm.Oracle/Sql.Drivers.Oracle/v11/Extractor.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.07.17
 
-using System;
 using Xtensive.Sql.Model;
 
 namespace Xtensive.Sql.Drivers.Oracle.v11
diff --git a/Orm/Xtensive.Orm.Oracle/Sql.Drivers.Oracle/v11/Translator.cs b/Orm/Xtensive.Orm.Oracle/Sql.Drivers.Oracle/v11/Translator.cs
index 67c9a80be..cf6368588 100644
--- a/Orm/Xtensive.Orm.Oracle/Sql.Drivers.Oracle/v11/Translator.cs
+++ b/Orm/Xtensive.Orm.Oracle/Sql.Drivers.Oracle/v11/Translator.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.07.17
 
-using System;
 using Xtensive.Sql.Compiler;
 using Xtensive.Sql.Ddl;
 using Xtensive.Sql.Dml;
diff --git a/Orm/Xtensive.Orm.Oracle/Sql.Drivers.Oracle/v11/TypeMapper.cs b/Orm/Xtensive.Orm.Oracle/Sql.Drivers.Oracle/v11/TypeMapper.cs
index 61e39d250..7f507caab 100644
--- a/Orm/Xtensive.Orm.Oracle/Sql.Drivers.Oracle/v11/TypeMapper.cs
+++ b/Orm/Xtensive.Orm.Oracle/Sql.Drivers.Oracle/v11/TypeMapper.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2010.02.18
 
-using System;
 using System.Diagnostics;
 
 namespace Xtensive.Sql.Drivers.Oracle.v11
diff --git a/Orm/Xtensive.Orm.PostgreSql/Orm.Providers.PostgreSql/DomainHandler.cs b/Orm/Xtensive.Orm.PostgreSql/Orm.Providers.PostgreSql/DomainHandler.cs
index 27945b097..61b3085d7 100644
--- a/Orm/Xtensive.Orm.PostgreSql/Orm.Providers.PostgreSql/DomainHandler.cs
+++ b/Orm/Xtensive.Orm.PostgreSql/Orm.Providers.PostgreSql/DomainHandler.cs
@@ -4,9 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2008.07.04
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Core;
 using Xtensive.Orm.Rse.Compilation;
 
diff --git a/Orm/Xtensive.Orm.PostgreSql/Orm.Providers.PostgreSql/SqlCompiler.cs b/Orm/Xtensive.Orm.PostgreSql/Orm.Providers.PostgreSql/SqlCompiler.cs
index 05e8c584d..88a64ab36 100644
--- a/Orm/Xtensive.Orm.PostgreSql/Orm.Providers.PostgreSql/SqlCompiler.cs
+++ b/Orm/Xtensive.Orm.PostgreSql/Orm.Providers.PostgreSql/SqlCompiler.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.04.27
 
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Core;
 using Xtensive.Orm.Rse;
 using Xtensive.Orm.Rse.Compilation;
diff --git a/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/Connection.cs b/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/Connection.cs
index 6d8e8cccf..0bde52419 100644
--- a/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/Connection.cs
+++ b/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/Connection.cs
@@ -8,8 +8,6 @@
 using Npgsql;
 using System.Data;
 using System.Data.Common;
-using System.Threading;
-using System.Threading.Tasks;
 
 namespace Xtensive.Sql.Drivers.PostgreSql
 {
diff --git a/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/Driver.cs b/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/Driver.cs
index 63d93ce21..3f08201e5 100644
--- a/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/Driver.cs
+++ b/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/Driver.cs
@@ -2,7 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
 using System.IO;
 using System.Net.Sockets;
 using System.Security;
diff --git a/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/DriverFactory.cs b/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/DriverFactory.cs
index bf4db22e5..ea7517e39 100644
--- a/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/DriverFactory.cs
+++ b/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/DriverFactory.cs
@@ -4,11 +4,8 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.06.23
 
-using System;
 using System.Data.Common;
 using System.Security;
-using System.Threading;
-using System.Threading.Tasks;
 using Npgsql;
 using Xtensive.Orm;
 using Xtensive.Sql.Info;
diff --git a/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/PostgreSqlTypeMapper.cs b/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/PostgreSqlTypeMapper.cs
index e41eba8e6..85ccb8211 100644
--- a/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/PostgreSqlTypeMapper.cs
+++ b/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/PostgreSqlTypeMapper.cs
@@ -4,7 +4,6 @@
 // Created by: Alena Mikshina
 // Created:    2014.04.09
 
-using System;
 using System.Data.Common;
 using Npgsql;
 using NpgsqlTypes;
diff --git a/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/Resources/Strings.Designer.cs b/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/Resources/Strings.Designer.cs
index 5e3755393..10c2249b3 100644
--- a/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/Resources/Strings.Designer.cs
+++ b/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/Resources/Strings.Designer.cs
@@ -9,7 +9,6 @@
 //------------------------------------------------------------------------------
 
 namespace Xtensive.Sql.Drivers.PostgreSql.Resources {
-    using System;
     
     
     /// <summary>
diff --git a/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v10_0/Compiler.cs b/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v10_0/Compiler.cs
index aed1c3dee..8efe2019e 100644
--- a/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v10_0/Compiler.cs
+++ b/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v10_0/Compiler.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2019.09.25
 
-using System;
-using System.Collections.Generic;
 using Xtensive.Sql.Dml;
 
 namespace Xtensive.Sql.Drivers.PostgreSql.v10_0
diff --git a/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v10_0/Extractor.cs b/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v10_0/Extractor.cs
index 57412aeb1..d1910eacf 100644
--- a/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v10_0/Extractor.cs
+++ b/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v10_0/Extractor.cs
@@ -4,11 +4,7 @@
 // Created by: Alexey Kulakov
 // Created:    2019.09.25
 
-using System;
-using System.Collections.Generic;
 using System.Data.Common;
-using System.Threading;
-using System.Threading.Tasks;
 using Xtensive.Core;
 using Xtensive.Sql.Dml;
 using Xtensive.Sql.Model;
diff --git a/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v10_0/Translator.cs b/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v10_0/Translator.cs
index 5abb3f0dc..7208dbc9e 100644
--- a/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v10_0/Translator.cs
+++ b/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v10_0/Translator.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2019.09.25
 
-using System;
 using Xtensive.Sql.Compiler;
 using Xtensive.Sql.Dml;
 
diff --git a/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_0/Compiler.cs b/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_0/Compiler.cs
index 8b723edd8..17f50bfef 100644
--- a/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_0/Compiler.cs
+++ b/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_0/Compiler.cs
@@ -2,9 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Orm.Providers.PostgreSql;
 using Xtensive.Sql.Compiler;
 using Xtensive.Sql.Dml;
diff --git a/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_0/Driver.cs b/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_0/Driver.cs
index bf1e7874f..6eaba6c1b 100644
--- a/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_0/Driver.cs
+++ b/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_0/Driver.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.06.23
 
-using System;
 using NpgsqlTypes;
 using Xtensive.Reflection.PostgreSql;
 using Xtensive.Sql.Compiler;
diff --git a/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_0/Extractor.cs b/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_0/Extractor.cs
index 34a0b709a..5b9e77642 100644
--- a/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_0/Extractor.cs
+++ b/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_0/Extractor.cs
@@ -2,9 +2,7 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
 using System.Collections.Concurrent;
-using System.Collections.Generic;
 using System.Data.Common;
 using System.Diagnostics;
 using System.Text;
@@ -12,9 +10,6 @@
 using Xtensive.Core;
 using Xtensive.Sql.Model;
 using Xtensive.Sql.Dml;
-using System.Linq;
-using System.Threading;
-using System.Threading.Tasks;
 using Index = Xtensive.Sql.Model.Index;
 
 namespace Xtensive.Sql.Drivers.PostgreSql.v8_0
diff --git a/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_0/PathMapper.cs b/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_0/PathMapper.cs
index 0ae1f821e..9eb825d7f 100644
--- a/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_0/PathMapper.cs
+++ b/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_0/PathMapper.cs
@@ -4,7 +4,6 @@
 // Created by: Alena Mikshina
 // Created:    2014.04.10
 
-using System;
 using System.Data.Common;
 using Npgsql;
 using NpgsqlTypes;
diff --git a/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_0/PolygonMapper.cs b/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_0/PolygonMapper.cs
index 6b25c1977..eb6269549 100644
--- a/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_0/PolygonMapper.cs
+++ b/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_0/PolygonMapper.cs
@@ -4,7 +4,6 @@
 // Created by: Alena Mikshina
 // Created:    2014.04.10
 
-using System;
 using System.Data.Common;
 using Npgsql;
 using NpgsqlTypes;
diff --git a/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_0/ServerInfoProvider.cs b/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_0/ServerInfoProvider.cs
index 62c22b521..81544ff84 100644
--- a/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_0/ServerInfoProvider.cs
+++ b/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_0/ServerInfoProvider.cs
@@ -2,7 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
 using Xtensive.Sql.Info;
 
 namespace Xtensive.Sql.Drivers.PostgreSql.v8_0
diff --git a/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_0/Translator.cs b/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_0/Translator.cs
index 322509933..b54678b3e 100644
--- a/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_0/Translator.cs
+++ b/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_0/Translator.cs
@@ -2,7 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
 using System.Diagnostics;
 using System.Text;
 using NpgsqlTypes;
diff --git a/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_0/TypeMapper.cs b/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_0/TypeMapper.cs
index 4e419085d..f372cf6b1 100644
--- a/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_0/TypeMapper.cs
+++ b/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_0/TypeMapper.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.06.23
 
-using System;
 using System.Data;
 using System.Data.Common;
 using System.Security;
diff --git a/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_1/Driver.cs b/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_1/Driver.cs
index 082752b95..8e6624afa 100644
--- a/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_1/Driver.cs
+++ b/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_1/Driver.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.06.23
 
-using System;
 using Npgsql;
 using Xtensive.Sql.Compiler;
 using Xtensive.Sql.Info;
diff --git a/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_1/Translator.cs b/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_1/Translator.cs
index 297223518..2ed355952 100644
--- a/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_1/Translator.cs
+++ b/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_1/Translator.cs
@@ -2,7 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
 using Xtensive.Sql.Compiler;
 using Xtensive.Sql.Dml;
 
diff --git a/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_1/TypeMapper.cs b/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_1/TypeMapper.cs
index 9be3f9472..c965ced81 100644
--- a/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_1/TypeMapper.cs
+++ b/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_1/TypeMapper.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.06.23
 
-using System;
 
 namespace Xtensive.Sql.Drivers.PostgreSql.v8_1
 {
diff --git a/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_2/Compiler.cs b/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_2/Compiler.cs
index 68496eca6..0b063fc1a 100644
--- a/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_2/Compiler.cs
+++ b/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_2/Compiler.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.06.23
 
-using System;
 using System.Diagnostics;
 
 namespace Xtensive.Sql.Drivers.PostgreSql.v8_2
diff --git a/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_2/Driver.cs b/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_2/Driver.cs
index ba36f2e06..f938597da 100644
--- a/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_2/Driver.cs
+++ b/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_2/Driver.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.06.23
 
-using System;
 using Npgsql;
 using Xtensive.Sql.Compiler;
 using Xtensive.Sql.Info;
diff --git a/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_2/Extractor.cs b/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_2/Extractor.cs
index 192766a9f..dff328545 100644
--- a/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_2/Extractor.cs
+++ b/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_2/Extractor.cs
@@ -2,7 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
 using System.Data.Common;
 using Xtensive.Sql.Dml;
 using Xtensive.Sql.Model;
diff --git a/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_2/Translator.cs b/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_2/Translator.cs
index e648b6e2d..39cbd9087 100644
--- a/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_2/Translator.cs
+++ b/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_2/Translator.cs
@@ -7,6 +7,7 @@
 using Xtensive.Sql.Dml;
 using Xtensive.Sql.Model;
 using Xtensive.Sql.Compiler;
+using Index = Xtensive.Sql.Model.Index;
 
 namespace Xtensive.Sql.Drivers.PostgreSql.v8_2
 {
diff --git a/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_2/TypeMapper.cs b/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_2/TypeMapper.cs
index 987922dc2..9f21d9751 100644
--- a/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_2/TypeMapper.cs
+++ b/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_2/TypeMapper.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.06.23
 
-using System;
 
 namespace Xtensive.Sql.Drivers.PostgreSql.v8_2
 {
diff --git a/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_3/Compiler.cs b/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_3/Compiler.cs
index f5c3cabe0..8801b2b79 100644
--- a/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_3/Compiler.cs
+++ b/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_3/Compiler.cs
@@ -4,9 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.06.23
 
-using System;
-using System.Linq;
-using System.Collections.Generic;
 using System.Diagnostics;
 using System.Text;
 using Xtensive.Sql.Compiler;
diff --git a/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_3/Driver.cs b/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_3/Driver.cs
index 603d96536..ec2cc0b1b 100644
--- a/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_3/Driver.cs
+++ b/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_3/Driver.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.06.23
 
-using System;
 using Npgsql;
 using Xtensive.Sql.Compiler;
 using Xtensive.Sql.Info;
diff --git a/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_3/Translator.cs b/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_3/Translator.cs
index fb0fe8279..0ad65c723 100644
--- a/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_3/Translator.cs
+++ b/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_3/Translator.cs
@@ -2,13 +2,11 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
 using System.Text;
 using Xtensive.Sql.Compiler;
 using Xtensive.Sql.Ddl;
 using Xtensive.Sql.Dml;
 using Xtensive.Sql.Model;
-using System.Linq;
 using Xtensive.Reflection.PostgreSql;
 
 namespace Xtensive.Sql.Drivers.PostgreSql.v8_3
diff --git a/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_3/TypeMapper.cs b/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_3/TypeMapper.cs
index 41c200e1b..4837a766c 100644
--- a/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_3/TypeMapper.cs
+++ b/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_3/TypeMapper.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.06.23
 
-using System;
 using System.Data;
 using System.Data.Common;
 
diff --git a/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_4/Extractor.cs b/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_4/Extractor.cs
index 4b7c54246..a5a6bd0b2 100644
--- a/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_4/Extractor.cs
+++ b/Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v8_4/Extractor.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Kryuchkov
 // Created:    2009.07.07
 
-using System;
 using System.Data.Common;
 
 namespace Xtensive.Sql.Drivers.PostgreSql.v8_4
diff --git a/Orm/Xtensive.Orm.PostgreSql/WellKnownTypes.cs b/Orm/Xtensive.Orm.PostgreSql/WellKnownTypes.cs
index 58c927fd7..88d19c0c0 100644
--- a/Orm/Xtensive.Orm.PostgreSql/WellKnownTypes.cs
+++ b/Orm/Xtensive.Orm.PostgreSql/WellKnownTypes.cs
@@ -2,8 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Collections.Generic;
 using System.Text;
 using NpgsqlTypes;
 
diff --git a/Orm/Xtensive.Orm.SqlServer/Orm.Providers.SqlServer/DomainHandler.cs b/Orm/Xtensive.Orm.SqlServer/Orm.Providers.SqlServer/DomainHandler.cs
index 30a34371e..7fe84d205 100644
--- a/Orm/Xtensive.Orm.SqlServer/Orm.Providers.SqlServer/DomainHandler.cs
+++ b/Orm/Xtensive.Orm.SqlServer/Orm.Providers.SqlServer/DomainHandler.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2008.07.04
 
-using System;
-using System.Collections.Generic;
 using Xtensive.Core;
 using Xtensive.Orm.Rse.Compilation;
 
diff --git a/Orm/Xtensive.Orm.SqlServer/Orm.Providers.SqlServer/SearchConditionCompilerV09.cs b/Orm/Xtensive.Orm.SqlServer/Orm.Providers.SqlServer/SearchConditionCompilerV09.cs
index 2f2983fe4..feefba969 100644
--- a/Orm/Xtensive.Orm.SqlServer/Orm.Providers.SqlServer/SearchConditionCompilerV09.cs
+++ b/Orm/Xtensive.Orm.SqlServer/Orm.Providers.SqlServer/SearchConditionCompilerV09.cs
@@ -4,9 +4,7 @@
 // Created by: Alexey Kulakov
 // Created:    2016.12.08
 
-using System;
 using System.Globalization;
-using System.Linq;
 using System.Text;
 using Xtensive.Orm.FullTextSearchCondition;
 using Xtensive.Orm.FullTextSearchCondition.Interfaces;
diff --git a/Orm/Xtensive.Orm.SqlServer/Orm.Providers.SqlServer/SqlCompiler.cs b/Orm/Xtensive.Orm.SqlServer/Orm.Providers.SqlServer/SqlCompiler.cs
index 3f332d0c4..c769b5e74 100644
--- a/Orm/Xtensive.Orm.SqlServer/Orm.Providers.SqlServer/SqlCompiler.cs
+++ b/Orm/Xtensive.Orm.SqlServer/Orm.Providers.SqlServer/SqlCompiler.cs
@@ -4,9 +4,6 @@
 // Created by: Vakhtina Elena
 // Created:    2009.02.13
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Collections;
 using Xtensive.Orm.Rse;
 using Xtensive.Orm.Rse.Providers;
diff --git a/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/Connection.cs b/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/Connection.cs
index c05853c94..52aa28299 100644
--- a/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/Connection.cs
+++ b/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/Connection.cs
@@ -4,12 +4,9 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.08.11
 
-using System;
 using System.Data;
 using System.Data.Common;
 using Microsoft.Data.SqlClient;
-using System.Threading;
-using System.Threading.Tasks;
 using SqlServerConnection = Microsoft.Data.SqlClient.SqlConnection;
 
 namespace Xtensive.Sql.Drivers.SqlServer
diff --git a/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/Driver.cs b/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/Driver.cs
index 1f7eaf56d..b61d14217 100644
--- a/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/Driver.cs
+++ b/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/Driver.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.06.23
 
-using System;
-using System.Collections.Generic;
 using Microsoft.Data.SqlClient;
 using Xtensive.Sql.Info;
 
diff --git a/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/DriverFactory.cs b/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/DriverFactory.cs
index 8cf26837c..a13b9ffff 100644
--- a/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/DriverFactory.cs
+++ b/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/DriverFactory.cs
@@ -4,12 +4,8 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.06.23
 
-using System;
-using System.Collections.Generic;
 using System.Data.Common;
 using Microsoft.Data.SqlClient;
-using System.Threading;
-using System.Threading.Tasks;
 using Xtensive.Orm;
 using Xtensive.Sql.Info;
 using Xtensive.SqlServer.Resources;
diff --git a/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/ErrorMessageParser.cs b/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/ErrorMessageParser.cs
index 1e01db1b5..bfcbb43d7 100644
--- a/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/ErrorMessageParser.cs
+++ b/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/ErrorMessageParser.cs
@@ -4,9 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2011.09.28
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Text;
 using System.Text.RegularExpressions;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/InternalHelpers.cs b/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/InternalHelpers.cs
index bc767a3c2..6a72de07d 100644
--- a/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/InternalHelpers.cs
+++ b/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/InternalHelpers.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2020.04.10
 
-using System;
 using Microsoft.Data.SqlClient;
 using System.Data.SqlTypes;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/SqlServerTypeMapper.cs b/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/SqlServerTypeMapper.cs
index 8ba2389ea..42bb6ec5d 100644
--- a/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/SqlServerTypeMapper.cs
+++ b/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/SqlServerTypeMapper.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.06.07
 
-using System;
 using System.Data.Common;
 using Microsoft.Data.SqlClient;
 
diff --git a/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/v09/ColumnResolver.cs b/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/v09/ColumnResolver.cs
index 61f10b951..621534de0 100644
--- a/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/v09/ColumnResolver.cs
+++ b/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/v09/ColumnResolver.cs
@@ -4,9 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2009.08.12
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Sql.Model;
 
 namespace Xtensive.Sql.Drivers.SqlServer.v09
diff --git a/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/v09/Compiler.cs b/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/v09/Compiler.cs
index 7c56b6b41..9325884cd 100644
--- a/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/v09/Compiler.cs
+++ b/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/v09/Compiler.cs
@@ -4,9 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.03.11
 
-using System;
-using System.Linq;
-using System.Collections.Generic;
 using Xtensive.Sql.Compiler;
 using Xtensive.Sql.Info;
 using Xtensive.Sql.Model;
diff --git a/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/v09/Driver.cs b/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/v09/Driver.cs
index 4982557a5..f7f1cedfb 100644
--- a/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/v09/Driver.cs
+++ b/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/v09/Driver.cs
@@ -2,7 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
 using Xtensive.Sql.Compiler;
 using Xtensive.Sql.Info;
 using SqlServerConnection = Microsoft.Data.SqlClient.SqlConnection;
diff --git a/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/v09/Extractor.cs b/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/v09/Extractor.cs
index 23d1c940e..87a5ce20f 100644
--- a/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/v09/Extractor.cs
+++ b/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/v09/Extractor.cs
@@ -4,13 +4,9 @@
 // Created by: Dmitri Maximov
 // Created:    2009.08.11
 
-using System;
-using System.Collections.Generic;
 using System.Data.Common;
 using System.Globalization;
 using System.Text;
-using System.Threading;
-using System.Threading.Tasks;
 using Xtensive.Core;
 using Xtensive.Sql.Info;
 using Xtensive.Sql.Model;
diff --git a/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/v09/ServerInfoProvider.cs b/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/v09/ServerInfoProvider.cs
index f5fe6ad68..805b11790 100644
--- a/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/v09/ServerInfoProvider.cs
+++ b/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/v09/ServerInfoProvider.cs
@@ -2,7 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
 using Xtensive.Sql.Info;
 using SqlServerConnection = Microsoft.Data.SqlClient.SqlConnection;
 
diff --git a/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/v09/Translator.cs b/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/v09/Translator.cs
index 7f07342b1..fda7223f4 100644
--- a/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/v09/Translator.cs
+++ b/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/v09/Translator.cs
@@ -2,10 +2,7 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Collections.Generic;
 using System.Globalization;
-using System.Linq;
 using System.Text;
 using Xtensive.Core;
 using Xtensive.Sql.Compiler;
diff --git a/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/v09/TypeMapper.cs b/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/v09/TypeMapper.cs
index bdc8e83fd..0e4585390 100644
--- a/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/v09/TypeMapper.cs
+++ b/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/v09/TypeMapper.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.07.02
 
-using System;
 using System.Data;
 using System.Data.Common;
 using Microsoft.Data.SqlClient;
diff --git a/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/v10/Compiler.cs b/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/v10/Compiler.cs
index f0ea137ba..efabaf222 100644
--- a/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/v10/Compiler.cs
+++ b/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/v10/Compiler.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.07.07
 
-using System;
 using Xtensive.Sql.Dml;
 
 namespace Xtensive.Sql.Drivers.SqlServer.v10
diff --git a/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/v10/Driver.cs b/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/v10/Driver.cs
index a8bf56e35..04d52a876 100644
--- a/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/v10/Driver.cs
+++ b/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/v10/Driver.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.07.07
 
-using System;
 using Xtensive.Sql.Compiler;
 using Xtensive.Sql.Info;
 
diff --git a/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/v10/ServerInfoProvider.cs b/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/v10/ServerInfoProvider.cs
index c354a8518..a9a97e417 100644
--- a/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/v10/ServerInfoProvider.cs
+++ b/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/v10/ServerInfoProvider.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Kryuchkov
 // Created:    2009.07.07
 
-using System;
 using Xtensive.Sql.Info;
 using SqlServerConnection = Microsoft.Data.SqlClient.SqlConnection;
 
diff --git a/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/v10/Translator.cs b/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/v10/Translator.cs
index 43bd6ee10..63bd9e177 100644
--- a/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/v10/Translator.cs
+++ b/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/v10/Translator.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.07.07
 
-using System;
 using Xtensive.Sql.Compiler;
 using Xtensive.Sql.Dml;
 using Xtensive.Sql.Info;
diff --git a/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/v10/TypeMapper.cs b/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/v10/TypeMapper.cs
index f4424cb1c..76a1064b3 100644
--- a/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/v10/TypeMapper.cs
+++ b/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/v10/TypeMapper.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.07.02
 
-using System;
 using System.Data;
 using System.Data.Common;
 
diff --git a/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/v11/Compiler.cs b/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/v11/Compiler.cs
index b4f91e357..72712bb44 100644
--- a/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/v11/Compiler.cs
+++ b/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/v11/Compiler.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.04.02
 
-using System;
-using System.Collections.Generic;
 using Xtensive.Sql.Compiler;
 using Xtensive.Sql.Dml;
 
diff --git a/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/v11/Extractor.cs b/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/v11/Extractor.cs
index 950ccb9fe..befa524d5 100644
--- a/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/v11/Extractor.cs
+++ b/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/v11/Extractor.cs
@@ -4,11 +4,7 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.04.05
 
-using System;
-using System.Collections.Generic;
 using System.Data.Common;
-using System.Threading;
-using System.Threading.Tasks;
 
 namespace Xtensive.Sql.Drivers.SqlServer.v11
 {
diff --git a/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/v11/Translator.cs b/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/v11/Translator.cs
index f9fddc03c..d87f25e74 100644
--- a/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/v11/Translator.cs
+++ b/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/v11/Translator.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.04.02
 
-using System;
 using System.Text;
 using Xtensive.Sql.Compiler;
 using Xtensive.Sql.Ddl;
diff --git a/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/v13/Driver.cs b/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/v13/Driver.cs
index feb608a1e..3b610805c 100644
--- a/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/v13/Driver.cs
+++ b/Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/v13/Driver.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2018.09.21
 
-using System.Collections.Generic;
 using Xtensive.Sql.Drivers.SqlServer.v10;
 using Xtensive.Sql.Info;
 
diff --git a/Orm/Xtensive.Orm.SqlServer/SqlServer.Resources/Strings.Designer.cs b/Orm/Xtensive.Orm.SqlServer/SqlServer.Resources/Strings.Designer.cs
index 48ff58f17..be0fd4609 100644
--- a/Orm/Xtensive.Orm.SqlServer/SqlServer.Resources/Strings.Designer.cs
+++ b/Orm/Xtensive.Orm.SqlServer/SqlServer.Resources/Strings.Designer.cs
@@ -9,7 +9,6 @@
 //------------------------------------------------------------------------------
 
 namespace Xtensive.SqlServer.Resources {
-    using System;
     
     
     /// <summary>
diff --git a/Orm/Xtensive.Orm.Sqlite/Sql.Drivers.Sqlite/Collations/CurrentCultureCollation.cs b/Orm/Xtensive.Orm.Sqlite/Sql.Drivers.Sqlite/Collations/CurrentCultureCollation.cs
index e6111bf78..6db5e111d 100644
--- a/Orm/Xtensive.Orm.Sqlite/Sql.Drivers.Sqlite/Collations/CurrentCultureCollation.cs
+++ b/Orm/Xtensive.Orm.Sqlite/Sql.Drivers.Sqlite/Collations/CurrentCultureCollation.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.06.05
 
-using System;
 using System.Data.SQLite;
 
 namespace Xtensive.Sql.Drivers.Sqlite.Collations
diff --git a/Orm/Xtensive.Orm.Sqlite/Sql.Drivers.Sqlite/Collations/CurrentCultureIgnoreCaseCollation.cs b/Orm/Xtensive.Orm.Sqlite/Sql.Drivers.Sqlite/Collations/CurrentCultureIgnoreCaseCollation.cs
index ac92bee00..1d5df9d4e 100644
--- a/Orm/Xtensive.Orm.Sqlite/Sql.Drivers.Sqlite/Collations/CurrentCultureIgnoreCaseCollation.cs
+++ b/Orm/Xtensive.Orm.Sqlite/Sql.Drivers.Sqlite/Collations/CurrentCultureIgnoreCaseCollation.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.06.05
 
-using System;
 using System.Data.SQLite;
 
 namespace Xtensive.Sql.Drivers.Sqlite.Collations
diff --git a/Orm/Xtensive.Orm.Sqlite/Sql.Drivers.Sqlite/Collations/InvariantCultureCollation.cs b/Orm/Xtensive.Orm.Sqlite/Sql.Drivers.Sqlite/Collations/InvariantCultureCollation.cs
index 60a70bfb5..9333fa686 100644
--- a/Orm/Xtensive.Orm.Sqlite/Sql.Drivers.Sqlite/Collations/InvariantCultureCollation.cs
+++ b/Orm/Xtensive.Orm.Sqlite/Sql.Drivers.Sqlite/Collations/InvariantCultureCollation.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.06.05
 
-using System;
 using System.Data.SQLite;
 
 namespace Xtensive.Sql.Drivers.Sqlite.Collations
diff --git a/Orm/Xtensive.Orm.Sqlite/Sql.Drivers.Sqlite/Collations/InvariantCultureIgnoreCaseCollation.cs b/Orm/Xtensive.Orm.Sqlite/Sql.Drivers.Sqlite/Collations/InvariantCultureIgnoreCaseCollation.cs
index 9438775c8..f4510b240 100644
--- a/Orm/Xtensive.Orm.Sqlite/Sql.Drivers.Sqlite/Collations/InvariantCultureIgnoreCaseCollation.cs
+++ b/Orm/Xtensive.Orm.Sqlite/Sql.Drivers.Sqlite/Collations/InvariantCultureIgnoreCaseCollation.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.06.05
 
-using System;
 using System.Data.SQLite;
 
 namespace Xtensive.Sql.Drivers.Sqlite.Collations
diff --git a/Orm/Xtensive.Orm.Sqlite/Sql.Drivers.Sqlite/Collations/OrdinalCollation.cs b/Orm/Xtensive.Orm.Sqlite/Sql.Drivers.Sqlite/Collations/OrdinalCollation.cs
index e8debc0e8..62595746f 100644
--- a/Orm/Xtensive.Orm.Sqlite/Sql.Drivers.Sqlite/Collations/OrdinalCollation.cs
+++ b/Orm/Xtensive.Orm.Sqlite/Sql.Drivers.Sqlite/Collations/OrdinalCollation.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.06.05
 
-using System;
 using System.Data.SQLite;
 
 namespace Xtensive.Sql.Drivers.Sqlite.Collations
diff --git a/Orm/Xtensive.Orm.Sqlite/Sql.Drivers.Sqlite/Collations/OrdinalIgnoreCaseCollation.cs b/Orm/Xtensive.Orm.Sqlite/Sql.Drivers.Sqlite/Collations/OrdinalIgnoreCaseCollation.cs
index c4cfb09cc..4144d3d9d 100644
--- a/Orm/Xtensive.Orm.Sqlite/Sql.Drivers.Sqlite/Collations/OrdinalIgnoreCaseCollation.cs
+++ b/Orm/Xtensive.Orm.Sqlite/Sql.Drivers.Sqlite/Collations/OrdinalIgnoreCaseCollation.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.06.05
 
-using System;
 using System.Data.SQLite;
 
 namespace Xtensive.Sql.Drivers.Sqlite.Collations
diff --git a/Orm/Xtensive.Orm.Sqlite/Sql.Drivers.Sqlite/Connection.cs b/Orm/Xtensive.Orm.Sqlite/Sql.Drivers.Sqlite/Connection.cs
index ce9cfb283..69484e7d6 100644
--- a/Orm/Xtensive.Orm.Sqlite/Sql.Drivers.Sqlite/Connection.cs
+++ b/Orm/Xtensive.Orm.Sqlite/Sql.Drivers.Sqlite/Connection.cs
@@ -8,8 +8,6 @@
 using System.Data.Common;
 using System.Data.SQLite;
 using System.Security;
-using System.Threading;
-using System.Threading.Tasks;
 
 namespace Xtensive.Sql.Drivers.Sqlite
 {
diff --git a/Orm/Xtensive.Orm.Sqlite/Sql.Drivers.Sqlite/Driver.cs b/Orm/Xtensive.Orm.Sqlite/Sql.Drivers.Sqlite/Driver.cs
index 32fd6bdea..94d2abac1 100644
--- a/Orm/Xtensive.Orm.Sqlite/Sql.Drivers.Sqlite/Driver.cs
+++ b/Orm/Xtensive.Orm.Sqlite/Sql.Drivers.Sqlite/Driver.cs
@@ -4,7 +4,6 @@
 // Created by: Malisa Ncube
 // Created:    2011.04.29
 
-using System;
 using System.Data.SQLite;
 using System.Security;
 using Xtensive.Sql.Info;
diff --git a/Orm/Xtensive.Orm.Sqlite/Sql.Drivers.Sqlite/DriverFactory.cs b/Orm/Xtensive.Orm.Sqlite/Sql.Drivers.Sqlite/DriverFactory.cs
index 7c152a1df..0f6cd4578 100644
--- a/Orm/Xtensive.Orm.Sqlite/Sql.Drivers.Sqlite/DriverFactory.cs
+++ b/Orm/Xtensive.Orm.Sqlite/Sql.Drivers.Sqlite/DriverFactory.cs
@@ -4,12 +4,9 @@
 // Created by: Malisa Ncube
 // Created:    2011.04.29
 
-using System;
 using System.Data.Common;
 using System.Data.SQLite;
 using System.Text.RegularExpressions;
-using System.Threading;
-using System.Threading.Tasks;
 using Xtensive.Orm;
 using Xtensive.Sql.Drivers.Sqlite.Resources;
 using Xtensive.Sql.Drivers.Sqlite.v3;
diff --git a/Orm/Xtensive.Orm.Sqlite/Sql.Drivers.Sqlite/ProviderInitializer.cs b/Orm/Xtensive.Orm.Sqlite/Sql.Drivers.Sqlite/ProviderInitializer.cs
index 7f528311f..43694debe 100644
--- a/Orm/Xtensive.Orm.Sqlite/Sql.Drivers.Sqlite/ProviderInitializer.cs
+++ b/Orm/Xtensive.Orm.Sqlite/Sql.Drivers.Sqlite/ProviderInitializer.cs
@@ -4,13 +4,10 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.08.21
 
-using System;
 using System.Data.SQLite;
 using System.IO;
-using System.Linq;
 using System.Security.Cryptography;
 using System.Text;
-using System.Threading;
 using Xtensive.Core;
 using Xtensive.Sql.Drivers.Sqlite.Resources;
 
diff --git a/Orm/Xtensive.Orm.Sqlite/Sql.Drivers.Sqlite/Resources/Strings.Designer.cs b/Orm/Xtensive.Orm.Sqlite/Sql.Drivers.Sqlite/Resources/Strings.Designer.cs
index 534561a42..69c620ba0 100644
--- a/Orm/Xtensive.Orm.Sqlite/Sql.Drivers.Sqlite/Resources/Strings.Designer.cs
+++ b/Orm/Xtensive.Orm.Sqlite/Sql.Drivers.Sqlite/Resources/Strings.Designer.cs
@@ -9,7 +9,6 @@
 //------------------------------------------------------------------------------
 
 namespace Xtensive.Sql.Drivers.Sqlite.Resources {
-    using System;
     
     
     /// <summary>
diff --git a/Orm/Xtensive.Orm.Sqlite/Sql.Drivers.Sqlite/v3/Compiler.cs b/Orm/Xtensive.Orm.Sqlite/Sql.Drivers.Sqlite/v3/Compiler.cs
index dc044373f..12d9cee7e 100644
--- a/Orm/Xtensive.Orm.Sqlite/Sql.Drivers.Sqlite/v3/Compiler.cs
+++ b/Orm/Xtensive.Orm.Sqlite/Sql.Drivers.Sqlite/v3/Compiler.cs
@@ -4,9 +4,6 @@
 // Created by: Malisa Ncube
 // Created:    2011.04.29
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Sql.Compiler;
 using Xtensive.Sql.Ddl;
 using Xtensive.Sql.Dml;
diff --git a/Orm/Xtensive.Orm.Sqlite/Sql.Drivers.Sqlite/v3/Driver.cs b/Orm/Xtensive.Orm.Sqlite/Sql.Drivers.Sqlite/v3/Driver.cs
index 1da2c1cd0..5f6b68ba9 100644
--- a/Orm/Xtensive.Orm.Sqlite/Sql.Drivers.Sqlite/v3/Driver.cs
+++ b/Orm/Xtensive.Orm.Sqlite/Sql.Drivers.Sqlite/v3/Driver.cs
@@ -4,7 +4,6 @@
 // Created by: Malisa Ncube
 // Created:    2011.04.29
 
-using System;
 using Xtensive.Sql.Compiler;
 using Xtensive.Sql.Info;
 
diff --git a/Orm/Xtensive.Orm.Sqlite/Sql.Drivers.Sqlite/v3/Extractor.cs b/Orm/Xtensive.Orm.Sqlite/Sql.Drivers.Sqlite/v3/Extractor.cs
index 3d7b0c192..9af649a45 100644
--- a/Orm/Xtensive.Orm.Sqlite/Sql.Drivers.Sqlite/v3/Extractor.cs
+++ b/Orm/Xtensive.Orm.Sqlite/Sql.Drivers.Sqlite/v3/Extractor.cs
@@ -4,14 +4,9 @@
 // Created by: Malisa Ncube
 // Created:    2011.04.29
 
-using System;
-using System.Collections.Generic;
 using System.Data;
 using System.Data.Common;
 using System.Globalization;
-using System.Linq;
-using System.Threading;
-using System.Threading.Tasks;
 using Xtensive.Sql.Model;
 using Index = Xtensive.Sql.Model.Index;
 
diff --git a/Orm/Xtensive.Orm.Sqlite/Sql.Drivers.Sqlite/v3/ServerInfoProvider.cs b/Orm/Xtensive.Orm.Sqlite/Sql.Drivers.Sqlite/v3/ServerInfoProvider.cs
index ffc460b5a..c20633d4e 100644
--- a/Orm/Xtensive.Orm.Sqlite/Sql.Drivers.Sqlite/v3/ServerInfoProvider.cs
+++ b/Orm/Xtensive.Orm.Sqlite/Sql.Drivers.Sqlite/v3/ServerInfoProvider.cs
@@ -4,7 +4,6 @@
 // Created by: Malisa Ncube
 // Created:    2011.04.29
 
-using System;
 using Xtensive.Sql.Info;
 
 namespace Xtensive.Sql.Drivers.Sqlite.v3
diff --git a/Orm/Xtensive.Orm.Sqlite/Sql.Drivers.Sqlite/v3/Translator.cs b/Orm/Xtensive.Orm.Sqlite/Sql.Drivers.Sqlite/v3/Translator.cs
index de11b3502..19b7cd4b6 100644
--- a/Orm/Xtensive.Orm.Sqlite/Sql.Drivers.Sqlite/v3/Translator.cs
+++ b/Orm/Xtensive.Orm.Sqlite/Sql.Drivers.Sqlite/v3/Translator.cs
@@ -4,9 +4,7 @@
 // Created by: Malisa Ncube
 // Created:    2011.04.29
 
-using System;
 using System.Text;
-using System.Linq;
 using Xtensive.Core;
 using Xtensive.Sql.Compiler;
 using Xtensive.Sql.Ddl;
diff --git a/Orm/Xtensive.Orm.Sqlite/Sql.Drivers.Sqlite/v3/TypeMapper.cs b/Orm/Xtensive.Orm.Sqlite/Sql.Drivers.Sqlite/v3/TypeMapper.cs
index eb1ec7f57..6ebd1a134 100644
--- a/Orm/Xtensive.Orm.Sqlite/Sql.Drivers.Sqlite/v3/TypeMapper.cs
+++ b/Orm/Xtensive.Orm.Sqlite/Sql.Drivers.Sqlite/v3/TypeMapper.cs
@@ -4,7 +4,6 @@
 // Created by: Malisa Ncube
 // Created:    2011.04.29
 
-using System;
 using System.Data;
 using System.Data.Common;
 using System.Data.SQLite;
diff --git a/Orm/Xtensive.Orm.Tests.Core/Arithmetics/AritmeticsTest.cs b/Orm/Xtensive.Orm.Tests.Core/Arithmetics/AritmeticsTest.cs
index d0144f08b..f9519f168 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Arithmetics/AritmeticsTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Arithmetics/AritmeticsTest.cs
@@ -4,9 +4,7 @@
 // Created by: Alexey Gamzov
 // Created:    2008.01.22
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
 using NUnit.Framework;
 using Xtensive.Arithmetic;
 using Xtensive.Orm.Tests;
diff --git a/Orm/Xtensive.Orm.Tests.Core/Caching/CachePerformanceTest.cs b/Orm/Xtensive.Orm.Tests.Core/Caching/CachePerformanceTest.cs
index ffba35c3e..e6ae3a7f3 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Caching/CachePerformanceTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Caching/CachePerformanceTest.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.09.27
 
-using System;
-using System.Collections.Generic;
 using System.Diagnostics;
 using NUnit.Framework;
 using Xtensive.Caching;
diff --git a/Orm/Xtensive.Orm.Tests.Core/Caching/FastConcurrentLruCacheTest.cs b/Orm/Xtensive.Orm.Tests.Core/Caching/FastConcurrentLruCacheTest.cs
index 73da0a731..4c5bd7e52 100755
--- a/Orm/Xtensive.Orm.Tests.Core/Caching/FastConcurrentLruCacheTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Caching/FastConcurrentLruCacheTest.cs
@@ -2,9 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Threading;
-using System.Threading.Tasks;
 using NUnit.Framework;
 using Xtensive.Caching;
 using Xtensive.Conversion;
diff --git a/Orm/Xtensive.Orm.Tests.Core/Caching/InfiniteCacheTest.cs b/Orm/Xtensive.Orm.Tests.Core/Caching/InfiniteCacheTest.cs
index 3a364b2aa..b19f13482 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Caching/InfiniteCacheTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Caching/InfiniteCacheTest.cs
@@ -4,9 +4,7 @@
 // Created by: Ivan Galkin
 // Created:    2009.03.11
 
-using System;
 using System.Diagnostics;
-using System.Threading;
 using NUnit.Framework;
 using Xtensive.Caching;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm.Tests.Core/Caching/LruCacheTest.cs b/Orm/Xtensive.Orm.Tests.Core/Caching/LruCacheTest.cs
index f8587b36a..e57fab5af 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Caching/LruCacheTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Caching/LruCacheTest.cs
@@ -2,9 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Threading;
-using System.Threading.Tasks;
 using NUnit.Framework;
 using Xtensive.Caching;
 using Xtensive.Conversion;
diff --git a/Orm/Xtensive.Orm.Tests.Core/Caching/WeakCacheTest.cs b/Orm/Xtensive.Orm.Tests.Core/Caching/WeakCacheTest.cs
index cacb97054..b8eab8249 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Caching/WeakCacheTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Caching/WeakCacheTest.cs
@@ -1,5 +1,3 @@
-using System;
-using System.Threading;
 using NUnit.Framework;
 using Xtensive.Caching;
 using Xtensive.Orm.Tests;
diff --git a/Orm/Xtensive.Orm.Tests.Core/Caching/WeakestCacheTest.cs b/Orm/Xtensive.Orm.Tests.Core/Caching/WeakestCacheTest.cs
index e1f1e3c27..10483c31a 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Caching/WeakestCacheTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Caching/WeakestCacheTest.cs
@@ -4,12 +4,9 @@
 // Created by: Alex Yakunin
 // Created:    2008.09.29
 
-using System;
-using System.Collections.Generic;
 using System.Diagnostics;
 using NUnit.Framework;
 using Xtensive.Caching;
-using System.Linq;
 using Xtensive.Orm.Tests;
 
 namespace Xtensive.Orm.Tests.Core.Caching
diff --git a/Orm/Xtensive.Orm.Tests.Core/Collections/ChainedBufferTest.cs b/Orm/Xtensive.Orm.Tests.Core/Collections/ChainedBufferTest.cs
index 914dd9f98..7d17fdb42 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Collections/ChainedBufferTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Collections/ChainedBufferTest.cs
@@ -4,9 +4,7 @@
 // Created by: Alena Mikshina
 // Created:    2013.08.19
 
-using System.Collections.Generic;
 using System.Diagnostics;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Collections;
 
diff --git a/Orm/Xtensive.Orm.Tests.Core/Collections/CollectionUtilsTest.cs b/Orm/Xtensive.Orm.Tests.Core/Collections/CollectionUtilsTest.cs
index 9171f9639..e36e60074 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Collections/CollectionUtilsTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Collections/CollectionUtilsTest.cs
@@ -4,9 +4,6 @@
 // Created by: Denis Kudelin
 // Created:    2019.03.21
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Text;
 using NUnit.Framework;
 using Xtensive.Collections;
diff --git a/Orm/Xtensive.Orm.Tests.Core/Collections/EnumerableExtensionsTest.cs b/Orm/Xtensive.Orm.Tests.Core/Collections/EnumerableExtensionsTest.cs
index 7b16f3b2e..7e4d04a42 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Collections/EnumerableExtensionsTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Collections/EnumerableExtensionsTest.cs
@@ -4,9 +4,6 @@
 // Created by: Alexander Nikolaev
 // Created:    2009.06.04
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Collections;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm.Tests.Core/Collections/ExtensionCollectionTest.cs b/Orm/Xtensive.Orm.Tests.Core/Collections/ExtensionCollectionTest.cs
index f10d69088..0e2caec6f 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Collections/ExtensionCollectionTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Collections/ExtensionCollectionTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.07.03
 
-using System;
 using NUnit.Framework;
 using Xtensive.Collections;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm.Tests.Core/Collections/FlagCollectionTest.cs b/Orm/Xtensive.Orm.Tests.Core/Collections/FlagCollectionTest.cs
index 312842ed5..10871a6c3 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Collections/FlagCollectionTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Collections/FlagCollectionTest.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Kochetov
 // Created:    2007.10.01
 
-using System;
-using System.Collections.Generic;
 using NUnit.Framework;
 using Xtensive.Collections;
 using Xtensive.Conversion;
diff --git a/Orm/Xtensive.Orm.Tests.Core/Collections/LinkedListTest.cs b/Orm/Xtensive.Orm.Tests.Core/Collections/LinkedListTest.cs
index ef6d57429..e24bee8f9 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Collections/LinkedListTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Collections/LinkedListTest.cs
@@ -4,11 +4,9 @@
 // Created by: Alexis Kochetov
 // Created:    2011.01.17
 
-using System;
 using System.Diagnostics;
 using NUnit.Framework;
 using Xtensive.Collections;
-using System.Linq;
 
 namespace Xtensive.Orm.Tests.Core.Collections
 {
diff --git a/Orm/Xtensive.Orm.Tests.Core/Collections/NativeTypeClassifierTest.cs b/Orm/Xtensive.Orm.Tests.Core/Collections/NativeTypeClassifierTest.cs
index f1bea28ca..e8a6a7979 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Collections/NativeTypeClassifierTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Collections/NativeTypeClassifierTest.cs
@@ -4,14 +4,11 @@
 // Created by: Alex Yakunin
 // Created:    2010.07.02
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
 using System.Diagnostics;
 using NUnit.Framework;
 using Xtensive.Collections;
 using Xtensive.Orm.Tests;
-using System.Linq;
 
 namespace Xtensive.Orm.Tests.Core.Collections
 {
diff --git a/Orm/Xtensive.Orm.Tests.Core/Collections/TopologicalSorterTest.cs b/Orm/Xtensive.Orm.Tests.Core/Collections/TopologicalSorterTest.cs
index 74a37fa23..7ed4ea806 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Collections/TopologicalSorterTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Collections/TopologicalSorterTest.cs
@@ -4,9 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.08.08
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Collections;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm.Tests.Core/Comparison/ComparerProviderTestModel.cs b/Orm/Xtensive.Orm.Tests.Core/Comparison/ComparerProviderTestModel.cs
index f0eb32652..f01967e34 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Comparison/ComparerProviderTestModel.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Comparison/ComparerProviderTestModel.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2007.12.17
 
-using System;
 using Xtensive.Comparison;
 
 namespace Xtensive.Orm.Tests.Core.Comparison
diff --git a/Orm/Xtensive.Orm.Tests.Core/Comparison/ComparerProviderTests.cs b/Orm/Xtensive.Orm.Tests.Core/Comparison/ComparerProviderTests.cs
index ceb9ff259..b4ea66606 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Comparison/ComparerProviderTests.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Comparison/ComparerProviderTests.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2007.12.17
 
-using System;
-using System.Collections.Generic;
 using System.Globalization;
 using System.Reflection;
 using NUnit.Framework;
diff --git a/Orm/Xtensive.Orm.Tests.Core/Comparison/EqualityComparerProviderTests.cs b/Orm/Xtensive.Orm.Tests.Core/Comparison/EqualityComparerProviderTests.cs
index c4c7f8b37..d94b154bf 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Comparison/EqualityComparerProviderTests.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Comparison/EqualityComparerProviderTests.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2007.12.17
 
-using System;
-using System.Collections.Generic;
 using NUnit.Framework;
 using Xtensive.Comparison;
 using Xtensive.Orm.Tests;
diff --git a/Orm/Xtensive.Orm.Tests.Core/Comparison/StringComparisonTest.cs b/Orm/Xtensive.Orm.Tests.Core/Comparison/StringComparisonTest.cs
index caa220f3a..598f338ba 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Comparison/StringComparisonTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Comparison/StringComparisonTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.05.08
 
-using System;
 using System.Globalization;
 using NUnit.Framework;
 
diff --git a/Orm/Xtensive.Orm.Tests.Core/Conversion/ConverterTest.cs b/Orm/Xtensive.Orm.Tests.Core/Conversion/ConverterTest.cs
index 840fb8cf4..9c5ac82bf 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Conversion/ConverterTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Conversion/ConverterTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kochetov
 // Created:    2007.10.03
 
-using System;
 using NUnit.Framework;
 using Xtensive.Collections;
 using Xtensive.Conversion;
diff --git a/Orm/Xtensive.Orm.Tests.Core/Conversion/Internals/BooleanConverterTest.cs b/Orm/Xtensive.Orm.Tests.Core/Conversion/Internals/BooleanConverterTest.cs
index a4627d588..4d1266b69 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Conversion/Internals/BooleanConverterTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Conversion/Internals/BooleanConverterTest.cs
@@ -4,7 +4,6 @@
 // Created by: Roman Churakov
 // Created:    2008.01.25
 
-using System;
 using NUnit.Framework;
 using Xtensive.Conversion;
 using Xtensive.Reflection;
diff --git a/Orm/Xtensive.Orm.Tests.Core/Conversion/Internals/ByteConverterTest.cs b/Orm/Xtensive.Orm.Tests.Core/Conversion/Internals/ByteConverterTest.cs
index 4f0a6b3c9..584ac8946 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Conversion/Internals/ByteConverterTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Conversion/Internals/ByteConverterTest.cs
@@ -4,7 +4,6 @@
 // Created by: Roman Churakov
 // Created:    2008.01.25
 
-using System;
 using NUnit.Framework;
 using Xtensive.Conversion;
 using Xtensive.Reflection;
diff --git a/Orm/Xtensive.Orm.Tests.Core/Conversion/Internals/CharConverterTest.cs b/Orm/Xtensive.Orm.Tests.Core/Conversion/Internals/CharConverterTest.cs
index 8a6467cb1..20128955f 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Conversion/Internals/CharConverterTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Conversion/Internals/CharConverterTest.cs
@@ -4,7 +4,6 @@
 // Created by: Roman Churakov
 // Created:    2008.01.28
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Tests;
 
diff --git a/Orm/Xtensive.Orm.Tests.Core/Conversion/Internals/ConverterTestBase.cs b/Orm/Xtensive.Orm.Tests.Core/Conversion/Internals/ConverterTestBase.cs
index 7db63314a..8e04f8744 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Conversion/Internals/ConverterTestBase.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Conversion/Internals/ConverterTestBase.cs
@@ -5,7 +5,6 @@
 // Created:    2008.01.25
 
 
-using System;
 using NUnit.Framework;
 using Xtensive.Conversion;
 using Xtensive.Reflection;
diff --git a/Orm/Xtensive.Orm.Tests.Core/Conversion/Internals/DateTimeConverterTest.cs b/Orm/Xtensive.Orm.Tests.Core/Conversion/Internals/DateTimeConverterTest.cs
index a39cb6cd9..4a681ba44 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Conversion/Internals/DateTimeConverterTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Conversion/Internals/DateTimeConverterTest.cs
@@ -4,7 +4,6 @@
 // Created by: Roman Churakov
 // Created:    2008.01.25
 
-using System;
 using System.Globalization;
 using NUnit.Framework;
 using Xtensive.Orm.Tests;
diff --git a/Orm/Xtensive.Orm.Tests.Core/Conversion/Internals/DecimalConverterTest.cs b/Orm/Xtensive.Orm.Tests.Core/Conversion/Internals/DecimalConverterTest.cs
index 87cec752b..4cbed058e 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Conversion/Internals/DecimalConverterTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Conversion/Internals/DecimalConverterTest.cs
@@ -4,7 +4,6 @@
 // Created by: Roman Churakov
 // Created:    2008.01.25
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Tests;
 
diff --git a/Orm/Xtensive.Orm.Tests.Core/Conversion/Internals/DoubleConverterTest.cs b/Orm/Xtensive.Orm.Tests.Core/Conversion/Internals/DoubleConverterTest.cs
index f0981b78a..e4ab67719 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Conversion/Internals/DoubleConverterTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Conversion/Internals/DoubleConverterTest.cs
@@ -4,7 +4,6 @@
 // Created by: Roman Churakov
 // Created:    2008.01.25
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Tests;
 
diff --git a/Orm/Xtensive.Orm.Tests.Core/Conversion/Internals/GuidConverterTest.cs b/Orm/Xtensive.Orm.Tests.Core/Conversion/Internals/GuidConverterTest.cs
index fe65a2942..3adb6aff2 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Conversion/Internals/GuidConverterTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Conversion/Internals/GuidConverterTest.cs
@@ -5,7 +5,6 @@
 // Created:    2008.01.25
 
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Tests;
 
diff --git a/Orm/Xtensive.Orm.Tests.Core/Conversion/Internals/Int16ConverterTest.cs b/Orm/Xtensive.Orm.Tests.Core/Conversion/Internals/Int16ConverterTest.cs
index 6638568a7..14989e876 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Conversion/Internals/Int16ConverterTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Conversion/Internals/Int16ConverterTest.cs
@@ -4,7 +4,6 @@
 // Created by: Roman Churakov
 // Created:    2008.01.25
 
-using System;
 using NUnit.Framework;
 using Xtensive.Conversion;
 using Xtensive.Reflection;
diff --git a/Orm/Xtensive.Orm.Tests.Core/Conversion/Internals/Int32ConverterTest.cs b/Orm/Xtensive.Orm.Tests.Core/Conversion/Internals/Int32ConverterTest.cs
index 5ba19cc72..5318de0fa 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Conversion/Internals/Int32ConverterTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Conversion/Internals/Int32ConverterTest.cs
@@ -4,7 +4,6 @@
 // Created by: Roman Churakov
 // Created:    2008.01.25
 
-using System;
 using NUnit.Framework;
 using Xtensive.Conversion;
 using Xtensive.Reflection;
diff --git a/Orm/Xtensive.Orm.Tests.Core/Conversion/Internals/Int64ConverterTest.cs b/Orm/Xtensive.Orm.Tests.Core/Conversion/Internals/Int64ConverterTest.cs
index 94b3672ac..351e07073 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Conversion/Internals/Int64ConverterTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Conversion/Internals/Int64ConverterTest.cs
@@ -4,7 +4,6 @@
 // Created by: Roman Churakov
 // Created:    2008.01.25
 
-using System;
 using NUnit.Framework;
 using Xtensive.Conversion;
 using Xtensive.Reflection;
diff --git a/Orm/Xtensive.Orm.Tests.Core/Conversion/Internals/SByteConverterTest.cs b/Orm/Xtensive.Orm.Tests.Core/Conversion/Internals/SByteConverterTest.cs
index 63f6a048a..5a2165f54 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Conversion/Internals/SByteConverterTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Conversion/Internals/SByteConverterTest.cs
@@ -4,7 +4,6 @@
 // Created by: Roman Churakov
 // Created:    2008.01.25
 
-using System;
 using NUnit.Framework;
 using Xtensive.Conversion;
 using Xtensive.Reflection;
diff --git a/Orm/Xtensive.Orm.Tests.Core/Conversion/Internals/SingleConverterTest.cs b/Orm/Xtensive.Orm.Tests.Core/Conversion/Internals/SingleConverterTest.cs
index 8b2fc6a2a..9b7e976db 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Conversion/Internals/SingleConverterTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Conversion/Internals/SingleConverterTest.cs
@@ -4,7 +4,6 @@
 // Created by: Roman Churakov
 // Created:    2008.01.25
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Tests;
 
diff --git a/Orm/Xtensive.Orm.Tests.Core/Conversion/Internals/StringAdvancedConverter.cs b/Orm/Xtensive.Orm.Tests.Core/Conversion/Internals/StringAdvancedConverter.cs
index 286e41518..fed15d4db 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Conversion/Internals/StringAdvancedConverter.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Conversion/Internals/StringAdvancedConverter.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2008.01.21
 
-using System;
 using Xtensive.Conversion;
 
 namespace Xtensive.Orm.Tests.Core.Conversion
diff --git a/Orm/Xtensive.Orm.Tests.Core/Conversion/Internals/StringConverterTest.cs b/Orm/Xtensive.Orm.Tests.Core/Conversion/Internals/StringConverterTest.cs
index b9403634e..a39c6b5f9 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Conversion/Internals/StringConverterTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Conversion/Internals/StringConverterTest.cs
@@ -4,7 +4,6 @@
 // Created by: Roman Churakov
 // Created:    2008.01.26
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Tests;
 
diff --git a/Orm/Xtensive.Orm.Tests.Core/Conversion/Internals/TestConverterProvider.cs b/Orm/Xtensive.Orm.Tests.Core/Conversion/Internals/TestConverterProvider.cs
index b22328aef..31b908f04 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Conversion/Internals/TestConverterProvider.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Conversion/Internals/TestConverterProvider.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2008.01.21
 
-using System;
 using Xtensive.Conversion;
 
 namespace Xtensive.Orm.Tests.Core.Conversion
diff --git a/Orm/Xtensive.Orm.Tests.Core/Conversion/Internals/TimeSpanConverterTest.cs b/Orm/Xtensive.Orm.Tests.Core/Conversion/Internals/TimeSpanConverterTest.cs
index fa8f8ce84..170706176 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Conversion/Internals/TimeSpanConverterTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Conversion/Internals/TimeSpanConverterTest.cs
@@ -4,7 +4,6 @@
 // Created by: Elena Vakhtina
 // Created:    2008.11.12
 
-using System;
 using System.Globalization;
 using NUnit.Framework;
 using Xtensive.Orm.Tests;
diff --git a/Orm/Xtensive.Orm.Tests.Core/Conversion/Internals/UInt16ConverterTest.cs b/Orm/Xtensive.Orm.Tests.Core/Conversion/Internals/UInt16ConverterTest.cs
index 9a10e2af4..5b93d965c 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Conversion/Internals/UInt16ConverterTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Conversion/Internals/UInt16ConverterTest.cs
@@ -4,7 +4,6 @@
 // Created by: Roman Churakov
 // Created:    2008.01.25
 
-using System;
 using NUnit.Framework;
 using Xtensive.Conversion;
 using Xtensive.Reflection;
diff --git a/Orm/Xtensive.Orm.Tests.Core/Conversion/Internals/UInt32converterTest.cs b/Orm/Xtensive.Orm.Tests.Core/Conversion/Internals/UInt32converterTest.cs
index 7573abf53..d6c4a8cb3 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Conversion/Internals/UInt32converterTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Conversion/Internals/UInt32converterTest.cs
@@ -4,7 +4,6 @@
 // Created by: Roman Churakov
 // Created:    2008.01.25
 
-using System;
 using NUnit.Framework;
 using Xtensive.Conversion;
 using Xtensive.Reflection;
diff --git a/Orm/Xtensive.Orm.Tests.Core/Conversion/Internals/UInt64ConverterTest.cs b/Orm/Xtensive.Orm.Tests.Core/Conversion/Internals/UInt64ConverterTest.cs
index c83e40199..d39a2b98e 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Conversion/Internals/UInt64ConverterTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Conversion/Internals/UInt64ConverterTest.cs
@@ -4,7 +4,6 @@
 // Created by: Roman Churakov
 // Created:    2008.01.25
 
-using System;
 using NUnit.Framework;
 using Xtensive.Conversion;
 using Xtensive.Reflection;
diff --git a/Orm/Xtensive.Orm.Tests.Core/Diagnostics/DebugInfoTest.cs b/Orm/Xtensive.Orm.Tests.Core/Diagnostics/DebugInfoTest.cs
index 6a1ae909e..7570bf21c 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Diagnostics/DebugInfoTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Diagnostics/DebugInfoTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2007.10.03
 
-using System;
 using NUnit.Framework;
 
 namespace Xtensive.Orm.Tests.Core.Diagnostics
diff --git a/Orm/Xtensive.Orm.Tests.Core/Diagnostics/LogMessageTest.cs b/Orm/Xtensive.Orm.Tests.Core/Diagnostics/LogMessageTest.cs
index 9e6520e15..cb64e5e34 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Diagnostics/LogMessageTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Diagnostics/LogMessageTest.cs
@@ -4,7 +4,6 @@
 // Created by: Elena Vakhtina
 // Created:    17.06.2008
 
-using System;
 using System.Globalization;
 using NUnit.Framework;
 
diff --git a/Orm/Xtensive.Orm.Tests.Core/Diagnostics/MeasurementTest.cs b/Orm/Xtensive.Orm.Tests.Core/Diagnostics/MeasurementTest.cs
index 8f426b9a8..3413fbe66 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Diagnostics/MeasurementTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Diagnostics/MeasurementTest.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2007.10.03
 
-using System;
-using System.Threading;
 using NUnit.Framework;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm.Tests.Core/Diagnostics/RuntimeInfoTest.cs b/Orm/Xtensive.Orm.Tests.Core/Diagnostics/RuntimeInfoTest.cs
index e825babfc..d2f09ae6f 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Diagnostics/RuntimeInfoTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Diagnostics/RuntimeInfoTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2007.10.03
 
-using System;
 using NUnit.Framework;
 
 namespace Xtensive.Orm.Tests.Core.Diagnostics
diff --git a/Orm/Xtensive.Orm.Tests.Core/DotNetFramework/AllocationTest.cs b/Orm/Xtensive.Orm.Tests.Core/DotNetFramework/AllocationTest.cs
index 3a4dacdac..f921bc7a7 100644
--- a/Orm/Xtensive.Orm.Tests.Core/DotNetFramework/AllocationTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/DotNetFramework/AllocationTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.04.17
 
-using System;
 using System.Runtime.Serialization;
 using NUnit.Framework;
 using Xtensive.Reflection;
diff --git a/Orm/Xtensive.Orm.Tests.Core/DotNetFramework/CallTest.cs b/Orm/Xtensive.Orm.Tests.Core/DotNetFramework/CallTest.cs
index 5526bff77..325c1736e 100644
--- a/Orm/Xtensive.Orm.Tests.Core/DotNetFramework/CallTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/DotNetFramework/CallTest.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.01.29
 
-using System;
-using System.Threading;
 using NUnit.Framework;
 using Xtensive.Collections;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm.Tests.Core/DotNetFramework/CastTest.cs b/Orm/Xtensive.Orm.Tests.Core/DotNetFramework/CastTest.cs
index 37bef44b0..8ec23a754 100644
--- a/Orm/Xtensive.Orm.Tests.Core/DotNetFramework/CastTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/DotNetFramework/CastTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kochetov
 // Created:    2008.11.21
 
-using System;
 using NUnit.Framework;
 
 namespace Xtensive.Orm.Tests.Core.DotNetFramework
diff --git a/Orm/Xtensive.Orm.Tests.Core/DotNetFramework/CloningTest.cs b/Orm/Xtensive.Orm.Tests.Core/DotNetFramework/CloningTest.cs
index 0db3920df..efd1985b7 100644
--- a/Orm/Xtensive.Orm.Tests.Core/DotNetFramework/CloningTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/DotNetFramework/CloningTest.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.01.24
 
-using System;
-using System.Threading;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Orm.Logging;
diff --git a/Orm/Xtensive.Orm.Tests.Core/DotNetFramework/CoreFeaturesTest.cs b/Orm/Xtensive.Orm.Tests.Core/DotNetFramework/CoreFeaturesTest.cs
index 9a9239f74..36c26854b 100644
--- a/Orm/Xtensive.Orm.Tests.Core/DotNetFramework/CoreFeaturesTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/DotNetFramework/CoreFeaturesTest.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.04.17
 
-using System;
-using System.Collections.Generic;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Orm.Tests;
diff --git a/Orm/Xtensive.Orm.Tests.Core/DotNetFramework/FieldTypeTest.cs b/Orm/Xtensive.Orm.Tests.Core/DotNetFramework/FieldTypeTest.cs
index 98676216f..d9dea9315 100644
--- a/Orm/Xtensive.Orm.Tests.Core/DotNetFramework/FieldTypeTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/DotNetFramework/FieldTypeTest.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.09.01
 
-using System;
-using System.Threading;
 using NUnit.Framework;
 
 namespace Xtensive.Orm.Tests.Core.DotNetFramework
diff --git a/Orm/Xtensive.Orm.Tests.Core/DotNetFramework/GenericFeaturesTest.cs b/Orm/Xtensive.Orm.Tests.Core/DotNetFramework/GenericFeaturesTest.cs
index 2c00a6682..6f92844e7 100644
--- a/Orm/Xtensive.Orm.Tests.Core/DotNetFramework/GenericFeaturesTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/DotNetFramework/GenericFeaturesTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.01.24
 
-using System;
 using NUnit.Framework;
 using Xtensive.Reflection;
 
diff --git a/Orm/Xtensive.Orm.Tests.Core/DotNetFramework/InterfaceTest.cs b/Orm/Xtensive.Orm.Tests.Core/DotNetFramework/InterfaceTest.cs
index cb3ae6ab5..f82fd63f0 100644
--- a/Orm/Xtensive.Orm.Tests.Core/DotNetFramework/InterfaceTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/DotNetFramework/InterfaceTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.10.01
 
-using System;
 using System.Diagnostics;
 using NUnit.Framework;
 
diff --git a/Orm/Xtensive.Orm.Tests.Core/DotNetFramework/MemoryAccessTypeTest.cs b/Orm/Xtensive.Orm.Tests.Core/DotNetFramework/MemoryAccessTypeTest.cs
index 4e7727b64..e7af7cb1f 100644
--- a/Orm/Xtensive.Orm.Tests.Core/DotNetFramework/MemoryAccessTypeTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/DotNetFramework/MemoryAccessTypeTest.cs
@@ -4,10 +4,7 @@
 // Created by: Alex Yakunin
 // Created:    2008.04.17
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Reflection;
diff --git a/Orm/Xtensive.Orm.Tests.Core/DotNetFramework/NewTupleLogicTest.cs b/Orm/Xtensive.Orm.Tests.Core/DotNetFramework/NewTupleLogicTest.cs
index 74db2645c..1a705991e 100644
--- a/Orm/Xtensive.Orm.Tests.Core/DotNetFramework/NewTupleLogicTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/DotNetFramework/NewTupleLogicTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2009.09.02
 
-using System;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Orm.Tests;
diff --git a/Orm/Xtensive.Orm.Tests.Core/DotNetFramework/PointersTest.cs b/Orm/Xtensive.Orm.Tests.Core/DotNetFramework/PointersTest.cs
index 073ba0b42..fe334849f 100644
--- a/Orm/Xtensive.Orm.Tests.Core/DotNetFramework/PointersTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/DotNetFramework/PointersTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.05.27
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Logging;
 using Xtensive.Reflection;
diff --git a/Orm/Xtensive.Orm.Tests.Core/DotNetFramework/StaticMethodTest.cs b/Orm/Xtensive.Orm.Tests.Core/DotNetFramework/StaticMethodTest.cs
index 817928f47..72502d2d9 100644
--- a/Orm/Xtensive.Orm.Tests.Core/DotNetFramework/StaticMethodTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/DotNetFramework/StaticMethodTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.09.16
 
-using System;
 using System.Diagnostics;
 using System.Reflection;
 using NUnit.Framework;
diff --git a/Orm/Xtensive.Orm.Tests.Core/DotNetFramework/SwitchVsArrayTest.cs b/Orm/Xtensive.Orm.Tests.Core/DotNetFramework/SwitchVsArrayTest.cs
index a4447c63e..68248e4aa 100644
--- a/Orm/Xtensive.Orm.Tests.Core/DotNetFramework/SwitchVsArrayTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/DotNetFramework/SwitchVsArrayTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.09.15
 
-using System;
 using System.Diagnostics;
 using NUnit.Framework;
 
diff --git a/Orm/Xtensive.Orm.Tests.Core/DotNetFramework/ThreadingTest.cs b/Orm/Xtensive.Orm.Tests.Core/DotNetFramework/ThreadingTest.cs
index 18f04de9a..a5c847371 100644
--- a/Orm/Xtensive.Orm.Tests.Core/DotNetFramework/ThreadingTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/DotNetFramework/ThreadingTest.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.05.27
 
-using System;
-using System.Threading;
 using NUnit.Framework;
 using Xtensive.Orm.Logging;
 using Xtensive.Reflection;
diff --git a/Orm/Xtensive.Orm.Tests.Core/DotNetFramework/ValidationTest.cs b/Orm/Xtensive.Orm.Tests.Core/DotNetFramework/ValidationTest.cs
index fc00d2211..ba826587d 100644
--- a/Orm/Xtensive.Orm.Tests.Core/DotNetFramework/ValidationTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/DotNetFramework/ValidationTest.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.01.24
 
-using System;
-using System.Threading;
 using NUnit.Framework;
 using Xtensive.Orm.Logging;
 using Xtensive.Reflection;
diff --git a/Orm/Xtensive.Orm.Tests.Core/GlobalTestSetup.cs b/Orm/Xtensive.Orm.Tests.Core/GlobalTestSetup.cs
index 2237b4952..caa5dd052 100644
--- a/Orm/Xtensive.Orm.Tests.Core/GlobalTestSetup.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/GlobalTestSetup.cs
@@ -2,7 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Logging;
 
diff --git a/Orm/Xtensive.Orm.Tests.Core/Helpers/StringExtensionsTest.cs b/Orm/Xtensive.Orm.Tests.Core/Helpers/StringExtensionsTest.cs
index 20216335a..d944ca560 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Helpers/StringExtensionsTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Helpers/StringExtensionsTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2009.03.17
 
-using System;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Orm.Tests;
diff --git a/Orm/Xtensive.Orm.Tests.Core/Helpers/TopologicalSorterTest.cs b/Orm/Xtensive.Orm.Tests.Core/Helpers/TopologicalSorterTest.cs
index 379c65a31..a81b7ad13 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Helpers/TopologicalSorterTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Helpers/TopologicalSorterTest.cs
@@ -4,9 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.08.08
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Text;
 using NUnit.Framework;
 using Xtensive.Collections;
diff --git a/Orm/Xtensive.Orm.Tests.Core/IoC/MainTest.cs b/Orm/Xtensive.Orm.Tests.Core/IoC/MainTest.cs
index ce85544c2..75b9e1764 100644
--- a/Orm/Xtensive.Orm.Tests.Core/IoC/MainTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/IoC/MainTest.cs
@@ -4,11 +4,8 @@
 // Created by: Dmitri Maximov
 // Created:    2009.12.15
 
-using System;
-using System.Collections.Generic;
 using System.Configuration;
 using System.Diagnostics;
-using System.Threading;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.IoC;
diff --git a/Orm/Xtensive.Orm.Tests.Core/Linq/CachingExpressionCompilerTest.cs b/Orm/Xtensive.Orm.Tests.Core/Linq/CachingExpressionCompilerTest.cs
index f2cb9a7f4..2349654de 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Linq/CachingExpressionCompilerTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Linq/CachingExpressionCompilerTest.cs
@@ -4,9 +4,7 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.05.07
 
-using System;
 using System.Collections;
-using System.Linq;
 using System.Linq.Expressions;
 using System.Reflection;
 using NUnit.Framework;
diff --git a/Orm/Xtensive.Orm.Tests.Core/Linq/ConstantExtractorTest.cs b/Orm/Xtensive.Orm.Tests.Core/Linq/ConstantExtractorTest.cs
index 660557bc7..7744d78f1 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Linq/ConstantExtractorTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Linq/ConstantExtractorTest.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.05.07
 
-using System;
 using System.Linq.Expressions;
 using NUnit.Framework;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm.Tests.Core/Linq/ExpressionTestBase.cs b/Orm/Xtensive.Orm.Tests.Core/Linq/ExpressionTestBase.cs
index f22b642f2..d60f48c07 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Linq/ExpressionTestBase.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Linq/ExpressionTestBase.cs
@@ -4,9 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.05.13
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Linq.Expressions;
 using NUnit.Framework;
 using Xtensive.Collections;
diff --git a/Orm/Xtensive.Orm.Tests.Core/Linq/ExpressionTreeTest.cs b/Orm/Xtensive.Orm.Tests.Core/Linq/ExpressionTreeTest.cs
index 109f0bd36..4485df6cc 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Linq/ExpressionTreeTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Linq/ExpressionTreeTest.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.05.07
 
-using System;
 using System.Linq.Expressions;
 using NUnit.Framework;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm.Tests.Core/Linq/ExpressionWriterTest.cs b/Orm/Xtensive.Orm.Tests.Core/Linq/ExpressionWriterTest.cs
index 677e34d63..5beb3b431 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Linq/ExpressionWriterTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Linq/ExpressionWriterTest.cs
@@ -4,9 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2009.02.09
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm.Tests.Core/Linq/LambdaExpressionFactoryTests.cs b/Orm/Xtensive.Orm.Tests.Core/Linq/LambdaExpressionFactoryTests.cs
index 540483038..a0ae8221c 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Linq/LambdaExpressionFactoryTests.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Linq/LambdaExpressionFactoryTests.cs
@@ -2,7 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
 using System.Linq.Expressions;
 using NUnit.Framework;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm.Tests.Core/Linq/SerializableExpressionsTest.cs b/Orm/Xtensive.Orm.Tests.Core/Linq/SerializableExpressionsTest.cs
index 3be10691f..e7deaf406 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Linq/SerializableExpressionsTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Linq/SerializableExpressionsTest.cs
@@ -4,9 +4,7 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.05.13
 
-using System;
 using System.IO;
-using System.Linq;
 using System.Runtime.Serialization;
 using System.Runtime.Serialization.Formatters.Binary;
 using System.Runtime.Serialization.Formatters;
@@ -14,7 +12,6 @@
 using Xtensive.Core;
 using Xtensive.Linq;
 using Xtensive.Linq.SerializableExpressions;
-using System.Collections.Generic;
 
 namespace Xtensive.Orm.Tests.Core.Linq
 {
diff --git a/Orm/Xtensive.Orm.Tests.Core/Logging/LogManagerTests.cs b/Orm/Xtensive.Orm.Tests.Core/Logging/LogManagerTests.cs
index 0b1b85b3e..e5ef2e9f2 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Logging/LogManagerTests.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Logging/LogManagerTests.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2013.10.14
 
-using System;
-using System.Collections.Generic;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Logging;
diff --git a/Orm/Xtensive.Orm.Tests.Core/Logging/WriteToLogInstanceTests.cs b/Orm/Xtensive.Orm.Tests.Core/Logging/WriteToLogInstanceTests.cs
index 2583e31a9..f9446ca7b 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Logging/WriteToLogInstanceTests.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Logging/WriteToLogInstanceTests.cs
@@ -4,10 +4,8 @@
 // Created by: Alexey Kulakov
 // Created:    2013.10.14
 
-using System;
 using System.Diagnostics;
 using System.IO;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Logging;
diff --git a/Orm/Xtensive.Orm.Tests.Core/Logging/WriteToLogTests.cs b/Orm/Xtensive.Orm.Tests.Core/Logging/WriteToLogTests.cs
index 171623b62..04003b0e8 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Logging/WriteToLogTests.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Logging/WriteToLogTests.cs
@@ -4,9 +4,7 @@
 // Created by: Alexey Kulakov
 // Created:    2013.10.14
 
-using System;
 using System.IO;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Logging;
diff --git a/Orm/Xtensive.Orm.Tests.Core/Modelling/DataUpgradeTest.cs b/Orm/Xtensive.Orm.Tests.Core/Modelling/DataUpgradeTest.cs
index 6ff682ae6..6b98e4de6 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Modelling/DataUpgradeTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Modelling/DataUpgradeTest.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2009.04.17
 
-using System;
-using System.Collections.Generic;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Modelling.Actions;
diff --git a/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/Database.cs b/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/Database.cs
index 435b0edc1..382e521fc 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/Database.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/Database.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2009.03.18
 
-using System;
 using Xtensive.Modelling;
 using Xtensive.Modelling.Attributes;
 
diff --git a/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/DatabaseCollection.cs b/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/DatabaseCollection.cs
index 1d5d328e7..f06ec8741 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/DatabaseCollection.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/DatabaseCollection.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2009.03.18
 
-using System;
 using System.Diagnostics;
 using Xtensive.Modelling;
 
diff --git a/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/Index.cs b/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/Index.cs
index 84452cc47..8e36846dc 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/Index.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/Index.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2009.03.18
 
-using System;
 using Xtensive.Core;
 using Xtensive.Modelling.Attributes;
 
diff --git a/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/IndexCollection.cs b/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/IndexCollection.cs
index a2052e80d..becc7cefc 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/IndexCollection.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/IndexCollection.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2009.03.18
 
-using System;
 using System.Diagnostics;
 using Xtensive.Modelling;
 
diff --git a/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/NodeBase.cs b/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/NodeBase.cs
index 29afd7989..3fa1ad604 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/NodeBase.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/NodeBase.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2009.03.20
 
-using System;
 using System.Diagnostics;
 using Xtensive.Modelling;
 using Xtensive.Reflection;
diff --git a/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/NodeCollectionBase.cs b/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/NodeCollectionBase.cs
index 3d8839313..2712965d5 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/NodeCollectionBase.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/NodeCollectionBase.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2009.03.20
 
-using System;
 using Xtensive.Modelling;
 
 namespace Xtensive.Orm.Tests.Core.Modelling.DatabaseModel
diff --git a/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/PrimaryIndex.cs b/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/PrimaryIndex.cs
index 75c205e02..8ddf4b792 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/PrimaryIndex.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/PrimaryIndex.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2009.03.18
 
-using System;
 using System.Diagnostics;
 using Xtensive.Modelling;
 
diff --git a/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/Ref.cs b/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/Ref.cs
index 1eee59cc9..c244f3a7e 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/Ref.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/Ref.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2009.03.20
 
-using System;
 using System.Diagnostics;
 using Xtensive.Core;
 using Xtensive.Modelling;
diff --git a/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/Role.cs b/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/Role.cs
index f004264e1..702ab08c8 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/Role.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/Role.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2009.03.18
 
-using System;
 using Xtensive.Modelling;
 
 namespace Xtensive.Orm.Tests.Core.Modelling.DatabaseModel
diff --git a/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/RoleCollection.cs b/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/RoleCollection.cs
index 0eecf9fa9..c593f354b 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/RoleCollection.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/RoleCollection.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2009.03.18
 
-using System;
 using System.Diagnostics;
 using Xtensive.Modelling;
 
diff --git a/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/RoleRef.cs b/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/RoleRef.cs
index 427f86f72..1a1e32c63 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/RoleRef.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/RoleRef.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2009.03.20
 
-using System;
 using System.Diagnostics;
 using Xtensive.Modelling;
 
diff --git a/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/RoleRefCollection.cs b/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/RoleRefCollection.cs
index adda544c0..2c54c1909 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/RoleRefCollection.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/RoleRefCollection.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2009.03.20
 
-using System;
 using System.Diagnostics;
 using Xtensive.Modelling;
 
diff --git a/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/Schema.cs b/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/Schema.cs
index 5a8dd1c82..d5c93e98a 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/Schema.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/Schema.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2009.03.18
 
-using System;
 using System.Diagnostics;
 using Xtensive.Modelling;
 using Xtensive.Modelling.Attributes;
diff --git a/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/SchemaCollection.cs b/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/SchemaCollection.cs
index 651a456b2..ac9365525 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/SchemaCollection.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/SchemaCollection.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2009.03.18
 
-using System;
 using System.Diagnostics;
 using Xtensive.Modelling;
 
diff --git a/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/SecondaryIndex.cs b/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/SecondaryIndex.cs
index 51439de0c..8f9de43e6 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/SecondaryIndex.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/SecondaryIndex.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2009.03.18
 
-using System;
 using System.Diagnostics;
 using Xtensive.Modelling;
 
diff --git a/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/Security.cs b/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/Security.cs
index 77199376c..12c7d8006 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/Security.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/Security.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2009.03.20
 
-using System;
 using System.Diagnostics;
 using Xtensive.Modelling;
 using Xtensive.Modelling.Attributes;
diff --git a/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/Server.cs b/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/Server.cs
index 0bafffe51..8c00ddf1f 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/Server.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/Server.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2009.03.18
 
-using System;
 using Xtensive.Modelling;
 using Xtensive.Modelling.Actions;
 using Xtensive.Modelling.Attributes;
diff --git a/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/Table.cs b/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/Table.cs
index 8e7b59e6e..0a9fb75f2 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/Table.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/Table.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2009.03.18
 
-using System;
 using Xtensive.Modelling;
 using Xtensive.Modelling.Attributes;
 
diff --git a/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/TableCollection.cs b/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/TableCollection.cs
index 7c5b0182b..c48c0d6d5 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/TableCollection.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/TableCollection.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2009.03.18
 
-using System;
 using System.Diagnostics;
 using Xtensive.Modelling;
 
diff --git a/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/User.cs b/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/User.cs
index 53f13312c..c636052ea 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/User.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/User.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2009.03.18
 
-using System;
 using System.Diagnostics;
 using Xtensive.Modelling;
 using Xtensive.Modelling.Attributes;
diff --git a/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/UserCollection.cs b/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/UserCollection.cs
index 2683106ac..3d2e3f663 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/UserCollection.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModel/UserCollection.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2009.03.18
 
-using System;
 using System.Diagnostics;
 
 namespace Xtensive.Orm.Tests.Core.Modelling.DatabaseModel
diff --git a/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModelTest.cs b/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModelTest.cs
index a41d8497a..6dbc2a510 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModelTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Modelling/DatabaseModelTest.cs
@@ -4,9 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2009.03.18
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Modelling;
diff --git a/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/ColumnInfo.cs b/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/ColumnInfo.cs
index d47c3b9da..f02b95616 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/ColumnInfo.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/ColumnInfo.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.03.20
 
-using System;
 using Xtensive.Core;
 using Xtensive.Modelling;
 using Xtensive.Modelling.Attributes;
diff --git a/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/ColumnInfoCollection.cs b/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/ColumnInfoCollection.cs
index 7011fd26a..bdaae5ceb 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/ColumnInfoCollection.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/ColumnInfoCollection.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.03.20
 
-using System;
 using Xtensive.Modelling;
 
 namespace Xtensive.Orm.Tests.Core.Modelling.IndexingModel
diff --git a/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/ColumnInfoRef.cs b/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/ColumnInfoRef.cs
index 7fe17fe2d..c061cb3ee 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/ColumnInfoRef.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/ColumnInfoRef.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.03.20
 
-using System;
 using Xtensive.Modelling;
 
 namespace Xtensive.Orm.Tests.Core.Modelling.IndexingModel
diff --git a/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/Exceptions/ValidationException.cs b/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/Exceptions/ValidationException.cs
index a6647d965..b09ba07df 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/Exceptions/ValidationException.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/Exceptions/ValidationException.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.03.23
 
-using System;
 using System.Runtime.Serialization;
 using System.Security;
 using System.Security.Permissions;
diff --git a/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/ForeignKeyCollection.cs b/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/ForeignKeyCollection.cs
index 9c02cab01..b3af6366f 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/ForeignKeyCollection.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/ForeignKeyCollection.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.03.23
 
-using System;
 using Xtensive.Modelling;
 
 namespace Xtensive.Orm.Tests.Core.Modelling.IndexingModel
diff --git a/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/ForeignKeyColumnCollection.cs b/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/ForeignKeyColumnCollection.cs
index 6b9193660..a2fc1149e 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/ForeignKeyColumnCollection.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/ForeignKeyColumnCollection.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.04.20
 
-using System;
 using System.Diagnostics;
 using Xtensive.Modelling;
 
diff --git a/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/ForeignKeyColumnRef.cs b/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/ForeignKeyColumnRef.cs
index 7f469190d..ff1a454cf 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/ForeignKeyColumnRef.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/ForeignKeyColumnRef.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.04.20
 
-using System;
 using Xtensive.Modelling;
 
 namespace Xtensive.Orm.Tests.Core.Modelling.IndexingModel
diff --git a/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/ForeignKeyInfo.cs b/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/ForeignKeyInfo.cs
index c34be4bd4..7880bbc06 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/ForeignKeyInfo.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/ForeignKeyInfo.cs
@@ -4,8 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.03.23
 
-using System;
-using System.Linq;
 using Xtensive.Core;
 using Xtensive.Modelling;
 using Xtensive.Modelling.Attributes;
diff --git a/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/FullTextColumnRef.cs b/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/FullTextColumnRef.cs
index c30dca295..2599b60bf 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/FullTextColumnRef.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/FullTextColumnRef.cs
@@ -5,7 +5,6 @@
 // Created:    2010.01.14
 
 
-using System;
 using Xtensive.Modelling;
 using Xtensive.Modelling.Attributes;
 
diff --git a/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/FullTextColumnRefCollection.cs b/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/FullTextColumnRefCollection.cs
index bec3e5c11..b2411baba 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/FullTextColumnRefCollection.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/FullTextColumnRefCollection.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2010.01.14
 
-using System;
 
 namespace Xtensive.Orm.Tests.Core.Modelling.IndexingModel
 {
diff --git a/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/FullTextIndexInfo.cs b/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/FullTextIndexInfo.cs
index 2409eea7c..ddd60963e 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/FullTextIndexInfo.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/FullTextIndexInfo.cs
@@ -4,8 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2010.01.14
 
-using System;
-using System.Linq;
 using Xtensive.Core;
 using Xtensive.Modelling;
 using Xtensive.Modelling.Attributes;
diff --git a/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/IncludedColumnRef.cs b/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/IncludedColumnRef.cs
index 75fbaffe6..94e67e7cb 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/IncludedColumnRef.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/IncludedColumnRef.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.03.24
 
-using System;
 using Xtensive.Modelling;
 
 namespace Xtensive.Orm.Tests.Core.Modelling.IndexingModel
diff --git a/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/IncludedColumnRefCollection.cs b/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/IncludedColumnRefCollection.cs
index 3f4e5288c..803858f30 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/IncludedColumnRefCollection.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/IncludedColumnRefCollection.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.03.24
 
-using System;
 
 namespace Xtensive.Orm.Tests.Core.Modelling.IndexingModel
 {
diff --git a/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/IndexInfo.cs b/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/IndexInfo.cs
index 6224231d9..f535b6337 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/IndexInfo.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/IndexInfo.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.03.24
 
-using System;
 using Xtensive.Core;
 using Xtensive.Modelling.Attributes;
 
diff --git a/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/KeyColumnRef.cs b/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/KeyColumnRef.cs
index 8d1bb3b13..0bbf5c8aa 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/KeyColumnRef.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/KeyColumnRef.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.03.20
 
-using System;
 using Xtensive.Core;
 using Xtensive.Modelling;
 
diff --git a/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/KeyColumnRefCollection.cs b/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/KeyColumnRefCollection.cs
index 504a90d3d..dbd7aa71e 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/KeyColumnRefCollection.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/KeyColumnRefCollection.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.03.20
 
-using System;
 
 namespace Xtensive.Orm.Tests.Core.Modelling.IndexingModel
 {
diff --git a/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/KeyColumnRef{TParent}.cs b/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/KeyColumnRef{TParent}.cs
index deb028256..28dd12279 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/KeyColumnRef{TParent}.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/KeyColumnRef{TParent}.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.03.20
 
-using System;
 using Xtensive.Core;
 using Xtensive.Modelling.Attributes;
 
diff --git a/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/NodeBase.cs b/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/NodeBase.cs
index c47f869a4..d648cb4f6 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/NodeBase.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/NodeBase.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.03.20
 
-using System;
 using Xtensive.Modelling;
 
 namespace Xtensive.Orm.Tests.Core.Modelling.IndexingModel
diff --git a/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/NodeCollectionBase.cs b/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/NodeCollectionBase.cs
index bbb648a25..12153c3db 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/NodeCollectionBase.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/NodeCollectionBase.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.03.20
 
-using System;
 using Xtensive.Modelling;
 
 namespace Xtensive.Orm.Tests.Core.Modelling.IndexingModel
diff --git a/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/PrimaryIndexInfo.cs b/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/PrimaryIndexInfo.cs
index 4c0811efa..5c7a650ce 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/PrimaryIndexInfo.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/PrimaryIndexInfo.cs
@@ -4,8 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.03.20
 
-using System;
-using System.Linq;
 using Xtensive.Core;
 using Xtensive.Modelling;
 using Xtensive.Modelling.Attributes;
diff --git a/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/PrimaryKeyColumnRef.cs b/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/PrimaryKeyColumnRef.cs
index 191a50fbe..002d619c1 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/PrimaryKeyColumnRef.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/PrimaryKeyColumnRef.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.03.20
 
-using System;
 using Xtensive.Core;
 using Xtensive.Modelling;
 
diff --git a/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/PrimaryKeyColumnRefCollection.cs b/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/PrimaryKeyColumnRefCollection.cs
index 844273704..8227543a6 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/PrimaryKeyColumnRefCollection.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/PrimaryKeyColumnRefCollection.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.03.20
 
-using System;
 
 namespace Xtensive.Orm.Tests.Core.Modelling.IndexingModel
 {
diff --git a/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/Ref.cs b/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/Ref.cs
index cd8e86d98..ae595bbcc 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/Ref.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/Ref.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.03.20
 
-using System;
 using Xtensive.Core;
 using Xtensive.Modelling;
 using Xtensive.Modelling.Attributes;
diff --git a/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/ReferentialAction.cs b/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/ReferentialAction.cs
index 36a034236..5555ceac7 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/ReferentialAction.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/ReferentialAction.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.03.17
 
-using System;
 
 namespace Xtensive.Orm.Tests.Core.Modelling.IndexingModel
 {
diff --git a/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/Resources/Strings.Designer.cs b/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/Resources/Strings.Designer.cs
index a3a100a1c..431d80644 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/Resources/Strings.Designer.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/Resources/Strings.Designer.cs
@@ -9,7 +9,6 @@
 //------------------------------------------------------------------------------
 
 namespace Xtensive.Modelling.IndexingModel.Resources {
-    using System;
     
     
     /// <summary>
diff --git a/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/SecondaryIndexInfo.cs b/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/SecondaryIndexInfo.cs
index 41cf92906..1017a12f5 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/SecondaryIndexInfo.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/SecondaryIndexInfo.cs
@@ -4,8 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.03.20
 
-using System;
-using System.Linq;
 using Xtensive.Core;
 using Xtensive.Modelling;
 using Xtensive.Modelling.Attributes;
diff --git a/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/SecondaryIndexInfoCollection.cs b/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/SecondaryIndexInfoCollection.cs
index 1975d2e95..dd5f51699 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/SecondaryIndexInfoCollection.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/SecondaryIndexInfoCollection.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.03.20
 
-using System;
 using Xtensive.Modelling;
 
 namespace Xtensive.Orm.Tests.Core.Modelling.IndexingModel
diff --git a/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/StorageInfo.cs b/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/StorageInfo.cs
index 8f59c2558..5113d4b02 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/StorageInfo.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/StorageInfo.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.03.20
 
-using System;
 using Xtensive.Modelling;
 using Xtensive.Modelling.Actions;
 using Xtensive.Modelling.Attributes;
diff --git a/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/TableInfo.cs b/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/TableInfo.cs
index 296d2a817..4197ed5fa 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/TableInfo.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/TableInfo.cs
@@ -4,10 +4,8 @@
 // Created by: Ivan Galkin
 // Created:    2009.03.24
 
-using System;
 using Xtensive.Modelling;
 using Xtensive.Modelling.Attributes;
-using System.Collections.Generic;
 
 namespace Xtensive.Orm.Tests.Core.Modelling.IndexingModel
 {
diff --git a/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/TableInfoCollection.cs b/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/TableInfoCollection.cs
index a0a66c6bd..278193700 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/TableInfoCollection.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/TableInfoCollection.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.03.24
 
-using System;
 using Xtensive.Modelling;
 
 namespace Xtensive.Orm.Tests.Core.Modelling.IndexingModel
diff --git a/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/TypeInfo.cs b/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/TypeInfo.cs
index 435407435..659430951 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/TypeInfo.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/TypeInfo.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.03.24
 
-using System;
 using System.Globalization;
 using Xtensive.Core;
 using System.Text;
diff --git a/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/ValueColumnRef.cs b/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/ValueColumnRef.cs
index 68b09354e..2457eff5b 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/ValueColumnRef.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/ValueColumnRef.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.03.24
 
-using System;
 using Xtensive.Modelling;
 
 namespace Xtensive.Orm.Tests.Core.Modelling.IndexingModel
diff --git a/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/ValueColumnRefCollection.cs b/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/ValueColumnRefCollection.cs
index 59036d095..cd11926ab 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/ValueColumnRefCollection.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/ValueColumnRefCollection.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.03.24
 
-using System;
 
 namespace Xtensive.Orm.Tests.Core.Modelling.IndexingModel
 {
diff --git a/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModelTest.cs b/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModelTest.cs
index c17e16a1f..79e5b6d3e 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModelTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModelTest.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2009.04.17
 
-using System;
-using System.Collections.Generic;
 using NUnit.Framework;
 using Xtensive.Collections;
 using Xtensive.Core;
@@ -13,7 +11,6 @@
 using Xtensive.Modelling.Actions;
 using Xtensive.Modelling.Comparison;
 using Xtensive.Modelling.Comparison.Hints;
-using System.Linq;
 using Xtensive.Orm.Tests.Core.Modelling.IndexingModel;
 
 namespace Xtensive.Orm.Tests.Core.Modelling
diff --git a/Orm/Xtensive.Orm.Tests.Core/Parameters/ParametersTest.cs b/Orm/Xtensive.Orm.Tests.Core/Parameters/ParametersTest.cs
index c4a2fca1e..ec00fcde1 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Parameters/ParametersTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Parameters/ParametersTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Kofman
 // Created:    2008.08.18
 
-using System;
 using NUnit.Framework;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm.Tests.Core/Performance/ComparerPerformanceTest.cs b/Orm/Xtensive.Orm.Tests.Core/Performance/ComparerPerformanceTest.cs
index fef2d0af0..a8fa0e168 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Performance/ComparerPerformanceTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Performance/ComparerPerformanceTest.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.01.23
 
-using System;
-using System.Collections.Generic;
 using System.Globalization;
 using NUnit.Framework;
 using Xtensive.Comparison;
diff --git a/Orm/Xtensive.Orm.Tests.Core/Performance/TuplePerformanceTest.cs b/Orm/Xtensive.Orm.Tests.Core/Performance/TuplePerformanceTest.cs
index 8b0d13482..0a05dd682 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Performance/TuplePerformanceTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Performance/TuplePerformanceTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.11.01
 
-using System;
 using NUnit.Framework;
 using Xtensive.Tuples;
 using Tuple = Xtensive.Tuples.Tuple;
diff --git a/Orm/Xtensive.Orm.Tests.Core/Reflection/AttributeHelperTest.cs b/Orm/Xtensive.Orm.Tests.Core/Reflection/AttributeHelperTest.cs
index 54fb8c34b..c657adb65 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Reflection/AttributeHelperTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Reflection/AttributeHelperTest.cs
@@ -4,9 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.08.06
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Linq.Expressions;
 using System.Reflection;
 using NUnit.Framework;
diff --git a/Orm/Xtensive.Orm.Tests.Core/Reflection/DelegateHelperCreateDelegateTest.cs b/Orm/Xtensive.Orm.Tests.Core/Reflection/DelegateHelperCreateDelegateTest.cs
index 596505b3e..57dff7c48 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Reflection/DelegateHelperCreateDelegateTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Reflection/DelegateHelperCreateDelegateTest.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.02.09
 
-using System;
-using System.Collections.Generic;
 using NUnit.Framework;
 using Xtensive.Comparison;
 using Xtensive.Collections;
diff --git a/Orm/Xtensive.Orm.Tests.Core/Reflection/TypeHelperGetGenericInterfaceTests.cs b/Orm/Xtensive.Orm.Tests.Core/Reflection/TypeHelperGetGenericInterfaceTests.cs
index f33bd8948..d01fee0e4 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Reflection/TypeHelperGetGenericInterfaceTests.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Reflection/TypeHelperGetGenericInterfaceTests.cs
@@ -2,8 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Collections.Generic;
 using NUnit.Framework;
 using Xtensive.Reflection;
 
diff --git a/Orm/Xtensive.Orm.Tests.Core/Reflection/TypeHelperGetGenericTypeTests.cs b/Orm/Xtensive.Orm.Tests.Core/Reflection/TypeHelperGetGenericTypeTests.cs
index c5302badf..0e363a68b 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Reflection/TypeHelperGetGenericTypeTests.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Reflection/TypeHelperGetGenericTypeTests.cs
@@ -2,8 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Collections.Generic;
 using NUnit.Framework;
 using Xtensive.Reflection;
 
diff --git a/Orm/Xtensive.Orm.Tests.Core/Reflection/TypeHelperTest.cs b/Orm/Xtensive.Orm.Tests.Core/Reflection/TypeHelperTest.cs
index 9ff64c257..4c0455a1f 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Reflection/TypeHelperTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Reflection/TypeHelperTest.cs
@@ -4,9 +4,7 @@
 // Created by: Alex Yakunin
 // Created:    2007.12.17
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
 using System.Collections.Specialized;
 using System.Reflection;
 using NUnit.Framework;
@@ -14,7 +12,6 @@
 using Xtensive.Core;
 using Xtensive.Reflection;
 using Xtensive.Orm.Tests;
-using System.Linq;
 
 namespace Xtensive.Orm.Tests.Core.Reflection
 {
diff --git a/Orm/Xtensive.Orm.Tests.Core/Reflection/TypeHelperTestModel.cs b/Orm/Xtensive.Orm.Tests.Core/Reflection/TypeHelperTestModel.cs
index f664dbab0..2331e6b63 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Reflection/TypeHelperTestModel.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Reflection/TypeHelperTestModel.cs
@@ -4,9 +4,7 @@
 // Created by: Alex Yakunin
 // Created:    2008.01.20
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
 
 namespace Xtensive.Orm.Tests.Core.Reflection
 {
diff --git a/Orm/Xtensive.Orm.Tests.Core/Resources/TestResources.Designer.cs b/Orm/Xtensive.Orm.Tests.Core/Resources/TestResources.Designer.cs
index b282f33bf..1dcadf0c7 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Resources/TestResources.Designer.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Resources/TestResources.Designer.cs
@@ -9,7 +9,6 @@
 //------------------------------------------------------------------------------
 
 namespace Xtensive.Resources {
-    using System;
     
     
     /// <summary>
diff --git a/Orm/Xtensive.Orm.Tests.Core/Testing/InstanceGeneratorTest.cs b/Orm/Xtensive.Orm.Tests.Core/Testing/InstanceGeneratorTest.cs
index 4b49d810c..dca007e5c 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Testing/InstanceGeneratorTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Testing/InstanceGeneratorTest.cs
@@ -4,8 +4,6 @@
 // Created by: Roman Churakov
 // Created:    2008.01.24
 
-using System;
-using System.Collections.Generic;
 using NUnit.Framework;
 using Xtensive.Comparison;
 using Xtensive.Orm.Logging;
diff --git a/Orm/Xtensive.Orm.Tests.Core/Testing/RandomManagerTest.cs b/Orm/Xtensive.Orm.Tests.Core/Testing/RandomManagerTest.cs
index 036575688..7a2ccf6af 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Testing/RandomManagerTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Testing/RandomManagerTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.01.09
 
-using System;
 using System.Runtime.CompilerServices;
 using NUnit.Framework;
 
diff --git a/Orm/Xtensive.Orm.Tests.Core/Tuples/DateTimeOffsetTupleTest.cs b/Orm/Xtensive.Orm.Tests.Core/Tuples/DateTimeOffsetTupleTest.cs
index dea263423..2878e71d4 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Tuples/DateTimeOffsetTupleTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Tuples/DateTimeOffsetTupleTest.cs
@@ -2,9 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Reflection;
 using System.Text;
 using NUnit.Framework;
diff --git a/Orm/Xtensive.Orm.Tests.Core/Tuples/DifferentialTupleTest.cs b/Orm/Xtensive.Orm.Tests.Core/Tuples/DifferentialTupleTest.cs
index a3321301e..3536da4a8 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Tuples/DifferentialTupleTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Tuples/DifferentialTupleTest.cs
@@ -4,7 +4,6 @@
 // Created by: Nick Svetlov
 // Created:    2008.05.23
 
-using System.Collections.Generic;
 using System.Reflection;
 using NUnit.Framework;
 using Xtensive.Orm.Tests;
diff --git a/Orm/Xtensive.Orm.Tests.Core/Tuples/DummyTuple.cs b/Orm/Xtensive.Orm.Tests.Core/Tuples/DummyTuple.cs
index 6a0997aa8..3e0eedc93 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Tuples/DummyTuple.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Tuples/DummyTuple.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2008.01.24
 
-using System;
 using System.Collections;
 using Xtensive.Core;
 using Xtensive.Tuples;
diff --git a/Orm/Xtensive.Orm.Tests.Core/Tuples/LongTupleTest.cs b/Orm/Xtensive.Orm.Tests.Core/Tuples/LongTupleTest.cs
index 91dac3837..615284f56 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Tuples/LongTupleTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Tuples/LongTupleTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2011.04.18
 
-using System;
 using System.Diagnostics;
 using NUnit.Framework;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm.Tests.Core/Tuples/Transform/CutInTransformTest.cs b/Orm/Xtensive.Orm.Tests.Core/Tuples/Transform/CutInTransformTest.cs
index 47c4971b9..1985e02a5 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Tuples/Transform/CutInTransformTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Tuples/Transform/CutInTransformTest.cs
@@ -4,7 +4,6 @@
 // Created by: Elena Vakhtina
 // Created:    2008.06.23
 
-using System;
 using NUnit.Framework;
 using Xtensive.Comparison;
 using Xtensive.Tuples;
diff --git a/Orm/Xtensive.Orm.Tests.Core/Tuples/Transform/MergeTransformTest.cs b/Orm/Xtensive.Orm.Tests.Core/Tuples/Transform/MergeTransformTest.cs
index 96e33fc3a..51380a6b1 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Tuples/Transform/MergeTransformTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Tuples/Transform/MergeTransformTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.06.05
 
-using System;
 using NUnit.Framework;
 using Xtensive.Comparison;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm.Tests.Core/Tuples/Transform/ReadOnlyTransformTest.cs b/Orm/Xtensive.Orm.Tests.Core/Tuples/Transform/ReadOnlyTransformTest.cs
index 83be58a70..1abdd62eb 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Tuples/Transform/ReadOnlyTransformTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Tuples/Transform/ReadOnlyTransformTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.06.05
 
-using System;
 using NUnit.Framework;
 using Xtensive.Comparison;
 using Xtensive.Tuples;
diff --git a/Orm/Xtensive.Orm.Tests.Core/Tuples/Transform/SegmentTransformTest.cs b/Orm/Xtensive.Orm.Tests.Core/Tuples/Transform/SegmentTransformTest.cs
index 3ff89f794..aa438dc55 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Tuples/Transform/SegmentTransformTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Tuples/Transform/SegmentTransformTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.06.05
 
-using System;
 using NUnit.Framework;
 using Xtensive.Comparison;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm.Tests.Core/Tuples/TupleBehaviorTest.cs b/Orm/Xtensive.Orm.Tests.Core/Tuples/TupleBehaviorTest.cs
index c42417c4e..79543a15f 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Tuples/TupleBehaviorTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Tuples/TupleBehaviorTest.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2008.01.24
 
-using System;
 using System.Reflection;
 using NUnit.Framework;
 using Xtensive.Orm.Tests;
diff --git a/Orm/Xtensive.Orm.Tests.Core/Tuples/TupleBehaviorTestBase.cs b/Orm/Xtensive.Orm.Tests.Core/Tuples/TupleBehaviorTestBase.cs
index 1ef1abb0c..1beb058d4 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Tuples/TupleBehaviorTestBase.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Tuples/TupleBehaviorTestBase.cs
@@ -4,9 +4,6 @@
 // Created by: Nick Svetlov
 // Created:    2008.05.23
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Reflection;
 using NUnit.Framework;
 using Xtensive.Tuples;
diff --git a/Orm/Xtensive.Orm.Tests.Core/Tuples/TupleComparerTest.cs b/Orm/Xtensive.Orm.Tests.Core/Tuples/TupleComparerTest.cs
index 57d642c12..62192b9ed 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Tuples/TupleComparerTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Tuples/TupleComparerTest.cs
@@ -4,9 +4,7 @@
 // Created by: Alexey Kochetov
 // Created:    2007.08.23
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
 using NUnit.Framework;
 using Xtensive.Comparison;
 using Xtensive.Orm.Tests;
diff --git a/Orm/Xtensive.Orm.Tests.Core/Tuples/TupleDescriptorTest.cs b/Orm/Xtensive.Orm.Tests.Core/Tuples/TupleDescriptorTest.cs
index c228d2dba..83d83ba5f 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Tuples/TupleDescriptorTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Tuples/TupleDescriptorTest.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.01.25
 
-using System;
-using System.Collections.Generic;
 using NUnit.Framework;
 using Xtensive.Tuples;
 
diff --git a/Orm/Xtensive.Orm.Tests.Core/Tuples/TuplePerformanceTest.cs b/Orm/Xtensive.Orm.Tests.Core/Tuples/TuplePerformanceTest.cs
index 719f6eac7..c15a8ce33 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Tuples/TuplePerformanceTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Tuples/TuplePerformanceTest.cs
@@ -1,7 +1,3 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Threading;
 using NUnit.Framework;
 using Xtensive.Comparison;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm.Tests.Core/Tuples/TupleSerializationTest.cs b/Orm/Xtensive.Orm.Tests.Core/Tuples/TupleSerializationTest.cs
index 324dc06df..c89f0f338 100644
--- a/Orm/Xtensive.Orm.Tests.Core/Tuples/TupleSerializationTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Core/Tuples/TupleSerializationTest.cs
@@ -8,6 +8,7 @@
 using Xtensive.Core;
 using Xtensive.Orm.Tests;
 using Xtensive.Tuples;
+using Tuple = Xtensive.Tuples.Tuple;
 
 namespace Xtensive.Orm.Tests.Core.Tuples
 {
diff --git a/Orm/Xtensive.Orm.Tests.Framework/AssertEx.cs b/Orm/Xtensive.Orm.Tests.Framework/AssertEx.cs
index 8b376ccbe..fa453a8b8 100644
--- a/Orm/Xtensive.Orm.Tests.Framework/AssertEx.cs
+++ b/Orm/Xtensive.Orm.Tests.Framework/AssertEx.cs
@@ -4,9 +4,6 @@
 // Created by: 
 // Created:    2007.10.20
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Text.RegularExpressions;
 using JetBrains.Annotations;
 using NUnit.Framework;
diff --git a/Orm/Xtensive.Orm.Tests.Framework/AutoBuildTest.cs b/Orm/Xtensive.Orm.Tests.Framework/AutoBuildTest.cs
index e44a98544..7faf14aab 100644
--- a/Orm/Xtensive.Orm.Tests.Framework/AutoBuildTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Framework/AutoBuildTest.cs
@@ -6,7 +6,6 @@
 
 using System.Diagnostics;
 using NUnit.Framework;
-using System;
 using Xtensive.Core;
 using Xtensive.Reflection;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests.Framework/DebugInfo.cs b/Orm/Xtensive.Orm.Tests.Framework/DebugInfo.cs
index 9403b681e..81cfaefa9 100644
--- a/Orm/Xtensive.Orm.Tests.Framework/DebugInfo.cs
+++ b/Orm/Xtensive.Orm.Tests.Framework/DebugInfo.cs
@@ -4,9 +4,7 @@
 // Created by: Alex Yakunin
 // Created:    2007.10.03
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
 using System.Diagnostics;
 using System.IO;
 using System.Security;
diff --git a/Orm/Xtensive.Orm.Tests.Framework/DomainModelExtensions.cs b/Orm/Xtensive.Orm.Tests.Framework/DomainModelExtensions.cs
index 56c703f4e..cdb2f5d2f 100644
--- a/Orm/Xtensive.Orm.Tests.Framework/DomainModelExtensions.cs
+++ b/Orm/Xtensive.Orm.Tests.Framework/DomainModelExtensions.cs
@@ -4,9 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2008.06.21
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Core;
 using Xtensive.Orm.Model;
 
diff --git a/Orm/Xtensive.Orm.Tests.Framework/Dynamic.cs b/Orm/Xtensive.Orm.Tests.Framework/Dynamic.cs
index 01ce6463c..da65c1988 100644
--- a/Orm/Xtensive.Orm.Tests.Framework/Dynamic.cs
+++ b/Orm/Xtensive.Orm.Tests.Framework/Dynamic.cs
@@ -1,12 +1,10 @@
 //Copyright (C) Microsoft Corporation.  All rights reserved.
 
-using System.Collections.Generic;
 using System.Globalization;
 using System.Linq.Expressions;
 using System.Reflection;
 using System.Reflection.Emit;
 using System.Text;
-using System.Threading;
 
 namespace System.Linq.Dynamic
 {
diff --git a/Orm/Xtensive.Orm.Tests.Framework/HighResolutionTime.cs b/Orm/Xtensive.Orm.Tests.Framework/HighResolutionTime.cs
index 74aca1db7..260030e72 100644
--- a/Orm/Xtensive.Orm.Tests.Framework/HighResolutionTime.cs
+++ b/Orm/Xtensive.Orm.Tests.Framework/HighResolutionTime.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2007.06.11
 
-using System;
 using System.Diagnostics;
 
 namespace Xtensive.Orm.Tests
diff --git a/Orm/Xtensive.Orm.Tests.Framework/IndexInfoExtensions.cs b/Orm/Xtensive.Orm.Tests.Framework/IndexInfoExtensions.cs
index 3012b11b8..dc2a5cdba 100644
--- a/Orm/Xtensive.Orm.Tests.Framework/IndexInfoExtensions.cs
+++ b/Orm/Xtensive.Orm.Tests.Framework/IndexInfoExtensions.cs
@@ -4,8 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.10.09
 
-using System;
-using System.Linq;
 using Xtensive.Core;
 using Xtensive.Orm.Model;
 
diff --git a/Orm/Xtensive.Orm.Tests.Framework/InheritanceSchemaModifier.cs b/Orm/Xtensive.Orm.Tests.Framework/InheritanceSchemaModifier.cs
index 27af780dc..35bc09299 100644
--- a/Orm/Xtensive.Orm.Tests.Framework/InheritanceSchemaModifier.cs
+++ b/Orm/Xtensive.Orm.Tests.Framework/InheritanceSchemaModifier.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2008.08.05
 
-using System;
 using Xtensive.Orm;
 using Xtensive.Orm.Building;
 using Xtensive.Orm.Building.Definitions;
diff --git a/Orm/Xtensive.Orm.Tests.Framework/InstanceGenerationUtils.cs b/Orm/Xtensive.Orm.Tests.Framework/InstanceGenerationUtils.cs
index 630a5fa22..41ad5195a 100644
--- a/Orm/Xtensive.Orm.Tests.Framework/InstanceGenerationUtils.cs
+++ b/Orm/Xtensive.Orm.Tests.Framework/InstanceGenerationUtils.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.02.12
 
-using System;
-using System.Collections.Generic;
 using Xtensive.Core;
 
 namespace Xtensive.Orm.Tests
diff --git a/Orm/Xtensive.Orm.Tests.Framework/InstanceGeneratorProvider.cs b/Orm/Xtensive.Orm.Tests.Framework/InstanceGeneratorProvider.cs
index 89fea6a73..806e114d9 100644
--- a/Orm/Xtensive.Orm.Tests.Framework/InstanceGeneratorProvider.cs
+++ b/Orm/Xtensive.Orm.Tests.Framework/InstanceGeneratorProvider.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2008.01.17
 
-using System;
 using System.Collections.Concurrent;
 using System.Diagnostics;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm.Tests.Framework/Interfaces/IInstanceGenerator.cs b/Orm/Xtensive.Orm.Tests.Framework/Interfaces/IInstanceGenerator.cs
index 7efff9b4e..b592cab5f 100644
--- a/Orm/Xtensive.Orm.Tests.Framework/Interfaces/IInstanceGenerator.cs
+++ b/Orm/Xtensive.Orm.Tests.Framework/Interfaces/IInstanceGenerator.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2008.01.16
 
-using System;
-using System.Collections.Generic;
 
 namespace Xtensive.Orm.Tests
 {
diff --git a/Orm/Xtensive.Orm.Tests.Framework/Interfaces/IInstanceGeneratorBase.cs b/Orm/Xtensive.Orm.Tests.Framework/Interfaces/IInstanceGeneratorBase.cs
index 756e92199..4633601d8 100644
--- a/Orm/Xtensive.Orm.Tests.Framework/Interfaces/IInstanceGeneratorBase.cs
+++ b/Orm/Xtensive.Orm.Tests.Framework/Interfaces/IInstanceGeneratorBase.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.03.07
 
-using System;
 using System.Collections;
 
 namespace Xtensive.Orm.Tests
diff --git a/Orm/Xtensive.Orm.Tests.Framework/Interfaces/IInstanceGeneratorProvider.cs b/Orm/Xtensive.Orm.Tests.Framework/Interfaces/IInstanceGeneratorProvider.cs
index 5e10b3bab..7b4b064bc 100644
--- a/Orm/Xtensive.Orm.Tests.Framework/Interfaces/IInstanceGeneratorProvider.cs
+++ b/Orm/Xtensive.Orm.Tests.Framework/Interfaces/IInstanceGeneratorProvider.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2008.01.21
 
-using System;
 
 namespace Xtensive.Orm.Tests
 {
diff --git a/Orm/Xtensive.Orm.Tests.Framework/Interfaces/IStorageTimeZoneProvider.cs b/Orm/Xtensive.Orm.Tests.Framework/Interfaces/IStorageTimeZoneProvider.cs
index c8ab06089..9e184bb0c 100644
--- a/Orm/Xtensive.Orm.Tests.Framework/Interfaces/IStorageTimeZoneProvider.cs
+++ b/Orm/Xtensive.Orm.Tests.Framework/Interfaces/IStorageTimeZoneProvider.cs
@@ -2,7 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
 
 namespace Xtensive.Orm.Tests
 {
diff --git a/Orm/Xtensive.Orm.Tests.Framework/Internals/ArrayInstanceGenerator.cs b/Orm/Xtensive.Orm.Tests.Framework/Internals/ArrayInstanceGenerator.cs
index 44cc5d960..ab9821225 100644
--- a/Orm/Xtensive.Orm.Tests.Framework/Internals/ArrayInstanceGenerator.cs
+++ b/Orm/Xtensive.Orm.Tests.Framework/Internals/ArrayInstanceGenerator.cs
@@ -5,8 +5,6 @@
 // Created:    2008.01.25
 
 
-using System;
-using System.Collections.Generic;
 
 namespace Xtensive.Orm.Tests
 {
diff --git a/Orm/Xtensive.Orm.Tests.Framework/Internals/BooleanInstanceGenerator.cs b/Orm/Xtensive.Orm.Tests.Framework/Internals/BooleanInstanceGenerator.cs
index 744082c6b..e14e1e9b2 100644
--- a/Orm/Xtensive.Orm.Tests.Framework/Internals/BooleanInstanceGenerator.cs
+++ b/Orm/Xtensive.Orm.Tests.Framework/Internals/BooleanInstanceGenerator.cs
@@ -5,7 +5,6 @@
 // Created:    2008.01.18
 
 
-using System;
 
 namespace Xtensive.Orm.Tests
 {
diff --git a/Orm/Xtensive.Orm.Tests.Framework/Internals/ByteInstanceGenerator.cs b/Orm/Xtensive.Orm.Tests.Framework/Internals/ByteInstanceGenerator.cs
index 211add9df..0fb4dfa1d 100644
--- a/Orm/Xtensive.Orm.Tests.Framework/Internals/ByteInstanceGenerator.cs
+++ b/Orm/Xtensive.Orm.Tests.Framework/Internals/ByteInstanceGenerator.cs
@@ -5,7 +5,6 @@
 // Created:    2008.01.18
 
 
-using System;
 
 namespace Xtensive.Orm.Tests
 {
diff --git a/Orm/Xtensive.Orm.Tests.Framework/Internals/CharInstanceGenerator.cs b/Orm/Xtensive.Orm.Tests.Framework/Internals/CharInstanceGenerator.cs
index 07df3e293..3b4f10b98 100644
--- a/Orm/Xtensive.Orm.Tests.Framework/Internals/CharInstanceGenerator.cs
+++ b/Orm/Xtensive.Orm.Tests.Framework/Internals/CharInstanceGenerator.cs
@@ -5,7 +5,6 @@
 // Created:    2008.01.18
 
 
-using System;
 
 namespace Xtensive.Orm.Tests
 {
diff --git a/Orm/Xtensive.Orm.Tests.Framework/Internals/DateTimeInstanceGenerator.cs b/Orm/Xtensive.Orm.Tests.Framework/Internals/DateTimeInstanceGenerator.cs
index bafd78754..9727b7396 100644
--- a/Orm/Xtensive.Orm.Tests.Framework/Internals/DateTimeInstanceGenerator.cs
+++ b/Orm/Xtensive.Orm.Tests.Framework/Internals/DateTimeInstanceGenerator.cs
@@ -5,7 +5,6 @@
 // Created:    2008.01.22
 
 
-using System;
 
 namespace Xtensive.Orm.Tests
 {
diff --git a/Orm/Xtensive.Orm.Tests.Framework/Internals/DateTimeOffsetInstanceGenerator.cs b/Orm/Xtensive.Orm.Tests.Framework/Internals/DateTimeOffsetInstanceGenerator.cs
index e71e81592..99072d600 100644
--- a/Orm/Xtensive.Orm.Tests.Framework/Internals/DateTimeOffsetInstanceGenerator.cs
+++ b/Orm/Xtensive.Orm.Tests.Framework/Internals/DateTimeOffsetInstanceGenerator.cs
@@ -2,7 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
 
 namespace Xtensive.Orm.Tests
 {
diff --git a/Orm/Xtensive.Orm.Tests.Framework/Internals/DecimalInstanceGenerator.cs b/Orm/Xtensive.Orm.Tests.Framework/Internals/DecimalInstanceGenerator.cs
index 211159831..a7de52903 100644
--- a/Orm/Xtensive.Orm.Tests.Framework/Internals/DecimalInstanceGenerator.cs
+++ b/Orm/Xtensive.Orm.Tests.Framework/Internals/DecimalInstanceGenerator.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2008.01.24
 
-using System;
 
 namespace Xtensive.Orm.Tests
 {
diff --git a/Orm/Xtensive.Orm.Tests.Framework/Internals/DoubleInstanceGenerator.cs b/Orm/Xtensive.Orm.Tests.Framework/Internals/DoubleInstanceGenerator.cs
index 25af52d41..3d8d934d0 100644
--- a/Orm/Xtensive.Orm.Tests.Framework/Internals/DoubleInstanceGenerator.cs
+++ b/Orm/Xtensive.Orm.Tests.Framework/Internals/DoubleInstanceGenerator.cs
@@ -5,7 +5,6 @@
 // Created:    2008.01.18
 
 
-using System;
 
 namespace Xtensive.Orm.Tests
 {
diff --git a/Orm/Xtensive.Orm.Tests.Framework/Internals/EnumInstanceGenerator.cs b/Orm/Xtensive.Orm.Tests.Framework/Internals/EnumInstanceGenerator.cs
index d401809c2..8a139f9b6 100644
--- a/Orm/Xtensive.Orm.Tests.Framework/Internals/EnumInstanceGenerator.cs
+++ b/Orm/Xtensive.Orm.Tests.Framework/Internals/EnumInstanceGenerator.cs
@@ -5,7 +5,6 @@
 // Created:    2008.01.23
 
 
-using System;
 
 namespace Xtensive.Orm.Tests
 {
diff --git a/Orm/Xtensive.Orm.Tests.Framework/Internals/GuidInstanceGenerator.cs b/Orm/Xtensive.Orm.Tests.Framework/Internals/GuidInstanceGenerator.cs
index 7d0d3743b..a9d17068b 100644
--- a/Orm/Xtensive.Orm.Tests.Framework/Internals/GuidInstanceGenerator.cs
+++ b/Orm/Xtensive.Orm.Tests.Framework/Internals/GuidInstanceGenerator.cs
@@ -5,7 +5,6 @@
 // Created:    2008.01.22
 
 
-using System;
 
 namespace Xtensive.Orm.Tests
 {
diff --git a/Orm/Xtensive.Orm.Tests.Framework/Internals/InstanceGeneratorBase.cs b/Orm/Xtensive.Orm.Tests.Framework/Internals/InstanceGeneratorBase.cs
index d51ce30d3..1a737214f 100644
--- a/Orm/Xtensive.Orm.Tests.Framework/Internals/InstanceGeneratorBase.cs
+++ b/Orm/Xtensive.Orm.Tests.Framework/Internals/InstanceGeneratorBase.cs
@@ -4,9 +4,7 @@
 // Created by: Alexey Gamzov
 // Created:    2008.01.21
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
 using System.Diagnostics;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm.Tests.Framework/Internals/Int16InstanceGenerator.cs b/Orm/Xtensive.Orm.Tests.Framework/Internals/Int16InstanceGenerator.cs
index c2b638adf..b7d3cf793 100644
--- a/Orm/Xtensive.Orm.Tests.Framework/Internals/Int16InstanceGenerator.cs
+++ b/Orm/Xtensive.Orm.Tests.Framework/Internals/Int16InstanceGenerator.cs
@@ -5,7 +5,6 @@
 // Created:    2008.01.18
 
 
-using System;
 
 namespace Xtensive.Orm.Tests
 {
diff --git a/Orm/Xtensive.Orm.Tests.Framework/Internals/Int32InstanceGenerator.cs b/Orm/Xtensive.Orm.Tests.Framework/Internals/Int32InstanceGenerator.cs
index 8c79942cb..277a8b876 100644
--- a/Orm/Xtensive.Orm.Tests.Framework/Internals/Int32InstanceGenerator.cs
+++ b/Orm/Xtensive.Orm.Tests.Framework/Internals/Int32InstanceGenerator.cs
@@ -5,7 +5,6 @@
 // Created:    2008.01.18
 
 
-using System;
 
 namespace Xtensive.Orm.Tests
 {
diff --git a/Orm/Xtensive.Orm.Tests.Framework/Internals/Int64InstanceGenerator.cs b/Orm/Xtensive.Orm.Tests.Framework/Internals/Int64InstanceGenerator.cs
index 5810ab70f..f43298eb8 100644
--- a/Orm/Xtensive.Orm.Tests.Framework/Internals/Int64InstanceGenerator.cs
+++ b/Orm/Xtensive.Orm.Tests.Framework/Internals/Int64InstanceGenerator.cs
@@ -5,7 +5,6 @@
 // Created:    2008.01.18
 
 
-using System;
 
 namespace Xtensive.Orm.Tests
 {
diff --git a/Orm/Xtensive.Orm.Tests.Framework/Internals/KeyValuePairInstanceGenerator.cs b/Orm/Xtensive.Orm.Tests.Framework/Internals/KeyValuePairInstanceGenerator.cs
index f8e5d0be4..980e11c04 100644
--- a/Orm/Xtensive.Orm.Tests.Framework/Internals/KeyValuePairInstanceGenerator.cs
+++ b/Orm/Xtensive.Orm.Tests.Framework/Internals/KeyValuePairInstanceGenerator.cs
@@ -5,8 +5,6 @@
 // Created:    2008.01.25
 
 
-using System;
-using System.Collections.Generic;
 
 namespace Xtensive.Orm.Tests
 {
diff --git a/Orm/Xtensive.Orm.Tests.Framework/Internals/NullableInstanceGenerator.cs b/Orm/Xtensive.Orm.Tests.Framework/Internals/NullableInstanceGenerator.cs
index f895aa9fe..669e16363 100644
--- a/Orm/Xtensive.Orm.Tests.Framework/Internals/NullableInstanceGenerator.cs
+++ b/Orm/Xtensive.Orm.Tests.Framework/Internals/NullableInstanceGenerator.cs
@@ -5,7 +5,6 @@
 // Created:    2008.01.23
 
 
-using System;
 
 namespace Xtensive.Orm.Tests
 {
diff --git a/Orm/Xtensive.Orm.Tests.Framework/Internals/PairInstanceGenerator.cs b/Orm/Xtensive.Orm.Tests.Framework/Internals/PairInstanceGenerator.cs
index 7727f29a8..45fb6ca66 100644
--- a/Orm/Xtensive.Orm.Tests.Framework/Internals/PairInstanceGenerator.cs
+++ b/Orm/Xtensive.Orm.Tests.Framework/Internals/PairInstanceGenerator.cs
@@ -5,7 +5,6 @@
 // Created:    2008.01.25
 
 
-using System;
 using Xtensive.Core;
 
 namespace Xtensive.Orm.Tests
diff --git a/Orm/Xtensive.Orm.Tests.Framework/Internals/SByteInstanceGenerator.cs b/Orm/Xtensive.Orm.Tests.Framework/Internals/SByteInstanceGenerator.cs
index 0d6f8c686..68cdd2b7a 100644
--- a/Orm/Xtensive.Orm.Tests.Framework/Internals/SByteInstanceGenerator.cs
+++ b/Orm/Xtensive.Orm.Tests.Framework/Internals/SByteInstanceGenerator.cs
@@ -5,7 +5,6 @@
 // Created:    2008.01.18
 
 
-using System;
 
 namespace Xtensive.Orm.Tests
 {
diff --git a/Orm/Xtensive.Orm.Tests.Framework/Internals/SingleInstanceGenerator.cs b/Orm/Xtensive.Orm.Tests.Framework/Internals/SingleInstanceGenerator.cs
index fdbaac755..adb61c9d9 100644
--- a/Orm/Xtensive.Orm.Tests.Framework/Internals/SingleInstanceGenerator.cs
+++ b/Orm/Xtensive.Orm.Tests.Framework/Internals/SingleInstanceGenerator.cs
@@ -5,7 +5,6 @@
 // Created:    2008.01.18
 
 
-using System;
 
 namespace Xtensive.Orm.Tests
 {
diff --git a/Orm/Xtensive.Orm.Tests.Framework/Internals/StringInstanceGenerator.cs b/Orm/Xtensive.Orm.Tests.Framework/Internals/StringInstanceGenerator.cs
index 9800e7ca3..c28f77495 100644
--- a/Orm/Xtensive.Orm.Tests.Framework/Internals/StringInstanceGenerator.cs
+++ b/Orm/Xtensive.Orm.Tests.Framework/Internals/StringInstanceGenerator.cs
@@ -5,7 +5,6 @@
 // Created:    2008.01.22
 
 
-using System;
 
 namespace Xtensive.Orm.Tests
 {
diff --git a/Orm/Xtensive.Orm.Tests.Framework/Internals/TupleInstanceGenerator.cs b/Orm/Xtensive.Orm.Tests.Framework/Internals/TupleInstanceGenerator.cs
index ff5ab8e45..2f29555c8 100644
--- a/Orm/Xtensive.Orm.Tests.Framework/Internals/TupleInstanceGenerator.cs
+++ b/Orm/Xtensive.Orm.Tests.Framework/Internals/TupleInstanceGenerator.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2008.01.30
 
-using System;
-using System.Collections.Generic;
 using System.Diagnostics;
 using Xtensive.Tuples;
 using Tuple = Xtensive.Tuples.Tuple;
diff --git a/Orm/Xtensive.Orm.Tests.Framework/Internals/UInt16InstanceGenerator.cs b/Orm/Xtensive.Orm.Tests.Framework/Internals/UInt16InstanceGenerator.cs
index aa9573ebb..644c32438 100644
--- a/Orm/Xtensive.Orm.Tests.Framework/Internals/UInt16InstanceGenerator.cs
+++ b/Orm/Xtensive.Orm.Tests.Framework/Internals/UInt16InstanceGenerator.cs
@@ -5,7 +5,6 @@
 // Created:    2008.01.18
 
 
-using System;
 
 namespace Xtensive.Orm.Tests
 {
diff --git a/Orm/Xtensive.Orm.Tests.Framework/Internals/UInt32InstanceGenerator.cs b/Orm/Xtensive.Orm.Tests.Framework/Internals/UInt32InstanceGenerator.cs
index 82b895543..77872576a 100644
--- a/Orm/Xtensive.Orm.Tests.Framework/Internals/UInt32InstanceGenerator.cs
+++ b/Orm/Xtensive.Orm.Tests.Framework/Internals/UInt32InstanceGenerator.cs
@@ -5,7 +5,6 @@
 // Created:    2008.01.18
 
 
-using System;
 
 namespace Xtensive.Orm.Tests
 {
diff --git a/Orm/Xtensive.Orm.Tests.Framework/Internals/UInt64InstanceGenerator.cs b/Orm/Xtensive.Orm.Tests.Framework/Internals/UInt64InstanceGenerator.cs
index e39c8fbdc..1e0445a8d 100644
--- a/Orm/Xtensive.Orm.Tests.Framework/Internals/UInt64InstanceGenerator.cs
+++ b/Orm/Xtensive.Orm.Tests.Framework/Internals/UInt64InstanceGenerator.cs
@@ -5,7 +5,6 @@
 // Created:    2008.01.18
 
 
-using System;
 
 
 namespace Xtensive.Orm.Tests
diff --git a/Orm/Xtensive.Orm.Tests.Framework/Measurement.cs b/Orm/Xtensive.Orm.Tests.Framework/Measurement.cs
index 8509b7df2..b5e84ac5a 100644
--- a/Orm/Xtensive.Orm.Tests.Framework/Measurement.cs
+++ b/Orm/Xtensive.Orm.Tests.Framework/Measurement.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2007.06.11
 
-using System;
 using System.Diagnostics;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm.Tests.Framework/MeasurementOptions.cs b/Orm/Xtensive.Orm.Tests.Framework/MeasurementOptions.cs
index 5727bd028..48417137f 100644
--- a/Orm/Xtensive.Orm.Tests.Framework/MeasurementOptions.cs
+++ b/Orm/Xtensive.Orm.Tests.Framework/MeasurementOptions.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2007.10.03
 
-using System;
 
 namespace Xtensive.Orm.Tests
 {
diff --git a/Orm/Xtensive.Orm.Tests.Framework/ModelBuildingTest.cs b/Orm/Xtensive.Orm.Tests.Framework/ModelBuildingTest.cs
index 2980757ad..a189a0107 100644
--- a/Orm/Xtensive.Orm.Tests.Framework/ModelBuildingTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Framework/ModelBuildingTest.cs
@@ -4,11 +4,8 @@
 // Created by: Alexey Kulakov
 // Created:    2018.10.01
 
-using System;
-using System.Collections.Generic;
 using System.Collections.ObjectModel;
 using System.Diagnostics;
-using System.Linq;
 using System.Reflection;
 using NUnit.Framework;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm.Tests.Framework/RandomManager.cs b/Orm/Xtensive.Orm.Tests.Framework/RandomManager.cs
index 012c84a6f..145d34c18 100644
--- a/Orm/Xtensive.Orm.Tests.Framework/RandomManager.cs
+++ b/Orm/Xtensive.Orm.Tests.Framework/RandomManager.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.01.09
 
-using System;
 using System.Diagnostics;
 using System.IO;
 using System.Reflection;
diff --git a/Orm/Xtensive.Orm.Tests.Framework/Require.cs b/Orm/Xtensive.Orm.Tests.Framework/Require.cs
index 6d5ccf2f3..e1f3cfe08 100644
--- a/Orm/Xtensive.Orm.Tests.Framework/Require.cs
+++ b/Orm/Xtensive.Orm.Tests.Framework/Require.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2010.02.11
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Providers;
 
diff --git a/Orm/Xtensive.Orm.Tests.Framework/RuntimeInfo.cs b/Orm/Xtensive.Orm.Tests.Framework/RuntimeInfo.cs
index 8af57d240..2797c9a6a 100644
--- a/Orm/Xtensive.Orm.Tests.Framework/RuntimeInfo.cs
+++ b/Orm/Xtensive.Orm.Tests.Framework/RuntimeInfo.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.04.17
 
-using System;
 using System.Diagnostics;
 using System.Runtime.InteropServices;
 
diff --git a/Orm/Xtensive.Orm.Tests.Framework/SeedVariatorType.cs b/Orm/Xtensive.Orm.Tests.Framework/SeedVariatorType.cs
index cc679d992..de56e431d 100644
--- a/Orm/Xtensive.Orm.Tests.Framework/SeedVariatorType.cs
+++ b/Orm/Xtensive.Orm.Tests.Framework/SeedVariatorType.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.01.09
 
-using System;
 
 namespace Xtensive.Orm.Tests
 {
diff --git a/Orm/Xtensive.Orm.Tests.Framework/StorageProvider.cs b/Orm/Xtensive.Orm.Tests.Framework/StorageProvider.cs
index d1e3228b1..be3fb12a9 100644
--- a/Orm/Xtensive.Orm.Tests.Framework/StorageProvider.cs
+++ b/Orm/Xtensive.Orm.Tests.Framework/StorageProvider.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.07.09
 
-using System;
 
 namespace Xtensive.Orm.Tests
 {
diff --git a/Orm/Xtensive.Orm.Tests.Framework/StorageProviderInfo.cs b/Orm/Xtensive.Orm.Tests.Framework/StorageProviderInfo.cs
index 13d3a4022..ae5fb271b 100644
--- a/Orm/Xtensive.Orm.Tests.Framework/StorageProviderInfo.cs
+++ b/Orm/Xtensive.Orm.Tests.Framework/StorageProviderInfo.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2013.07.23
 
-using System;
 using Xtensive.Orm.Providers;
 using Xtensive.Sql;
 
diff --git a/Orm/Xtensive.Orm.Tests.Framework/StorageProviderVersion.cs b/Orm/Xtensive.Orm.Tests.Framework/StorageProviderVersion.cs
index c45858ca4..111e49de7 100644
--- a/Orm/Xtensive.Orm.Tests.Framework/StorageProviderVersion.cs
+++ b/Orm/Xtensive.Orm.Tests.Framework/StorageProviderVersion.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2010.02.11
 
-using System;
 
 namespace Xtensive.Orm.Tests
 {
diff --git a/Orm/Xtensive.Orm.Tests.Framework/StorageTestHelper.cs b/Orm/Xtensive.Orm.Tests.Framework/StorageTestHelper.cs
index 3b9a86d47..df80bf105 100644
--- a/Orm/Xtensive.Orm.Tests.Framework/StorageTestHelper.cs
+++ b/Orm/Xtensive.Orm.Tests.Framework/StorageTestHelper.cs
@@ -4,9 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.12.17
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Orm.Providers;
 using Xtensive.Sql;
 using Xtensive.Sql.Model;
diff --git a/Orm/Xtensive.Orm.Tests.Framework/StorageTimeZoneProvider.cs b/Orm/Xtensive.Orm.Tests.Framework/StorageTimeZoneProvider.cs
index c5c587c42..daa696343 100644
--- a/Orm/Xtensive.Orm.Tests.Framework/StorageTimeZoneProvider.cs
+++ b/Orm/Xtensive.Orm.Tests.Framework/StorageTimeZoneProvider.cs
@@ -2,7 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
 using Xtensive.Sql;
 
 namespace Xtensive.Orm.Tests
diff --git a/Orm/Xtensive.Orm.Tests.Framework/TestConfiguration.cs b/Orm/Xtensive.Orm.Tests.Framework/TestConfiguration.cs
index 835f0088d..c708245f7 100644
--- a/Orm/Xtensive.Orm.Tests.Framework/TestConfiguration.cs
+++ b/Orm/Xtensive.Orm.Tests.Framework/TestConfiguration.cs
@@ -4,10 +4,7 @@
 // Created by: Denis Krjuchkov
 // Created:    2010.02.11
 
-using System;
-using System.Collections.Generic;
 using System.IO;
-using System.Linq;
 
 namespace Xtensive.Orm.Tests
 {
diff --git a/Orm/Xtensive.Orm.Tests.Framework/TestHelper.cs b/Orm/Xtensive.Orm.Tests.Framework/TestHelper.cs
index e53e5398c..7ab95db26 100644
--- a/Orm/Xtensive.Orm.Tests.Framework/TestHelper.cs
+++ b/Orm/Xtensive.Orm.Tests.Framework/TestHelper.cs
@@ -4,9 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.02.09
 
-using System;
-using System.Collections.Generic;
-using System.Threading;
 using Xtensive.Sql.Dml;
 
 
diff --git a/Orm/Xtensive.Orm.Tests.Framework/TestInfo.cs b/Orm/Xtensive.Orm.Tests.Framework/TestInfo.cs
index 799b54c27..faea399ef 100644
--- a/Orm/Xtensive.Orm.Tests.Framework/TestInfo.cs
+++ b/Orm/Xtensive.Orm.Tests.Framework/TestInfo.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.02.09
 
-using System;
-using System.Collections.Generic;
 using System.Diagnostics;
 using System.Reflection;
 using NUnit.Framework;
diff --git a/Orm/Xtensive.Orm.Tests.Framework/TestSqlDriver.cs b/Orm/Xtensive.Orm.Tests.Framework/TestSqlDriver.cs
index ad793b3d9..bdfdd889a 100644
--- a/Orm/Xtensive.Orm.Tests.Framework/TestSqlDriver.cs
+++ b/Orm/Xtensive.Orm.Tests.Framework/TestSqlDriver.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2011.11.04
 
-using System;
-using System.Collections.Generic;
 using Xtensive.Core;
 using Xtensive.Orm.Building.Builders;
 using Xtensive.Sql;
diff --git a/Orm/Xtensive.Orm.Tests.Framework/TypeIdModifier.cs b/Orm/Xtensive.Orm.Tests.Framework/TypeIdModifier.cs
index 22e5b06fb..e82379913 100644
--- a/Orm/Xtensive.Orm.Tests.Framework/TypeIdModifier.cs
+++ b/Orm/Xtensive.Orm.Tests.Framework/TypeIdModifier.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2008.08.05
 
-using System;
 using Xtensive.Orm;
 using Xtensive.Orm.Building;
 using Xtensive.Orm.Building.Definitions;
diff --git a/Orm/Xtensive.Orm.Tests.Framework/WellKnownDatabases.cs b/Orm/Xtensive.Orm.Tests.Framework/WellKnownDatabases.cs
index b08ff6303..ab083832f 100644
--- a/Orm/Xtensive.Orm.Tests.Framework/WellKnownDatabases.cs
+++ b/Orm/Xtensive.Orm.Tests.Framework/WellKnownDatabases.cs
@@ -2,8 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Collections.Generic;
 using System.Text;
 
 namespace Xtensive.Orm.Tests
diff --git a/Orm/Xtensive.Orm.Tests.Framework/WellKnownSchemas.cs b/Orm/Xtensive.Orm.Tests.Framework/WellKnownSchemas.cs
index b9468cd59..ce7b70881 100644
--- a/Orm/Xtensive.Orm.Tests.Framework/WellKnownSchemas.cs
+++ b/Orm/Xtensive.Orm.Tests.Framework/WellKnownSchemas.cs
@@ -2,8 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Collections.Generic;
 using System.Text;
 
 namespace Xtensive.Orm.Tests
diff --git a/Orm/Xtensive.Orm.Tests.Framework/WrappingInstanceGenerator{T,TBase1,TBase2, TBase3}.cs b/Orm/Xtensive.Orm.Tests.Framework/WrappingInstanceGenerator{T,TBase1,TBase2, TBase3}.cs
index 40747900a..6e480362f 100644
--- a/Orm/Xtensive.Orm.Tests.Framework/WrappingInstanceGenerator{T,TBase1,TBase2, TBase3}.cs	
+++ b/Orm/Xtensive.Orm.Tests.Framework/WrappingInstanceGenerator{T,TBase1,TBase2, TBase3}.cs	
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.01.21
 
-using System;
 
 namespace Xtensive.Orm.Tests
 {
diff --git a/Orm/Xtensive.Orm.Tests.Framework/WrappingInstanceGenerator{T,TBase1,TBase2}.cs b/Orm/Xtensive.Orm.Tests.Framework/WrappingInstanceGenerator{T,TBase1,TBase2}.cs
index 2c9fdd653..31b043a96 100644
--- a/Orm/Xtensive.Orm.Tests.Framework/WrappingInstanceGenerator{T,TBase1,TBase2}.cs
+++ b/Orm/Xtensive.Orm.Tests.Framework/WrappingInstanceGenerator{T,TBase1,TBase2}.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.01.21
 
-using System;
 
 namespace Xtensive.Orm.Tests
 {
diff --git a/Orm/Xtensive.Orm.Tests.Framework/WrappingInstanceGenerator{T,TBase}.cs b/Orm/Xtensive.Orm.Tests.Framework/WrappingInstanceGenerator{T,TBase}.cs
index 40529e185..4ecc82589 100644
--- a/Orm/Xtensive.Orm.Tests.Framework/WrappingInstanceGenerator{T,TBase}.cs
+++ b/Orm/Xtensive.Orm.Tests.Framework/WrappingInstanceGenerator{T,TBase}.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.01.21
 
-using System;
 
 namespace Xtensive.Orm.Tests
 {
diff --git a/Orm/Xtensive.Orm.Tests.Sql/ChinookSchemaCreator.cs b/Orm/Xtensive.Orm.Tests.Sql/ChinookSchemaCreator.cs
index 0d0c3897f..6d8884211 100644
--- a/Orm/Xtensive.Orm.Tests.Sql/ChinookSchemaCreator.cs
+++ b/Orm/Xtensive.Orm.Tests.Sql/ChinookSchemaCreator.cs
@@ -4,10 +4,7 @@
 // Created by: Alexey Kulakov
 // Created:    2019.10.03
 
-using System;
-using System.Collections.Generic;
 using System.Globalization;
-using System.Linq;
 using System.Xml.Linq;
 using Xtensive.Sql;
 using Xtensive.Sql.Dml;
diff --git a/Orm/Xtensive.Orm.Tests.Sql/ChinookTestBase.cs b/Orm/Xtensive.Orm.Tests.Sql/ChinookTestBase.cs
index 1a1435ad2..a9a01effa 100644
--- a/Orm/Xtensive.Orm.Tests.Sql/ChinookTestBase.cs
+++ b/Orm/Xtensive.Orm.Tests.Sql/ChinookTestBase.cs
@@ -4,10 +4,8 @@
 // Created by: Malisa Ncube
 // Created:    2011.03.17
 
-using System;
 using System.Data;
 using System.Diagnostics;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Sql;
diff --git a/Orm/Xtensive.Orm.Tests.Sql/CloneTests.cs b/Orm/Xtensive.Orm.Tests.Sql/CloneTests.cs
index 6de9f4081..0b699656d 100644
--- a/Orm/Xtensive.Orm.Tests.Sql/CloneTests.cs
+++ b/Orm/Xtensive.Orm.Tests.Sql/CloneTests.cs
@@ -3,9 +3,6 @@
 // See the License.txt file in the project root for more information.
 
 using NUnit.Framework;
-using System;
-using System.Linq;
-using System.Collections.Generic;
 using Xtensive.Sql;
 using Xtensive.Sql.Dml;
 using Xtensive.Sql.Model;
diff --git a/Orm/Xtensive.Orm.Tests.Sql/CompilerTest.cs b/Orm/Xtensive.Orm.Tests.Sql/CompilerTest.cs
index 63ac0302a..093cb2dda 100644
--- a/Orm/Xtensive.Orm.Tests.Sql/CompilerTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Sql/CompilerTest.cs
@@ -2,8 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Sql;
 using Xtensive.Sql.Ddl;
diff --git a/Orm/Xtensive.Orm.Tests.Sql/DateTimeIntervalTest.cs b/Orm/Xtensive.Orm.Tests.Sql/DateTimeIntervalTest.cs
index d82c29597..039b9a039 100644
--- a/Orm/Xtensive.Orm.Tests.Sql/DateTimeIntervalTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Sql/DateTimeIntervalTest.cs
@@ -5,7 +5,6 @@
 // Created:    2009.02.27
 
 using NUnit.Framework;
-using System;
 using Xtensive.Sql;
 using Xtensive.Sql.Dml;
 
diff --git a/Orm/Xtensive.Orm.Tests.Sql/DateTimeOffsetTest.cs b/Orm/Xtensive.Orm.Tests.Sql/DateTimeOffsetTest.cs
index 608765bfa..168088b1e 100644
--- a/Orm/Xtensive.Orm.Tests.Sql/DateTimeOffsetTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Sql/DateTimeOffsetTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alena Mikshina
 // Created:    2014.01.16
 
-using System;
 using NUnit.Framework;
 using Xtensive.Sql;
 using Xtensive.Sql.Dml;
diff --git a/Orm/Xtensive.Orm.Tests.Sql/DriverFactoryTest.cs b/Orm/Xtensive.Orm.Tests.Sql/DriverFactoryTest.cs
index fc7d5fa95..a7a4d7b76 100644
--- a/Orm/Xtensive.Orm.Tests.Sql/DriverFactoryTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Sql/DriverFactoryTest.cs
@@ -2,15 +2,12 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Orm;
 using Xtensive.Orm.Building.Builders;
 using Xtensive.Sql;
 using Xtensive.Orm.Tests.Sql.DriverFactoryTestTypes;
-using System.Threading.Tasks;
-using System.Threading;
 
 namespace Xtensive.Orm.Tests.Sql.DriverFactoryTestTypes
 {
diff --git a/Orm/Xtensive.Orm.Tests.Sql/ExceptionTypesTest.cs b/Orm/Xtensive.Orm.Tests.Sql/ExceptionTypesTest.cs
index c5e4bc100..4b59f9b35 100644
--- a/Orm/Xtensive.Orm.Tests.Sql/ExceptionTypesTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Sql/ExceptionTypesTest.cs
@@ -4,9 +4,7 @@
 // Created by: Denis Krjuchkov
 // Created:    2010.02.08
 
-using System;
 using System.Data;
-using System.Threading;
 using NUnit.Framework;
 using Xtensive.Sql;
 using Xtensive.Sql.Model;
diff --git a/Orm/Xtensive.Orm.Tests.Sql/ExtractorTestBase.cs b/Orm/Xtensive.Orm.Tests.Sql/ExtractorTestBase.cs
index 41e6db234..adc108e3e 100644
--- a/Orm/Xtensive.Orm.Tests.Sql/ExtractorTestBase.cs
+++ b/Orm/Xtensive.Orm.Tests.Sql/ExtractorTestBase.cs
@@ -2,9 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Text;
 using Microsoft.VisualBasic;
 using NUnit.Framework;
diff --git a/Orm/Xtensive.Orm.Tests.Sql/Firebird/ChinookTest.cs b/Orm/Xtensive.Orm.Tests.Sql/Firebird/ChinookTest.cs
index 99c199882..b7aac3c6e 100644
--- a/Orm/Xtensive.Orm.Tests.Sql/Firebird/ChinookTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Sql/Firebird/ChinookTest.cs
@@ -2,7 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
 using System.Data.Common;
 using NUnit.Framework;
 using Xtensive.Sql;
diff --git a/Orm/Xtensive.Orm.Tests.Sql/Firebird/ExtractorTest.cs b/Orm/Xtensive.Orm.Tests.Sql/Firebird/ExtractorTest.cs
index 96f6971d0..ecc2609b0 100644
--- a/Orm/Xtensive.Orm.Tests.Sql/Firebird/ExtractorTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Sql/Firebird/ExtractorTest.cs
@@ -5,7 +5,6 @@
 // Created:    2011.01.13
 
 using NUnit.Framework;
-using System;
 using System.Text;
 using Xtensive.Sql;
 
diff --git a/Orm/Xtensive.Orm.Tests.Sql/Firebird/QueryTest.cs b/Orm/Xtensive.Orm.Tests.Sql/Firebird/QueryTest.cs
index c3e19b499..52025febe 100644
--- a/Orm/Xtensive.Orm.Tests.Sql/Firebird/QueryTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Sql/Firebird/QueryTest.cs
@@ -1,4 +1,3 @@
-using System;
 using NUnit.Framework;
 using Xtensive.Sql;
 
diff --git a/Orm/Xtensive.Orm.Tests.Sql/Firebird/SavepointTest.cs b/Orm/Xtensive.Orm.Tests.Sql/Firebird/SavepointTest.cs
index d8ffd9355..89fb62f46 100644
--- a/Orm/Xtensive.Orm.Tests.Sql/Firebird/SavepointTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Sql/Firebird/SavepointTest.cs
@@ -5,7 +5,6 @@
 // Created:    2011.01.21
 
 using NUnit.Framework;
-using System;
 
 namespace Xtensive.Orm.Tests.Sql.Firebird
 {
diff --git a/Orm/Xtensive.Orm.Tests.Sql/Firebird/TestHelpers.cs b/Orm/Xtensive.Orm.Tests.Sql/Firebird/TestHelpers.cs
index 8cf1ea0d9..d01924507 100644
--- a/Orm/Xtensive.Orm.Tests.Sql/Firebird/TestHelpers.cs
+++ b/Orm/Xtensive.Orm.Tests.Sql/Firebird/TestHelpers.cs
@@ -6,8 +6,6 @@
 
 using System.Data.Common;
 using System.Diagnostics;
-using System.Collections.Generic;
-using System;
 
 namespace Xtensive.Orm.Tests.Sql.Firebird
 {
diff --git a/Orm/Xtensive.Orm.Tests.Sql/IndexTest.cs b/Orm/Xtensive.Orm.Tests.Sql/IndexTest.cs
index 77b6d6614..8d047e19a 100644
--- a/Orm/Xtensive.Orm.Tests.Sql/IndexTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Sql/IndexTest.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2009.08.31
 
-using System;
 using NUnit.Framework;
 using Xtensive.Sql;
 using Xtensive.Sql.Dml;
diff --git a/Orm/Xtensive.Orm.Tests.Sql/MakeNamesUnreadableTest.cs b/Orm/Xtensive.Orm.Tests.Sql/MakeNamesUnreadableTest.cs
index 8d58a7642..c53622cb5 100644
--- a/Orm/Xtensive.Orm.Tests.Sql/MakeNamesUnreadableTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Sql/MakeNamesUnreadableTest.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2017.03.24
 
-using System;
-using System.Collections.Generic;
 using NUnit.Framework;
 using Xtensive.Sql;
 using Xtensive.Sql.Compiler;
diff --git a/Orm/Xtensive.Orm.Tests.Sql/MySQL/ChinookTest.cs b/Orm/Xtensive.Orm.Tests.Sql/MySQL/ChinookTest.cs
index 41ee3c306..736c63e2a 100644
--- a/Orm/Xtensive.Orm.Tests.Sql/MySQL/ChinookTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Sql/MySQL/ChinookTest.cs
@@ -2,7 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
 using System.Data.Common;
 using NUnit.Framework;
 using Xtensive.Sql;
diff --git a/Orm/Xtensive.Orm.Tests.Sql/MySQL/DateTimeIntervalTests.cs b/Orm/Xtensive.Orm.Tests.Sql/MySQL/DateTimeIntervalTests.cs
index bb41093cb..4111d849e 100644
--- a/Orm/Xtensive.Orm.Tests.Sql/MySQL/DateTimeIntervalTests.cs
+++ b/Orm/Xtensive.Orm.Tests.Sql/MySQL/DateTimeIntervalTests.cs
@@ -4,7 +4,6 @@
 // Created by: Malisa Ncube
 // Created:    2011.03.22
 
-using System;
 using System.Data;
 using System.Data.Common;
 using System.Diagnostics;
diff --git a/Orm/Xtensive.Orm.Tests.Sql/MySQL/MiscTests.cs b/Orm/Xtensive.Orm.Tests.Sql/MySQL/MiscTests.cs
index aac4cc770..da9aa20ad 100644
--- a/Orm/Xtensive.Orm.Tests.Sql/MySQL/MiscTests.cs
+++ b/Orm/Xtensive.Orm.Tests.Sql/MySQL/MiscTests.cs
@@ -4,13 +4,10 @@
 // Created by: Malisa Ncube
 // Created:    2011.03.17
 
-using System;
-using System.Collections.Generic;
 using System.Data;
 using System.Data.Common;
 using System.Diagnostics;
 using System.IO;
-using System.Linq;
 using System.Runtime.Serialization.Formatters.Binary;
 using System.Text;
 using NUnit.Framework;
diff --git a/Orm/Xtensive.Orm.Tests.Sql/MySQL/Sakila.cs b/Orm/Xtensive.Orm.Tests.Sql/MySQL/Sakila.cs
index 29da0c9d3..dabf781bc 100644
--- a/Orm/Xtensive.Orm.Tests.Sql/MySQL/Sakila.cs
+++ b/Orm/Xtensive.Orm.Tests.Sql/MySQL/Sakila.cs
@@ -4,11 +4,8 @@
 // Created by: Malisa Ncube
 // Created:    2011.03.17
 
-using System;
-using System.Collections.Generic;
 using System.Data;
 using System.IO;
-using System.Linq;
 using System.Text;
 using NUnit.Framework;
 using Xtensive.Sql;
diff --git a/Orm/Xtensive.Orm.Tests.Sql/MySQL/SakilaExtractorTest.cs b/Orm/Xtensive.Orm.Tests.Sql/MySQL/SakilaExtractorTest.cs
index 1edcd2ff6..6a460ea33 100644
--- a/Orm/Xtensive.Orm.Tests.Sql/MySQL/SakilaExtractorTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Sql/MySQL/SakilaExtractorTest.cs
@@ -4,7 +4,6 @@
 // Created by: Malisa Ncube
 // Created:    2011.02.25
 
-using System;
 using System.Data;
 using System.Data.Common;
 using System.Diagnostics;
diff --git a/Orm/Xtensive.Orm.Tests.Sql/MySQL/TypeMappingTests.cs b/Orm/Xtensive.Orm.Tests.Sql/MySQL/TypeMappingTests.cs
index 41792b23a..edeccbe84 100644
--- a/Orm/Xtensive.Orm.Tests.Sql/MySQL/TypeMappingTests.cs
+++ b/Orm/Xtensive.Orm.Tests.Sql/MySQL/TypeMappingTests.cs
@@ -4,9 +4,6 @@
 // Created by: Malisa Ncube
 // Created:    2011.03.23
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Text;
 using NUnit.Framework;
 using Xtensive.Orm.Tests.Sql;
diff --git a/Orm/Xtensive.Orm.Tests.Sql/Oracle/ChinookTest.cs b/Orm/Xtensive.Orm.Tests.Sql/Oracle/ChinookTest.cs
index a9a62214c..4e7da2e4d 100644
--- a/Orm/Xtensive.Orm.Tests.Sql/Oracle/ChinookTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Sql/Oracle/ChinookTest.cs
@@ -2,7 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
 using System.Data.Common;
 using NUnit.Framework;
 using Xtensive.Sql;
diff --git a/Orm/Xtensive.Orm.Tests.Sql/Oracle/ExtractorTest.cs b/Orm/Xtensive.Orm.Tests.Sql/Oracle/ExtractorTest.cs
index 72dc96c2e..69d61945d 100644
--- a/Orm/Xtensive.Orm.Tests.Sql/Oracle/ExtractorTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Sql/Oracle/ExtractorTest.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.07.29
 
-using System;
 using System.Text;
 using NUnit.Framework;
 using Xtensive.Sql;
diff --git a/Orm/Xtensive.Orm.Tests.Sql/Oracle/UberTest.cs b/Orm/Xtensive.Orm.Tests.Sql/Oracle/UberTest.cs
index 23e9bd575..be05a8d24 100644
--- a/Orm/Xtensive.Orm.Tests.Sql/Oracle/UberTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Sql/Oracle/UberTest.cs
@@ -4,9 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.07.21
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Sql;
 using Xtensive.Sql.Dml;
diff --git a/Orm/Xtensive.Orm.Tests.Sql/PostgreSql/CatalogComparer.cs b/Orm/Xtensive.Orm.Tests.Sql/PostgreSql/CatalogComparer.cs
index 279200e8f..9307ea1c7 100644
--- a/Orm/Xtensive.Orm.Tests.Sql/PostgreSql/CatalogComparer.cs
+++ b/Orm/Xtensive.Orm.Tests.Sql/PostgreSql/CatalogComparer.cs
@@ -2,8 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Collections.Generic;
 using NUnit.Framework;
 using Xtensive.Sql;
 using Xtensive.Sql.Model;
diff --git a/Orm/Xtensive.Orm.Tests.Sql/PostgreSql/ChinookTest.cs b/Orm/Xtensive.Orm.Tests.Sql/PostgreSql/ChinookTest.cs
index fb0ef3e32..736283247 100644
--- a/Orm/Xtensive.Orm.Tests.Sql/PostgreSql/ChinookTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Sql/PostgreSql/ChinookTest.cs
@@ -2,7 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
 using System.Data.Common;
 using NUnit.Framework;
 using Xtensive.Sql;
diff --git a/Orm/Xtensive.Orm.Tests.Sql/PostgreSql/IndexTest.cs b/Orm/Xtensive.Orm.Tests.Sql/PostgreSql/IndexTest.cs
index 9aad5574b..4d282b8d7 100644
--- a/Orm/Xtensive.Orm.Tests.Sql/PostgreSql/IndexTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Sql/PostgreSql/IndexTest.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2009.08.31
 
-using System;
 using NUnit.Framework;
 using Xtensive.Sql;
 using Xtensive.Sql.Dml;
diff --git a/Orm/Xtensive.Orm.Tests.Sql/PostgreSql/NpgsqlTypeConstructorTest.cs b/Orm/Xtensive.Orm.Tests.Sql/PostgreSql/NpgsqlTypeConstructorTest.cs
index 36037d4c6..aab46a7ca 100644
--- a/Orm/Xtensive.Orm.Tests.Sql/PostgreSql/NpgsqlTypeConstructorTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Sql/PostgreSql/NpgsqlTypeConstructorTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alena Mikshina
 // Created:    2014.05.14
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Providers.PostgreSql;
 using Xtensive.Sql;
diff --git a/Orm/Xtensive.Orm.Tests.Sql/PostgreSql/SqlDomTests.cs b/Orm/Xtensive.Orm.Tests.Sql/PostgreSql/SqlDomTests.cs
index 10e5154b1..69826fecb 100644
--- a/Orm/Xtensive.Orm.Tests.Sql/PostgreSql/SqlDomTests.cs
+++ b/Orm/Xtensive.Orm.Tests.Sql/PostgreSql/SqlDomTests.cs
@@ -2,7 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
 using System.Data;
 using System.Data.Common;
 using NUnit.Framework;
diff --git a/Orm/Xtensive.Orm.Tests.Sql/ReplaceTests.cs b/Orm/Xtensive.Orm.Tests.Sql/ReplaceTests.cs
index bad15106f..f7b9f4117 100644
--- a/Orm/Xtensive.Orm.Tests.Sql/ReplaceTests.cs
+++ b/Orm/Xtensive.Orm.Tests.Sql/ReplaceTests.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System.Collections.Generic;
 using NUnit.Framework;
 using Xtensive.Sql;
 using Xtensive.Sql.Dml;
diff --git a/Orm/Xtensive.Orm.Tests.Sql/SavepointsTest.cs b/Orm/Xtensive.Orm.Tests.Sql/SavepointsTest.cs
index c9b4b33b5..456fd58c2 100644
--- a/Orm/Xtensive.Orm.Tests.Sql/SavepointsTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Sql/SavepointsTest.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.11.20
 
-using System;
 using NUnit.Framework;
 using Xtensive.Sql;
 using Xtensive.Sql.Dml;
diff --git a/Orm/Xtensive.Orm.Tests.Sql/SqlDateTimePartsTest.cs b/Orm/Xtensive.Orm.Tests.Sql/SqlDateTimePartsTest.cs
index 9adc0a8b9..049cc2c90 100644
--- a/Orm/Xtensive.Orm.Tests.Sql/SqlDateTimePartsTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Sql/SqlDateTimePartsTest.cs
@@ -2,9 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Reflection;
 using NUnit.Framework;
 using Xtensive.Sql.Dml;
diff --git a/Orm/Xtensive.Orm.Tests.Sql/SqlHelperQuotationTest.cs b/Orm/Xtensive.Orm.Tests.Sql/SqlHelperQuotationTest.cs
index 5e466ec3a..27bab6faa 100644
--- a/Orm/Xtensive.Orm.Tests.Sql/SqlHelperQuotationTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Sql/SqlHelperQuotationTest.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2020.04.23
 
-using System;
-using System.Collections.Generic;
 using System.Text;
 using NUnit.Framework;
 using Xtensive.Sql;
diff --git a/Orm/Xtensive.Orm.Tests.Sql/SqlInsertTest.cs b/Orm/Xtensive.Orm.Tests.Sql/SqlInsertTest.cs
index 97be5f673..5c803a87e 100644
--- a/Orm/Xtensive.Orm.Tests.Sql/SqlInsertTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Sql/SqlInsertTest.cs
@@ -2,8 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Collections.Generic;
 using NUnit.Framework;
 using Xtensive.Sql;
 using Xtensive.Sql.Dml;
diff --git a/Orm/Xtensive.Orm.Tests.Sql/SqlServer/AdventureWorks.cs b/Orm/Xtensive.Orm.Tests.Sql/SqlServer/AdventureWorks.cs
index a6558fe1c..169f7d81e 100644
--- a/Orm/Xtensive.Orm.Tests.Sql/SqlServer/AdventureWorks.cs
+++ b/Orm/Xtensive.Orm.Tests.Sql/SqlServer/AdventureWorks.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using System.Data;
 using NUnit.Framework;
 using Xtensive.Sql;
diff --git a/Orm/Xtensive.Orm.Tests.Sql/SqlServer/CompilerTests.cs b/Orm/Xtensive.Orm.Tests.Sql/SqlServer/CompilerTests.cs
index 006fe88e3..2b7aa2e4d 100644
--- a/Orm/Xtensive.Orm.Tests.Sql/SqlServer/CompilerTests.cs
+++ b/Orm/Xtensive.Orm.Tests.Sql/SqlServer/CompilerTests.cs
@@ -2,9 +2,7 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System.Collections.Generic;
 using NUnit.Framework;
-using System;
 using System.Data;
 using System.Data.Common;
 using Xtensive.Sql;
diff --git a/Orm/Xtensive.Orm.Tests.Sql/SqlServer/ConnectionTest.cs b/Orm/Xtensive.Orm.Tests.Sql/SqlServer/ConnectionTest.cs
index 5015b6351..d1045555d 100644
--- a/Orm/Xtensive.Orm.Tests.Sql/SqlServer/ConnectionTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Sql/SqlServer/ConnectionTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2018.10.30
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Building.Builders;
 using Xtensive.Sql;
diff --git a/Orm/Xtensive.Orm.Tests.Sql/SqlServer/ErrorMessageParserTest.cs b/Orm/Xtensive.Orm.Tests.Sql/SqlServer/ErrorMessageParserTest.cs
index 7ed3a0297..a56697555 100644
--- a/Orm/Xtensive.Orm.Tests.Sql/SqlServer/ErrorMessageParserTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Sql/SqlServer/ErrorMessageParserTest.cs
@@ -4,10 +4,7 @@
 // Created by: Denis Krjuchkov
 // Created:    2011.09.28
 
-using System;
-using System.Collections.Generic;
 using System.Diagnostics;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Sql.Drivers.SqlServer;
 
diff --git a/Orm/Xtensive.Orm.Tests.Sql/SqlServer/ExtractorTest.cs b/Orm/Xtensive.Orm.Tests.Sql/SqlServer/ExtractorTest.cs
index 2d6f4b6b3..fa87997b7 100644
--- a/Orm/Xtensive.Orm.Tests.Sql/SqlServer/ExtractorTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Sql/SqlServer/ExtractorTest.cs
@@ -6,10 +6,7 @@
 
 // TODO: Refactor stupid MSSqlExtractorTests.cs and put all stuff here
 
-using System;
-using System.Collections.Generic;
 using NUnit.Framework;
-using System.Linq;
 using Xtensive.Core;
 using Xtensive.Sql;
 using Xtensive.Sql.Model;
diff --git a/Orm/Xtensive.Orm.Tests.Sql/SqlServer/IndexTest.cs b/Orm/Xtensive.Orm.Tests.Sql/SqlServer/IndexTest.cs
index 072f2fe9f..3f4881ada 100644
--- a/Orm/Xtensive.Orm.Tests.Sql/SqlServer/IndexTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Sql/SqlServer/IndexTest.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2009.08.31
 
-using System;
 using NUnit.Framework;
 using Xtensive.Sql;
 using Xtensive.Sql.Dml;
diff --git a/Orm/Xtensive.Orm.Tests.Sql/SqlServer/MSSQLExtractorTests.cs b/Orm/Xtensive.Orm.Tests.Sql/SqlServer/MSSQLExtractorTests.cs
index b59d442e3..4b3a866a9 100644
--- a/Orm/Xtensive.Orm.Tests.Sql/SqlServer/MSSQLExtractorTests.cs
+++ b/Orm/Xtensive.Orm.Tests.Sql/SqlServer/MSSQLExtractorTests.cs
@@ -2,7 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
 using System.Text;
 using NUnit.Framework;
 using Xtensive.Sql;
diff --git a/Orm/Xtensive.Orm.Tests.Sql/SqlServer/MSSQLTests.cs b/Orm/Xtensive.Orm.Tests.Sql/SqlServer/MSSQLTests.cs
index 6952bdda8..bec893793 100644
--- a/Orm/Xtensive.Orm.Tests.Sql/SqlServer/MSSQLTests.cs
+++ b/Orm/Xtensive.Orm.Tests.Sql/SqlServer/MSSQLTests.cs
@@ -4,7 +4,6 @@
 
 using System.Diagnostics;
 using NUnit.Framework;
-using System;
 using System.Data;
 using System.Data.Common;
 using Xtensive.Sql;
@@ -13,9 +12,7 @@
 using Xtensive.Sql.Dml;
 using Xtensive.Sql.Model;
 using Index = Xtensive.Sql.Model.Index;
-using System.Linq;
 using Xtensive.Core;
-using System.Collections.Generic;
 
 namespace Xtensive.Orm.Tests.Sql.SqlServer
 {
diff --git a/Orm/Xtensive.Orm.Tests.Sql/SqlServer/MiscTests.cs b/Orm/Xtensive.Orm.Tests.Sql/SqlServer/MiscTests.cs
index 9b8faa660..86069f889 100644
--- a/Orm/Xtensive.Orm.Tests.Sql/SqlServer/MiscTests.cs
+++ b/Orm/Xtensive.Orm.Tests.Sql/SqlServer/MiscTests.cs
@@ -2,7 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
 using System.Data;
 using System.IO;
 using System.Runtime.Serialization.Formatters.Binary;
@@ -12,7 +11,6 @@
 using Xtensive.Sql.Compiler;
 using Xtensive.Sql.Dml;
 using System.Data.Common;
-using System.Linq;
 using Xtensive.Sql.Model;
 
 namespace Xtensive.Orm.Tests.Sql.SqlServer
diff --git a/Orm/Xtensive.Orm.Tests.Sql/SqlServer/SqlDecimalTest.cs b/Orm/Xtensive.Orm.Tests.Sql/SqlServer/SqlDecimalTest.cs
index 478f71d45..eb5c6c394 100644
--- a/Orm/Xtensive.Orm.Tests.Sql/SqlServer/SqlDecimalTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Sql/SqlServer/SqlDecimalTest.cs
@@ -4,13 +4,10 @@
 // Created by: Denis Kudelin
 // Created:    2019.03.19
 
-using System;
-using System.Collections.Generic;
 using Microsoft.Data.SqlClient;
 using System.Data.SqlTypes;
 using System.Diagnostics;
 using System.Globalization;
-using System.Linq;
 using System.Text;
 using NUnit.Framework;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm.Tests.Sql/SqlServerCe/ExtractorTest.cs b/Orm/Xtensive.Orm.Tests.Sql/SqlServerCe/ExtractorTest.cs
index 88c2b4f82..b6a2579e8 100644
--- a/Orm/Xtensive.Orm.Tests.Sql/SqlServerCe/ExtractorTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Sql/SqlServerCe/ExtractorTest.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.07.29
 
-using System;
 using NUnit.Framework;
 using Xtensive.Sql.Model;
 
diff --git a/Orm/Xtensive.Orm.Tests.Sql/SqlTest.cs b/Orm/Xtensive.Orm.Tests.Sql/SqlTest.cs
index dc1abfc38..737fedc24 100644
--- a/Orm/Xtensive.Orm.Tests.Sql/SqlTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Sql/SqlTest.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.07.21
 
-using System;
 using System.Data;
 using NUnit.Framework;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm.Tests.Sql/Sqlite/ChinookTest.cs b/Orm/Xtensive.Orm.Tests.Sql/Sqlite/ChinookTest.cs
index c61ebd20d..ccb19019e 100644
--- a/Orm/Xtensive.Orm.Tests.Sql/Sqlite/ChinookTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Sql/Sqlite/ChinookTest.cs
@@ -4,11 +4,9 @@
 // Created by: Malisa Ncube
 // Created:    2011.06.10
 
-using System;
 using System.Data;
 using System.Data.Common;
 using System.Diagnostics;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Sql;
diff --git a/Orm/Xtensive.Orm.Tests.Sql/Sqlite/ExtractorTest.cs b/Orm/Xtensive.Orm.Tests.Sql/Sqlite/ExtractorTest.cs
index 1e294c8bf..2e16021db 100644
--- a/Orm/Xtensive.Orm.Tests.Sql/Sqlite/ExtractorTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Sql/Sqlite/ExtractorTest.cs
@@ -4,7 +4,6 @@
 // Created by: Malisa Ncube
 // Created:    2011.03.16
 
-using System;
 using System.Text;
 using NUnit.Framework;
 using Xtensive.Sql;
diff --git a/Orm/Xtensive.Orm.Tests.Sql/Sqlite/MiscTests.cs b/Orm/Xtensive.Orm.Tests.Sql/Sqlite/MiscTests.cs
index 8e083188e..557a55952 100644
--- a/Orm/Xtensive.Orm.Tests.Sql/Sqlite/MiscTests.cs
+++ b/Orm/Xtensive.Orm.Tests.Sql/Sqlite/MiscTests.cs
@@ -4,7 +4,6 @@
 // Created by: Malisa Ncube
 // Created:    2011.05.13
 
-using System;
 using System.Data;
 using System.Data.Common;
 using System.Diagnostics;
diff --git a/Orm/Xtensive.Orm.Tests.Sql/Sqlite/TypeMappingTests.cs b/Orm/Xtensive.Orm.Tests.Sql/Sqlite/TypeMappingTests.cs
index 2a405d2db..7b5119c5d 100644
--- a/Orm/Xtensive.Orm.Tests.Sql/Sqlite/TypeMappingTests.cs
+++ b/Orm/Xtensive.Orm.Tests.Sql/Sqlite/TypeMappingTests.cs
@@ -4,9 +4,6 @@
 // Created by: Malisa Ncube
 // Created:    2011.05.13
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Text;
 using NUnit.Framework;
 using Xtensive.Orm.Tests.Sql;
diff --git a/Orm/Xtensive.Orm.Tests.Sql/TypeMappingTest.cs b/Orm/Xtensive.Orm.Tests.Sql/TypeMappingTest.cs
index da8044d59..54d833323 100644
--- a/Orm/Xtensive.Orm.Tests.Sql/TypeMappingTest.cs
+++ b/Orm/Xtensive.Orm.Tests.Sql/TypeMappingTest.cs
@@ -5,11 +5,8 @@
 // Created:    2009.07.08
 
 using NUnit.Framework;
-using System;
-using System.Collections.Generic;
 using System.Data;
 using System.Data.Common;
-using System.Linq;
 using Xtensive.Sql.Dml;
 using Xtensive.Sql;
 
diff --git a/Orm/Xtensive.Orm.Tests/Configuration/AppConfigTest.cs b/Orm/Xtensive.Orm.Tests/Configuration/AppConfigTest.cs
index 431ec5396..59d3fd639 100644
--- a/Orm/Xtensive.Orm.Tests/Configuration/AppConfigTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Configuration/AppConfigTest.cs
@@ -4,9 +4,7 @@
 // Created by: Alexey Gamzov
 // Created:    2008.08.06
 
-using System;
 using System.Configuration;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Linq;
 using Xtensive.Orm.Tests;
diff --git a/Orm/Xtensive.Orm.Tests/Configuration/MaxNumberOfConditionsTest.cs b/Orm/Xtensive.Orm.Tests/Configuration/MaxNumberOfConditionsTest.cs
index dfa095b2f..0d739691a 100644
--- a/Orm/Xtensive.Orm.Tests/Configuration/MaxNumberOfConditionsTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Configuration/MaxNumberOfConditionsTest.cs
@@ -2,7 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
 using NUnit.Framework;
 
 namespace Xtensive.Orm.Tests.Configuration
diff --git a/Orm/Xtensive.Orm.Tests/Configuration/SchemaTest.cs b/Orm/Xtensive.Orm.Tests/Configuration/SchemaTest.cs
index e102a6a01..4442c8716 100644
--- a/Orm/Xtensive.Orm.Tests/Configuration/SchemaTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Configuration/SchemaTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alena Mikshina
 // Created:    2013.10.04
 
-using System;
 using System.Diagnostics;
 using System.IO;
 using System.Xml;
diff --git a/Orm/Xtensive.Orm.Tests/Configuration/SessionInitializationTest.cs b/Orm/Xtensive.Orm.Tests/Configuration/SessionInitializationTest.cs
index 1286c9695..2bfc04718 100644
--- a/Orm/Xtensive.Orm.Tests/Configuration/SessionInitializationTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Configuration/SessionInitializationTest.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.03.13
 
-using System;
 using NUnit.Framework;
 using Xtensive.Caching;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm.Tests/Configuration/TypeRegistryTest.cs b/Orm/Xtensive.Orm.Tests/Configuration/TypeRegistryTest.cs
index ec2302915..66f668ec8 100644
--- a/Orm/Xtensive.Orm.Tests/Configuration/TypeRegistryTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Configuration/TypeRegistryTest.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2007.08.08
 
-using System;
 using System.Reflection;
 using NUnit.Framework;
 using Xtensive.Collections;
diff --git a/Orm/Xtensive.Orm.Tests/DomainConfigurationFactoryTest.cs b/Orm/Xtensive.Orm.Tests/DomainConfigurationFactoryTest.cs
index 8a27739fd..839495b03 100644
--- a/Orm/Xtensive.Orm.Tests/DomainConfigurationFactoryTest.cs
+++ b/Orm/Xtensive.Orm.Tests/DomainConfigurationFactoryTest.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2009.05.19
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Building.Builders;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Indexing/ForeignKeyInfoTest.cs b/Orm/Xtensive.Orm.Tests/Indexing/ForeignKeyInfoTest.cs
index 89b023b30..fff2e6d7b 100644
--- a/Orm/Xtensive.Orm.Tests/Indexing/ForeignKeyInfoTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Indexing/ForeignKeyInfoTest.cs
@@ -9,6 +9,7 @@
 using Xtensive.Orm.Upgrade.Model;
 using NUnit.Framework;
 using Xtensive.Orm.Tests;
+using AggregateException = Xtensive.Core.AggregateException;
 
 namespace Xtensive.Orm.Tests.Indexing
 {
diff --git a/Orm/Xtensive.Orm.Tests/Indexing/PrimaryIndexInfoTest.cs b/Orm/Xtensive.Orm.Tests/Indexing/PrimaryIndexInfoTest.cs
index 7e1901b96..f832f3da2 100644
--- a/Orm/Xtensive.Orm.Tests/Indexing/PrimaryIndexInfoTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Indexing/PrimaryIndexInfoTest.cs
@@ -4,9 +4,7 @@
 // Created by: Ivan Galkin
 // Created:    2009.03.17
 
-using System;
 using System.Diagnostics;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Orm.Tests;
diff --git a/Orm/Xtensive.Orm.Tests/Indexing/SecondaryIndexInfoTest.cs b/Orm/Xtensive.Orm.Tests/Indexing/SecondaryIndexInfoTest.cs
index adf2089c2..856cffe02 100644
--- a/Orm/Xtensive.Orm.Tests/Indexing/SecondaryIndexInfoTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Indexing/SecondaryIndexInfoTest.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.03.23
 
-using System;
 using System.Diagnostics;
 using NUnit.Framework;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm.Tests/Indexing/StorageActionTest.cs b/Orm/Xtensive.Orm.Tests/Indexing/StorageActionTest.cs
index ac5e57b83..25069081e 100644
--- a/Orm/Xtensive.Orm.Tests/Indexing/StorageActionTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Indexing/StorageActionTest.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.03.23
 
-using System;
 using System.Diagnostics;
 using NUnit.Framework;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm.Tests/Indexing/StorageInfoTest.cs b/Orm/Xtensive.Orm.Tests/Indexing/StorageInfoTest.cs
index 40c59b080..509d8bfc1 100644
--- a/Orm/Xtensive.Orm.Tests/Indexing/StorageInfoTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Indexing/StorageInfoTest.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.03.17
 
-using System;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Orm.Tests;
diff --git a/Orm/Xtensive.Orm.Tests/Interfaces/InterfaceImplementationTest.cs b/Orm/Xtensive.Orm.Tests/Interfaces/InterfaceImplementationTest.cs
index eea44d7db..bc57a31ea 100644
--- a/Orm/Xtensive.Orm.Tests/Interfaces/InterfaceImplementationTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Interfaces/InterfaceImplementationTest.cs
@@ -4,11 +4,9 @@
 // Created by: Alexis Kochetov
 // Created:    2010.05.18
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Interfaces.Model;
-using System.Linq;
 
 namespace Xtensive.Orm.Tests.Interfaces
 {
diff --git a/Orm/Xtensive.Orm.Tests/Interfaces/InterfaceTest.cs b/Orm/Xtensive.Orm.Tests/Interfaces/InterfaceTest.cs
index c72e00aa5..d8f931fdf 100644
--- a/Orm/Xtensive.Orm.Tests/Interfaces/InterfaceTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Interfaces/InterfaceTest.cs
@@ -4,8 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2009.09.08
 
-using System;
-using System.Linq;
 using System.Linq.Expressions;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Interfaces/KeyStructureConflictTest.cs b/Orm/Xtensive.Orm.Tests/Interfaces/KeyStructureConflictTest.cs
index 63a58e9f0..a21307902 100644
--- a/Orm/Xtensive.Orm.Tests/Interfaces/KeyStructureConflictTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Interfaces/KeyStructureConflictTest.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2009.09.10
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Interfaces.KeyStructureConflictTestModel;
diff --git a/Orm/Xtensive.Orm.Tests/Interfaces/TypeIdModeConflictTest.cs b/Orm/Xtensive.Orm.Tests/Interfaces/TypeIdModeConflictTest.cs
index 4e8d982e3..c5ed000b9 100644
--- a/Orm/Xtensive.Orm.Tests/Interfaces/TypeIdModeConflictTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Interfaces/TypeIdModeConflictTest.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2009.09.14
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Interfaces.TypeIdModeConflictTestModel;
diff --git a/Orm/Xtensive.Orm.Tests/Interfaces/UnusedTypeRemovalTest.cs b/Orm/Xtensive.Orm.Tests/Interfaces/UnusedTypeRemovalTest.cs
index f6546ecd6..4cc888bde 100644
--- a/Orm/Xtensive.Orm.Tests/Interfaces/UnusedTypeRemovalTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Interfaces/UnusedTypeRemovalTest.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2009.09.14
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Tests;
 using Xtensive.Orm;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/BatchingCommandProcessorFrenzy.cs b/Orm/Xtensive.Orm.Tests/Issues/BatchingCommandProcessorFrenzy.cs
index ecfe94099..c51e8a840 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/BatchingCommandProcessorFrenzy.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/BatchingCommandProcessorFrenzy.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.02.20
 
-using System.Collections.Generic;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.BatchingCommandProcessorFrenzyModel;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/CustomCompilerException.cs b/Orm/Xtensive.Orm.Tests/Issues/CustomCompilerException.cs
index c3f525ecc..58a52ff72 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/CustomCompilerException.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/CustomCompilerException.cs
@@ -4,14 +4,12 @@
 // Created by: Alexis Kochetov
 // Created:    2011.05.29
 
-using System;
 using System.Diagnostics;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Linq;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.ProjectCustomCompilerException.Model;
-using System.Linq;
 
 namespace Xtensive.Orm.Tests.Issues
 {
diff --git a/Orm/Xtensive.Orm.Tests/Issues/CustomCompilerFeatureTest.cs b/Orm/Xtensive.Orm.Tests/Issues/CustomCompilerFeatureTest.cs
index f32deb4f4..6920a7d1f 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/CustomCompilerFeatureTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/CustomCompilerFeatureTest.cs
@@ -4,8 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2011.05.29
 
-using System;
-using System.Linq;
 using System.Linq.Expressions;
 using NUnit.Framework;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/InterfaceEntitySetTest.cs b/Orm/Xtensive.Orm.Tests/Issues/InterfaceEntitySetTest.cs
index c000beaae..8b49149b1 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/InterfaceEntitySetTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/InterfaceEntitySetTest.cs
@@ -1,4 +1,3 @@
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0001_MultipleHierarchyRootAttributes.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0001_MultipleHierarchyRootAttributes.cs
index eece89cd1..bf49e49ef 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0001_MultipleHierarchyRootAttributes.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0001_MultipleHierarchyRootAttributes.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2008.10.16
 
-using System;
 using System.Reflection;
 using NUnit.Framework;
 using Xtensive.Orm.Tests;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0002_PrimaryKeyWithLazyLoad.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0002_PrimaryKeyWithLazyLoad.cs
index c1dae318c..d4eaa04a9 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0002_PrimaryKeyWithLazyLoad.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0002_PrimaryKeyWithLazyLoad.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2008.10.16
 
-using System;
 using System.Reflection;
 using NUnit.Framework;
 using Xtensive.Orm.Tests;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0003_NullablePrimaryKey.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0003_NullablePrimaryKey.cs
index 240358202..c90058fda 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0003_NullablePrimaryKey.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0003_NullablePrimaryKey.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2008.10.16
 
-using System;
 using System.Reflection;
 using NUnit.Framework;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0004_PairAttributeMisusageIsNotHandled.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0004_PairAttributeMisusageIsNotHandled.cs
index f9b4d21bc..edf4b2e07 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0004_PairAttributeMisusageIsNotHandled.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0004_PairAttributeMisusageIsNotHandled.cs
@@ -4,7 +4,6 @@
 // Created by: Elena Vakhtina
 // Created:    2008.11.26
 
-using System;
 using System.Reflection;
 using NUnit.Framework;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0007_InvalidNotNullConstraint.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0007_InvalidNotNullConstraint.cs
index 6fbcf822d..db9e4d008 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0007_InvalidNotNullConstraint.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0007_InvalidNotNullConstraint.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2008.11.25
 
-using System;
 using System.Reflection;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0009_2SymmetricTablesForMNRelationship.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0009_2SymmetricTablesForMNRelationship.cs
index 484d5683e..3ccfb70e4 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0009_2SymmetricTablesForMNRelationship.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0009_2SymmetricTablesForMNRelationship.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2008.11.26
 
-using System;
 using System.Reflection;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0012_TakeSkipSequence.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0012_TakeSkipSequence.cs
index 2d752bb19..c6d1b512d 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0012_TakeSkipSequence.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0012_TakeSkipSequence.cs
@@ -4,8 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2008.11.20
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Providers;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0013_SqlBuilderRequestTaskBug.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0013_SqlBuilderRequestTaskBug.cs
index 2c97e9ab7..af3d0f897 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0013_SqlBuilderRequestTaskBug.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0013_SqlBuilderRequestTaskBug.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2008.11.20
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.Issue0013_Model;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0014_SymmetricRelationshipIsUnsupported.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0014_SymmetricRelationshipIsUnsupported.cs
index 52b643b62..893333f74 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0014_SymmetricRelationshipIsUnsupported.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0014_SymmetricRelationshipIsUnsupported.cs
@@ -5,8 +5,6 @@
 // Created:    2008.11.26
 
 
-using System;
-using System.Linq;
 using System.Reflection;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0016_FieldOfInterfaceType.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0016_FieldOfInterfaceType.cs
index 577bf8864..4b1742e7e 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0016_FieldOfInterfaceType.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0016_FieldOfInterfaceType.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2008.12.09
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.Issue0016_Model;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0017_ReferentialActionCascade.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0017_ReferentialActionCascade.cs
index 47b47e9a3..0dd33d8d6 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0017_ReferentialActionCascade.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0017_ReferentialActionCascade.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2008.12.15
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.Issue0017_Model;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0021_InvalidSqlQuery.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0021_InvalidSqlQuery.cs
index a3f1c71df..688d6c900 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0021_InvalidSqlQuery.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0021_InvalidSqlQuery.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2009.01.19
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Model;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0028_1_1SymmetricAssociationBug.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0028_1_1SymmetricAssociationBug.cs
index de87d9122..df9740a53 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0028_1_1SymmetricAssociationBug.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0028_1_1SymmetricAssociationBug.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2009.02.12
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.Issue0028_1_1SymmetricAssociationBug_Model;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0036_AutomaticGenericTypesRegistration.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0036_AutomaticGenericTypesRegistration.cs
index 414a70ea5..829a9501b 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0036_AutomaticGenericTypesRegistration.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0036_AutomaticGenericTypesRegistration.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:  2009.05.13
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.Issue0036_Model;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0082_ReferentialManagerProblem.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0082_ReferentialManagerProblem.cs
index 2ecd259e5..12d0a49bc 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0082_ReferentialManagerProblem.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0082_ReferentialManagerProblem.cs
@@ -4,8 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2009.06.04
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.Issue0082_ReferentialManagerProblem_Model;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0096_NumerousSchemaExtraction.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0096_NumerousSchemaExtraction.cs
index 8d79fc0f3..64efb8cde 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0096_NumerousSchemaExtraction.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0096_NumerousSchemaExtraction.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.06.09
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Building.Definitions;
 using Xtensive.Orm.Model;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0167_SingleTableProblem.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0167_SingleTableProblem.cs
index 3a4b2da42..2b7dad4b0 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0167_SingleTableProblem.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0167_SingleTableProblem.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.06.09
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Model;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0188_ModelBuilderError.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0188_ModelBuilderError.cs
index 554af9382..b9428e1ea 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0188_ModelBuilderError.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0188_ModelBuilderError.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2009.06.12
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.Issue0188_ModelBuilderError_Model;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0245_StructureWhere.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0245_StructureWhere.cs
index 03a73f4e0..b9bc4421f 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0245_StructureWhere.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0245_StructureWhere.cs
@@ -4,8 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.06.25
 
-using System;
-using System.Linq;
 using System.Reflection;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0262_StructureAssignment.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0262_StructureAssignment.cs
index 8cd192f80..fb61045df 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0262_StructureAssignment.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0262_StructureAssignment.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2009.06.29
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.Issue0262_Model;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0271_EntityNotInserted.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0271_EntityNotInserted.cs
index a241b7f86..c255aa462 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0271_EntityNotInserted.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0271_EntityNotInserted.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2009.07.07
 
-using System;
 using System.Reflection;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0276_DuplicateIndex.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0276_DuplicateIndex.cs
index d8c0aaa72..50c61ef92 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0276_DuplicateIndex.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0276_DuplicateIndex.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2009.09.29
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Model;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0282_EntitySetContains.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0282_EntitySetContains.cs
index a565b7a2c..1a0b5f8f0 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0282_EntitySetContains.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0282_EntitySetContains.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2009.07.10
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.Issue0282_EntitySetContains_Model;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0296_DeferredConstraints.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0296_DeferredConstraints.cs
index 90a64a42c..0efdbdbc8 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0296_DeferredConstraints.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0296_DeferredConstraints.cs
@@ -4,8 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2009.07.21
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.Issue0296_Model;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0298_InheritedAssociationIsIgnored.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0298_InheritedAssociationIsIgnored.cs
index 0b14e3d87..76edfeab4 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0298_InheritedAssociationIsIgnored.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0298_InheritedAssociationIsIgnored.cs
@@ -4,13 +4,10 @@
 // Created by: a
 // Created:    a
 
-using System;
-using System.Collections.Generic;
 using NUnit.Framework;
 using Xtensive.Orm.Tests;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.Issue0298_Model;
-using System.Linq;
 
 namespace Xtensive.Orm.Tests.Issues.Issue0298_Model
 {
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0307_EntitySetOfType.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0307_EntitySetOfType.cs
index 6709e26d2..ead30cb0e 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0307_EntitySetOfType.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0307_EntitySetOfType.cs
@@ -4,8 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.08.13
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.Issue0307_EntitySetOfType_Model;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0331_ForgetHierarchyRoot.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0331_ForgetHierarchyRoot.cs
index 5afaa79f8..bc83ff347 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0331_ForgetHierarchyRoot.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0331_ForgetHierarchyRoot.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2009.08.03
 
-using System;
 using Xtensive.Orm.Tests;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.Issue0331_ForgetHierarchyRoot_Model;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0351_NameBuilderProblem.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0351_NameBuilderProblem.cs
index 2ec228c24..c804da328 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0351_NameBuilderProblem.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0351_NameBuilderProblem.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2009.08.24
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.Issue0351_NameBuilderProblem_Model;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0359_UpgradeUsingAutoshortenTransaction.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0359_UpgradeUsingAutoshortenTransaction.cs
index 62aa8ec32..182b9c43f 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0359_UpgradeUsingAutoshortenTransaction.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0359_UpgradeUsingAutoshortenTransaction.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2009.08.24
 
-using System;
 using System.Transactions;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.Issue0359_CustomSessionConfigurationProblem_Model;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0370_EntitiSetIsNotHandledProperly.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0370_EntitiSetIsNotHandledProperly.cs
index 8619b2fba..6e3806808 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0370_EntitiSetIsNotHandledProperly.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0370_EntitiSetIsNotHandledProperly.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2009.09.03
 
-using System;
 using System.Runtime.Serialization;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0371_ObjectEquals.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0371_ObjectEquals.cs
index 00d6def6b..c341869a1 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0371_ObjectEquals.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0371_ObjectEquals.cs
@@ -4,12 +4,10 @@
 // Created by: Alexey Gamzov
 // Created:    2009.09.02
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Linq;
 using Xtensive.Orm.Tests.Issues.Issue0371_ObjectEquals_Model;
-using System.Linq;
 using Xtensive.Orm.Tests.Linq;
 
 namespace Xtensive.Orm.Tests.Issues.Issue0371_ObjectEquals_Model
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0372_SelfReferenceWithInheritance.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0372_SelfReferenceWithInheritance.cs
index 2e1f1f93d..28e313b5b 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0372_SelfReferenceWithInheritance.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0372_SelfReferenceWithInheritance.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2009.09.03
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.Issue0372_SelfReferenceWithInheritance_Model;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0376_RemoveFieldHint.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0376_RemoveFieldHint.cs
index 35e80c6b2..d65edcced 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0376_RemoveFieldHint.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0376_RemoveFieldHint.cs
@@ -4,15 +4,12 @@
 // Created by: Ivan Galkin
 // Created:    2009.10.09
 
-using System;
-using System.Collections.Generic;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Providers;
 using Xtensive.Orm.Upgrade;
 using System.Reflection;
-using System.Linq;
 
 #region Models
 
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0391_OnRemoveActionNone.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0391_OnRemoveActionNone.cs
index fce25228e..066face8b 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0391_OnRemoveActionNone.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0391_OnRemoveActionNone.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2009.09.21
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.Issue0391_OnRemoveActionNone_Model;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0394_UndefinedSqlTypeExtractionError.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0394_UndefinedSqlTypeExtractionError.cs
index 3fbb2a991..160b71a9e 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0394_UndefinedSqlTypeExtractionError.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0394_UndefinedSqlTypeExtractionError.cs
@@ -8,7 +8,6 @@
 using Xtensive.Core;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Providers;
-using System.Linq;
 using Xtensive.Orm.Tests.ObjectModel.ChinookDO;
 using Xtensive.Sql;
 
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0402_WrongEntitySetQuery.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0402_WrongEntitySetQuery.cs
index de46c1381..a466f60c1 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0402_WrongEntitySetQuery.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0402_WrongEntitySetQuery.cs
@@ -4,8 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2009.09.15
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.Issue0402_WrongEntitySetQuery_Model;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0408_EntitySetNullReference.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0408_EntitySetNullReference.cs
index 959e099f8..174cb6915 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0408_EntitySetNullReference.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0408_EntitySetNullReference.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Gamzov
 // Created:    2009.09.17
 
-using System;
-using System.Collections.Generic;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.Issue0408_EntitySetNullReference_Model;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0408_EntitySetNullReference_Model/Container.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0408_EntitySetNullReference_Model/Container.cs
index 793840574..3e4940df6 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0408_EntitySetNullReference_Model/Container.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0408_EntitySetNullReference_Model/Container.cs
@@ -1,4 +1,3 @@
-using System;
 
 namespace Xtensive.Orm.Tests.Issues.Issue0408_EntitySetNullReference_Model
 {
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0408_EntitySetNullReference_Model/CreateObjects.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0408_EntitySetNullReference_Model/CreateObjects.cs
index 0d93ddb2d..d492d616d 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0408_EntitySetNullReference_Model/CreateObjects.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0408_EntitySetNullReference_Model/CreateObjects.cs
@@ -1,6 +1,3 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Text;
 using Xtensive.Orm;
 
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0408_EntitySetNullReference_Model/Document.History.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0408_EntitySetNullReference_Model/Document.History.cs
index 3d622edbb..f9229dfc5 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0408_EntitySetNullReference_Model/Document.History.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0408_EntitySetNullReference_Model/Document.History.cs
@@ -1,6 +1,3 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Text;
 using Xtensive.Orm;
 
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0408_EntitySetNullReference_Model/Document.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0408_EntitySetNullReference_Model/Document.cs
index 561f141f3..65bc831eb 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0408_EntitySetNullReference_Model/Document.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0408_EntitySetNullReference_Model/Document.cs
@@ -1,6 +1,3 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Text;
 using Xtensive.Orm;
 
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0408_EntitySetNullReference_Model/DocumentLink.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0408_EntitySetNullReference_Model/DocumentLink.cs
index b1f933890..9781b2ed3 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0408_EntitySetNullReference_Model/DocumentLink.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0408_EntitySetNullReference_Model/DocumentLink.cs
@@ -1,4 +1,3 @@
-using System;
 
 namespace Xtensive.Orm.Tests.Issues.Issue0408_EntitySetNullReference_Model
 {
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0408_EntitySetNullReference_Model/EchoProcessor.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0408_EntitySetNullReference_Model/EchoProcessor.cs
index d2d441a9b..00442e02e 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0408_EntitySetNullReference_Model/EchoProcessor.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0408_EntitySetNullReference_Model/EchoProcessor.cs
@@ -1,6 +1,3 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Text;
 
 namespace Xtensive.Orm.Tests.Issues.Issue0408_EntitySetNullReference_Model
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0408_EntitySetNullReference_Model/ErrorDocument.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0408_EntitySetNullReference_Model/ErrorDocument.cs
index d2ec738c1..0ad9876d0 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0408_EntitySetNullReference_Model/ErrorDocument.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0408_EntitySetNullReference_Model/ErrorDocument.cs
@@ -1,4 +1,3 @@
-using System;
 
 namespace Xtensive.Orm.Tests.Issues.Issue0408_EntitySetNullReference_Model
 {
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0408_EntitySetNullReference_Model/HistoryEntry.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0408_EntitySetNullReference_Model/HistoryEntry.cs
index c96b7bee5..c0c1c444f 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0408_EntitySetNullReference_Model/HistoryEntry.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0408_EntitySetNullReference_Model/HistoryEntry.cs
@@ -1,4 +1,3 @@
-using System;
 
 namespace Xtensive.Orm.Tests.Issues.Issue0408_EntitySetNullReference_Model
 {
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0408_EntitySetNullReference_Model/HistoryEntryVisibility.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0408_EntitySetNullReference_Model/HistoryEntryVisibility.cs
index cfa3c5950..90f01bd90 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0408_EntitySetNullReference_Model/HistoryEntryVisibility.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0408_EntitySetNullReference_Model/HistoryEntryVisibility.cs
@@ -1,6 +1,3 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Text;
 
 namespace Xtensive.Orm.Tests.Issues.Issue0408_EntitySetNullReference_Model
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0408_EntitySetNullReference_Model/Processor.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0408_EntitySetNullReference_Model/Processor.cs
index de07652cc..0a2c7e2d5 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0408_EntitySetNullReference_Model/Processor.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0408_EntitySetNullReference_Model/Processor.cs
@@ -1,5 +1,3 @@
-using System;
-using System.Linq;
 
 namespace Xtensive.Orm.Tests.Issues.Issue0408_EntitySetNullReference_Model
 {
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0408_EntitySetNullReference_Model/QueueProcessor.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0408_EntitySetNullReference_Model/QueueProcessor.cs
index 0d575a158..50df1d652 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0408_EntitySetNullReference_Model/QueueProcessor.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0408_EntitySetNullReference_Model/QueueProcessor.cs
@@ -1,6 +1,3 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Text;
 using Xtensive.Orm;
 using System.Diagnostics;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0409_ConstructorTransactional.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0409_ConstructorTransactional.cs
index 93a40654f..0a7e7bca7 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0409_ConstructorTransactional.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0409_ConstructorTransactional.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Gamzov
 // Created:    2009.09.17
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.Issue0409_ConstructorTransactional_Model;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0422_GetStructureFieldsForComplexStructures.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0422_GetStructureFieldsForComplexStructures.cs
index 9590eb0c8..28c4224bb 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0422_GetStructureFieldsForComplexStructures.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0422_GetStructureFieldsForComplexStructures.cs
@@ -4,9 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2009.10.05
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Providers;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0424_SqlCommandIsNull.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0424_SqlCommandIsNull.cs
index 84997aecb..f0eb3e987 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0424_SqlCommandIsNull.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0424_SqlCommandIsNull.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.10.08
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.Issue0296_Model;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0435_BatchingFail.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0435_BatchingFail.cs
index f6a608511..0fd3303f9 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0435_BatchingFail.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0435_BatchingFail.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.10.15
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.Issue0435_Model;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0452_OrderByIncorrectColumn.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0452_OrderByIncorrectColumn.cs
index e2937ce56..1cd84b4a1 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0452_OrderByIncorrectColumn.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0452_OrderByIncorrectColumn.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2009.10.26
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Providers;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0457_EntityStateToString.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0457_EntityStateToString.cs
index e3cde5bfa..9779f4b0b 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0457_EntityStateToString.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0457_EntityStateToString.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Kofman
 // Created:    2009.10.29
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.Issue0457_EntityStateToStringModel;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0485_EntitySetDescendant.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0485_EntitySetDescendant.cs
index c6e50a3cf..b2509fa9e 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0485_EntitySetDescendant.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0485_EntitySetDescendant.cs
@@ -4,14 +4,12 @@
 // Created by: Alexey Gamzov
 // Created:    2009.11.26
 
-using System;
 using System.Runtime.Serialization;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Model;
 using Xtensive.Orm.Providers;
 using Xtensive.Orm.Tests.Issues.Issue0485_EntitySetDescendant_Model;
-using System.Linq;
 
 namespace Xtensive.Orm.Tests.Issues.Issue0485_EntitySetDescendant_Model
 {
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0490_GroupByWithTypeId.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0490_GroupByWithTypeId.cs
index 43d100f3c..21518babe 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0490_GroupByWithTypeId.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0490_GroupByWithTypeId.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2009.12.03
 
-using System.Linq;
 using System.Linq.Expressions;
 using NUnit.Framework;
 using Xtensive.Linq;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0493_BadImageFormatTest.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0493_BadImageFormatTest.cs
index c9023b0e8..f4ecc88a8 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0493_BadImageFormatTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0493_BadImageFormatTest.cs
@@ -1,5 +1,3 @@
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.Issue0493_BadImageFormatTest_Model;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0512_NullableGetValueOrDefaultIsNotSupported.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0512_NullableGetValueOrDefaultIsNotSupported.cs
index e7d26f3cb..bae17bdd4 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0512_NullableGetValueOrDefaultIsNotSupported.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0512_NullableGetValueOrDefaultIsNotSupported.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.12.06
 
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Storage.DbTypeSupportModel;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0559_EntitySetQueryError.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0559_EntitySetQueryError.cs
index 41acd66fa..bbfd95034 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0559_EntitySetQueryError.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0559_EntitySetQueryError.cs
@@ -4,8 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.12.23
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.Issue0559_EntitySetQueryError_Model;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0585_TakeSkipJoinMappingError.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0585_TakeSkipJoinMappingError.cs
index 53052e297..431c32ba4 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0585_TakeSkipJoinMappingError.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0585_TakeSkipJoinMappingError.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2010.01.19
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Providers;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0587_ByteArrayEquals.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0587_ByteArrayEquals.cs
index affb47984..7dea8ce20 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0587_ByteArrayEquals.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0587_ByteArrayEquals.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2010.01.22
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.Issue0587_ByteArrayEquals_Model;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0593_OverrideDefaultSchema.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0593_OverrideDefaultSchema.cs
index 22a7c1be0..659c03771 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0593_OverrideDefaultSchema.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0593_OverrideDefaultSchema.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2010.02.02
 
-using System;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Sql;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0597_OpenGenericsInDomainModel.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0597_OpenGenericsInDomainModel.cs
index cf8d025c9..91a5529f1 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0597_OpenGenericsInDomainModel.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0597_OpenGenericsInDomainModel.cs
@@ -4,9 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2010.02.08
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.Issue0597_OpenGenericsInDomainModel_Model;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0624_EntitySetSubqueryError.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0624_EntitySetSubqueryError.cs
index ab189164c..7e5a11b1f 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0624_EntitySetSubqueryError.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0624_EntitySetSubqueryError.cs
@@ -4,9 +4,7 @@
 // Created by: Alexis Kochetov
 // Created:    2010.03.24
 
-using System;
 using System.Diagnostics;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0626_SequenceContainsNoElements.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0626_SequenceContainsNoElements.cs
index 8b723b4ae..40c8950e4 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0626_SequenceContainsNoElements.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0626_SequenceContainsNoElements.cs
@@ -4,9 +4,7 @@
 // Created by: Alexis Kochetov
 // Created:    2010.03.24
 
-using System;
 using System.Diagnostics;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Providers;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0628_ExecuteFutureScalarError.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0628_ExecuteFutureScalarError.cs
index c44076102..5d49ece81 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0628_ExecuteFutureScalarError.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0628_ExecuteFutureScalarError.cs
@@ -4,10 +4,8 @@
 // Created by: Alexis Kochetov
 // Created:    2010.03.24
 
-using System;
 using System.Collections;
 using System.Diagnostics;
-using System.Linq;
 using System.Linq.Dynamic;
 using System.Reflection;
 using NUnit.Framework;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0630_NullReferenceOnSelect.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0630_NullReferenceOnSelect.cs
index e6228df27..2f47f133c 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0630_NullReferenceOnSelect.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0630_NullReferenceOnSelect.cs
@@ -4,9 +4,7 @@
 // Created by: Alexis Kochetov
 // Created:    2010.03.24
 
-using System;
 using System.Collections;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.Issue0630_NullReferenceOnSelect_Model;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0634_PairToMisuse.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0634_PairToMisuse.cs
index 101402e3d..ba4347749 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0634_PairToMisuse.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0634_PairToMisuse.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2010.06.07
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Tests;
 using Xtensive.Orm.Tests.Issues.Issue0634_PairToMisuse_Model;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0641_GroupBySumError.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0641_GroupBySumError.cs
index 634656e92..b64c52d7e 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0641_GroupBySumError.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0641_GroupBySumError.cs
@@ -4,8 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2010.03.24
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.Issue0641_GroupBySumError_Model;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0643_EntitySetAddInCtor.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0643_EntitySetAddInCtor.cs
index 3eb4786c7..d94d973cd 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0643_EntitySetAddInCtor.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0643_EntitySetAddInCtor.cs
@@ -4,8 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2010.03.24
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.Issue0643_EntitySetAddInCtor_Model;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0647_WrongLinqQuery.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0647_WrongLinqQuery.cs
index 25242d2c6..b23a547e4 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0647_WrongLinqQuery.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0647_WrongLinqQuery.cs
@@ -4,8 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2010.03.24
 
-using System;
-using System.Linq;
 using System.Linq.Expressions;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0648_MultiThreadNullReference.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0648_MultiThreadNullReference.cs
index 7be23e85b..4397c3e8f 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0648_MultiThreadNullReference.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0648_MultiThreadNullReference.cs
@@ -4,9 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2010.03.24
 
-using System;
-using System.Linq;
-using System.Threading;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.Issue0648_MultiThreadNullReference_Model;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0676_NonNullableReferenceBug.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0676_NonNullableReferenceBug.cs
index f947ff766..fb4bf485e 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0676_NonNullableReferenceBug.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0676_NonNullableReferenceBug.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2010.06.24
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Tests;
 using Xtensive.Orm;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0682_FieldInfoIsNullable.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0682_FieldInfoIsNullable.cs
index 6593238a7..24a14000f 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0682_FieldInfoIsNullable.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0682_FieldInfoIsNullable.cs
@@ -4,8 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2009.01.19
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0689_WeirdExceptionWhenMissingConnectionInfo.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0689_WeirdExceptionWhenMissingConnectionInfo.cs
index e29c63d1e..b1f846573 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0689_WeirdExceptionWhenMissingConnectionInfo.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0689_WeirdExceptionWhenMissingConnectionInfo.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2010.06.08
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Tests;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0690_RemoveAndCreate.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0690_RemoveAndCreate.cs
index 74b2b6943..ac86b121a 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0690_RemoveAndCreate.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0690_RemoveAndCreate.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2010.06.11
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issue0690_Model;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0696_EntitySetItemAddBug.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0696_EntitySetItemAddBug.cs
index a6b23ad3c..f49598fd8 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0696_EntitySetItemAddBug.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0696_EntitySetItemAddBug.cs
@@ -4,9 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2010.06.24
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Orm;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0713_InconsistentDefaultDateTimeValues.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0713_InconsistentDefaultDateTimeValues.cs
index aeb999863..50cad7375 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0713_InconsistentDefaultDateTimeValues.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0713_InconsistentDefaultDateTimeValues.cs
@@ -4,9 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2010.06.21
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Upgrade;
 
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0715_NestedTypeBug.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0715_NestedTypeBug.cs
index 85b20e79f..36b0d397f 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0715_NestedTypeBug.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0715_NestedTypeBug.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2010.06.24
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0717_VersionCheckBug.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0717_VersionCheckBug.cs
index 9725fe9e0..e2131c89d 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0717_VersionCheckBug.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0717_VersionCheckBug.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2010.06.24
 
-using System;
-using System.Collections.Generic;
 using System.Transactions;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0733_UseINNER_JOIN.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0733_UseINNER_JOIN.cs
index 1329ee61b..b3216c23f 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0733_UseINNER_JOIN.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0733_UseINNER_JOIN.cs
@@ -4,12 +4,10 @@
 // Created by: Alexis Kochetov
 // Created:    2010.07.12
 
-using System;
 using System.Diagnostics;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.Issue0737_PersistentFieldState_Model;
-using System.Linq;
 
 namespace Xtensive.Orm.Tests.Issues
 {
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0737_PersistentFieldState.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0737_PersistentFieldState.cs
index 9ba88d542..4c88d8914 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0737_PersistentFieldState.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0737_PersistentFieldState.cs
@@ -4,12 +4,10 @@
 // Created by: Alexis Kochetov
 // Created:    2010.07.12
 
-using System;
 using System.Diagnostics;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.Issue0733_UseINNER_JOIN_Model;
-using System.Linq;
 
 namespace Xtensive.Orm.Tests.Issues
 {
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0751_EntitySetEquals.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0751_EntitySetEquals.cs
index 1606457fc..c1c508e7a 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0751_EntitySetEquals.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0751_EntitySetEquals.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2010.08.31
 
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0754_CopyFieldHint_MoveFieldHint/Issue0754_CopyFieldHint_MoveFieldHint.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0754_CopyFieldHint_MoveFieldHint/Issue0754_CopyFieldHint_MoveFieldHint.cs
index e35de1f92..bb8d0c0f0 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0754_CopyFieldHint_MoveFieldHint/Issue0754_CopyFieldHint_MoveFieldHint.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0754_CopyFieldHint_MoveFieldHint/Issue0754_CopyFieldHint_MoveFieldHint.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Gamzov
 // Created:    2010.11.17
 
-using System;
-using System.Linq;
 using System.Reflection;
 using NUnit.Framework;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0754_CopyFieldHint_MoveFieldHint/ModelVersion1.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0754_CopyFieldHint_MoveFieldHint/ModelVersion1.cs
index 3b8d50b89..eef6e02c1 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0754_CopyFieldHint_MoveFieldHint/ModelVersion1.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0754_CopyFieldHint_MoveFieldHint/ModelVersion1.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Gamzov
 // Created:    2010.11.17
 
-using System;
 
 namespace Xtensive.Orm.Tests.Issues.Issue0754_CopyFieldHint_MoveFieldHint.ModelVersion1
 {
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0754_CopyFieldHint_MoveFieldHint/ModelVersion2.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0754_CopyFieldHint_MoveFieldHint/ModelVersion2.cs
index 28b4c4111..9935bc246 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0754_CopyFieldHint_MoveFieldHint/ModelVersion2.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0754_CopyFieldHint_MoveFieldHint/ModelVersion2.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Gamzov
 // Created:    2010.11.17
 
-using System;
 
 namespace Xtensive.Orm.Tests.Issues.Issue0754_CopyFieldHint_MoveFieldHint.ModelVersion2
 {
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0754_CopyFieldHint_MoveFieldHint/Upgrader.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0754_CopyFieldHint_MoveFieldHint/Upgrader.cs
index 423830c27..38719c850 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0754_CopyFieldHint_MoveFieldHint/Upgrader.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0754_CopyFieldHint_MoveFieldHint/Upgrader.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Gamzov
 // Created:    2010.11.17
 
-using System.Collections.Generic;
 using Xtensive.Orm.Upgrade;
 
 namespace Xtensive.Orm.Tests.Issues.Issue0754_CopyFieldHint_MoveFieldHint
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0764_LinqTranslationError.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0764_LinqTranslationError.cs
index 0c6037b2f..a46d7dce0 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0764_LinqTranslationError.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0764_LinqTranslationError.cs
@@ -4,12 +4,10 @@
 // Created by: Alexis Kochetov
 // Created:    2010.07.12
 
-using System;
 using System.Diagnostics;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.Issue0764_LinqTranslationError_Model;
-using System.Linq;
 
 namespace Xtensive.Orm.Tests.Issues
 {
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0765_LinqTranslationError.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0765_LinqTranslationError.cs
index 50a648679..36b33ffce 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0765_LinqTranslationError.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0765_LinqTranslationError.cs
@@ -4,12 +4,10 @@
 // Created by: Alexis Kochetov
 // Created:    2010.07.23
 
-using System;
 using System.Diagnostics;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.Issue0765_LinqTranslationError_Model;
-using System.Linq;
 
 namespace Xtensive.Orm.Tests.Issues
 {
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0766_LinqTranslationError.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0766_LinqTranslationError.cs
index 4cdf0ad98..aaed3e02b 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0766_LinqTranslationError.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0766_LinqTranslationError.cs
@@ -4,10 +4,8 @@
 // Created by: Alexis Kochetov
 // Created:    2010.07.23
 
-using System;
 using System.Diagnostics;
 using NUnit.Framework;
-using System.Linq;
 using Xtensive.Orm.Providers;
 using Xtensive.Orm.Tests.ObjectModel;
 using Xtensive.Orm.Tests.ObjectModel.ChinookDO;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0767_QueryByInterfaceException.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0767_QueryByInterfaceException.cs
index c3eb46519..ad25448c1 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0767_QueryByInterfaceException.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0767_QueryByInterfaceException.cs
@@ -4,10 +4,8 @@
 // Created by: Alexis Kochetov
 // Created:    2010.07.26
 
-using System;
 using System.Diagnostics;
 using NUnit.Framework;
-using System.Linq;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Model;
 using Xtensive.Orm.Tests.Issues.Issue0767_QueryByInterfaceException_Model;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0768_WrongJoinBehavior.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0768_WrongJoinBehavior.cs
index 4415c9f4a..bf307d777 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0768_WrongJoinBehavior.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0768_WrongJoinBehavior.cs
@@ -4,11 +4,9 @@
 // Created by: Alexis Kochetov
 // Created:    2010.07.26
 
-using System;
 using System.Diagnostics;
 using System.Linq.Expressions;
 using NUnit.Framework;
-using System.Linq;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Model;
 using Xtensive.Orm.Tests.Issues.Issue0768_WrongJoinBehavior_Model;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0771_AbstractTypeRegistration.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0771_AbstractTypeRegistration.cs
index 5daddc630..7e2a578a5 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0771_AbstractTypeRegistration.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0771_AbstractTypeRegistration.cs
@@ -4,11 +4,9 @@
 // Created by: Alexis Kochetov
 // Created:    2010.07.26
 
-using System;
 using System.Diagnostics;
 using System.Linq.Expressions;
 using NUnit.Framework;
-using System.Linq;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Model;
 using Xtensive.Orm.Tests.Issues.Issue0771_AbstractTypeRegistration_Model;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0773_UnableTranslateUnionQuery.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0773_UnableTranslateUnionQuery.cs
index 61b7800f9..8aa54d26a 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0773_UnableTranslateUnionQuery.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0773_UnableTranslateUnionQuery.cs
@@ -4,9 +4,7 @@
 // Created by: Alexis Kochetov
 // Created:    2010.08.11
 
-using System;
 using System.Diagnostics;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Tests.ObjectModel;
 using Xtensive.Orm.Tests.ObjectModel.ChinookDO;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0775_WrongLinqQueryOverComputedFields.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0775_WrongLinqQueryOverComputedFields.cs
index 39ae5e5e8..6bd872ed4 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0775_WrongLinqQueryOverComputedFields.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0775_WrongLinqQueryOverComputedFields.cs
@@ -4,8 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2010.08.13
 
-using System;
-using System.Linq;
 using System.Linq.Expressions;
 using NUnit.Framework;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0776_OrderingCorrectorOfAggregateProvider.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0776_OrderingCorrectorOfAggregateProvider.cs
index 71ccacafc..c3ddf3a5e 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0776_OrderingCorrectorOfAggregateProvider.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0776_OrderingCorrectorOfAggregateProvider.cs
@@ -4,8 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2010.08.13
 
-using System;
-using System.Linq;
 using System.Linq.Expressions;
 using NUnit.Framework;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0777_WrongLinqQueryConditional.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0777_WrongLinqQueryConditional.cs
index e79d28c3b..fdd950764 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0777_WrongLinqQueryConditional.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0777_WrongLinqQueryConditional.cs
@@ -4,12 +4,10 @@
 // Created by: Alexis Kochetov
 // Created:    2010.08.13
 
-using System;
 using System.Diagnostics;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.Issue0777_WrongLinqQueryConditional_Model;
-using System.Linq;
 
 namespace Xtensive.Orm.Tests.Issues
 {
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0785_GenericStructureBugs.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0785_GenericStructureBugs.cs
index 3edfa8be3..e9053dc5e 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0785_GenericStructureBugs.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0785_GenericStructureBugs.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2010.06.24
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0788_EntityIsDetached.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0788_EntityIsDetached.cs
index 8e3c492dc..562680b6d 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0788_EntityIsDetached.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0788_EntityIsDetached.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2010.08.27
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.Issue0788_EntityIsDetached_Model;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0792_OrderByWithDistinct.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0792_OrderByWithDistinct.cs
index a0248667e..ed60217d3 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0792_OrderByWithDistinct.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0792_OrderByWithDistinct.cs
@@ -1,4 +1,3 @@
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0800_OrderByEnum.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0800_OrderByEnum.cs
index 1f5106e55..4f2c201f4 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0800_OrderByEnum.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0800_OrderByEnum.cs
@@ -1,6 +1,3 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Text;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0806_ColumnNamingError.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0806_ColumnNamingError.cs
index 00638b1ab..6b1e977f7 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0806_ColumnNamingError.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0806_ColumnNamingError.cs
@@ -1,6 +1,3 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Text;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0808_StructSerialization.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0808_StructSerialization.cs
index 3135b9554..bb1f89433 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0808_StructSerialization.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0808_StructSerialization.cs
@@ -1,7 +1,4 @@
-using System;
-using System.Collections.Generic;
 using System.IO;
-using System.Linq;
 using System.Linq.Expressions;
 using System.Runtime.Serialization;
 using NUnit.Framework;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0813_AuxilaryTableMappingNameBug.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0813_AuxilaryTableMappingNameBug.cs
index 7bd5c42bc..de3690f89 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0813_AuxilaryTableMappingNameBug.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0813_AuxilaryTableMappingNameBug.cs
@@ -4,8 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2010.10.27
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.Issue0813_AuxilaryTableMappingNameBug_Model;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0817_LocalCollectionWithEnum.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0817_LocalCollectionWithEnum.cs
index b949fc67a..50651522f 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0817_LocalCollectionWithEnum.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0817_LocalCollectionWithEnum.cs
@@ -1,4 +1,3 @@
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues_Issue0817_LocalCollectionWithEnum;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0818_NanosecondTrancation.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0818_NanosecondTrancation.cs
index bd68a0ca5..0eb37f923 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0818_NanosecondTrancation.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0818_NanosecondTrancation.cs
@@ -4,8 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2010.10.14
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.Issue0818_NanosecondTrancation_Model;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0820_GroupByWithDatePart.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0820_GroupByWithDatePart.cs
index 66beecebb..1ecd592eb 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0820_GroupByWithDatePart.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0820_GroupByWithDatePart.cs
@@ -1,5 +1,3 @@
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues_Issue0820_GroupByWithDatePart;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0821_StructureNulComparisonInLinq.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0821_StructureNulComparisonInLinq.cs
index 69639b3ff..b25ab9c47 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0821_StructureNulComparisonInLinq.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0821_StructureNulComparisonInLinq.cs
@@ -1,6 +1,3 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Text;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0825_StrangeLinqBehavior.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0825_StrangeLinqBehavior.cs
index 283aa5ede..59a24b388 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0825_StrangeLinqBehavior.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0825_StrangeLinqBehavior.cs
@@ -4,9 +4,7 @@
 // Created by: Alexey Gamzov
 // Created:    2010.10.07
 
-using System;
 using System.Diagnostics;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Providers;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0826_OperandTypeClash.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0826_OperandTypeClash.cs
index 6c9786a1a..afd21b83c 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0826_OperandTypeClash.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0826_OperandTypeClash.cs
@@ -1,5 +1,3 @@
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Model;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0827_LinqDtoMaterialization.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0827_LinqDtoMaterialization.cs
index 3a7f5ceac..20667329e 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0827_LinqDtoMaterialization.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0827_LinqDtoMaterialization.cs
@@ -4,10 +4,7 @@
 // Created by: Alexey Gamzov
 // Created:    2010.10.08
 
-using System;
-using System.Collections.Generic;
 using System.Diagnostics;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues_Issue0827_LinqDtoMaterialization;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0828_LinqMaterializeException.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0828_LinqMaterializeException.cs
index 7a12a1fe2..2ffd25edf 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0828_LinqMaterializeException.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0828_LinqMaterializeException.cs
@@ -4,9 +4,7 @@
 // Created by: Alexey Gamzov
 // Created:    2010.10.11
 
-using System;
 using System.Diagnostics;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Providers;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0835_QueryNestedTooDeep.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0835_QueryNestedTooDeep.cs
index 0f6cd8c64..8f1059bc1 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0835_QueryNestedTooDeep.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0835_QueryNestedTooDeep.cs
@@ -1,5 +1,3 @@
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues_Issue0835_QueryNestedTooDeep;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0839_MultithreadingBug.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0839_MultithreadingBug.cs
index 72b836ec2..56682effe 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0839_MultithreadingBug.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0839_MultithreadingBug.cs
@@ -4,10 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2010.10.14
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Threading;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.Issue0839_MultithreadingBug_Model;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0844_GroupByConstant.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0844_GroupByConstant.cs
index ef0776b1b..408d0bf1e 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0844_GroupByConstant.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0844_GroupByConstant.cs
@@ -1,6 +1,3 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Text;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0845_KeyTypeAccessBug.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0845_KeyTypeAccessBug.cs
index 3ff2837a8..18d1e8836 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0845_KeyTypeAccessBug.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0845_KeyTypeAccessBug.cs
@@ -4,8 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2010.10.27
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Tests;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0847_IsOperator.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0847_IsOperator.cs
index 5efcbc625..58f63e650 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0847_IsOperator.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0847_IsOperator.cs
@@ -1,4 +1,3 @@
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues_Issue0847_IsOperator;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0851_AnyMappingError.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0851_AnyMappingError.cs
index 64f8c8a64..2b7911dae 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0851_AnyMappingError.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0851_AnyMappingError.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Gamzov
 // Created:    2010.10.22
 
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.Issue0851_AnyMappingError_Model;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue0860_DateTimeDate.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue0860_DateTimeDate.cs
index 9fa9b6ef4..a2f35c540 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue0860_DateTimeDate.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue0860_DateTimeDate.cs
@@ -1,11 +1,9 @@
-using System;
 using System.Diagnostics;
 using NUnit.Framework;
 using Xtensive.Orm.Tests;
 using Xtensive.Orm.Tests.Issues.Issue0860_DateTimeDateModel;
 using Xtensive.Orm;
 using Xtensive.Orm.Configuration;
-using System.Linq;
 
 namespace Xtensive.Orm.Tests.Issues
 {
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue679,681_EntitySetRelatedBugs.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue679,681_EntitySetRelatedBugs.cs
index 715c0f832..3fe5bdb62 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue679,681_EntitySetRelatedBugs.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue679,681_EntitySetRelatedBugs.cs
@@ -4,8 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2009.01.19
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueA363_WrongInnerJoin.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueA363_WrongInnerJoin.cs
index 3f9e70456..560987073 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueA363_WrongInnerJoin.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueA363_WrongInnerJoin.cs
@@ -4,8 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2011.01.21
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.IssueA363_WrongInnerJoin_Model;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueA399_SetPropertyForPrivatePropertiesOfInheritors.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueA399_SetPropertyForPrivatePropertiesOfInheritors.cs
index 20befbc67..822f8a5b0 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueA399_SetPropertyForPrivatePropertiesOfInheritors.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueA399_SetPropertyForPrivatePropertiesOfInheritors.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2011.02.07
 
-using System;
 using System.Diagnostics;
 using System.Reflection;
 using NUnit.Framework;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueA401_AmbiguousMatchFoundException.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueA401_AmbiguousMatchFoundException.cs
index a5132b87e..2b7c7e446 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueA401_AmbiguousMatchFoundException.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueA401_AmbiguousMatchFoundException.cs
@@ -4,12 +4,10 @@
 // Created by: Alexis Kochetov
 // Created:    2011.02.07
 
-using System;
 using System.Diagnostics;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.IssueA401_AmbiguousMatchFoundException_Model;
-using System.Linq;
 using Xtensive.Orm.Validation;
 
 namespace Xtensive.Orm.Tests.Issues
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueA408_TargetException.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueA408_TargetException.cs
index a1500bff4..836c8e98a 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueA408_TargetException.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueA408_TargetException.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2011.02.07
 
-using System;
 using System.Diagnostics;
 using System.Reflection;
 using NUnit.Framework;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueA413_KeyNotFoundException.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueA413_KeyNotFoundException.cs
index 1ddce41f1..c1c3b7cff 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueA413_KeyNotFoundException.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueA413_KeyNotFoundException.cs
@@ -4,8 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2011.02.02
 
-using System;
-using System.Linq;
 using System.Diagnostics;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueA418_UnableToCompileModelWithPersistentInterface.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueA418_UnableToCompileModelWithPersistentInterface.cs
index 89e8dbcbe..8a2060447 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueA418_UnableToCompileModelWithPersistentInterface.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueA418_UnableToCompileModelWithPersistentInterface.cs
@@ -4,12 +4,10 @@
 // Created by: Alexis Kochetov
 // Created:    2011.02.08
 
-using System;
 using System.Diagnostics;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.IssueA418_UnableToCompileModelWithPersistentInterface_Model;
-using System.Linq;
 
 namespace Xtensive.Orm.Tests.Issues
 {
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueA424_QueryByInterfaceException.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueA424_QueryByInterfaceException.cs
index b37dbde4e..a6da812e7 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueA424_QueryByInterfaceException.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueA424_QueryByInterfaceException.cs
@@ -4,13 +4,11 @@
 // Created by: Alexis Kochetov
 // Created:    2011.02.17
 
-using System;
 using System.Diagnostics;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Model;
 using Xtensive.Orm.Tests.Issues.IssueA424_QueryByInterfaceException_Model;
-using System.Linq;
 
 namespace Xtensive.Orm.Tests.Issues
 {
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueGitHub0070_IncludeProviderParameterConflictWithinParameterContext.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueGitHub0070_IncludeProviderParameterConflictWithinParameterContext.cs
index 79ae8fd5c..4d89becc9 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueGitHub0070_IncludeProviderParameterConflictWithinParameterContext.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueGitHub0070_IncludeProviderParameterConflictWithinParameterContext.cs
@@ -2,8 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Linq;
 using System.Reflection;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueGitHub0110_SimpleCommandProcessorOverridesOriginalException.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueGitHub0110_SimpleCommandProcessorOverridesOriginalException.cs
index 2c0243adb..44e0ce6c4 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueGitHub0110_SimpleCommandProcessorOverridesOriginalException.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueGitHub0110_SimpleCommandProcessorOverridesOriginalException.cs
@@ -2,12 +2,7 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Text;
-using System.Threading;
-using System.Threading.Tasks;
 using System.Transactions;
 using NUnit.Framework;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueGitHub0132_IncorrectInsertForSingleTableHierarchy.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueGitHub0132_IncorrectInsertForSingleTableHierarchy.cs
index 10f8bde7c..7229e66a3 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueGitHub0132_IncorrectInsertForSingleTableHierarchy.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueGitHub0132_IncorrectInsertForSingleTableHierarchy.cs
@@ -2,8 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Collections.Generic;
 using System.Text;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueGitHub071_DataReaderRemainsOpen.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueGitHub071_DataReaderRemainsOpen.cs
index bb751ad24..a48c2fef0 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueGitHub071_DataReaderRemainsOpen.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueGitHub071_DataReaderRemainsOpen.cs
@@ -2,9 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.IssueGitHub071_DataReaderRemainsOpenModel;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueGithub0048_CoalesceReturnsWrongResults.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueGithub0048_CoalesceReturnsWrongResults.cs
index d31777403..a58d56b75 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueGithub0048_CoalesceReturnsWrongResults.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueGithub0048_CoalesceReturnsWrongResults.cs
@@ -2,10 +2,7 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Collections.Generic;
 using System.Diagnostics.CodeAnalysis;
-using System.Linq;
 using System.Text;
 using NUnit.Framework;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueGithub0114_QueryRootReuseCauseNoRefJoin.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueGithub0114_QueryRootReuseCauseNoRefJoin.cs
index 007c8748d..c9d9b3412 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueGithub0114_QueryRootReuseCauseNoRefJoin.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueGithub0114_QueryRootReuseCauseNoRefJoin.cs
@@ -2,9 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Model;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueGithub0149_ParameterReplacerHandlesNullConstsIncorrectly.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueGithub0149_ParameterReplacerHandlesNullConstsIncorrectly.cs
index dba087e74..0caa11866 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueGithub0149_ParameterReplacerHandlesNullConstsIncorrectly.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueGithub0149_ParameterReplacerHandlesNullConstsIncorrectly.cs
@@ -2,9 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Text;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueGithub0164_ClosureReplacementForDescendantTypes.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueGithub0164_ClosureReplacementForDescendantTypes.cs
index e525fc0b5..0e90b6ab1 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueGithub0164_ClosureReplacementForDescendantTypes.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueGithub0164_ClosureReplacementForDescendantTypes.cs
@@ -2,9 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Text;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueGithub0171_ReadDateTimeOffsetFromPackedTuple.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueGithub0171_ReadDateTimeOffsetFromPackedTuple.cs
index 25c8fc0ae..04d5c78b9 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueGithub0171_ReadDateTimeOffsetFromPackedTuple.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueGithub0171_ReadDateTimeOffsetFromPackedTuple.cs
@@ -2,9 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Linq;
-using System.Threading.Tasks;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.IssueGithub0171_ReadDateTimeOffsetFromPackedTupleModel;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueGithub0224_DelayedQueryCapture.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueGithub0224_DelayedQueryCapture.cs
index 56ae7c26a..8168d8456 100755
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueGithub0224_DelayedQueryCapture.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueGithub0224_DelayedQueryCapture.cs
@@ -2,13 +2,10 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
 using System.Collections;
 using System.Diagnostics;
-using System.Linq;
 using System.Linq.Dynamic;
 using System.Reflection;
-using System.Threading;
 using NUnit.Framework;
 using Xtensive.Caching;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueGithub312_DefaultExpressionProblem.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueGithub312_DefaultExpressionProblem.cs
index af72111a6..702c58a39 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueGithub312_DefaultExpressionProblem.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueGithub312_DefaultExpressionProblem.cs
@@ -2,8 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Linq;
 using System.Linq.Expressions;
 using NUnit.Framework;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJIRA0003_OrderByStructureFieldLost.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJIRA0003_OrderByStructureFieldLost.cs
index 9cf096da4..e89f18f4a 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJIRA0003_OrderByStructureFieldLost.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJIRA0003_OrderByStructureFieldLost.cs
@@ -4,12 +4,10 @@
 // Created by: Alexis Kochetov
 // Created:    2011.03.05
 
-using System;
 using System.Diagnostics;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.IssueJIRA0003_OrderByStructureFieldLost_Model;
-using System.Linq;
 
 namespace Xtensive.Orm.Tests.Issues
 {
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJIRA0020_CustomLINQCompilerContainerInterface.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJIRA0020_CustomLINQCompilerContainerInterface.cs
index 385dc1d85..b2860c81a 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJIRA0020_CustomLINQCompilerContainerInterface.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJIRA0020_CustomLINQCompilerContainerInterface.cs
@@ -4,8 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2011.03.03
 
-using System;
-using System.Linq;
 using System.Linq.Expressions;
 using NUnit.Framework;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJIRA0036_AutoTransactionsOpenModeDoesNotWork.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJIRA0036_AutoTransactionsOpenModeDoesNotWork.cs
index 46ab2d31e..835604bb5 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJIRA0036_AutoTransactionsOpenModeDoesNotWork.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJIRA0036_AutoTransactionsOpenModeDoesNotWork.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2011.03.14
 
-using System;
 using System.ComponentModel;
 using System.Diagnostics;
 using NUnit.Framework;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJIRA0085.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJIRA0085.cs
index f33270ae4..e091b65d2 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJIRA0085.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJIRA0085.cs
@@ -4,8 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2011.04.28
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.IssueJIRA0085_Model;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0042_IndexAttributeIsOmitted.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0042_IndexAttributeIsOmitted.cs
index 317f1e81b..6633c43f7 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0042_IndexAttributeIsOmitted.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0042_IndexAttributeIsOmitted.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2011.05.10
 
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.IssueJira0042_IndexAttributeIsOmitted_Model;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0071_DistinctDoesNotWorkProperly.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0071_DistinctDoesNotWorkProperly.cs
index 57745a134..c079a3712 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0071_DistinctDoesNotWorkProperly.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0071_DistinctDoesNotWorkProperly.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.01.25
 
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.IssueJira0071_DistinctDoesNotWorkProperlyModel;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0083_DtoMaterialization.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0083_DtoMaterialization.cs
index 4ee06e5e9..286f82166 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0083_DtoMaterialization.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0083_DtoMaterialization.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2011.04.26
 
-using System.Linq;
 using System.Linq.Dynamic;
 using NUnit.Framework;
 using Xtensive.Orm;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0102_NoForeignKeyOnInterfaceField.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0102_NoForeignKeyOnInterfaceField.cs
index 4b7a5115c..9709e691b 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0102_NoForeignKeyOnInterfaceField.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0102_NoForeignKeyOnInterfaceField.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2011.05.11
 
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.Issue0102_NoForeignKeyOnInterfaceField_Model;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0116_InterfacesCastAndIndexes.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0116_InterfacesCastAndIndexes.cs
index aa6e8cd19..d007e315d 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0116_InterfacesCastAndIndexes.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0116_InterfacesCastAndIndexes.cs
@@ -4,9 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2011.05.20
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.IssueJira0116_InterfacesCastAndIndexesModel;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0116_InterfacesCastAndIndexesModel/Generated.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0116_InterfacesCastAndIndexesModel/Generated.cs
index caef6da70..6460d1deb 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0116_InterfacesCastAndIndexesModel/Generated.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0116_InterfacesCastAndIndexesModel/Generated.cs
@@ -1,4 +1,3 @@
-using System;
 
 namespace Xtensive.Orm.Tests.Issues.IssueJira0116_InterfacesCastAndIndexesModel
 {
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0116_InterfacesCastAndIndexesModel/IRecord.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0116_InterfacesCastAndIndexesModel/IRecord.cs
index 5a9557bc6..145fdab3c 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0116_InterfacesCastAndIndexesModel/IRecord.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0116_InterfacesCastAndIndexesModel/IRecord.cs
@@ -1,4 +1,3 @@
-using System;
 
 namespace Xtensive.Orm.Tests.Issues.IssueJira0116_InterfacesCastAndIndexesModel
 {
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0116_InterfacesCastAndIndexesModel/Record.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0116_InterfacesCastAndIndexesModel/Record.cs
index 128e56960..6c7fb0381 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0116_InterfacesCastAndIndexesModel/Record.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0116_InterfacesCastAndIndexesModel/Record.cs
@@ -1,4 +1,3 @@
-using System;
 using Xtensive.Orm.Model;
 
 namespace Xtensive.Orm.Tests.Issues.IssueJira0116_InterfacesCastAndIndexesModel
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0117_FKStructureTest.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0117_FKStructureTest.cs
index 7e60143b2..8d4e5de7e 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0117_FKStructureTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0117_FKStructureTest.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2011.05.19
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Storage.MultipleFKViaStructureTestModel;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0149_LinqTranslationError.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0149_LinqTranslationError.cs
index 4b37b6abc..19669a18d 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0149_LinqTranslationError.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0149_LinqTranslationError.cs
@@ -4,8 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2011.06.21
 
-using System;
-using System.Linq;
 using System.Linq.Expressions;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0171_DateTimeOffset.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0171_DateTimeOffset.cs
index bff99b870..5a3fce13a 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0171_DateTimeOffset.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0171_DateTimeOffset.cs
@@ -4,8 +4,6 @@
 // Created by: Alena Mikshina
 // Created:    2013.11.27
 
-using System;
-using System.Linq;
 using System.Linq.Expressions;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0179_NullableBooleanFieldsQuery.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0179_NullableBooleanFieldsQuery.cs
index 6f561408c..ebcd8fd0d 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0179_NullableBooleanFieldsQuery.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0179_NullableBooleanFieldsQuery.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2011.09.23
 
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.IssueJira0179_NullableBooleanFieldsQueryModel;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0180_ChangeNullabilityViaUpgradeHints/ModelVersion1.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0180_ChangeNullabilityViaUpgradeHints/ModelVersion1.cs
index 803315a88..90d67a947 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0180_ChangeNullabilityViaUpgradeHints/ModelVersion1.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0180_ChangeNullabilityViaUpgradeHints/ModelVersion1.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2011.09.19
 
-using System;
 
 namespace Xtensive.Orm.Tests.Issues.IssueJira0180_ChangeNullabilityViaUpgradeHints.Model.Version1
 {
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0180_ChangeNullabilityViaUpgradeHints/ModelVersion2.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0180_ChangeNullabilityViaUpgradeHints/ModelVersion2.cs
index 8725c85a0..2ff7cdd39 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0180_ChangeNullabilityViaUpgradeHints/ModelVersion2.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0180_ChangeNullabilityViaUpgradeHints/ModelVersion2.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2011.09.19
 
-using System;
 
 namespace Xtensive.Orm.Tests.Issues.IssueJira0180_ChangeNullabilityViaUpgradeHints.Model.Version2
 {
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0180_ChangeNullabilityViaUpgradeHints/UpgradeTest.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0180_ChangeNullabilityViaUpgradeHints/UpgradeTest.cs
index 61df2fbad..884039a9c 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0180_ChangeNullabilityViaUpgradeHints/UpgradeTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0180_ChangeNullabilityViaUpgradeHints/UpgradeTest.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2011.09.19
 
-using System;
-using System.Linq;
 using System.Reflection;
 using Xtensive.Core;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0180_ChangeNullabilityViaUpgradeHints/Upgrader.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0180_ChangeNullabilityViaUpgradeHints/Upgrader.cs
index 8247a3ed7..d1cfae2a4 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0180_ChangeNullabilityViaUpgradeHints/Upgrader.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0180_ChangeNullabilityViaUpgradeHints/Upgrader.cs
@@ -4,9 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2011.09.19
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Core;
 
 using Xtensive.Orm.Upgrade;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0187_TypeCastInContain.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0187_TypeCastInContain.cs
index 0820dc8e8..c2fb1d65b 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0187_TypeCastInContain.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0187_TypeCastInContain.cs
@@ -4,11 +4,9 @@
 // Created by: Dmitri Maximov
 // Created:    2011.09.06
 
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.Issue_TypeCastInContain_Model;
-using System.Collections.Generic;
 
 namespace Xtensive.Orm.Tests.Issues.Issue_TypeCastInContain_Model
 {
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0188_MissingFKsForComplexHierarchies.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0188_MissingFKsForComplexHierarchies.cs
index 8f100cd39..3d0bbeb1a 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0188_MissingFKsForComplexHierarchies.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0188_MissingFKsForComplexHierarchies.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2011.09.20
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Model;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0194_WrongResultWhenInClauseArgumentIsEmpty.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0194_WrongResultWhenInClauseArgumentIsEmpty.cs
index 56392fa48..e8cde92bc 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0194_WrongResultWhenInClauseArgumentIsEmpty.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0194_WrongResultWhenInClauseArgumentIsEmpty.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2011.09.22
 
-using System.Collections.Generic;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0195_DeleteAndCreateWithValidation.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0195_DeleteAndCreateWithValidation.cs
index 46ac76c83..61609ef48 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0195_DeleteAndCreateWithValidation.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0195_DeleteAndCreateWithValidation.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2011.09.23
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.IssueJira0195_DeleteAndCreateWithValidationModel;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0196_GuidAsTypeDiscriminator.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0196_GuidAsTypeDiscriminator.cs
index e4b36b98b..fd2131f16 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0196_GuidAsTypeDiscriminator.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0196_GuidAsTypeDiscriminator.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2011.09.27
 
-using System;
 using NUnit.Framework;
 using Xtensive.Reflection;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0202_OnRemoveActionOverriding.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0202_OnRemoveActionOverriding.cs
index 823180d54..abfa5daa5 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0202_OnRemoveActionOverriding.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0202_OnRemoveActionOverriding.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2011.11.18
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.IssueJira0202_OnRemoveActionOverriding_Model;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0208_IncorrectUpgradeSequence/ModelVersion1.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0208_IncorrectUpgradeSequence/ModelVersion1.cs
index 34b9bea2c..bac7dc62e 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0208_IncorrectUpgradeSequence/ModelVersion1.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0208_IncorrectUpgradeSequence/ModelVersion1.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.05.20
 
-using System;
 
 namespace Xtensive.Orm.Tests.Issues.IssueJira0208_IncorrectUpgradeSequence.Model.Version1
 {
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0208_IncorrectUpgradeSequence/ModelVersion2.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0208_IncorrectUpgradeSequence/ModelVersion2.cs
index 39f833413..dc4f394cc 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0208_IncorrectUpgradeSequence/ModelVersion2.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0208_IncorrectUpgradeSequence/ModelVersion2.cs
@@ -5,11 +5,9 @@
 // Created:    2009.05.20
 
 using System.Collections;
-using System.Linq;
 using Xtensive.Collections;
 using Xtensive.Core;
 using Xtensive.Orm.Upgrade;
-using System;
 
 namespace Xtensive.Orm.Tests.Issues.IssueJira0208_IncorrectUpgradeSequence.Model.Version2
 {
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0208_IncorrectUpgradeSequence/UpgradeTest.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0208_IncorrectUpgradeSequence/UpgradeTest.cs
index 87d6d3e09..08fd6233d 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0208_IncorrectUpgradeSequence/UpgradeTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0208_IncorrectUpgradeSequence/UpgradeTest.cs
@@ -4,8 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.05.20
 
-using System;
-using System.Linq;
 using System.Reflection;
 using Xtensive.Core;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0208_IncorrectUpgradeSequence/Upgrader.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0208_IncorrectUpgradeSequence/Upgrader.cs
index 3d53cff37..5d495db6b 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0208_IncorrectUpgradeSequence/Upgrader.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0208_IncorrectUpgradeSequence/Upgrader.cs
@@ -4,9 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.05.20
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Core;
 
 using Xtensive.Orm.Upgrade;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0213_GroupByNewDate.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0213_GroupByNewDate.cs
index 11c4586cf..b8084b565 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0213_GroupByNewDate.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0213_GroupByNewDate.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.01.25
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.IssueJira0213_GroupByNewDateModel;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0221_UnableToTranslateAggregate.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0221_UnableToTranslateAggregate.cs
index a467bd0a8..6cbdfd7ce 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0221_UnableToTranslateAggregate.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0221_UnableToTranslateAggregate.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2011.11.21
 
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Providers;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0222_GroupByBooleanColumn.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0222_GroupByBooleanColumn.cs
index bd7420104..59019d678 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0222_GroupByBooleanColumn.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0222_GroupByBooleanColumn.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2011.11.22
 
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.IssueJira0222_GroupByBooleanColumnModel;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0232_SupportForEnumHasFlag.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0232_SupportForEnumHasFlag.cs
index aadd67065..923a22b77 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0232_SupportForEnumHasFlag.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0232_SupportForEnumHasFlag.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2013.07.22
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.IssueJira0232_SupportForEnumHasFlageModel;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0238_GroupByGeneric.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0238_GroupByGeneric.cs
index 34a364427..2c3c4fea9 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0238_GroupByGeneric.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0238_GroupByGeneric.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.01.24
 
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.IssueIssueJira0238_GroupByGenericModel;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0240_SortingInSubqueryIsOmitted.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0240_SortingInSubqueryIsOmitted.cs
index 7555d67d8..fc3a753ef 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0240_SortingInSubqueryIsOmitted.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0240_SortingInSubqueryIsOmitted.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.01.25
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Providers;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0242_LegacyExecuteMethodsDoNotWork.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0242_LegacyExecuteMethodsDoNotWork.cs
index cabf0cd5c..0b66cb1c0 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0242_LegacyExecuteMethodsDoNotWork.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0242_LegacyExecuteMethodsDoNotWork.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.01.27
 
-using System.Collections.Generic;
-using System.Linq;
 using NUnit.Framework;
 using MetadataType = Xtensive.Orm.Metadata.Type;
 
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0243_PrefetchSyntaxSugar.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0243_PrefetchSyntaxSugar.cs
index 19bceedd6..816f64581 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0243_PrefetchSyntaxSugar.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0243_PrefetchSyntaxSugar.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.01.30
 
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.IssueJira0243_PrefetchSyntaxSugarModel;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0261_QuerySingleInsideDelayedCompiledQueries.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0261_QuerySingleInsideDelayedCompiledQueries.cs
index 7083db190..82b590f21 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0261_QuerySingleInsideDelayedCompiledQueries.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0261_QuerySingleInsideDelayedCompiledQueries.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2013.07.28
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.IssueJira0261_QuerySingleInsideDelayedCompiledQueriesModel;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0275_FilterComputedColumn.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0275_FilterComputedColumn.cs
index 2b092bd2c..037e1827d 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0275_FilterComputedColumn.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0275_FilterComputedColumn.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.01.31
 
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.IssueJira0275_FilterComputedColumnModel;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0314_IncorrectTransactionDisposing.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0314_IncorrectTransactionDisposing.cs
index 436813458..56bce81c8 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0314_IncorrectTransactionDisposing.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0314_IncorrectTransactionDisposing.cs
@@ -1,6 +1,3 @@
-using System.Linq;
-using System.Threading;
-using System.Threading.Tasks;
 using System.Transactions;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0330_MaterializationOfNullReference.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0330_MaterializationOfNullReference.cs
index e44dce7c0..e0a1bbdf4 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0330_MaterializationOfNullReference.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0330_MaterializationOfNullReference.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.02.17
 
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.IssueJira0330_MaterializationOfNullReferenceModel;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0339_PrefetchViaStructure.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0339_PrefetchViaStructure.cs
index 2fa48277c..d1e474b98 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0339_PrefetchViaStructure.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0339_PrefetchViaStructure.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.02.22
 
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Tests.Issues.IssueJira0339_PrefetchViaStructureModel;
 
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0346_OptimizeSessionSaveChangesWithoutInboundOnlyAndOutboundOnly.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0346_OptimizeSessionSaveChangesWithoutInboundOnlyAndOutboundOnly.cs
index 3d498685f..98fe8636d 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0346_OptimizeSessionSaveChangesWithoutInboundOnlyAndOutboundOnly.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0346_OptimizeSessionSaveChangesWithoutInboundOnlyAndOutboundOnly.cs
@@ -4,9 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2013.07.30
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Text;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0357_IndexWithInheritedFields.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0357_IndexWithInheritedFields.cs
index abd33ac8b..da69eb6f0 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0357_IndexWithInheritedFields.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0357_IndexWithInheritedFields.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2014.08.07
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Model;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0385_OracleExtractorFailure.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0385_OracleExtractorFailure.cs
index 0ea4db1c6..f3f92ca5d 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0385_OracleExtractorFailure.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0385_OracleExtractorFailure.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.04.18
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.IssueJira0385Model;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0416_NpgsqlBox.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0416_NpgsqlBox.cs
index 9df930f4d..50732bc5d 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0416_NpgsqlBox.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0416_NpgsqlBox.cs
@@ -4,7 +4,6 @@
 // Created by: Alena Mikshina
 // Created:    2014.05.05
 
-using System.Linq;
 using NpgsqlTypes;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0416_NpgsqlCircle.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0416_NpgsqlCircle.cs
index eb2a03d70..af3b7833b 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0416_NpgsqlCircle.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0416_NpgsqlCircle.cs
@@ -4,7 +4,6 @@
 // Created by: Alena Mikshina
 // Created:    2014.05.06
 
-using System.Linq;
 using NpgsqlTypes;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0416_NpgsqlLSeg.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0416_NpgsqlLSeg.cs
index b051b5d3f..f4b24e0d9 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0416_NpgsqlLSeg.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0416_NpgsqlLSeg.cs
@@ -4,7 +4,6 @@
 // Created by: Alena Mikshina
 // Created:    2014.05.06
 
-using System.Linq;
 using NpgsqlTypes;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0416_NpgsqlPath.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0416_NpgsqlPath.cs
index 314d2b723..cfac694a5 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0416_NpgsqlPath.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0416_NpgsqlPath.cs
@@ -4,7 +4,6 @@
 // Created by: Alena Mikshina
 // Created:    2014.05.06
 
-using System.Linq;
 using NpgsqlTypes;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0416_NpgsqlPoint.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0416_NpgsqlPoint.cs
index 4b00ec543..63cdcd5ce 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0416_NpgsqlPoint.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0416_NpgsqlPoint.cs
@@ -4,7 +4,6 @@
 // Created by: Alena Mikshina
 // Created:    2014.05.05
 
-using System.Linq;
 using NpgsqlTypes;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0416_NpgsqlPolygon.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0416_NpgsqlPolygon.cs
index 739741ef5..3f8892b0e 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0416_NpgsqlPolygon.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0416_NpgsqlPolygon.cs
@@ -4,7 +4,6 @@
 // Created by: Alena Mikshina
 // Created:    2014.05.06
 
-using System.Linq;
 using NpgsqlTypes;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0421_DateTimeAddXxx.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0421_DateTimeAddXxx.cs
index fcfe848da..7b878cad8 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0421_DateTimeAddXxx.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0421_DateTimeAddXxx.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2013.02.14
 
-using System;
-using System.Linq;
 using System.Linq.Expressions;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0424_DateTimeOperationInvalidSql.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0424_DateTimeOperationInvalidSql.cs
index 46d1e1762..a39ef3f61 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0424_DateTimeOperationInvalidSql.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0424_DateTimeOperationInvalidSql.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2013.01.31
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.IssueJira0424_DateTimeOperationInvalidSqlModel;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0425_DateTimeOperationError.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0425_DateTimeOperationError.cs
index a4b93fd63..8a21e565b 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0425_DateTimeOperationError.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0425_DateTimeOperationError.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2013.01.31
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.IssueJira0425_DateTimeOperationErrorModel;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0427_IndexOutOfRangeOnContainsOperation.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0427_IndexOutOfRangeOnContainsOperation.cs
index b0c76fb7b..ffa8b3df9 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0427_IndexOutOfRangeOnContainsOperation.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0427_IndexOutOfRangeOnContainsOperation.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2013.01.31
 
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.IssueJira0427_IndexOutOfRangeOnContainsOperationModel;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0430_PartialIndexOnBoolOrEnumFields.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0430_PartialIndexOnBoolOrEnumFields.cs
index 358d2f3f1..15c3f64cf 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0430_PartialIndexOnBoolOrEnumFields.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0430_PartialIndexOnBoolOrEnumFields.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2013.01.31
 
-using System;
 using System.Linq.Expressions;
 using NUnit.Framework;
 using Xtensive.Orm.Providers;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0431_IGroupingKeyIsNotUsable.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0431_IGroupingKeyIsNotUsable.cs
index 98e99afc6..6fe77884e 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0431_IGroupingKeyIsNotUsable.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0431_IGroupingKeyIsNotUsable.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2013.01.31
 
-using System;
-using System.Linq;
 using System.Runtime.Serialization;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0432_EnumTypeDiscriminator.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0432_EnumTypeDiscriminator.cs
index 2989886e4..2075bec9b 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0432_EnumTypeDiscriminator.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0432_EnumTypeDiscriminator.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2013.02.11
 
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.IssueJira0432_EnumTypeDiscriminatorModel;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0433_CompiledQueryOverEntitySet.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0433_CompiledQueryOverEntitySet.cs
index f333e7230..b088f5df4 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0433_CompiledQueryOverEntitySet.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0433_CompiledQueryOverEntitySet.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2013.02.13
 
-using System.Collections.Generic;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.IssueJira0433_CompiledQueryOverEntitySetModel;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0437_OperationsWithListOfInt.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0437_OperationsWithListOfInt.cs
index 5074aa50f..bb1db461f 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0437_OperationsWithListOfInt.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0437_OperationsWithListOfInt.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2013.02.22
 
-using System.Collections.Generic;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Providers;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0440_CustomCompilerLoosesImplicitCastToNullable.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0440_CustomCompilerLoosesImplicitCastToNullable.cs
index e0c959301..4e888bec6 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0440_CustomCompilerLoosesImplicitCastToNullable.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0440_CustomCompilerLoosesImplicitCastToNullable.cs
@@ -1,5 +1,3 @@
-using System;
-using System.Linq;
 using System.Linq.Expressions;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0441_EntitySetQueryFailsToTranslate.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0441_EntitySetQueryFailsToTranslate.cs
index bcce7e632..02f9eb20e 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0441_EntitySetQueryFailsToTranslate.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0441_EntitySetQueryFailsToTranslate.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2013.04.01
 
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.IssueJira0441_EntitySetQueryFailsToTranslateModel;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0442_AsQueryableExpressionInQuery.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0442_AsQueryableExpressionInQuery.cs
index bdcf92555..92b52175a 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0442_AsQueryableExpressionInQuery.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0442_AsQueryableExpressionInQuery.cs
@@ -4,9 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2013.04.29
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Linq.Expressions;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0443_FirstOrDefaultInSubqueryUsesWrongDefault.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0443_FirstOrDefaultInSubqueryUsesWrongDefault.cs
index abd1db497..642b1ed6d 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0443_FirstOrDefaultInSubqueryUsesWrongDefault.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0443_FirstOrDefaultInSubqueryUsesWrongDefault.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2013.04.30
 
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Providers;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0445_QueryForEntityWithEnumKey.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0445_QueryForEntityWithEnumKey.cs
index 7e98df378..5f749b478 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0445_QueryForEntityWithEnumKey.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0445_QueryForEntityWithEnumKey.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2013.05.21
 
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.IssueJira0445_QueryForEntityWithEnumKeyModel;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0446_TypeAsOnSubqueryOperand.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0446_TypeAsOnSubqueryOperand.cs
index 92df577b7..f3011752e 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0446_TypeAsOnSubqueryOperand.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0446_TypeAsOnSubqueryOperand.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2013.06.25
 
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Providers;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0449_RenameTableInNonDefaultDatabase.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0449_RenameTableInNonDefaultDatabase.cs
index 90191ea86..3fd22980b 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0449_RenameTableInNonDefaultDatabase.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0449_RenameTableInNonDefaultDatabase.cs
@@ -4,9 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2013.07.16
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Tests.Storage.Multimapping;
 using Xtensive.Orm.Upgrade;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0449_TimeSpanMinMaxValue.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0449_TimeSpanMinMaxValue.cs
index b275ae918..fb3f95766 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0449_TimeSpanMinMaxValue.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0449_TimeSpanMinMaxValue.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2013.07.02
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.IssueJira0449_TimeSpanMinMaxValueModel;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0459_SelfReferencingEntitiesRemove.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0459_SelfReferencingEntitiesRemove.cs
index 82b4bd2dc..d9d2bb64e 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0459_SelfReferencingEntitiesRemove.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0459_SelfReferencingEntitiesRemove.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2013.08.14
 
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.IssueJira0459_SelfReferencingEntitiesRemoveModel;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0471_LikeOperatorSupport.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0471_LikeOperatorSupport.cs
index 49f0619b9..f1a6d8871 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0471_LikeOperatorSupport.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0471_LikeOperatorSupport.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2013.08.12
 
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.IssueJira0471_LikeOperatorSupportModel;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0481_EntitySetCachesInvalidState.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0481_EntitySetCachesInvalidState.cs
index 882ff5ef7..bcd5a7c10 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0481_EntitySetCachesInvalidState.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0481_EntitySetCachesInvalidState.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2013.08.17
 
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.IssueJira0481_EntitySetCachesInvalidStateModel;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0500_OptimizeMultipleAggregatesWithProjections.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0500_OptimizeMultipleAggregatesWithProjections.cs
index 93dc31604..572782457 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0500_OptimizeMultipleAggregatesWithProjections.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0500_OptimizeMultipleAggregatesWithProjections.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2013.12.10
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Orm.Linq.Rewriters;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0516_PartialIndexConstruction.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0516_PartialIndexConstruction.cs
index 50d9843aa..5a69a3784 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0516_PartialIndexConstruction.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0516_PartialIndexConstruction.cs
@@ -4,7 +4,6 @@
 // Created by: Alena Mikshina
 // Created:    2014.02.13
 
-using System;
 using System.Linq.Expressions;
 using NUnit.Framework;
 using Xtensive.Orm.Model;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0519_StaleKeyInEntitySet.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0519_StaleKeyInEntitySet.cs
index ffb45ad44..9fbfaad05 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0519_StaleKeyInEntitySet.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0519_StaleKeyInEntitySet.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2014.02.09
 
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.IssueJira0519_StaleKeyInEntitySetModel;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0528_LongEnumBitOperations.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0528_LongEnumBitOperations.cs
index ad6a97259..d73d37e64 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0528_LongEnumBitOperations.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0528_LongEnumBitOperations.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2014.04.11
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Tests.Issues.IssueJira0528_LongEnumBitOperationsModel;
 
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0529_MultipleInOperations.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0529_MultipleInOperations.cs
index 6736f1d69..e96a3d048 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0529_MultipleInOperations.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0529_MultipleInOperations.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2014.05.21
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Tests.Issues.IssueJira0529_MultipleInOperationsTestModel;
 
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0531_IncorrectNameOfRecycledNestedType.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0531_IncorrectNameOfRecycledNestedType.cs
index d5d59b18b..2523c71af 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0531_IncorrectNameOfRecycledNestedType.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0531_IncorrectNameOfRecycledNestedType.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2014.05.21
 
-using System;
 using NUnit.Framework;
 using model1 = Xtensive.Orm.Tests.Issues.IssueJira0529_BugWithRecycledNestedV1;
 using model2 = Xtensive.Orm.Tests.Issues.IssueJira0529_BugWithRecycledNestedV2;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0537_DropDefaultConstraintBugTest.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0537_DropDefaultConstraintBugTest.cs
index 20dd741c4..552392f3b 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0537_DropDefaultConstraintBugTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0537_DropDefaultConstraintBugTest.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2013.12.30
 
-using System.Collections.Generic;
-using System.Linq;
 using System.Text;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0538_IncorrectSortedActionSequence.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0538_IncorrectSortedActionSequence.cs
index 6a9d1f764..bb4126d17 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0538_IncorrectSortedActionSequence.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0538_IncorrectSortedActionSequence.cs
@@ -4,9 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2014.06.05
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Text;
 using NUnit.Framework;
 using Xtensive.Orm.Tests.Issues.IssueJira0538_IncorrectSortedActionSequenceModel;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0540_IncorrectBehaviorOnDomainUpgradeWithRecycledTypeBug.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0540_IncorrectBehaviorOnDomainUpgradeWithRecycledTypeBug.cs
index c85f8ec52..add5dee2d 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0540_IncorrectBehaviorOnDomainUpgradeWithRecycledTypeBug.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0540_IncorrectBehaviorOnDomainUpgradeWithRecycledTypeBug.cs
@@ -4,9 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2014.06.04
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Text;
 using NUnit.Framework;
 using Xtensive.Orm.Upgrade;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0542_OfTypeTranslationBug.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0542_OfTypeTranslationBug.cs
index 98758984a..1a1c8ff4e 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0542_OfTypeTranslationBug.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0542_OfTypeTranslationBug.cs
@@ -4,9 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2014.07.25
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Text;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0546_IncorrectCachingOfQueries.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0546_IncorrectCachingOfQueries.cs
index 7d7a2c9fd..ffe8c5d28 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0546_IncorrectCachingOfQueries.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0546_IncorrectCachingOfQueries.cs
@@ -4,9 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2014.08.08
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Transactions;
 using NUnit.Framework;
 using Xtensive.Orm.Linq;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0550_IncorrectJoinSequenceTranslationInMySqlTest.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0550_IncorrectJoinSequenceTranslationInMySqlTest.cs
index 530c356d7..d33b3381b 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0550_IncorrectJoinSequenceTranslationInMySqlTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0550_IncorrectJoinSequenceTranslationInMySqlTest.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2014.09.01
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.IssueJira0550_IncorrectJoinSequenceTranslationInMySqlTestModel;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0553_IncorrectLeftJoinOnNotNullEntityField.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0553_IncorrectLeftJoinOnNotNullEntityField.cs
index 3356de077..e92e0ca5b 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0553_IncorrectLeftJoinOnNotNullEntityField.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0553_IncorrectLeftJoinOnNotNullEntityField.cs
@@ -4,9 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2014.09.08
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Text;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0556_ArithmeticExceptionWhenSubstractionOfDates.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0556_ArithmeticExceptionWhenSubstractionOfDates.cs
index 6b272011b..555b7fb8c 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0556_ArithmeticExceptionWhenSubstractionOfDates.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0556_ArithmeticExceptionWhenSubstractionOfDates.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2013.09.26
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Services;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0557_RollbackOfDifferentialTupleDifferenceWhenPersistFailed.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0557_RollbackOfDifferentialTupleDifferenceWhenPersistFailed.cs
index aff90a663..9264ff207 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0557_RollbackOfDifferentialTupleDifferenceWhenPersistFailed.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0557_RollbackOfDifferentialTupleDifferenceWhenPersistFailed.cs
@@ -4,9 +4,7 @@
 // Created by: Alexey Kulakov
 // Created:    2014.10.03
 
-using System;
 using System.Globalization;
-using System.Linq;
 using System.Transactions;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0558_InternalOperationForcedExecutionOfDelayedQueriesWithoutPersist.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0558_InternalOperationForcedExecutionOfDelayedQueriesWithoutPersist.cs
index 0909ce638..256b6d9d6 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0558_InternalOperationForcedExecutionOfDelayedQueriesWithoutPersist.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0558_InternalOperationForcedExecutionOfDelayedQueriesWithoutPersist.cs
@@ -4,9 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2014.10.20
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Reflection;
 using System.Text;
 using NUnit.Framework;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0563_IncorrectPersistActionSequence.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0563_IncorrectPersistActionSequence.cs
index c2e24193b..5e63746d3 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0563_IncorrectPersistActionSequence.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0563_IncorrectPersistActionSequence.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2014.10.27
 
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Validation;
 using model1 = Xtensive.Orm.Tests.Issues.IssueJira0563_IncorrectPersistActionSequenceModel1;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0566_IndexOnRemovableEntityBug.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0566_IndexOnRemovableEntityBug.cs
index 979ef4cda..9bf9cbc05 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0566_IndexOnRemovableEntityBug.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0566_IndexOnRemovableEntityBug.cs
@@ -4,9 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2014.11.26
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Text;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0570_InOperationDoesNotCreateTemporaryTable.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0570_InOperationDoesNotCreateTemporaryTable.cs
index 79e6285b5..fc5621642 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0570_InOperationDoesNotCreateTemporaryTable.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0570_InOperationDoesNotCreateTemporaryTable.cs
@@ -4,9 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2016.08.24
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Runtime.InteropServices;
 using NUnit.Framework;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0571_MySqlKeyGenerationProblem.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0571_MySqlKeyGenerationProblem.cs
index d47e4099e..85e96334f 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0571_MySqlKeyGenerationProblem.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0571_MySqlKeyGenerationProblem.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2015.02.03
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Providers;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0573_IncorrectMappingOfStructureFields.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0573_IncorrectMappingOfStructureFields.cs
index 8baef8405..8f4bf3117 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0573_IncorrectMappingOfStructureFields.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0573_IncorrectMappingOfStructureFields.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2015.02.02
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.IssueJira0573_IncorrectMappingOfStructureFieldsModel;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0577_EntityChangesRegistryIsNotEmptyAfterPersistFailed.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0577_EntityChangesRegistryIsNotEmptyAfterPersistFailed.cs
index 484a7b514..528ea875e 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0577_EntityChangesRegistryIsNotEmptyAfterPersistFailed.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0577_EntityChangesRegistryIsNotEmptyAfterPersistFailed.cs
@@ -4,9 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2015.03.18
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Text;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0584_IncorrectMappingOfColumnInQuery.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0584_IncorrectMappingOfColumnInQuery.cs
index b91c96a2a..cc0a09f9a 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0584_IncorrectMappingOfColumnInQuery.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0584_IncorrectMappingOfColumnInQuery.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2015.05.21
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0586_AnonymousTypeComparisonBug.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0586_AnonymousTypeComparisonBug.cs
index 7783e28a3..1da0679a9 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0586_AnonymousTypeComparisonBug.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0586_AnonymousTypeComparisonBug.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2015.05.28
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.IssueJira0586_AnonymousTypeComparisonBugModel;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0587_KeyComparisonBug.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0587_KeyComparisonBug.cs
index a5cb9251f..fe6ab6df0 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0587_KeyComparisonBug.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0587_KeyComparisonBug.cs
@@ -4,9 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2015.06.29
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Text;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0593_AggregateForSingleColumnTest.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0593_AggregateForSingleColumnTest.cs
index 4a194139c..25e4fe55a 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0593_AggregateForSingleColumnTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0593_AggregateForSingleColumnTest.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Groznov
 // Created:    2016.09.02
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Providers;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0604_SetOperationsWithDuplicateFieldsUsageFail.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0604_SetOperationsWithDuplicateFieldsUsageFail.cs
index e2f5142e9..defded21b 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0604_SetOperationsWithDuplicateFieldsUsageFail.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0604_SetOperationsWithDuplicateFieldsUsageFail.cs
@@ -4,9 +4,7 @@
 // Created by: Alexey Kulakov
 // Created:    2015.09.14
 
-using System;
 using System.Globalization;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0607_ColumnUselessRecreationsTest.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0607_ColumnUselessRecreationsTest.cs
index adf32fed0..df0191965 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0607_ColumnUselessRecreationsTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0607_ColumnUselessRecreationsTest.cs
@@ -1,5 +1,3 @@
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Modelling.Actions;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0609_RewritingQueriesInClosure.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0609_RewritingQueriesInClosure.cs
index d5ebc848d..9e27d67c1 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0609_RewritingQueriesInClosure.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0609_RewritingQueriesInClosure.cs
@@ -4,9 +4,7 @@
 // Created by: Alexey Kulakov
 // Created:    2009.11.02
 
-using System.Collections.Generic;
 using System.Globalization;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0612_NonPairedReferencesSearchBug.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0612_NonPairedReferencesSearchBug.cs
index 4802275a8..cd9bfaa0a 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0612_NonPairedReferencesSearchBug.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0612_NonPairedReferencesSearchBug.cs
@@ -1,5 +1,3 @@
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.IssueJira0612_ReferenceFinderBugModel;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0613_DataCleanUpInPerformSafely.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0613_DataCleanUpInPerformSafely.cs
index 3b451f3fa..e6a1c03ae 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0613_DataCleanUpInPerformSafely.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0613_DataCleanUpInPerformSafely.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2016.04.27
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Model;
 using userCase = Xtensive.Orm.Tests.Issues.IssueJira0613_DataCleanUpInPerformSafelyModel.UserCase;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0614_TypeMappingCachingInMaterializationContext.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0614_TypeMappingCachingInMaterializationContext.cs
index f9b80f8cc..d6df3e0d3 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0614_TypeMappingCachingInMaterializationContext.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0614_TypeMappingCachingInMaterializationContext.cs
@@ -2,10 +2,7 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
 using System.Diagnostics;
-using System.Collections.Generic;
-using System.Linq;
 using System.Text;
 using NUnit.Framework;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0616_ExistanceProviderProcessingBug.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0616_ExistanceProviderProcessingBug.cs
index 22d6e25d4..be0c5ad8d 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0616_ExistanceProviderProcessingBug.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0616_ExistanceProviderProcessingBug.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2015.12.04
 
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0617_IncorrectRemoveOfRedundantColumns.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0617_IncorrectRemoveOfRedundantColumns.cs
index 01c2df046..8c3f54d0c 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0617_IncorrectRemoveOfRedundantColumns.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0617_IncorrectRemoveOfRedundantColumns.cs
@@ -4,9 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2015.12.01
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Linq.Dynamic;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0619_InvalidExpressionInOrderBy.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0619_InvalidExpressionInOrderBy.cs
index 09f6ee784..7447f4d6d 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0619_InvalidExpressionInOrderBy.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0619_InvalidExpressionInOrderBy.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2015.12.08
 
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0627_FieldInitializationTest.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0627_FieldInitializationTest.cs
index ac5ad2d4a..0dec13f61 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0627_FieldInitializationTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0627_FieldInitializationTest.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2018.05.03
 
-using System;
-using System.Linq;
 using System.Linq.Expressions;
 using NUnit.Framework;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0627_PocoClassPropertyRenitialization.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0627_PocoClassPropertyRenitialization.cs
index bd6ddbc37..19bcd539f 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0627_PocoClassPropertyRenitialization.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0627_PocoClassPropertyRenitialization.cs
@@ -4,9 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2015.12.31
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Reflection;
 using NUnit.Framework;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0630_IncorrectColumnOrderOfPKIndexOfInterfaceTypes.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0630_IncorrectColumnOrderOfPKIndexOfInterfaceTypes.cs
index 09cdeeed9..e70c0c92f 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0630_IncorrectColumnOrderOfPKIndexOfInterfaceTypes.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0630_IncorrectColumnOrderOfPKIndexOfInterfaceTypes.cs
@@ -4,8 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2016.03.31
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.IssueJira0630_IncorrectColumnOrderOfPKIndexOfInterfaceTypesModel;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0636_SessionCacheTest.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0636_SessionCacheTest.cs
index 17f367fd3..6d12bb4bd 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0636_SessionCacheTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0636_SessionCacheTest.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Groznov
 // Created:    2016.05.16
 
-using System;
-using System.Collections.Generic;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Model;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0637_EntitySetFullOfNullsOnEnumeration.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0637_EntitySetFullOfNullsOnEnumeration.cs
index 36c3071f7..daa6f78ce 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0637_EntitySetFullOfNullsOnEnumeration.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0637_EntitySetFullOfNullsOnEnumeration.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2016.07.26
 
-using System.Linq;
-using System.Collections.Generic;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.IssueJira0637_EntitySetFullOfNullsOnEnumerationModel;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0641_IndexFilterExpressionTranslationBug.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0641_IndexFilterExpressionTranslationBug.cs
index 542edeca8..361a3e68b 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0641_IndexFilterExpressionTranslationBug.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0641_IndexFilterExpressionTranslationBug.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2016.08.09
 
-using System;
-using System.Linq;
 using System.Linq.Expressions;
 using NUnit.Framework;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0643_OracleDateTimeOffsetExtractionBug.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0643_OracleDateTimeOffsetExtractionBug.cs
index 853403c9f..4457fd7b5 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0643_OracleDateTimeOffsetExtractionBug.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0643_OracleDateTimeOffsetExtractionBug.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2016.04.29
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Providers;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0647_StoredDomainModelMappingsUpdateBug.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0647_StoredDomainModelMappingsUpdateBug.cs
index 80259559a..3c38d722d 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0647_StoredDomainModelMappingsUpdateBug.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0647_StoredDomainModelMappingsUpdateBug.cs
@@ -4,9 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2016.04.16
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0656_RemapRestoresRemovedReferences.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0656_RemapRestoresRemovedReferences.cs
index f398eedf7..3c113e5c9 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0656_RemapRestoresRemovedReferences.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0656_RemapRestoresRemovedReferences.cs
@@ -1,5 +1,3 @@
-using System;
-using System.Linq;
 using System.Runtime;
 using System.Runtime.InteropServices;
 using JetBrains.Annotations;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0659_EnumExpressionsAndConstantsTranslationBug.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0659_EnumExpressionsAndConstantsTranslationBug.cs
index b5020a635..54afb4aa8 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0659_EnumExpressionsAndConstantsTranslationBug.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0659_EnumExpressionsAndConstantsTranslationBug.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2016.08.08
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.IssueJira0659_GroupByConditionalExpressionWithEnumsModel;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0674_ReferenceFinderBug.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0674_ReferenceFinderBug.cs
index 8454221f4..3b121485d 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0674_ReferenceFinderBug.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0674_ReferenceFinderBug.cs
@@ -1,4 +1,3 @@
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.IssueJira0674_ReferenceFinderBugModel;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0675_EntityChangeRegistryDoesntClear.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0675_EntityChangeRegistryDoesntClear.cs
index 0daac39de..6d5c20a46 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0675_EntityChangeRegistryDoesntClear.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0675_EntityChangeRegistryDoesntClear.cs
@@ -2,10 +2,7 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Linq;
 using System.Reflection;
-using System.Threading;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Interfaces.Model;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0702_QueryingWithoutOpenedTransaction.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0702_QueryingWithoutOpenedTransaction.cs
index e9ee34ada..792f63766 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0702_QueryingWithoutOpenedTransaction.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0702_QueryingWithoutOpenedTransaction.cs
@@ -1,6 +1,3 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Text;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0708_StackOverflowOnDifferetialTupleMerge.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0708_StackOverflowOnDifferetialTupleMerge.cs
index db5574b7c..ce37b6469 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0708_StackOverflowOnDifferetialTupleMerge.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0708_StackOverflowOnDifferetialTupleMerge.cs
@@ -4,9 +4,7 @@
 // Created by: Alexey Kulakov
 // Created:    2017.09.06
 
-using System;
 using System.Diagnostics;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.IssueJira0708_StackOverflowOnDifferetialTupleMergeModel;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0710_IndirectStructureChildFKAbsence.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0710_IndirectStructureChildFKAbsence.cs
index 6012ea752..bb23845fb 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0710_IndirectStructureChildFKAbsence.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0710_IndirectStructureChildFKAbsence.cs
@@ -4,8 +4,6 @@
 // Created by: Julian Mamokin
 // Created:    2017.09.01
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Providers;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0712_IncorrectDefaultEnumValueTranslation.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0712_IncorrectDefaultEnumValueTranslation.cs
index 2ca1bfc24..6068a3d36 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0712_IncorrectDefaultEnumValueTranslation.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0712_IncorrectDefaultEnumValueTranslation.cs
@@ -4,7 +4,6 @@
 // Created by: Julian Mamokin
 // Created:    2017.09.15
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Model;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0718_EntitySetEnumerationBug.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0718_EntitySetEnumerationBug.cs
index 48f0c8c8c..a36c2fcd8 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0718_EntitySetEnumerationBug.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0718_EntitySetEnumerationBug.cs
@@ -4,9 +4,6 @@
 // Created by: Julian Mamokin
 // Created:    2017.12.22
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0723_ContainsOverLocalCollectionError.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0723_ContainsOverLocalCollectionError.cs
index f853453bd..cefd6a699 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0723_ContainsOverLocalCollectionError.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0723_ContainsOverLocalCollectionError.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kochetov
 // Created:    2018.01.31
 
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.IssueJira0723_IncludeFilterMappingGathererHandlesMemberExpressionBadlyModel;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0728_NullGroupHasNoElementsTest.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0728_NullGroupHasNoElementsTest.cs
index 10b0bfb01..44a825bc1 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0728_NullGroupHasNoElementsTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0728_NullGroupHasNoElementsTest.cs
@@ -4,10 +4,7 @@
 // Created by: Alexey Kulakov
 // Created:    2018.05.08
 
-using System;
-using System.Collections.Generic;
 using System.Data.Common;
-using System.Linq;
 using System.Linq.Expressions;
 using NUnit.Framework;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0735_WrongTypeIdsInValidateMode.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0735_WrongTypeIdsInValidateMode.cs
index f8ade435c..efba74ee3 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0735_WrongTypeIdsInValidateMode.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0735_WrongTypeIdsInValidateMode.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2018.06.17
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using V1 = Xtensive.Orm.Tests.Issues.IssueJira0735_WrongTypeIdsInValidateModeModel.V1;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0739_StructureFieldsRemapOnCastBug.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0739_StructureFieldsRemapOnCastBug.cs
index e06e75144..4fe0e38e2 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0739_StructureFieldsRemapOnCastBug.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0739_StructureFieldsRemapOnCastBug.cs
@@ -4,9 +4,6 @@
 // Created by: Denis Kudelin
 // Created:    2018.12.28
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Text;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0740_EntitySetFieldsRemapOnCastBug.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0740_EntitySetFieldsRemapOnCastBug.cs
index 6154bdc58..92557cba0 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0740_EntitySetFieldsRemapOnCastBug.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0740_EntitySetFieldsRemapOnCastBug.cs
@@ -4,9 +4,6 @@
 // Created by: Denis Kudelin
 // Created:    2018.12.26
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Text;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0742_QueryPreprocessorClosureExpressionSupport.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0742_QueryPreprocessorClosureExpressionSupport.cs
index 55a1a464c..ae963fca8 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0742_QueryPreprocessorClosureExpressionSupport.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0742_QueryPreprocessorClosureExpressionSupport.cs
@@ -2,8 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Linq;
 using System.Linq.Expressions;
 using NUnit.Framework;
 using NUnit.Framework.Constraints;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0743_IncludeDoesNotWorkWithSubqueries.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0743_IncludeDoesNotWorkWithSubqueries.cs
index aa53998fc..ae48fcda2 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0743_IncludeDoesNotWorkWithSubqueries.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0743_IncludeDoesNotWorkWithSubqueries.cs
@@ -4,9 +4,6 @@
 // Created by: Denis Kudelin
 // Created:    2018.10.18
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Linq.Expressions;
 using System.Text;
 using NUnit.Framework;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0746_LikeBehaviorDifferentOnClientSide.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0746_LikeBehaviorDifferentOnClientSide.cs
index 8c725e7e6..182da4173 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0746_LikeBehaviorDifferentOnClientSide.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0746_LikeBehaviorDifferentOnClientSide.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Kudelin
 // Created:    2018.25.10
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0752_RecycledAttributeDontWorkForPersistentGenericInterface.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0752_RecycledAttributeDontWorkForPersistentGenericInterface.cs
index b03259fcc..de797e9d6 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0752_RecycledAttributeDontWorkForPersistentGenericInterface.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0752_RecycledAttributeDontWorkForPersistentGenericInterface.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Kudelin
 // Created:    2018.12.24
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Modelling.Actions;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0759_UnableToTranslateOfTypeSelectExpression.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0759_UnableToTranslateOfTypeSelectExpression.cs
index a32015ea2..0e8da042c 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0759_UnableToTranslateOfTypeSelectExpression.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0759_UnableToTranslateOfTypeSelectExpression.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Kudelin
 // Created:    2019.01.31
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.IssueJira0759_UnableToTranslateOfTypeSelectExpressionModel;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0760_OverrideFieldNameAttributeRuinsFieldMappingOnUpgrade.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0760_OverrideFieldNameAttributeRuinsFieldMappingOnUpgrade.cs
index 34ad9daf6..a92434525 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0760_OverrideFieldNameAttributeRuinsFieldMappingOnUpgrade.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0760_OverrideFieldNameAttributeRuinsFieldMappingOnUpgrade.cs
@@ -2,9 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Text;
 using NUnit.Framework;
 using Xtensive.Orm.Building;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0761_ReadingAverageByDecimalField.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0761_ReadingAverageByDecimalField.cs
index dd373eb00..d3776f4c4 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0761_ReadingAverageByDecimalField.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0761_ReadingAverageByDecimalField.cs
@@ -4,9 +4,7 @@
 // Created by: Alexey Kulakov
 // Created:    2019.02.14
 
-using System;
 using System.Data.SqlTypes;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.IssueJira0761_ReadingAverageByDecimalFieldModel;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0767_OfTypeForNonGenericSources.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0767_OfTypeForNonGenericSources.cs
index 162f18cf7..595775c90 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0767_OfTypeForNonGenericSources.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0767_OfTypeForNonGenericSources.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2019.06.21
 
-using System.Linq;
 using System.Runtime.Serialization;
 using NUnit.Framework;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0768_NullableFieldsBecomeNonNullable.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0768_NullableFieldsBecomeNonNullable.cs
index 28ee8246e..105b56c03 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0768_NullableFieldsBecomeNonNullable.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0768_NullableFieldsBecomeNonNullable.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2019.07.17
 
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.IssueJira0768_NullableFieldsBecomeNonNullableModel;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0778_PrefetchStackOverflow.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0778_PrefetchStackOverflow.cs
index e602bfc12..3b48fbd2a 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0778_PrefetchStackOverflow.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0778_PrefetchStackOverflow.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2019.10.24
 
-using System;
-using System.Linq;
 using System.Text;
 using NUnit.Framework;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0779_SetOperationsWithOrderAndTakeWrongQuery.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0779_SetOperationsWithOrderAndTakeWrongQuery.cs
index 70a06c55c..dc0383bda 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0779_SetOperationsWithOrderAndTakeWrongQuery.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0779_SetOperationsWithOrderAndTakeWrongQuery.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2019.10.25
 
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Providers;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0781_CompositeKeyReferencesRemapOnCast.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0781_CompositeKeyReferencesRemapOnCast.cs
index 03dc7c69a..f469e70c5 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0781_CompositeKeyReferencesRemapOnCast.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0781_CompositeKeyReferencesRemapOnCast.cs
@@ -5,9 +5,6 @@
 // Created:    2019.12.16
 
 using NUnit.Framework;
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Text;
 using Xtensive.Core;
 using Xtensive.Orm.Linq;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0782_StorageSequenctialGeneratorBug.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0782_StorageSequenctialGeneratorBug.cs
index 979e5c9fd..95beb2732 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0782_StorageSequenctialGeneratorBug.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0782_StorageSequenctialGeneratorBug.cs
@@ -5,9 +5,6 @@
 // Created:    2019.12.16
 
 using NUnit.Framework;
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Text;
 using Xtensive.Orm.Building.Builders;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0784_IncludedTypeIdReferenceBreaksTypedIndexCompilation.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0784_IncludedTypeIdReferenceBreaksTypedIndexCompilation.cs
index 33ae05159..d937dd315 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0784_IncludedTypeIdReferenceBreaksTypedIndexCompilation.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0784_IncludedTypeIdReferenceBreaksTypedIndexCompilation.cs
@@ -5,9 +5,6 @@
 // Created:    2019.12.24
 
 using NUnit.Framework;
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Text;
 using Xtensive.Core;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0786_SqlServerAggregatesProblem/AggregatesProblemTestBase.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0786_SqlServerAggregatesProblem/AggregatesProblemTestBase.cs
index b3781aba0..484359833 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0786_SqlServerAggregatesProblem/AggregatesProblemTestBase.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0786_SqlServerAggregatesProblem/AggregatesProblemTestBase.cs
@@ -4,9 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2020.03.26
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Text;
 using Xtensive.Orm;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0786_SqlServerAggregatesProblem/AverageProcessingTest.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0786_SqlServerAggregatesProblem/AverageProcessingTest.cs
index 0bde414ae..4f1d27441 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0786_SqlServerAggregatesProblem/AverageProcessingTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0786_SqlServerAggregatesProblem/AverageProcessingTest.cs
@@ -5,9 +5,6 @@
 // Created:    2020.03.26
 
 using NUnit.Framework;
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Linq.Expressions;
 using System.Reflection;
 using System.Text;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0786_SqlServerAggregatesProblem/MaxProcessingTest.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0786_SqlServerAggregatesProblem/MaxProcessingTest.cs
index 548b1a475..b158c8e6f 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0786_SqlServerAggregatesProblem/MaxProcessingTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0786_SqlServerAggregatesProblem/MaxProcessingTest.cs
@@ -5,9 +5,6 @@
 // Created:    2020.03.26
 
 using NUnit.Framework;
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Linq.Expressions;
 using System.Reflection;
 using System.Text;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0786_SqlServerAggregatesProblem/MinProcessingTest.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0786_SqlServerAggregatesProblem/MinProcessingTest.cs
index 98d603d3d..74f772318 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0786_SqlServerAggregatesProblem/MinProcessingTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0786_SqlServerAggregatesProblem/MinProcessingTest.cs
@@ -5,9 +5,6 @@
 // Created:    2020.03.26
 
 using NUnit.Framework;
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Linq.Expressions;
 using System.Reflection;
 using System.Text;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0786_SqlServerAggregatesProblem/Model.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0786_SqlServerAggregatesProblem/Model.cs
index d07802dad..6c3f68a0c 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0786_SqlServerAggregatesProblem/Model.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0786_SqlServerAggregatesProblem/Model.cs
@@ -4,9 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2020.03.26
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Text;
 
 namespace Xtensive.Orm.Tests.Issues.IssueJira0786_SqlServerAggregatesProblem
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0786_SqlServerAggregatesProblem/SumProcessingTest.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0786_SqlServerAggregatesProblem/SumProcessingTest.cs
index 0b4932656..7548aa8b8 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0786_SqlServerAggregatesProblem/SumProcessingTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0786_SqlServerAggregatesProblem/SumProcessingTest.cs
@@ -5,9 +5,6 @@
 // Created:    2020.03.26
 
 using NUnit.Framework;
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Linq.Expressions;
 using System.Reflection;
 using System.Text;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0792_UnableToRemoveAssignedEntityWithNonNullableAssociationField.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0792_UnableToRemoveAssignedEntityWithNonNullableAssociationField.cs
index 121ee94a0..bc3fa5598 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0792_UnableToRemoveAssignedEntityWithNonNullableAssociationField.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0792_UnableToRemoveAssignedEntityWithNonNullableAssociationField.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2020.02.14
 
-using System;
-using System.Collections.Generic;
 using System.Text;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0793_FieldValidationTriggersLazyLoadFieldsFetch.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0793_FieldValidationTriggersLazyLoadFieldsFetch.cs
index 50a49ff18..d5e0c256e 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0793_FieldValidationTriggersLazyLoadFieldsFetch.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0793_FieldValidationTriggersLazyLoadFieldsFetch.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2020.02.18
 
-using System;
-using System.Collections.Generic;
 using System.Text;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Validation;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0795_EntitySetPrefetchDoesNotWork.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0795_EntitySetPrefetchDoesNotWork.cs
index f9ed87b2e..3d2388b07 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0795_EntitySetPrefetchDoesNotWork.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0795_EntitySetPrefetchDoesNotWork.cs
@@ -5,9 +5,6 @@
 // Created:    2020.02.19
 
 using NUnit.Framework;
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Reflection;
 using System.Text;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0796_IgnoreHintPathGetsInvalid.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0796_IgnoreHintPathGetsInvalid.cs
index 7397ea19c..84753e3f8 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0796_IgnoreHintPathGetsInvalid.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0796_IgnoreHintPathGetsInvalid.cs
@@ -5,9 +5,6 @@
 // Created:    2020.03.04
 
 using NUnit.Framework;
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Reflection;
 using System.Text;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0800_DtoInterfaceFieldInitializationWithinCtor.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0800_DtoInterfaceFieldInitializationWithinCtor.cs
index bf8f6e46e..d96de2f38 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0800_DtoInterfaceFieldInitializationWithinCtor.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0800_DtoInterfaceFieldInitializationWithinCtor.cs
@@ -3,8 +3,6 @@
 // See the License.txt file in the project root for more information.
 
 using NUnit.Framework;
-using System;
-using System.Linq;
 using Xtensive.Orm;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0801_ReduntandColumnRemoverRemovesPartOfTempTableColumns.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0801_ReduntandColumnRemoverRemovesPartOfTempTableColumns.cs
index 252612b43..84e896cf1 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0801_ReduntandColumnRemoverRemovesPartOfTempTableColumns.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0801_ReduntandColumnRemoverRemovesPartOfTempTableColumns.cs
@@ -5,9 +5,6 @@
 // Created:    2020.11.16
 
 using NUnit.Framework;
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.IssueJira0801_ReduntandColumnRemoverRemovesPartOfTempTableColumnsModel;
 
diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira_0530_LowSpeedDecimalMaterializationCouseSqlDecimalInternalException.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira_0530_LowSpeedDecimalMaterializationCouseSqlDecimalInternalException.cs
index 70966d4fa..6b945b6dc 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/IssueJira_0530_LowSpeedDecimalMaterializationCouseSqlDecimalInternalException.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira_0530_LowSpeedDecimalMaterializationCouseSqlDecimalInternalException.cs
@@ -4,9 +4,7 @@
 // Created by: Alexey Kulakov
 // Created:    2015.04.22
 
-using System;
 using System.Diagnostics;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Services;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue_0694_SchemaUpgradeBug/ModelVersion1.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue_0694_SchemaUpgradeBug/ModelVersion1.cs
index de6ee6880..d22f5891e 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue_0694_SchemaUpgradeBug/ModelVersion1.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue_0694_SchemaUpgradeBug/ModelVersion1.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.05.20
 
-using System;
 using Xtensive.Core;
 
 namespace Xtensive.Orm.Tests.Issues.Issue_0694_SchemaUpgradeBug.Model.Version1
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue_0694_SchemaUpgradeBug/ModelVersion2.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue_0694_SchemaUpgradeBug/ModelVersion2.cs
index 3e34a4c89..c317471c9 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue_0694_SchemaUpgradeBug/ModelVersion2.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue_0694_SchemaUpgradeBug/ModelVersion2.cs
@@ -5,11 +5,9 @@
 // Created:    2009.05.20
 
 using System.Collections;
-using System.Linq;
 using Xtensive.Collections;
 using Xtensive.Core;
 using Xtensive.Orm.Upgrade;
-using System;
 
 namespace Xtensive.Orm.Tests.Issues.Issue_0694_SchemaUpgradeBug.Model.Version2
 {
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue_0694_SchemaUpgradeBug/ModelVersion3.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue_0694_SchemaUpgradeBug/ModelVersion3.cs
index c50971dff..d7af6d4f9 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue_0694_SchemaUpgradeBug/ModelVersion3.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue_0694_SchemaUpgradeBug/ModelVersion3.cs
@@ -5,11 +5,9 @@
 // Created:    2009.05.20
 
 using System.Collections;
-using System.Linq;
 using Xtensive.Collections;
 using Xtensive.Core;
 using Xtensive.Orm.Upgrade;
-using System;
 
 namespace Xtensive.Orm.Tests.Issues.Issue_0694_SchemaUpgradeBug.Model.Version3
 {
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue_0694_SchemaUpgradeBug/UpgradeTest.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue_0694_SchemaUpgradeBug/UpgradeTest.cs
index fe5f16dd3..ca285be86 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue_0694_SchemaUpgradeBug/UpgradeTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue_0694_SchemaUpgradeBug/UpgradeTest.cs
@@ -4,8 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.05.20
 
-using System;
-using System.Linq;
 using System.Reflection;
 using Xtensive.Core;
 using Xtensive.Orm.Tests.Issues.Issue_0694_SchemaUpgradeBug.Model.Version1;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue_0694_SchemaUpgradeBug/Upgrader.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue_0694_SchemaUpgradeBug/Upgrader.cs
index 0abc973b1..dda57819e 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue_0694_SchemaUpgradeBug/Upgrader.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue_0694_SchemaUpgradeBug/Upgrader.cs
@@ -4,9 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.05.20
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Core;
 using Xtensive.Orm.Upgrade;
 using M1 = Xtensive.Orm.Tests.Issues.Issue_0694_SchemaUpgradeBug.Model.Version1;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue_0716_UpgradeFailsInValidateMode/ModelVersion1.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue_0716_UpgradeFailsInValidateMode/ModelVersion1.cs
index 6a1eb455c..e76276398 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue_0716_UpgradeFailsInValidateMode/ModelVersion1.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue_0716_UpgradeFailsInValidateMode/ModelVersion1.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.05.20
 
-using System;
 
 namespace Xtensive.Orm.Tests.Issues.Issue_0716_UpgradeFailsInValidateMode.Model.Version1
 {
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue_0716_UpgradeFailsInValidateMode/ModelVersion2.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue_0716_UpgradeFailsInValidateMode/ModelVersion2.cs
index 94714c87f..f73abf683 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue_0716_UpgradeFailsInValidateMode/ModelVersion2.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue_0716_UpgradeFailsInValidateMode/ModelVersion2.cs
@@ -5,11 +5,9 @@
 // Created:    2009.05.20
 
 using System.Collections;
-using System.Linq;
 using Xtensive.Collections;
 using Xtensive.Core;
 using Xtensive.Orm.Upgrade;
-using System;
 
 namespace Xtensive.Orm.Tests.Issues.Issue_0716_UpgradeFailsInValidateMode.Model.Version2
 {
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue_0716_UpgradeFailsInValidateMode/UpgradeTest.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue_0716_UpgradeFailsInValidateMode/UpgradeTest.cs
index 9617dc9bb..2271ec9a1 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue_0716_UpgradeFailsInValidateMode/UpgradeTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue_0716_UpgradeFailsInValidateMode/UpgradeTest.cs
@@ -4,8 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.05.20
 
-using System;
-using System.Linq;
 using System.Reflection;
 using Xtensive.Core;
 using Xtensive.Orm.Tests.Issues.Issue_0716_UpgradeFailsInValidateMode.Model.Version1;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue_0716_UpgradeFailsInValidateMode/Upgrader.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue_0716_UpgradeFailsInValidateMode/Upgrader.cs
index a5bf9d345..811bf90fa 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue_0716_UpgradeFailsInValidateMode/Upgrader.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue_0716_UpgradeFailsInValidateMode/Upgrader.cs
@@ -4,9 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.05.20
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Core;
 using Xtensive.Orm.Upgrade;
 using M1 = Xtensive.Orm.Tests.Issues.Issue_0716_UpgradeFailsInValidateMode.Model.Version1;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue_0743_UpgradeToNonNullableTypes/ModelVersion1.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue_0743_UpgradeToNonNullableTypes/ModelVersion1.cs
index 89eaee2b1..b2a27f05a 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue_0743_UpgradeToNonNullableTypes/ModelVersion1.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue_0743_UpgradeToNonNullableTypes/ModelVersion1.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.05.20
 
-using System;
 
 namespace Xtensive.Orm.Tests.Issues.Issue_0743_UpgradeToNonNullableTypes.Model.Version1
 {
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue_0743_UpgradeToNonNullableTypes/ModelVersion2.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue_0743_UpgradeToNonNullableTypes/ModelVersion2.cs
index be285df7d..492613cf9 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue_0743_UpgradeToNonNullableTypes/ModelVersion2.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue_0743_UpgradeToNonNullableTypes/ModelVersion2.cs
@@ -5,11 +5,9 @@
 // Created:    2009.05.20
 
 using System.Collections;
-using System.Linq;
 using Xtensive.Collections;
 using Xtensive.Core;
 using Xtensive.Orm.Upgrade;
-using System;
 
 namespace Xtensive.Orm.Tests.Issues.Issue_0743_UpgradeToNonNullableTypes.Model.Version2
 {
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue_0743_UpgradeToNonNullableTypes/UpgradeTest.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue_0743_UpgradeToNonNullableTypes/UpgradeTest.cs
index e49bd9720..359ee201a 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue_0743_UpgradeToNonNullableTypes/UpgradeTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue_0743_UpgradeToNonNullableTypes/UpgradeTest.cs
@@ -4,8 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.05.20
 
-using System;
-using System.Linq;
 using System.Reflection;
 using Xtensive.Core;
 using Xtensive.Orm.Providers;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue_0743_UpgradeToNonNullableTypes/Upgrader.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue_0743_UpgradeToNonNullableTypes/Upgrader.cs
index 71f9e4b78..e00515b12 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue_0743_UpgradeToNonNullableTypes/Upgrader.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue_0743_UpgradeToNonNullableTypes/Upgrader.cs
@@ -4,9 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.05.20
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Core;
 
 using Xtensive.Orm.Tests.Issues.Issue_0743_UpgradeToNonNullableTypes.Model.Version2;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue_0769_ByteArrayColumnUpgrade/ModelVersion1.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue_0769_ByteArrayColumnUpgrade/ModelVersion1.cs
index d6f230fc3..7fa01394c 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue_0769_ByteArrayColumnUpgrade/ModelVersion1.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue_0769_ByteArrayColumnUpgrade/ModelVersion1.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.05.20
 
-using System;
 
 namespace Xtensive.Orm.Tests.Issues.Issue_0769_ByteArrayColumnUpgrade.Model.Version1
 {
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue_0769_ByteArrayColumnUpgrade/ModelVersion2.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue_0769_ByteArrayColumnUpgrade/ModelVersion2.cs
index f4f16e36d..9cef5f70d 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue_0769_ByteArrayColumnUpgrade/ModelVersion2.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue_0769_ByteArrayColumnUpgrade/ModelVersion2.cs
@@ -5,11 +5,9 @@
 // Created:    2009.05.20
 
 using System.Collections;
-using System.Linq;
 using Xtensive.Collections;
 using Xtensive.Core;
 using Xtensive.Orm.Upgrade;
-using System;
 
 namespace Xtensive.Orm.Tests.Issues.Issue_0769_ByteArrayColumnUpgrade.Model.Version2
 {
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue_0769_ByteArrayColumnUpgrade/UpgradeTest.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue_0769_ByteArrayColumnUpgrade/UpgradeTest.cs
index 08916f1eb..e059ee5b8 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue_0769_ByteArrayColumnUpgrade/UpgradeTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue_0769_ByteArrayColumnUpgrade/UpgradeTest.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.05.20
 
-using System.Linq;
 using System.Reflection;
 using NUnit.Framework;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue_0769_ByteArrayColumnUpgrade/Upgrader.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue_0769_ByteArrayColumnUpgrade/Upgrader.cs
index fbffb7a81..7fb791ce0 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue_0769_ByteArrayColumnUpgrade/Upgrader.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue_0769_ByteArrayColumnUpgrade/Upgrader.cs
@@ -4,9 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.05.20
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Core;
 using Xtensive.Orm.Providers;
 using Xtensive.Orm.Upgrade;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue_0837_HintGeneratorBug/ModelVersion1.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue_0837_HintGeneratorBug/ModelVersion1.cs
index bcf8fa098..159461a13 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue_0837_HintGeneratorBug/ModelVersion1.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue_0837_HintGeneratorBug/ModelVersion1.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.05.20
 
-using System;
 
 namespace Xtensive.Orm.Tests.Issues.Issue_0834_HintGeneratorBug.Model.Version1
 {
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue_0837_HintGeneratorBug/ModelVersion2.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue_0837_HintGeneratorBug/ModelVersion2.cs
index 19b31c296..c89c413db 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue_0837_HintGeneratorBug/ModelVersion2.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue_0837_HintGeneratorBug/ModelVersion2.cs
@@ -6,7 +6,6 @@
 
 using Xtensive.Core;
 using Xtensive.Orm.Upgrade;
-using System;
 
 namespace Xtensive.Orm.Tests.Issues.Issue_0834_HintGeneratorBug.Model.Version2
 {
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue_0837_HintGeneratorBug/UpgradeTest.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue_0837_HintGeneratorBug/UpgradeTest.cs
index 86559abb3..c5b953f20 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue_0837_HintGeneratorBug/UpgradeTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue_0837_HintGeneratorBug/UpgradeTest.cs
@@ -4,8 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.05.20
 
-using System;
-using System.Linq;
 using System.Reflection;
 using Xtensive.Core;
 using M1 = Xtensive.Orm.Tests.Issues.Issue_0834_HintGeneratorBug.Model.Version1;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue_0837_HintGeneratorBug/Upgrader.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue_0837_HintGeneratorBug/Upgrader.cs
index 262453186..0ba5a9f49 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue_0837_HintGeneratorBug/Upgrader.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue_0837_HintGeneratorBug/Upgrader.cs
@@ -4,9 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.05.20
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Core;
 
 using Xtensive.Orm.Upgrade;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue_0841_HintGeneratorBug/ModelVersion1.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue_0841_HintGeneratorBug/ModelVersion1.cs
index 2cb4499a3..1e95f9b01 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue_0841_HintGeneratorBug/ModelVersion1.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue_0841_HintGeneratorBug/ModelVersion1.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.05.20
 
-using System;
 
 namespace Xtensive.Orm.Tests.Issues.Issue_0841_HintGeneratorBug.Model.Version1
 {
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue_0841_HintGeneratorBug/ModelVersion2.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue_0841_HintGeneratorBug/ModelVersion2.cs
index 56d074b95..c95120960 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue_0841_HintGeneratorBug/ModelVersion2.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue_0841_HintGeneratorBug/ModelVersion2.cs
@@ -6,7 +6,6 @@
 
 using Xtensive.Core;
 using Xtensive.Orm.Upgrade;
-using System;
 
 namespace Xtensive.Orm.Tests.Issues.Issue_0841_HintGeneratorBug.Model.Version2
 {
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue_0841_HintGeneratorBug/UpgradeTest.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue_0841_HintGeneratorBug/UpgradeTest.cs
index a3666f0af..731140a5b 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue_0841_HintGeneratorBug/UpgradeTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue_0841_HintGeneratorBug/UpgradeTest.cs
@@ -4,8 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.05.20
 
-using System;
-using System.Linq;
 using System.Reflection;
 using Xtensive.Core;
 using M1 = Xtensive.Orm.Tests.Issues.Issue_0841_HintGeneratorBug.Model.Version1;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue_0841_HintGeneratorBug/Upgrader.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue_0841_HintGeneratorBug/Upgrader.cs
index 82900cabe..e3805ce04 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue_0841_HintGeneratorBug/Upgrader.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue_0841_HintGeneratorBug/Upgrader.cs
@@ -4,9 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.05.20
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Core;
 
 using Xtensive.Orm.Upgrade;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue_0841_HintGeneratorBug2/ModelVersion1.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue_0841_HintGeneratorBug2/ModelVersion1.cs
index fb1393a3b..3d3586bf0 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue_0841_HintGeneratorBug2/ModelVersion1.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue_0841_HintGeneratorBug2/ModelVersion1.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.05.20
 
-using System;
 
 namespace Xtensive.Orm.Tests.Issues.Issue_0841_HintGeneratorBug2.Model.Version1
 {
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue_0841_HintGeneratorBug2/ModelVersion2.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue_0841_HintGeneratorBug2/ModelVersion2.cs
index 59ad5f461..a7a3d915a 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue_0841_HintGeneratorBug2/ModelVersion2.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue_0841_HintGeneratorBug2/ModelVersion2.cs
@@ -6,7 +6,6 @@
 
 using Xtensive.Core;
 using Xtensive.Orm.Upgrade;
-using System;
 
 namespace Xtensive.Orm.Tests.Issues.Issue_0841_HintGeneratorBug2.Model.Version2
 {
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue_0841_HintGeneratorBug2/UpgradeTest.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue_0841_HintGeneratorBug2/UpgradeTest.cs
index 56fc14be3..1b94aabf8 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue_0841_HintGeneratorBug2/UpgradeTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue_0841_HintGeneratorBug2/UpgradeTest.cs
@@ -4,8 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.05.20
 
-using System;
-using System.Linq;
 using System.Reflection;
 using Xtensive.Core;
 using Xtensive.Orm.Providers;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue_0841_HintGeneratorBug2/Upgrader.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue_0841_HintGeneratorBug2/Upgrader.cs
index aa1333bca..d55397a82 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue_0841_HintGeneratorBug2/Upgrader.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue_0841_HintGeneratorBug2/Upgrader.cs
@@ -4,9 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.05.20
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Core;
 
 using Xtensive.Modelling.Comparison.Hints;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue_0841_HintGeneratorBug3/ModelVersion1.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue_0841_HintGeneratorBug3/ModelVersion1.cs
index ae780f4a1..50753983c 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue_0841_HintGeneratorBug3/ModelVersion1.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue_0841_HintGeneratorBug3/ModelVersion1.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.05.20
 
-using System;
 
 namespace Xtensive.Orm.Tests.Issues.Issue_0841_HintGeneratorBug3.Model.Version1
 {
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue_0841_HintGeneratorBug3/ModelVersion2.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue_0841_HintGeneratorBug3/ModelVersion2.cs
index cba26771d..83fa3771d 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue_0841_HintGeneratorBug3/ModelVersion2.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue_0841_HintGeneratorBug3/ModelVersion2.cs
@@ -6,7 +6,6 @@
 
 using Xtensive.Core;
 using Xtensive.Orm.Upgrade;
-using System;
 
 namespace Xtensive.Orm.Tests.Issues.Issue_0841_HintGeneratorBug3.Model.Version2
 {
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue_0841_HintGeneratorBug3/UpgradeTest.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue_0841_HintGeneratorBug3/UpgradeTest.cs
index 833174435..152afa92d 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue_0841_HintGeneratorBug3/UpgradeTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue_0841_HintGeneratorBug3/UpgradeTest.cs
@@ -4,8 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.05.20
 
-using System;
-using System.Linq;
 using System.Reflection;
 using Xtensive.Core;
 using M1 = Xtensive.Orm.Tests.Issues.Issue_0841_HintGeneratorBug3.Model.Version1;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue_0841_HintGeneratorBug3/Upgrader.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue_0841_HintGeneratorBug3/Upgrader.cs
index e5398d208..2854783f5 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue_0841_HintGeneratorBug3/Upgrader.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue_0841_HintGeneratorBug3/Upgrader.cs
@@ -4,10 +4,7 @@
 // Created by: Ivan Galkin
 // Created:    2009.05.20
 
-using System;
-using System.Collections.Generic;
 using Microsoft.Data.SqlClient;
-using System.Linq;
 using Xtensive.Core;
 using Xtensive.Orm.Services;
 using Xtensive.Orm.Upgrade;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue_0841_HintGeneratorBug4/ModelVersion1.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue_0841_HintGeneratorBug4/ModelVersion1.cs
index f18d4f0e4..389e0cfa0 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue_0841_HintGeneratorBug4/ModelVersion1.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue_0841_HintGeneratorBug4/ModelVersion1.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.05.20
 
-using System;
 
 namespace Xtensive.Orm.Tests.Issues.Issue_0841_HintGeneratorBug4.Model.Version1
 {
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue_0841_HintGeneratorBug4/ModelVersion2.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue_0841_HintGeneratorBug4/ModelVersion2.cs
index ef9e530c5..f953d1bc0 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue_0841_HintGeneratorBug4/ModelVersion2.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue_0841_HintGeneratorBug4/ModelVersion2.cs
@@ -6,7 +6,6 @@
 
 using Xtensive.Core;
 using Xtensive.Orm.Upgrade;
-using System;
 
 namespace Xtensive.Orm.Tests.Issues.Issue_0841_HintGeneratorBug4.Model.Version2
 {
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue_0841_HintGeneratorBug4/UpgradeTest.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue_0841_HintGeneratorBug4/UpgradeTest.cs
index bd386e596..a43431f73 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue_0841_HintGeneratorBug4/UpgradeTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue_0841_HintGeneratorBug4/UpgradeTest.cs
@@ -4,8 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.05.20
 
-using System;
-using System.Linq;
 using System.Reflection;
 using Xtensive.Core;
 using M1 = Xtensive.Orm.Tests.Issues.Issue_0841_HintGeneratorBug4.Model.Version1;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue_0841_HintGeneratorBug4/Upgrader.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue_0841_HintGeneratorBug4/Upgrader.cs
index a57aada16..0b0792db7 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue_0841_HintGeneratorBug4/Upgrader.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue_0841_HintGeneratorBug4/Upgrader.cs
@@ -4,9 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.05.20
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Core;
 
 using Xtensive.Orm.Upgrade;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/Issue_OfTypeMissesImplementors.cs b/Orm/Xtensive.Orm.Tests/Issues/Issue_OfTypeMissesImplementors.cs
index 5bd8fff4a..ed4e79358 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/Issue_OfTypeMissesImplementors.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/Issue_OfTypeMissesImplementors.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2011.08.21
 
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.Issue_OfTypeMissesImplementors_Model;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/KeyFormatBug.cs b/Orm/Xtensive.Orm.Tests/Issues/KeyFormatBug.cs
index 448bdad2f..8f3b5b75b 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/KeyFormatBug.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/KeyFormatBug.cs
@@ -4,13 +4,10 @@
 // Created by: Alex Yakunin
 // Created:    2010.06.11
 
-using System;
-using System.Collections.Generic;
 using System.Diagnostics;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Model;
-using System.Linq;
 
 namespace Xtensive.Orm.Tests.Issues.KeyFormatBug
 {
diff --git a/Orm/Xtensive.Orm.Tests/Issues/LocalCollectionsTest.cs b/Orm/Xtensive.Orm.Tests/Issues/LocalCollectionsTest.cs
index a57445435..7c468d1e3 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/LocalCollectionsTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/LocalCollectionsTest.cs
@@ -4,8 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2011.07.10
 
-using System.Collections.Generic;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.LocalCollectionsTest_Model;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/MaterializationMethodTest.cs b/Orm/Xtensive.Orm.Tests/Issues/MaterializationMethodTest.cs
index 7795fd4fc..32a45f685 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/MaterializationMethodTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/MaterializationMethodTest.cs
@@ -2,9 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.MaterializationMethodTestsModel;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/NotEqualsForNullableColumnTest.cs b/Orm/Xtensive.Orm.Tests/Issues/NotEqualsForNullableColumnTest.cs
index 2ed47c4c7..2a87c4020 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/NotEqualsForNullableColumnTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/NotEqualsForNullableColumnTest.cs
@@ -4,12 +4,10 @@
 // Created by: Alexis Kochetov
 // Created:    2011.03.25
 
-using System;
 using System.Diagnostics;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Issues.NotEqualsForNullableColumnTest_Model;
-using System.Linq;
 
 namespace Xtensive.Orm.Tests.Issues
 {
diff --git a/Orm/Xtensive.Orm.Tests/Issues/StrangeLockingExceptionTest.cs b/Orm/Xtensive.Orm.Tests/Issues/StrangeLockingExceptionTest.cs
index 061c76a76..e59abc5c0 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/StrangeLockingExceptionTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/StrangeLockingExceptionTest.cs
@@ -4,9 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.02.20
 
-using System;
-using System.Linq;
-using System.Threading.Tasks;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Providers;
diff --git a/Orm/Xtensive.Orm.Tests/Issues/StructureFieldRemoveTest.cs b/Orm/Xtensive.Orm.Tests/Issues/StructureFieldRemoveTest.cs
index 7ab716e2e..ab6b20897 100644
--- a/Orm/Xtensive.Orm.Tests/Issues/StructureFieldRemoveTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Issues/StructureFieldRemoveTest.cs
@@ -4,9 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.06.06
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Upgrade;
 using V1 = Xtensive.Orm.Tests.Issues.StructureFieldRemoveModel1;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/AggregateTest.cs b/Orm/Xtensive.Orm.Tests/Linq/AggregateTest.cs
index da0c85d49..18302e6f2 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/AggregateTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/AggregateTest.cs
@@ -4,8 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.02.04
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Tests;
 using Xtensive.Orm.Tests.ObjectModel;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/ArrayTest.cs b/Orm/Xtensive.Orm.Tests/Linq/ArrayTest.cs
index 12d4adbd5..fcc6bf830 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/ArrayTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/ArrayTest.cs
@@ -4,10 +4,7 @@
 // Created by: Alexey Gamzov
 // Created:    2009.04.30
 
-using System;
-using System.Collections.Generic;
 using System.Diagnostics;
-using System.Linq;
 using System.Reflection;
 using NUnit.Framework;
 using Xtensive.Comparison;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/CompiledQueriesWithClosureTest.cs b/Orm/Xtensive.Orm.Tests/Linq/CompiledQueriesWithClosureTest.cs
index 3e00d7792..6b1825104 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/CompiledQueriesWithClosureTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/CompiledQueriesWithClosureTest.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2013.12.16
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm;
 using CompiledQueriesWithClosureTestModel;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/ComplexTest.cs b/Orm/Xtensive.Orm.Tests/Linq/ComplexTest.cs
index c6facb117..205bc303d 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/ComplexTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/ComplexTest.cs
@@ -4,8 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.02.25
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Orm.Tests.ObjectModel;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/ConditionalTest.cs b/Orm/Xtensive.Orm.Tests/Linq/ConditionalTest.cs
index 83af18ca4..cb60d3ae0 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/ConditionalTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/ConditionalTest.cs
@@ -4,12 +4,10 @@
 // Created by: Alexey Gamzov
 // Created:    2009.04.21
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Linq.ConditionalTestModel;
 using Xtensive.Orm.Tests.Storage.ForeignKeys;
-using System.Linq;
 
 namespace Xtensive.Orm.Tests.Linq.ConditionalTestModel
 {
diff --git a/Orm/Xtensive.Orm.Tests/Linq/ContainsAnyAllTest.cs b/Orm/Xtensive.Orm.Tests/Linq/ContainsAnyAllTest.cs
index acfe07085..c059a1ce3 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/ContainsAnyAllTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/ContainsAnyAllTest.cs
@@ -4,9 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.02.04
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Providers;
 using Xtensive.Orm.Tests.ObjectModel;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/ContainsOverKeysCollectionTest.cs b/Orm/Xtensive.Orm.Tests/Linq/ContainsOverKeysCollectionTest.cs
index c330d881f..09ca9c44d 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/ContainsOverKeysCollectionTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/ContainsOverKeysCollectionTest.cs
@@ -4,10 +4,7 @@
 // Created by: Alexey Kulakov
 // Created:    2013.12.30
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Linq.ContainsOverKeysCollectionTestModel;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/ContainsTableTest.cs b/Orm/Xtensive.Orm.Tests/Linq/ContainsTableTest.cs
index 08f4566b8..b6deaac3a 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/ContainsTableTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/ContainsTableTest.cs
@@ -4,9 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2016.12.09
 
-using System;
-using System.Linq;
-using System.Threading;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Orm.Providers;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/ConvariantQueriesTest.cs b/Orm/Xtensive.Orm.Tests/Linq/ConvariantQueriesTest.cs
index 33015db84..1d0dc7e66 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/ConvariantQueriesTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/ConvariantQueriesTest.cs
@@ -4,9 +4,7 @@
 // Created by: Denis Krjuchkov
 // Created:    2011.11.02
 
-using System;
 using System.Diagnostics;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/CustomExpressionCompilers.cs b/Orm/Xtensive.Orm.Tests/Linq/CustomExpressionCompilers.cs
index d23f5a5ea..84a5944f6 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/CustomExpressionCompilers.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/CustomExpressionCompilers.cs
@@ -4,14 +4,12 @@
 // Created by: Alexey Gamzov
 // Created:    2009.11.13
 
-using System;
 using System.Linq.Expressions;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Linq;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Linq.CustomExpressionCompilersModel;
-using System.Linq;
 
 namespace Xtensive.Orm.Tests.Linq.CustomExpressionCompilersModel
 {
diff --git a/Orm/Xtensive.Orm.Tests/Linq/DataContextTest.cs b/Orm/Xtensive.Orm.Tests/Linq/DataContextTest.cs
index d4e4b4296..4984a80d9 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/DataContextTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/DataContextTest.cs
@@ -4,10 +4,7 @@
 // Created by: Alexey Gamzov
 // Created:    2009.12.02
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
-using System.Linq;
 using System.Linq.Expressions;
 using NUnit.Framework;
 using Xtensive.Orm.Tests;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/BaseTest.cs b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/BaseTest.cs
index dbb8671b4..00414f8a9 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/BaseTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/BaseTest.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2016.09.15
 
-using System;
-using System.Linq;
 using System.Linq.Expressions;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateOnly/ConstructorTest.cs b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateOnly/ConstructorTest.cs
index 13c5eb95a..2de2a4ce7 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateOnly/ConstructorTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateOnly/ConstructorTest.cs
@@ -2,8 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Orm.Tests.Linq.DateTimeAndDateTimeOffset.Model;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateOnly/DistinctTest.cs b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateOnly/DistinctTest.cs
index e08861fb7..eacd63c01 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateOnly/DistinctTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateOnly/DistinctTest.cs
@@ -2,8 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Linq;
 using System.Linq.Expressions;
 using NUnit.Framework;
 using Xtensive.Orm.Tests.Linq.DateTimeAndDateTimeOffset.Model;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateOnly/GroupByTest.cs b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateOnly/GroupByTest.cs
index 1d3d5389f..90fe5a06b 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateOnly/GroupByTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateOnly/GroupByTest.cs
@@ -2,8 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Linq;
 using System.Linq.Expressions;
 using NUnit.Framework;
 using Xtensive.Orm.Tests.Linq.DateTimeAndDateTimeOffset.Model;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateOnly/JoinTest.cs b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateOnly/JoinTest.cs
index 4c286e96d..95804a6da 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateOnly/JoinTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateOnly/JoinTest.cs
@@ -2,8 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Linq;
 using System.Linq.Expressions;
 using NUnit.Framework;
 using Xtensive.Orm.Tests.Linq.DateTimeAndDateTimeOffset.Model;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateOnly/MinMaxTest.cs b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateOnly/MinMaxTest.cs
index 215eec2de..d8b6b97f9 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateOnly/MinMaxTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateOnly/MinMaxTest.cs
@@ -2,8 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Linq;
 using System.Linq.Expressions;
 using NUnit.Framework;
 using Xtensive.Orm.Tests.Linq.DateTimeAndDateTimeOffset.Model;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateOnly/OperationsTest.cs b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateOnly/OperationsTest.cs
index cb732ef83..b07ca88fe 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateOnly/OperationsTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateOnly/OperationsTest.cs
@@ -2,7 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Tests.Linq.DateTimeAndDateTimeOffset.Model;
 
diff --git a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateOnly/OrderByTest.cs b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateOnly/OrderByTest.cs
index 857fffdbb..9cc9f4b48 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateOnly/OrderByTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateOnly/OrderByTest.cs
@@ -2,8 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Linq;
 using System.Linq.Expressions;
 using NUnit.Framework;
 using Xtensive.Orm.Tests.Linq.DateTimeAndDateTimeOffset.Model;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateOnly/PartsExtractionTest.cs b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateOnly/PartsExtractionTest.cs
index 5703e2a9b..affabf702 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateOnly/PartsExtractionTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateOnly/PartsExtractionTest.cs
@@ -2,7 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Tests.Linq.DateTimeAndDateTimeOffset.Model;
 
diff --git a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateOnly/WhereTest.cs b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateOnly/WhereTest.cs
index a235d8523..3825697c1 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateOnly/WhereTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateOnly/WhereTest.cs
@@ -2,8 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Linq;
 using System.Linq.Expressions;
 using NUnit.Framework;
 using Xtensive.Orm.Tests.Linq.DateTimeAndDateTimeOffset.Model;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateTime/ConstructorTest.cs b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateTime/ConstructorTest.cs
index 693037f7c..7978066f6 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateTime/ConstructorTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateTime/ConstructorTest.cs
@@ -2,8 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Orm.Tests.Linq.DateTimeAndDateTimeOffset.Model;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateTime/DistinctTest.cs b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateTime/DistinctTest.cs
index b4e4e6607..b6afd4dec 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateTime/DistinctTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateTime/DistinctTest.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Groznov
 // Created:    2016.08.01
 
-using System;
-using System.Linq;
 using System.Linq.Expressions;
 using NUnit.Framework;
 using Xtensive.Orm.Tests.Linq.DateTimeAndDateTimeOffset.Model;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateTime/GroupByTest.cs b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateTime/GroupByTest.cs
index b55afd4ba..c21004fd0 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateTime/GroupByTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateTime/GroupByTest.cs
@@ -2,8 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Linq;
 using System.Linq.Expressions;
 using NUnit.Framework;
 using Xtensive.Orm.Tests.Linq.DateTimeAndDateTimeOffset.Model;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateTime/JoinTest.cs b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateTime/JoinTest.cs
index 0c0b34bfa..cbfb4a485 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateTime/JoinTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateTime/JoinTest.cs
@@ -2,8 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Linq;
 using System.Linq.Expressions;
 using NUnit.Framework;
 using Xtensive.Orm.Tests.Linq.DateTimeAndDateTimeOffset.Model;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateTime/MinMaxTest.cs b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateTime/MinMaxTest.cs
index f00d2194b..a1da9332b 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateTime/MinMaxTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateTime/MinMaxTest.cs
@@ -2,8 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Linq;
 using System.Linq.Expressions;
 using NUnit.Framework;
 using Xtensive.Orm.Tests.Linq.DateTimeAndDateTimeOffset.Model;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateTime/OrderByTest.cs b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateTime/OrderByTest.cs
index ece14ffa9..acb3a5842 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateTime/OrderByTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateTime/OrderByTest.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Groznov
 // Created:    2016.08.01
 
-using System;
-using System.Linq;
 using System.Linq.Expressions;
 using NUnit.Framework;
 using Xtensive.Orm.Tests.Linq.DateTimeAndDateTimeOffset.Model;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateTime/PartsExtractionTest.cs b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateTime/PartsExtractionTest.cs
index 1d1b2a574..f13e58893 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateTime/PartsExtractionTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateTime/PartsExtractionTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Groznov
 // Created:    2016.08.01
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Tests.Linq.DateTimeAndDateTimeOffset.Model;
 
diff --git a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateTime/WhereTest.cs b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateTime/WhereTest.cs
index 596b0cb87..8b0cc8a87 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateTime/WhereTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateTime/WhereTest.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Groznov
 // Created:    2016.08.01
 
-using System;
-using System.Linq;
 using System.Linq.Expressions;
 using NUnit.Framework;
 using Xtensive.Orm.Tests.Linq.DateTimeAndDateTimeOffset.Model;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateTimeBaseTest.cs b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateTimeBaseTest.cs
index 85b19ff1a..6d7e85eff 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateTimeBaseTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateTimeBaseTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2016.09.15
 
-using System;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Linq.DateTimeAndDateTimeOffset.Model;
 
diff --git a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateTimeOffset/ComparisonTest.cs b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateTimeOffset/ComparisonTest.cs
index fd891d73e..2facbc42b 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateTimeOffset/ComparisonTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateTimeOffset/ComparisonTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Groznov
 // Created:    2016.08.01
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Tests.Linq.DateTimeAndDateTimeOffset.Model;
 
diff --git a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateTimeOffset/DateTimeOffsetConstructorTest.cs b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateTimeOffset/DateTimeOffsetConstructorTest.cs
index a0dd39a0a..70bcf76ab 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateTimeOffset/DateTimeOffsetConstructorTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateTimeOffset/DateTimeOffsetConstructorTest.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2016.09.09
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Providers;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateTimeOffset/DistinctTest.cs b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateTimeOffset/DistinctTest.cs
index 45930a07f..25a463b6c 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateTimeOffset/DistinctTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateTimeOffset/DistinctTest.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Groznov
 // Created:    2016.08.01
 
-using System;
-using System.Linq;
 using System.Linq.Expressions;
 using NUnit.Framework;
 using Xtensive.Orm.Tests.Linq.DateTimeAndDateTimeOffset.Model;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateTimeOffset/GroupByTest.cs b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateTimeOffset/GroupByTest.cs
index 943dc2c01..0a1437b85 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateTimeOffset/GroupByTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateTimeOffset/GroupByTest.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Groznov
 // Created:    2016.08.01
 
-using System;
-using System.Linq;
 using System.Linq.Expressions;
 using NUnit.Framework;
 using Xtensive.Orm.Tests.Linq.DateTimeAndDateTimeOffset.Model;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateTimeOffset/JoinTest.cs b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateTimeOffset/JoinTest.cs
index 3aeddb512..ea88f24bb 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateTimeOffset/JoinTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateTimeOffset/JoinTest.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Groznov
 // Created:    2016.08.01
 
-using System;
-using System.Linq;
 using System.Linq.Expressions;
 using NUnit.Framework;
 using Xtensive.Orm.Tests.Linq.DateTimeAndDateTimeOffset.Model;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateTimeOffset/MinMaxTest.cs b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateTimeOffset/MinMaxTest.cs
index 2c5e16b79..e3dc51d3f 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateTimeOffset/MinMaxTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateTimeOffset/MinMaxTest.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Groznov
 // Created:    2016.07.29
 
-using System;
-using System.Linq;
 using System.Linq.Expressions;
 using NUnit.Framework;
 using Xtensive.Orm.Tests.Linq.DateTimeAndDateTimeOffset.Model;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateTimeOffset/OperationsTest.cs b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateTimeOffset/OperationsTest.cs
index f02738374..bcc9b5757 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateTimeOffset/OperationsTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateTimeOffset/OperationsTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Groznov
 // Created:    2016.08.01
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Tests.Linq.DateTimeAndDateTimeOffset.Model;
 
diff --git a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateTimeOffset/OrderByTest.cs b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateTimeOffset/OrderByTest.cs
index 079a6e1d2..3901c083f 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateTimeOffset/OrderByTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateTimeOffset/OrderByTest.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Groznov
 // Created:    2016.07.29
 
-using System;
-using System.Linq;
 using System.Linq.Expressions;
 using NUnit.Framework;
 using Xtensive.Orm.Tests.Linq.DateTimeAndDateTimeOffset.Model;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateTimeOffset/PartsExtractionTest.cs b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateTimeOffset/PartsExtractionTest.cs
index 05d5b3239..24534344a 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateTimeOffset/PartsExtractionTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateTimeOffset/PartsExtractionTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Groznov
 // Created:    2016.08.01
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Tests.Linq.DateTimeAndDateTimeOffset.Model;
 
diff --git a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateTimeOffset/WhereTest.cs b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateTimeOffset/WhereTest.cs
index 5c73276e5..6b30644e8 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateTimeOffset/WhereTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateTimeOffset/WhereTest.cs
@@ -1,5 +1,3 @@
-using System;
-using System.Linq;
 using System.Linq.Expressions;
 using NUnit.Framework;
 using Xtensive.Orm.Tests.Linq.DateTimeAndDateTimeOffset.Model;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateTimeOffsetBaseTest.cs b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateTimeOffsetBaseTest.cs
index cd454cfa2..c0d95a637 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateTimeOffsetBaseTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/DateTimeOffsetBaseTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2016.09.15
 
-using System;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Providers;
 using Xtensive.Orm.Tests.Linq.DateTimeAndDateTimeOffset.Model;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/JoinResult{T}.cs b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/JoinResult{T}.cs
index c7034b49c..7f0bf7364 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/JoinResult{T}.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/JoinResult{T}.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Groznov
 // Created:    2016.08.01
 
-using System;
 
 namespace Xtensive.Orm.Tests.Linq.DateTimeAndDateTimeOffset
 {
diff --git a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/Model.cs b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/Model.cs
index cd6c8a03d..cadfd5966 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/Model.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/Model.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Groznov
 // Created:    2016.08.01
 
-using System;
 
 namespace Xtensive.Orm.Tests.Linq.DateTimeAndDateTimeOffset.Model
 {
diff --git a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/TimeOnly/ComparisonTestTimeOnly.cs b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/TimeOnly/ComparisonTestTimeOnly.cs
index a36e8382f..476575c84 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/TimeOnly/ComparisonTestTimeOnly.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/TimeOnly/ComparisonTestTimeOnly.cs
@@ -2,7 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Tests.Linq.DateTimeAndDateTimeOffset.Model;
 
diff --git a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/TimeOnly/ConstructorTest.cs b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/TimeOnly/ConstructorTest.cs
index 43760c611..d1d53f63e 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/TimeOnly/ConstructorTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/TimeOnly/ConstructorTest.cs
@@ -2,8 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Orm.Tests.Linq.DateTimeAndDateTimeOffset.Model;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/TimeOnly/DistinctTest.cs b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/TimeOnly/DistinctTest.cs
index e40a4330d..c15e8503c 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/TimeOnly/DistinctTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/TimeOnly/DistinctTest.cs
@@ -2,8 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Linq;
 using System.Linq.Expressions;
 using NUnit.Framework;
 using Xtensive.Orm.Tests.Linq.DateTimeAndDateTimeOffset.Model;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/TimeOnly/GroupByTest.cs b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/TimeOnly/GroupByTest.cs
index ae1986d5a..a32198a42 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/TimeOnly/GroupByTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/TimeOnly/GroupByTest.cs
@@ -2,8 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Linq;
 using System.Linq.Expressions;
 using NUnit.Framework;
 using Xtensive.Orm.Tests.Linq.DateTimeAndDateTimeOffset.Model;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/TimeOnly/JoinTest.cs b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/TimeOnly/JoinTest.cs
index a71c13f94..7e8f53dab 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/TimeOnly/JoinTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/TimeOnly/JoinTest.cs
@@ -2,8 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Linq;
 using System.Linq.Expressions;
 using NUnit.Framework;
 using Xtensive.Orm.Tests.Linq.DateTimeAndDateTimeOffset.Model;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/TimeOnly/MinMaxTest.cs b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/TimeOnly/MinMaxTest.cs
index a7b694b88..68abb3f44 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/TimeOnly/MinMaxTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/TimeOnly/MinMaxTest.cs
@@ -2,8 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Linq;
 using System.Linq.Expressions;
 using NUnit.Framework;
 using Xtensive.Orm.Tests.Linq.DateTimeAndDateTimeOffset.Model;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/TimeOnly/OperationsTest.cs b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/TimeOnly/OperationsTest.cs
index 0da689b0f..0f4101694 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/TimeOnly/OperationsTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/TimeOnly/OperationsTest.cs
@@ -2,7 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Tests.Linq.DateTimeAndDateTimeOffset.Model;
 
diff --git a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/TimeOnly/OrderByTest.cs b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/TimeOnly/OrderByTest.cs
index 8305ca83b..98ddaee9e 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/TimeOnly/OrderByTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/TimeOnly/OrderByTest.cs
@@ -2,8 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Linq;
 using System.Linq.Expressions;
 using NUnit.Framework;
 using Xtensive.Orm.Tests.Linq.DateTimeAndDateTimeOffset.Model;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/TimeOnly/PartsExtractionTest.cs b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/TimeOnly/PartsExtractionTest.cs
index d6e67fd16..c235a63a9 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/TimeOnly/PartsExtractionTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/TimeOnly/PartsExtractionTest.cs
@@ -2,7 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Tests.Linq.DateTimeAndDateTimeOffset.Model;
 
diff --git a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/TimeOnly/TimeOnlyToString.cs b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/TimeOnly/TimeOnlyToString.cs
index 90c34f629..f53f81095 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/TimeOnly/TimeOnlyToString.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/TimeOnly/TimeOnlyToString.cs
@@ -2,7 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
 using System.Linq.Expressions;
 using NUnit.Framework;
 using Xtensive.Orm.Tests.Linq.DateTimeAndDateTimeOffset.Model;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/TimeOnly/WhereTest.cs b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/TimeOnly/WhereTest.cs
index 486f3e12f..6545e1397 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/TimeOnly/WhereTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/DateTimeAndDateTimeOffset/TimeOnly/WhereTest.cs
@@ -2,8 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Linq;
 using System.Linq.Expressions;
 using NUnit.Framework;
 using Xtensive.Orm.Tests.Linq.DateTimeAndDateTimeOffset.Model;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/DistinctTest.cs b/Orm/Xtensive.Orm.Tests/Linq/DistinctTest.cs
index 822acb7ef..1dcc9d843 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/DistinctTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/DistinctTest.cs
@@ -4,8 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.02.04
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Providers;
 using Xtensive.Orm.Tests.ObjectModel;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/DoubleAggregateToStructTest.cs b/Orm/Xtensive.Orm.Tests/Linq/DoubleAggregateToStructTest.cs
index 165b46365..1f105eb26 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/DoubleAggregateToStructTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/DoubleAggregateToStructTest.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.04.26
 
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Linq.DoubleAggregateToStructTestModel;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/DynamicallyDefinedFields.cs b/Orm/Xtensive.Orm.Tests/Linq/DynamicallyDefinedFields.cs
index d49ac15dc..44031352d 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/DynamicallyDefinedFields.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/DynamicallyDefinedFields.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2014.06.24
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Building;
 using Xtensive.Orm.Building.Definitions;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/EntitySetTest.cs b/Orm/Xtensive.Orm.Tests/Linq/EntitySetTest.cs
index 99e4a5c39..4a6f95928 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/EntitySetTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/EntitySetTest.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.04.02
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Tests;
 using Xtensive.Orm.Linq;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/ExecuteTest.cs b/Orm/Xtensive.Orm.Tests/Linq/ExecuteTest.cs
index 31a791da1..edbff8ab0 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/ExecuteTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/ExecuteTest.cs
@@ -5,7 +5,6 @@
 // Created:    2009.12.15
 
 using System.Collections;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Linq;
 using Xtensive.Orm.Tests.ObjectModel;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/FirstSingleTest.cs b/Orm/Xtensive.Orm.Tests/Linq/FirstSingleTest.cs
index 121b007fc..0c2c3095a 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/FirstSingleTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/FirstSingleTest.cs
@@ -4,8 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.02.04
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Tests;
 using Xtensive.Orm.Linq;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/FreeTextTest.cs b/Orm/Xtensive.Orm.Tests/Linq/FreeTextTest.cs
index ddeb0932b..089635658 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/FreeTextTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/FreeTextTest.cs
@@ -4,14 +4,10 @@
 // Created by: Alexis Kochetov
 // Created:    2009.12.14
 
-using System;
-using System.Collections.Generic;
-using System.Threading;
 using NUnit.Framework;
 using Xtensive.Orm.Providers;
 using Xtensive.Orm.Tests.ObjectModel;
 using Xtensive.Orm.Tests.ObjectModel.ChinookDO;
-using System.Linq;
 
 namespace Xtensive.Orm.Tests.Linq
 {
diff --git a/Orm/Xtensive.Orm.Tests/Linq/FullTextColumnsDeclarationTest.cs b/Orm/Xtensive.Orm.Tests/Linq/FullTextColumnsDeclarationTest.cs
index 0bc5c38bc..a7f154714 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/FullTextColumnsDeclarationTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/FullTextColumnsDeclarationTest.cs
@@ -1,6 +1,3 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Linq.Expressions;
 using System.Text;
 using NUnit.Framework;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/GroupByTest.cs b/Orm/Xtensive.Orm.Tests/Linq/GroupByTest.cs
index 11e11d087..d1e9b533b 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/GroupByTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/GroupByTest.cs
@@ -4,9 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.02.04
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Tuples;
 using Xtensive.Orm.Providers;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/GroupByTwoEntitiesWithSameColumnsTest.cs b/Orm/Xtensive.Orm.Tests/Linq/GroupByTwoEntitiesWithSameColumnsTest.cs
index bb85d0846..b542fc438 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/GroupByTwoEntitiesWithSameColumnsTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/GroupByTwoEntitiesWithSameColumnsTest.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.12.06
 
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Linq.GroupByTwoEntitiesWithSameColumnsTestModel;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/InOverSubtypeColumnTest.cs b/Orm/Xtensive.Orm.Tests/Linq/InOverSubtypeColumnTest.cs
index 1111011ff..151ada8d8 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/InOverSubtypeColumnTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/InOverSubtypeColumnTest.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.12.07
 
-using System;
-using System.Linq;
 using System.Linq.Expressions;
 using NUnit.Framework;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/InTest.cs b/Orm/Xtensive.Orm.Tests/Linq/InTest.cs
index 05a57056c..ed01a4c4d 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/InTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/InTest.cs
@@ -4,10 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2009.09.30
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Threading.Tasks;
 using NUnit.Framework;
 using Xtensive.Orm.Providers;
 using Xtensive.Orm.Rse;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/IndexedMethodsTest.cs b/Orm/Xtensive.Orm.Tests/Linq/IndexedMethodsTest.cs
index 722c00dac..ee2dc00bf 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/IndexedMethodsTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/IndexedMethodsTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2009.12.14
 
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Providers;
 using Xtensive.Orm.Tests.ObjectModel;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/Interfaces/AlphabetTest.cs b/Orm/Xtensive.Orm.Tests/Linq/Interfaces/AlphabetTest.cs
index a12eb9674..4a294936a 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/Interfaces/AlphabetTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/Interfaces/AlphabetTest.cs
@@ -4,9 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.09.24
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/Interfaces/SimpleTest.cs b/Orm/Xtensive.Orm.Tests/Linq/Interfaces/SimpleTest.cs
index d0ee06a28..d1f397076 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/Interfaces/SimpleTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/Interfaces/SimpleTest.cs
@@ -4,9 +4,6 @@
 // Created by: Alexander Nikolaev
 // Created:    2009.06.01
 
-using System;
-using System.Linq;
-using System.Collections.Generic;
 using System.Linq.Expressions;
 using NUnit.Framework;
 using Xtensive.Collections;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/Interfaces/SlaveryTest.cs b/Orm/Xtensive.Orm.Tests/Linq/Interfaces/SlaveryTest.cs
index 2bb690c5e..c153803d4 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/Interfaces/SlaveryTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/Interfaces/SlaveryTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.09.24
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.ObjectModel.Interfaces.Slavery;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/JoinTest.cs b/Orm/Xtensive.Orm.Tests/Linq/JoinTest.cs
index dd60c3db2..19a4f53a1 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/JoinTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/JoinTest.cs
@@ -4,9 +4,6 @@
 // Created by: Alexey Kochetov
 // Created:    2008.12.17
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Comparison;
 using Xtensive.Orm.Tests;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/KeysUnionTest.cs b/Orm/Xtensive.Orm.Tests/Linq/KeysUnionTest.cs
index 8bcc89de7..508216a85 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/KeysUnionTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/KeysUnionTest.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.05.11
 
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Tests.Linq.KeysUnionTestModel;
 
diff --git a/Orm/Xtensive.Orm.Tests/Linq/LocalCollectionsComplexTest.cs b/Orm/Xtensive.Orm.Tests/Linq/LocalCollectionsComplexTest.cs
index cbbf24ecb..6f1cf88ff 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/LocalCollectionsComplexTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/LocalCollectionsComplexTest.cs
@@ -4,9 +4,6 @@
 // Created by: Alex Gamzov
 // Created:    2009.09.28
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Linq.LocalCollectionsComplexTestModel;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/LocalCollectionsTest.cs b/Orm/Xtensive.Orm.Tests/Linq/LocalCollectionsTest.cs
index 3e904820d..f3ff6cca6 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/LocalCollectionsTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/LocalCollectionsTest.cs
@@ -4,17 +4,13 @@
 // Created by: Alexey Gamzov
 // Created:    2009.09.07
 
-using System;
-using System.Collections.Generic;
 using NUnit.Framework;
-using System.Linq;
 using Xtensive.Orm.Providers;
 using Xtensive.Core;
 using Xtensive.Orm.Linq;
 using Xtensive.Orm.Tests.Linq.LocalCollectionsTest_Model;
 using Xtensive.Orm.Tests.ObjectModel;
 using Xtensive.Orm.Tests.ObjectModel.ChinookDO;
-using System.Threading.Tasks;
 
 namespace Xtensive.Orm.Tests.Linq.LocalCollectionsTest_Model
 {
diff --git a/Orm/Xtensive.Orm.Tests/Linq/LockTest.cs b/Orm/Xtensive.Orm.Tests/Linq/LockTest.cs
index 2f5d980d0..bfaa45409 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/LockTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/LockTest.cs
@@ -4,12 +4,7 @@
 // Created by: Alexey Gamzov
 // Created:    2009.08.25
 
-using System;
 using System.Collections.Concurrent;
-using System.Collections.Generic;
-using System.Linq;
-using System.Threading;
-using System.Threading.Tasks;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Orm.Providers;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/MemberCompilerProviderTest.Classes.cs b/Orm/Xtensive.Orm.Tests/Linq/MemberCompilerProviderTest.Classes.cs
index 66a1f8382..046a23305 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/MemberCompilerProviderTest.Classes.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/MemberCompilerProviderTest.Classes.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.02.10
 
-using System;
-using System.Collections.Generic;
 using System.Reflection;
 using Xtensive.Reflection;
 
diff --git a/Orm/Xtensive.Orm.Tests/Linq/MemberCompilerProviderTest.cs b/Orm/Xtensive.Orm.Tests/Linq/MemberCompilerProviderTest.cs
index 05fc91c3e..715ae885e 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/MemberCompilerProviderTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/MemberCompilerProviderTest.cs
@@ -4,9 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.02.10
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Reflection;
 using NUnit.Framework;
 using Xtensive.Orm.Linq.MemberCompilation;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/MiscTest.cs b/Orm/Xtensive.Orm.Tests/Linq/MiscTest.cs
index 3fc39fd5b..1403731f8 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/MiscTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/MiscTest.cs
@@ -5,8 +5,6 @@
 // Created:    2009.12.02
 
 
-using System;
-using System.Linq;
 using System.Linq.Expressions;
 using NUnit.Framework;
 using Xtensive.Collections;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/MsSamples/LinqToEntitiesSamples.cs b/Orm/Xtensive.Orm.Tests/Linq/MsSamples/LinqToEntitiesSamples.cs
index 1b33be70a..44676c5ec 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/MsSamples/LinqToEntitiesSamples.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/MsSamples/LinqToEntitiesSamples.cs
@@ -1,5 +1,3 @@
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Providers;
 using Xtensive.Orm.Tests.ObjectModel;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/MsSamples/LinqToSqlSamples.cs b/Orm/Xtensive.Orm.Tests/Linq/MsSamples/LinqToSqlSamples.cs
index d29e94afc..6127adfb7 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/MsSamples/LinqToSqlSamples.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/MsSamples/LinqToSqlSamples.cs
@@ -1,6 +1,3 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Providers;
 using Xtensive.Orm.Tests.ObjectModel;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/NestedCollectionsTest.cs b/Orm/Xtensive.Orm.Tests/Linq/NestedCollectionsTest.cs
index 763e53fea..e70bd8364 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/NestedCollectionsTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/NestedCollectionsTest.cs
@@ -5,7 +5,6 @@
 // Created:    2009.04.16
 
 using System.Collections;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Tests.ObjectModel;
 using Xtensive.Orm.Tests.ObjectModel.ChinookDO;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/NullableEnumMaterializationTest.cs b/Orm/Xtensive.Orm.Tests/Linq/NullableEnumMaterializationTest.cs
index 92a799f91..ed6c5ec80 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/NullableEnumMaterializationTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/NullableEnumMaterializationTest.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2013.12.13
 
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Tests.Linq.NullableEnumQueryTestModel;
 
diff --git a/Orm/Xtensive.Orm.Tests/Linq/OfTypeTest.cs b/Orm/Xtensive.Orm.Tests/Linq/OfTypeTest.cs
index 992cb8f05..e8aca38fb 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/OfTypeTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/OfTypeTest.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Kudelin
 // Created:    2019.01.31
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/OrderByTest.cs b/Orm/Xtensive.Orm.Tests/Linq/OrderByTest.cs
index ead835ac7..51a6bbeb4 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/OrderByTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/OrderByTest.cs
@@ -4,9 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2009.01.29
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Providers;
 using Xtensive.Orm.Tests.ObjectModel;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/PocoProjectionWithSubqueryTest.cs b/Orm/Xtensive.Orm.Tests/Linq/PocoProjectionWithSubqueryTest.cs
index faa799456..5caf9947a 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/PocoProjectionWithSubqueryTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/PocoProjectionWithSubqueryTest.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.06.13
 
-using System.Collections.Generic;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Linq.PocoProjectionWithSubqueryTestModel;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/ProjectToDtoWithInheritanceTest.cs b/Orm/Xtensive.Orm.Tests/Linq/ProjectToDtoWithInheritanceTest.cs
index dd01a7dcf..a829c7485 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/ProjectToDtoWithInheritanceTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/ProjectToDtoWithInheritanceTest.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.12.26
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Linq.ProjectToDtoWithInheritanceTestModel;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/QueryDumper.cs b/Orm/Xtensive.Orm.Tests/Linq/QueryDumper.cs
index 999e2a97f..7cd3569a7 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/QueryDumper.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/QueryDumper.cs
@@ -4,11 +4,8 @@
 // Created by: Alexey Gamzov
 // Created:    2009.03.27
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
 using System.Diagnostics;
-using System.Linq;
 using System.Reflection;
 using System.Runtime.CompilerServices;
 using System.Text;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/QueryMethodTests.cs b/Orm/Xtensive.Orm.Tests/Linq/QueryMethodTests.cs
index a1ad7ff5a..82e3ddc19 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/QueryMethodTests.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/QueryMethodTests.cs
@@ -4,9 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2010.01.15
 
-using System.Collections.Generic;
-using System.Linq;
-using System.Threading.Tasks;
 using NUnit.Framework;
 using Xtensive.Collections;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/QueryPreprocessorSortingTest.cs b/Orm/Xtensive.Orm.Tests/Linq/QueryPreprocessorSortingTest.cs
index ef69bcc65..b3ac664f4 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/QueryPreprocessorSortingTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/QueryPreprocessorSortingTest.cs
@@ -4,9 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.07.02
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Linq.Expressions;
 using NUnit.Framework;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/QueryRootOverriding.cs b/Orm/Xtensive.Orm.Tests/Linq/QueryRootOverriding.cs
index d70e8137d..4dab87c9b 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/QueryRootOverriding.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/QueryRootOverriding.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2011.11.02
 
-using System;
-using System.Linq;
 using System.Linq.Expressions;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/RefTest.cs b/Orm/Xtensive.Orm.Tests/Linq/RefTest.cs
index 05fc6c3b3..67f87b144 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/RefTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/RefTest.cs
@@ -4,11 +4,9 @@
 // Created by: Alexey Gamzov
 // Created:    2009.12.16
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Tests.ObjectModel;
 using Xtensive.Orm.Tests.ObjectModel.ChinookDO;
-using System.Linq;
 
 namespace Xtensive.Orm.Tests.Linq
 {
diff --git a/Orm/Xtensive.Orm.Tests/Linq/SearchConditionNodeVisitorTest.cs b/Orm/Xtensive.Orm.Tests/Linq/SearchConditionNodeVisitorTest.cs
index dee7a67d2..668ee81f0 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/SearchConditionNodeVisitorTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/SearchConditionNodeVisitorTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2016.12.08
 
-using System;
 using System.Linq.Expressions;
 using NUnit.Framework;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/SelectDtoTest.cs b/Orm/Xtensive.Orm.Tests/Linq/SelectDtoTest.cs
index b4fa75426..c0d951c54 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/SelectDtoTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/SelectDtoTest.cs
@@ -4,14 +4,12 @@
 // Created by: Alexis Kochetov
 // Created:    2010.02.18
 
-using System;
 using System.Diagnostics;
 using System.Linq.Expressions;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Providers;
 using Xtensive.Orm.Tests.Linq.Dto;
-using System.Linq;
 
 namespace Xtensive.Orm.Tests.Linq
 {
diff --git a/Orm/Xtensive.Orm.Tests/Linq/SelectManyTest.cs b/Orm/Xtensive.Orm.Tests/Linq/SelectManyTest.cs
index 381acae2a..a71eb6dbe 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/SelectManyTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/SelectManyTest.cs
@@ -4,9 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.04.01
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Orm.Providers;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/SelectTest.cs b/Orm/Xtensive.Orm.Tests/Linq/SelectTest.cs
index 0c218e418..6950798e9 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/SelectTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/SelectTest.cs
@@ -4,10 +4,7 @@
 // Created by: Alexey Kochetov
 // Created:    2009.01.12
 
-using System.Collections.Generic;
 using NUnit.Framework;
-using System;
-using System.Linq;
 using System.Reflection;
 using Xtensive.Core;
 using Xtensive.Tuples;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/SelectWithAccessToLocalCollectionTest.cs b/Orm/Xtensive.Orm.Tests/Linq/SelectWithAccessToLocalCollectionTest.cs
index bca8a17f0..abde316d8 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/SelectWithAccessToLocalCollectionTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/SelectWithAccessToLocalCollectionTest.cs
@@ -4,9 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2013.12.16
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Linq.SelectWithAccessToLocalCollectionTestModel;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/SetOperationsTest.cs b/Orm/Xtensive.Orm.Tests/Linq/SetOperationsTest.cs
index 2f78310d4..e55d74795 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/SetOperationsTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/SetOperationsTest.cs
@@ -4,8 +4,6 @@
 // Created by: Elena Vakhtina
 // Created:    2009.04.06
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Providers;
 using Xtensive.Orm.Tests.ObjectModel;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/SkipTakeElementAtTest.cs b/Orm/Xtensive.Orm.Tests/Linq/SkipTakeElementAtTest.cs
index e7746d134..bb92b01ae 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/SkipTakeElementAtTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/SkipTakeElementAtTest.cs
@@ -4,9 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2009.10.20
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Tests;
 using Xtensive.Orm.Linq;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/SortExpressionExtractorTest.cs b/Orm/Xtensive.Orm.Tests/Linq/SortExpressionExtractorTest.cs
index 366407f67..94eefbb61 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/SortExpressionExtractorTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/SortExpressionExtractorTest.cs
@@ -4,9 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2011.11.02
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Linq.Expressions;
 using NUnit.Framework;
 using Xtensive.Collections;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/SubqueryAndComputedColumnOptimizationTest.cs b/Orm/Xtensive.Orm.Tests/Linq/SubqueryAndComputedColumnOptimizationTest.cs
index e9b4b65be..ffbdd6a91 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/SubqueryAndComputedColumnOptimizationTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/SubqueryAndComputedColumnOptimizationTest.cs
@@ -4,9 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.08.27
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/SubqueryWithCalculatedFieldTest.cs b/Orm/Xtensive.Orm.Tests/Linq/SubqueryWithCalculatedFieldTest.cs
index 7a9d116f2..37758ed8b 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/SubqueryWithCalculatedFieldTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/SubqueryWithCalculatedFieldTest.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.06.21
 
-using System;
-using System.Linq;
 using System.Linq.Expressions;
 using NUnit.Framework;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/TagTest.cs b/Orm/Xtensive.Orm.Tests/Linq/TagTest.cs
index 54c80bd4c..8dce8cee6 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/TagTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/TagTest.cs
@@ -4,12 +4,8 @@
 // Created by: Edgar Isajanyan
 // Created:    2021.09.13
 
-using System;
 using System.Collections.Concurrent;
-using System.Collections.Generic;
-using System.Linq;
 using System.Text.RegularExpressions;
-using System.Threading.Tasks;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/TypeAsOptimizationTest.cs b/Orm/Xtensive.Orm.Tests/Linq/TypeAsOptimizationTest.cs
index 4d21f217d..770958b08 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/TypeAsOptimizationTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/TypeAsOptimizationTest.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.08.28
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Linq.TypeAsOptimizationTestModel;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/TypeCastAndInheritanceTest.cs b/Orm/Xtensive.Orm.Tests/Linq/TypeCastAndInheritanceTest.cs
index 01bbbda30..482523e24 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/TypeCastAndInheritanceTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/TypeCastAndInheritanceTest.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2009.04.10
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Tests;
 using Xtensive.Orm.Linq;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/WhereByEnumTest.cs b/Orm/Xtensive.Orm.Tests/Linq/WhereByEnumTest.cs
index c2e6063f9..f2b904d1a 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/WhereByEnumTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/WhereByEnumTest.cs
@@ -2,9 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Text;
 using NUnit.Framework;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm.Tests/Linq/WhereTest.cs b/Orm/Xtensive.Orm.Tests/Linq/WhereTest.cs
index fdf8e02e6..b221ef2ac 100644
--- a/Orm/Xtensive.Orm.Tests/Linq/WhereTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Linq/WhereTest.cs
@@ -4,9 +4,6 @@
 // Created by: Alexey Kochetov
 // Created:    2008.12.13
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Orm.Linq;
diff --git a/Orm/Xtensive.Orm.Tests/Model/AssociationTest.cs b/Orm/Xtensive.Orm.Tests/Model/AssociationTest.cs
index aa84b1f06..ecca6a4da 100644
--- a/Orm/Xtensive.Orm.Tests/Model/AssociationTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Model/AssociationTest.cs
@@ -13,9 +13,6 @@
 using Tuple = Xtensive.Tuples.Tuple;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Model.Association;
-using System.Linq;
-using System.Collections.Generic;
-using System;
 
 namespace Xtensive.Orm.Tests.Model.Association
 {
diff --git a/Orm/Xtensive.Orm.Tests/Model/AssociationsOverrideTest.cs b/Orm/Xtensive.Orm.Tests/Model/AssociationsOverrideTest.cs
index bd4861238..506cdcf8d 100644
--- a/Orm/Xtensive.Orm.Tests/Model/AssociationsOverrideTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Model/AssociationsOverrideTest.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.04.27
 
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Model.DiscardedAssociationsBugModel;
diff --git a/Orm/Xtensive.Orm.Tests/Model/AutoGenericsOverrideTest.cs b/Orm/Xtensive.Orm.Tests/Model/AutoGenericsOverrideTest.cs
index 5ed0fc28a..b0895f1d8 100644
--- a/Orm/Xtensive.Orm.Tests/Model/AutoGenericsOverrideTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Model/AutoGenericsOverrideTest.cs
@@ -1,4 +1,3 @@
-using System.Collections.Generic;
 using NUnit.Framework;
 using Xtensive.Orm.Building;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Model/CycleReferenceTest.cs b/Orm/Xtensive.Orm.Tests/Model/CycleReferenceTest.cs
index d0a980061..d7d1c6db7 100644
--- a/Orm/Xtensive.Orm.Tests/Model/CycleReferenceTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Model/CycleReferenceTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2009.04.16
 
-using System;
 using System.Reflection;
 using NUnit.Framework;
 
diff --git a/Orm/Xtensive.Orm.Tests/Model/CyclicContainedStructureTest.cs b/Orm/Xtensive.Orm.Tests/Model/CyclicContainedStructureTest.cs
index 033cc62f9..72ac440bb 100644
--- a/Orm/Xtensive.Orm.Tests/Model/CyclicContainedStructureTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Model/CyclicContainedStructureTest.cs
@@ -4,8 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2008.06.16
 
-using System;
-using System.Linq;
 using System.Reflection;
 using NUnit.Framework;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm.Tests/Model/CyclicHierarchyDependenciesTest.cs b/Orm/Xtensive.Orm.Tests/Model/CyclicHierarchyDependenciesTest.cs
index 118f49541..470dc51ed 100644
--- a/Orm/Xtensive.Orm.Tests/Model/CyclicHierarchyDependenciesTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Model/CyclicHierarchyDependenciesTest.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2008.12.12
 
-using System;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Model/DuplicatedIndexDueToGenericInterfaceTest.cs b/Orm/Xtensive.Orm.Tests/Model/DuplicatedIndexDueToGenericInterfaceTest.cs
index 5819e1227..85e03ca72 100644
--- a/Orm/Xtensive.Orm.Tests/Model/DuplicatedIndexDueToGenericInterfaceTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Model/DuplicatedIndexDueToGenericInterfaceTest.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.05.11
 
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Tests.Model.DuplicatedIndexDueToGenericInterfaceTestModel;
 
diff --git a/Orm/Xtensive.Orm.Tests/Model/FieldConverterTest.cs b/Orm/Xtensive.Orm.Tests/Model/FieldConverterTest.cs
index cd4266c31..eb0053370 100644
--- a/Orm/Xtensive.Orm.Tests/Model/FieldConverterTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Model/FieldConverterTest.cs
@@ -4,8 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2009.11.20
 
-using System;
-using System.Collections.Generic;
 using System.Collections.ObjectModel;
 using System.Collections.Specialized;
 using System.IO;
diff --git a/Orm/Xtensive.Orm.Tests/Model/FullText/DynamicallyDefinedFieldsAndIndexesTest.cs b/Orm/Xtensive.Orm.Tests/Model/FullText/DynamicallyDefinedFieldsAndIndexesTest.cs
index baa2956ed..b0aeb332c 100644
--- a/Orm/Xtensive.Orm.Tests/Model/FullText/DynamicallyDefinedFieldsAndIndexesTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Model/FullText/DynamicallyDefinedFieldsAndIndexesTest.cs
@@ -4,8 +4,6 @@
 // Created by: Julian Mamokin
 // Created:    2016.11.17
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Building;
 using Xtensive.Orm.Building.Definitions;
diff --git a/Orm/Xtensive.Orm.Tests/Model/FullText/IndexOnStructureFieldNamingTest.cs b/Orm/Xtensive.Orm.Tests/Model/FullText/IndexOnStructureFieldNamingTest.cs
index c898bd127..1e97619ea 100644
--- a/Orm/Xtensive.Orm.Tests/Model/FullText/IndexOnStructureFieldNamingTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Model/FullText/IndexOnStructureFieldNamingTest.cs
@@ -4,8 +4,6 @@
 // Created by: Julian Mamokin
 // Created:    2016.11.15
 
-using System.Collections.Generic;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Model/FullText/IndexOnStructureFieldTest.cs b/Orm/Xtensive.Orm.Tests/Model/FullText/IndexOnStructureFieldTest.cs
index 2f8292abb..696a46de2 100644
--- a/Orm/Xtensive.Orm.Tests/Model/FullText/IndexOnStructureFieldTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Model/FullText/IndexOnStructureFieldTest.cs
@@ -4,7 +4,6 @@
 // Created by: Julian Mamokin
 // Created:    2016.11.15
 
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Model;
diff --git a/Orm/Xtensive.Orm.Tests/Model/HierarchyTest.cs b/Orm/Xtensive.Orm.Tests/Model/HierarchyTest.cs
index 2347edf95..53bbf137b 100644
--- a/Orm/Xtensive.Orm.Tests/Model/HierarchyTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Model/HierarchyTest.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2007.12.26
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Building;
 using Xtensive.Orm.Building.Definitions;
diff --git a/Orm/Xtensive.Orm.Tests/Model/InheritanceSchemaTest.cs b/Orm/Xtensive.Orm.Tests/Model/InheritanceSchemaTest.cs
index ae90342c9..1c5304b08 100644
--- a/Orm/Xtensive.Orm.Tests/Model/InheritanceSchemaTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Model/InheritanceSchemaTest.cs
@@ -4,14 +4,12 @@
 // Created by: Alexey Kochetov
 // Created:    2007.11.30
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Building;
 using Xtensive.Orm.Building.Definitions;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Model;
 using Xtensive.Orm.Tests.Model.InheritanceSchemaModel;
-using System.Linq;
 
 namespace Xtensive.Orm.Tests.Model.InheritanceSchemaModel
 {
diff --git a/Orm/Xtensive.Orm.Tests/Model/InheritedKeyFieldTest.cs b/Orm/Xtensive.Orm.Tests/Model/InheritedKeyFieldTest.cs
index 02ddeb514..ab9aff2f9 100644
--- a/Orm/Xtensive.Orm.Tests/Model/InheritedKeyFieldTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Model/InheritedKeyFieldTest.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2008.12.12
 
-using System;
 using Xtensive.Orm;
 using Xtensive.Orm.Configuration;
 using InheritedKeyFieldModel;
diff --git a/Orm/Xtensive.Orm.Tests/Model/InterfaceAssociationsModelGenerator.cs b/Orm/Xtensive.Orm.Tests/Model/InterfaceAssociationsModelGenerator.cs
index 4dce149db..a2d8c742a 100644
--- a/Orm/Xtensive.Orm.Tests/Model/InterfaceAssociationsModelGenerator.cs
+++ b/Orm/Xtensive.Orm.Tests/Model/InterfaceAssociationsModelGenerator.cs
@@ -1,5 +1,3 @@
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm;
 
diff --git a/Orm/Xtensive.Orm.Tests/Model/LibraryTest.cs b/Orm/Xtensive.Orm.Tests/Model/LibraryTest.cs
index 47f1fd780..5d32bb367 100644
--- a/Orm/Xtensive.Orm.Tests/Model/LibraryTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Model/LibraryTest.cs
@@ -4,9 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2007.07.04
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Reflection;
 using NUnit.Framework;
 using Xtensive.Collections;
diff --git a/Orm/Xtensive.Orm.Tests/Model/MultidatabaseKeysTest.cs b/Orm/Xtensive.Orm.Tests/Model/MultidatabaseKeysTest.cs
index 4eb8f34b1..c3603c1c6 100644
--- a/Orm/Xtensive.Orm.Tests/Model/MultidatabaseKeysTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Model/MultidatabaseKeysTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2014.02.07
 
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Model;
diff --git a/Orm/Xtensive.Orm.Tests/Model/NameBuilderTest.cs b/Orm/Xtensive.Orm.Tests/Model/NameBuilderTest.cs
index 60a641961..3b9148209 100644
--- a/Orm/Xtensive.Orm.Tests/Model/NameBuilderTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Model/NameBuilderTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2020.02.06
 
-using System;
 using System.Reflection;
 using NUnit.Framework;
 using Xtensive.Core;
@@ -14,7 +13,6 @@
 using Xtensive.Orm.Weaving;
 using Xtensive.Reflection;
 using Xtensive.Orm.Building.Definitions;
-using System.Linq;
 
 namespace Xtensive.Orm.Tests.Model.NameBuilderTestModel
 {
diff --git a/Orm/Xtensive.Orm.Tests/Model/NonPublicFieldTest.cs b/Orm/Xtensive.Orm.Tests/Model/NonPublicFieldTest.cs
index cb7c1c848..943b30b81 100644
--- a/Orm/Xtensive.Orm.Tests/Model/NonPublicFieldTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Model/NonPublicFieldTest.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2009.09.14
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Model.NonPublicFieldTestModel;
diff --git a/Orm/Xtensive.Orm.Tests/Model/OnRemoveActionForNonPairedAssociationsTest.cs b/Orm/Xtensive.Orm.Tests/Model/OnRemoveActionForNonPairedAssociationsTest.cs
index f40877081..cc4dde7a0 100644
--- a/Orm/Xtensive.Orm.Tests/Model/OnRemoveActionForNonPairedAssociationsTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Model/OnRemoveActionForNonPairedAssociationsTest.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.04.26
 
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Model.OnRemoveActionForNonPairedAssociationsTestModel;
diff --git a/Orm/Xtensive.Orm.Tests/Model/PairTest.cs b/Orm/Xtensive.Orm.Tests/Model/PairTest.cs
index b495d9185..49fb26fa0 100644
--- a/Orm/Xtensive.Orm.Tests/Model/PairTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Model/PairTest.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2008.10.09
 
-using System;
 using System.Reflection;
 using NUnit.Framework;
 using Xtensive.Orm.Tests.PairModel;
diff --git a/Orm/Xtensive.Orm.Tests/Model/PersistentPropertyWeavingTest.cs b/Orm/Xtensive.Orm.Tests/Model/PersistentPropertyWeavingTest.cs
index 355b99958..0c19dfe53 100644
--- a/Orm/Xtensive.Orm.Tests/Model/PersistentPropertyWeavingTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Model/PersistentPropertyWeavingTest.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2013.09.13
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Model.PersistentPropertyWeavingTestModel;
diff --git a/Orm/Xtensive.Orm.Tests/Model/ReferencedKeys.cs b/Orm/Xtensive.Orm.Tests/Model/ReferencedKeys.cs
index c126d361c..e575afc8d 100644
--- a/Orm/Xtensive.Orm.Tests/Model/ReferencedKeys.cs
+++ b/Orm/Xtensive.Orm.Tests/Model/ReferencedKeys.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Kofman
 // Created:    2009.04.01
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Model.ReferencedKeysModel;
diff --git a/Orm/Xtensive.Orm.Tests/Model/SelfContainedStructureTest.cs b/Orm/Xtensive.Orm.Tests/Model/SelfContainedStructureTest.cs
index 6c6e34098..c3a37b37d 100644
--- a/Orm/Xtensive.Orm.Tests/Model/SelfContainedStructureTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Model/SelfContainedStructureTest.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2008.12.12
 
-using System;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Model/StringKeyTest.cs b/Orm/Xtensive.Orm.Tests/Model/StringKeyTest.cs
index 8b59bd984..785f7453d 100644
--- a/Orm/Xtensive.Orm.Tests/Model/StringKeyTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Model/StringKeyTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Kofman
 // Created:    2009.06.25
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Model.StringKeyTestModel;
diff --git a/Orm/Xtensive.Orm.Tests/Model/UselessTypeInTheMiddleTest.cs b/Orm/Xtensive.Orm.Tests/Model/UselessTypeInTheMiddleTest.cs
index 13e31c821..852f82fd5 100644
--- a/Orm/Xtensive.Orm.Tests/Model/UselessTypeInTheMiddleTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Model/UselessTypeInTheMiddleTest.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2010.03.04
 
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Model.UselessTypeInTheMiddleTestModel;
diff --git a/Orm/Xtensive.Orm.Tests/Model/VersionInfoTest.cs b/Orm/Xtensive.Orm.Tests/Model/VersionInfoTest.cs
index ac6139ae9..452a63bc7 100644
--- a/Orm/Xtensive.Orm.Tests/Model/VersionInfoTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Model/VersionInfoTest.cs
@@ -5,11 +5,9 @@
 // Created:    2009.08.13
 
 using System.Reflection;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Orm.Tests;
-using System;
 
 #region Models
 
diff --git a/Orm/Xtensive.Orm.Tests/ObjectModel/Chinook.cs b/Orm/Xtensive.Orm.Tests/ObjectModel/Chinook.cs
index 4653172bb..d9fa1e21c 100644
--- a/Orm/Xtensive.Orm.Tests/ObjectModel/Chinook.cs
+++ b/Orm/Xtensive.Orm.Tests/ObjectModel/Chinook.cs
@@ -4,9 +4,7 @@
 // Created by: Denis Kudelin
 // Created:    2019.09.19
 
-using System;
 using System.Diagnostics;
-using System.Linq;
 using Xtensive.Orm.Model;
 
 namespace Xtensive.Orm.Tests.ObjectModel.ChinookDO
diff --git a/Orm/Xtensive.Orm.Tests/ObjectModel/ChinookDO.cs b/Orm/Xtensive.Orm.Tests/ObjectModel/ChinookDO.cs
index 08d414c17..91b5199e6 100644
--- a/Orm/Xtensive.Orm.Tests/ObjectModel/ChinookDO.cs
+++ b/Orm/Xtensive.Orm.Tests/ObjectModel/ChinookDO.cs
@@ -4,10 +4,7 @@
 // Created by: Denis Kudelin
 // Created:    2019.09.19
 
-using System;
-using System.Collections.Generic;
 using System.Globalization;
-using System.Linq;
 using System.Xml.Linq;
 using Xtensive.Orm.Configuration;
 using IdEntity = System.ValueTuple<int,Xtensive.Orm.Entity>;
diff --git a/Orm/Xtensive.Orm.Tests/ObjectModel/ChinookDOModelTest.cs b/Orm/Xtensive.Orm.Tests/ObjectModel/ChinookDOModelTest.cs
index 3c5b50546..f1ec41104 100644
--- a/Orm/Xtensive.Orm.Tests/ObjectModel/ChinookDOModelTest.cs
+++ b/Orm/Xtensive.Orm.Tests/ObjectModel/ChinookDOModelTest.cs
@@ -5,9 +5,6 @@
 // Created:    2019.09.19
 
 using NUnit.Framework;
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Text;
 using Xtensive.Core;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/ObjectModel/Cms/AscxTemplate.cs b/Orm/Xtensive.Orm.Tests/ObjectModel/Cms/AscxTemplate.cs
index d6a984433..e04f8c5ca 100644
--- a/Orm/Xtensive.Orm.Tests/ObjectModel/Cms/AscxTemplate.cs
+++ b/Orm/Xtensive.Orm.Tests/ObjectModel/Cms/AscxTemplate.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Ilyin
 // Created:    2009.09.16
 
-using System;
 
 namespace Xtensive.Orm.Tests.ObjectModel.Cms
 {
diff --git a/Orm/Xtensive.Orm.Tests/ObjectModel/Cms/ContentDirectory.cs b/Orm/Xtensive.Orm.Tests/ObjectModel/Cms/ContentDirectory.cs
index c26a2cf85..e26826084 100644
--- a/Orm/Xtensive.Orm.Tests/ObjectModel/Cms/ContentDirectory.cs
+++ b/Orm/Xtensive.Orm.Tests/ObjectModel/Cms/ContentDirectory.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Ilyin
 // Created:    2009.08.31
 
-using System;
-using System.Linq;
 using System.Text;
 
 namespace Xtensive.Orm.Tests.ObjectModel.Cms
diff --git a/Orm/Xtensive.Orm.Tests/ObjectModel/Cms/ContentFile.cs b/Orm/Xtensive.Orm.Tests/ObjectModel/Cms/ContentFile.cs
index 8e7523c00..561953562 100644
--- a/Orm/Xtensive.Orm.Tests/ObjectModel/Cms/ContentFile.cs
+++ b/Orm/Xtensive.Orm.Tests/ObjectModel/Cms/ContentFile.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Ilyin
 // Created:    2009.08.31
 
-using System;
 
 namespace Xtensive.Orm.Tests.ObjectModel.Cms
 {
diff --git a/Orm/Xtensive.Orm.Tests/ObjectModel/Cms/ContentItem.cs b/Orm/Xtensive.Orm.Tests/ObjectModel/Cms/ContentItem.cs
index 764b8e56b..e4c01072c 100644
--- a/Orm/Xtensive.Orm.Tests/ObjectModel/Cms/ContentItem.cs
+++ b/Orm/Xtensive.Orm.Tests/ObjectModel/Cms/ContentItem.cs
@@ -5,7 +5,6 @@
 // Created:    2009.08.31
 
 
-using System;
 
 namespace Xtensive.Orm.Tests.ObjectModel.Cms
 {
diff --git a/Orm/Xtensive.Orm.Tests/ObjectModel/Cms/ContentReference.cs b/Orm/Xtensive.Orm.Tests/ObjectModel/Cms/ContentReference.cs
index 3d1132a6d..0b89fbf70 100644
--- a/Orm/Xtensive.Orm.Tests/ObjectModel/Cms/ContentReference.cs
+++ b/Orm/Xtensive.Orm.Tests/ObjectModel/Cms/ContentReference.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Ilyin
 // Created:    2009.12.14
 
-using System;
 
 namespace Xtensive.Orm.Tests.ObjectModel.Cms
 {
diff --git a/Orm/Xtensive.Orm.Tests/ObjectModel/Cms/HtmlContentItem.cs b/Orm/Xtensive.Orm.Tests/ObjectModel/Cms/HtmlContentItem.cs
index a84e2f9d0..51ed8c874 100644
--- a/Orm/Xtensive.Orm.Tests/ObjectModel/Cms/HtmlContentItem.cs
+++ b/Orm/Xtensive.Orm.Tests/ObjectModel/Cms/HtmlContentItem.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Ilyin
 // Created:    2009.09.15
 
-using System;
 
 namespace Xtensive.Orm.Tests.ObjectModel.Cms
 {
diff --git a/Orm/Xtensive.Orm.Tests/ObjectModel/Cms/Menu.cs b/Orm/Xtensive.Orm.Tests/ObjectModel/Cms/Menu.cs
index 4b1163de3..3aedd48bf 100644
--- a/Orm/Xtensive.Orm.Tests/ObjectModel/Cms/Menu.cs
+++ b/Orm/Xtensive.Orm.Tests/ObjectModel/Cms/Menu.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Ilyin
 // Created:    2009.09.16
 
-using System;
 
 namespace Xtensive.Orm.Tests.ObjectModel.Cms
 {
diff --git a/Orm/Xtensive.Orm.Tests/ObjectModel/Cms/NewsDirectory.cs b/Orm/Xtensive.Orm.Tests/ObjectModel/Cms/NewsDirectory.cs
index 7a153857d..6f5fe65ca 100644
--- a/Orm/Xtensive.Orm.Tests/ObjectModel/Cms/NewsDirectory.cs
+++ b/Orm/Xtensive.Orm.Tests/ObjectModel/Cms/NewsDirectory.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Ilyin
 // Created:    2009.12.14
 
-using System;
 
 namespace Xtensive.Orm.Tests.ObjectModel.Cms
 {
diff --git a/Orm/Xtensive.Orm.Tests/ObjectModel/Cms/NewsList.cs b/Orm/Xtensive.Orm.Tests/ObjectModel/Cms/NewsList.cs
index bff6bfd7f..98b12b740 100644
--- a/Orm/Xtensive.Orm.Tests/ObjectModel/Cms/NewsList.cs
+++ b/Orm/Xtensive.Orm.Tests/ObjectModel/Cms/NewsList.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Ilyin
 // Created:    2009.12.14
 
-using System;
 
 namespace Xtensive.Orm.Tests.ObjectModel.Cms
 {
diff --git a/Orm/Xtensive.Orm.Tests/ObjectModel/Cms/NewsPage.cs b/Orm/Xtensive.Orm.Tests/ObjectModel/Cms/NewsPage.cs
index 8eb764953..f01c181e8 100644
--- a/Orm/Xtensive.Orm.Tests/ObjectModel/Cms/NewsPage.cs
+++ b/Orm/Xtensive.Orm.Tests/ObjectModel/Cms/NewsPage.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Ilyin
 // Created:    2009.12.14
 
-using System;
 
 namespace Xtensive.Orm.Tests.ObjectModel.Cms
 {
diff --git a/Orm/Xtensive.Orm.Tests/ObjectModel/Cms/Page.cs b/Orm/Xtensive.Orm.Tests/ObjectModel/Cms/Page.cs
index 524821150..5b883d9d5 100644
--- a/Orm/Xtensive.Orm.Tests/ObjectModel/Cms/Page.cs
+++ b/Orm/Xtensive.Orm.Tests/ObjectModel/Cms/Page.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Ilyin
 // Created:    2009.08.31
 
-using System;
 
 namespace Xtensive.Orm.Tests.ObjectModel.Cms
 {
diff --git a/Orm/Xtensive.Orm.Tests/ObjectModel/Cms/PageTemplate.cs b/Orm/Xtensive.Orm.Tests/ObjectModel/Cms/PageTemplate.cs
index f60ddcdae..a49b63cd9 100644
--- a/Orm/Xtensive.Orm.Tests/ObjectModel/Cms/PageTemplate.cs
+++ b/Orm/Xtensive.Orm.Tests/ObjectModel/Cms/PageTemplate.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Ilyin
 // Created:    2009.08.31
 
-using System;
 
 namespace Xtensive.Orm.Tests.ObjectModel.Cms
 {
diff --git a/Orm/Xtensive.Orm.Tests/ObjectModel/Cms/WebSite.cs b/Orm/Xtensive.Orm.Tests/ObjectModel/Cms/WebSite.cs
index 240f19147..7944b7a96 100644
--- a/Orm/Xtensive.Orm.Tests/ObjectModel/Cms/WebSite.cs
+++ b/Orm/Xtensive.Orm.Tests/ObjectModel/Cms/WebSite.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Ilyin
 // Created:    2009.08.31
 
-using System;
 
 namespace Xtensive.Orm.Tests.ObjectModel.Cms
 {
diff --git a/Orm/Xtensive.Orm.Tests/ObjectModel/Cms/WebSiteUrl.cs b/Orm/Xtensive.Orm.Tests/ObjectModel/Cms/WebSiteUrl.cs
index 4963719b5..ca81a618c 100644
--- a/Orm/Xtensive.Orm.Tests/ObjectModel/Cms/WebSiteUrl.cs
+++ b/Orm/Xtensive.Orm.Tests/ObjectModel/Cms/WebSiteUrl.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Ilyin
 // Created:    2009.09.08
 
-using System;
 using Xtensive.Orm.Validation;
 
 namespace Xtensive.Orm.Tests.ObjectModel.Cms
diff --git a/Orm/Xtensive.Orm.Tests/ObjectModel/GenericModel.cs b/Orm/Xtensive.Orm.Tests/ObjectModel/GenericModel.cs
index 63c4df96f..7fd045891 100644
--- a/Orm/Xtensive.Orm.Tests/ObjectModel/GenericModel.cs
+++ b/Orm/Xtensive.Orm.Tests/ObjectModel/GenericModel.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.10.07
 
-using System;
 
 namespace Xtensive.Orm.Tests.ObjectModel.GenericModel
 {
diff --git a/Orm/Xtensive.Orm.Tests/ObjectModel/GraphModel.cs b/Orm/Xtensive.Orm.Tests/ObjectModel/GraphModel.cs
index 34efe7cfe..8357aefdf 100644
--- a/Orm/Xtensive.Orm.Tests/ObjectModel/GraphModel.cs
+++ b/Orm/Xtensive.Orm.Tests/ObjectModel/GraphModel.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2010.01.29
 
-using System;
 using System.Diagnostics;
 
 namespace Xtensive.Orm.Tests.ObjectModel.GraphModel
diff --git a/Orm/Xtensive.Orm.Tests/ObjectModel/Interfaces/Alphabet.cs b/Orm/Xtensive.Orm.Tests/ObjectModel/Interfaces/Alphabet.cs
index a988f35b1..e34ee5d0e 100644
--- a/Orm/Xtensive.Orm.Tests/ObjectModel/Interfaces/Alphabet.cs
+++ b/Orm/Xtensive.Orm.Tests/ObjectModel/Interfaces/Alphabet.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.09.24
 
-using System;
 using System.Diagnostics;
 using Xtensive.Orm.Model;
 
diff --git a/Orm/Xtensive.Orm.Tests/ObjectModel/Interfaces/Slavery.cs b/Orm/Xtensive.Orm.Tests/ObjectModel/Interfaces/Slavery.cs
index 21e7f2e90..b8e542330 100644
--- a/Orm/Xtensive.Orm.Tests/ObjectModel/Interfaces/Slavery.cs
+++ b/Orm/Xtensive.Orm.Tests/ObjectModel/Interfaces/Slavery.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.09.24
 
-using System;
 using System.Diagnostics;
 
 namespace Xtensive.Orm.Tests.ObjectModel.Interfaces.Slavery
diff --git a/Orm/Xtensive.Orm.Tests/Rse/IncludeProviderTest.cs b/Orm/Xtensive.Orm.Tests/Rse/IncludeProviderTest.cs
index 68be0ec15..6d9d149e8 100644
--- a/Orm/Xtensive.Orm.Tests/Rse/IncludeProviderTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Rse/IncludeProviderTest.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2009.10.27
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Core;
 using Tuple = Xtensive.Tuples.Tuple;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/AbstractGenericsTest.cs b/Orm/Xtensive.Orm.Tests/Storage/AbstractGenericsTest.cs
index ea4e24276..af5cf9f72 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/AbstractGenericsTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/AbstractGenericsTest.cs
@@ -4,9 +4,7 @@
 // Created by: Alexis Kochetov
 // Created:    2010.08.03
 
-using System;
 using System.Diagnostics;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Tests.Storage.AbstractGenericTest_Model;
 
diff --git a/Orm/Xtensive.Orm.Tests/Storage/ActivatorTest.cs b/Orm/Xtensive.Orm.Tests/Storage/ActivatorTest.cs
index a53fa6eb4..fa39715a0 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/ActivatorTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/ActivatorTest.cs
@@ -4,12 +4,10 @@
 // Created by: Nick Svetlov
 // Created:    2008.06.11
 
-using System;
 using System.Reflection;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Storage.ActivatorModel;
-using System.Linq;
 
 namespace Xtensive.Orm.Tests.Storage.ActivatorModel
 {
diff --git a/Orm/Xtensive.Orm.Tests/Storage/AggregateTest.cs b/Orm/Xtensive.Orm.Tests/Storage/AggregateTest.cs
index 49735b340..865ac4b76 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/AggregateTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/AggregateTest.cs
@@ -4,10 +4,7 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.04.28
 
-using System.Collections.Generic;
-using System.Linq;
 using NUnit.Framework;
-using System;
 
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Storage.DbTypeSupportModel;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/AnotherValidationTest.cs b/Orm/Xtensive.Orm.Tests/Storage/AnotherValidationTest.cs
index a5328dbd7..6aadd61a7 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/AnotherValidationTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/AnotherValidationTest.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2013.10.30
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Validation;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/ApplyTest.cs b/Orm/Xtensive.Orm.Tests/Storage/ApplyTest.cs
index c5173aefe..c629972e2 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/ApplyTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/ApplyTest.cs
@@ -4,9 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.03.20
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Orm.Providers;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/AsyncQueries/AsyncExtensionsTest.cs b/Orm/Xtensive.Orm.Tests/Storage/AsyncQueries/AsyncExtensionsTest.cs
index 4d94159fb..eb432d624 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/AsyncQueries/AsyncExtensionsTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/AsyncQueries/AsyncExtensionsTest.cs
@@ -2,9 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Linq;
-using System.Threading.Tasks;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Storage.AsyncQueries.Model;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/AsyncQueries/AsyncQueryBaseTest.cs b/Orm/Xtensive.Orm.Tests/Storage/AsyncQueries/AsyncQueryBaseTest.cs
index a843c1e01..a5a87e79f 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/AsyncQueries/AsyncQueryBaseTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/AsyncQueries/AsyncQueryBaseTest.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2019.09.12
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Storage.AsyncQueries.Model;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/AsyncQueries/Compiled/ClientProfileTest.cs b/Orm/Xtensive.Orm.Tests/Storage/AsyncQueries/Compiled/ClientProfileTest.cs
index 629108642..c046454ea 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/AsyncQueries/Compiled/ClientProfileTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/AsyncQueries/Compiled/ClientProfileTest.cs
@@ -4,10 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2019.09.12
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Threading.Tasks;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/AsyncQueries/Compiled/ServerProfileTest.cs b/Orm/Xtensive.Orm.Tests/Storage/AsyncQueries/Compiled/ServerProfileTest.cs
index 112d9b256..c45f3d099 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/AsyncQueries/Compiled/ServerProfileTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/AsyncQueries/Compiled/ServerProfileTest.cs
@@ -4,10 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2019.09.12
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Threading.Tasks;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/AsyncQueries/DelayedQueryClientProfileTest.cs b/Orm/Xtensive.Orm.Tests/Storage/AsyncQueries/DelayedQueryClientProfileTest.cs
index 2c8cd80cc..76faf3313 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/AsyncQueries/DelayedQueryClientProfileTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/AsyncQueries/DelayedQueryClientProfileTest.cs
@@ -4,9 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2019.09.12
 
-using System;
-using System.Linq;
-using System.Threading.Tasks;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Storage.AsyncQueries.Model;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/AsyncQueries/DelayedQueryServerProfileTest.cs b/Orm/Xtensive.Orm.Tests/Storage/AsyncQueries/DelayedQueryServerProfileTest.cs
index 81a218e7c..2f01be811 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/AsyncQueries/DelayedQueryServerProfileTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/AsyncQueries/DelayedQueryServerProfileTest.cs
@@ -4,9 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2019.09.12
 
-using System;
-using System.Linq;
-using System.Threading.Tasks;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Storage.AsyncQueries.Model;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/AsyncQueries/DelayedQueryTestBase.cs b/Orm/Xtensive.Orm.Tests/Storage/AsyncQueries/DelayedQueryTestBase.cs
index 132248aba..b729fb933 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/AsyncQueries/DelayedQueryTestBase.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/AsyncQueries/DelayedQueryTestBase.cs
@@ -4,10 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2019.09.12
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Threading.Tasks;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/AsyncQueries/ExecuteAsyncExtensionTest.cs b/Orm/Xtensive.Orm.Tests/Storage/AsyncQueries/ExecuteAsyncExtensionTest.cs
index 33787b34a..815a796c0 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/AsyncQueries/ExecuteAsyncExtensionTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/AsyncQueries/ExecuteAsyncExtensionTest.cs
@@ -4,10 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2019.09.12
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Threading.Tasks;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/AsyncQueries/Model.cs b/Orm/Xtensive.Orm.Tests/Storage/AsyncQueries/Model.cs
index 5e4c4fe93..ced0b9584 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/AsyncQueries/Model.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/AsyncQueries/Model.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2019.07.01
 
-using System;
 
 namespace Xtensive.Orm.Tests.Storage.AsyncQueries.Model
 {
diff --git a/Orm/Xtensive.Orm.Tests/Storage/AsyncQueries/PersistWithAsyncQueriesTest.cs b/Orm/Xtensive.Orm.Tests/Storage/AsyncQueries/PersistWithAsyncQueriesTest.cs
index f49da19c6..ffb0ee3f8 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/AsyncQueries/PersistWithAsyncQueriesTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/AsyncQueries/PersistWithAsyncQueriesTest.cs
@@ -4,9 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2019.07.12
 
-using System;
-using System.Linq;
-using System.Threading.Tasks;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/AsyncSession/AsyncSessionOpeningTest.cs b/Orm/Xtensive.Orm.Tests/Storage/AsyncSession/AsyncSessionOpeningTest.cs
index 288a901cd..acc833fe8 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/AsyncSession/AsyncSessionOpeningTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/AsyncSession/AsyncSessionOpeningTest.cs
@@ -4,10 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2019.07.12
 
-using System;
-using System.Linq;
-using System.Threading;
-using System.Threading.Tasks;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Providers;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/BatchingTest.cs b/Orm/Xtensive.Orm.Tests/Storage/BatchingTest.cs
index b5507c976..681ca40dc 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/BatchingTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/BatchingTest.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2010.02.18
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/ByteFieldStorageTest.cs b/Orm/Xtensive.Orm.Tests/Storage/ByteFieldStorageTest.cs
index 83099f912..f250c8c37 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/ByteFieldStorageTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/ByteFieldStorageTest.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2010.12.17
 
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/CascadeRemoveTest.cs b/Orm/Xtensive.Orm.Tests/Storage/CascadeRemoveTest.cs
index f3db11399..6769c24be 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/CascadeRemoveTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/CascadeRemoveTest.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2014.03.24
 
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Storage.CascadeRemoveTestModel;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/ChangedPersistOrderTest.cs b/Orm/Xtensive.Orm.Tests/Storage/ChangedPersistOrderTest.cs
index 678852261..c1447e8a9 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/ChangedPersistOrderTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/ChangedPersistOrderTest.cs
@@ -1,6 +1,3 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Text;
 using NUnit.Framework;
 using model = Xtensive.Orm.Tests.Storage.ChangedPersistOrderTestModel;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/ClientProfileReferentialIntegrityTest.cs b/Orm/Xtensive.Orm.Tests/Storage/ClientProfileReferentialIntegrityTest.cs
index ace862429..f6178d8f5 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/ClientProfileReferentialIntegrityTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/ClientProfileReferentialIntegrityTest.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2015.02.12
 
-using System.Collections.Generic;
-using System.Linq;
 using System.Reflection;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/ClientProfileSessionTest.cs b/Orm/Xtensive.Orm.Tests/Storage/ClientProfileSessionTest.cs
index 5d461bae7..964eab788 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/ClientProfileSessionTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/ClientProfileSessionTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2010.09.14
 
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/ClosureParametersCachingTest.cs b/Orm/Xtensive.Orm.Tests/Storage/ClosureParametersCachingTest.cs
index 5c53923e7..ffd315b9b 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/ClosureParametersCachingTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/ClosureParametersCachingTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2019.10.26
 
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/ClusteredIndexesTest.cs b/Orm/Xtensive.Orm.Tests/Storage/ClusteredIndexesTest.cs
index 620876bc6..1461d2354 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/ClusteredIndexesTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/ClusteredIndexesTest.cs
@@ -4,9 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2011.10.20
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Linq.Expressions;
 using NUnit.Framework;
 //using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/CmsTest.cs b/Orm/Xtensive.Orm.Tests/Storage/CmsTest.cs
index b40fd0c6b..b918b6937 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/CmsTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/CmsTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.12.16
 
-using System.Linq;
 using System.Reflection;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/CommandProcessing/BatchingCommandProcessorParametersManagement.cs b/Orm/Xtensive.Orm.Tests/Storage/CommandProcessing/BatchingCommandProcessorParametersManagement.cs
index f07dc0d37..029d84720 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/CommandProcessing/BatchingCommandProcessorParametersManagement.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/CommandProcessing/BatchingCommandProcessorParametersManagement.cs
@@ -2,10 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Threading.Tasks;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/CommandProcessing/BatchingOfVersionizedEntitiesTest.cs b/Orm/Xtensive.Orm.Tests/Storage/CommandProcessing/BatchingOfVersionizedEntitiesTest.cs
index 1715f87a9..5dd29a1f3 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/CommandProcessing/BatchingOfVersionizedEntitiesTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/CommandProcessing/BatchingOfVersionizedEntitiesTest.cs
@@ -2,9 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Linq;
-using System.Threading.Tasks;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/CommandProcessing/ParametersManagementModel.cs b/Orm/Xtensive.Orm.Tests/Storage/CommandProcessing/ParametersManagementModel.cs
index 7c416e3bc..483033698 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/CommandProcessing/ParametersManagementModel.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/CommandProcessing/ParametersManagementModel.cs
@@ -2,9 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Core;
 using Xtensive.Orm.Building;
 using Xtensive.Orm.Building.Definitions;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/CommandProcessing/SimpleCommandProcessorParametersManagement.cs b/Orm/Xtensive.Orm.Tests/Storage/CommandProcessing/SimpleCommandProcessorParametersManagement.cs
index c55f06c5b..cbae0f5b7 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/CommandProcessing/SimpleCommandProcessorParametersManagement.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/CommandProcessing/SimpleCommandProcessorParametersManagement.cs
@@ -4,9 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2019.04.14
 
-using System.Collections.Generic;
-using System.Linq;
-using System.Threading.Tasks;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/CompiledQueryTest.cs b/Orm/Xtensive.Orm.Tests/Storage/CompiledQueryTest.cs
index 61dfbab87..ee97acfe8 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/CompiledQueryTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/CompiledQueryTest.cs
@@ -4,13 +4,10 @@
 // Created by: Alexis Kochetov
 // Created:    2009.04.25
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Providers;
 using Xtensive.Orm.Tests.ObjectModel;
 using Xtensive.Orm.Tests.ObjectModel.ChinookDO;
-using System.Linq;
-using System.Threading.Tasks;
 
 namespace Xtensive.Orm.Tests.Storage
 {
diff --git a/Orm/Xtensive.Orm.Tests/Storage/ConnectionAccessorTest.cs b/Orm/Xtensive.Orm.Tests/Storage/ConnectionAccessorTest.cs
index 41d42876b..25b9b34ee 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/ConnectionAccessorTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/ConnectionAccessorTest.cs
@@ -2,17 +2,13 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Collections.Generic;
 using System.Diagnostics;
-using System.Linq;
 using System.Text;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Orm.Providers;
 using Xtensive.Sql;
 using Xtensive.Orm.Tests.Storage.ConnectionAccessorsModel;
-using System.Threading.Tasks;
 
 namespace Xtensive.Orm.Tests.Storage.ConnectionAccessorsModel
 {
diff --git a/Orm/Xtensive.Orm.Tests/Storage/CoreServicesTest.cs b/Orm/Xtensive.Orm.Tests/Storage/CoreServicesTest.cs
index 3faa88ec4..c728f37e0 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/CoreServicesTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/CoreServicesTest.cs
@@ -4,8 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2008.11.03
 
-using System;
-using System.Linq;
 using System.Reflection;
 using NUnit.Framework;
 using Xtensive.Orm.Services;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/CustomCollationTest.cs b/Orm/Xtensive.Orm.Tests/Storage/CustomCollationTest.cs
index 6dfd4a27c..1b65c5e7f 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/CustomCollationTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/CustomCollationTest.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.06.05
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Storage.CustomCollationTestModel;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/CustomEntitySetTest.cs b/Orm/Xtensive.Orm.Tests/Storage/CustomEntitySetTest.cs
index 7487777e4..7821a545f 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/CustomEntitySetTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/CustomEntitySetTest.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2008.11.07
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Model;
 using Xtensive.Orm.Tests.Storage.CustomEntitySetModel;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/CustomMetadataUpgrade.cs b/Orm/Xtensive.Orm.Tests/Storage/CustomMetadataUpgrade.cs
index b105da258..65b898cf8 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/CustomMetadataUpgrade.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/CustomMetadataUpgrade.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.05.29
 
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Metadata;
 
diff --git a/Orm/Xtensive.Orm.Tests/Storage/DataErrorInfo.cs b/Orm/Xtensive.Orm.Tests/Storage/DataErrorInfo.cs
index 9678e5f01..6f5a4acf0 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/DataErrorInfo.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/DataErrorInfo.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Kofman
 // Created:    2009.09.17
 
-using System;
 using System.ComponentModel;
 using NUnit.Framework;
 using Xtensive.Orm.Validation;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/DateTimeStoragePrecisionTest.cs b/Orm/Xtensive.Orm.Tests/Storage/DateTimeStoragePrecisionTest.cs
index dfbc14fc6..5589c4a8c 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/DateTimeStoragePrecisionTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/DateTimeStoragePrecisionTest.cs
@@ -2,8 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Storage.DateTimeStoragePrecisionTestModel;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/DirectSqlTest.cs b/Orm/Xtensive.Orm.Tests/Storage/DirectSqlTest.cs
index a950aef90..e62fc3eee 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/DirectSqlTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/DirectSqlTest.cs
@@ -4,9 +4,7 @@
 // Created by: Alexis Kochetov
 // Created:    2010.01.29
 
-using System;
 using System.Data.Common;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Orm.Tests;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/DisableIndexOnReferenceFieldTest.cs b/Orm/Xtensive.Orm.Tests/Storage/DisableIndexOnReferenceFieldTest.cs
index eaa54e3a5..9ddd4dc6f 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/DisableIndexOnReferenceFieldTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/DisableIndexOnReferenceFieldTest.cs
@@ -4,9 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2011.10.05
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Model;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/DisableSaveChangesTest.cs b/Orm/Xtensive.Orm.Tests/Storage/DisableSaveChangesTest.cs
index 8c6fa7b6b..90fd37ca5 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/DisableSaveChangesTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/DisableSaveChangesTest.cs
@@ -4,10 +4,7 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.12.11
 
-using System.Collections.Generic;
-using System.Linq;
 using NUnit.Framework;
-using System;
 using Xtensive.Orm.Tests;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Storage.DisableSaveChangesTestModel;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/DisableValidationAndImplicitConstraintsTest.cs b/Orm/Xtensive.Orm.Tests/Storage/DisableValidationAndImplicitConstraintsTest.cs
index a3dada4d9..7bb1333fc 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/DisableValidationAndImplicitConstraintsTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/DisableValidationAndImplicitConstraintsTest.cs
@@ -1,4 +1,3 @@
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Storage.DisableValidationAndImplicitConstraintsTestModel;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/DuplicateIndexTest.cs b/Orm/Xtensive.Orm.Tests/Storage/DuplicateIndexTest.cs
index d78d81a8c..2107bb6b0 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/DuplicateIndexTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/DuplicateIndexTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2010.02.04
 
-using System;
 using System.Diagnostics;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/EntityChangeRegistryTest.cs b/Orm/Xtensive.Orm.Tests/Storage/EntityChangeRegistryTest.cs
index 08f3ccade..77dac50c3 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/EntityChangeRegistryTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/EntityChangeRegistryTest.cs
@@ -5,9 +5,6 @@
 // Created:    2020.02.14
 
 using NUnit.Framework;
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Linq.Expressions;
 using System.Text;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/EntitySetRollbackTest.cs b/Orm/Xtensive.Orm.Tests/Storage/EntitySetRollbackTest.cs
index e0f23ca74..8eae5c817 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/EntitySetRollbackTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/EntitySetRollbackTest.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2014.03.03
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Storage.EntitySetRollbackTestModel;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/EntitySetTest.cs b/Orm/Xtensive.Orm.Tests/Storage/EntitySetTest.cs
index 64baf196c..51d19a90e 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/EntitySetTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/EntitySetTest.cs
@@ -4,9 +4,6 @@
 // Created by: Elena Vakhtina
 // Created:    2009.03.11
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Reflection;
 using NUnit.Framework;
 using Xtensive.Collections;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/ExecuteDelayedForIOrderedQueryableQuery.cs b/Orm/Xtensive.Orm.Tests/Storage/ExecuteDelayedForIOrderedQueryableQuery.cs
index f05d0cfd9..e1a3b7d66 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/ExecuteDelayedForIOrderedQueryableQuery.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/ExecuteDelayedForIOrderedQueryableQuery.cs
@@ -4,9 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2014.06.23
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Linq.ExecuteDelayedForIOrderedQueryableQueryModel;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/FailedQueryAndDbCommandNotificationsTest.cs b/Orm/Xtensive.Orm.Tests/Storage/FailedQueryAndDbCommandNotificationsTest.cs
index ec1488a88..4c551e2d6 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/FailedQueryAndDbCommandNotificationsTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/FailedQueryAndDbCommandNotificationsTest.cs
@@ -4,8 +4,6 @@
 // Created by: Julian Mamokin
 // Created:    2017.02.08
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Storage.FailedQueryAndDbCommandNotificationsTestModel;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/FieldDefaultValueTest.cs b/Orm/Xtensive.Orm.Tests/Storage/FieldDefaultValueTest.cs
index e6681ffab..aefdb9599 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/FieldDefaultValueTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/FieldDefaultValueTest.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2008.09.19
 
-using System;
 using System.Reflection;
 using NUnit.Framework;
 using Xtensive.Orm.Providers;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/FieldSqlDefaultTest.cs b/Orm/Xtensive.Orm.Tests/Storage/FieldSqlDefaultTest.cs
index a05604b1a..2931bf0f3 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/FieldSqlDefaultTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/FieldSqlDefaultTest.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2014.02.26
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Building;
 using Xtensive.Orm.Building.Definitions;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/ForceServerVersion.cs b/Orm/Xtensive.Orm.Tests/Storage/ForceServerVersion.cs
index 0a275e8c0..4e1a9bee6 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/ForceServerVersion.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/ForceServerVersion.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.03.06
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Services;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/ForeignKeyTest.cs b/Orm/Xtensive.Orm.Tests/Storage/ForeignKeyTest.cs
index 020016611..7cb801dba 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/ForeignKeyTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/ForeignKeyTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2009.03.11
 
-using System;
 using NUnit.Framework;
 using Xtensive.IoC;
 using Xtensive.Tuples;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/FutureTest.cs b/Orm/Xtensive.Orm.Tests/Storage/FutureTest.cs
index 620d0cc3a..c34031548 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/FutureTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/FutureTest.cs
@@ -4,11 +4,6 @@
 // Created by: Alexander Nikolaev
 // Created:    2009.08.20
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Threading;
-using System.Threading.Tasks;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Orm.Internals;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/GeneralBehaviorTest.cs b/Orm/Xtensive.Orm.Tests/Storage/GeneralBehaviorTest.cs
index 6732b7de7..8ac1e0c99 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/GeneralBehaviorTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/GeneralBehaviorTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alexander Nikolaev
 // Created:    2010.02.17
 
-using System;
 using System.Diagnostics;
 using NUnit.Framework;
 using Xtensive.Orm.Tests.Storage.GeneralBehaviorTestModel;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/GenericTest.cs b/Orm/Xtensive.Orm.Tests/Storage/GenericTest.cs
index b39f6b840..0f5bf7818 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/GenericTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/GenericTest.cs
@@ -4,8 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2010.03.12
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/IgnoreRulesConfigureTest.cs b/Orm/Xtensive.Orm.Tests/Storage/IgnoreRulesConfigureTest.cs
index 15dd6d331..e11d5e9ce 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/IgnoreRulesConfigureTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/IgnoreRulesConfigureTest.cs
@@ -2,7 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 
diff --git a/Orm/Xtensive.Orm.Tests/Storage/IgnoreRulesHandlerTest.cs b/Orm/Xtensive.Orm.Tests/Storage/IgnoreRulesHandlerTest.cs
index 572309892..4cf1a2d3f 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/IgnoreRulesHandlerTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/IgnoreRulesHandlerTest.cs
@@ -2,7 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Providers;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/IgnoreRulesValidateTest.cs b/Orm/Xtensive.Orm.Tests/Storage/IgnoreRulesValidateTest.cs
index 144d6cf2c..be4422d97 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/IgnoreRulesValidateTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/IgnoreRulesValidateTest.cs
@@ -4,9 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2013.08.16
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Orm.Building.Definitions;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/IntermediateQueryTest.cs b/Orm/Xtensive.Orm.Tests/Storage/IntermediateQueryTest.cs
index 00be2cc4a..c8d2e5284 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/IntermediateQueryTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/IntermediateQueryTest.cs
@@ -4,8 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2010.11.17
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Internals;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/IoC/ProxyContainerBase.cs b/Orm/Xtensive.Orm.Tests/Storage/IoC/ProxyContainerBase.cs
index 55eca7915..b170ba881 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/IoC/ProxyContainerBase.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/IoC/ProxyContainerBase.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2010.02.11
 
-using System;
-using System.Collections.Generic;
 using Xtensive.IoC;
 
 namespace Xtensive.Orm.Tests.Storage.IoC
diff --git a/Orm/Xtensive.Orm.Tests/Storage/IoC/QueryFormatterServiceTest.cs b/Orm/Xtensive.Orm.Tests/Storage/IoC/QueryFormatterServiceTest.cs
index eb703b916..7a5dcad49 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/IoC/QueryFormatterServiceTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/IoC/QueryFormatterServiceTest.cs
@@ -4,9 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2011.03.02
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.IoC;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/IoC/ServiceTestBase.cs b/Orm/Xtensive.Orm.Tests/Storage/IoC/ServiceTestBase.cs
index a44216408..5d04a07f4 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/IoC/ServiceTestBase.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/IoC/ServiceTestBase.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2009.12.16
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Storage.IoC.Model;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/KeysTest.cs b/Orm/Xtensive.Orm.Tests/Storage/KeysTest.cs
index 7c1c3de0d..69fa64dac 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/KeysTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/KeysTest.cs
@@ -4,7 +4,6 @@
 // Created by: 
 // Created:    2008.09.17
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Storage.Keys;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/LazyLoadTest.cs b/Orm/Xtensive.Orm.Tests/Storage/LazyLoadTest.cs
index f95e7c90b..087c6a4b2 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/LazyLoadTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/LazyLoadTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2008.06.26
 
-using System;
 using System.Reflection;
 using NUnit.Framework;
 using Xtensive.Tuples;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/LegacyDb/AnimalDbBaseTest.cs b/Orm/Xtensive.Orm.Tests/Storage/LegacyDb/AnimalDbBaseTest.cs
index 04d26ccd2..960c9408c 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/LegacyDb/AnimalDbBaseTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/LegacyDb/AnimalDbBaseTest.cs
@@ -4,8 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2009.11.26
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Model;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/LegacyDb/ContainerItemTest.cs b/Orm/Xtensive.Orm.Tests/Storage/LegacyDb/ContainerItemTest.cs
index e23e91378..f6e19b440 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/LegacyDb/ContainerItemTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/LegacyDb/ContainerItemTest.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2009.11.26
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Storage.LegacyDb.ContainerItemModel;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/LegacyDb/CrazyColumns2005Test.cs b/Orm/Xtensive.Orm.Tests/Storage/LegacyDb/CrazyColumns2005Test.cs
index 439845b22..8d2c7a58e 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/LegacyDb/CrazyColumns2005Test.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/LegacyDb/CrazyColumns2005Test.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2010.03.03
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Storage.LegacyDb.CrazyColumns2005TestModel;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/LegacyDb/CrazyColumns2008Test.cs b/Orm/Xtensive.Orm.Tests/Storage/LegacyDb/CrazyColumns2008Test.cs
index ecb1e1770..c5238cb7e 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/LegacyDb/CrazyColumns2008Test.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/LegacyDb/CrazyColumns2008Test.cs
@@ -4,8 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2009.12.02
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Storage.LegacyDb.CrazyColumns2008TestModel;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/ManyToManyValidationTest.cs b/Orm/Xtensive.Orm.Tests/Storage/ManyToManyValidationTest.cs
index 702f7e5f4..645fa1644 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/ManyToManyValidationTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/ManyToManyValidationTest.cs
@@ -4,8 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2010.11.10
 
-using System;
-using System.Linq;
 using System.Runtime.Serialization;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/MemoryProviderTest.cs b/Orm/Xtensive.Orm.Tests/Storage/MemoryProviderTest.cs
index 672c4a00d..c5a6e6605 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/MemoryProviderTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/MemoryProviderTest.cs
@@ -4,9 +4,7 @@
 // Created by: Denis Krjuchkov
 // Created:    2013.02.14
 
-using System;
 using System.Data;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Orm.Providers;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/Modules/Assembly0.cs b/Orm/Xtensive.Orm.Tests/Storage/Modules/Assembly0.cs
index 5e43cc8c7..48026a7d0 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/Modules/Assembly0.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/Modules/Assembly0.cs
@@ -4,7 +4,6 @@
 // Created by: Alexander Nikolaev
 // Created:    2009.07.03
 
-using System;
 using System.Diagnostics;
 using Xtensive.Orm;
 
diff --git a/Orm/Xtensive.Orm.Tests/Storage/Modules/Assembly1.cs b/Orm/Xtensive.Orm.Tests/Storage/Modules/Assembly1.cs
index 1e456dae4..f5d2c2ae7 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/Modules/Assembly1.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/Modules/Assembly1.cs
@@ -4,9 +4,7 @@
 // Created by: Alexander Nikolaev
 // Created:    2009.07.03
 
-using System;
 using System.Diagnostics;
-using System.Linq;
 using Xtensive.Orm;
 using Xtensive.Orm.Building;
 using Xtensive.Orm.Building.Definitions;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/Modules/Assembly2.cs b/Orm/Xtensive.Orm.Tests/Storage/Modules/Assembly2.cs
index 8fe613592..0c49df0f4 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/Modules/Assembly2.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/Modules/Assembly2.cs
@@ -4,9 +4,7 @@
 // Created by: Alexander Nikolaev
 // Created:    2009.07.03
 
-using System;
 using System.Diagnostics;
-using System.Linq;
 using System.Reflection;
 using Xtensive.Orm;
 using Xtensive.Orm.Building;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/Modules/ModulesRegistrationTest.cs b/Orm/Xtensive.Orm.Tests/Storage/Modules/ModulesRegistrationTest.cs
index 5b7073d28..4b4bd171d 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/Modules/ModulesRegistrationTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/Modules/ModulesRegistrationTest.cs
@@ -4,10 +4,8 @@
 // Created by: Alexander Nikolaev
 // Created:    2009.07.03
 
-using System;
 using System.CodeDom.Compiler;
 using System.IO;
-using System.Linq;
 using System.Reflection;
 using NUnit.Framework;
 
diff --git a/Orm/Xtensive.Orm.Tests/Storage/Multimapping/CaseSensitiveSchemasTest.cs b/Orm/Xtensive.Orm.Tests/Storage/Multimapping/CaseSensitiveSchemasTest.cs
index 8234eb3e7..8e6599254 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/Multimapping/CaseSensitiveSchemasTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/Multimapping/CaseSensitiveSchemasTest.cs
@@ -2,7 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using M = Xtensive.Orm.Tests.Storage.Multimapping.CaseSensitiveSchemasTestModel;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/Multimapping/CrossDatabaseTableMoveTest.cs b/Orm/Xtensive.Orm.Tests/Storage/Multimapping/CrossDatabaseTableMoveTest.cs
index 2399b8a2a..0e2d105d4 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/Multimapping/CrossDatabaseTableMoveTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/Multimapping/CrossDatabaseTableMoveTest.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.03.16
 
-using System.Linq;
 using NUnit.Framework;
 using V1 = Xtensive.Orm.Tests.Storage.Multimapping.CrossRenameModel.Version1;
 using V2 = Xtensive.Orm.Tests.Storage.Multimapping.CrossRenameModel.Version2;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/Multimapping/CrossRenameModel/Version2/UpgradeHandler.cs b/Orm/Xtensive.Orm.Tests/Storage/Multimapping/CrossRenameModel/Version2/UpgradeHandler.cs
index 99f47b4ec..350f7e962 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/Multimapping/CrossRenameModel/Version2/UpgradeHandler.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/Multimapping/CrossRenameModel/Version2/UpgradeHandler.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.03.16
 
-using System.Collections.Generic;
 using Xtensive.Orm.Upgrade;
 
 namespace Xtensive.Orm.Tests.Storage.Multimapping.CrossRenameModel.Version2
diff --git a/Orm/Xtensive.Orm.Tests/Storage/Multimapping/CrossSchemaTableMoveTest.cs b/Orm/Xtensive.Orm.Tests/Storage/Multimapping/CrossSchemaTableMoveTest.cs
index 35a1287db..f23ab9773 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/Multimapping/CrossSchemaTableMoveTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/Multimapping/CrossSchemaTableMoveTest.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.03.16
 
-using System.Linq;
 using NUnit.Framework;
 using V1 = Xtensive.Orm.Tests.Storage.Multimapping.CrossRenameModel.Version1;
 using V2 = Xtensive.Orm.Tests.Storage.Multimapping.CrossRenameModel.Version2;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/Multimapping/CycleReferencesDetectionTest.cs b/Orm/Xtensive.Orm.Tests/Storage/Multimapping/CycleReferencesDetectionTest.cs
index 6db8a9f81..6131044eb 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/Multimapping/CycleReferencesDetectionTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/Multimapping/CycleReferencesDetectionTest.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.02.14
 
-using System;
-using System.Collections.Generic;
 using NUnit.Framework;
 using Xtensive.Orm.Tests.Storage.Multimapping.CycleReferencesDetectionModel.Namespace1;
 using Xtensive.Orm.Tests.Storage.Multimapping.CycleReferencesDetectionModel.Namespace2;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/Multimapping/InterfaceAndAssociationMappingTest.cs b/Orm/Xtensive.Orm.Tests/Storage/Multimapping/InterfaceAndAssociationMappingTest.cs
index 84d0859d1..74dec7515 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/Multimapping/InterfaceAndAssociationMappingTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/Multimapping/InterfaceAndAssociationMappingTest.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.11.14
 
-using System;
-using System.Collections.Generic;
 using NUnit.Framework;
 using Xtensive.Orm.Tests.Storage.Multimapping.InterfaceAndAssociationMappingTestModel.Entities;
 using Xtensive.Orm.Tests.Storage.Multimapping.InterfaceAndAssociationMappingTestModel.Interfaces;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/Multinode/ConnectionOverrideTest.cs b/Orm/Xtensive.Orm.Tests/Storage/Multinode/ConnectionOverrideTest.cs
index b6db1e359..f878233b7 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/Multinode/ConnectionOverrideTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/Multinode/ConnectionOverrideTest.cs
@@ -2,8 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Collections.Generic;
 using System.Text;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/Multinode/DynamicTypeIdTest.cs b/Orm/Xtensive.Orm.Tests/Storage/Multinode/DynamicTypeIdTest.cs
index 4053ed9d1..cf6e6e0eb 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/Multinode/DynamicTypeIdTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/Multinode/DynamicTypeIdTest.cs
@@ -4,10 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2014.03.26
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Threading.Tasks;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Providers;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/Multinode/InitializationSqlOverrideTest.cs b/Orm/Xtensive.Orm.Tests/Storage/Multinode/InitializationSqlOverrideTest.cs
index 313cab6ff..3bf291a79 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/Multinode/InitializationSqlOverrideTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/Multinode/InitializationSqlOverrideTest.cs
@@ -2,8 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Collections.Generic;
 using System.Text;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/Multinode/QueryCachingTest.cs b/Orm/Xtensive.Orm.Tests/Storage/Multinode/QueryCachingTest.cs
index 8a03700bd..cec50b4b2 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/Multinode/QueryCachingTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/Multinode/QueryCachingTest.cs
@@ -5,9 +5,6 @@
 // Created:    2019.01.28
 
 using NUnit.Framework;
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Collections;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Storage.Multinode.QueryCachingTestModel;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/Multinode/StaleQueryCacheForReAddedNodes.cs b/Orm/Xtensive.Orm.Tests/Storage/Multinode/StaleQueryCacheForReAddedNodes.cs
index 9b1a14a81..73f827ac7 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/Multinode/StaleQueryCacheForReAddedNodes.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/Multinode/StaleQueryCacheForReAddedNodes.cs
@@ -2,9 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Text;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/Multinode/StandardMultinodeTest.cs b/Orm/Xtensive.Orm.Tests/Storage/Multinode/StandardMultinodeTest.cs
index 69b451b89..fd2545ba3 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/Multinode/StandardMultinodeTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/Multinode/StandardMultinodeTest.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2014.03.26
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Storage.Keys;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/Multinode/StorageNodeManagerTest.cs b/Orm/Xtensive.Orm.Tests/Storage/Multinode/StorageNodeManagerTest.cs
index 1d9617ac4..8e42a6871 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/Multinode/StorageNodeManagerTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/Multinode/StorageNodeManagerTest.cs
@@ -2,8 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Collections.Generic;
 using System.Text;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/Multinode/TypeIdAllocationTest.cs b/Orm/Xtensive.Orm.Tests/Storage/Multinode/TypeIdAllocationTest.cs
index c2e0da11a..1f77e70bb 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/Multinode/TypeIdAllocationTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/Multinode/TypeIdAllocationTest.cs
@@ -4,10 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2015.12.01
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Threading.Tasks;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/NestedTransactionsTest.cs b/Orm/Xtensive.Orm.Tests/Storage/NestedTransactionsTest.cs
index 520ec616d..b17a12c3d 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/NestedTransactionsTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/NestedTransactionsTest.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.11.26
 
-using System.Collections.Generic;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Orm.Providers;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/NewProfilesTest.cs b/Orm/Xtensive.Orm.Tests/Storage/NewProfilesTest.cs
index f09a43aca..2297685cb 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/NewProfilesTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/NewProfilesTest.cs
@@ -4,10 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2014.04.14
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Threading;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Internals;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/NonPersistentCompositeObjectTest.cs b/Orm/Xtensive.Orm.Tests/Storage/NonPersistentCompositeObjectTest.cs
index 4a490baaa..08cd0537c 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/NonPersistentCompositeObjectTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/NonPersistentCompositeObjectTest.cs
@@ -4,8 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2010.10.13
 
-using System;
-using System.Linq;
 using System.Linq.Expressions;
 using NUnit.Framework;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/NonTransactionalEntityAccess.cs b/Orm/Xtensive.Orm.Tests/Storage/NonTransactionalEntityAccess.cs
index 975ec65ff..67c8eeb49 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/NonTransactionalEntityAccess.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/NonTransactionalEntityAccess.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2014.01.30
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Storage.TransactionsTestModel;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/NotifyPropertyChangedTest.cs b/Orm/Xtensive.Orm.Tests/Storage/NotifyPropertyChangedTest.cs
index f5e5a6a6a..ad8aae562 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/NotifyPropertyChangedTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/NotifyPropertyChangedTest.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2008.10.02
 
-using System;
 using System.ComponentModel;
 using System.Reflection;
 using NUnit.Framework;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/NotifyXxxTest.cs b/Orm/Xtensive.Orm.Tests/Storage/NotifyXxxTest.cs
index 4baee1087..819ac67ae 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/NotifyXxxTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/NotifyXxxTest.cs
@@ -4,10 +4,8 @@
 // Created by: Alex Yakunin
 // Created:    2010.06.24
 
-using System;
 using System.Collections.Specialized;
 using System.ComponentModel;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/OnRemovingTest.cs b/Orm/Xtensive.Orm.Tests/Storage/OnRemovingTest.cs
index 28194652c..a25dae735 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/OnRemovingTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/OnRemovingTest.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2009.12.21
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Storage.OnRemovingTestModel;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/OperationOrderTest.cs b/Orm/Xtensive.Orm.Tests/Storage/OperationOrderTest.cs
index 5c5e97146..a76ae4148 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/OperationOrderTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/OperationOrderTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2010.08.12
 
-using System;
 using System.Diagnostics;
 using NUnit.Framework;
 
@@ -13,7 +12,6 @@
 using Xtensive.Reflection;
 using Xtensive.Orm.Operations;
 using Xtensive.Core;
-using System.Linq;
 
 namespace Xtensive.Orm.Tests.Storage.OperationOrderTest
 {
diff --git a/Orm/Xtensive.Orm.Tests/Storage/OverrideConnectionInfoTest.cs b/Orm/Xtensive.Orm.Tests/Storage/OverrideConnectionInfoTest.cs
index e81127f14..bbe68a82f 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/OverrideConnectionInfoTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/OverrideConnectionInfoTest.cs
@@ -1,4 +1,4 @@
-// Copyright (C) 2014 Xtensive LLC.
+// Copyright (C) 2014 Xtensive LLC.
 // All rights reserved.
 // For conditions of distribution and use, see license.
 // Created by: Denis Krjuchkov
@@ -6,6 +6,7 @@
 
 using NUnit.Framework;
 using Xtensive.Orm.Metadata;
+using Type = Xtensive.Orm.Metadata.Type;
 
 namespace Xtensive.Orm.Tests.Storage
 {
diff --git a/Orm/Xtensive.Orm.Tests/Storage/OverrideMetadata.cs b/Orm/Xtensive.Orm.Tests/Storage/OverrideMetadata.cs
index 27f71d41b..5052b78b8 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/OverrideMetadata.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/OverrideMetadata.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2011.10.28
 
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/PartialIndexTest.cs b/Orm/Xtensive.Orm.Tests/Storage/PartialIndexTest.cs
index 2a8bf8cbd..82f544656 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/PartialIndexTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/PartialIndexTest.cs
@@ -4,9 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2011.10.06
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Linq.Expressions;
 using NUnit.Framework;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/Performance/CrudModel/NonPairedSimplestContainerItem.cs b/Orm/Xtensive.Orm.Tests/Storage/Performance/CrudModel/NonPairedSimplestContainerItem.cs
index e1f06a2f5..c8c9f10c0 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/Performance/CrudModel/NonPairedSimplestContainerItem.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/Performance/CrudModel/NonPairedSimplestContainerItem.cs
@@ -4,7 +4,6 @@
 // Created by: Alexander Nikolaev
 // Created:    2009.08.04
 
-using System;
 
 namespace Xtensive.Orm.Tests.Storage.Performance.CrudModel
 {
diff --git a/Orm/Xtensive.Orm.Tests/Storage/Performance/CrudModel/PairedSimplestContainerItem.cs b/Orm/Xtensive.Orm.Tests/Storage/Performance/CrudModel/PairedSimplestContainerItem.cs
index b5e1dcd15..98a5e1442 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/Performance/CrudModel/PairedSimplestContainerItem.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/Performance/CrudModel/PairedSimplestContainerItem.cs
@@ -4,7 +4,6 @@
 // Created by: Alexander Nikolaev
 // Created:    2009.08.04
 
-using System;
 
 namespace Xtensive.Orm.Tests.Storage.Performance.CrudModel
 {
diff --git a/Orm/Xtensive.Orm.Tests/Storage/Performance/CrudModel/Simplest.cs b/Orm/Xtensive.Orm.Tests/Storage/Performance/CrudModel/Simplest.cs
index a1fc17419..7cddec12f 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/Performance/CrudModel/Simplest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/Performance/CrudModel/Simplest.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.09.23
 
-using System;
 using Xtensive.Tuples;
 using Tuple = Xtensive.Tuples.Tuple;
 
diff --git a/Orm/Xtensive.Orm.Tests/Storage/Performance/CrudModel/SimplestContainer.cs b/Orm/Xtensive.Orm.Tests/Storage/Performance/CrudModel/SimplestContainer.cs
index 5569524b3..badaf0951 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/Performance/CrudModel/SimplestContainer.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/Performance/CrudModel/SimplestContainer.cs
@@ -4,7 +4,6 @@
 // Created by: Alexander Nikolaev
 // Created:    2009.08.03
 
-using System;
 
 namespace Xtensive.Orm.Tests.Storage.Performance.CrudModel
 {
diff --git a/Orm/Xtensive.Orm.Tests/Storage/Performance/DoCrudTest.cs b/Orm/Xtensive.Orm.Tests/Storage/Performance/DoCrudTest.cs
index 8ca0503f8..63421c693 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/Performance/DoCrudTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/Performance/DoCrudTest.cs
@@ -2,8 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System.Collections.Generic;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/Performance/SqlClientCrudTest.cs b/Orm/Xtensive.Orm.Tests/Storage/Performance/SqlClientCrudTest.cs
index 77b1a85ee..5d9c7d04c 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/Performance/SqlClientCrudTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/Performance/SqlClientCrudTest.cs
@@ -4,7 +4,6 @@
 // Created by: Elena Vakhtina
 // Created:    2008.09.19
 
-using System.Collections.Generic;
 using Microsoft.Data.SqlClient;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/PersistTest.cs b/Orm/Xtensive.Orm.Tests/Storage/PersistTest.cs
index 9ef3613c2..3de16628f 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/PersistTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/PersistTest.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.06.01
 
-using System;
 using System.Diagnostics;
 using NUnit.Framework;
 using Xtensive.Orm.Tests.ObjectModel.ChinookDO;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/PostgreSqlSpatialTest.cs b/Orm/Xtensive.Orm.Tests/Storage/PostgreSqlSpatialTest.cs
index 2227a7f4e..a8d2b34dd 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/PostgreSqlSpatialTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/PostgreSqlSpatialTest.cs
@@ -4,8 +4,6 @@
 // Created by: Alena Mikshina
 // Created:    2014.04.09
 
-using System;
-using System.Linq;
 using NpgsqlTypes;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/Prefetch/Model.cs b/Orm/Xtensive.Orm.Tests/Storage/Prefetch/Model.cs
index 3a5e6e366..630c09223 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/Prefetch/Model.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/Prefetch/Model.cs
@@ -4,10 +4,7 @@
 // Created by: Alexander Nikolaev
 // Created:    2009.10.10
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
-using System.Linq;
 
 namespace Xtensive.Orm.Tests.Storage.Prefetch.Model
 {
diff --git a/Orm/Xtensive.Orm.Tests/Storage/Prefetch/PrefetchDelayedElementsTest.cs b/Orm/Xtensive.Orm.Tests/Storage/Prefetch/PrefetchDelayedElementsTest.cs
index b93aaa48e..db156eea5 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/Prefetch/PrefetchDelayedElementsTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/Prefetch/PrefetchDelayedElementsTest.cs
@@ -4,9 +4,6 @@
 // Created by: Alexander Nikolaev
 // Created:    2009.10.07
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Tuples;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/Prefetch/PrefetchManagerAdvancedTest.cs b/Orm/Xtensive.Orm.Tests/Storage/Prefetch/PrefetchManagerAdvancedTest.cs
index 13ae8c997..2ab975b21 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/Prefetch/PrefetchManagerAdvancedTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/Prefetch/PrefetchManagerAdvancedTest.cs
@@ -4,10 +4,7 @@
 // Created by: Alexander Nikolaev
 // Created:    2009.10.26
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
-using System.Linq;
 using System.Reflection;
 using NUnit.Framework;
 using Xtensive.Collections;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/Prefetch/PrefetchManagerBasicTest.cs b/Orm/Xtensive.Orm.Tests/Storage/Prefetch/PrefetchManagerBasicTest.cs
index ca375845f..4732ee63a 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/Prefetch/PrefetchManagerBasicTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/Prefetch/PrefetchManagerBasicTest.cs
@@ -4,11 +4,7 @@
 // Created by: Alexander Nikolaev
 // Created:    2009.09.07
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Runtime.CompilerServices;
-using System.Threading;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Collections;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/Prefetch/PrefetchManagerTestBase.cs b/Orm/Xtensive.Orm.Tests/Storage/Prefetch/PrefetchManagerTestBase.cs
index 428918644..d03839a3d 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/Prefetch/PrefetchManagerTestBase.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/Prefetch/PrefetchManagerTestBase.cs
@@ -4,9 +4,6 @@
 // Created by: Alexander Nikolaev
 // Created:    2009.10.26
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Reflection;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/Prefetch/PrefetchTest.cs b/Orm/Xtensive.Orm.Tests/Storage/Prefetch/PrefetchTest.cs
index ccb73d941..3ce2b51a3 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/Prefetch/PrefetchTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/Prefetch/PrefetchTest.cs
@@ -4,10 +4,6 @@
 // Created by: Alexander Nikolaev
 // Created:    2009.09.30
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Threading.Tasks;
 using NUnit.Framework;
 using Xtensive.Collections;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/Prefetch/PrefetchTestHelper.cs b/Orm/Xtensive.Orm.Tests/Storage/Prefetch/PrefetchTestHelper.cs
index d573a7368..ea126d743 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/Prefetch/PrefetchTestHelper.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/Prefetch/PrefetchTestHelper.cs
@@ -4,9 +4,6 @@
 // Created by: Alexander Nikolaev
 // Created:    2009.10.10
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Tuples;
 using Tuple = Xtensive.Tuples.Tuple;
 using Xtensive.Orm.Internals;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/Prefetch/PrefetchWithSmallCacheTest.cs b/Orm/Xtensive.Orm.Tests/Storage/Prefetch/PrefetchWithSmallCacheTest.cs
index f866abf4e..484491fcc 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/Prefetch/PrefetchWithSmallCacheTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/Prefetch/PrefetchWithSmallCacheTest.cs
@@ -4,9 +4,6 @@
 // Created by: Alexander Nikolaev
 // Created:    2009.10.08
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/Providers/Sql/BooleanHandlingTest.cs b/Orm/Xtensive.Orm.Tests/Storage/Providers/Sql/BooleanHandlingTest.cs
index aa572d1e1..5d6e73c44 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/Providers/Sql/BooleanHandlingTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/Providers/Sql/BooleanHandlingTest.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.03.20
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/Providers/Sql/CharSupportTest.cs b/Orm/Xtensive.Orm.Tests/Storage/Providers/Sql/CharSupportTest.cs
index 9103bbf4c..5d9486f75 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/Providers/Sql/CharSupportTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/Providers/Sql/CharSupportTest.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.04.20
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/Providers/Sql/CustomConnectionInfoTest.cs b/Orm/Xtensive.Orm.Tests/Storage/Providers/Sql/CustomConnectionInfoTest.cs
index 93076ed50..58c8b597a 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/Providers/Sql/CustomConnectionInfoTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/Providers/Sql/CustomConnectionInfoTest.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2010.06.10
 
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Metadata;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/Providers/Sql/NullValuesTest.cs b/Orm/Xtensive.Orm.Tests/Storage/Providers/Sql/NullValuesTest.cs
index a7c8c7fd7..379ca89a8 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/Providers/Sql/NullValuesTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/Providers/Sql/NullValuesTest.cs
@@ -5,8 +5,6 @@
 // Created:    2009.04.25
 
 using NUnit.Framework;
-using System.Collections.Generic;
-using System.Linq;
 
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Providers;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/Providers/Sql/RoundingTest.cs b/Orm/Xtensive.Orm.Tests/Storage/Providers/Sql/RoundingTest.cs
index fdac9a83a..f0cd0565d 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/Providers/Sql/RoundingTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/Providers/Sql/RoundingTest.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.06.09
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/Providers/Sql/StringOperationsTest.cs b/Orm/Xtensive.Orm.Tests/Storage/Providers/Sql/StringOperationsTest.cs
index 633321395..b53700224 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/Providers/Sql/StringOperationsTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/Providers/Sql/StringOperationsTest.cs
@@ -5,7 +5,6 @@
 // Created:    2009.07.13
 
 using NUnit.Framework;
-using System.Linq;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Providers;
 using Xtensive.Orm.Tests.Storage.DbTypeSupportModel;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/Providers/Sql/TableReferenceTest.cs b/Orm/Xtensive.Orm.Tests/Storage/Providers/Sql/TableReferenceTest.cs
index e8fca456a..df34be326 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/Providers/Sql/TableReferenceTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/Providers/Sql/TableReferenceTest.cs
@@ -4,9 +4,6 @@
 // Created by: Aleksey Gamzov
 // Created:    2008.12.23
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Reflection;
 using NUnit.Framework;
 using Xtensive.Sql;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/Providers/Sql/TotalBatchingTest.cs b/Orm/Xtensive.Orm.Tests/Storage/Providers/Sql/TotalBatchingTest.cs
index e25391949..6cba8d957 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/Providers/Sql/TotalBatchingTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/Providers/Sql/TotalBatchingTest.cs
@@ -5,8 +5,6 @@
 // Created:    2009.08.20
 
 using NUnit.Framework;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Collections;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Internals;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/QueryBuilderTest.cs b/Orm/Xtensive.Orm.Tests/Storage/QueryBuilderTest.cs
index f6539e57b..9541b5df9 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/QueryBuilderTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/QueryBuilderTest.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.02.27
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Services;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/QueryResultTest.cs b/Orm/Xtensive.Orm.Tests/Storage/QueryResultTest.cs
index 9c0a28180..4a7207905 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/QueryResultTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/QueryResultTest.cs
@@ -2,12 +2,8 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Collections.Generic;
 using System.Diagnostics;
-using System.Linq;
 using System.Text;
-using System.Threading.Tasks;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Storage.QueryResultTestModel;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/Randomized/RandomizedTest.cs b/Orm/Xtensive.Orm.Tests/Storage/Randomized/RandomizedTest.cs
index 34b177f29..930c5af05 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/Randomized/RandomizedTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/Randomized/RandomizedTest.cs
@@ -4,9 +4,6 @@
 // Created by: Alexander Nikolaev
 // Created:    2009.11.26
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Security.Cryptography;
 using System.Transactions;
 using NUnit.Framework;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/Randomized/Tree.cs b/Orm/Xtensive.Orm.Tests/Storage/Randomized/Tree.cs
index bf1378d0a..4bd9a37e0 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/Randomized/Tree.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/Randomized/Tree.cs
@@ -4,9 +4,7 @@
 // Created by: Alexander Nikolaev
 // Created:    2009.11.26
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
 using Xtensive.Collections;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm.Tests/Storage/Randomized/TreeNode.cs b/Orm/Xtensive.Orm.Tests/Storage/Randomized/TreeNode.cs
index 93e09ca58..db810fc4d 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/Randomized/TreeNode.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/Randomized/TreeNode.cs
@@ -4,7 +4,6 @@
 // Created by: Alexander Nikolaev
 // Created:    2009.11.26
 
-using System;
 using Xtensive.Core;
 
 namespace Xtensive.Orm.Tests.Storage.Randomized
diff --git a/Orm/Xtensive.Orm.Tests/Storage/ReadOnlySupport/ReadOnlyStorageTestBase.cs b/Orm/Xtensive.Orm.Tests/Storage/ReadOnlySupport/ReadOnlyStorageTestBase.cs
index 90fbe4205..6fb757f83 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/ReadOnlySupport/ReadOnlyStorageTestBase.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/ReadOnlySupport/ReadOnlyStorageTestBase.cs
@@ -4,9 +4,7 @@
 // Created by: Alexey Kulakov
 // Created:    2016.03.18
 
-using System;
 using System.Diagnostics;
-using System.Linq;
 using System.Text;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/ReadRemovedObjectTest.cs b/Orm/Xtensive.Orm.Tests/Storage/ReadRemovedObjectTest.cs
index d2ddec228..ab8bae58b 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/ReadRemovedObjectTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/ReadRemovedObjectTest.cs
@@ -4,10 +4,7 @@
 // Created by: Alex Yakunin
 // Created:    2010.06.24
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Orm.Tests;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/RefTest.cs b/Orm/Xtensive.Orm.Tests/Storage/RefTest.cs
index b2c86cab3..582011a64 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/RefTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/RefTest.cs
@@ -4,11 +4,9 @@
 // Created by: Alexis Kochetov
 // Created:    2010.10.01
 
-using System;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Orm.Configuration;
-using System.Linq;
 
 namespace Xtensive.Orm.Tests.Storage.RefTest
 {
diff --git a/Orm/Xtensive.Orm.Tests/Storage/ReferentialIntegrity/ClientProfile/NonPairedReferencesFromEntitiesTest.cs b/Orm/Xtensive.Orm.Tests/Storage/ReferentialIntegrity/ClientProfile/NonPairedReferencesFromEntitiesTest.cs
index c306590c6..e228a9a6c 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/ReferentialIntegrity/ClientProfile/NonPairedReferencesFromEntitiesTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/ReferentialIntegrity/ClientProfile/NonPairedReferencesFromEntitiesTest.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2016.06.22
 
-using System.Collections.Generic;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Storage.ReferentialIntegrity.ClientProfile.NonPairedReferencesFromEntitiesModel;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/ReferentialIntegrity/ClientProfile/NonPairedReferencesFromStructures.cs b/Orm/Xtensive.Orm.Tests/Storage/ReferentialIntegrity/ClientProfile/NonPairedReferencesFromStructures.cs
index f105d5dbd..a1d14e8d2 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/ReferentialIntegrity/ClientProfile/NonPairedReferencesFromStructures.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/ReferentialIntegrity/ClientProfile/NonPairedReferencesFromStructures.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2016.06.22
 
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Model;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/ReferentialIntegrity/ClientProfile/PairedReferencesFromEntitiesTest.cs b/Orm/Xtensive.Orm.Tests/Storage/ReferentialIntegrity/ClientProfile/PairedReferencesFromEntitiesTest.cs
index 6846fb9c7..82a218757 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/ReferentialIntegrity/ClientProfile/PairedReferencesFromEntitiesTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/ReferentialIntegrity/ClientProfile/PairedReferencesFromEntitiesTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2016.06.23
 
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Storage.ReferentialIntegrity.ClientProfile.PairedReferencesFromEntitiesModel;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/ReferentialIntegrity/ClientProfileLike/NonPairedReferencesFromEntitiesTest.cs b/Orm/Xtensive.Orm.Tests/Storage/ReferentialIntegrity/ClientProfileLike/NonPairedReferencesFromEntitiesTest.cs
index 2fe9cb412..47f78ca64 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/ReferentialIntegrity/ClientProfileLike/NonPairedReferencesFromEntitiesTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/ReferentialIntegrity/ClientProfileLike/NonPairedReferencesFromEntitiesTest.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2016.06.22
 
-using System.Collections.Generic;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Storage.ReferentialIntegrity.ClientProfileLike.NonPairedReferencesFromEntitiesModel;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/ReferentialIntegrity/ClientProfileLike/NonPairedReferencesFromStructures.cs b/Orm/Xtensive.Orm.Tests/Storage/ReferentialIntegrity/ClientProfileLike/NonPairedReferencesFromStructures.cs
index 38934c6b3..356c288ff 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/ReferentialIntegrity/ClientProfileLike/NonPairedReferencesFromStructures.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/ReferentialIntegrity/ClientProfileLike/NonPairedReferencesFromStructures.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2016.06.22
 
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Model;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/ReferentialIntegrity/ClientProfileLike/PairedReferencesFromEntitiesTest.cs b/Orm/Xtensive.Orm.Tests/Storage/ReferentialIntegrity/ClientProfileLike/PairedReferencesFromEntitiesTest.cs
index 4d8c3b787..b83ac3030 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/ReferentialIntegrity/ClientProfileLike/PairedReferencesFromEntitiesTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/ReferentialIntegrity/ClientProfileLike/PairedReferencesFromEntitiesTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2016.06.23
 
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Storage.ReferentialIntegrity.ClientProfileLike.PairedReferencesFromEntitiesModel;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/ReferentialIntegrityTest.cs b/Orm/Xtensive.Orm.Tests/Storage/ReferentialIntegrityTest.cs
index d84b28ca9..800af1ce3 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/ReferentialIntegrityTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/ReferentialIntegrityTest.cs
@@ -4,8 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2008.07.01
 
-using System;
-using System.Linq;
 using System.Reflection;
 using NUnit.Framework;
 using Xtensive.Orm.Tests;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/RemapKeysWhenLazyKeyGenerationEnabledTest.cs b/Orm/Xtensive.Orm.Tests/Storage/RemapKeysWhenLazyKeyGenerationEnabledTest.cs
index efd55383e..6e3e5d0be 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/RemapKeysWhenLazyKeyGenerationEnabledTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/RemapKeysWhenLazyKeyGenerationEnabledTest.cs
@@ -4,9 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2014.04.01
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Storage.RemapKeysWhenLazyKeyGenerationEnabledModel;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/RemoveReasonOnEntityRemovingEventTest.cs b/Orm/Xtensive.Orm.Tests/Storage/RemoveReasonOnEntityRemovingEventTest.cs
index 34cb5baa6..7ffdd826a 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/RemoveReasonOnEntityRemovingEventTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/RemoveReasonOnEntityRemovingEventTest.cs
@@ -4,9 +4,6 @@
 // Created by: Denis Kudelin
 // Created:    2018.10.15
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Services;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/SchemaSharing/EntityManipulation/Model.cs b/Orm/Xtensive.Orm.Tests/Storage/SchemaSharing/EntityManipulation/Model.cs
index 49ec9306a..deeb64cac 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/SchemaSharing/EntityManipulation/Model.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/SchemaSharing/EntityManipulation/Model.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2017.04.05
 
-using System;
 
 namespace Xtensive.Orm.Tests.Storage.SchemaSharing.EntityManipulation.Model
 {
diff --git a/Orm/Xtensive.Orm.Tests/Storage/SchemaSharing/EntityManipulation/MultidatabaseEntityManipulationTest.cs b/Orm/Xtensive.Orm.Tests/Storage/SchemaSharing/EntityManipulation/MultidatabaseEntityManipulationTest.cs
index 21bf96227..af5d11e1c 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/SchemaSharing/EntityManipulation/MultidatabaseEntityManipulationTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/SchemaSharing/EntityManipulation/MultidatabaseEntityManipulationTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2017.04.05
 
-using System.Collections.Generic;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Providers;
 using model = Xtensive.Orm.Tests.Storage.SchemaSharing.EntityManipulation.Model;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/SchemaSharing/EntityManipulation/MultischemaEntityManipulationTest.cs b/Orm/Xtensive.Orm.Tests/Storage/SchemaSharing/EntityManipulation/MultischemaEntityManipulationTest.cs
index d22d914b6..795ee31a7 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/SchemaSharing/EntityManipulation/MultischemaEntityManipulationTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/SchemaSharing/EntityManipulation/MultischemaEntityManipulationTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2017.04.05
 
-using System.Collections.Generic;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Providers;
 using model = Xtensive.Orm.Tests.Storage.SchemaSharing.EntityManipulation.Model;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/SchemaSharing/EntityManipulation/SimpleEntityManipulationTest.cs b/Orm/Xtensive.Orm.Tests/Storage/SchemaSharing/EntityManipulation/SimpleEntityManipulationTest.cs
index 7b07cf93c..ac64d2655 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/SchemaSharing/EntityManipulation/SimpleEntityManipulationTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/SchemaSharing/EntityManipulation/SimpleEntityManipulationTest.cs
@@ -4,9 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2017.04.05
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/SchemaSharing/IgnoreRulesTest.cs b/Orm/Xtensive.Orm.Tests/Storage/SchemaSharing/IgnoreRulesTest.cs
index 85a9eb943..ef61757f0 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/SchemaSharing/IgnoreRulesTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/SchemaSharing/IgnoreRulesTest.cs
@@ -4,9 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2017.03.03
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Providers;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/SchemaSharing/KeyGenerator/Model.cs b/Orm/Xtensive.Orm.Tests/Storage/SchemaSharing/KeyGenerator/Model.cs
index d25c4c393..052f0ddaf 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/SchemaSharing/KeyGenerator/Model.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/SchemaSharing/KeyGenerator/Model.cs
@@ -1,6 +1,3 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Text;
 
 namespace Xtensive.Orm.Tests.Storage.SchemaSharing.KeyGenerator.Model
diff --git a/Orm/Xtensive.Orm.Tests/Storage/SchemaSharing/KeyGenerator/MultidatabaseTest.cs b/Orm/Xtensive.Orm.Tests/Storage/SchemaSharing/KeyGenerator/MultidatabaseTest.cs
index 574a22525..7391957a6 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/SchemaSharing/KeyGenerator/MultidatabaseTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/SchemaSharing/KeyGenerator/MultidatabaseTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2017.03.06
 
-using System.Collections.Generic;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Providers;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/SchemaSharing/KeyGenerator/MultischemaTest.cs b/Orm/Xtensive.Orm.Tests/Storage/SchemaSharing/KeyGenerator/MultischemaTest.cs
index bb262c954..abeb301f5 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/SchemaSharing/KeyGenerator/MultischemaTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/SchemaSharing/KeyGenerator/MultischemaTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2017.03.06
 
-using System.Collections.Generic;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Providers;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/SchemaSharing/KeyGenerator/SimpleTest.cs b/Orm/Xtensive.Orm.Tests/Storage/SchemaSharing/KeyGenerator/SimpleTest.cs
index 9ab9dde1d..11375a32b 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/SchemaSharing/KeyGenerator/SimpleTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/SchemaSharing/KeyGenerator/SimpleTest.cs
@@ -2,8 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System.Collections.Generic;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Providers;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/SchemaSharing/Model.cs b/Orm/Xtensive.Orm.Tests/Storage/SchemaSharing/Model.cs
index 79bca128f..d4f8f5d98 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/SchemaSharing/Model.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/SchemaSharing/Model.cs
@@ -2,7 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
 
 namespace Xtensive.Orm.Tests.Storage.SchemaSharing.Model
 {
diff --git a/Orm/Xtensive.Orm.Tests/Storage/SerializationTest.cs b/Orm/Xtensive.Orm.Tests/Storage/SerializationTest.cs
index ccc0269dd..48d5ca180 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/SerializationTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/SerializationTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Kofman
 // Created:    2009.03.19
 
-using System;
 using System.IO;
 using System.Reflection;
 using System.Runtime.Serialization.Formatters.Binary;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/SerializedQueryTest.cs b/Orm/Xtensive.Orm.Tests/Storage/SerializedQueryTest.cs
index a2c6e3493..21502d9ae 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/SerializedQueryTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/SerializedQueryTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2010.02.25
 
-using System;
 using System.IO;
 using NUnit.Framework;
 using Xtensive.Core;
@@ -14,7 +13,6 @@
 using Xtensive.Orm.Serialization;
 using Xtensive.Orm.Tests.ObjectModel;
 using Xtensive.Orm.Tests.ObjectModel.ChinookDO;
-using System.Linq;
 using Xtensive.Orm.Providers;
 
 namespace Xtensive.Orm.Tests.Storage
diff --git a/Orm/Xtensive.Orm.Tests/Storage/SessionDeactivationTest.cs b/Orm/Xtensive.Orm.Tests/Storage/SessionDeactivationTest.cs
index 952c6592b..2648908d7 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/SessionDeactivationTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/SessionDeactivationTest.cs
@@ -4,12 +4,10 @@
 // Created by: Alex Yakunin
 // Created:    2010.06.24
 
-using System;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Orm.Tests;
 using Xtensive.Orm.Configuration;
-using System.Linq;
 
 namespace Xtensive.Orm.Tests.Storage.SessionDeactivationTest
 {
diff --git a/Orm/Xtensive.Orm.Tests/Storage/SessionEventsTest.cs b/Orm/Xtensive.Orm.Tests/Storage/SessionEventsTest.cs
index ab4d3837b..b4782c99f 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/SessionEventsTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/SessionEventsTest.cs
@@ -4,13 +4,10 @@
 // Created by: Alex Kofman
 // Created:    2009.10.08
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Tests;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Storage.SessionEventsTestModel;
-using System.Threading.Tasks;
-using System.Linq;
 
 namespace Xtensive.Orm.Tests.Storage.SessionEventsTestModel
 {
diff --git a/Orm/Xtensive.Orm.Tests/Storage/SessionSaveChangesPerformanceTest.cs b/Orm/Xtensive.Orm.Tests/Storage/SessionSaveChangesPerformanceTest.cs
index 9f3c9de46..dcb7a29c3 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/SessionSaveChangesPerformanceTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/SessionSaveChangesPerformanceTest.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2012.07.25
 
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Storage.SessionSaveChangesPerformanceTestModel;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/SetFieldTest.cs b/Orm/Xtensive.Orm.Tests/Storage/SetFieldTest.cs
index ce0ddb023..0f83d2a5d 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/SetFieldTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/SetFieldTest.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2010.06.24
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/SingleTableTest.cs b/Orm/Xtensive.Orm.Tests/Storage/SingleTableTest.cs
index fda1797ab..cf4e01406 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/SingleTableTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/SingleTableTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2010.10.01
 
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/SkippingValidationOnCommitTest.cs b/Orm/Xtensive.Orm.Tests/Storage/SkippingValidationOnCommitTest.cs
index 5b5b7ab42..51e7ae86b 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/SkippingValidationOnCommitTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/SkippingValidationOnCommitTest.cs
@@ -2,10 +2,7 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Collections.Generic;
 using System.Diagnostics;
-using System.Linq;
 using System.Text;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/StructureReferencesAnEntityTest.cs b/Orm/Xtensive.Orm.Tests/Storage/StructureReferencesAnEntityTest.cs
index ee1331db5..7b7e03b46 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/StructureReferencesAnEntityTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/StructureReferencesAnEntityTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2011.02.16
 
-using System;
 using System.Diagnostics;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/StructureTest.cs b/Orm/Xtensive.Orm.Tests/Storage/StructureTest.cs
index 01d97ad1a..0c20dd539 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/StructureTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/StructureTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2008.05.28
 
-using System;
 using NUnit.Framework;
 using System.Reflection;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/TemporaryTablePopulationTest.cs b/Orm/Xtensive.Orm.Tests/Storage/TemporaryTablePopulationTest.cs
index af816cfea..ca4450955 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/TemporaryTablePopulationTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/TemporaryTablePopulationTest.cs
@@ -2,9 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/TransactionModesTest.cs b/Orm/Xtensive.Orm.Tests/Storage/TransactionModesTest.cs
index bf2d8bad7..f5aa1ef0b 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/TransactionModesTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/TransactionModesTest.cs
@@ -5,7 +5,6 @@
 // Created:    2009.07.30
 
 using NUnit.Framework;
-using System.Linq;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Providers;
 using Xtensive.Orm.Tests.ObjectModel;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/TransactionScopeIntegration.cs b/Orm/Xtensive.Orm.Tests/Storage/TransactionScopeIntegration.cs
index 34986564e..4f0e65351 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/TransactionScopeIntegration.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/TransactionScopeIntegration.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2014.05.12
 
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Storage.TransactionScopeIntegrationTestModel;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/TransactionsTest.cs b/Orm/Xtensive.Orm.Tests/Storage/TransactionsTest.cs
index 38b7aa5fe..286bf0179 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/TransactionsTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/TransactionsTest.cs
@@ -5,7 +5,6 @@
 // Created:    2008.08.27
 
 using NUnit.Framework;
-using System;
 using Xtensive.Orm.Tests;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Providers;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/TypeCompatibilityTest.cs b/Orm/Xtensive.Orm.Tests/Storage/TypeCompatibilityTest.cs
index a5fc844b8..950cca641 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/TypeCompatibilityTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/TypeCompatibilityTest.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2008.09.19
 
-using System;
 using System.Reflection;
 using NUnit.Framework;
 using Xtensive.Orm.Providers;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/TypeDiscriminatorFromInterfaceTest.cs b/Orm/Xtensive.Orm.Tests/Storage/TypeDiscriminatorFromInterfaceTest.cs
index 35d18bfd4..dc95aaec3 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/TypeDiscriminatorFromInterfaceTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/TypeDiscriminatorFromInterfaceTest.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2011.11.15
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Storage.AdvancedDefaultAndTypeDiscriminatorTestModel;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/TypeIdAsParameterTest.cs b/Orm/Xtensive.Orm.Tests/Storage/TypeIdAsParameterTest.cs
index 950440dee..c17d2ced5 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/TypeIdAsParameterTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/TypeIdAsParameterTest.cs
@@ -1,11 +1,7 @@
-using System;
 using System.Collections;
 using System.Collections.Concurrent;
-using System.Collections.Generic;
 using System.Data.Common;
-using System.Linq;
 using System.Text;
-using System.Threading.Tasks;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Storage.TypeIdAsParameterTestModel;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/UnexpectedBehaviorTest.cs b/Orm/Xtensive.Orm.Tests/Storage/UnexpectedBehaviorTest.cs
index 1e7440f1b..29dac30f8 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/UnexpectedBehaviorTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/UnexpectedBehaviorTest.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.12.11
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Storage.UnexpectedBehaviorTestModel;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/UpdateVersionTest.cs b/Orm/Xtensive.Orm.Tests/Storage/UpdateVersionTest.cs
index 52f1e8e4c..a29a56b9a 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/UpdateVersionTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/UpdateVersionTest.cs
@@ -4,12 +4,10 @@
 // Created by: Ivan Galkin
 // Created:    2009.10.06
 
-using System;
 using System.Reflection;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Orm.Configuration;
-using System.Linq;
 using M=Xtensive.Orm.Model;
 
 #region Model
diff --git a/Orm/Xtensive.Orm.Tests/Storage/UpgradeModesTest.cs b/Orm/Xtensive.Orm.Tests/Storage/UpgradeModesTest.cs
index a03ed7a91..f6db74cd5 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/UpgradeModesTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/UpgradeModesTest.cs
@@ -4,9 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2010.06.24
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Orm.Tests;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/ValidateEntityVersionsOnPersistTest.cs b/Orm/Xtensive.Orm.Tests/Storage/ValidateEntityVersionsOnPersistTest.cs
index 6e883e9af..3c725010e 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/ValidateEntityVersionsOnPersistTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/ValidateEntityVersionsOnPersistTest.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2013.04.22
 
-using System.Linq;
 using NUnit.Framework;
 using ValidateEntityVersionsOnPersistTestModel;
 using Xtensive.Orm;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/ValidateOnlyModifiedFieldsTest.cs b/Orm/Xtensive.Orm.Tests/Storage/ValidateOnlyModifiedFieldsTest.cs
index 487b9fa02..20d6445c8 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/ValidateOnlyModifiedFieldsTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/ValidateOnlyModifiedFieldsTest.cs
@@ -4,8 +4,6 @@
 // Created by: Julian Mamokin
 // Created:    2017.08.18
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Validation;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/ValidationConstraintsOnGenericTypeTest.cs b/Orm/Xtensive.Orm.Tests/Storage/ValidationConstraintsOnGenericTypeTest.cs
index 87ad888cc..e9ef79369 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/ValidationConstraintsOnGenericTypeTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/ValidationConstraintsOnGenericTypeTest.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.12.19
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Model;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/ValidationContextClientProfileTest.cs b/Orm/Xtensive.Orm.Tests/Storage/ValidationContextClientProfileTest.cs
index 7f60a5faf..bf4a71aa1 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/ValidationContextClientProfileTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/ValidationContextClientProfileTest.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.04.25
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Storage.ValidationContextClientProfileModel;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/ValidationContextTest.cs b/Orm/Xtensive.Orm.Tests/Storage/ValidationContextTest.cs
index 22a95b71d..48b616495 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/ValidationContextTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/ValidationContextTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Kofman
 // Created:    2009.09.15
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Validation;
 using Xtensive.Orm.Tests;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/ValidationOnDemandTest.cs b/Orm/Xtensive.Orm.Tests/Storage/ValidationOnDemandTest.cs
index 611d2109d..75754d148 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/ValidationOnDemandTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/ValidationOnDemandTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Kofman
 // Created:    2009.09.30
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Validation;
 using Xtensive.Orm.Tests;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/ValidationReferentialTest.cs b/Orm/Xtensive.Orm.Tests/Storage/ValidationReferentialTest.cs
index 702a33a82..32c7b635f 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/ValidationReferentialTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/ValidationReferentialTest.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Kofman
 // Created:    2009.06.08
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Storage.ValidationReferentialTestModel;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/ValidationTest.cs b/Orm/Xtensive.Orm.Tests/Storage/ValidationTest.cs
index 9c3558310..2a52d12c1 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/ValidationTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/ValidationTest.cs
@@ -4,10 +4,7 @@
 // Created by: Alex Kofman
 // Created:    2008.08.31
 
-using System;
-using System.Linq;
 using System.Reflection;
-using System.Threading;
 using NUnit.Framework;
 using Xtensive.Orm.Validation;
 using Xtensive.Orm.Tests;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/VersionBehaviorTest.cs b/Orm/Xtensive.Orm.Tests/Storage/VersionBehaviorTest.cs
index 3b3cf95b1..111117876 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/VersionBehaviorTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/VersionBehaviorTest.cs
@@ -4,8 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2010.08.05
 
-using System;
-using System.Linq;
 using System.Diagnostics;
 using NUnit.Framework;
 using Xtensive.Orm.Tests;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/VersionRootTests.cs b/Orm/Xtensive.Orm.Tests/Storage/VersionRootTests.cs
index 9ce899b0b..2d4294bec 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/VersionRootTests.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/VersionRootTests.cs
@@ -4,13 +4,10 @@
 // Created by: Ivan Galkin
 // Created:    2009.10.06
 
-using System;
-using System.Collections.Generic;
 using System.Reflection;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Orm.Configuration;
-using System.Linq;
 using Xtensive.Collections;
 
 #region Model
diff --git a/Orm/Xtensive.Orm.Tests/Storage/VersionValidationTest.cs b/Orm/Xtensive.Orm.Tests/Storage/VersionValidationTest.cs
index 1e23d2580..72597f6e6 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/VersionValidationTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/VersionValidationTest.cs
@@ -4,12 +4,10 @@
 // Created by: Ivan Galkin
 // Created:    2009.11.11
 
-using System;
 using System.Reflection;
 using NUnit.Framework;
 using Xtensive.Orm.Tests;
 using Xtensive.Orm.Configuration;
-using System.Linq;
 //using Xtensive.Orm.Disconnected;
 
 #region Model
diff --git a/Orm/Xtensive.Orm.Tests/Storage/Versioning/EntitySetOnwerVersionChangeTest.cs b/Orm/Xtensive.Orm.Tests/Storage/Versioning/EntitySetOnwerVersionChangeTest.cs
index 96a66ef91..3f0cfb11e 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/Versioning/EntitySetOnwerVersionChangeTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/Versioning/EntitySetOnwerVersionChangeTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2018.03.02
 
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Storage.VersioningConventionTestModel;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/Versioning/EntityVersioningPolicyTest.cs b/Orm/Xtensive.Orm.Tests/Storage/Versioning/EntityVersioningPolicyTest.cs
index 16a46323b..210325420 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/Versioning/EntityVersioningPolicyTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/Versioning/EntityVersioningPolicyTest.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2018.03.02
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Storage.VersioningConventionTestModel;
diff --git a/Orm/Xtensive.Orm.Tests/Storage/Versioning/Model.cs b/Orm/Xtensive.Orm.Tests/Storage/Versioning/Model.cs
index 797cfb111..593c9569b 100644
--- a/Orm/Xtensive.Orm.Tests/Storage/Versioning/Model.cs
+++ b/Orm/Xtensive.Orm.Tests/Storage/Versioning/Model.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2018.03.02
 
-using System;
 using System.Text;
 
 namespace Xtensive.Orm.Tests.Storage.VersioningConventionTestModel
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/BuildOnEmptySchemaTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/BuildOnEmptySchemaTest.cs
index b9be26a0d..250e34e18 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/BuildOnEmptySchemaTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/BuildOnEmptySchemaTest.cs
@@ -4,9 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2016.02.09
 
-using System;
-using System.Linq;
-using System.Threading.Tasks;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Model;
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/ChangeColumnCaseTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/ChangeColumnCaseTest.cs
index ea52ae09c..03d49d6b9 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/ChangeColumnCaseTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/ChangeColumnCaseTest.cs
@@ -4,10 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.11.15
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Threading.Tasks;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Upgrade;
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/ChangeFulltextCatalogTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/ChangeFulltextCatalogTest.cs
index 90d3ed06d..d55051cb2 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/ChangeFulltextCatalogTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/ChangeFulltextCatalogTest.cs
@@ -10,7 +10,6 @@
 using Xtensive.Orm.Providers;
 using Xtensive.Orm.Upgrade;
 using Xtensive.Orm.Tests.Upgrade.ChangeFulltextCatalogTestModel;
-using System.Threading.Tasks;
 
 namespace Xtensive.Orm.Tests.Upgrade.ChangeFulltextCatalogTestModel
 {
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/ChangeNamespaceTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/ChangeNamespaceTest.cs
index f3bc765b0..ab069e3b9 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/ChangeNamespaceTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/ChangeNamespaceTest.cs
@@ -4,9 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2013.04.08
 
-using System;
-using System.Linq;
-using System.Threading.Tasks;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Upgrade.ChangeNamespaceTestModel;
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/ColumnTypeTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/ColumnTypeTest.cs
index afc20cdde..ee73f361f 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/ColumnTypeTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/ColumnTypeTest.cs
@@ -4,10 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.06.04
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Threading.Tasks;
 using NUnit.Framework;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/ConflictsByTable/ColumnTypeChangeInNewHierarchy.cs b/Orm/Xtensive.Orm.Tests/Upgrade/ConflictsByTable/ColumnTypeChangeInNewHierarchy.cs
index 5df1d3a74..0af3e167d 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/ConflictsByTable/ColumnTypeChangeInNewHierarchy.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/ConflictsByTable/ColumnTypeChangeInNewHierarchy.cs
@@ -2,11 +2,7 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Text;
-using System.Threading.Tasks;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Modelling.Actions;
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/ConflictsByTable/ComplexTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/ConflictsByTable/ComplexTest.cs
index a8523e309..77a071a9f 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/ConflictsByTable/ComplexTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/ConflictsByTable/ComplexTest.cs
@@ -2,9 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Text;
 using NUnit.Framework;
 using Xtensive.Modelling.Actions;
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/ConflictsByTable/ComplextTestModel.cs b/Orm/Xtensive.Orm.Tests/Upgrade/ConflictsByTable/ComplextTestModel.cs
index 8b7cccac2..e64e8ed42 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/ConflictsByTable/ComplextTestModel.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/ConflictsByTable/ComplextTestModel.cs
@@ -2,8 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Collections.Generic;
 using System.Text;
 using Xtensive.Orm.Building;
 using Xtensive.Orm.Building.Definitions;
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/ConflictsByTable/ExactTableStructureNoGeneratorTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/ConflictsByTable/ExactTableStructureNoGeneratorTest.cs
index 446f2beed..d6f085f42 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/ConflictsByTable/ExactTableStructureNoGeneratorTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/ConflictsByTable/ExactTableStructureNoGeneratorTest.cs
@@ -2,11 +2,7 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Text;
-using System.Threading.Tasks;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Modelling.Actions;
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/ConflictsByTable/ExactTableStructureWithGeneratorTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/ConflictsByTable/ExactTableStructureWithGeneratorTest.cs
index 5ab5be2af..15de5dcab 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/ConflictsByTable/ExactTableStructureWithGeneratorTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/ConflictsByTable/ExactTableStructureWithGeneratorTest.cs
@@ -2,11 +2,7 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Text;
-using System.Threading.Tasks;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Modelling.Actions;
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/ConflictsByTable/NewColumnInNewHierarchyTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/ConflictsByTable/NewColumnInNewHierarchyTest.cs
index ee6758f8b..15362061d 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/ConflictsByTable/NewColumnInNewHierarchyTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/ConflictsByTable/NewColumnInNewHierarchyTest.cs
@@ -2,11 +2,7 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Text;
-using System.Threading.Tasks;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Modelling.Actions;
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/ConflictsByTable/PrimaryKeyNameChangedNoGeneratorTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/ConflictsByTable/PrimaryKeyNameChangedNoGeneratorTest.cs
index acac8aaec..17d656475 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/ConflictsByTable/PrimaryKeyNameChangedNoGeneratorTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/ConflictsByTable/PrimaryKeyNameChangedNoGeneratorTest.cs
@@ -2,11 +2,7 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Text;
-using System.Threading.Tasks;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Modelling.Actions;
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/ConflictsByTable/PrimaryKeyNameChangedWithGeneratorTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/ConflictsByTable/PrimaryKeyNameChangedWithGeneratorTest.cs
index cd6ae93a9..aaa6599f8 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/ConflictsByTable/PrimaryKeyNameChangedWithGeneratorTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/ConflictsByTable/PrimaryKeyNameChangedWithGeneratorTest.cs
@@ -2,11 +2,7 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Text;
-using System.Threading.Tasks;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Modelling.Actions;
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/ConflictsByTable/RemovedColumnInNewHierarchyTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/ConflictsByTable/RemovedColumnInNewHierarchyTest.cs
index 64e8f7973..425e4f7ea 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/ConflictsByTable/RemovedColumnInNewHierarchyTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/ConflictsByTable/RemovedColumnInNewHierarchyTest.cs
@@ -2,11 +2,7 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Text;
-using System.Threading.Tasks;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Modelling.Actions;
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/ConflictsByTable/RenamedColumnInNewHierarchyTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/ConflictsByTable/RenamedColumnInNewHierarchyTest.cs
index b56d15edf..ff71a57ec 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/ConflictsByTable/RenamedColumnInNewHierarchyTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/ConflictsByTable/RenamedColumnInNewHierarchyTest.cs
@@ -2,11 +2,7 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Text;
-using System.Threading.Tasks;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Modelling.Actions;
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/ConflictsByTable/TestBase.cs b/Orm/Xtensive.Orm.Tests/Upgrade/ConflictsByTable/TestBase.cs
index f5744c280..85d905834 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/ConflictsByTable/TestBase.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/ConflictsByTable/TestBase.cs
@@ -2,11 +2,7 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Text;
-using System.Threading.Tasks;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Modelling.Actions;
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/CustomTypeIdMap/CustomTypeIdMap.cs b/Orm/Xtensive.Orm.Tests/Upgrade/CustomTypeIdMap/CustomTypeIdMap.cs
index fd68d5d6d..84516a2e4 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/CustomTypeIdMap/CustomTypeIdMap.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/CustomTypeIdMap/CustomTypeIdMap.cs
@@ -5,10 +5,7 @@
 // Created:    2014.07.18
 
 
-using System;
-using System.Collections.Generic;
 using NUnit.Framework;
-using System.Linq;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Providers;
 using Xtensive.Orm.Upgrade;
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/DataUpgrade/DataUpgradeTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/DataUpgrade/DataUpgradeTest.cs
index a44067244..06f40b23c 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/DataUpgrade/DataUpgradeTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/DataUpgrade/DataUpgradeTest.cs
@@ -4,10 +4,7 @@
 // Created by: Ivan Galkin
 // Created:    2009.05.30
 
-using System;
-using System.Linq;
 using System.Reflection;
-using System.Threading.Tasks;
 using NUnit.Framework;
 
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/DataUpgrade/Model1.cs b/Orm/Xtensive.Orm.Tests/Upgrade/DataUpgrade/Model1.cs
index f7809e3a7..39462249d 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/DataUpgrade/Model1.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/DataUpgrade/Model1.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.05.30
 
-using System;
 
 namespace Xtensive.Orm.Tests.Upgrade.DataUpgrade.Model.Version1
 {
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/DataUpgrade/Model2.cs b/Orm/Xtensive.Orm.Tests/Upgrade/DataUpgrade/Model2.cs
index d23219fd0..648f79d28 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/DataUpgrade/Model2.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/DataUpgrade/Model2.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.05.30
 
-using System;
 
 namespace Xtensive.Orm.Tests.Upgrade.DataUpgrade.Model.Version2
 {
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/DataUpgrade/Upgrader.cs b/Orm/Xtensive.Orm.Tests/Upgrade/DataUpgrade/Upgrader.cs
index b40214ac7..f69f696a5 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/DataUpgrade/Upgrader.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/DataUpgrade/Upgrader.cs
@@ -4,8 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.05.20
 
-using System;
-using System.Collections.Generic;
 using Xtensive.Core;
 using Xtensive.Collections;
 
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/DateTimeDataConversions.cs b/Orm/Xtensive.Orm.Tests/Upgrade/DateTimeDataConversions.cs
index f55f0202b..c36d883bf 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/DateTimeDataConversions.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/DateTimeDataConversions.cs
@@ -2,9 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Reflection;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/DateTimeOffsetUpgradeTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/DateTimeOffsetUpgradeTest.cs
index b98133eaa..f3e0dace8 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/DateTimeOffsetUpgradeTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/DateTimeOffsetUpgradeTest.cs
@@ -4,9 +4,6 @@
 // Created by: Alex Groznov
 // Created:    2016.08.31
 
-using System;
-using System.Linq;
-using System.Threading.Tasks;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Providers;
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/DisableAutoResolveNamespaceConflictsTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/DisableAutoResolveNamespaceConflictsTest.cs
index ac33a9610..63f2d2c41 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/DisableAutoResolveNamespaceConflictsTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/DisableAutoResolveNamespaceConflictsTest.cs
@@ -4,11 +4,7 @@
 // Created by: Alexey Kulakov
 // Created:    2014.05.29
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Text;
-using System.Threading.Tasks;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Upgrade;
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/DomainUpgradeSimpleTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/DomainUpgradeSimpleTest.cs
index 8c1b37237..31a17ce24 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/DomainUpgradeSimpleTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/DomainUpgradeSimpleTest.cs
@@ -4,10 +4,8 @@
 // Created by: Alexis Kochetov
 // Created:    2010.01.15
 
-using System;
 using System.Diagnostics;
 using System.Reflection;
-using System.Threading.Tasks;
 using NUnit.Framework;
 
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/DomainUpgradeTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/DomainUpgradeTest.cs
index f59672238..ef5917088 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/DomainUpgradeTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/DomainUpgradeTest.cs
@@ -4,8 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.05.20
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using System.Reflection;
 
@@ -38,7 +36,6 @@
 using StructureContainer2 = Xtensive.Orm.Tests.Upgrade.Model.Version2.StructureContainer2;
 using StructureContainer3 = Xtensive.Orm.Tests.Upgrade.Model.Version2.StructureContainer3;
 using StructureContainer4 = Xtensive.Orm.Tests.Upgrade.Model.Version2.StructureContainer4;
-using System.Threading.Tasks;
 
 namespace Xtensive.Orm.Tests.Upgrade
 {
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/EntitySetUpgrade/ModelVersion1.cs b/Orm/Xtensive.Orm.Tests/Upgrade/EntitySetUpgrade/ModelVersion1.cs
index 09acea8a8..d07451b45 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/EntitySetUpgrade/ModelVersion1.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/EntitySetUpgrade/ModelVersion1.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.05.20
 
-using System;
 
 namespace Xtensive.Orm.Tests.Upgrade.EntitySetUpgradeTest.Model.Version1
 {
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/EntitySetUpgrade/ModelVersion2.cs b/Orm/Xtensive.Orm.Tests/Upgrade/EntitySetUpgrade/ModelVersion2.cs
index 1f7778977..bd6f5c247 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/EntitySetUpgrade/ModelVersion2.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/EntitySetUpgrade/ModelVersion2.cs
@@ -5,11 +5,9 @@
 // Created:    2009.05.20
 
 using System.Collections;
-using System.Linq;
 using Xtensive.Collections;
 using Xtensive.Core;
 using Xtensive.Orm.Upgrade;
-using System;
 
 namespace Xtensive.Orm.Tests.Upgrade.EntitySetUpgradeTest.Model.Version2
 {
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/EntitySetUpgrade/UpgradeTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/EntitySetUpgrade/UpgradeTest.cs
index b880d09f1..7bb2c3081 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/EntitySetUpgrade/UpgradeTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/EntitySetUpgrade/UpgradeTest.cs
@@ -4,15 +4,12 @@
 // Created by: Ivan Galkin
 // Created:    2009.05.20
 
-using System;
-using System.Linq;
 using System.Reflection;
 using Xtensive.Core;
 using Xtensive.Orm.Tests.Upgrade.EntitySetUpgradeTest.Model.Version1;
 using M1 = Xtensive.Orm.Tests.Upgrade.EntitySetUpgradeTest.Model.Version1;
 using M2 = Xtensive.Orm.Tests.Upgrade.EntitySetUpgradeTest.Model.Version2;
 using NUnit.Framework;
-using System.Threading.Tasks;
 
 namespace Xtensive.Orm.Tests.Upgrade.EntitySetUpgradeTest
 {
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/EntitySetUpgrade/Upgrader.cs b/Orm/Xtensive.Orm.Tests/Upgrade/EntitySetUpgrade/Upgrader.cs
index b40ed0b66..e49a7a71f 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/EntitySetUpgrade/Upgrader.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/EntitySetUpgrade/Upgrader.cs
@@ -4,9 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.05.20
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Core;
 
 using Xtensive.Orm.Upgrade;
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/ExtractSuperClassTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/ExtractSuperClassTest.cs
index b49bbfe99..ad8616749 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/ExtractSuperClassTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/ExtractSuperClassTest.cs
@@ -4,10 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.04.24
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Threading.Tasks;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Model;
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/FullText/ChangeTrackingModeComparisonTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/FullText/ChangeTrackingModeComparisonTest.cs
index b79ab61b6..39e23adcd 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/FullText/ChangeTrackingModeComparisonTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/FullText/ChangeTrackingModeComparisonTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2017.07.17
 
-using System.Threading.Tasks;
 using NUnit.Framework;
 using Xtensive.Orm.Providers;
 using Xtensive.Orm.Tests.Upgrade.FullText.Model.Version2;
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/FullText/ConvertionToStorageModelTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/FullText/ConvertionToStorageModelTest.cs
index 08a213bd0..aa71728da 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/FullText/ConvertionToStorageModelTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/FullText/ConvertionToStorageModelTest.cs
@@ -4,13 +4,11 @@
 // Created by: Alexey Kulakov
 // Created:    2017.07.17
 
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Providers;
 using Xtensive.Orm.Upgrade;
 using Xtensive.Orm.Upgrade.Model;
 using Xtensive.Orm.Tests.Upgrade.FullText.ConversionToStorageModelModel;
-using System.Threading.Tasks;
 
 namespace Xtensive.Orm.Tests.Upgrade.FullText.ConversionToStorageModelModel
 {
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/FullText/DomainUpgradeFullTestTest.Models.cs b/Orm/Xtensive.Orm.Tests/Upgrade/FullText/DomainUpgradeFullTestTest.Models.cs
index ad6155c02..6b27efe59 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/FullText/DomainUpgradeFullTestTest.Models.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/FullText/DomainUpgradeFullTestTest.Models.cs
@@ -4,8 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2010.01.21
 
-using System;
-using System.Collections.Generic;
 using Xtensive.Core;
 using Xtensive.Orm.Upgrade;
 
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/FullText/DomainUpgradeFullTextTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/FullText/DomainUpgradeFullTextTest.cs
index 6ffab3439..596b6b7cb 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/FullText/DomainUpgradeFullTextTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/FullText/DomainUpgradeFullTextTest.cs
@@ -4,10 +4,8 @@
 // Created by: Alexis Kochetov
 // Created:    2010.01.21
 
-using System;
 using System.Diagnostics;
 using System.Reflection;
-using System.Threading.Tasks;
 using NUnit.Framework;
 
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/FullText/DynamicFullTextCatalogTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/FullText/DynamicFullTextCatalogTest.cs
index cc4e5bf8c..92945ef9b 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/FullText/DynamicFullTextCatalogTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/FullText/DynamicFullTextCatalogTest.cs
@@ -13,7 +13,6 @@
 using Xtensive.Orm.Upgrade.Model;
 using Database1 = Xtensive.Orm.Tests.Upgrade.DynamicFulltextCatalogTestModel.Database1;
 using Database2 = Xtensive.Orm.Tests.Upgrade.DynamicFulltextCatalogTestModel.Database2;
-using System.Threading.Tasks;
 
 namespace Xtensive.Orm.Tests.Upgrade.DynamicFulltextCatalogTestModel
 {
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/FullText/FullTextCatalogNameBuilderRegistrationTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/FullText/FullTextCatalogNameBuilderRegistrationTest.cs
index cdad2d963..a2d3f709c 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/FullText/FullTextCatalogNameBuilderRegistrationTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/FullText/FullTextCatalogNameBuilderRegistrationTest.cs
@@ -4,9 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2017.07.12
 
-using System;
-using System.Linq;
-using System.Threading.Tasks;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/FullText/FullTextDataTypeColumnUpgradeTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/FullText/FullTextDataTypeColumnUpgradeTest.cs
index 22fc247d7..fd3688038 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/FullText/FullTextDataTypeColumnUpgradeTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/FullText/FullTextDataTypeColumnUpgradeTest.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2013.11.14
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Orm.Building.Definitions;
@@ -21,7 +19,6 @@
 using wrongModel2 = Xtensive.Orm.Tests.Upgrade.FullTextDataTypeColumnUpgrageTestModel7;
 using wrongModel3 = Xtensive.Orm.Tests.Upgrade.FullTextDataTypeColumnUpgrageTestModel8;
 using wrongModel4 = Xtensive.Orm.Tests.Upgrade.FullTextDataTypeColumnUpgrageTestModel9;
-using System.Threading.Tasks;
 
 namespace Xtensive.Orm.Tests.Upgrade.FullTextDataTypeColumnUpgrageTestModel1
 {
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/GeneratorUpgrade/Model.cs b/Orm/Xtensive.Orm.Tests/Upgrade/GeneratorUpgrade/Model.cs
index a2ecfd508..f437c39a4 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/GeneratorUpgrade/Model.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/GeneratorUpgrade/Model.cs
@@ -4,9 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2019.12.10
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Text;
 
 namespace Xtensive.Orm.Tests.Upgrade.GeneratorUpgrade
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/GeneratorUpgrade/MultidatabaseTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/GeneratorUpgrade/MultidatabaseTest.cs
index c19a6372b..ee2df4f28 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/GeneratorUpgrade/MultidatabaseTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/GeneratorUpgrade/MultidatabaseTest.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2019.12.10
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Collections;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/GeneratorUpgrade/MultischemaTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/GeneratorUpgrade/MultischemaTest.cs
index 61b44ab7e..8549b9374 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/GeneratorUpgrade/MultischemaTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/GeneratorUpgrade/MultischemaTest.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2019.12.10
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Collections;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/GeneratorUpgrade/SimpleSchemaTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/GeneratorUpgrade/SimpleSchemaTest.cs
index 5ba0ec6c0..3a4338ebf 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/GeneratorUpgrade/SimpleSchemaTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/GeneratorUpgrade/SimpleSchemaTest.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Kudelin
 // Created:    2018.10.10
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Collections;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/HugeModelUpgrade/DatabasePerNodeTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/HugeModelUpgrade/DatabasePerNodeTest.cs
index bf2bd2bed..cbaa336a5 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/HugeModelUpgrade/DatabasePerNodeTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/HugeModelUpgrade/DatabasePerNodeTest.cs
@@ -4,9 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2016.10.19
 
-using System;
-using System.Collections.Generic;
-using System.Threading.Tasks;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Upgrade.HugeModelUpgrade.RegularModel;
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/HugeModelUpgrade/HugeModelUpgradeTestBase.cs b/Orm/Xtensive.Orm.Tests/Upgrade/HugeModelUpgrade/HugeModelUpgradeTestBase.cs
index 1ccc04ae5..9eac7def2 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/HugeModelUpgrade/HugeModelUpgradeTestBase.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/HugeModelUpgrade/HugeModelUpgradeTestBase.cs
@@ -2,10 +2,7 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Collections.Generic;
 using System.Text;
-using System.Threading.Tasks;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/HugeModelUpgrade/MappedTypesNodesTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/HugeModelUpgrade/MappedTypesNodesTest.cs
index f6f5ae1a2..261589943 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/HugeModelUpgrade/MappedTypesNodesTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/HugeModelUpgrade/MappedTypesNodesTest.cs
@@ -4,9 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2016.10.19
 
-using System;
-using System.Collections.Generic;
-using System.Threading.Tasks;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Upgrade.HugeModelUpgrade.ModelWithMappings;
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/HugeModelUpgrade/Models/ModelWithMappedTypes.cs b/Orm/Xtensive.Orm.Tests/Upgrade/HugeModelUpgrade/Models/ModelWithMappedTypes.cs
index 204c3fdce..3a354f179 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/HugeModelUpgrade/Models/ModelWithMappedTypes.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/HugeModelUpgrade/Models/ModelWithMappedTypes.cs
@@ -1,6 +1,4 @@
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 
 namespace Xtensive.Orm.Tests.Upgrade.HugeModelUpgrade.ModelWithMappings
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/HugeModelUpgrade/Models/RegularModel.cs b/Orm/Xtensive.Orm.Tests/Upgrade/HugeModelUpgrade/Models/RegularModel.cs
index 99b3df84c..2f50af46f 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/HugeModelUpgrade/Models/RegularModel.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/HugeModelUpgrade/Models/RegularModel.cs
@@ -1,5 +1,3 @@
-using System;
-using System.Linq;
 using NUnit.Framework;
 
 namespace Xtensive.Orm.Tests.Upgrade.HugeModelUpgrade.RegularModel
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/HugeModelUpgrade/Models/TwoPartsModel.cs b/Orm/Xtensive.Orm.Tests/Upgrade/HugeModelUpgrade/Models/TwoPartsModel.cs
index a401de53c..73dddac2c 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/HugeModelUpgrade/Models/TwoPartsModel.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/HugeModelUpgrade/Models/TwoPartsModel.cs
@@ -1,5 +1,3 @@
-using System;
-using System.Linq;
 using NUnit.Framework;
 
 namespace Xtensive.Orm.Tests.Upgrade.HugeModelUpgrade.TwoPartsModel
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/HugeModelUpgrade/PerformanceResultContainer.cs b/Orm/Xtensive.Orm.Tests/Upgrade/HugeModelUpgrade/PerformanceResultContainer.cs
index a2cb1fefc..b61514b39 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/HugeModelUpgrade/PerformanceResultContainer.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/HugeModelUpgrade/PerformanceResultContainer.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2016.10.19
 
-using System;
-using System.Collections.Generic;
 using System.Text;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/HugeModelUpgrade/SchemaPerNodeTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/HugeModelUpgrade/SchemaPerNodeTest.cs
index 01cf25412..ff6f4bd16 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/HugeModelUpgrade/SchemaPerNodeTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/HugeModelUpgrade/SchemaPerNodeTest.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2016.10.19
 
-using System;
-using System.Collections.Generic;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Upgrade.HugeModelUpgrade.RegularModel;
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/HugeModelUpgrade/TwoDatabasesPerNodeTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/HugeModelUpgrade/TwoDatabasesPerNodeTest.cs
index 7f7374dc7..4769808a7 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/HugeModelUpgrade/TwoDatabasesPerNodeTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/HugeModelUpgrade/TwoDatabasesPerNodeTest.cs
@@ -4,9 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2016.10.19
 
-using System;
-using System.Collections.Generic;
-using System.Threading.Tasks;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Upgrade.HugeModelUpgrade.TwoPartsModel;
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/HugeModelUpgrade/TwoSchemasPerNodeTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/HugeModelUpgrade/TwoSchemasPerNodeTest.cs
index 1ee0c02c7..ddec4d7b3 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/HugeModelUpgrade/TwoSchemasPerNodeTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/HugeModelUpgrade/TwoSchemasPerNodeTest.cs
@@ -4,9 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2016.10.24
 
-using System;
-using System.Collections.Generic;
-using System.Threading.Tasks;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Upgrade.HugeModelUpgrade;
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/HugeModelUpgrade/UpgradePerformanceCounter.cs b/Orm/Xtensive.Orm.Tests/Upgrade/HugeModelUpgrade/UpgradePerformanceCounter.cs
index 3925f0177..e8629a5c7 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/HugeModelUpgrade/UpgradePerformanceCounter.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/HugeModelUpgrade/UpgradePerformanceCounter.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2016.10.19
 
-using System;
-using System.Collections.Generic;
 using Xtensive.Orm.Upgrade;
 
 namespace Xtensive.Orm.Tests.Upgrade.HugeModelUpgrade
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/IgnoreHintsTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/IgnoreHintsTest.cs
index e413ecd57..ce14c46df 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/IgnoreHintsTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/IgnoreHintsTest.cs
@@ -4,8 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.06.19
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Core;
 
@@ -14,7 +12,6 @@
 using Xtensive.Orm.Tests.Upgrade.IgnoreHints.Model;
 using Xtensive.Orm.Upgrade;
 using Xtensive.Orm.Building;
-using System.Threading.Tasks;
 
 namespace Xtensive.Orm.Tests.Upgrade
 {
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/KeyGeneratorTableCleanUpTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/KeyGeneratorTableCleanUpTest.cs
index 0b0f7ebe2..6e194f9d5 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/KeyGeneratorTableCleanUpTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/KeyGeneratorTableCleanUpTest.cs
@@ -4,10 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.09.28
 
-using System;
-using System.Collections.Generic;
-using System.Threading;
-using System.Threading.Tasks;
 using NUnit.Framework;
 using Xtensive.Orm.Providers;
 using Xtensive.Orm.Upgrade;
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/LegacyUpgrade/LegacyUpgradeTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/LegacyUpgrade/LegacyUpgradeTest.cs
index 71d1705bb..50c6b3b80 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/LegacyUpgrade/LegacyUpgradeTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/LegacyUpgrade/LegacyUpgradeTest.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.11.20
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Tests;
 using Xtensive.Sql;
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/ModelConversion/ConvertDomainModelTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/ModelConversion/ConvertDomainModelTest.cs
index 805bffd65..970ac6056 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/ModelConversion/ConvertDomainModelTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/ModelConversion/ConvertDomainModelTest.cs
@@ -4,9 +4,7 @@
 // Created by: Ivan Galkin
 // Created:    2009.03.23
 
-using System.Linq;
 using NUnit.Framework;
-using System;
 using System.Reflection;
 using Xtensive.Core;
 using Xtensive.Orm.Upgrade;
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/ModelConversion/ForeignKeysTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/ModelConversion/ForeignKeysTest.cs
index 47913985a..d54afaa07 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/ModelConversion/ForeignKeysTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/ModelConversion/ForeignKeysTest.cs
@@ -4,8 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.08.11
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/ModelVersion1.cs b/Orm/Xtensive.Orm.Tests/Upgrade/ModelVersion1.cs
index 766f896d7..4e33c5071 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/ModelVersion1.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/ModelVersion1.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.05.20
 
-using System;
 
 namespace Xtensive.Orm.Tests.Upgrade.Model.Version1
 {
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/ModelVersion2.cs b/Orm/Xtensive.Orm.Tests/Upgrade/ModelVersion2.cs
index f5daea329..4a4ed8a5a 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/ModelVersion2.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/ModelVersion2.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.05.20
 
-using System;
 using Xtensive.Orm.Model;
 
 namespace Xtensive.Orm.Tests.Upgrade.Model.Version2
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/ModelVersion3.cs b/Orm/Xtensive.Orm.Tests/Upgrade/ModelVersion3.cs
index 69d0e56ce..867b30f64 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/ModelVersion3.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/ModelVersion3.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.05.20
 
-using System;
 
 namespace Xtensive.Orm.Tests.Upgrade.Model.Version3
 {
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/NewSkip/Model.cs b/Orm/Xtensive.Orm.Tests/Upgrade/NewSkip/Model.cs
index 442542e8d..043d42e1b 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/NewSkip/Model.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/NewSkip/Model.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2016.02.24
 
-using System;
 using System.Linq.Expressions;
 using System.Security.Cryptography;
 using System.Text;
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/NewSkip/MultidatabaseDomainTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/NewSkip/MultidatabaseDomainTest.cs
index 555e65627..ae1fd2d3e 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/NewSkip/MultidatabaseDomainTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/NewSkip/MultidatabaseDomainTest.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2016.02.24
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Providers;
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/NewSkip/MultischemaDomainTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/NewSkip/MultischemaDomainTest.cs
index 9864d2a37..2a973475e 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/NewSkip/MultischemaDomainTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/NewSkip/MultischemaDomainTest.cs
@@ -2,8 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Providers;
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/NewSkip/SimpleDomainTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/NewSkip/SimpleDomainTest.cs
index 31d06e16e..50b3223b0 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/NewSkip/SimpleDomainTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/NewSkip/SimpleDomainTest.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2016.02.24
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Tests.Upgrade.NewSkip.Model.Users;
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/NewSkip/SingleDatabaseNodeTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/NewSkip/SingleDatabaseNodeTest.cs
index fb1b29c33..7a0482ee1 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/NewSkip/SingleDatabaseNodeTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/NewSkip/SingleDatabaseNodeTest.cs
@@ -4,9 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2016.02.24
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Providers;
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/NewSkip/SingleSchemaNodeBuildingTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/NewSkip/SingleSchemaNodeBuildingTest.cs
index 72ee68630..756a46826 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/NewSkip/SingleSchemaNodeBuildingTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/NewSkip/SingleSchemaNodeBuildingTest.cs
@@ -4,9 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2016.02.24
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Providers;
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/NewSkip/SkipBuildingTestBase.cs b/Orm/Xtensive.Orm.Tests/Upgrade/NewSkip/SkipBuildingTestBase.cs
index 28218dc34..bc3e9a036 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/NewSkip/SkipBuildingTestBase.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/NewSkip/SkipBuildingTestBase.cs
@@ -4,10 +4,7 @@
 // Created by: Alexey Kulakov
 // Created:    2016.02.24
 
-using System;
-using System.Collections.Generic;
 using System.Collections.ObjectModel;
-using System.Linq;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Upgrade;
 using Xtensive.Reflection;
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/NewUpgradeEventsAndPropertiesTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/NewUpgradeEventsAndPropertiesTest.cs
index 97bc5e238..733ad7817 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/NewUpgradeEventsAndPropertiesTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/NewUpgradeEventsAndPropertiesTest.cs
@@ -4,11 +4,7 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.09.28
 
-using System;
-using System.Collections.Generic;
 using System.Data;
-using System.Threading;
-using System.Threading.Tasks;
 using NUnit.Framework;
 using Xtensive.Orm.Tests.Upgrade.NewUpgradeEventsAndPropertiesTestModel;
 using Xtensive.Orm.Upgrade;
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/NodeBasedExtractedModelBuilderTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/NodeBasedExtractedModelBuilderTest.cs
index d39806300..32460b9c7 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/NodeBasedExtractedModelBuilderTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/NodeBasedExtractedModelBuilderTest.cs
@@ -5,7 +5,6 @@
 // Created:    2016.12.13
 
 using System.Text;
-using System.Threading.Tasks;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/NonNullableReferenceRemovalTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/NonNullableReferenceRemovalTest.cs
index b5c7d0ec2..421c18223 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/NonNullableReferenceRemovalTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/NonNullableReferenceRemovalTest.cs
@@ -4,9 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.08.20
 
-using System;
-using System.Collections.Generic;
-using System.Threading.Tasks;
 using NUnit.Framework;
 using Xtensive.Orm.Upgrade;
 using Model1 = Xtensive.Orm.Tests.Upgrade.NonNullableReferenceRemovalTestModel.Model1;
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/PerformSafelyFromEmptyDatabaseTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/PerformSafelyFromEmptyDatabaseTest.cs
index 48023981e..58463f912 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/PerformSafelyFromEmptyDatabaseTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/PerformSafelyFromEmptyDatabaseTest.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.07.05
 
-using System.Threading.Tasks;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Orm.Services;
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/PrimaryKeyModelVersion1.cs b/Orm/Xtensive.Orm.Tests/Upgrade/PrimaryKeyModelVersion1.cs
index dddad28ee..86b1b3bd0 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/PrimaryKeyModelVersion1.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/PrimaryKeyModelVersion1.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2010.02.27
 
-using System;
 using System.Diagnostics;
 
 namespace Xtensive.Orm.Tests.Upgrade.PrimaryKeyModel.Version1
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/PrimaryKeyModelVersion2Perform.cs b/Orm/Xtensive.Orm.Tests/Upgrade/PrimaryKeyModelVersion2Perform.cs
index c6b9046e0..f1b549bb3 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/PrimaryKeyModelVersion2Perform.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/PrimaryKeyModelVersion2Perform.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2010.02.27
 
-using System;
 using System.Diagnostics;
 using Xtensive.Orm.Upgrade;
 
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/PrimaryKeyModelVersion2PerformSafely.cs b/Orm/Xtensive.Orm.Tests/Upgrade/PrimaryKeyModelVersion2PerformSafely.cs
index c8f288c65..55aca267d 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/PrimaryKeyModelVersion2PerformSafely.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/PrimaryKeyModelVersion2PerformSafely.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2010.02.27
 
-using System;
 using System.Diagnostics;
 using Xtensive.Orm.Upgrade;
 
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/PrimaryKeyUpgradeTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/PrimaryKeyUpgradeTest.cs
index cb3d0336f..7d19ecb4b 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/PrimaryKeyUpgradeTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/PrimaryKeyUpgradeTest.cs
@@ -4,8 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2010.02.27
 
-using System;
-using System.Collections.Generic;
 using System.Reflection;
 using NUnit.Framework;
 using Xtensive.Collections;
@@ -14,12 +12,10 @@
 using Xtensive.Orm.Tests.Upgrade.PrimaryKeyModel.Version1;
 using Xtensive.Orm.Tests.Upgrade.PrimaryKeyModel.Version2PerformSafely;
 using Xtensive.Orm.Upgrade;
-using System.Linq;
 using Author = Xtensive.Orm.Tests.Upgrade.PrimaryKeyModel.Version1.Author;
 using Book = Xtensive.Orm.Tests.Upgrade.PrimaryKeyModel.Version1.Book;
 using Author2 = Xtensive.Orm.Tests.Upgrade.PrimaryKeyModel.Version2PerformSafely.Author;
 using Book2 = Xtensive.Orm.Tests.Upgrade.PrimaryKeyModel.Version2PerformSafely.Book;
-using System.Threading.Tasks;
 
 namespace Xtensive.Orm.Tests.Upgrade
 {
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/Recycled/ModelVersion1.cs b/Orm/Xtensive.Orm.Tests/Upgrade/Recycled/ModelVersion1.cs
index 40ff1eff7..8cafdaff8 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/Recycled/ModelVersion1.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/Recycled/ModelVersion1.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.05.20
 
-using System;
 
 namespace Xtensive.Orm.Tests.Upgrade.Recycled.Model.Version1
 {
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/Recycled/ModelVersion2.cs b/Orm/Xtensive.Orm.Tests/Upgrade/Recycled/ModelVersion2.cs
index 0757b9824..810955b99 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/Recycled/ModelVersion2.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/Recycled/ModelVersion2.cs
@@ -5,7 +5,6 @@
 // Created:    2009.05.20
 
 using Xtensive.Orm.Upgrade;
-using System;
 
 namespace Xtensive.Orm.Tests.Upgrade.Recycled.Model.Version2
 {
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/Recycled/RecycledUpgradeTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/Recycled/RecycledUpgradeTest.cs
index 569e56860..c9d6eab88 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/Recycled/RecycledUpgradeTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/Recycled/RecycledUpgradeTest.cs
@@ -4,8 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.05.20
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using System.Reflection;
 
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/Recycled/Upgrader.cs b/Orm/Xtensive.Orm.Tests/Upgrade/Recycled/Upgrader.cs
index 646144f88..6157030ef 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/Recycled/Upgrader.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/Recycled/Upgrader.cs
@@ -4,8 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.05.20
 
-using System;
-using System.Collections.Generic;
 using Xtensive.Core;
 
 using Xtensive.Orm.Upgrade;
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/RecycledDefinitionTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/RecycledDefinitionTest.cs
index a9cb8d69d..3811d2747 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/RecycledDefinitionTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/RecycledDefinitionTest.cs
@@ -4,10 +4,6 @@
 // Created by: Andrey Turkov
 // Created:    2013.08.21
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Threading.Tasks;
 using NUnit.Framework;
 using Xtensive.Orm.Tests.Upgrade.RecycledDefinitionTestModel;
 using Xtensive.Orm.Upgrade;
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/RemoveColumnWithRenameTableTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/RemoveColumnWithRenameTableTest.cs
index 2eaf60d9f..0f198ad98 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/RemoveColumnWithRenameTableTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/RemoveColumnWithRenameTableTest.cs
@@ -4,9 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.07.05
 
-using System;
-using System.Collections.Generic;
-using System.Threading.Tasks;
 using NUnit.Framework;
 using Xtensive.Orm.Upgrade;
 using V1=Xtensive.Orm.Tests.Upgrade.RemoveColumnWithRenameTableTestModel.Version1;
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/Sample3/ModelVersion1.cs b/Orm/Xtensive.Orm.Tests/Upgrade/Sample3/ModelVersion1.cs
index 211931355..9a9d9db65 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/Sample3/ModelVersion1.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/Sample3/ModelVersion1.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.05.20
 
-using System;
 
 namespace Xtensive.Orm.Tests.Upgrade.Sample3.Model.Version1
 {
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/Sample3/ModelVersion2.cs b/Orm/Xtensive.Orm.Tests/Upgrade/Sample3/ModelVersion2.cs
index 669b20d07..599c982a6 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/Sample3/ModelVersion2.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/Sample3/ModelVersion2.cs
@@ -5,11 +5,9 @@
 // Created:    2009.05.20
 
 using System.Collections;
-using System.Linq;
 using Xtensive.Collections;
 using Xtensive.Core;
 using Xtensive.Orm.Upgrade;
-using System;
 
 namespace Xtensive.Orm.Tests.Upgrade.Sample3.Model.Version2
 {
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/Sample3/Sample3UpgradeTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/Sample3/Sample3UpgradeTest.cs
index feca61c76..0128c5a27 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/Sample3/Sample3UpgradeTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/Sample3/Sample3UpgradeTest.cs
@@ -5,7 +5,6 @@
 // Created:    2009.05.20
 
 using System.Collections;
-using System.Linq;
 using NUnit.Framework;
 using System.Reflection;
 using Xtensive.Collections;
@@ -14,7 +13,6 @@
 using Xtensive.Orm.Tests.Upgrade.Sample3.Model.Version2;
 using M1 = Xtensive.Orm.Tests.Upgrade.Sample3.Model.Version1;
 using M2 = Xtensive.Orm.Tests.Upgrade.Sample3.Model.Version2;
-using System;
 
 namespace Xtensive.Orm.Tests.Upgrade.Sample3
 {
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/Sample3/Upgrader.cs b/Orm/Xtensive.Orm.Tests/Upgrade/Sample3/Upgrader.cs
index ab7f92693..9242778a5 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/Sample3/Upgrader.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/Sample3/Upgrader.cs
@@ -4,9 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.05.20
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Core;
 using Xtensive.Collections;
 
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/MakingSchemaExtractionResultSharedTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/MakingSchemaExtractionResultSharedTest.cs
index 5d1e94f53..bf57df305 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/MakingSchemaExtractionResultSharedTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/MakingSchemaExtractionResultSharedTest.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2017.03.02
 
-using System;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Upgrade;
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/MappingResolverTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/MappingResolverTest.cs
index c897c2b2d..50e452c34 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/MappingResolverTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/MappingResolverTest.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2017.03.02
 
-using System.Collections.Generic;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Providers;
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/MetadataUpdate/Model.cs b/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/MetadataUpdate/Model.cs
index 75cb47bef..f715d76bd 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/MetadataUpdate/Model.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/MetadataUpdate/Model.cs
@@ -4,9 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2017.04.03
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Upgrade;
 
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/MetadataUpdate/MultidatabaseTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/MetadataUpdate/MultidatabaseTest.cs
index 9e476e104..0e69fc458 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/MetadataUpdate/MultidatabaseTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/MetadataUpdate/MultidatabaseTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2017.04.03
 
-using System.Collections.Generic;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Providers;
 using model = Xtensive.Orm.Tests.Upgrade.SchemaSharing.MetadataUpdate.Model;
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/MetadataUpdate/MultischemaTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/MetadataUpdate/MultischemaTest.cs
index e61dfde09..214c69b84 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/MetadataUpdate/MultischemaTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/MetadataUpdate/MultischemaTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2017.04.03
 
-using System.Collections.Generic;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Providers;
 using model = Xtensive.Orm.Tests.Upgrade.SchemaSharing.MetadataUpdate.Model;
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/MetadataUpdate/SimpleTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/MetadataUpdate/SimpleTest.cs
index e70e94b15..858c08d62 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/MetadataUpdate/SimpleTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/MetadataUpdate/SimpleTest.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2017.04.03
 
-using System.Collections.Generic;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using model = Xtensive.Orm.Tests.Upgrade.SchemaSharing.MetadataUpdate.Model;
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/Model.cs b/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/Model.cs
index 0b8eb5d26..7fbafc8e8 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/Model.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/Model.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2017.03.02
 
-using System;
 
 namespace Xtensive.Orm.Tests.Upgrade.SchemaSharing.Model
 {
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/QueryBuilder/Model.cs b/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/QueryBuilder/Model.cs
index 10e7e776c..b27557b07 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/QueryBuilder/Model.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/QueryBuilder/Model.cs
@@ -4,9 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2017.03.29
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Upgrade;
 using Xtensive.Sql;
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/QueryBuilder/MultidatabaseTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/QueryBuilder/MultidatabaseTest.cs
index 0a301578a..7794c79d5 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/QueryBuilder/MultidatabaseTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/QueryBuilder/MultidatabaseTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2017.03.30
 
-using System.Collections.Generic;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Providers;
 
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/QueryBuilder/MultischemaTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/QueryBuilder/MultischemaTest.cs
index 9a874257e..b163060eb 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/QueryBuilder/MultischemaTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/QueryBuilder/MultischemaTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2017.03.30
 
-using System.Collections.Generic;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Providers;
 
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/QueryBuilder/SimpleTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/QueryBuilder/SimpleTest.cs
index 17c86aefb..546bcd4f7 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/QueryBuilder/SimpleTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/QueryBuilder/SimpleTest.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2017.03.30
 
-using System.Collections.Generic;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using model = Xtensive.Orm.Tests.Upgrade.SchemaSharing.QueryBuilder.Model;
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/Requests/Model.cs b/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/Requests/Model.cs
index 9885b40f5..ceed58852 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/Requests/Model.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/Requests/Model.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2017.03.29
 
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Upgrade;
 
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/Requests/MultidatabaseTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/Requests/MultidatabaseTest.cs
index 6a94db6b8..2c049a242 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/Requests/MultidatabaseTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/Requests/MultidatabaseTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2017.03.29
 
-using System.Collections.Generic;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Providers;
 using model = Xtensive.Orm.Tests.Upgrade.SchemaSharing.Requests.Model;
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/Requests/MultischemaTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/Requests/MultischemaTest.cs
index e8f589d06..bc9538a0c 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/Requests/MultischemaTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/Requests/MultischemaTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2017.03.29
 
-using System.Collections.Generic;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Providers;
 
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/Requests/SimpleTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/Requests/SimpleTest.cs
index 4dd8ce024..01898eede 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/Requests/SimpleTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/Requests/SimpleTest.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2017.03.29
 
-using System.Collections.Generic;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using model= Xtensive.Orm.Tests.Upgrade.SchemaSharing.Requests.Model;
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/SqlExecutor/Model.cs b/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/SqlExecutor/Model.cs
index 01f54371a..1924daf57 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/SqlExecutor/Model.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/SqlExecutor/Model.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2017.03.28
 
-using System;
-using System.Collections.Generic;
 using NUnit.Framework;
 using Xtensive.Orm.Providers;
 using Xtensive.Orm.Upgrade;
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/SqlExecutor/MultidatabaseTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/SqlExecutor/MultidatabaseTest.cs
index 082d6be2a..220a672cb 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/SqlExecutor/MultidatabaseTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/SqlExecutor/MultidatabaseTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2017.03.28
 
-using System.Collections.Generic;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Providers;
 using model = Xtensive.Orm.Tests.Upgrade.SchemaSharing.SqlExecutor.Model;
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/SqlExecutor/MultischemaTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/SqlExecutor/MultischemaTest.cs
index b79cec09d..a62d4efa1 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/SqlExecutor/MultischemaTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/SqlExecutor/MultischemaTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2017.03.28
 
-using System.Collections.Generic;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Providers;
 using model = Xtensive.Orm.Tests.Upgrade.SchemaSharing.SqlExecutor.Model;
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/SqlExecutor/SimpleTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/SqlExecutor/SimpleTest.cs
index 4a0a36a2a..e482c6c63 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/SqlExecutor/SimpleTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/SqlExecutor/SimpleTest.cs
@@ -4,9 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2017.03.28
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using model = Xtensive.Orm.Tests.Upgrade.SchemaSharing.SqlExecutor.Model;
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/StorageNodeBuildingTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/StorageNodeBuildingTest.cs
index b0ac8be29..b9cdf01d7 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/StorageNodeBuildingTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/StorageNodeBuildingTest.cs
@@ -4,9 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2017.03.03
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Providers;
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/TemporaryTableManager/MultischemaTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/TemporaryTableManager/MultischemaTest.cs
index f185934f3..236655a02 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/TemporaryTableManager/MultischemaTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/TemporaryTableManager/MultischemaTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2017.03.03
 
-using System.Collections.Generic;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Providers;
 using model = Xtensive.Orm.Tests.Upgrade.SchemaSharing.TemporaryTableManager.Model;
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/TemporaryTableManager/SimpleTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/TemporaryTableManager/SimpleTest.cs
index c24d28449..f9e7f315d 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/TemporaryTableManager/SimpleTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/SchemaSharing/TemporaryTableManager/SimpleTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2017.03.03
 
-using System.Collections.Generic;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using model = Xtensive.Orm.Tests.Upgrade.SchemaSharing.TemporaryTableManager.Model;
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/SimpleModelVersion1.cs b/Orm/Xtensive.Orm.Tests/Upgrade/SimpleModelVersion1.cs
index 681cb5cfb..ffd9e8909 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/SimpleModelVersion1.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/SimpleModelVersion1.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2010.01.15
 
-using System;
 using System.Diagnostics;
 
 namespace Xtensive.Orm.Tests.Upgrade.Model.SimpleVersion1
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/SimpleModelVersion2.cs b/Orm/Xtensive.Orm.Tests/Upgrade/SimpleModelVersion2.cs
index 43c6ff633..6e9d3a01e 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/SimpleModelVersion2.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/SimpleModelVersion2.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2010.01.15
 
-using System;
 using System.Diagnostics;
 
 namespace Xtensive.Orm.Tests.Upgrade.Model.SimpleVersion2
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/SimpleUpgrader.cs b/Orm/Xtensive.Orm.Tests/Upgrade/SimpleUpgrader.cs
index 9cd472ab4..096e7f82f 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/SimpleUpgrader.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/SimpleUpgrader.cs
@@ -4,8 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2010.01.15
 
-using System;
-using System.Collections.Generic;
 using Xtensive.Core;
 
 using Xtensive.Orm.Tests.Upgrade.Model.SimpleVersion2;
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/SkipUpgradeTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/SkipUpgradeTest.cs
index 0653f68c8..d0cbc5e78 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/SkipUpgradeTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/SkipUpgradeTest.cs
@@ -4,12 +4,8 @@
 // Created by: Denis Krjuchkov
 // Created:    2010.03.05
 
-using System;
-using System.Collections.Generic;
 using NUnit.Framework;
-using System.Linq;
 using Xtensive.Orm.Tests.Upgrade.SkipUpgradeTestModel;
-using System.Threading.Tasks;
 
 namespace Xtensive.Orm.Tests.Upgrade.SkipUpgradeTestModel
 {
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/SplitHierarchyTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/SplitHierarchyTest.cs
index d7f66ab83..c21047ab5 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/SplitHierarchyTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/SplitHierarchyTest.cs
@@ -4,10 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.09.19
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Threading.Tasks;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Upgrade;
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/SqlWorkerAndSqlAsyncWorkerTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/SqlWorkerAndSqlAsyncWorkerTest.cs
index 54f776c98..565f0c023 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/SqlWorkerAndSqlAsyncWorkerTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/SqlWorkerAndSqlAsyncWorkerTest.cs
@@ -4,12 +4,7 @@
 // Created by: Julian Mamokin
 // Created:    2017.03.01
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Reflection;
-using System.Threading;
-using System.Threading.Tasks;
 using NUnit.Framework;
 using Xtensive.Core;
 using Xtensive.Orm.Building.Builders;
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/TypeConversionVerifierTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/TypeConversionVerifierTest.cs
index e5cb08fb1..b4a43196a 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/TypeConversionVerifierTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/TypeConversionVerifierTest.cs
@@ -4,9 +4,6 @@
 // Created by: Alexander Nikolaev
 // Created:    2009.05.29
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Upgrade.Model;
 using Xtensive.Orm.Upgrade;
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/TypeIdPreserveTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/TypeIdPreserveTest.cs
index b045663fe..bbe4babac 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/TypeIdPreserveTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/TypeIdPreserveTest.cs
@@ -4,10 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2014.03.01
 
-using System;
-using System.Linq;
-using System.Threading;
-using System.Threading.Tasks;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Upgrade;
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/TypeIdUpgrade/Many2SingleClassTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/TypeIdUpgrade/Many2SingleClassTest.cs
index d7fbdf5c7..3068445e1 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/TypeIdUpgrade/Many2SingleClassTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/TypeIdUpgrade/Many2SingleClassTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.12.29
 
-using System.Linq;
 using NUnit.Framework;
 
 namespace Xtensive.Orm.Tests.Upgrade.TypeIdUpgrade
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/TypeIdUpgrade/Model.cs b/Orm/Xtensive.Orm.Tests/Upgrade/TypeIdUpgrade/Model.cs
index e191a5cc2..140b621e6 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/TypeIdUpgrade/Model.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/TypeIdUpgrade/Model.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.12.28
 
-using System;
 using System.Diagnostics;
 
 namespace Xtensive.Orm.Tests.Upgrade.TypeIdUpgrade.Model
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/TypeIdUpgrade/Single2ManyClassesTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/TypeIdUpgrade/Single2ManyClassesTest.cs
index 82b57315c..df1029e65 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/TypeIdUpgrade/Single2ManyClassesTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/TypeIdUpgrade/Single2ManyClassesTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.12.28
 
-using System.Linq;
 using NUnit.Framework;
 
 namespace Xtensive.Orm.Tests.Upgrade.TypeIdUpgrade
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/TypeIdUpgrade/Upgrader.cs b/Orm/Xtensive.Orm.Tests/Upgrade/TypeIdUpgrade/Upgrader.cs
index ed727dd18..2630b5a92 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/TypeIdUpgrade/Upgrader.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/TypeIdUpgrade/Upgrader.cs
@@ -4,8 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.12.29
 
-using System;
-using System.Collections.Generic;
 using Xtensive.Core;
 using Xtensive.Orm.Upgrade;
 
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/TypeIdUpgrade/VersionUpgradeTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/TypeIdUpgrade/VersionUpgradeTest.cs
index fd8b40807..47e33e11b 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/TypeIdUpgrade/VersionUpgradeTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/TypeIdUpgrade/VersionUpgradeTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.12.29
 
-using System.Linq;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Providers;
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeAndNamingRules/ModelVersion1.cs b/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeAndNamingRules/ModelVersion1.cs
index ca165f974..3a703b262 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeAndNamingRules/ModelVersion1.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeAndNamingRules/ModelVersion1.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.05.20
 
-using System;
 
 namespace Xtensive.Orm.Tests.Upgrade.UpgradeAndNamingRules.Model.Version1
 {
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeAndNamingRules/ModelVersion2.cs b/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeAndNamingRules/ModelVersion2.cs
index 7b748f320..c86a5d602 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeAndNamingRules/ModelVersion2.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeAndNamingRules/ModelVersion2.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.05.20
 
-using System;
 
 namespace Xtensive.Orm.Tests.Upgrade.UpgradeAndNamingRules.Model.Version2
 {
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeAndNamingRules/UpgradeTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeAndNamingRules/UpgradeTest.cs
index 62f13f6c0..86b8e9d57 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeAndNamingRules/UpgradeTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeAndNamingRules/UpgradeTest.cs
@@ -4,8 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.05.20
 
-using System;
-using System.Linq;
 using System.Reflection;
 using Xtensive.Core;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeAndNamingRules/Upgrader.cs b/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeAndNamingRules/Upgrader.cs
index fba35f675..4e491507d 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeAndNamingRules/Upgrader.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeAndNamingRules/Upgrader.cs
@@ -4,9 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.05.20
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Core;
 
 using Xtensive.Orm.Upgrade;
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeAndNamingRulesAdvanced/RemoveDotsAndHyphensRule.cs b/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeAndNamingRulesAdvanced/RemoveDotsAndHyphensRule.cs
index b9c91e2d9..b43a3abfa 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeAndNamingRulesAdvanced/RemoveDotsAndHyphensRule.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeAndNamingRulesAdvanced/RemoveDotsAndHyphensRule.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2016.02.05
 
-using System.Collections.Generic;
 using Xtensive.Orm.Configuration;
 
 namespace Xtensive.Orm.Tests.Upgrade.UpgradeAndNamingRulesAdvanced
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeAndNamingRulesAdvanced/RemoveDotsRuleTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeAndNamingRulesAdvanced/RemoveDotsRuleTest.cs
index 22c6c3792..763184ec8 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeAndNamingRulesAdvanced/RemoveDotsRuleTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeAndNamingRulesAdvanced/RemoveDotsRuleTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2016.02.05
 
-using System.Collections.Generic;
 using Xtensive.Orm.Configuration;
 
 namespace Xtensive.Orm.Tests.Upgrade.UpgradeAndNamingRulesAdvanced
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeAndNamingRulesAdvanced/RemoveHyphensRuleTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeAndNamingRulesAdvanced/RemoveHyphensRuleTest.cs
index 472e75b5b..1b7f3d19e 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeAndNamingRulesAdvanced/RemoveHyphensRuleTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeAndNamingRulesAdvanced/RemoveHyphensRuleTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2016.02.05
 
-using System.Collections.Generic;
 using Xtensive.Orm.Configuration;
 
 namespace Xtensive.Orm.Tests.Upgrade.UpgradeAndNamingRulesAdvanced
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeAndNamingRulesAdvanced/SynonymsOfNamespacesTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeAndNamingRulesAdvanced/SynonymsOfNamespacesTest.cs
index 915166d9f..3fa5d2f2f 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeAndNamingRulesAdvanced/SynonymsOfNamespacesTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeAndNamingRulesAdvanced/SynonymsOfNamespacesTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2016.02.05
 
-using System.Collections.Generic;
 using Xtensive.Orm.Configuration;
 
 namespace Xtensive.Orm.Tests.Upgrade.UpgradeAndNamingRulesAdvanced
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeAndNamingRulesAdvanced/TargetModels.cs b/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeAndNamingRulesAdvanced/TargetModels.cs
index be31b38a2..d958bb9e5 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeAndNamingRulesAdvanced/TargetModels.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeAndNamingRulesAdvanced/TargetModels.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2016.02.03
 
-using System.Collections.Generic;
 using Xtensive.Orm.Model;
 using Xtensive.Orm.Upgrade;
 
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeAndNamingRulesAdvanced/TestBase.cs b/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeAndNamingRulesAdvanced/TestBase.cs
index d12c2cbd0..54c3cc739 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeAndNamingRulesAdvanced/TestBase.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeAndNamingRulesAdvanced/TestBase.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2016.02.03
 
-using System;
-using System.Linq;
 using System.Reflection;
 using NUnit.Framework;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeAndNamingRulesAdvanced/UnderscoreDotsAndHyphensRule.cs b/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeAndNamingRulesAdvanced/UnderscoreDotsAndHyphensRule.cs
index 4152b0a64..253ce6d14 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeAndNamingRulesAdvanced/UnderscoreDotsAndHyphensRule.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeAndNamingRulesAdvanced/UnderscoreDotsAndHyphensRule.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2016.02.05
 
-using System.Collections.Generic;
 using Xtensive.Orm.Configuration;
 
 namespace Xtensive.Orm.Tests.Upgrade.UpgradeAndNamingRulesAdvanced
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeAndNamingRulesAdvanced/UnderscoreDotsRuleTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeAndNamingRulesAdvanced/UnderscoreDotsRuleTest.cs
index 4c10c64b6..bb02bf60c 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeAndNamingRulesAdvanced/UnderscoreDotsRuleTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeAndNamingRulesAdvanced/UnderscoreDotsRuleTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2016.02.05
 
-using System.Collections.Generic;
 using Xtensive.Orm.Configuration;
 
 namespace Xtensive.Orm.Tests.Upgrade.UpgradeAndNamingRulesAdvanced
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeAndNamingRulesAdvanced/UnderscoreHyphensRuleTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeAndNamingRulesAdvanced/UnderscoreHyphensRuleTest.cs
index db1028175..c920d271f 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeAndNamingRulesAdvanced/UnderscoreHyphensRuleTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeAndNamingRulesAdvanced/UnderscoreHyphensRuleTest.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2016.02.05
 
-using System.Collections.Generic;
 using Xtensive.Orm.Configuration;
 
 namespace Xtensive.Orm.Tests.Upgrade.UpgradeAndNamingRulesAdvanced
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeContextTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeContextTest.cs
index b31f0f00c..534702e91 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeContextTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeContextTest.cs
@@ -4,12 +4,7 @@
 // Created by: Alexey Kulakov
 // Created:    2018.09.27
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Reflection;
-using System.Threading;
-using System.Threading.Tasks;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Providers;
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeDateTimeOffsetTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeDateTimeOffsetTest.cs
index 50b2ba78c..2d7aa9dcd 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeDateTimeOffsetTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeDateTimeOffsetTest.cs
@@ -4,10 +4,6 @@
 // Created by: Alena Mikshina
 // Created:    2014.02.06
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Threading.Tasks;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Providers;
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeSchemaWithNonDOSequences.cs b/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeSchemaWithNonDOSequences.cs
index 7e9bbcb67..7ad85c539 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeSchemaWithNonDOSequences.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeSchemaWithNonDOSequences.cs
@@ -2,7 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Services;
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeTestTemplate.cs b/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeTestTemplate.cs
index ba256e062..dbd1eefd5 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeTestTemplate.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeTestTemplate.cs
@@ -4,9 +4,6 @@
 // Created by: <AUTHOR>
 // Created:    <YYYY.MM.DD>
 
-using System;
-using System.Collections.Generic;
-using System.Threading.Tasks;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Upgrade;
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeToStructure/ModelVersion1.cs b/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeToStructure/ModelVersion1.cs
index ae8ea5a4d..da9aa8ff0 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeToStructure/ModelVersion1.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeToStructure/ModelVersion1.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.05.20
 
-using System;
 
 namespace Xtensive.Orm.Tests.Upgrade.UpgradeToStructure.Model.Version1
 {
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeToStructure/ModelVersion2.cs b/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeToStructure/ModelVersion2.cs
index 54207118b..d2b925732 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeToStructure/ModelVersion2.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeToStructure/ModelVersion2.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.05.20
 
-using System;
 
 namespace Xtensive.Orm.Tests.Upgrade.UpgradeToStructure.Model.Version2
 {
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeToStructure/UpgradeTest.cs b/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeToStructure/UpgradeTest.cs
index 09f8d7c12..dea968dce 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeToStructure/UpgradeTest.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeToStructure/UpgradeTest.cs
@@ -4,8 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.05.20
 
-using System;
-using System.Linq;
 using System.Reflection;
 using Xtensive.Core;
 using M1 = Xtensive.Orm.Tests.Upgrade.UpgradeToStructure.Model.Version1;
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeToStructure/Upgrader.cs b/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeToStructure/Upgrader.cs
index 965e849ce..906eb0a09 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeToStructure/Upgrader.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/UpgradeToStructure/Upgrader.cs
@@ -4,9 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.05.20
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Core;
 
 using Xtensive.Orm.Upgrade;
diff --git a/Orm/Xtensive.Orm.Tests/Upgrade/Upgrader.cs b/Orm/Xtensive.Orm.Tests/Upgrade/Upgrader.cs
index 55e7258d4..6aaf877c9 100644
--- a/Orm/Xtensive.Orm.Tests/Upgrade/Upgrader.cs
+++ b/Orm/Xtensive.Orm.Tests/Upgrade/Upgrader.cs
@@ -4,8 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.05.20
 
-using System;
-using System.Collections.Generic;
 using Xtensive.Core;
 
 using Xtensive.Orm.Tests.Upgrade.Model.Version2;
diff --git a/Orm/Xtensive.Orm.Tests/_Manual/Validation/Person.cs b/Orm/Xtensive.Orm.Tests/_Manual/Validation/Person.cs
index 937d29ada..e0923c13e 100644
--- a/Orm/Xtensive.Orm.Tests/_Manual/Validation/Person.cs
+++ b/Orm/Xtensive.Orm.Tests/_Manual/Validation/Person.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Kofman
 // Created:    2009.10.27
 
-using System;
 using Xtensive.Orm.Tests._Manual.Validation;
 using Xtensive.Orm.Validation;
 
diff --git a/Orm/Xtensive.Orm.Tests/_Manual/Validation/PhoneNumberConstraint.cs b/Orm/Xtensive.Orm.Tests/_Manual/Validation/PhoneNumberConstraint.cs
index affab2c77..65324bb5b 100644
--- a/Orm/Xtensive.Orm.Tests/_Manual/Validation/PhoneNumberConstraint.cs
+++ b/Orm/Xtensive.Orm.Tests/_Manual/Validation/PhoneNumberConstraint.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Kofman
 // Created:    2009.10.28
 
-using System;
 using System.Text.RegularExpressions;
 using Xtensive.Orm.Model;
 using Xtensive.Orm.Validation;
diff --git a/Orm/Xtensive.Orm.Tests/_Manual/Validation/TestFixture.cs b/Orm/Xtensive.Orm.Tests/_Manual/Validation/TestFixture.cs
index 0bb73d83e..002534fdb 100644
--- a/Orm/Xtensive.Orm.Tests/_Manual/Validation/TestFixture.cs
+++ b/Orm/Xtensive.Orm.Tests/_Manual/Validation/TestFixture.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Kofman
 // Created:    2009.10.28
 
-using System;
 using NUnit.Framework;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Validation;
diff --git a/Orm/Xtensive.Orm/Annotations.cs b/Orm/Xtensive.Orm/Annotations.cs
index 234591ee7..af9a62f87 100644
--- a/Orm/Xtensive.Orm/Annotations.cs
+++ b/Orm/Xtensive.Orm/Annotations.cs
@@ -14,7 +14,6 @@
  * limitations under the License.
  */
 
-using System;
 
 // ReSharper disable CheckNamespace
 namespace JetBrains.Annotations
diff --git a/Orm/Xtensive.Orm/Arithmetic/Arithmetic.cs b/Orm/Xtensive.Orm/Arithmetic/Arithmetic.cs
index dae2b7b2b..5b55b77e6 100644
--- a/Orm/Xtensive.Orm/Arithmetic/Arithmetic.cs
+++ b/Orm/Xtensive.Orm/Arithmetic/Arithmetic.cs
@@ -4,10 +4,8 @@
 // Created by: Alexey Gamzov
 // Created:    2008.02.12
 
-using System;
 using System.Diagnostics;
 using System.Runtime.Serialization;
-using System.Threading;
 using Xtensive.Core;
 
 
diff --git a/Orm/Xtensive.Orm/Arithmetic/ArithmeticBase.cs b/Orm/Xtensive.Orm/Arithmetic/ArithmeticBase.cs
index 22819604e..9ef3f27fc 100644
--- a/Orm/Xtensive.Orm/Arithmetic/ArithmeticBase.cs
+++ b/Orm/Xtensive.Orm/Arithmetic/ArithmeticBase.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.02.06
 
-using System;
 using System.Collections.Concurrent;
 using System.Diagnostics;
 using System.Runtime.Serialization;
diff --git a/Orm/Xtensive.Orm/Arithmetic/ArithmeticProvider.cs b/Orm/Xtensive.Orm/Arithmetic/ArithmeticProvider.cs
index a862dff99..780fe1b22 100644
--- a/Orm/Xtensive.Orm/Arithmetic/ArithmeticProvider.cs
+++ b/Orm/Xtensive.Orm/Arithmetic/ArithmeticProvider.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2008.01.22
 
-using System;
 using System.Diagnostics;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Arithmetic/ArithmeticRules.cs b/Orm/Xtensive.Orm/Arithmetic/ArithmeticRules.cs
index 020f3759c..85162ab6d 100644
--- a/Orm/Xtensive.Orm/Arithmetic/ArithmeticRules.cs
+++ b/Orm/Xtensive.Orm/Arithmetic/ArithmeticRules.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2008.02.10
 
-using System;
 
 namespace Xtensive.Arithmetic
 {
diff --git a/Orm/Xtensive.Orm/Arithmetic/ArithmeticStruct.cs b/Orm/Xtensive.Orm/Arithmetic/ArithmeticStruct.cs
index c28d00273..cc738a9cc 100644
--- a/Orm/Xtensive.Orm/Arithmetic/ArithmeticStruct.cs
+++ b/Orm/Xtensive.Orm/Arithmetic/ArithmeticStruct.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2008.02.12
 
-using System;
 using System.Runtime.Serialization;
 using System.Security;
 using System.Security.Permissions;
diff --git a/Orm/Xtensive.Orm/Arithmetic/Internal/NullableArithmetic.cs b/Orm/Xtensive.Orm/Arithmetic/Internal/NullableArithmetic.cs
index 7e7e93c83..18a9ff940 100644
--- a/Orm/Xtensive.Orm/Arithmetic/Internal/NullableArithmetic.cs
+++ b/Orm/Xtensive.Orm/Arithmetic/Internal/NullableArithmetic.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.02.06
 
-using System;
 
 
 namespace Xtensive.Arithmetic
diff --git a/Orm/Xtensive.Orm/Arithmetic/Internal/PrimitiveArithmetics.cs b/Orm/Xtensive.Orm/Arithmetic/Internal/PrimitiveArithmetics.cs
index e14f4c694..5ed36d8ef 100644
--- a/Orm/Xtensive.Orm/Arithmetic/Internal/PrimitiveArithmetics.cs
+++ b/Orm/Xtensive.Orm/Arithmetic/Internal/PrimitiveArithmetics.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2008.01.22
 
-using System;
 using Xtensive.Arithmetic;
 
 
diff --git a/Orm/Xtensive.Orm/Arithmetic/NullBehavior.cs b/Orm/Xtensive.Orm/Arithmetic/NullBehavior.cs
index 95bd2f354..4e46069a4 100644
--- a/Orm/Xtensive.Orm/Arithmetic/NullBehavior.cs
+++ b/Orm/Xtensive.Orm/Arithmetic/NullBehavior.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2008.02.10
 
-using System;
 
 namespace Xtensive.Arithmetic
 {
diff --git a/Orm/Xtensive.Orm/Arithmetic/OverflowBehavior.cs b/Orm/Xtensive.Orm/Arithmetic/OverflowBehavior.cs
index 0b9aa67e3..4ce10e7cd 100644
--- a/Orm/Xtensive.Orm/Arithmetic/OverflowBehavior.cs
+++ b/Orm/Xtensive.Orm/Arithmetic/OverflowBehavior.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2008.02.10
 
-using System;
 
 namespace Xtensive.Arithmetic
 {
diff --git a/Orm/Xtensive.Orm/Arithmetic/WrappingArithmetic{T,TBase}.cs b/Orm/Xtensive.Orm/Arithmetic/WrappingArithmetic{T,TBase}.cs
index 3aee2b519..41fd99d1d 100644
--- a/Orm/Xtensive.Orm/Arithmetic/WrappingArithmetic{T,TBase}.cs
+++ b/Orm/Xtensive.Orm/Arithmetic/WrappingArithmetic{T,TBase}.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.02.06
 
-using System;
 using Xtensive.Core;
 
 
diff --git a/Orm/Xtensive.Orm/Caching/CacheBase.cs b/Orm/Xtensive.Orm/Caching/CacheBase.cs
index bdcc5f7d4..f99f658aa 100755
--- a/Orm/Xtensive.Orm/Caching/CacheBase.cs
+++ b/Orm/Xtensive.Orm/Caching/CacheBase.cs
@@ -2,9 +2,7 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
 using System.Diagnostics;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Caching/FastConcurrentLruCache{TKey, TItem}.cs b/Orm/Xtensive.Orm/Caching/FastConcurrentLruCache{TKey, TItem}.cs
index 5fcd8e86b..1be107b2f 100755
--- a/Orm/Xtensive.Orm/Caching/FastConcurrentLruCache{TKey, TItem}.cs	
+++ b/Orm/Xtensive.Orm/Caching/FastConcurrentLruCache{TKey, TItem}.cs	
@@ -2,8 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Collections.Generic;
 using BitFaster.Caching.Lru;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Caching/InfiniteCache.cs b/Orm/Xtensive.Orm/Caching/InfiniteCache.cs
index d44904cf1..5aded8420 100644
--- a/Orm/Xtensive.Orm/Caching/InfiniteCache.cs
+++ b/Orm/Xtensive.Orm/Caching/InfiniteCache.cs
@@ -4,9 +4,7 @@
 // Created by: Ivan Galkin
 // Created:    2009.03.11
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
 using Xtensive.Collections;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Caching/Interfaces/ICache.cs b/Orm/Xtensive.Orm/Caching/Interfaces/ICache.cs
index d9aa76a80..61d3e7cd7 100644
--- a/Orm/Xtensive.Orm/Caching/Interfaces/ICache.cs
+++ b/Orm/Xtensive.Orm/Caching/Interfaces/ICache.cs
@@ -4,9 +4,7 @@
 // Created by: Alex Yakunin
 // Created:    2007.05.25
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
 using System.Diagnostics;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Caching/LruCache{TKey, TItem, TCached}.cs b/Orm/Xtensive.Orm/Caching/LruCache{TKey, TItem, TCached}.cs
index 4ab9bd12b..a9519c0c6 100644
--- a/Orm/Xtensive.Orm/Caching/LruCache{TKey, TItem, TCached}.cs	
+++ b/Orm/Xtensive.Orm/Caching/LruCache{TKey, TItem, TCached}.cs	
@@ -4,9 +4,7 @@
 // Created by: Alex Ustinov
 // Created:    2007.05.28
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
 using System.Diagnostics;
 using Xtensive.Collections;
 using Xtensive.Conversion;
diff --git a/Orm/Xtensive.Orm/Caching/LruCache{TKey, TItem}.cs b/Orm/Xtensive.Orm/Caching/LruCache{TKey, TItem}.cs
index a0e06a916..5b935ba36 100644
--- a/Orm/Xtensive.Orm/Caching/LruCache{TKey, TItem}.cs	
+++ b/Orm/Xtensive.Orm/Caching/LruCache{TKey, TItem}.cs	
@@ -4,9 +4,7 @@
 // Created by: Alex Ustinov
 // Created:    2007.05.28
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
 using System.Diagnostics;
 using Xtensive.Collections;
 using Xtensive.Conversion;
diff --git a/Orm/Xtensive.Orm/Caching/MfLruCache.cs b/Orm/Xtensive.Orm/Caching/MfLruCache.cs
index c220da06f..90b1d5a58 100644
--- a/Orm/Xtensive.Orm/Caching/MfLruCache.cs
+++ b/Orm/Xtensive.Orm/Caching/MfLruCache.cs
@@ -4,9 +4,7 @@
 // Created by: Alex Ustinov
 // Created:    2007.05.28
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
 using System.Diagnostics;
 using Xtensive.Collections;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Caching/WeakCache.cs b/Orm/Xtensive.Orm/Caching/WeakCache.cs
index 0f4596956..cf8b1b803 100644
--- a/Orm/Xtensive.Orm/Caching/WeakCache.cs
+++ b/Orm/Xtensive.Orm/Caching/WeakCache.cs
@@ -4,11 +4,8 @@
 // Created by: Alex Ustinov
 // Created:    2007.05.28
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
 using System.Diagnostics;
-using System.Linq;
 using System.Runtime.InteropServices;
 using System.Security;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Caching/WeakestCache.cs b/Orm/Xtensive.Orm/Caching/WeakestCache.cs
index f544c1649..cc0015f89 100644
--- a/Orm/Xtensive.Orm/Caching/WeakestCache.cs
+++ b/Orm/Xtensive.Orm/Caching/WeakestCache.cs
@@ -4,9 +4,7 @@
 // Created by: Alex Ustinov
 // Created:    2007.05.28
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
 using System.Diagnostics;
 using System.Runtime.InteropServices;
 using System.Security;
diff --git a/Orm/Xtensive.Orm/Collections/BindingCollection.cs b/Orm/Xtensive.Orm/Collections/BindingCollection.cs
index de594dbe0..e73d76b76 100644
--- a/Orm/Xtensive.Orm/Collections/BindingCollection.cs
+++ b/Orm/Xtensive.Orm/Collections/BindingCollection.cs
@@ -4,9 +4,7 @@
 // Created by: Alexis Kochetov
 // Created:    2009.03.12
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
 using System.Diagnostics;
 
 
diff --git a/Orm/Xtensive.Orm/Collections/ChainedBuffer.cs b/Orm/Xtensive.Orm/Collections/ChainedBuffer.cs
index fffd5b397..b08c8c959 100644
--- a/Orm/Xtensive.Orm/Collections/ChainedBuffer.cs
+++ b/Orm/Xtensive.Orm/Collections/ChainedBuffer.cs
@@ -4,11 +4,8 @@
 // Created by: Alena Mikshina
 // Created:    2013.08.19
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
 using Xtensive.Core;
-using System.Linq;
 
 namespace Xtensive.Collections
 {
diff --git a/Orm/Xtensive.Orm/Collections/ChangeNotifierEventArgs.cs b/Orm/Xtensive.Orm/Collections/ChangeNotifierEventArgs.cs
index 43a2f109d..f4a8a9cf9 100644
--- a/Orm/Xtensive.Orm/Collections/ChangeNotifierEventArgs.cs
+++ b/Orm/Xtensive.Orm/Collections/ChangeNotifierEventArgs.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2007.10.15
 
-using System;
 
 
 namespace Xtensive.Collections
diff --git a/Orm/Xtensive.Orm/Collections/ClassifiedCollection.cs b/Orm/Xtensive.Orm/Collections/ClassifiedCollection.cs
index 38688ca65..5774f4caf 100644
--- a/Orm/Xtensive.Orm/Collections/ClassifiedCollection.cs
+++ b/Orm/Xtensive.Orm/Collections/ClassifiedCollection.cs
@@ -4,11 +4,8 @@
 // Created by: Alex Yakunin
 // Created:    2010.07.02
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
 using System.Diagnostics;
-using System.Linq;
 
 namespace Xtensive.Collections
 {
diff --git a/Orm/Xtensive.Orm/Collections/CollectionBaseSlim.cs b/Orm/Xtensive.Orm/Collections/CollectionBaseSlim.cs
index 46f2e5922..845e90b34 100644
--- a/Orm/Xtensive.Orm/Collections/CollectionBaseSlim.cs
+++ b/Orm/Xtensive.Orm/Collections/CollectionBaseSlim.cs
@@ -4,9 +4,7 @@
 // Created by: Alexey Kochetov
 // Created:    2007.09.24
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
 using System.Diagnostics;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Collections/CollectionUtils.cs b/Orm/Xtensive.Orm/Collections/CollectionUtils.cs
index aa47715dc..8035a187d 100644
--- a/Orm/Xtensive.Orm/Collections/CollectionUtils.cs
+++ b/Orm/Xtensive.Orm/Collections/CollectionUtils.cs
@@ -4,10 +4,7 @@
 // Created by: Denis Kudelin
 // Created:    2019.03.21
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Core;
 
 namespace Xtensive.Collections
diff --git a/Orm/Xtensive.Orm/Collections/Deque.cs b/Orm/Xtensive.Orm/Collections/Deque.cs
index 2de039b41..bf225df52 100644
--- a/Orm/Xtensive.Orm/Collections/Deque.cs
+++ b/Orm/Xtensive.Orm/Collections/Deque.cs
@@ -2,9 +2,7 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
 using System.Diagnostics;
 using System.Runtime.Serialization;
 using System.Security;
diff --git a/Orm/Xtensive.Orm/Collections/DirectionCollection.cs b/Orm/Xtensive.Orm/Collections/DirectionCollection.cs
index 61117ee63..cf9108c22 100644
--- a/Orm/Xtensive.Orm/Collections/DirectionCollection.cs
+++ b/Orm/Xtensive.Orm/Collections/DirectionCollection.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Kochetov
 // Created:    2007.09.24
 
-using System;
-using System.Collections.Generic;
 using System.Diagnostics;
 using Xtensive.Conversion;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Collections/EnumerableUtils.cs b/Orm/Xtensive.Orm/Collections/EnumerableUtils.cs
index 86219ddf9..81b7779d1 100644
--- a/Orm/Xtensive.Orm/Collections/EnumerableUtils.cs
+++ b/Orm/Xtensive.Orm/Collections/EnumerableUtils.cs
@@ -4,9 +4,7 @@
 // Created by: Alex Yakunin
 // Created:    2008.07.04
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
 using Xtensive.Core;
 
 namespace Xtensive.Collections
diff --git a/Orm/Xtensive.Orm/Collections/ExtensionCollection.cs b/Orm/Xtensive.Orm/Collections/ExtensionCollection.cs
index fe851865d..d34c7cd4f 100644
--- a/Orm/Xtensive.Orm/Collections/ExtensionCollection.cs
+++ b/Orm/Xtensive.Orm/Collections/ExtensionCollection.cs
@@ -4,11 +4,8 @@
 // Created by: Alex Yakunin
 // Created:    2008.07.03
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
 using System.Diagnostics;
-using System.Linq;
 using Xtensive.Core;
 using Xtensive.Reflection;
 
diff --git a/Orm/Xtensive.Orm/Collections/FixedList3.cs b/Orm/Xtensive.Orm/Collections/FixedList3.cs
index c7a0539ca..d9c16fab7 100644
--- a/Orm/Xtensive.Orm/Collections/FixedList3.cs
+++ b/Orm/Xtensive.Orm/Collections/FixedList3.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Kochetov
 // Created:    2007.10.20
 
-using System;
-using System.Collections.Generic;
 using System.Diagnostics;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Collections/FlagCollection.cs b/Orm/Xtensive.Orm/Collections/FlagCollection.cs
index 4c0948f4d..d8460780c 100644
--- a/Orm/Xtensive.Orm/Collections/FlagCollection.cs
+++ b/Orm/Xtensive.Orm/Collections/FlagCollection.cs
@@ -4,9 +4,7 @@
 // Created by: Alexey Kochetov
 // Created:    2007.10.01
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
 using System.Collections.ObjectModel;
 using System.Collections.Specialized;
 using System.Diagnostics;
diff --git a/Orm/Xtensive.Orm/Collections/Graphs/Edge.cs b/Orm/Xtensive.Orm/Collections/Graphs/Edge.cs
index dea53bd5b..73c3f6518 100644
--- a/Orm/Xtensive.Orm/Collections/Graphs/Edge.cs
+++ b/Orm/Xtensive.Orm/Collections/Graphs/Edge.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2012.02.22
 
-using System;
 using Xtensive.Core;
 
 
diff --git a/Orm/Xtensive.Orm/Collections/Graphs/Edge{TValue}.cs b/Orm/Xtensive.Orm/Collections/Graphs/Edge{TValue}.cs
index 8016c23ef..7d02aef2b 100644
--- a/Orm/Xtensive.Orm/Collections/Graphs/Edge{TValue}.cs
+++ b/Orm/Xtensive.Orm/Collections/Graphs/Edge{TValue}.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2012.02.22
 
-using System;
 
 
 namespace Xtensive.Collections.Graphs
diff --git a/Orm/Xtensive.Orm/Collections/Graphs/Graph.cs b/Orm/Xtensive.Orm/Collections/Graphs/Graph.cs
index 4d476f797..9b9424349 100644
--- a/Orm/Xtensive.Orm/Collections/Graphs/Graph.cs
+++ b/Orm/Xtensive.Orm/Collections/Graphs/Graph.cs
@@ -4,9 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2012.02.22
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Core;
 
 
diff --git a/Orm/Xtensive.Orm/Collections/Graphs/Node.cs b/Orm/Xtensive.Orm/Collections/Graphs/Node.cs
index f5fab8e38..3187d5197 100644
--- a/Orm/Xtensive.Orm/Collections/Graphs/Node.cs
+++ b/Orm/Xtensive.Orm/Collections/Graphs/Node.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2012.02.22
 
-using System;
-using System.Collections.Generic;
 
 namespace Xtensive.Collections.Graphs
 {
diff --git a/Orm/Xtensive.Orm/Collections/Graphs/Node{TValue}.cs b/Orm/Xtensive.Orm/Collections/Graphs/Node{TValue}.cs
index 95dcf1c50..ee3444ad6 100644
--- a/Orm/Xtensive.Orm/Collections/Graphs/Node{TValue}.cs
+++ b/Orm/Xtensive.Orm/Collections/Graphs/Node{TValue}.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2012.02.22
 
-using System;
 
 
 namespace Xtensive.Collections.Graphs
diff --git a/Orm/Xtensive.Orm/Collections/Graphs/TopologicalSortResult.cs b/Orm/Xtensive.Orm/Collections/Graphs/TopologicalSortResult.cs
index 9dd39579b..53765468e 100644
--- a/Orm/Xtensive.Orm/Collections/Graphs/TopologicalSortResult.cs
+++ b/Orm/Xtensive.Orm/Collections/Graphs/TopologicalSortResult.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2012.02.22
 
-using System.Collections.Generic;
 
 namespace Xtensive.Collections.Graphs
 {
diff --git a/Orm/Xtensive.Orm/Collections/Graphs/TopologicalSorter.cs b/Orm/Xtensive.Orm/Collections/Graphs/TopologicalSorter.cs
index 2468332ca..d669c16b5 100644
--- a/Orm/Xtensive.Orm/Collections/Graphs/TopologicalSorter.cs
+++ b/Orm/Xtensive.Orm/Collections/Graphs/TopologicalSorter.cs
@@ -4,10 +4,7 @@
 // Created by: Alex Yakunin
 // Created:    2012.02.22
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Core;
 
 namespace Xtensive.Collections.Graphs
diff --git a/Orm/Xtensive.Orm/Collections/Interfaces/IChangeNotifier.cs b/Orm/Xtensive.Orm/Collections/Interfaces/IChangeNotifier.cs
index 01bd96f68..6bde7b925 100644
--- a/Orm/Xtensive.Orm/Collections/Interfaces/IChangeNotifier.cs
+++ b/Orm/Xtensive.Orm/Collections/Interfaces/IChangeNotifier.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2007.10.15
 
-using System;
 using Xtensive.Collections;
 
 namespace Xtensive.Collections
diff --git a/Orm/Xtensive.Orm/Collections/Interfaces/IClassifiedCollection.cs b/Orm/Xtensive.Orm/Collections/Interfaces/IClassifiedCollection.cs
index a6f7b7ccb..8eb6e157b 100644
--- a/Orm/Xtensive.Orm/Collections/Interfaces/IClassifiedCollection.cs
+++ b/Orm/Xtensive.Orm/Collections/Interfaces/IClassifiedCollection.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2010.07.02
 
-using System;
-using System.Collections.Generic;
 using Xtensive.Collections;
 
 
diff --git a/Orm/Xtensive.Orm/Collections/Interfaces/IDeque.cs b/Orm/Xtensive.Orm/Collections/Interfaces/IDeque.cs
index 324a6f189..bfd9a5dec 100644
--- a/Orm/Xtensive.Orm/Collections/Interfaces/IDeque.cs
+++ b/Orm/Xtensive.Orm/Collections/Interfaces/IDeque.cs
@@ -4,9 +4,7 @@
 // Created by: Aleksey Gamzov
 // Created:    2008.01.07
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
 
 namespace Xtensive.Collections
 {
diff --git a/Orm/Xtensive.Orm/Collections/Interfaces/IExtensionCollection.cs b/Orm/Xtensive.Orm/Collections/Interfaces/IExtensionCollection.cs
index fc764da03..4d7ff568b 100644
--- a/Orm/Xtensive.Orm/Collections/Interfaces/IExtensionCollection.cs
+++ b/Orm/Xtensive.Orm/Collections/Interfaces/IExtensionCollection.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.07.03
 
-using System;
-using System.Collections.Generic;
 
 namespace Xtensive.Collections
 {
diff --git a/Orm/Xtensive.Orm/Collections/Interfaces/IFilterable.cs b/Orm/Xtensive.Orm/Collections/Interfaces/IFilterable.cs
index a7367f183..35ae8bc96 100644
--- a/Orm/Xtensive.Orm/Collections/Interfaces/IFilterable.cs
+++ b/Orm/Xtensive.Orm/Collections/Interfaces/IFilterable.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2007.11.13
 
-using System.Collections.Generic;
 using Xtensive.Core;
 
 namespace Xtensive.Collections
diff --git a/Orm/Xtensive.Orm/Collections/Interfaces/IPriorityQueue.cs b/Orm/Xtensive.Orm/Collections/Interfaces/IPriorityQueue.cs
index f346f8ca7..debf38c6e 100644
--- a/Orm/Xtensive.Orm/Collections/Interfaces/IPriorityQueue.cs
+++ b/Orm/Xtensive.Orm/Collections/Interfaces/IPriorityQueue.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Gamzov
 // Created:    2007.06.13
 
-using System;
-using System.Collections.Generic;
 using Xtensive.Core;
 
 
diff --git a/Orm/Xtensive.Orm/Collections/Interfaces/ITopDeque{K,V}.cs b/Orm/Xtensive.Orm/Collections/Interfaces/ITopDeque{K,V}.cs
index 23667c4be..a52128284 100644
--- a/Orm/Xtensive.Orm/Collections/Interfaces/ITopDeque{K,V}.cs
+++ b/Orm/Xtensive.Orm/Collections/Interfaces/ITopDeque{K,V}.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.08.26
 
-using System.Collections.Generic;
 
 namespace Xtensive.Collections
 {
diff --git a/Orm/Xtensive.Orm/Collections/Internals/PriorityQueueItemComparer.cs b/Orm/Xtensive.Orm/Collections/Internals/PriorityQueueItemComparer.cs
index fef57ac3d..df1cb4528 100644
--- a/Orm/Xtensive.Orm/Collections/Internals/PriorityQueueItemComparer.cs
+++ b/Orm/Xtensive.Orm/Collections/Internals/PriorityQueueItemComparer.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Gamzov
 // Created:    2007.06.14
 
-using System.Collections.Generic;
-using System;
 using Xtensive.Core;
 
 namespace Xtensive.Collections
diff --git a/Orm/Xtensive.Orm/Collections/NativeTypeClassifier.cs b/Orm/Xtensive.Orm/Collections/NativeTypeClassifier.cs
index f1828f721..be7795470 100644
--- a/Orm/Xtensive.Orm/Collections/NativeTypeClassifier.cs
+++ b/Orm/Xtensive.Orm/Collections/NativeTypeClassifier.cs
@@ -4,11 +4,8 @@
 // Created by: Alex Yakunin
 // Created:    2010.07.02
 
-using System;
-using System.Collections.Generic;
 
 using Xtensive.Reflection;
-using System.Linq;
 
 
 namespace Xtensive.Collections
diff --git a/Orm/Xtensive.Orm/Collections/ReadOnlyHashSet{T}.cs b/Orm/Xtensive.Orm/Collections/ReadOnlyHashSet{T}.cs
index c6181ff64..07a4e2471 100644
--- a/Orm/Xtensive.Orm/Collections/ReadOnlyHashSet{T}.cs
+++ b/Orm/Xtensive.Orm/Collections/ReadOnlyHashSet{T}.cs
@@ -4,9 +4,7 @@
 // Created by: Alex Yakunin
 // Created:    2009.12.14
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
 using System.Diagnostics;
 
 namespace Xtensive.Collections
diff --git a/Orm/Xtensive.Orm/Collections/SinglyLinkedList.cs b/Orm/Xtensive.Orm/Collections/SinglyLinkedList.cs
index 6654ef48c..f24965005 100644
--- a/Orm/Xtensive.Orm/Collections/SinglyLinkedList.cs
+++ b/Orm/Xtensive.Orm/Collections/SinglyLinkedList.cs
@@ -4,9 +4,7 @@
 // Created by: Alexis Kochetov
 // Created:    2010.11.19
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
 
 namespace Xtensive.Collections
 {
diff --git a/Orm/Xtensive.Orm/Collections/TopDeque.cs b/Orm/Xtensive.Orm/Collections/TopDeque.cs
index 026b42675..3cef977d3 100644
--- a/Orm/Xtensive.Orm/Collections/TopDeque.cs
+++ b/Orm/Xtensive.Orm/Collections/TopDeque.cs
@@ -4,9 +4,7 @@
 // Created by: Alex Ustinov
 // Created:    2007.05.28
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
 using System.Diagnostics;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Collections/TypeRegistration.cs b/Orm/Xtensive.Orm/Collections/TypeRegistration.cs
index 0190877de..e737fea7d 100644
--- a/Orm/Xtensive.Orm/Collections/TypeRegistration.cs
+++ b/Orm/Xtensive.Orm/Collections/TypeRegistration.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2007.08.21
 
-using System;
 using System.Diagnostics;
 using System.Reflection;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Collections/TypeRegistrationProcessorBase.cs b/Orm/Xtensive.Orm/Collections/TypeRegistrationProcessorBase.cs
index fafe28746..261b209e1 100644
--- a/Orm/Xtensive.Orm/Collections/TypeRegistrationProcessorBase.cs
+++ b/Orm/Xtensive.Orm/Collections/TypeRegistrationProcessorBase.cs
@@ -4,9 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2007.11.23
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Reflection;
 using Xtensive.Core;
 using Xtensive.Reflection;
diff --git a/Orm/Xtensive.Orm/Collections/TypeRegistry.cs b/Orm/Xtensive.Orm/Collections/TypeRegistry.cs
index 80c02cb43..1ca57e572 100644
--- a/Orm/Xtensive.Orm/Collections/TypeRegistry.cs
+++ b/Orm/Xtensive.Orm/Collections/TypeRegistry.cs
@@ -4,12 +4,9 @@
 // Created by: Dmitri Maximov
 // Created:    2007.08.03
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
 using System.Diagnostics;
 using System.Reflection;
-using System.Linq;
 using Xtensive.Core;
 using Xtensive.IoC;
 
diff --git a/Orm/Xtensive.Orm/Comparison/AdvancedComparer.cs b/Orm/Xtensive.Orm/Comparison/AdvancedComparer.cs
index 1aa4688be..3ef7773ae 100644
--- a/Orm/Xtensive.Orm/Comparison/AdvancedComparer.cs
+++ b/Orm/Xtensive.Orm/Comparison/AdvancedComparer.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.02.08
 
-using System;
-using System.Collections.Generic;
 using System.Diagnostics;
 using System.Runtime.Serialization;
 using System.Security;
diff --git a/Orm/Xtensive.Orm/Comparison/AdvancedComparerBase.cs b/Orm/Xtensive.Orm/Comparison/AdvancedComparerBase.cs
index d435561c8..585e3f577 100644
--- a/Orm/Xtensive.Orm/Comparison/AdvancedComparerBase.cs
+++ b/Orm/Xtensive.Orm/Comparison/AdvancedComparerBase.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2008.01.23
 
-using System;
 using System.Collections;
 using System.Collections.Concurrent;
 using System.Diagnostics;
diff --git a/Orm/Xtensive.Orm/Comparison/AdvancedComparerStruct.cs b/Orm/Xtensive.Orm/Comparison/AdvancedComparerStruct.cs
index c8de58fd8..3e80bf68e 100644
--- a/Orm/Xtensive.Orm/Comparison/AdvancedComparerStruct.cs
+++ b/Orm/Xtensive.Orm/Comparison/AdvancedComparerStruct.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.02.10
 
-using System;
-using System.Collections.Generic;
 using System.Runtime.Serialization;
 using System.Security;
 using System.Security.Permissions;
diff --git a/Orm/Xtensive.Orm/Comparison/CastingComparer.cs b/Orm/Xtensive.Orm/Comparison/CastingComparer.cs
index 77033a2e5..9fd0aa5ba 100644
--- a/Orm/Xtensive.Orm/Comparison/CastingComparer.cs
+++ b/Orm/Xtensive.Orm/Comparison/CastingComparer.cs
@@ -4,7 +4,6 @@
 // Created by: 
 // Created:    2008.03.06
 
-using System;
 using System.Runtime.Serialization;
 using Xtensive.Conversion;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Comparison/ComparerProvider.cs b/Orm/Xtensive.Orm/Comparison/ComparerProvider.cs
index 1adec5cc2..43841d9b7 100644
--- a/Orm/Xtensive.Orm/Comparison/ComparerProvider.cs
+++ b/Orm/Xtensive.Orm/Comparison/ComparerProvider.cs
@@ -4,8 +4,6 @@
 // Created by: Nick Svetlov
 // Created:    2008.01.14
 
-using System;
-using System.Collections.Generic;
 using System.Diagnostics;
 using System.Runtime.Serialization;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Comparison/ComparisonRule.cs b/Orm/Xtensive.Orm/Comparison/ComparisonRule.cs
index b38e14d4c..994464b3e 100644
--- a/Orm/Xtensive.Orm/Comparison/ComparisonRule.cs
+++ b/Orm/Xtensive.Orm/Comparison/ComparisonRule.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.02.05
 
-using System;
 using System.Globalization;
 using System.Runtime.Serialization;
 using System.Security;
diff --git a/Orm/Xtensive.Orm/Comparison/ComparisonRules.cs b/Orm/Xtensive.Orm/Comparison/ComparisonRules.cs
index f72e43309..618d82e68 100644
--- a/Orm/Xtensive.Orm/Comparison/ComparisonRules.cs
+++ b/Orm/Xtensive.Orm/Comparison/ComparisonRules.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Kochetov
 // Created:    2008.02.04
 
-using System;
-using System.Collections.Generic;
 using System.Diagnostics;
 using System.Text;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Comparison/Interfaces/IAdvancedComparer.cs b/Orm/Xtensive.Orm/Comparison/Interfaces/IAdvancedComparer.cs
index fd2e92a86..589beb1d2 100644
--- a/Orm/Xtensive.Orm/Comparison/Interfaces/IAdvancedComparer.cs
+++ b/Orm/Xtensive.Orm/Comparison/Interfaces/IAdvancedComparer.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.01.22
 
-using System;
-using System.Collections.Generic;
 
 namespace Xtensive.Comparison
 {
diff --git a/Orm/Xtensive.Orm/Comparison/Interfaces/IComparerProvider.cs b/Orm/Xtensive.Orm/Comparison/Interfaces/IComparerProvider.cs
index 9caf4aad5..f554e1534 100644
--- a/Orm/Xtensive.Orm/Comparison/Interfaces/IComparerProvider.cs
+++ b/Orm/Xtensive.Orm/Comparison/Interfaces/IComparerProvider.cs
@@ -4,7 +4,6 @@
 // Created by: Nick Svetlov
 // Created:    2008.01.14
 
-using System.Collections.Generic;
 
 namespace Xtensive.Comparison
 {
diff --git a/Orm/Xtensive.Orm/Comparison/Internals/ArrayComparer.cs b/Orm/Xtensive.Orm/Comparison/Internals/ArrayComparer.cs
index e775b0673..37bfd581c 100644
--- a/Orm/Xtensive.Orm/Comparison/Internals/ArrayComparer.cs
+++ b/Orm/Xtensive.Orm/Comparison/Internals/ArrayComparer.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2008.01.16
 
-using System;
 using System.Runtime.Serialization;
 
 namespace Xtensive.Comparison
diff --git a/Orm/Xtensive.Orm/Comparison/Internals/AssemblyComparer.cs b/Orm/Xtensive.Orm/Comparison/Internals/AssemblyComparer.cs
index af3e73747..c3a78266d 100644
--- a/Orm/Xtensive.Orm/Comparison/Internals/AssemblyComparer.cs
+++ b/Orm/Xtensive.Orm/Comparison/Internals/AssemblyComparer.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.01.22
 
-using System;
 using System.Reflection;
 using System.Runtime.Serialization;
 
diff --git a/Orm/Xtensive.Orm/Comparison/Internals/BaseComparerWrapper.cs b/Orm/Xtensive.Orm/Comparison/Internals/BaseComparerWrapper.cs
index ef4e624db..a6c62e300 100644
--- a/Orm/Xtensive.Orm/Comparison/Internals/BaseComparerWrapper.cs
+++ b/Orm/Xtensive.Orm/Comparison/Internals/BaseComparerWrapper.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.01.22
 
-using System;
 using System.Runtime.Serialization;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Comparison/Internals/BooleanComparer.cs b/Orm/Xtensive.Orm/Comparison/Internals/BooleanComparer.cs
index 0b5fd6ad6..6aa4c8420 100644
--- a/Orm/Xtensive.Orm/Comparison/Internals/BooleanComparer.cs
+++ b/Orm/Xtensive.Orm/Comparison/Internals/BooleanComparer.cs
@@ -4,7 +4,6 @@
 // Created by: Nick Svetlov
 // Created:    2007.11.28
 
-using System;
 using System.Runtime.Serialization;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Comparison/Internals/ByteComparer.cs b/Orm/Xtensive.Orm/Comparison/Internals/ByteComparer.cs
index ebef97031..f026dcd83 100644
--- a/Orm/Xtensive.Orm/Comparison/Internals/ByteComparer.cs
+++ b/Orm/Xtensive.Orm/Comparison/Internals/ByteComparer.cs
@@ -4,7 +4,6 @@
 // Created by: Nick Svetlov
 // Created:    2007.11.28
 
-using System;
 using System.Runtime.Serialization;
 
 namespace Xtensive.Comparison
diff --git a/Orm/Xtensive.Orm/Comparison/Internals/CharComparer.cs b/Orm/Xtensive.Orm/Comparison/Internals/CharComparer.cs
index 6a2eca9ed..f2bc9c2af 100644
--- a/Orm/Xtensive.Orm/Comparison/Internals/CharComparer.cs
+++ b/Orm/Xtensive.Orm/Comparison/Internals/CharComparer.cs
@@ -4,7 +4,6 @@
 // Created by: Nick Svetlov
 // Created:    2007.11.28
 
-using System;
 using System.Runtime.Serialization;
 
 namespace Xtensive.Comparison
diff --git a/Orm/Xtensive.Orm/Comparison/Internals/DecimalComparer.cs b/Orm/Xtensive.Orm/Comparison/Internals/DecimalComparer.cs
index 2190b2c79..83abb70f6 100644
--- a/Orm/Xtensive.Orm/Comparison/Internals/DecimalComparer.cs
+++ b/Orm/Xtensive.Orm/Comparison/Internals/DecimalComparer.cs
@@ -4,7 +4,6 @@
 // Created by: Nick Svetlov
 // Created:    2007.11.28
 
-using System;
 using System.Runtime.Serialization;
 
 namespace Xtensive.Comparison
diff --git a/Orm/Xtensive.Orm/Comparison/Internals/DoubleComparer.cs b/Orm/Xtensive.Orm/Comparison/Internals/DoubleComparer.cs
index 7d8fe1167..06d46030c 100644
--- a/Orm/Xtensive.Orm/Comparison/Internals/DoubleComparer.cs
+++ b/Orm/Xtensive.Orm/Comparison/Internals/DoubleComparer.cs
@@ -4,7 +4,6 @@
 // Created by: Nick Svetlov
 // Created:    2007.11.28
 
-using System;
 using System.Runtime.Serialization;
 
 namespace Xtensive.Comparison
diff --git a/Orm/Xtensive.Orm/Comparison/Internals/EnumComparer.cs b/Orm/Xtensive.Orm/Comparison/Internals/EnumComparer.cs
index fd904619e..5d283ad01 100644
--- a/Orm/Xtensive.Orm/Comparison/Internals/EnumComparer.cs
+++ b/Orm/Xtensive.Orm/Comparison/Internals/EnumComparer.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.01.23
 
-using System;
-using System.Collections.Generic;
 using System.Runtime.Serialization;
 using System.Security;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Comparison/Internals/EnumerableInterfaceComparer.cs b/Orm/Xtensive.Orm/Comparison/Internals/EnumerableInterfaceComparer.cs
index af5896047..e8e24c2a2 100644
--- a/Orm/Xtensive.Orm/Comparison/Internals/EnumerableInterfaceComparer.cs
+++ b/Orm/Xtensive.Orm/Comparison/Internals/EnumerableInterfaceComparer.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2008.01.16
 
-using System;
-using System.Collections.Generic;
 using System.Runtime.Serialization;
 
 namespace Xtensive.Comparison
diff --git a/Orm/Xtensive.Orm/Comparison/Internals/GuidComparer.cs b/Orm/Xtensive.Orm/Comparison/Internals/GuidComparer.cs
index 42271594d..ba69576c6 100644
--- a/Orm/Xtensive.Orm/Comparison/Internals/GuidComparer.cs
+++ b/Orm/Xtensive.Orm/Comparison/Internals/GuidComparer.cs
@@ -4,7 +4,6 @@
 // Created by: Nick Svetlov
 // Created:    2007.11.28
 
-using System;
 using System.Runtime.Serialization;
 
 namespace Xtensive.Comparison
diff --git a/Orm/Xtensive.Orm/Comparison/Internals/Int16Comparer.cs b/Orm/Xtensive.Orm/Comparison/Internals/Int16Comparer.cs
index fe10bc585..d975f81e8 100644
--- a/Orm/Xtensive.Orm/Comparison/Internals/Int16Comparer.cs
+++ b/Orm/Xtensive.Orm/Comparison/Internals/Int16Comparer.cs
@@ -4,7 +4,6 @@
 // Created by: Nick Svetlov
 // Created:    2007.11.28
 
-using System;
 using System.Runtime.Serialization;
 
 namespace Xtensive.Comparison
diff --git a/Orm/Xtensive.Orm/Comparison/Internals/Int32Comparer.cs b/Orm/Xtensive.Orm/Comparison/Internals/Int32Comparer.cs
index bbe22f1d0..db0a84eba 100644
--- a/Orm/Xtensive.Orm/Comparison/Internals/Int32Comparer.cs
+++ b/Orm/Xtensive.Orm/Comparison/Internals/Int32Comparer.cs
@@ -4,7 +4,6 @@
 // Created by: Nick Svetlov
 // Created:    2007.11.28
 
-using System;
 using System.Runtime.Serialization;
 
 namespace Xtensive.Comparison
diff --git a/Orm/Xtensive.Orm/Comparison/Internals/Int64Comparer.cs b/Orm/Xtensive.Orm/Comparison/Internals/Int64Comparer.cs
index 50dfb9d1c..eb7585639 100644
--- a/Orm/Xtensive.Orm/Comparison/Internals/Int64Comparer.cs
+++ b/Orm/Xtensive.Orm/Comparison/Internals/Int64Comparer.cs
@@ -4,7 +4,6 @@
 // Created by: Nick Svetlov
 // Created:    2007.11.28
 
-using System;
 using System.Runtime.Serialization;
 
 namespace Xtensive.Comparison
diff --git a/Orm/Xtensive.Orm/Comparison/Internals/KeyValuePairComparer.cs b/Orm/Xtensive.Orm/Comparison/Internals/KeyValuePairComparer.cs
index c61ff9bf5..a3be09995 100644
--- a/Orm/Xtensive.Orm/Comparison/Internals/KeyValuePairComparer.cs
+++ b/Orm/Xtensive.Orm/Comparison/Internals/KeyValuePairComparer.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.01.22
 
-using System;
-using System.Collections.Generic;
 using System.Runtime.Serialization;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Comparison/Internals/NoSystemComparerHandler.cs b/Orm/Xtensive.Orm/Comparison/Internals/NoSystemComparerHandler.cs
index 5322856c9..930cd8c89 100644
--- a/Orm/Xtensive.Orm/Comparison/Internals/NoSystemComparerHandler.cs
+++ b/Orm/Xtensive.Orm/Comparison/Internals/NoSystemComparerHandler.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.02.10
 
-using System;
 using Xtensive.Reflection;
 
 
diff --git a/Orm/Xtensive.Orm/Comparison/Internals/NullableComparer.cs b/Orm/Xtensive.Orm/Comparison/Internals/NullableComparer.cs
index 935248b46..0abbd273c 100644
--- a/Orm/Xtensive.Orm/Comparison/Internals/NullableComparer.cs
+++ b/Orm/Xtensive.Orm/Comparison/Internals/NullableComparer.cs
@@ -4,7 +4,6 @@
 // Created by: 
 // Created:    2008.01.23
 
-using System;
 using System.Runtime.Serialization;
 using System.Security;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Comparison/Internals/ObjectComparer.cs b/Orm/Xtensive.Orm/Comparison/Internals/ObjectComparer.cs
index f53972f32..bbb291972 100644
--- a/Orm/Xtensive.Orm/Comparison/Internals/ObjectComparer.cs
+++ b/Orm/Xtensive.Orm/Comparison/Internals/ObjectComparer.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.01.23
 
-using System;
-using System.Collections.Generic;
 using System.Runtime.Serialization;
 
 namespace Xtensive.Comparison
diff --git a/Orm/Xtensive.Orm/Comparison/Internals/PairComparer{T1,T2}.cs b/Orm/Xtensive.Orm/Comparison/Internals/PairComparer{T1,T2}.cs
index db277ef56..6a232c365 100644
--- a/Orm/Xtensive.Orm/Comparison/Internals/PairComparer{T1,T2}.cs
+++ b/Orm/Xtensive.Orm/Comparison/Internals/PairComparer{T1,T2}.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.01.22
 
-using System;
 using System.Runtime.Serialization;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Comparison/Internals/PairComparer{T}.cs b/Orm/Xtensive.Orm/Comparison/Internals/PairComparer{T}.cs
index 86d7f2ffe..ca6dd2888 100644
--- a/Orm/Xtensive.Orm/Comparison/Internals/PairComparer{T}.cs
+++ b/Orm/Xtensive.Orm/Comparison/Internals/PairComparer{T}.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.01.22
 
-using System;
 using System.Runtime.Serialization;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Comparison/Internals/SByteComparer.cs b/Orm/Xtensive.Orm/Comparison/Internals/SByteComparer.cs
index 720d62b58..36ce588f8 100644
--- a/Orm/Xtensive.Orm/Comparison/Internals/SByteComparer.cs
+++ b/Orm/Xtensive.Orm/Comparison/Internals/SByteComparer.cs
@@ -4,7 +4,6 @@
 // Created by: Nick Svetlov
 // Created:    2007.11.28
 
-using System;
 using System.Runtime.Serialization;
 
 namespace Xtensive.Comparison
diff --git a/Orm/Xtensive.Orm/Comparison/Internals/SingleComparer.cs b/Orm/Xtensive.Orm/Comparison/Internals/SingleComparer.cs
index a7c901bbe..db8245c59 100644
--- a/Orm/Xtensive.Orm/Comparison/Internals/SingleComparer.cs
+++ b/Orm/Xtensive.Orm/Comparison/Internals/SingleComparer.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2007.11.14
 
-using System;
 using System.Runtime.Serialization;
 
 namespace Xtensive.Comparison
diff --git a/Orm/Xtensive.Orm/Comparison/Internals/StringComparer.cs b/Orm/Xtensive.Orm/Comparison/Internals/StringComparer.cs
index 006eacfcf..73b737f9d 100644
--- a/Orm/Xtensive.Orm/Comparison/Internals/StringComparer.cs
+++ b/Orm/Xtensive.Orm/Comparison/Internals/StringComparer.cs
@@ -4,7 +4,6 @@
 // Created by: Nick Svetlov
 // Created:    2007.11.28
 
-using System;
 using System.Globalization;
 using System.Runtime.Serialization;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Comparison/Internals/SystemComparerStruct.cs b/Orm/Xtensive.Orm/Comparison/Internals/SystemComparerStruct.cs
index ee6930f15..a1bfe0fd1 100644
--- a/Orm/Xtensive.Orm/Comparison/Internals/SystemComparerStruct.cs
+++ b/Orm/Xtensive.Orm/Comparison/Internals/SystemComparerStruct.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.02.10
 
-using System;
-using System.Collections.Generic;
 using System.Runtime.Serialization;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Comparison/Internals/TupleComparer.cs b/Orm/Xtensive.Orm/Comparison/Internals/TupleComparer.cs
index 98fd93171..6b9996548 100644
--- a/Orm/Xtensive.Orm/Comparison/Internals/TupleComparer.cs
+++ b/Orm/Xtensive.Orm/Comparison/Internals/TupleComparer.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.01.29
 
-using System;
 using System.Runtime.Serialization;
 using Tuple = Xtensive.Tuples.Tuple;
 
diff --git a/Orm/Xtensive.Orm/Comparison/Internals/TupleDescriptorComparer.cs b/Orm/Xtensive.Orm/Comparison/Internals/TupleDescriptorComparer.cs
index 8252629eb..975d708e6 100644
--- a/Orm/Xtensive.Orm/Comparison/Internals/TupleDescriptorComparer.cs
+++ b/Orm/Xtensive.Orm/Comparison/Internals/TupleDescriptorComparer.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.01.22
 
-using System;
 using System.Reflection;
 using System.Runtime.Serialization;
 using Xtensive.Collections;
diff --git a/Orm/Xtensive.Orm/Comparison/Internals/TypeComparer.cs b/Orm/Xtensive.Orm/Comparison/Internals/TypeComparer.cs
index ada19dc97..a3a13d548 100644
--- a/Orm/Xtensive.Orm/Comparison/Internals/TypeComparer.cs
+++ b/Orm/Xtensive.Orm/Comparison/Internals/TypeComparer.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.01.22
 
-using System;
 using System.Collections.Concurrent;
 using System.Reflection;
 using System.Runtime.Serialization;
diff --git a/Orm/Xtensive.Orm/Comparison/Internals/UInt16Comparer.cs b/Orm/Xtensive.Orm/Comparison/Internals/UInt16Comparer.cs
index 19c230f0f..7128b8f07 100644
--- a/Orm/Xtensive.Orm/Comparison/Internals/UInt16Comparer.cs
+++ b/Orm/Xtensive.Orm/Comparison/Internals/UInt16Comparer.cs
@@ -4,7 +4,6 @@
 // Created by: Nick Svetlov
 // Created:    2007.11.28
 
-using System;
 using System.Runtime.Serialization;
 
 namespace Xtensive.Comparison
diff --git a/Orm/Xtensive.Orm/Comparison/Internals/UInt32Comparer.cs b/Orm/Xtensive.Orm/Comparison/Internals/UInt32Comparer.cs
index 31c0fecb5..b50a0be50 100644
--- a/Orm/Xtensive.Orm/Comparison/Internals/UInt32Comparer.cs
+++ b/Orm/Xtensive.Orm/Comparison/Internals/UInt32Comparer.cs
@@ -4,7 +4,6 @@
 // Created by: Nick Svetlov
 // Created:    2007.11.28
 
-using System;
 using System.Runtime.Serialization;
 
 namespace Xtensive.Comparison
diff --git a/Orm/Xtensive.Orm/Comparison/Internals/UInt64Comparer.cs b/Orm/Xtensive.Orm/Comparison/Internals/UInt64Comparer.cs
index 5fc58bfe5..9174f37b8 100644
--- a/Orm/Xtensive.Orm/Comparison/Internals/UInt64Comparer.cs
+++ b/Orm/Xtensive.Orm/Comparison/Internals/UInt64Comparer.cs
@@ -4,7 +4,6 @@
 // Created by: Nick Svetlov
 // Created:    2007.11.28
 
-using System;
 using System.Runtime.Serialization;
 
 namespace Xtensive.Comparison
diff --git a/Orm/Xtensive.Orm/Comparison/Internals/ValueTypeComparer.cs b/Orm/Xtensive.Orm/Comparison/Internals/ValueTypeComparer.cs
index 6bb7a151b..ad251f720 100644
--- a/Orm/Xtensive.Orm/Comparison/Internals/ValueTypeComparer.cs
+++ b/Orm/Xtensive.Orm/Comparison/Internals/ValueTypeComparer.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.01.23
 
-using System;
-using System.Collections.Generic;
 using System.Reflection;
 using System.Runtime.Serialization;
 
diff --git a/Orm/Xtensive.Orm/Comparison/Internals/ValueTypeComparerBase.cs b/Orm/Xtensive.Orm/Comparison/Internals/ValueTypeComparerBase.cs
index 19a457b3c..131fb4076 100644
--- a/Orm/Xtensive.Orm/Comparison/Internals/ValueTypeComparerBase.cs
+++ b/Orm/Xtensive.Orm/Comparison/Internals/ValueTypeComparerBase.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.01.23
 
-using System;
-using System.Collections.Generic;
 using System.Reflection;
 using System.Runtime.Serialization;
 
diff --git a/Orm/Xtensive.Orm/Comparison/ReferenceEqualityComparer.cs b/Orm/Xtensive.Orm/Comparison/ReferenceEqualityComparer.cs
index 83ad94a00..9f06a204b 100644
--- a/Orm/Xtensive.Orm/Comparison/ReferenceEqualityComparer.cs
+++ b/Orm/Xtensive.Orm/Comparison/ReferenceEqualityComparer.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.09.01
 
-using System;
-using System.Collections.Generic;
 using System.Diagnostics;
 using System.Runtime.CompilerServices;
 
diff --git a/Orm/Xtensive.Orm/Comparison/SystemComparer.cs b/Orm/Xtensive.Orm/Comparison/SystemComparer.cs
index e83903d37..25e2f2a1b 100644
--- a/Orm/Xtensive.Orm/Comparison/SystemComparer.cs
+++ b/Orm/Xtensive.Orm/Comparison/SystemComparer.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.02.10
 
-using System;
 using System.Runtime.Serialization;
 
 namespace Xtensive.Comparison
diff --git a/Orm/Xtensive.Orm/Comparison/SystemComparerProvider.cs b/Orm/Xtensive.Orm/Comparison/SystemComparerProvider.cs
index a717aa738..28590a3e0 100644
--- a/Orm/Xtensive.Orm/Comparison/SystemComparerProvider.cs
+++ b/Orm/Xtensive.Orm/Comparison/SystemComparerProvider.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.02.10
 
-using System;
 using System.Diagnostics;
 using System.Runtime.Serialization;
 
diff --git a/Orm/Xtensive.Orm/Comparison/ValueRangeInfo.cs b/Orm/Xtensive.Orm/Comparison/ValueRangeInfo.cs
index 45047bd35..762aae4df 100644
--- a/Orm/Xtensive.Orm/Comparison/ValueRangeInfo.cs
+++ b/Orm/Xtensive.Orm/Comparison/ValueRangeInfo.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2008.01.23
 
-using System;
 using Xtensive.Arithmetic;
 
 
diff --git a/Orm/Xtensive.Orm/Comparison/WrappingComparer{T,TBase1,TBase2}.cs b/Orm/Xtensive.Orm/Comparison/WrappingComparer{T,TBase1,TBase2}.cs
index 70dcb6260..3fa2efeb2 100644
--- a/Orm/Xtensive.Orm/Comparison/WrappingComparer{T,TBase1,TBase2}.cs
+++ b/Orm/Xtensive.Orm/Comparison/WrappingComparer{T,TBase1,TBase2}.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.01.21
 
-using System;
 using System.Runtime.Serialization;
 using System.Security;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Comparison/WrappingComparer{T,TBase}.cs b/Orm/Xtensive.Orm/Comparison/WrappingComparer{T,TBase}.cs
index 9b802f23a..631dcc6f1 100644
--- a/Orm/Xtensive.Orm/Comparison/WrappingComparer{T,TBase}.cs
+++ b/Orm/Xtensive.Orm/Comparison/WrappingComparer{T,TBase}.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.01.21
 
-using System;
 using System.Runtime.Serialization;
 using System.Security;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Conversion/AdvancedConverter.cs b/Orm/Xtensive.Orm/Conversion/AdvancedConverter.cs
index 2d5bc7e34..f7fe28ae8 100644
--- a/Orm/Xtensive.Orm/Conversion/AdvancedConverter.cs
+++ b/Orm/Xtensive.Orm/Conversion/AdvancedConverter.cs
@@ -4,10 +4,8 @@
 // Created by: Alexey Gamzov
 // Created:    2008.02.15
 
-using System;
 using System.Diagnostics;
 using System.Runtime.Serialization;
-using System.Threading;
 using Xtensive.Core;
 
 
diff --git a/Orm/Xtensive.Orm/Conversion/AdvancedConverterBase.cs b/Orm/Xtensive.Orm/Conversion/AdvancedConverterBase.cs
index e42ed05a7..9fcb0f6a8 100644
--- a/Orm/Xtensive.Orm/Conversion/AdvancedConverterBase.cs
+++ b/Orm/Xtensive.Orm/Conversion/AdvancedConverterBase.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2008.02.15
 
-using System;
 using System.Diagnostics;
 using System.Runtime.Serialization;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Conversion/AdvancedConverterProvider.cs b/Orm/Xtensive.Orm/Conversion/AdvancedConverterProvider.cs
index b676265f8..256fabf21 100644
--- a/Orm/Xtensive.Orm/Conversion/AdvancedConverterProvider.cs
+++ b/Orm/Xtensive.Orm/Conversion/AdvancedConverterProvider.cs
@@ -4,10 +4,7 @@
 // Created by: Alexey Gamzov
 // Created:    2008.01.21
 
-using System;
-using System.Collections.Generic;
 using System.Diagnostics;
-using System.Threading;
 using Xtensive.Core;
 
 
diff --git a/Orm/Xtensive.Orm/Conversion/AdvancedConverterStruct.cs b/Orm/Xtensive.Orm/Conversion/AdvancedConverterStruct.cs
index a03d971d4..2f6426a42 100644
--- a/Orm/Xtensive.Orm/Conversion/AdvancedConverterStruct.cs
+++ b/Orm/Xtensive.Orm/Conversion/AdvancedConverterStruct.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2008.02.15
 
-using System;
 using System.Runtime.Serialization;
 using System.Security;
 using System.Security.Permissions;
diff --git a/Orm/Xtensive.Orm/Conversion/Biconverter.cs b/Orm/Xtensive.Orm/Conversion/Biconverter.cs
index 174512e7d..3560c4f33 100644
--- a/Orm/Xtensive.Orm/Conversion/Biconverter.cs
+++ b/Orm/Xtensive.Orm/Conversion/Biconverter.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kochetov
 // Created:    2007.10.03
 
-using System;
 
 
 namespace Xtensive.Conversion
diff --git a/Orm/Xtensive.Orm/Conversion/ConvertingEnumerable.cs b/Orm/Xtensive.Orm/Conversion/ConvertingEnumerable.cs
index f533c0028..825aa7faf 100644
--- a/Orm/Xtensive.Orm/Conversion/ConvertingEnumerable.cs
+++ b/Orm/Xtensive.Orm/Conversion/ConvertingEnumerable.cs
@@ -4,9 +4,7 @@
 // Created by: Alex Ilyin
 // Created:    2007.06.04
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
 using Xtensive.Core;
 
 
diff --git a/Orm/Xtensive.Orm/Conversion/Interfaces/IAdvancedConverterFactory.cs b/Orm/Xtensive.Orm/Conversion/Interfaces/IAdvancedConverterFactory.cs
index 1662f4a04..4b6085be2 100644
--- a/Orm/Xtensive.Orm/Conversion/Interfaces/IAdvancedConverterFactory.cs
+++ b/Orm/Xtensive.Orm/Conversion/Interfaces/IAdvancedConverterFactory.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2008.02.14
 
-using System;
 
 namespace Xtensive.Conversion
 {
diff --git a/Orm/Xtensive.Orm/Conversion/Interfaces/IAdvancedConverterProvider.cs b/Orm/Xtensive.Orm/Conversion/Interfaces/IAdvancedConverterProvider.cs
index 815d0df38..6d7a9ae99 100644
--- a/Orm/Xtensive.Orm/Conversion/Interfaces/IAdvancedConverterProvider.cs
+++ b/Orm/Xtensive.Orm/Conversion/Interfaces/IAdvancedConverterProvider.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2008.01.21
 
-using System;
 
 namespace Xtensive.Conversion
 {
diff --git a/Orm/Xtensive.Orm/Conversion/Internals/BooleanAdvancedConverter.cs b/Orm/Xtensive.Orm/Conversion/Internals/BooleanAdvancedConverter.cs
index 61bd631af..13ffa8080 100644
--- a/Orm/Xtensive.Orm/Conversion/Internals/BooleanAdvancedConverter.cs
+++ b/Orm/Xtensive.Orm/Conversion/Internals/BooleanAdvancedConverter.cs
@@ -4,7 +4,6 @@
 // Created by: Roman Churakov
 // Created:    2008.01.22
 
-using System;
 
 namespace Xtensive.Conversion
 {
diff --git a/Orm/Xtensive.Orm/Conversion/Internals/ByteAdvancedConverter.cs b/Orm/Xtensive.Orm/Conversion/Internals/ByteAdvancedConverter.cs
index b0ec7e77f..30392515d 100644
--- a/Orm/Xtensive.Orm/Conversion/Internals/ByteAdvancedConverter.cs
+++ b/Orm/Xtensive.Orm/Conversion/Internals/ByteAdvancedConverter.cs
@@ -4,7 +4,6 @@
 // Created by: Roman Churakov
 // Created:    2008.01.22
 
-using System;
 using System.Globalization;
 
 namespace Xtensive.Conversion
diff --git a/Orm/Xtensive.Orm/Conversion/Internals/ByteRoughAdvancedConverter.cs b/Orm/Xtensive.Orm/Conversion/Internals/ByteRoughAdvancedConverter.cs
index 115617151..2779ca74f 100644
--- a/Orm/Xtensive.Orm/Conversion/Internals/ByteRoughAdvancedConverter.cs
+++ b/Orm/Xtensive.Orm/Conversion/Internals/ByteRoughAdvancedConverter.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2008.02.08
 
-using System;
 
 namespace Xtensive.Conversion
 {
diff --git a/Orm/Xtensive.Orm/Conversion/Internals/CharAdvancedConverter.cs b/Orm/Xtensive.Orm/Conversion/Internals/CharAdvancedConverter.cs
index 0e1ee35cc..188069d5e 100644
--- a/Orm/Xtensive.Orm/Conversion/Internals/CharAdvancedConverter.cs
+++ b/Orm/Xtensive.Orm/Conversion/Internals/CharAdvancedConverter.cs
@@ -4,7 +4,6 @@
 // Created by: Roman Churakov
 // Created:    2008.01.23
 
-using System;
 
 namespace Xtensive.Conversion
 {
diff --git a/Orm/Xtensive.Orm/Conversion/Internals/ConvertingEnumerator.cs b/Orm/Xtensive.Orm/Conversion/Internals/ConvertingEnumerator.cs
index f68f5dc51..cb05990ff 100644
--- a/Orm/Xtensive.Orm/Conversion/Internals/ConvertingEnumerator.cs
+++ b/Orm/Xtensive.Orm/Conversion/Internals/ConvertingEnumerator.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Ilyin
 // Created:    2007.06.04
 
-using System;
-using System.Collections.Generic;
 using Xtensive.Core;
 
 
diff --git a/Orm/Xtensive.Orm/Conversion/Internals/DateTimeAdvancedConverter.cs b/Orm/Xtensive.Orm/Conversion/Internals/DateTimeAdvancedConverter.cs
index ee3cfa080..c36edc822 100644
--- a/Orm/Xtensive.Orm/Conversion/Internals/DateTimeAdvancedConverter.cs
+++ b/Orm/Xtensive.Orm/Conversion/Internals/DateTimeAdvancedConverter.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2008.01.23
 
-using System;
 using System.Globalization;
 
 namespace Xtensive.Conversion
diff --git a/Orm/Xtensive.Orm/Conversion/Internals/DateTimeRoughAdvancedConverter.cs b/Orm/Xtensive.Orm/Conversion/Internals/DateTimeRoughAdvancedConverter.cs
index 278fcb2b2..3f9214961 100644
--- a/Orm/Xtensive.Orm/Conversion/Internals/DateTimeRoughAdvancedConverter.cs
+++ b/Orm/Xtensive.Orm/Conversion/Internals/DateTimeRoughAdvancedConverter.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2008.02.08
 
-using System;
 
 namespace Xtensive.Conversion
 {
diff --git a/Orm/Xtensive.Orm/Conversion/Internals/DecimalAdvancedConverter.cs b/Orm/Xtensive.Orm/Conversion/Internals/DecimalAdvancedConverter.cs
index f1884ea86..098892c3e 100644
--- a/Orm/Xtensive.Orm/Conversion/Internals/DecimalAdvancedConverter.cs
+++ b/Orm/Xtensive.Orm/Conversion/Internals/DecimalAdvancedConverter.cs
@@ -4,7 +4,6 @@
 // Created by: Roman Churakov
 // Created:    2008.01.23
 
-using System;
 using System.Globalization;
 
 namespace Xtensive.Conversion
diff --git a/Orm/Xtensive.Orm/Conversion/Internals/DecimalRoughAdvancedConverter.cs b/Orm/Xtensive.Orm/Conversion/Internals/DecimalRoughAdvancedConverter.cs
index c3bfa0996..eb6047627 100644
--- a/Orm/Xtensive.Orm/Conversion/Internals/DecimalRoughAdvancedConverter.cs
+++ b/Orm/Xtensive.Orm/Conversion/Internals/DecimalRoughAdvancedConverter.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2008.02.08
 
-using System;
 
 namespace Xtensive.Conversion
 {
diff --git a/Orm/Xtensive.Orm/Conversion/Internals/DoubleAdvancedConverter.cs b/Orm/Xtensive.Orm/Conversion/Internals/DoubleAdvancedConverter.cs
index 0e96e47d3..0daab0d8c 100644
--- a/Orm/Xtensive.Orm/Conversion/Internals/DoubleAdvancedConverter.cs
+++ b/Orm/Xtensive.Orm/Conversion/Internals/DoubleAdvancedConverter.cs
@@ -4,7 +4,6 @@
 // Created by: Roman Churakov
 // Created:    2008.01.23
 
-using System;
 using System.Globalization;
 
 namespace Xtensive.Conversion
diff --git a/Orm/Xtensive.Orm/Conversion/Internals/DoubleRoughAdvancedConverter.cs b/Orm/Xtensive.Orm/Conversion/Internals/DoubleRoughAdvancedConverter.cs
index c1650425c..708ab0c60 100644
--- a/Orm/Xtensive.Orm/Conversion/Internals/DoubleRoughAdvancedConverter.cs
+++ b/Orm/Xtensive.Orm/Conversion/Internals/DoubleRoughAdvancedConverter.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2008.02.08
 
-using System;
 
 namespace Xtensive.Conversion
 {
diff --git a/Orm/Xtensive.Orm/Conversion/Internals/EnumAdvancedConverterFactory.cs b/Orm/Xtensive.Orm/Conversion/Internals/EnumAdvancedConverterFactory.cs
index 631ac2a91..05b878072 100644
--- a/Orm/Xtensive.Orm/Conversion/Internals/EnumAdvancedConverterFactory.cs
+++ b/Orm/Xtensive.Orm/Conversion/Internals/EnumAdvancedConverterFactory.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2008.02.14
 
-using System;
 using Xtensive.Reflection;
 
 namespace Xtensive.Conversion
diff --git a/Orm/Xtensive.Orm/Conversion/Internals/EnumAdvancedConverter{TFrom, TTo, TIntermediate}.cs b/Orm/Xtensive.Orm/Conversion/Internals/EnumAdvancedConverter{TFrom, TTo, TIntermediate}.cs
index d6a6088ad..03faa7564 100644
--- a/Orm/Xtensive.Orm/Conversion/Internals/EnumAdvancedConverter{TFrom, TTo, TIntermediate}.cs	
+++ b/Orm/Xtensive.Orm/Conversion/Internals/EnumAdvancedConverter{TFrom, TTo, TIntermediate}.cs	
@@ -4,7 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2008.02.15
 
-using System;
 using Xtensive.Reflection;
 
 namespace Xtensive.Conversion
diff --git a/Orm/Xtensive.Orm/Conversion/Internals/EnumAdvancedConverter{TFrom, TTo, TUnderlyingFrom, TUnderlyingTo}.cs b/Orm/Xtensive.Orm/Conversion/Internals/EnumAdvancedConverter{TFrom, TTo, TUnderlyingFrom, TUnderlyingTo}.cs
index c8e691cd4..928fbb87b 100644
--- a/Orm/Xtensive.Orm/Conversion/Internals/EnumAdvancedConverter{TFrom, TTo, TUnderlyingFrom, TUnderlyingTo}.cs	
+++ b/Orm/Xtensive.Orm/Conversion/Internals/EnumAdvancedConverter{TFrom, TTo, TUnderlyingFrom, TUnderlyingTo}.cs	
@@ -4,7 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2008.02.14
 
-using System;
 using Xtensive.Reflection;
 
 namespace Xtensive.Conversion
diff --git a/Orm/Xtensive.Orm/Conversion/Internals/EnumAdvancedConverter{TFrom, TTo}.cs b/Orm/Xtensive.Orm/Conversion/Internals/EnumAdvancedConverter{TFrom, TTo}.cs
index 6f5212227..049619f9b 100644
--- a/Orm/Xtensive.Orm/Conversion/Internals/EnumAdvancedConverter{TFrom, TTo}.cs	
+++ b/Orm/Xtensive.Orm/Conversion/Internals/EnumAdvancedConverter{TFrom, TTo}.cs	
@@ -4,7 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2008.02.15
 
-using System;
 using Xtensive.Reflection;
 
 namespace Xtensive.Conversion
diff --git a/Orm/Xtensive.Orm/Conversion/Internals/GuidAdvancedConverter.cs b/Orm/Xtensive.Orm/Conversion/Internals/GuidAdvancedConverter.cs
index 96ab72e77..3b8f1f178 100644
--- a/Orm/Xtensive.Orm/Conversion/Internals/GuidAdvancedConverter.cs
+++ b/Orm/Xtensive.Orm/Conversion/Internals/GuidAdvancedConverter.cs
@@ -4,7 +4,6 @@
 // Created by: Roman Churakov
 // Created:    2008.01.23
 
-using System;
 
 namespace Xtensive.Conversion
 {
diff --git a/Orm/Xtensive.Orm/Conversion/Internals/Int16AdvancedConverter.cs b/Orm/Xtensive.Orm/Conversion/Internals/Int16AdvancedConverter.cs
index 8d13df7bc..dd8900833 100644
--- a/Orm/Xtensive.Orm/Conversion/Internals/Int16AdvancedConverter.cs
+++ b/Orm/Xtensive.Orm/Conversion/Internals/Int16AdvancedConverter.cs
@@ -4,7 +4,6 @@
 // Created by: Roman Churakov
 // Created:    2008.01.22
 
-using System;
 using System.Globalization;
 
 namespace Xtensive.Conversion
diff --git a/Orm/Xtensive.Orm/Conversion/Internals/Int16RoughAdvancedConverter.cs b/Orm/Xtensive.Orm/Conversion/Internals/Int16RoughAdvancedConverter.cs
index 4c251aab9..d4638afaf 100644
--- a/Orm/Xtensive.Orm/Conversion/Internals/Int16RoughAdvancedConverter.cs
+++ b/Orm/Xtensive.Orm/Conversion/Internals/Int16RoughAdvancedConverter.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2008.02.08
 
-using System;
 
 namespace Xtensive.Conversion
 {
diff --git a/Orm/Xtensive.Orm/Conversion/Internals/Int32AdvancedConverter.cs b/Orm/Xtensive.Orm/Conversion/Internals/Int32AdvancedConverter.cs
index b1c6a4baa..23ca8caa0 100644
--- a/Orm/Xtensive.Orm/Conversion/Internals/Int32AdvancedConverter.cs
+++ b/Orm/Xtensive.Orm/Conversion/Internals/Int32AdvancedConverter.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2008.01.21
 
-using System;
 using System.Globalization;
 
 namespace Xtensive.Conversion
diff --git a/Orm/Xtensive.Orm/Conversion/Internals/Int32RoughAdvancedConverter.cs b/Orm/Xtensive.Orm/Conversion/Internals/Int32RoughAdvancedConverter.cs
index 6bd798c01..e1cbe352a 100644
--- a/Orm/Xtensive.Orm/Conversion/Internals/Int32RoughAdvancedConverter.cs
+++ b/Orm/Xtensive.Orm/Conversion/Internals/Int32RoughAdvancedConverter.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2008.02.08
 
-using System;
 
 namespace Xtensive.Conversion
 {
diff --git a/Orm/Xtensive.Orm/Conversion/Internals/Int64AdvancedConverter.cs b/Orm/Xtensive.Orm/Conversion/Internals/Int64AdvancedConverter.cs
index 2e2f5dd3a..1f191240a 100644
--- a/Orm/Xtensive.Orm/Conversion/Internals/Int64AdvancedConverter.cs
+++ b/Orm/Xtensive.Orm/Conversion/Internals/Int64AdvancedConverter.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2008.01.22
 
-using System;
 using System.Globalization;
 
 namespace Xtensive.Conversion
diff --git a/Orm/Xtensive.Orm/Conversion/Internals/Int64RoughAdvancedConverter.cs b/Orm/Xtensive.Orm/Conversion/Internals/Int64RoughAdvancedConverter.cs
index 3a1c786c3..5374e9e76 100644
--- a/Orm/Xtensive.Orm/Conversion/Internals/Int64RoughAdvancedConverter.cs
+++ b/Orm/Xtensive.Orm/Conversion/Internals/Int64RoughAdvancedConverter.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2008.02.08
 
-using System;
 
 namespace Xtensive.Conversion
 {
diff --git a/Orm/Xtensive.Orm/Conversion/Internals/NullableAdvancedConverterFactory.cs b/Orm/Xtensive.Orm/Conversion/Internals/NullableAdvancedConverterFactory.cs
index 5536d234d..f826ee71b 100644
--- a/Orm/Xtensive.Orm/Conversion/Internals/NullableAdvancedConverterFactory.cs
+++ b/Orm/Xtensive.Orm/Conversion/Internals/NullableAdvancedConverterFactory.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2008.02.14
 
-using System;
 using Xtensive.Reflection;
 
 namespace Xtensive.Conversion
diff --git a/Orm/Xtensive.Orm/Conversion/Internals/NullableForwardAdvancedConverter.cs b/Orm/Xtensive.Orm/Conversion/Internals/NullableForwardAdvancedConverter.cs
index 4bca7a5c8..2ffa8c913 100644
--- a/Orm/Xtensive.Orm/Conversion/Internals/NullableForwardAdvancedConverter.cs
+++ b/Orm/Xtensive.Orm/Conversion/Internals/NullableForwardAdvancedConverter.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2008.02.13
 
-using System;
 
 namespace Xtensive.Conversion
 {
diff --git a/Orm/Xtensive.Orm/Conversion/Internals/NullableNullableAdvancedConverter.cs b/Orm/Xtensive.Orm/Conversion/Internals/NullableNullableAdvancedConverter.cs
index 0a3a62950..9117e1b76 100644
--- a/Orm/Xtensive.Orm/Conversion/Internals/NullableNullableAdvancedConverter.cs
+++ b/Orm/Xtensive.Orm/Conversion/Internals/NullableNullableAdvancedConverter.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2008.02.13
 
-using System;
 
 namespace Xtensive.Conversion
 {
diff --git a/Orm/Xtensive.Orm/Conversion/Internals/NullableReverseAdvancedConverter.cs b/Orm/Xtensive.Orm/Conversion/Internals/NullableReverseAdvancedConverter.cs
index cff8e55ac..73ef7e87d 100644
--- a/Orm/Xtensive.Orm/Conversion/Internals/NullableReverseAdvancedConverter.cs
+++ b/Orm/Xtensive.Orm/Conversion/Internals/NullableReverseAdvancedConverter.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2008.02.13
 
-using System;
 
 namespace Xtensive.Conversion
 {
diff --git a/Orm/Xtensive.Orm/Conversion/Internals/ObjectAdvancedConverterFactory.cs b/Orm/Xtensive.Orm/Conversion/Internals/ObjectAdvancedConverterFactory.cs
index 600d8a691..feea09403 100644
--- a/Orm/Xtensive.Orm/Conversion/Internals/ObjectAdvancedConverterFactory.cs
+++ b/Orm/Xtensive.Orm/Conversion/Internals/ObjectAdvancedConverterFactory.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.03.08
 
-using System;
 using Xtensive.Reflection;
 
 namespace Xtensive.Conversion
diff --git a/Orm/Xtensive.Orm/Conversion/Internals/ObjectToBaseAdvancedConverter{TFrom, TTo}.cs b/Orm/Xtensive.Orm/Conversion/Internals/ObjectToBaseAdvancedConverter{TFrom, TTo}.cs
index 64361596b..bb70bce42 100644
--- a/Orm/Xtensive.Orm/Conversion/Internals/ObjectToBaseAdvancedConverter{TFrom, TTo}.cs	
+++ b/Orm/Xtensive.Orm/Conversion/Internals/ObjectToBaseAdvancedConverter{TFrom, TTo}.cs	
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.03.08
 
-using System;
 
 namespace Xtensive.Conversion
 {
diff --git a/Orm/Xtensive.Orm/Conversion/Internals/ObjectToDescendantAdvancedConverter{TFrom, TTo}.cs b/Orm/Xtensive.Orm/Conversion/Internals/ObjectToDescendantAdvancedConverter{TFrom, TTo}.cs
index 78f8c0a9c..d08003ca0 100644
--- a/Orm/Xtensive.Orm/Conversion/Internals/ObjectToDescendantAdvancedConverter{TFrom, TTo}.cs	
+++ b/Orm/Xtensive.Orm/Conversion/Internals/ObjectToDescendantAdvancedConverter{TFrom, TTo}.cs	
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.03.08
 
-using System;
 
 namespace Xtensive.Conversion
 {
diff --git a/Orm/Xtensive.Orm/Conversion/Internals/RoughAdvancedConverterBase.cs b/Orm/Xtensive.Orm/Conversion/Internals/RoughAdvancedConverterBase.cs
index 18cdcbf57..ef0bd2fb1 100644
--- a/Orm/Xtensive.Orm/Conversion/Internals/RoughAdvancedConverterBase.cs
+++ b/Orm/Xtensive.Orm/Conversion/Internals/RoughAdvancedConverterBase.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2008.02.08
 
-using System;
 
 namespace Xtensive.Conversion
 {
diff --git a/Orm/Xtensive.Orm/Conversion/Internals/SByteAdvancedConverter.cs b/Orm/Xtensive.Orm/Conversion/Internals/SByteAdvancedConverter.cs
index 5de87348f..8a888c48a 100644
--- a/Orm/Xtensive.Orm/Conversion/Internals/SByteAdvancedConverter.cs
+++ b/Orm/Xtensive.Orm/Conversion/Internals/SByteAdvancedConverter.cs
@@ -4,7 +4,6 @@
 // Created by: Roman Churakov
 // Created:    2008.01.22
 
-using System;
 using System.Globalization;
 
 namespace Xtensive.Conversion
diff --git a/Orm/Xtensive.Orm/Conversion/Internals/SByteRoughAdvancedConverter.cs b/Orm/Xtensive.Orm/Conversion/Internals/SByteRoughAdvancedConverter.cs
index 192c75ca5..af9972b8b 100644
--- a/Orm/Xtensive.Orm/Conversion/Internals/SByteRoughAdvancedConverter.cs
+++ b/Orm/Xtensive.Orm/Conversion/Internals/SByteRoughAdvancedConverter.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2008.02.08
 
-using System;
 
 namespace Xtensive.Conversion
 {
diff --git a/Orm/Xtensive.Orm/Conversion/Internals/SingleAdvancedConverter.cs b/Orm/Xtensive.Orm/Conversion/Internals/SingleAdvancedConverter.cs
index 149ce9b75..59b2f4cd1 100644
--- a/Orm/Xtensive.Orm/Conversion/Internals/SingleAdvancedConverter.cs
+++ b/Orm/Xtensive.Orm/Conversion/Internals/SingleAdvancedConverter.cs
@@ -4,7 +4,6 @@
 // Created by: Roman Churakov
 // Created:    2008.01.23
 
-using System;
 using System.Globalization;
 
 namespace Xtensive.Conversion
diff --git a/Orm/Xtensive.Orm/Conversion/Internals/SingleRoughAdvancedConverter.cs b/Orm/Xtensive.Orm/Conversion/Internals/SingleRoughAdvancedConverter.cs
index e58d3474f..4dcf824d0 100644
--- a/Orm/Xtensive.Orm/Conversion/Internals/SingleRoughAdvancedConverter.cs
+++ b/Orm/Xtensive.Orm/Conversion/Internals/SingleRoughAdvancedConverter.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2008.02.08
 
-using System;
 
 namespace Xtensive.Conversion
 {
diff --git a/Orm/Xtensive.Orm/Conversion/Internals/StrictAdvancedConverterBase.cs b/Orm/Xtensive.Orm/Conversion/Internals/StrictAdvancedConverterBase.cs
index 18792846e..dad53b1c9 100644
--- a/Orm/Xtensive.Orm/Conversion/Internals/StrictAdvancedConverterBase.cs
+++ b/Orm/Xtensive.Orm/Conversion/Internals/StrictAdvancedConverterBase.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2008.02.08
 
-using System;
 
 namespace Xtensive.Conversion
 {
diff --git a/Orm/Xtensive.Orm/Conversion/Internals/StringAdvancedConverter.cs b/Orm/Xtensive.Orm/Conversion/Internals/StringAdvancedConverter.cs
index 7288bca1c..9498e95f5 100644
--- a/Orm/Xtensive.Orm/Conversion/Internals/StringAdvancedConverter.cs
+++ b/Orm/Xtensive.Orm/Conversion/Internals/StringAdvancedConverter.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2008.01.21
 
-using System;
 
 namespace Xtensive.Conversion
 {
diff --git a/Orm/Xtensive.Orm/Conversion/Internals/StringRoughAdvancedConverter.cs b/Orm/Xtensive.Orm/Conversion/Internals/StringRoughAdvancedConverter.cs
index acb2dbdc7..243007c8f 100644
--- a/Orm/Xtensive.Orm/Conversion/Internals/StringRoughAdvancedConverter.cs
+++ b/Orm/Xtensive.Orm/Conversion/Internals/StringRoughAdvancedConverter.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2008.02.08
 
-using System;
 using System.Globalization;
 
 namespace Xtensive.Conversion
diff --git a/Orm/Xtensive.Orm/Conversion/Internals/StringRoughAdvancedConverter{T}.cs b/Orm/Xtensive.Orm/Conversion/Internals/StringRoughAdvancedConverter{T}.cs
index f2d6d2dc7..6be3d4fa8 100644
--- a/Orm/Xtensive.Orm/Conversion/Internals/StringRoughAdvancedConverter{T}.cs
+++ b/Orm/Xtensive.Orm/Conversion/Internals/StringRoughAdvancedConverter{T}.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2008.02.08
 
-using System;
 
 namespace Xtensive.Conversion
 {
diff --git a/Orm/Xtensive.Orm/Conversion/Internals/TimeSpanAdvancedConverter.cs b/Orm/Xtensive.Orm/Conversion/Internals/TimeSpanAdvancedConverter.cs
index a03b9d3a8..6230d9fb8 100644
--- a/Orm/Xtensive.Orm/Conversion/Internals/TimeSpanAdvancedConverter.cs
+++ b/Orm/Xtensive.Orm/Conversion/Internals/TimeSpanAdvancedConverter.cs
@@ -4,7 +4,6 @@
 // Created by: Elena Vakhtina
 // Created:    2008.11.11
 
-using System;
 
 namespace Xtensive.Conversion
 {
diff --git a/Orm/Xtensive.Orm/Conversion/Internals/TimeSpanRoughAdvancedConverter.cs b/Orm/Xtensive.Orm/Conversion/Internals/TimeSpanRoughAdvancedConverter.cs
index 044131728..c0fa1a522 100644
--- a/Orm/Xtensive.Orm/Conversion/Internals/TimeSpanRoughAdvancedConverter.cs
+++ b/Orm/Xtensive.Orm/Conversion/Internals/TimeSpanRoughAdvancedConverter.cs
@@ -4,7 +4,6 @@
 // Created by: Elena Vakhtina
 // Created:    2008.11.12
 
-using System;
 
 namespace Xtensive.Conversion
 {
diff --git a/Orm/Xtensive.Orm/Conversion/Internals/TypeAdvancedConverter.cs b/Orm/Xtensive.Orm/Conversion/Internals/TypeAdvancedConverter.cs
index 0241bfe76..3cddabacc 100644
--- a/Orm/Xtensive.Orm/Conversion/Internals/TypeAdvancedConverter.cs
+++ b/Orm/Xtensive.Orm/Conversion/Internals/TypeAdvancedConverter.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.08.26
 
-using System;
 
 namespace Xtensive.Conversion
 {
diff --git a/Orm/Xtensive.Orm/Conversion/Internals/UInt16AdvancedConverter.cs b/Orm/Xtensive.Orm/Conversion/Internals/UInt16AdvancedConverter.cs
index a50db528a..6e7407cab 100644
--- a/Orm/Xtensive.Orm/Conversion/Internals/UInt16AdvancedConverter.cs
+++ b/Orm/Xtensive.Orm/Conversion/Internals/UInt16AdvancedConverter.cs
@@ -4,7 +4,6 @@
 // Created by: Roman Churakov
 // Created:    2008.01.23
 
-using System;
 using System.Globalization;
 
 namespace Xtensive.Conversion
diff --git a/Orm/Xtensive.Orm/Conversion/Internals/UInt16RoughAdvancedConverter.cs b/Orm/Xtensive.Orm/Conversion/Internals/UInt16RoughAdvancedConverter.cs
index 25630838d..5250e18de 100644
--- a/Orm/Xtensive.Orm/Conversion/Internals/UInt16RoughAdvancedConverter.cs
+++ b/Orm/Xtensive.Orm/Conversion/Internals/UInt16RoughAdvancedConverter.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2008.02.08
 
-using System;
 
 namespace Xtensive.Conversion
 {
diff --git a/Orm/Xtensive.Orm/Conversion/Internals/UInt32AdvancedConverter.cs b/Orm/Xtensive.Orm/Conversion/Internals/UInt32AdvancedConverter.cs
index 6a32e8d6e..eba1f879d 100644
--- a/Orm/Xtensive.Orm/Conversion/Internals/UInt32AdvancedConverter.cs
+++ b/Orm/Xtensive.Orm/Conversion/Internals/UInt32AdvancedConverter.cs
@@ -4,7 +4,6 @@
 // Created by: Roman Churakov
 // Created:    2008.01.23
 
-using System;
 using System.Globalization;
 
 namespace Xtensive.Conversion
diff --git a/Orm/Xtensive.Orm/Conversion/Internals/UInt32RoughAdvancedConverter.cs b/Orm/Xtensive.Orm/Conversion/Internals/UInt32RoughAdvancedConverter.cs
index 922127759..5623e6f33 100644
--- a/Orm/Xtensive.Orm/Conversion/Internals/UInt32RoughAdvancedConverter.cs
+++ b/Orm/Xtensive.Orm/Conversion/Internals/UInt32RoughAdvancedConverter.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2008.02.08
 
-using System;
 
 namespace Xtensive.Conversion
 {
diff --git a/Orm/Xtensive.Orm/Conversion/Internals/UInt64AdvancedConverter.cs b/Orm/Xtensive.Orm/Conversion/Internals/UInt64AdvancedConverter.cs
index 0391cf95d..87d38f227 100644
--- a/Orm/Xtensive.Orm/Conversion/Internals/UInt64AdvancedConverter.cs
+++ b/Orm/Xtensive.Orm/Conversion/Internals/UInt64AdvancedConverter.cs
@@ -4,7 +4,6 @@
 // Created by: Roman Churakov
 // Created:    2008.01.23
 
-using System;
 using System.Globalization;
 
 namespace Xtensive.Conversion
diff --git a/Orm/Xtensive.Orm/Conversion/Internals/UInt64RoughAdvancedConverter.cs b/Orm/Xtensive.Orm/Conversion/Internals/UInt64RoughAdvancedConverter.cs
index e2878dc4f..834a77845 100644
--- a/Orm/Xtensive.Orm/Conversion/Internals/UInt64RoughAdvancedConverter.cs
+++ b/Orm/Xtensive.Orm/Conversion/Internals/UInt64RoughAdvancedConverter.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2008.02.08
 
-using System;
 
 namespace Xtensive.Conversion
 {
diff --git a/Orm/Xtensive.Orm/Conversion/WrappingAdvancedConverter.cs b/Orm/Xtensive.Orm/Conversion/WrappingAdvancedConverter.cs
index 51eef3c4e..83f0c5f50 100644
--- a/Orm/Xtensive.Orm/Conversion/WrappingAdvancedConverter.cs
+++ b/Orm/Xtensive.Orm/Conversion/WrappingAdvancedConverter.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2008.02.13
 
-using System;
 
 namespace Xtensive.Conversion
 {
diff --git a/Orm/Xtensive.Orm/Core/AliasGenerator.cs b/Orm/Xtensive.Orm/Core/AliasGenerator.cs
index 8550343d4..f981de937 100644
--- a/Orm/Xtensive.Orm/Core/AliasGenerator.cs
+++ b/Orm/Xtensive.Orm/Core/AliasGenerator.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.02.10
 
-using System;
 
 namespace Xtensive.Core
 {
diff --git a/Orm/Xtensive.Orm/Core/ArgumentValidator.cs b/Orm/Xtensive.Orm/Core/ArgumentValidator.cs
index d8da37ab0..0ee61508b 100644
--- a/Orm/Xtensive.Orm/Core/ArgumentValidator.cs
+++ b/Orm/Xtensive.Orm/Core/ArgumentValidator.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2007.10.01
 
-using System;
 using System.Runtime.CompilerServices;
 using JetBrains.Annotations;
 using Xtensive.Comparison;
diff --git a/Orm/Xtensive.Orm/Core/AssociateProvider.cs b/Orm/Xtensive.Orm/Core/AssociateProvider.cs
index 076da2971..5226d5f51 100644
--- a/Orm/Xtensive.Orm/Core/AssociateProvider.cs
+++ b/Orm/Xtensive.Orm/Core/AssociateProvider.cs
@@ -4,15 +4,12 @@
 // Created by: Alexey Gamzov
 // Created:    2008.01.18
 
-using System;
-using System.Collections.Generic;
 using System.Collections.Concurrent;
 using System.Diagnostics;
 using System.Reflection;
 using System.Runtime.Serialization;
 using System.Security;
 using System.Text;
-using System.Threading;
 using Xtensive.Comparison;
 
 using Xtensive.Reflection;
diff --git a/Orm/Xtensive.Orm/Core/AsyncFutureResult.cs b/Orm/Xtensive.Orm/Core/AsyncFutureResult.cs
index c48216f33..c70728079 100644
--- a/Orm/Xtensive.Orm/Core/AsyncFutureResult.cs
+++ b/Orm/Xtensive.Orm/Core/AsyncFutureResult.cs
@@ -4,9 +4,7 @@
 // Created by: Denis Krjuchkov
 // Created:    2014.03.12
 
-using System;
 using Xtensive.Orm.Logging;
-using System.Threading.Tasks;
 
 
 namespace Xtensive.Core
diff --git a/Orm/Xtensive.Orm/Core/ConfigurationCollection.cs b/Orm/Xtensive.Orm/Core/ConfigurationCollection.cs
index 3300408d7..6332b423c 100644
--- a/Orm/Xtensive.Orm/Core/ConfigurationCollection.cs
+++ b/Orm/Xtensive.Orm/Core/ConfigurationCollection.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2008.08.07
 
-using System.Collections.Generic;
 using System.Configuration;
 
 namespace Xtensive.Core
diff --git a/Orm/Xtensive.Orm/Core/Context.cs b/Orm/Xtensive.Orm/Core/Context.cs
index 25bda7e2c..1031f0c47 100644
--- a/Orm/Xtensive.Orm/Core/Context.cs
+++ b/Orm/Xtensive.Orm/Core/Context.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2008.01.15
 
-using System;
 using System.Diagnostics;
 
 namespace Xtensive.Core
diff --git a/Orm/Xtensive.Orm/Core/Direction.cs b/Orm/Xtensive.Orm/Core/Direction.cs
index be1ab678b..b2d3994e6 100644
--- a/Orm/Xtensive.Orm/Core/Direction.cs
+++ b/Orm/Xtensive.Orm/Core/Direction.cs
@@ -4,7 +4,6 @@
 // Created by: Nick Svetlov
 // Created:    2007.09.10
 
-using System;
 
 namespace Xtensive.Core
 {
diff --git a/Orm/Xtensive.Orm/Core/Disposable.cs b/Orm/Xtensive.Orm/Core/Disposable.cs
index 8b1a5adfc..ac5af28f8 100644
--- a/Orm/Xtensive.Orm/Core/Disposable.cs
+++ b/Orm/Xtensive.Orm/Core/Disposable.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2007.10.03
 
-using System;
 
 
 namespace Xtensive.Core
diff --git a/Orm/Xtensive.Orm/Core/DisposableSet.cs b/Orm/Xtensive.Orm/Core/DisposableSet.cs
index 0b2e88ee0..f1b295b4f 100644
--- a/Orm/Xtensive.Orm/Core/DisposableSet.cs
+++ b/Orm/Xtensive.Orm/Core/DisposableSet.cs
@@ -4,10 +4,7 @@
 // Created by: Alex Yakunin
 // Created:    2007.12.29
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
-using System.Threading.Tasks;
 using Xtensive.Core;
 
 
diff --git a/Orm/Xtensive.Orm/Core/Disposable{T1,T2}.cs b/Orm/Xtensive.Orm/Core/Disposable{T1,T2}.cs
index b33abe1c7..bbc009237 100644
--- a/Orm/Xtensive.Orm/Core/Disposable{T1,T2}.cs
+++ b/Orm/Xtensive.Orm/Core/Disposable{T1,T2}.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2007.10.03
 
-using System;
 
 
 namespace Xtensive.Core
diff --git a/Orm/Xtensive.Orm/Core/Disposable{T}.cs b/Orm/Xtensive.Orm/Core/Disposable{T}.cs
index 81c91206c..1215954a8 100644
--- a/Orm/Xtensive.Orm/Core/Disposable{T}.cs
+++ b/Orm/Xtensive.Orm/Core/Disposable{T}.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2007.10.03
 
-using System;
 
 
 namespace Xtensive.Core
diff --git a/Orm/Xtensive.Orm/Core/EnumeratorExtensions.cs b/Orm/Xtensive.Orm/Core/EnumeratorExtensions.cs
index b44745fff..e46005e7a 100644
--- a/Orm/Xtensive.Orm/Core/EnumeratorExtensions.cs
+++ b/Orm/Xtensive.Orm/Core/EnumeratorExtensions.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2019.06.24
 
-using System.Collections.Generic;
 
 namespace Xtensive.Core
 {
diff --git a/Orm/Xtensive.Orm/Core/ExceptionAggregator.cs b/Orm/Xtensive.Orm/Core/ExceptionAggregator.cs
index 5a7dd6b34..e832a2413 100644
--- a/Orm/Xtensive.Orm/Core/ExceptionAggregator.cs
+++ b/Orm/Xtensive.Orm/Core/ExceptionAggregator.cs
@@ -4,12 +4,8 @@
 // Created by: Alex Yakunin
 // Created:    2008.07.04
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
 using System.Diagnostics;
-using System.Linq;
-using System.Threading.Tasks;
 using Xtensive.Collections;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Core/Exceptions.cs b/Orm/Xtensive.Orm/Core/Exceptions.cs
index 18a80be3a..0d5555d42 100644
--- a/Orm/Xtensive.Orm/Core/Exceptions.cs
+++ b/Orm/Xtensive.Orm/Core/Exceptions.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2007.10.03
 
-using System;
 using System.Linq.Expressions;
 using JetBrains.Annotations;
 using Xtensive.Orm.Logging;
diff --git a/Orm/Xtensive.Orm/Core/Exceptions/ActivationException.cs b/Orm/Xtensive.Orm/Core/Exceptions/ActivationException.cs
index 12a737343..8e11af8ea 100644
--- a/Orm/Xtensive.Orm/Core/Exceptions/ActivationException.cs
+++ b/Orm/Xtensive.Orm/Core/Exceptions/ActivationException.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2010.01.30
 
-using System;
 using System.Runtime.Serialization;
 
 using Xtensive.IoC;
diff --git a/Orm/Xtensive.Orm/Core/Exceptions/AggregateException.cs b/Orm/Xtensive.Orm/Core/Exceptions/AggregateException.cs
index 928e62745..0443f0892 100644
--- a/Orm/Xtensive.Orm/Core/Exceptions/AggregateException.cs
+++ b/Orm/Xtensive.Orm/Core/Exceptions/AggregateException.cs
@@ -4,13 +4,10 @@
 // Created by: Alex Yakunin
 // Created:    2008.07.03
 
-using System;
-using System.Collections.Generic;
 using System.Diagnostics;
 using System.Runtime.Serialization;
 using System.Security;
 using System.Text;
-using System.Linq;
 
 namespace Xtensive.Core
 {
diff --git a/Orm/Xtensive.Orm/Core/Exceptions/InstanceIsLockedException.cs b/Orm/Xtensive.Orm/Core/Exceptions/InstanceIsLockedException.cs
index 17f8ec164..c9267ac89 100644
--- a/Orm/Xtensive.Orm/Core/Exceptions/InstanceIsLockedException.cs
+++ b/Orm/Xtensive.Orm/Core/Exceptions/InstanceIsLockedException.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2007.06.08
 
-using System;
 using System.Runtime.Serialization;
 
 
diff --git a/Orm/Xtensive.Orm/Core/Extensions/ArrayExtensions.cs b/Orm/Xtensive.Orm/Core/Extensions/ArrayExtensions.cs
index 6bcfc1710..12a90a9fb 100644
--- a/Orm/Xtensive.Orm/Core/Extensions/ArrayExtensions.cs
+++ b/Orm/Xtensive.Orm/Core/Extensions/ArrayExtensions.cs
@@ -5,8 +5,6 @@
 // Reimplemented by: Dmitri Maximov
 // Created:    2007.07.04
 
-using System;
-using System.Collections.Generic;
 using Xtensive.Comparison;
 using Xtensive.Core;
 using Xtensive.Reflection;
diff --git a/Orm/Xtensive.Orm/Core/Extensions/CollectionExtensions.cs b/Orm/Xtensive.Orm/Core/Extensions/CollectionExtensions.cs
index 8a34b071c..744f4ad47 100644
--- a/Orm/Xtensive.Orm/Core/Extensions/CollectionExtensions.cs
+++ b/Orm/Xtensive.Orm/Core/Extensions/CollectionExtensions.cs
@@ -5,9 +5,6 @@
 // Reimplemented by: Dmitri Maximov
 // Created:    2007.07.04
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Core;
 
 namespace Xtensive.Core
diff --git a/Orm/Xtensive.Orm/Core/Extensions/DelegateBindExtensions.cs b/Orm/Xtensive.Orm/Core/Extensions/DelegateBindExtensions.cs
index eed2a6c16..d35f4620a 100644
--- a/Orm/Xtensive.Orm/Core/Extensions/DelegateBindExtensions.cs
+++ b/Orm/Xtensive.Orm/Core/Extensions/DelegateBindExtensions.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.05.06
 
-using System;
 
 namespace Xtensive.Core
 {
diff --git a/Orm/Xtensive.Orm/Core/Extensions/DisposableExtensions.cs b/Orm/Xtensive.Orm/Core/Extensions/DisposableExtensions.cs
index 22f6c1c14..69d8d7b09 100644
--- a/Orm/Xtensive.Orm/Core/Extensions/DisposableExtensions.cs
+++ b/Orm/Xtensive.Orm/Core/Extensions/DisposableExtensions.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.05.14
 
-using System;
-using System.Threading.Tasks;
 using Xtensive.Core;
 
 namespace Xtensive.Core
diff --git a/Orm/Xtensive.Orm/Core/Extensions/EnumerableExtensions.cs b/Orm/Xtensive.Orm/Core/Extensions/EnumerableExtensions.cs
index 06d6329da..9c4f9b545 100644
--- a/Orm/Xtensive.Orm/Core/Extensions/EnumerableExtensions.cs
+++ b/Orm/Xtensive.Orm/Core/Extensions/EnumerableExtensions.cs
@@ -4,14 +4,9 @@
 // Created by: Alex Yakunin
 // Created:    2008.05.16
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
-using System.Linq;
 using System.Runtime.CompilerServices;
 using System.Text;
-using System.Threading;
-using System.Threading.Tasks;
 using Xtensive.Collections;
 using Xtensive.Collections.Graphs;
 using Xtensive.Orm;
diff --git a/Orm/Xtensive.Orm/Core/Extensions/ExpressionCompileExtensions.cs b/Orm/Xtensive.Orm/Core/Extensions/ExpressionCompileExtensions.cs
index bc1c92ac2..469881a10 100644
--- a/Orm/Xtensive.Orm/Core/Extensions/ExpressionCompileExtensions.cs
+++ b/Orm/Xtensive.Orm/Core/Extensions/ExpressionCompileExtensions.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.05.07
 
-using System;
 using System.Linq.Expressions;
 using Xtensive.Linq;
 
diff --git a/Orm/Xtensive.Orm/Core/Extensions/ExpressionExtensions.cs b/Orm/Xtensive.Orm/Core/Extensions/ExpressionExtensions.cs
index 2196f55ff..4ed63c203 100644
--- a/Orm/Xtensive.Orm/Core/Extensions/ExpressionExtensions.cs
+++ b/Orm/Xtensive.Orm/Core/Extensions/ExpressionExtensions.cs
@@ -4,14 +4,12 @@
 // Created by: Alexis Kochetov
 // Created:    2009.04.21
 
-using System;
 using System.Linq.Expressions;
 using System.Reflection;
 using Xtensive.Linq;
 using Xtensive.Linq.SerializableExpressions;
 using Xtensive.Linq.SerializableExpressions.Internals;
 
-using System.Linq;
 using Xtensive.Reflection;
 using System.Collections.Concurrent;
 
diff --git a/Orm/Xtensive.Orm/Core/Extensions/HasServicesExtensions.cs b/Orm/Xtensive.Orm/Core/Extensions/HasServicesExtensions.cs
index 4e65fb95e..998442c61 100644
--- a/Orm/Xtensive.Orm/Core/Extensions/HasServicesExtensions.cs
+++ b/Orm/Xtensive.Orm/Core/Extensions/HasServicesExtensions.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.07.15
 
-using System;
 using Xtensive.Core;
 using Xtensive.Reflection;
 
diff --git a/Orm/Xtensive.Orm/Core/Extensions/ListExtensions.cs b/Orm/Xtensive.Orm/Core/Extensions/ListExtensions.cs
index d50fdcb84..9d2c6fb22 100644
--- a/Orm/Xtensive.Orm/Core/Extensions/ListExtensions.cs
+++ b/Orm/Xtensive.Orm/Core/Extensions/ListExtensions.cs
@@ -5,9 +5,7 @@
 // Reimplemented by: Dmitri Maximov
 // Created:    2007.07.04
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
 
 
 namespace Xtensive.Core
diff --git a/Orm/Xtensive.Orm/Core/Extensions/ServiceContainerExtensions.cs b/Orm/Xtensive.Orm/Core/Extensions/ServiceContainerExtensions.cs
index 6160475bf..2c5a86e6e 100644
--- a/Orm/Xtensive.Orm/Core/Extensions/ServiceContainerExtensions.cs
+++ b/Orm/Xtensive.Orm/Core/Extensions/ServiceContainerExtensions.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2010.02.02
 
-using System;
 using JetBrains.Annotations;
 using Xtensive.Reflection;
 using Xtensive.IoC;
diff --git a/Orm/Xtensive.Orm/Core/Extensions/StringBuilderExtensions.cs b/Orm/Xtensive.Orm/Core/Extensions/StringBuilderExtensions.cs
index 741b692b6..593e0af1a 100644
--- a/Orm/Xtensive.Orm/Core/Extensions/StringBuilderExtensions.cs
+++ b/Orm/Xtensive.Orm/Core/Extensions/StringBuilderExtensions.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Kofman
 // Created:    2008.07.30
 
-using System;
 using System.Text;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Core/Extensions/StringExtensions.cs b/Orm/Xtensive.Orm/Core/Extensions/StringExtensions.cs
index 9548948a0..a8ebddaee 100644
--- a/Orm/Xtensive.Orm/Core/Extensions/StringExtensions.cs
+++ b/Orm/Xtensive.Orm/Core/Extensions/StringExtensions.cs
@@ -4,9 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2008.07.18
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Text;
 using System.Text.RegularExpressions;
 
diff --git a/Orm/Xtensive.Orm/Core/FutureResult.cs b/Orm/Xtensive.Orm/Core/FutureResult.cs
index 5e9cf5f35..7d3899b1b 100644
--- a/Orm/Xtensive.Orm/Core/FutureResult.cs
+++ b/Orm/Xtensive.Orm/Core/FutureResult.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.03.15
 
-using System;
-using System.Threading.Tasks;
 
 namespace Xtensive.Core
 {
diff --git a/Orm/Xtensive.Orm/Core/HasVersion{TValue,TVersion}.cs b/Orm/Xtensive.Orm/Core/HasVersion{TValue,TVersion}.cs
index 630107db8..9fb4e313f 100644
--- a/Orm/Xtensive.Orm/Core/HasVersion{TValue,TVersion}.cs
+++ b/Orm/Xtensive.Orm/Core/HasVersion{TValue,TVersion}.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Ustinov
 // Created:    2007.06.01
 
-using System;
 using System.Diagnostics;
 using Xtensive.Comparison;
 
diff --git a/Orm/Xtensive.Orm/Core/InheritableScope.cs b/Orm/Xtensive.Orm/Core/InheritableScope.cs
index 3e5ca969b..938891bb2 100644
--- a/Orm/Xtensive.Orm/Core/InheritableScope.cs
+++ b/Orm/Xtensive.Orm/Core/InheritableScope.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2009.05.05
 
-using System;
 using System.Security;
 
 
diff --git a/Orm/Xtensive.Orm/Core/Interfaces/IContext.cs b/Orm/Xtensive.Orm/Core/Interfaces/IContext.cs
index c09293b61..26aca0b3f 100644
--- a/Orm/Xtensive.Orm/Core/Interfaces/IContext.cs
+++ b/Orm/Xtensive.Orm/Core/Interfaces/IContext.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2007.12.31
 
-using System;
 
 namespace Xtensive.Core
 {
diff --git a/Orm/Xtensive.Orm/Core/Interfaces/IContext{TScope}.cs b/Orm/Xtensive.Orm/Core/Interfaces/IContext{TScope}.cs
index f29a6e2e6..4c89fecf9 100644
--- a/Orm/Xtensive.Orm/Core/Interfaces/IContext{TScope}.cs
+++ b/Orm/Xtensive.Orm/Core/Interfaces/IContext{TScope}.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2007.12.31
 
-using System;
 
 namespace Xtensive.Core
 {
diff --git a/Orm/Xtensive.Orm/Core/Interfaces/IHasServices.cs b/Orm/Xtensive.Orm/Core/Interfaces/IHasServices.cs
index 7391d6e38..211ffe57a 100644
--- a/Orm/Xtensive.Orm/Core/Interfaces/IHasServices.cs
+++ b/Orm/Xtensive.Orm/Core/Interfaces/IHasServices.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.07.15
 
-using System;
 
 namespace Xtensive.Core
 {
diff --git a/Orm/Xtensive.Orm/Core/Interfaces/IIdentified.cs b/Orm/Xtensive.Orm/Core/Interfaces/IIdentified.cs
index 5904aa056..684bcab49 100644
--- a/Orm/Xtensive.Orm/Core/Interfaces/IIdentified.cs
+++ b/Orm/Xtensive.Orm/Core/Interfaces/IIdentified.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2007.05.01
 
-using System;
 
 namespace Xtensive.Core
 {
diff --git a/Orm/Xtensive.Orm/Core/Internals/ValueStringBuilder.cs b/Orm/Xtensive.Orm/Core/Internals/ValueStringBuilder.cs
index 1fad96af0..50c60a716 100644
--- a/Orm/Xtensive.Orm/Core/Internals/ValueStringBuilder.cs
+++ b/Orm/Xtensive.Orm/Core/Internals/ValueStringBuilder.cs
@@ -5,7 +5,6 @@
 // + re-structured to fit project rules
 // + formatting rules applied
 
-using System;
 using System.Buffers;
 using System.Diagnostics;
 using System.Runtime.CompilerServices;
diff --git a/Orm/Xtensive.Orm/Core/JoiningDisposable.cs b/Orm/Xtensive.Orm/Core/JoiningDisposable.cs
index 9304c86c2..2f701a67b 100644
--- a/Orm/Xtensive.Orm/Core/JoiningDisposable.cs
+++ b/Orm/Xtensive.Orm/Core/JoiningDisposable.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2009.03.27
 
-using System;
 using System.Diagnostics;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Core/LockableBase.cs b/Orm/Xtensive.Orm/Core/LockableBase.cs
index 48cb59a6d..1b4d74708 100644
--- a/Orm/Xtensive.Orm/Core/LockableBase.cs
+++ b/Orm/Xtensive.Orm/Core/LockableBase.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2007.11.22
 
-using System;
 using System.Diagnostics;
 
 
diff --git a/Orm/Xtensive.Orm/Core/MatchType.cs b/Orm/Xtensive.Orm/Core/MatchType.cs
index 3d8d09bc2..94d523c86 100644
--- a/Orm/Xtensive.Orm/Core/MatchType.cs
+++ b/Orm/Xtensive.Orm/Core/MatchType.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2007.12.25
 
-using System;
 
 namespace Xtensive.Core
 {
diff --git a/Orm/Xtensive.Orm/Core/MethodCacheBase.cs b/Orm/Xtensive.Orm/Core/MethodCacheBase.cs
index 6506dd2e3..9932ece5f 100644
--- a/Orm/Xtensive.Orm/Core/MethodCacheBase.cs
+++ b/Orm/Xtensive.Orm/Core/MethodCacheBase.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.02.10
 
-using System;
 using System.Runtime.Serialization;
 using System.Security;
 using System.Security.Permissions;
diff --git a/Orm/Xtensive.Orm/Core/Pair{TFirst,TSecond}.cs b/Orm/Xtensive.Orm/Core/Pair{TFirst,TSecond}.cs
index af240475f..969b4dd1a 100644
--- a/Orm/Xtensive.Orm/Core/Pair{TFirst,TSecond}.cs
+++ b/Orm/Xtensive.Orm/Core/Pair{TFirst,TSecond}.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Ustinov
 // Created:    2007.06.01
 
-using System;
 using System.Diagnostics;
 using Xtensive.Comparison;
 
diff --git a/Orm/Xtensive.Orm/Core/Pair{T}.cs b/Orm/Xtensive.Orm/Core/Pair{T}.cs
index 96a40c852..acdde4370 100644
--- a/Orm/Xtensive.Orm/Core/Pair{T}.cs
+++ b/Orm/Xtensive.Orm/Core/Pair{T}.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Ustinov
 // Created:    2007.06.01
 
-using System;
 using System.Diagnostics;
 using Xtensive.Comparison;
 
diff --git a/Orm/Xtensive.Orm/Core/ParameterContext.cs b/Orm/Xtensive.Orm/Core/ParameterContext.cs
index 2829d67ee..9d7e5d19a 100644
--- a/Orm/Xtensive.Orm/Core/ParameterContext.cs
+++ b/Orm/Xtensive.Orm/Core/ParameterContext.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Kofman
 // Created:    2008.08.14
 
-using System;
-using System.Collections.Generic;
 using System.Diagnostics;
 using Tuple = Xtensive.Tuples.Tuple;
 
diff --git a/Orm/Xtensive.Orm/Core/Parameter{TValue}.cs b/Orm/Xtensive.Orm/Core/Parameter{TValue}.cs
index fcafb9afa..c3823011a 100644
--- a/Orm/Xtensive.Orm/Core/Parameter{TValue}.cs
+++ b/Orm/Xtensive.Orm/Core/Parameter{TValue}.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Kofman
 // Created:    2008.08.14
 
-using System;
 using System.Diagnostics;
 
 namespace Xtensive.Core
diff --git a/Orm/Xtensive.Orm/Core/Scope.cs b/Orm/Xtensive.Orm/Core/Scope.cs
index e67de0408..9632cfec2 100644
--- a/Orm/Xtensive.Orm/Core/Scope.cs
+++ b/Orm/Xtensive.Orm/Core/Scope.cs
@@ -4,11 +4,9 @@
 // Created by: Dmitri Maximov
 // Created:    2007.09.27
 
-using System;
 using System.Diagnostics;
 using System.Runtime.ExceptionServices;
 using System.Security;
-using System.Threading;
 
 
 namespace Xtensive.Core
diff --git a/Orm/Xtensive.Orm/Core/Segment.cs b/Orm/Xtensive.Orm/Core/Segment.cs
index a04902dcd..da948d86a 100644
--- a/Orm/Xtensive.Orm/Core/Segment.cs
+++ b/Orm/Xtensive.Orm/Core/Segment.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2008.05.30
 
-using System;
 using System.Diagnostics;
 using Xtensive.Arithmetic;
 using Xtensive.Comparison;
diff --git a/Orm/Xtensive.Orm/Core/SimpleScope.cs b/Orm/Xtensive.Orm/Core/SimpleScope.cs
index d758f6b23..43df93d9d 100644
--- a/Orm/Xtensive.Orm/Core/SimpleScope.cs
+++ b/Orm/Xtensive.Orm/Core/SimpleScope.cs
@@ -4,10 +4,8 @@
 // Created by: Dmitri Maximov
 // Created:    2007.09.27
 
-using System;
 using System.Diagnostics;
 using System.Security;
-using System.Threading;
 
 
 namespace Xtensive.Core
diff --git a/Orm/Xtensive.Orm/Core/SynchronousFutureResult.cs b/Orm/Xtensive.Orm/Core/SynchronousFutureResult.cs
index b517a8cef..023dd567f 100644
--- a/Orm/Xtensive.Orm/Core/SynchronousFutureResult.cs
+++ b/Orm/Xtensive.Orm/Core/SynchronousFutureResult.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2014.03.12
 
-using System;
-using System.Threading.Tasks;
 
 namespace Xtensive.Core
 {
diff --git a/Orm/Xtensive.Orm/InternalLogs.cs b/Orm/Xtensive.Orm/InternalLogs.cs
index 11dc9ad25..6b471c7f9 100644
--- a/Orm/Xtensive.Orm/InternalLogs.cs
+++ b/Orm/Xtensive.Orm/InternalLogs.cs
@@ -1,4 +1,3 @@
-using System;
 using System.Diagnostics;
 using Xtensive.Orm.Logging;
 using JetBrains.Annotations;
diff --git a/Orm/Xtensive.Orm/IoC/Attributes/ServiceAttribute.cs b/Orm/Xtensive.Orm/IoC/Attributes/ServiceAttribute.cs
index 8298e9f60..a6826e9fa 100644
--- a/Orm/Xtensive.Orm/IoC/Attributes/ServiceAttribute.cs
+++ b/Orm/Xtensive.Orm/IoC/Attributes/ServiceAttribute.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2010.01.30
 
-using System;
 
 
 namespace Xtensive.IoC
diff --git a/Orm/Xtensive.Orm/IoC/Attributes/ServiceConstructorAttribute.cs b/Orm/Xtensive.Orm/IoC/Attributes/ServiceConstructorAttribute.cs
index bb9cde220..579cac5da 100644
--- a/Orm/Xtensive.Orm/IoC/Attributes/ServiceConstructorAttribute.cs
+++ b/Orm/Xtensive.Orm/IoC/Attributes/ServiceConstructorAttribute.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2010.01.30
 
-using System;
 
 
 namespace Xtensive.IoC
diff --git a/Orm/Xtensive.Orm/IoC/Configuration/ContainerElement.cs b/Orm/Xtensive.Orm/IoC/Configuration/ContainerElement.cs
index bb48be553..44e13fde1 100644
--- a/Orm/Xtensive.Orm/IoC/Configuration/ContainerElement.cs
+++ b/Orm/Xtensive.Orm/IoC/Configuration/ContainerElement.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2009.12.16
 
-using System;
 using System.Configuration;
 using Xtensive.Collections;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/IoC/Configuration/ServiceRegistrationElement.cs b/Orm/Xtensive.Orm/IoC/Configuration/ServiceRegistrationElement.cs
index 1f643baa7..fe6016f71 100644
--- a/Orm/Xtensive.Orm/IoC/Configuration/ServiceRegistrationElement.cs
+++ b/Orm/Xtensive.Orm/IoC/Configuration/ServiceRegistrationElement.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2009.12.15
 
-using System;
 using System.Configuration;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/IoC/Interfaces/IServiceContainer.cs b/Orm/Xtensive.Orm/IoC/Interfaces/IServiceContainer.cs
index 6fd4a2bf7..bf5351046 100644
--- a/Orm/Xtensive.Orm/IoC/Interfaces/IServiceContainer.cs
+++ b/Orm/Xtensive.Orm/IoC/Interfaces/IServiceContainer.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2010.01.30
 
-using System;
-using System.Collections.Generic;
 using Xtensive.Core;
 
 namespace Xtensive.IoC
diff --git a/Orm/Xtensive.Orm/IoC/Internals/DefaultServiceContainer.cs b/Orm/Xtensive.Orm/IoC/Internals/DefaultServiceContainer.cs
index a80b9d361..153c6b76e 100644
--- a/Orm/Xtensive.Orm/IoC/Internals/DefaultServiceContainer.cs
+++ b/Orm/Xtensive.Orm/IoC/Internals/DefaultServiceContainer.cs
@@ -4,10 +4,7 @@
 // Created by: Alex Yakunin
 // Created:    2010.01.30
 
-using System;
-using System.Collections.Generic;
 using System.Collections.Concurrent;
-using System.Linq;
 using System.Reflection;
 using Xtensive.Collections;
 
diff --git a/Orm/Xtensive.Orm/IoC/Internals/ServiceTypeRegistrationProcessor.cs b/Orm/Xtensive.Orm/IoC/Internals/ServiceTypeRegistrationProcessor.cs
index f67056ee0..8a18c97d9 100644
--- a/Orm/Xtensive.Orm/IoC/Internals/ServiceTypeRegistrationProcessor.cs
+++ b/Orm/Xtensive.Orm/IoC/Internals/ServiceTypeRegistrationProcessor.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2010.01.30
 
-using System;
 using Xtensive.Collections;
 using Xtensive.Reflection;
 
diff --git a/Orm/Xtensive.Orm/IoC/ServiceContainer.cs b/Orm/Xtensive.Orm/IoC/ServiceContainer.cs
index 50575b5f0..183fd46dd 100644
--- a/Orm/Xtensive.Orm/IoC/ServiceContainer.cs
+++ b/Orm/Xtensive.Orm/IoC/ServiceContainer.cs
@@ -4,11 +4,8 @@
 // Created by: Dmitri Maximov
 // Created:    2009.10.12
 
-using System;
 using System.Collections.Concurrent;
-using System.Collections.Generic;
 using System.Configuration;
-using System.Linq;
 using System.Reflection;
 using Xtensive.Collections;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/IoC/ServiceContainerBase.cs b/Orm/Xtensive.Orm/IoC/ServiceContainerBase.cs
index ffe70b4bf..0424495e1 100644
--- a/Orm/Xtensive.Orm/IoC/ServiceContainerBase.cs
+++ b/Orm/Xtensive.Orm/IoC/ServiceContainerBase.cs
@@ -4,9 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2010.01.30
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Core;
 using Xtensive.Reflection;
 
diff --git a/Orm/Xtensive.Orm/IoC/ServiceRegistration.cs b/Orm/Xtensive.Orm/IoC/ServiceRegistration.cs
index 230b08031..a227241dd 100644
--- a/Orm/Xtensive.Orm/IoC/ServiceRegistration.cs
+++ b/Orm/Xtensive.Orm/IoC/ServiceRegistration.cs
@@ -4,9 +4,7 @@
 // Created by: Dmitri Maximov
 // Created:    2009.10.12
 
-using System;
 using System.Collections.Concurrent;
-using System.Collections.Generic;
 using Xtensive.Core;
 using Xtensive.Reflection;
 using ServiceRegistrationKey = System.ValueTuple<System.Type, bool>;
diff --git a/Orm/Xtensive.Orm/Linq/ConstantExtractor.cs b/Orm/Xtensive.Orm/Linq/ConstantExtractor.cs
index 732d97268..b829c514b 100644
--- a/Orm/Xtensive.Orm/Linq/ConstantExtractor.cs
+++ b/Orm/Xtensive.Orm/Linq/ConstantExtractor.cs
@@ -4,9 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.05.06
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Linq.Expressions;
 using Xtensive.Collections;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Linq/ExpressionExtensions.cs b/Orm/Xtensive.Orm/Linq/ExpressionExtensions.cs
index 1b8c31d5e..b07fae267 100644
--- a/Orm/Xtensive.Orm/Linq/ExpressionExtensions.cs
+++ b/Orm/Xtensive.Orm/Linq/ExpressionExtensions.cs
@@ -4,9 +4,7 @@
 // Created by: Alexis Kochetov
 // Created:    2009.04.21
 
-using System;
 using System.Collections.Concurrent;
-using System.Linq;
 using System.Linq.Expressions;
 using System.Reflection;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Linq/ExpressionReplacer.cs b/Orm/Xtensive.Orm/Linq/ExpressionReplacer.cs
index 62fb7723f..24ab8f2f3 100644
--- a/Orm/Xtensive.Orm/Linq/ExpressionReplacer.cs
+++ b/Orm/Xtensive.Orm/Linq/ExpressionReplacer.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.03.17
 
-using System.Collections.Generic;
 using System.Linq.Expressions;
 
 namespace Xtensive.Linq
diff --git a/Orm/Xtensive.Orm/Linq/ExpressionTree.cs b/Orm/Xtensive.Orm/Linq/ExpressionTree.cs
index 5b8e03464..5183f3557 100644
--- a/Orm/Xtensive.Orm/Linq/ExpressionTree.cs
+++ b/Orm/Xtensive.Orm/Linq/ExpressionTree.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.05.06
 
-using System;
 using System.Diagnostics;
 using System.Linq.Expressions;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Linq/ExpressionVisitor.cs b/Orm/Xtensive.Orm/Linq/ExpressionVisitor.cs
index 3ec665726..dd074acbc 100644
--- a/Orm/Xtensive.Orm/Linq/ExpressionVisitor.cs
+++ b/Orm/Xtensive.Orm/Linq/ExpressionVisitor.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Kochetov
 // Created:    2008.11.11
 
-using System;
-using System.Collections.Generic;
 using System.Collections.ObjectModel;
 using System.Linq.Expressions;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Linq/ExpressionVisitor{TResult}.cs b/Orm/Xtensive.Orm/Linq/ExpressionVisitor{TResult}.cs
index b9900b549..eb24a9161 100644
--- a/Orm/Xtensive.Orm/Linq/ExpressionVisitor{TResult}.cs
+++ b/Orm/Xtensive.Orm/Linq/ExpressionVisitor{TResult}.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Kochetov
 // Created:    2008.09.05
 
-using System;
-using System.Collections.Generic;
 using System.Collections.ObjectModel;
 using System.Linq.Expressions;
 using Xtensive.Reflection;
diff --git a/Orm/Xtensive.Orm/Linq/ExpressionWriter.cs b/Orm/Xtensive.Orm/Linq/ExpressionWriter.cs
index 7b42ebc7f..59e4939cd 100644
--- a/Orm/Xtensive.Orm/Linq/ExpressionWriter.cs
+++ b/Orm/Xtensive.Orm/Linq/ExpressionWriter.cs
@@ -4,11 +4,9 @@
 // Created by: Alexey Kochetov
 // Created:    2008.11.25
 
-using System;
 using System.Collections;
 using System.Diagnostics;
 using System.IO;
-using System.Linq;
 using System.Linq.Expressions;
 using System.Runtime.CompilerServices;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Linq/FastExpression.cs b/Orm/Xtensive.Orm/Linq/FastExpression.cs
index 624c71f04..bc2be51e4 100644
--- a/Orm/Xtensive.Orm/Linq/FastExpression.cs
+++ b/Orm/Xtensive.Orm/Linq/FastExpression.cs
@@ -4,9 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.05.08
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Linq.Expressions;
 
 namespace Xtensive.Linq
diff --git a/Orm/Xtensive.Orm/Linq/Internals/CachingExpressionCompiler.cs b/Orm/Xtensive.Orm/Linq/Internals/CachingExpressionCompiler.cs
index 6458a33ec..7787c37d2 100644
--- a/Orm/Xtensive.Orm/Linq/Internals/CachingExpressionCompiler.cs
+++ b/Orm/Xtensive.Orm/Linq/Internals/CachingExpressionCompiler.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.05.06
 
-using System;
 using System.Collections.Concurrent;
 using System.Linq.Expressions;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Linq/Internals/ExpressionComparer.cs b/Orm/Xtensive.Orm/Linq/Internals/ExpressionComparer.cs
index b5a4aaea0..24464a764 100644
--- a/Orm/Xtensive.Orm/Linq/Internals/ExpressionComparer.cs
+++ b/Orm/Xtensive.Orm/Linq/Internals/ExpressionComparer.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.05.06
 
-using System;
-using System.Linq;
 using System.Linq.Expressions;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Linq/Internals/ExpressionHashCodeCalculator.cs b/Orm/Xtensive.Orm/Linq/Internals/ExpressionHashCodeCalculator.cs
index e1386eae5..be2d266ff 100644
--- a/Orm/Xtensive.Orm/Linq/Internals/ExpressionHashCodeCalculator.cs
+++ b/Orm/Xtensive.Orm/Linq/Internals/ExpressionHashCodeCalculator.cs
@@ -4,10 +4,7 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.05.06
 
-using System;
 using System.Collections.Concurrent;
-using System.Collections.Generic;
-using System.Linq;
 using System.Linq.Expressions;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Linq/Internals/LambdaExpressionFactory.cs b/Orm/Xtensive.Orm/Linq/Internals/LambdaExpressionFactory.cs
index 2892871f2..db206d847 100644
--- a/Orm/Xtensive.Orm/Linq/Internals/LambdaExpressionFactory.cs
+++ b/Orm/Xtensive.Orm/Linq/Internals/LambdaExpressionFactory.cs
@@ -4,10 +4,7 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.05.07
 
-using System;
-using System.Collections.Generic;
 using System.Collections.Concurrent;
-using System.Linq;
 using System.Linq.Expressions;
 using System.Reflection;
 using Xtensive.Reflection;
diff --git a/Orm/Xtensive.Orm/Linq/Internals/ParameterExpressionRegistry.cs b/Orm/Xtensive.Orm/Linq/Internals/ParameterExpressionRegistry.cs
index 01cce3d0c..dd5c88ad2 100644
--- a/Orm/Xtensive.Orm/Linq/Internals/ParameterExpressionRegistry.cs
+++ b/Orm/Xtensive.Orm/Linq/Internals/ParameterExpressionRegistry.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.05.06
 
-using System.Collections.Generic;
 using System.Linq.Expressions;
 
 namespace Xtensive.Linq
diff --git a/Orm/Xtensive.Orm/Linq/QueryableMethodKind.cs b/Orm/Xtensive.Orm/Linq/QueryableMethodKind.cs
index b1d0fd458..5d56c7e89 100644
--- a/Orm/Xtensive.Orm/Linq/QueryableMethodKind.cs
+++ b/Orm/Xtensive.Orm/Linq/QueryableMethodKind.cs
@@ -4,8 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.02.25
 
-using System;
-using System.Linq;
 
 namespace Xtensive.Linq
 {
diff --git a/Orm/Xtensive.Orm/Linq/QueryableVisitor.cs b/Orm/Xtensive.Orm/Linq/QueryableVisitor.cs
index 726077af1..26a6cd34e 100644
--- a/Orm/Xtensive.Orm/Linq/QueryableVisitor.cs
+++ b/Orm/Xtensive.Orm/Linq/QueryableVisitor.cs
@@ -4,9 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.02.25
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Linq.Expressions;
 using Xtensive.Reflection;
 
diff --git a/Orm/Xtensive.Orm/Linq/SerializableExpressions/Internals/ExpressionToSerializableExpressionConverter.cs b/Orm/Xtensive.Orm/Linq/SerializableExpressions/Internals/ExpressionToSerializableExpressionConverter.cs
index df87b52d0..acba862e1 100644
--- a/Orm/Xtensive.Orm/Linq/SerializableExpressions/Internals/ExpressionToSerializableExpressionConverter.cs
+++ b/Orm/Xtensive.Orm/Linq/SerializableExpressions/Internals/ExpressionToSerializableExpressionConverter.cs
@@ -4,9 +4,6 @@
 // Created by: Denis Kryuchkov
 // Created:    2009.05.13
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Linq.Expressions;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Linq/SerializableExpressions/Internals/ReflectionExtensions.cs b/Orm/Xtensive.Orm/Linq/SerializableExpressions/Internals/ReflectionExtensions.cs
index e10da7298..e0db1dc5c 100644
--- a/Orm/Xtensive.Orm/Linq/SerializableExpressions/Internals/ReflectionExtensions.cs
+++ b/Orm/Xtensive.Orm/Linq/SerializableExpressions/Internals/ReflectionExtensions.cs
@@ -4,8 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2010.02.25
 
-using System;
-using System.Linq;
 using System.Reflection;
 using System.Runtime.Serialization;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Linq/SerializableExpressions/Internals/SerializableExpressionToExpressionConverter.cs b/Orm/Xtensive.Orm/Linq/SerializableExpressions/Internals/SerializableExpressionToExpressionConverter.cs
index 06c5ce318..3a0747231 100644
--- a/Orm/Xtensive.Orm/Linq/SerializableExpressions/Internals/SerializableExpressionToExpressionConverter.cs
+++ b/Orm/Xtensive.Orm/Linq/SerializableExpressions/Internals/SerializableExpressionToExpressionConverter.cs
@@ -4,9 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.05.13
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Linq.Expressions;
 using System.Reflection;
 
diff --git a/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableBinaryExpression.cs b/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableBinaryExpression.cs
index cf68689ed..95190d4e1 100644
--- a/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableBinaryExpression.cs
+++ b/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableBinaryExpression.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.05.12
 
-using System;
 using System.Linq.Expressions;
 using System.Reflection;
 using System.Runtime.Serialization;
diff --git a/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableConditionalExpression.cs b/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableConditionalExpression.cs
index 8b2d94309..0b36be52e 100644
--- a/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableConditionalExpression.cs
+++ b/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableConditionalExpression.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.05.12
 
-using System;
 using System.Linq.Expressions;
 using System.Runtime.Serialization;
 using System.Security;
diff --git a/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableConstantExpression.cs b/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableConstantExpression.cs
index 1f4135929..33d153f13 100644
--- a/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableConstantExpression.cs
+++ b/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableConstantExpression.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.05.12
 
-using System;
 using System.Linq.Expressions;
 using System.Runtime.Serialization;
 using System.Security;
diff --git a/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableDefaultExpression.cs b/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableDefaultExpression.cs
index eae7cd156..7e6f4b51b 100644
--- a/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableDefaultExpression.cs
+++ b/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableDefaultExpression.cs
@@ -2,7 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
 using System.Linq.Expressions;
 using System.Runtime.Serialization;
 
diff --git a/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableElementInit.cs b/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableElementInit.cs
index dab5d0f28..82e8f604c 100644
--- a/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableElementInit.cs
+++ b/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableElementInit.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Kryuchkov
 // Created:    2009.05.14
 
-using System;
 using System.Linq.Expressions;
 using System.Reflection;
 using System.Runtime.Serialization;
diff --git a/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableExpression.cs b/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableExpression.cs
index 07338c6a3..3d360dfeb 100644
--- a/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableExpression.cs
+++ b/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableExpression.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.05.12
 
-using System;
 using System.Linq.Expressions;
 using System.Runtime.Serialization;
 using System.Security;
diff --git a/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableInvocationExpression.cs b/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableInvocationExpression.cs
index 34f485bf6..eafe4fb79 100644
--- a/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableInvocationExpression.cs
+++ b/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableInvocationExpression.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.05.13
 
-using System;
 using System.Linq.Expressions;
 using System.Runtime.Serialization;
 using System.Security;
diff --git a/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableLambdaExpression.cs b/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableLambdaExpression.cs
index badfb89c1..23f678d0f 100644
--- a/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableLambdaExpression.cs
+++ b/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableLambdaExpression.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.05.12
 
-using System;
 using System.Linq.Expressions;
 using System.Runtime.Serialization;
 using System.Security;
diff --git a/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableListInitExpression.cs b/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableListInitExpression.cs
index c0a36828d..17f1a8fa6 100644
--- a/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableListInitExpression.cs
+++ b/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableListInitExpression.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.05.13
 
-using System;
 using System.Linq.Expressions;
 using System.Runtime.Serialization;
 using System.Security;
diff --git a/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableMemberAssignment.cs b/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableMemberAssignment.cs
index 43a098252..8c5aee89e 100644
--- a/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableMemberAssignment.cs
+++ b/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableMemberAssignment.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.05.15
 
-using System;
 using System.Linq.Expressions;
 using System.Runtime.Serialization;
 using System.Security;
diff --git a/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableMemberBinding.cs b/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableMemberBinding.cs
index 0011a2f7a..b77be1f32 100644
--- a/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableMemberBinding.cs
+++ b/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableMemberBinding.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.05.15
 
-using System;
 using System.Linq.Expressions;
 using System.Reflection;
 using System.Runtime.Serialization;
diff --git a/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableMemberExpression.cs b/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableMemberExpression.cs
index 685f07be5..12caae3c3 100644
--- a/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableMemberExpression.cs
+++ b/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableMemberExpression.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.05.12
 
-using System;
-using System.Collections.Generic;
 using System.Linq.Expressions;
 using System.Reflection;
 using System.Runtime.Serialization;
diff --git a/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableMemberInitExpression.cs b/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableMemberInitExpression.cs
index 682d6420d..03895b0df 100644
--- a/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableMemberInitExpression.cs
+++ b/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableMemberInitExpression.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.05.13
 
-using System;
 using System.Linq.Expressions;
 using System.Runtime.Serialization;
 using System.Security;
diff --git a/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableMemberListBinding.cs b/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableMemberListBinding.cs
index d6c146555..731c9c7ab 100644
--- a/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableMemberListBinding.cs
+++ b/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableMemberListBinding.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Kryuchkov
 // Created:    2009.05.15
 
-using System;
 using System.Linq.Expressions;
 using System.Runtime.Serialization;
 using System.Security;
diff --git a/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableMemberMemberBinding.cs b/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableMemberMemberBinding.cs
index edbd19808..602105c8e 100644
--- a/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableMemberMemberBinding.cs
+++ b/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableMemberMemberBinding.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.05.15
 
-using System;
 using System.Linq.Expressions;
 using System.Runtime.Serialization;
 using System.Security;
diff --git a/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableMethodCallExpression.cs b/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableMethodCallExpression.cs
index e5002b074..945d91bf3 100644
--- a/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableMethodCallExpression.cs
+++ b/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableMethodCallExpression.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.05.12
 
-using System;
 using System.Linq.Expressions;
 using System.Reflection;
 using System.Runtime.Serialization;
diff --git a/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableNewArrayExpression.cs b/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableNewArrayExpression.cs
index 2930e7ec1..e88cd39f7 100644
--- a/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableNewArrayExpression.cs
+++ b/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableNewArrayExpression.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.05.13
 
-using System;
 using System.Linq.Expressions;
 using System.Runtime.Serialization;
 using System.Security;
diff --git a/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableNewExpression.cs b/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableNewExpression.cs
index 98ba732f5..0a15f1ea6 100644
--- a/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableNewExpression.cs
+++ b/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableNewExpression.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.05.12
 
-using System;
-using System.Linq;
 using System.Linq.Expressions;
 using System.Reflection;
 using System.Runtime.Serialization;
diff --git a/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableParameterExpression.cs b/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableParameterExpression.cs
index 69d2d40df..ae1d531d5 100644
--- a/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableParameterExpression.cs
+++ b/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableParameterExpression.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.05.12
 
-using System;
 using System.Linq.Expressions;
 using System.Runtime.Serialization;
 using System.Security;
diff --git a/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableTypeBinaryExpression.cs b/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableTypeBinaryExpression.cs
index 2ae414725..ad54661f3 100644
--- a/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableTypeBinaryExpression.cs
+++ b/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableTypeBinaryExpression.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.05.12
 
-using System;
 using System.Linq.Expressions;
 using System.Runtime.Serialization;
 using System.Security;
diff --git a/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableUnaryExpression.cs b/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableUnaryExpression.cs
index 73b403fd9..f4f204dc2 100644
--- a/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableUnaryExpression.cs
+++ b/Orm/Xtensive.Orm/Linq/SerializableExpressions/SerializableUnaryExpression.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.05.12
 
-using System;
 using System.Linq.Expressions;
 using System.Reflection;
 using System.Runtime.Serialization;
diff --git a/Orm/Xtensive.Orm/Modelling/Actions/ActionHandler.cs b/Orm/Xtensive.Orm/Modelling/Actions/ActionHandler.cs
index 5c6e38ef1..29e0f1523 100644
--- a/Orm/Xtensive.Orm/Modelling/Actions/ActionHandler.cs
+++ b/Orm/Xtensive.Orm/Modelling/Actions/ActionHandler.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2009.04.20
 
-using System;
 using Xtensive.Core;
 using Xtensive.IoC;
 
diff --git a/Orm/Xtensive.Orm/Modelling/Actions/ActionScope.cs b/Orm/Xtensive.Orm/Modelling/Actions/ActionScope.cs
index 6ec24389b..c29270160 100644
--- a/Orm/Xtensive.Orm/Modelling/Actions/ActionScope.cs
+++ b/Orm/Xtensive.Orm/Modelling/Actions/ActionScope.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2009.03.23
 
-using System;
 using System.Diagnostics;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Modelling/Actions/ActionSequence.cs b/Orm/Xtensive.Orm/Modelling/Actions/ActionSequence.cs
index 3fc6a7084..e03b47796 100644
--- a/Orm/Xtensive.Orm/Modelling/Actions/ActionSequence.cs
+++ b/Orm/Xtensive.Orm/Modelling/Actions/ActionSequence.cs
@@ -4,9 +4,7 @@
 // Created by: Alex Yakunin
 // Created:    2009.03.23
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
 using System.Text;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Modelling/Actions/CreateNodeAction.cs b/Orm/Xtensive.Orm/Modelling/Actions/CreateNodeAction.cs
index 33ed0ae2c..67dc16b82 100644
--- a/Orm/Xtensive.Orm/Modelling/Actions/CreateNodeAction.cs
+++ b/Orm/Xtensive.Orm/Modelling/Actions/CreateNodeAction.cs
@@ -4,13 +4,10 @@
 // Created by: Alex Yakunin
 // Created:    2009.03.23
 
-using System;
-using System.Collections.Generic;
 using Xtensive.Core;
 using Xtensive.Reflection;
 using Xtensive.Collections;
 
-using System.Linq;
 
 namespace Xtensive.Modelling.Actions
 {
diff --git a/Orm/Xtensive.Orm/Modelling/Actions/DataAction.cs b/Orm/Xtensive.Orm/Modelling/Actions/DataAction.cs
index e3e50cdcb..98c39609d 100644
--- a/Orm/Xtensive.Orm/Modelling/Actions/DataAction.cs
+++ b/Orm/Xtensive.Orm/Modelling/Actions/DataAction.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.05.14
 
-using System;
 using Xtensive.Core;
 using Xtensive.Modelling.Comparison.Hints;
 
diff --git a/Orm/Xtensive.Orm/Modelling/Actions/GroupingNodeAction.cs b/Orm/Xtensive.Orm/Modelling/Actions/GroupingNodeAction.cs
index a9143563f..94d8b7325 100644
--- a/Orm/Xtensive.Orm/Modelling/Actions/GroupingNodeAction.cs
+++ b/Orm/Xtensive.Orm/Modelling/Actions/GroupingNodeAction.cs
@@ -4,10 +4,7 @@
 // Created by: Alex Yakunin
 // Created:    2009.04.22
 
-using System;
-using System.Collections.Generic;
 using System.Collections.ObjectModel;
-using System.Linq;
 using Xtensive.Core;
 
 namespace Xtensive.Modelling.Actions
diff --git a/Orm/Xtensive.Orm/Modelling/Actions/Interfaces/IActionSequence.cs b/Orm/Xtensive.Orm/Modelling/Actions/Interfaces/IActionSequence.cs
index 9574f151e..f85db393e 100644
--- a/Orm/Xtensive.Orm/Modelling/Actions/Interfaces/IActionSequence.cs
+++ b/Orm/Xtensive.Orm/Modelling/Actions/Interfaces/IActionSequence.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2009.03.23
 
-using System.Collections.Generic;
 using Xtensive.Core;
 
 namespace Xtensive.Modelling.Actions
diff --git a/Orm/Xtensive.Orm/Modelling/Actions/MoveNodeAction.cs b/Orm/Xtensive.Orm/Modelling/Actions/MoveNodeAction.cs
index 709f71764..9ceb14e40 100644
--- a/Orm/Xtensive.Orm/Modelling/Actions/MoveNodeAction.cs
+++ b/Orm/Xtensive.Orm/Modelling/Actions/MoveNodeAction.cs
@@ -4,13 +4,10 @@
 // Created by: Alex Yakunin
 // Created:    2009.03.23
 
-using System;
-using System.Collections.Generic;
 using Xtensive.Core;
 using Xtensive.Reflection;
 using Xtensive.Collections;
 
-using System.Linq;
 
 namespace Xtensive.Modelling.Actions
 {
diff --git a/Orm/Xtensive.Orm/Modelling/Actions/NodeAction.cs b/Orm/Xtensive.Orm/Modelling/Actions/NodeAction.cs
index a3d79ae76..b3eba320c 100644
--- a/Orm/Xtensive.Orm/Modelling/Actions/NodeAction.cs
+++ b/Orm/Xtensive.Orm/Modelling/Actions/NodeAction.cs
@@ -4,15 +4,12 @@
 // Created by: Alex Yakunin
 // Created:    2009.03.23
 
-using System;
-using System.Collections.Generic;
 using System.Text;
 using Xtensive.Collections;
 using Xtensive.Core;
 
 using Xtensive.Reflection;
 using Xtensive.Modelling.Comparison;
-using System.Linq;
 
 namespace Xtensive.Modelling.Actions
 {
diff --git a/Orm/Xtensive.Orm/Modelling/Actions/NullActionHandler.cs b/Orm/Xtensive.Orm/Modelling/Actions/NullActionHandler.cs
index 9c77e14a0..cf12962e1 100644
--- a/Orm/Xtensive.Orm/Modelling/Actions/NullActionHandler.cs
+++ b/Orm/Xtensive.Orm/Modelling/Actions/NullActionHandler.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2009.04.20
 
-using System;
 
 namespace Xtensive.Modelling.Actions
 {
diff --git a/Orm/Xtensive.Orm/Modelling/Actions/PathNodeReference.cs b/Orm/Xtensive.Orm/Modelling/Actions/PathNodeReference.cs
index d91fb30ba..27a415fdb 100644
--- a/Orm/Xtensive.Orm/Modelling/Actions/PathNodeReference.cs
+++ b/Orm/Xtensive.Orm/Modelling/Actions/PathNodeReference.cs
@@ -2,7 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
 
 
 namespace Xtensive.Modelling.Actions
diff --git a/Orm/Xtensive.Orm/Modelling/Actions/PropertyChangeAction.cs b/Orm/Xtensive.Orm/Modelling/Actions/PropertyChangeAction.cs
index b9acdb975..ef9385493 100644
--- a/Orm/Xtensive.Orm/Modelling/Actions/PropertyChangeAction.cs
+++ b/Orm/Xtensive.Orm/Modelling/Actions/PropertyChangeAction.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2009.03.23
 
-using System;
-using System.Collections.Generic;
 using System.Collections.ObjectModel;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Modelling/Actions/RemoveNodeAction.cs b/Orm/Xtensive.Orm/Modelling/Actions/RemoveNodeAction.cs
index 74efa2352..556fc29bb 100644
--- a/Orm/Xtensive.Orm/Modelling/Actions/RemoveNodeAction.cs
+++ b/Orm/Xtensive.Orm/Modelling/Actions/RemoveNodeAction.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2009.03.23
 
-using System;
 using System.Diagnostics;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Modelling/Attributes/DataDependentAttribute.cs b/Orm/Xtensive.Orm/Modelling/Attributes/DataDependentAttribute.cs
index 24ba4ba49..e7c244819 100644
--- a/Orm/Xtensive.Orm/Modelling/Attributes/DataDependentAttribute.cs
+++ b/Orm/Xtensive.Orm/Modelling/Attributes/DataDependentAttribute.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2009.03.18
 
-using System;
 
 namespace Xtensive.Modelling.Attributes
 {
diff --git a/Orm/Xtensive.Orm/Modelling/Attributes/PropertyAttribute.cs b/Orm/Xtensive.Orm/Modelling/Attributes/PropertyAttribute.cs
index d6982fe8a..3c604d98f 100644
--- a/Orm/Xtensive.Orm/Modelling/Attributes/PropertyAttribute.cs
+++ b/Orm/Xtensive.Orm/Modelling/Attributes/PropertyAttribute.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2009.03.18
 
-using System;
 
 namespace Xtensive.Modelling.Attributes
 {
diff --git a/Orm/Xtensive.Orm/Modelling/Attributes/SystemPropertyAttribute.cs b/Orm/Xtensive.Orm/Modelling/Attributes/SystemPropertyAttribute.cs
index 794299de7..ebd7cda61 100644
--- a/Orm/Xtensive.Orm/Modelling/Attributes/SystemPropertyAttribute.cs
+++ b/Orm/Xtensive.Orm/Modelling/Attributes/SystemPropertyAttribute.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2009.03.18
 
-using System;
 using System.Diagnostics;
 
 
diff --git a/Orm/Xtensive.Orm/Modelling/CloningContext.cs b/Orm/Xtensive.Orm/Modelling/CloningContext.cs
index cb8aef7db..c452300d4 100644
--- a/Orm/Xtensive.Orm/Modelling/CloningContext.cs
+++ b/Orm/Xtensive.Orm/Modelling/CloningContext.cs
@@ -4,9 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2009.03.23
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Collections;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Modelling/Comparison/Comparer.cs b/Orm/Xtensive.Orm/Modelling/Comparison/Comparer.cs
index b32e8da39..80d550f70 100644
--- a/Orm/Xtensive.Orm/Modelling/Comparison/Comparer.cs
+++ b/Orm/Xtensive.Orm/Modelling/Comparison/Comparer.cs
@@ -4,11 +4,7 @@
 // Created by: Alex Yakunin
 // Created:    2009.04.07
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
-using System.Linq;
-using System.Threading;
 using Xtensive.Collections;
 using Xtensive.Core;
 using Xtensive.Reflection;
diff --git a/Orm/Xtensive.Orm/Modelling/Comparison/ComparisonContext.cs b/Orm/Xtensive.Orm/Modelling/Comparison/ComparisonContext.cs
index 7bca36c34..d22555156 100644
--- a/Orm/Xtensive.Orm/Modelling/Comparison/ComparisonContext.cs
+++ b/Orm/Xtensive.Orm/Modelling/Comparison/ComparisonContext.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2009.04.16
 
-using System;
 using Xtensive.Core;
 
 
diff --git a/Orm/Xtensive.Orm/Modelling/Comparison/Difference.cs b/Orm/Xtensive.Orm/Modelling/Comparison/Difference.cs
index c0f420e99..87a096e52 100644
--- a/Orm/Xtensive.Orm/Modelling/Comparison/Difference.cs
+++ b/Orm/Xtensive.Orm/Modelling/Comparison/Difference.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2009.03.25
 
-using System;
-using System.Collections.Generic;
 using System.Diagnostics;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Modelling/Comparison/Hints/CopyDataHint.cs b/Orm/Xtensive.Orm/Modelling/Comparison/Hints/CopyDataHint.cs
index d171ce4eb..e58a8eea3 100644
--- a/Orm/Xtensive.Orm/Modelling/Comparison/Hints/CopyDataHint.cs
+++ b/Orm/Xtensive.Orm/Modelling/Comparison/Hints/CopyDataHint.cs
@@ -4,10 +4,7 @@
 // Created by: Ivan Galkin
 // Created:    2009.05.30
 
-using System;
-using System.Collections.Generic;
 using System.Collections.ObjectModel;
-using System.Linq;
 using Xtensive.Core;
 
 
diff --git a/Orm/Xtensive.Orm/Modelling/Comparison/Hints/DataHint.cs b/Orm/Xtensive.Orm/Modelling/Comparison/Hints/DataHint.cs
index 59cb05663..40d931b3f 100644
--- a/Orm/Xtensive.Orm/Modelling/Comparison/Hints/DataHint.cs
+++ b/Orm/Xtensive.Orm/Modelling/Comparison/Hints/DataHint.cs
@@ -4,8 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.06.01
 
-using System;
-using System.Collections.Generic;
 using System.Collections.ObjectModel;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Modelling/Comparison/Hints/DeleteDataHint.cs b/Orm/Xtensive.Orm/Modelling/Comparison/Hints/DeleteDataHint.cs
index 1afc129a2..52de31728 100644
--- a/Orm/Xtensive.Orm/Modelling/Comparison/Hints/DeleteDataHint.cs
+++ b/Orm/Xtensive.Orm/Modelling/Comparison/Hints/DeleteDataHint.cs
@@ -4,9 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.05.30
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 
 
 namespace Xtensive.Modelling.Comparison.Hints
diff --git a/Orm/Xtensive.Orm/Modelling/Comparison/Hints/Hint.cs b/Orm/Xtensive.Orm/Modelling/Comparison/Hints/Hint.cs
index 6cbf03730..8af9ae272 100644
--- a/Orm/Xtensive.Orm/Modelling/Comparison/Hints/Hint.cs
+++ b/Orm/Xtensive.Orm/Modelling/Comparison/Hints/Hint.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2009.03.26
 
-using System;
-using System.Collections.Generic;
 
 namespace Xtensive.Modelling.Comparison.Hints
 {
diff --git a/Orm/Xtensive.Orm/Modelling/Comparison/Hints/HintSet.cs b/Orm/Xtensive.Orm/Modelling/Comparison/Hints/HintSet.cs
index ca57611be..782c5c064 100644
--- a/Orm/Xtensive.Orm/Modelling/Comparison/Hints/HintSet.cs
+++ b/Orm/Xtensive.Orm/Modelling/Comparison/Hints/HintSet.cs
@@ -4,13 +4,10 @@
 // Created by: Alex Yakunin
 // Created:    2009.03.26
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
 using System.Diagnostics;
 using System.Reflection;
 using Xtensive.Collections;
-using System.Linq;
 using Xtensive.Core;
 
 namespace Xtensive.Modelling.Comparison.Hints
diff --git a/Orm/Xtensive.Orm/Modelling/Comparison/Hints/HintTarget.cs b/Orm/Xtensive.Orm/Modelling/Comparison/Hints/HintTarget.cs
index 210cb4d28..0811c9205 100644
--- a/Orm/Xtensive.Orm/Modelling/Comparison/Hints/HintTarget.cs
+++ b/Orm/Xtensive.Orm/Modelling/Comparison/Hints/HintTarget.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2009.03.26
 
-using System;
 
 
 namespace Xtensive.Modelling.Comparison.Hints
diff --git a/Orm/Xtensive.Orm/Modelling/Comparison/Hints/IdentityPair.cs b/Orm/Xtensive.Orm/Modelling/Comparison/Hints/IdentityPair.cs
index 32e39e89c..f65eeeffe 100644
--- a/Orm/Xtensive.Orm/Modelling/Comparison/Hints/IdentityPair.cs
+++ b/Orm/Xtensive.Orm/Modelling/Comparison/Hints/IdentityPair.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.06.02
 
-using System;
 using System.Diagnostics;
 
 
diff --git a/Orm/Xtensive.Orm/Modelling/Comparison/Hints/IgnoreHint.cs b/Orm/Xtensive.Orm/Modelling/Comparison/Hints/IgnoreHint.cs
index 6b079cfb9..86400fc7c 100644
--- a/Orm/Xtensive.Orm/Modelling/Comparison/Hints/IgnoreHint.cs
+++ b/Orm/Xtensive.Orm/Modelling/Comparison/Hints/IgnoreHint.cs
@@ -4,10 +4,7 @@
 // Created by: Ivan Galkin
 // Created:    2009.05.28
 
-using System;
-using System.Collections.Generic;
 using System.Diagnostics;
-using System.Linq;
 using Xtensive.Core;
 
 
diff --git a/Orm/Xtensive.Orm/Modelling/Comparison/Hints/Interfaces/IHint.cs b/Orm/Xtensive.Orm/Modelling/Comparison/Hints/Interfaces/IHint.cs
index 11ef90ebc..8cdd7d75c 100644
--- a/Orm/Xtensive.Orm/Modelling/Comparison/Hints/Interfaces/IHint.cs
+++ b/Orm/Xtensive.Orm/Modelling/Comparison/Hints/Interfaces/IHint.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2009.03.26
 
-using System.Collections.Generic;
 
 namespace Xtensive.Modelling.Comparison.Hints
 {
diff --git a/Orm/Xtensive.Orm/Modelling/Comparison/Hints/Interfaces/IHintSet.cs b/Orm/Xtensive.Orm/Modelling/Comparison/Hints/Interfaces/IHintSet.cs
index d8d3a4e9d..7e39f7907 100644
--- a/Orm/Xtensive.Orm/Modelling/Comparison/Hints/Interfaces/IHintSet.cs
+++ b/Orm/Xtensive.Orm/Modelling/Comparison/Hints/Interfaces/IHintSet.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2009.03.26
 
-using System.Collections.Generic;
 using Xtensive.Core;
 using Xtensive.Collections;
 
diff --git a/Orm/Xtensive.Orm/Modelling/Comparison/Hints/RenameHint.cs b/Orm/Xtensive.Orm/Modelling/Comparison/Hints/RenameHint.cs
index 5de36f2b1..260b9bfbf 100644
--- a/Orm/Xtensive.Orm/Modelling/Comparison/Hints/RenameHint.cs
+++ b/Orm/Xtensive.Orm/Modelling/Comparison/Hints/RenameHint.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2009.03.28
 
-using System;
-using System.Collections.Generic;
 using System.Diagnostics;
 
 
diff --git a/Orm/Xtensive.Orm/Modelling/Comparison/Hints/UpdateDataHint.cs b/Orm/Xtensive.Orm/Modelling/Comparison/Hints/UpdateDataHint.cs
index 344a949cb..a9ec9e5e0 100644
--- a/Orm/Xtensive.Orm/Modelling/Comparison/Hints/UpdateDataHint.cs
+++ b/Orm/Xtensive.Orm/Modelling/Comparison/Hints/UpdateDataHint.cs
@@ -4,10 +4,7 @@
 // Created by: Ivan Galkin
 // Created:    2009.05.30
 
-using System;
-using System.Collections.Generic;
 using System.Collections.ObjectModel;
-using System.Linq;
 using Xtensive.Core;
 
 
diff --git a/Orm/Xtensive.Orm/Modelling/Comparison/Interfaces/IDifference.cs b/Orm/Xtensive.Orm/Modelling/Comparison/Interfaces/IDifference.cs
index 509b173ad..f962ed2fd 100644
--- a/Orm/Xtensive.Orm/Modelling/Comparison/Interfaces/IDifference.cs
+++ b/Orm/Xtensive.Orm/Modelling/Comparison/Interfaces/IDifference.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2009.03.25
 
-using System.Collections.Generic;
 using Xtensive.Modelling.Actions;
 
 namespace Xtensive.Modelling.Comparison
diff --git a/Orm/Xtensive.Orm/Modelling/Comparison/Interfaces/IHasPropertyChanges.cs b/Orm/Xtensive.Orm/Modelling/Comparison/Interfaces/IHasPropertyChanges.cs
index 00cb710f3..4f32df713 100644
--- a/Orm/Xtensive.Orm/Modelling/Comparison/Interfaces/IHasPropertyChanges.cs
+++ b/Orm/Xtensive.Orm/Modelling/Comparison/Interfaces/IHasPropertyChanges.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2009.04.15
 
-using System.Collections.Generic;
 
 namespace Xtensive.Modelling.Comparison
 {
diff --git a/Orm/Xtensive.Orm/Modelling/Comparison/Interfaces/IUpgrader.cs b/Orm/Xtensive.Orm/Modelling/Comparison/Interfaces/IUpgrader.cs
index 19b6aaa75..458f4c06a 100644
--- a/Orm/Xtensive.Orm/Modelling/Comparison/Interfaces/IUpgrader.cs
+++ b/Orm/Xtensive.Orm/Modelling/Comparison/Interfaces/IUpgrader.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2009.04.20
 
-using System.Collections.Generic;
 using Xtensive.Modelling.Actions;
 using Xtensive.Modelling.Comparison.Hints;
 
diff --git a/Orm/Xtensive.Orm/Modelling/Comparison/MovementInfo.cs b/Orm/Xtensive.Orm/Modelling/Comparison/MovementInfo.cs
index 58b0cdbaf..b867e0197 100644
--- a/Orm/Xtensive.Orm/Modelling/Comparison/MovementInfo.cs
+++ b/Orm/Xtensive.Orm/Modelling/Comparison/MovementInfo.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2009.03.25
 
-using System;
 using System.Text;
 
 
diff --git a/Orm/Xtensive.Orm/Modelling/Comparison/NodeCollectionDifference.cs b/Orm/Xtensive.Orm/Modelling/Comparison/NodeCollectionDifference.cs
index cde27ee9c..1084a0ad6 100644
--- a/Orm/Xtensive.Orm/Modelling/Comparison/NodeCollectionDifference.cs
+++ b/Orm/Xtensive.Orm/Modelling/Comparison/NodeCollectionDifference.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2009.03.25
 
-using System;
-using System.Collections.Generic;
 using System.Diagnostics;
 using System.Text;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Modelling/Comparison/NodeDifference.cs b/Orm/Xtensive.Orm/Modelling/Comparison/NodeDifference.cs
index a47f8fe55..f8cf7881e 100644
--- a/Orm/Xtensive.Orm/Modelling/Comparison/NodeDifference.cs
+++ b/Orm/Xtensive.Orm/Modelling/Comparison/NodeDifference.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2009.03.25
 
-using System;
-using System.Collections.Generic;
 using System.Text;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Modelling/Comparison/UpgradeContext.cs b/Orm/Xtensive.Orm/Modelling/Comparison/UpgradeContext.cs
index bc3657a13..025890aea 100644
--- a/Orm/Xtensive.Orm/Modelling/Comparison/UpgradeContext.cs
+++ b/Orm/Xtensive.Orm/Modelling/Comparison/UpgradeContext.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2009.04.16
 
-using System;
 using Xtensive.Core;
 
 using Xtensive.Modelling.Actions;
diff --git a/Orm/Xtensive.Orm/Modelling/Comparison/Upgrader.cs b/Orm/Xtensive.Orm/Modelling/Comparison/Upgrader.cs
index ac08660c5..941aa9c45 100644
--- a/Orm/Xtensive.Orm/Modelling/Comparison/Upgrader.cs
+++ b/Orm/Xtensive.Orm/Modelling/Comparison/Upgrader.cs
@@ -4,11 +4,7 @@
 // Created by: Alex Yakunin
 // Created:    2009.04.07
 
-using System;
-using System.Collections.Generic;
 using System.Collections.ObjectModel;
-using System.Linq;
-using System.Threading;
 using Xtensive.Collections;
 using Xtensive.Core;
 using Xtensive.Modelling.Actions;
diff --git a/Orm/Xtensive.Orm/Modelling/Comparison/ValueDifference.cs b/Orm/Xtensive.Orm/Modelling/Comparison/ValueDifference.cs
index 0051af00d..2f5141fce 100644
--- a/Orm/Xtensive.Orm/Modelling/Comparison/ValueDifference.cs
+++ b/Orm/Xtensive.Orm/Modelling/Comparison/ValueDifference.cs
@@ -4,9 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2009.03.28
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Core;
 using Xtensive.Modelling.Actions;
 
diff --git a/Orm/Xtensive.Orm/Modelling/Interfaces/IModel.cs b/Orm/Xtensive.Orm/Modelling/Interfaces/IModel.cs
index fa4144401..941dd02b7 100644
--- a/Orm/Xtensive.Orm/Modelling/Interfaces/IModel.cs
+++ b/Orm/Xtensive.Orm/Modelling/Interfaces/IModel.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2009.03.20
 
-using System;
-using System.Collections.Generic;
 using Xtensive.Modelling.Actions;
 
 namespace Xtensive.Modelling
diff --git a/Orm/Xtensive.Orm/Modelling/Interfaces/INesting.cs b/Orm/Xtensive.Orm/Modelling/Interfaces/INesting.cs
index 31622fedd..975e201f8 100644
--- a/Orm/Xtensive.Orm/Modelling/Interfaces/INesting.cs
+++ b/Orm/Xtensive.Orm/Modelling/Interfaces/INesting.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2009.03.18
 
-using System;
 using System.Reflection;
 
 namespace Xtensive.Modelling
diff --git a/Orm/Xtensive.Orm/Modelling/Interfaces/INode.cs b/Orm/Xtensive.Orm/Modelling/Interfaces/INode.cs
index 5e3eb2aa4..751e00781 100644
--- a/Orm/Xtensive.Orm/Modelling/Interfaces/INode.cs
+++ b/Orm/Xtensive.Orm/Modelling/Interfaces/INode.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2009.03.17
 
-using System.Collections.Generic;
 using System.ComponentModel;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Modelling/Interfaces/INodeCollection{TNode}.cs b/Orm/Xtensive.Orm/Modelling/Interfaces/INodeCollection{TNode}.cs
index 6b449a68b..513059f8b 100644
--- a/Orm/Xtensive.Orm/Modelling/Interfaces/INodeCollection{TNode}.cs
+++ b/Orm/Xtensive.Orm/Modelling/Interfaces/INodeCollection{TNode}.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2009.03.18
 
-using System.Collections.Generic;
 using Xtensive.Collections;
 
 namespace Xtensive.Modelling
diff --git a/Orm/Xtensive.Orm/Modelling/Interfaces/IUnorderedNodeCollection.cs b/Orm/Xtensive.Orm/Modelling/Interfaces/IUnorderedNodeCollection.cs
index 56c21a5d0..a7725e6a6 100644
--- a/Orm/Xtensive.Orm/Modelling/Interfaces/IUnorderedNodeCollection.cs
+++ b/Orm/Xtensive.Orm/Modelling/Interfaces/IUnorderedNodeCollection.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2009.03.20
 
-using System;
 using System.Diagnostics;
 
 namespace Xtensive.Modelling
diff --git a/Orm/Xtensive.Orm/Modelling/Nesting.cs b/Orm/Xtensive.Orm/Modelling/Nesting.cs
index 2f786f948..48ba68d95 100644
--- a/Orm/Xtensive.Orm/Modelling/Nesting.cs
+++ b/Orm/Xtensive.Orm/Modelling/Nesting.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2009.03.18
 
-using System;
 using System.Diagnostics;
 using System.Reflection;
 using System.Runtime.Serialization;
diff --git a/Orm/Xtensive.Orm/Modelling/Nesting{TNode, TParent, TProperty}.cs b/Orm/Xtensive.Orm/Modelling/Nesting{TNode, TParent, TProperty}.cs
index f5aa7687d..ca2615ff6 100644
--- a/Orm/Xtensive.Orm/Modelling/Nesting{TNode, TParent, TProperty}.cs	
+++ b/Orm/Xtensive.Orm/Modelling/Nesting{TNode, TParent, TProperty}.cs	
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2009.03.18
 
-using System;
 using System.Diagnostics;
 using System.Reflection;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Modelling/Node.cs b/Orm/Xtensive.Orm/Modelling/Node.cs
index 824d6d28f..cc8bf14d9 100644
--- a/Orm/Xtensive.Orm/Modelling/Node.cs
+++ b/Orm/Xtensive.Orm/Modelling/Node.cs
@@ -4,9 +4,7 @@
 // Created by: Alex Yakunin
 // Created:    2009.03.16
 
-using System;
 using System.Collections.Concurrent;
-using System.Collections.Generic;
 using System.ComponentModel;
 using System.Diagnostics;
 using System.Reflection;
@@ -17,7 +15,6 @@
 
 using Xtensive.Reflection;
 using Xtensive.Modelling.Validation;
-using System.Linq;
 
 namespace Xtensive.Modelling
 {
diff --git a/Orm/Xtensive.Orm/Modelling/NodeCollection.cs b/Orm/Xtensive.Orm/Modelling/NodeCollection.cs
index 68b106b75..425a1f7f7 100644
--- a/Orm/Xtensive.Orm/Modelling/NodeCollection.cs
+++ b/Orm/Xtensive.Orm/Modelling/NodeCollection.cs
@@ -4,9 +4,7 @@
 // Created by: Alex Yakunin
 // Created:    2009.03.16
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
 using System.Collections.Specialized;
 using System.Diagnostics;
 using System.Runtime.Serialization;
diff --git a/Orm/Xtensive.Orm/Modelling/NodeCollection{TNode, TParent, TModel}.cs b/Orm/Xtensive.Orm/Modelling/NodeCollection{TNode, TParent, TModel}.cs
index 23e93bb9a..f677ff68f 100644
--- a/Orm/Xtensive.Orm/Modelling/NodeCollection{TNode, TParent, TModel}.cs	
+++ b/Orm/Xtensive.Orm/Modelling/NodeCollection{TNode, TParent, TModel}.cs	
@@ -4,9 +4,7 @@
 // Created by: Alex Yakunin
 // Created:    2009.03.20
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
 using System.Diagnostics;
 
 namespace Xtensive.Modelling
diff --git a/Orm/Xtensive.Orm/Modelling/Node{TParent, TModel}.cs b/Orm/Xtensive.Orm/Modelling/Node{TParent, TModel}.cs
index e81bdc3b5..728f5951e 100644
--- a/Orm/Xtensive.Orm/Modelling/Node{TParent, TModel}.cs	
+++ b/Orm/Xtensive.Orm/Modelling/Node{TParent, TModel}.cs	
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2009.03.16
 
-using System;
 using System.Diagnostics;
 
 
diff --git a/Orm/Xtensive.Orm/Modelling/PathNodeExtensions.cs b/Orm/Xtensive.Orm/Modelling/PathNodeExtensions.cs
index f44479c85..8e66e3cfe 100644
--- a/Orm/Xtensive.Orm/Modelling/PathNodeExtensions.cs
+++ b/Orm/Xtensive.Orm/Modelling/PathNodeExtensions.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2010.07.05
 
-using System;
 using System.Diagnostics;
 
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Modelling/PropertyAccessor.cs b/Orm/Xtensive.Orm/Modelling/PropertyAccessor.cs
index 909ebf348..6a178443d 100644
--- a/Orm/Xtensive.Orm/Modelling/PropertyAccessor.cs
+++ b/Orm/Xtensive.Orm/Modelling/PropertyAccessor.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2009.03.18
 
-using System;
 using System.Reflection;
 using Xtensive.Collections;
 
diff --git a/Orm/Xtensive.Orm/Modelling/PropertyAccessorDictionary.cs b/Orm/Xtensive.Orm/Modelling/PropertyAccessorDictionary.cs
index 8e0d64639..a9bc4114b 100644
--- a/Orm/Xtensive.Orm/Modelling/PropertyAccessorDictionary.cs
+++ b/Orm/Xtensive.Orm/Modelling/PropertyAccessorDictionary.cs
@@ -4,11 +4,8 @@
 // Created by: Alex Yakunin
 // Created:    2009.04.01
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
 using System.Diagnostics.CodeAnalysis;
-using System.Linq;
 
 namespace Xtensive.Modelling
 {
diff --git a/Orm/Xtensive.Orm/Modelling/Validation/ValidationContext.cs b/Orm/Xtensive.Orm/Modelling/Validation/ValidationContext.cs
index 2f51f66df..803b2064d 100644
--- a/Orm/Xtensive.Orm/Modelling/Validation/ValidationContext.cs
+++ b/Orm/Xtensive.Orm/Modelling/Validation/ValidationContext.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2009.03.23
 
-using System;
-using System.Collections.Generic;
 using Xtensive.Core;
 
 using Xtensive.IoC;
diff --git a/Orm/Xtensive.Orm/Orm/Attributes/AssociationAttribute.cs b/Orm/Xtensive.Orm/Orm/Attributes/AssociationAttribute.cs
index 2332e4da4..281c7446d 100644
--- a/Orm/Xtensive.Orm/Orm/Attributes/AssociationAttribute.cs
+++ b/Orm/Xtensive.Orm/Orm/Attributes/AssociationAttribute.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2009.06.07
 
-using System;
 
 
 namespace Xtensive.Orm
diff --git a/Orm/Xtensive.Orm/Orm/Attributes/CompilerAttribute.cs b/Orm/Xtensive.Orm/Orm/Attributes/CompilerAttribute.cs
index 28eee111f..ce24a58f4 100644
--- a/Orm/Xtensive.Orm/Orm/Attributes/CompilerAttribute.cs
+++ b/Orm/Xtensive.Orm/Orm/Attributes/CompilerAttribute.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.02.09
 
-using System;
 using JetBrains.Annotations;
 
 
diff --git a/Orm/Xtensive.Orm/Orm/Attributes/CompilerContainerAttribute.cs b/Orm/Xtensive.Orm/Orm/Attributes/CompilerContainerAttribute.cs
index 9430593fd..e25bc4db7 100644
--- a/Orm/Xtensive.Orm/Orm/Attributes/CompilerContainerAttribute.cs
+++ b/Orm/Xtensive.Orm/Orm/Attributes/CompilerContainerAttribute.cs
@@ -4,7 +4,6 @@
 // Created by: Elena Vakhtina
 // Created:    2009.03.30
 
-using System;
 using JetBrains.Annotations;
 
 
diff --git a/Orm/Xtensive.Orm/Orm/Attributes/FieldAttribute.cs b/Orm/Xtensive.Orm/Orm/Attributes/FieldAttribute.cs
index e6ec16bfb..a8def39cc 100644
--- a/Orm/Xtensive.Orm/Orm/Attributes/FieldAttribute.cs
+++ b/Orm/Xtensive.Orm/Orm/Attributes/FieldAttribute.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2007.07.04
 
-using System;
 
 namespace Xtensive.Orm
 {
diff --git a/Orm/Xtensive.Orm/Orm/Attributes/FieldMappingAttribute.cs b/Orm/Xtensive.Orm/Orm/Attributes/FieldMappingAttribute.cs
index 28e0ed91f..5322b85f1 100644
--- a/Orm/Xtensive.Orm/Orm/Attributes/FieldMappingAttribute.cs
+++ b/Orm/Xtensive.Orm/Orm/Attributes/FieldMappingAttribute.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2009.07.10
 
-using System;
 
 
 namespace Xtensive.Orm
diff --git a/Orm/Xtensive.Orm/Orm/Attributes/FullTextAttribute.cs b/Orm/Xtensive.Orm/Orm/Attributes/FullTextAttribute.cs
index c348cdaa3..51e3ddf3c 100644
--- a/Orm/Xtensive.Orm/Orm/Attributes/FullTextAttribute.cs
+++ b/Orm/Xtensive.Orm/Orm/Attributes/FullTextAttribute.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.12.14
 
-using System;
 
 
 namespace Xtensive.Orm
diff --git a/Orm/Xtensive.Orm/Orm/Attributes/HierarchyRootAttribute.cs b/Orm/Xtensive.Orm/Orm/Attributes/HierarchyRootAttribute.cs
index 0499da40f..d5408b37d 100644
--- a/Orm/Xtensive.Orm/Orm/Attributes/HierarchyRootAttribute.cs
+++ b/Orm/Xtensive.Orm/Orm/Attributes/HierarchyRootAttribute.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2008.01.11
 
-using System;
 using JetBrains.Annotations;
 using Xtensive.Orm.Model;
 
diff --git a/Orm/Xtensive.Orm/Orm/Attributes/IndexAttribute.cs b/Orm/Xtensive.Orm/Orm/Attributes/IndexAttribute.cs
index cc60ba07e..742356327 100644
--- a/Orm/Xtensive.Orm/Orm/Attributes/IndexAttribute.cs
+++ b/Orm/Xtensive.Orm/Orm/Attributes/IndexAttribute.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using System.Linq.Expressions;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Orm/Attributes/KeyAttribute.cs b/Orm/Xtensive.Orm/Orm/Attributes/KeyAttribute.cs
index 75373077e..796ed317b 100644
--- a/Orm/Xtensive.Orm/Orm/Attributes/KeyAttribute.cs
+++ b/Orm/Xtensive.Orm/Orm/Attributes/KeyAttribute.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2009.05.26
 
-using System;
 using Xtensive.Core;
 
 
diff --git a/Orm/Xtensive.Orm/Orm/Attributes/KeyGeneratorAttribute.cs b/Orm/Xtensive.Orm/Orm/Attributes/KeyGeneratorAttribute.cs
index 92adb8eda..c8b437ded 100644
--- a/Orm/Xtensive.Orm/Orm/Attributes/KeyGeneratorAttribute.cs
+++ b/Orm/Xtensive.Orm/Orm/Attributes/KeyGeneratorAttribute.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2009.05.26
 
-using System;
 using Xtensive.Core;
 
 using Xtensive.Reflection;
diff --git a/Orm/Xtensive.Orm/Orm/Attributes/MaterializedViewAttribute.cs b/Orm/Xtensive.Orm/Orm/Attributes/MaterializedViewAttribute.cs
index 2ca7dd548..611a33d62 100644
--- a/Orm/Xtensive.Orm/Orm/Attributes/MaterializedViewAttribute.cs
+++ b/Orm/Xtensive.Orm/Orm/Attributes/MaterializedViewAttribute.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kochetov
 // Created:    2007.12.28
 
-using System;
 
 namespace Xtensive.Orm
 {
diff --git a/Orm/Xtensive.Orm/Orm/Attributes/StorageAttribute.cs b/Orm/Xtensive.Orm/Orm/Attributes/StorageAttribute.cs
index 168b58654..94296e61b 100644
--- a/Orm/Xtensive.Orm/Orm/Attributes/StorageAttribute.cs
+++ b/Orm/Xtensive.Orm/Orm/Attributes/StorageAttribute.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2008.01.11
 
-using System;
 
 namespace Xtensive.Orm
 {
diff --git a/Orm/Xtensive.Orm/Orm/Attributes/SystemTypeAttribute.cs b/Orm/Xtensive.Orm/Orm/Attributes/SystemTypeAttribute.cs
index 327300f48..7a8e2965b 100644
--- a/Orm/Xtensive.Orm/Orm/Attributes/SystemTypeAttribute.cs
+++ b/Orm/Xtensive.Orm/Orm/Attributes/SystemTypeAttribute.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Kofman
 // Created:    2008.12.24
 
-using System;
 
 using Xtensive.Orm.Model;
 
diff --git a/Orm/Xtensive.Orm/Orm/Attributes/TableMappingAttribute.cs b/Orm/Xtensive.Orm/Orm/Attributes/TableMappingAttribute.cs
index d977b6773..65a6032bb 100644
--- a/Orm/Xtensive.Orm/Orm/Attributes/TableMappingAttribute.cs
+++ b/Orm/Xtensive.Orm/Orm/Attributes/TableMappingAttribute.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2007.07.04
 
-using System;
 
 
 namespace Xtensive.Orm
diff --git a/Orm/Xtensive.Orm/Orm/Attributes/TypeAttribute.cs b/Orm/Xtensive.Orm/Orm/Attributes/TypeAttribute.cs
index b382a6109..a4afe1160 100644
--- a/Orm/Xtensive.Orm/Orm/Attributes/TypeAttribute.cs
+++ b/Orm/Xtensive.Orm/Orm/Attributes/TypeAttribute.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.02.09
 
-using System;
 
 
 namespace Xtensive.Orm
diff --git a/Orm/Xtensive.Orm/Orm/Attributes/TypeDiscriminatorAttribute.cs b/Orm/Xtensive.Orm/Orm/Attributes/TypeDiscriminatorAttribute.cs
index 2b37aabed..beeabca59 100644
--- a/Orm/Xtensive.Orm/Orm/Attributes/TypeDiscriminatorAttribute.cs
+++ b/Orm/Xtensive.Orm/Orm/Attributes/TypeDiscriminatorAttribute.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.08.13
 
-using System;
 
 
 namespace Xtensive.Orm
diff --git a/Orm/Xtensive.Orm/Orm/Attributes/TypeDiscriminatorValueAttribute.cs b/Orm/Xtensive.Orm/Orm/Attributes/TypeDiscriminatorValueAttribute.cs
index 1bcbee06e..6fcd8b690 100644
--- a/Orm/Xtensive.Orm/Orm/Attributes/TypeDiscriminatorValueAttribute.cs
+++ b/Orm/Xtensive.Orm/Orm/Attributes/TypeDiscriminatorValueAttribute.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2009.11.25
 
-using System;
 
 
 namespace Xtensive.Orm
diff --git a/Orm/Xtensive.Orm/Orm/Attributes/VersionAttribute.cs b/Orm/Xtensive.Orm/Orm/Attributes/VersionAttribute.cs
index 4e1dea0db..4a24f0ef3 100644
--- a/Orm/Xtensive.Orm/Orm/Attributes/VersionAttribute.cs
+++ b/Orm/Xtensive.Orm/Orm/Attributes/VersionAttribute.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.08.13
 
-using System;
 
 
 namespace Xtensive.Orm
diff --git a/Orm/Xtensive.Orm/Orm/Attributes/VersionMode.cs b/Orm/Xtensive.Orm/Orm/Attributes/VersionMode.cs
index edaa0c8fc..2643fa148 100644
--- a/Orm/Xtensive.Orm/Orm/Attributes/VersionMode.cs
+++ b/Orm/Xtensive.Orm/Orm/Attributes/VersionMode.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2010.08.04
 
-using System;
 
 namespace Xtensive.Orm
 {
diff --git a/Orm/Xtensive.Orm/Orm/Building/Builders/AssociationBuilder.cs b/Orm/Xtensive.Orm/Orm/Building/Builders/AssociationBuilder.cs
index db882628e..a2b972c52 100644
--- a/Orm/Xtensive.Orm/Orm/Building/Builders/AssociationBuilder.cs
+++ b/Orm/Xtensive.Orm/Orm/Building/Builders/AssociationBuilder.cs
@@ -4,8 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2008.07.03
 
-using System;
-using System.Linq;
 using Xtensive.Core;
 using Xtensive.Reflection;
 using Xtensive.Orm.Building.Definitions;
diff --git a/Orm/Xtensive.Orm/Orm/Building/Builders/AttributeProcessor.cs b/Orm/Xtensive.Orm/Orm/Building/Builders/AttributeProcessor.cs
index 645331f05..379e838ab 100644
--- a/Orm/Xtensive.Orm/Orm/Building/Builders/AttributeProcessor.cs
+++ b/Orm/Xtensive.Orm/Orm/Building/Builders/AttributeProcessor.cs
@@ -4,8 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2007.09.25
 
-using System;
-using System.Collections.Generic;
 using System.Linq.Expressions;
 using System.Reflection;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Orm/Building/Builders/AutoGenericCombinator.cs b/Orm/Xtensive.Orm/Orm/Building/Builders/AutoGenericCombinator.cs
index 85e69ee92..136c572c9 100644
--- a/Orm/Xtensive.Orm/Orm/Building/Builders/AutoGenericCombinator.cs
+++ b/Orm/Xtensive.Orm/Orm/Building/Builders/AutoGenericCombinator.cs
@@ -1,5 +1,3 @@
-using System;
-using System.Collections.Generic;
 
 namespace Xtensive.Orm.Building.Builders
 {
diff --git a/Orm/Xtensive.Orm/Orm/Building/Builders/DatabaseDependencyBuilder.cs b/Orm/Xtensive.Orm/Orm/Building/Builders/DatabaseDependencyBuilder.cs
index 010e3cf27..b6220d708 100644
--- a/Orm/Xtensive.Orm/Orm/Building/Builders/DatabaseDependencyBuilder.cs
+++ b/Orm/Xtensive.Orm/Orm/Building/Builders/DatabaseDependencyBuilder.cs
@@ -4,9 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.03.22
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Core;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Model;
diff --git a/Orm/Xtensive.Orm/Orm/Building/Builders/DomainBuilder.cs b/Orm/Xtensive.Orm/Orm/Building/Builders/DomainBuilder.cs
index 74cd2ddbb..4d56eddf7 100644
--- a/Orm/Xtensive.Orm/Orm/Building/Builders/DomainBuilder.cs
+++ b/Orm/Xtensive.Orm/Orm/Building/Builders/DomainBuilder.cs
@@ -4,8 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2007.08.03
 
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Core;
 using Xtensive.IoC;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm/Orm/Building/Builders/DomainBuilderConfiguration.cs b/Orm/Xtensive.Orm/Orm/Building/Builders/DomainBuilderConfiguration.cs
index 129ec03d9..c91835cee 100644
--- a/Orm/Xtensive.Orm/Orm/Building/Builders/DomainBuilderConfiguration.cs
+++ b/Orm/Xtensive.Orm/Orm/Building/Builders/DomainBuilderConfiguration.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2009.05.01
 
-using System.Collections.Generic;
 using System.Collections.ObjectModel;
 using Xtensive.Core;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm/Orm/Building/Builders/IModelFilter.cs b/Orm/Xtensive.Orm/Orm/Building/Builders/IModelFilter.cs
index 735a3622e..00bdc5762 100644
--- a/Orm/Xtensive.Orm/Orm/Building/Builders/IModelFilter.cs
+++ b/Orm/Xtensive.Orm/Orm/Building/Builders/IModelFilter.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.03.14
 
-using System;
 using System.Reflection;
 
 namespace Xtensive.Orm.Building.Builders
diff --git a/Orm/Xtensive.Orm/Orm/Building/Builders/ITypeIdProvider.cs b/Orm/Xtensive.Orm/Orm/Building/Builders/ITypeIdProvider.cs
index f136a978c..2e6e7f8f4 100644
--- a/Orm/Xtensive.Orm/Orm/Building/Builders/ITypeIdProvider.cs
+++ b/Orm/Xtensive.Orm/Orm/Building/Builders/ITypeIdProvider.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.03.19
 
-using System;
 
 namespace Xtensive.Orm.Building.Builders
 {
diff --git a/Orm/Xtensive.Orm/Orm/Building/Builders/IndexBuilder.ClassTable.cs b/Orm/Xtensive.Orm/Orm/Building/Builders/IndexBuilder.ClassTable.cs
index b88dde496..7cf30b01f 100644
--- a/Orm/Xtensive.Orm/Orm/Building/Builders/IndexBuilder.ClassTable.cs
+++ b/Orm/Xtensive.Orm/Orm/Building/Builders/IndexBuilder.ClassTable.cs
@@ -4,9 +4,6 @@
 // Created by: Alexander Nikolaev
 // Created:    2009.06.17
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Core;
 using Xtensive.Orm.Model;
 
diff --git a/Orm/Xtensive.Orm/Orm/Building/Builders/IndexBuilder.ClusteredIndexes.cs b/Orm/Xtensive.Orm/Orm/Building/Builders/IndexBuilder.ClusteredIndexes.cs
index 7e4590c27..ff001f72e 100644
--- a/Orm/Xtensive.Orm/Orm/Building/Builders/IndexBuilder.ClusteredIndexes.cs
+++ b/Orm/Xtensive.Orm/Orm/Building/Builders/IndexBuilder.ClusteredIndexes.cs
@@ -4,9 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2011.10.25
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Core;
 using Xtensive.Orm.Model;
 
diff --git a/Orm/Xtensive.Orm/Orm/Building/Builders/IndexBuilder.ConcreteTable.cs b/Orm/Xtensive.Orm/Orm/Building/Builders/IndexBuilder.ConcreteTable.cs
index 47442faec..e23dd9829 100644
--- a/Orm/Xtensive.Orm/Orm/Building/Builders/IndexBuilder.ConcreteTable.cs
+++ b/Orm/Xtensive.Orm/Orm/Building/Builders/IndexBuilder.ConcreteTable.cs
@@ -4,8 +4,6 @@
 // Created by: Alexander Nikolaev
 // Created:    2009.06.17
 
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Core;
 using Xtensive.Orm.Model;
 
diff --git a/Orm/Xtensive.Orm/Orm/Building/Builders/IndexBuilder.FullText.cs b/Orm/Xtensive.Orm/Orm/Building/Builders/IndexBuilder.FullText.cs
index 6c5486821..617882ad0 100644
--- a/Orm/Xtensive.Orm/Orm/Building/Builders/IndexBuilder.FullText.cs
+++ b/Orm/Xtensive.Orm/Orm/Building/Builders/IndexBuilder.FullText.cs
@@ -4,9 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.12.16
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Core;
 using Xtensive.Orm.Building.Definitions;
 using Xtensive.Orm.Model;
diff --git a/Orm/Xtensive.Orm/Orm/Building/Builders/IndexBuilder.SingleTable.cs b/Orm/Xtensive.Orm/Orm/Building/Builders/IndexBuilder.SingleTable.cs
index 13f6f2500..bc7fb5904 100644
--- a/Orm/Xtensive.Orm/Orm/Building/Builders/IndexBuilder.SingleTable.cs
+++ b/Orm/Xtensive.Orm/Orm/Building/Builders/IndexBuilder.SingleTable.cs
@@ -4,9 +4,6 @@
 // Created by: Alexander Nikolaev
 // Created:    2009.06.17
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Core;
 using Xtensive.Orm.Model;
 
diff --git a/Orm/Xtensive.Orm/Orm/Building/Builders/IndexBuilder.cs b/Orm/Xtensive.Orm/Orm/Building/Builders/IndexBuilder.cs
index 67d82ab66..7e3fab99d 100644
--- a/Orm/Xtensive.Orm/Orm/Building/Builders/IndexBuilder.cs
+++ b/Orm/Xtensive.Orm/Orm/Building/Builders/IndexBuilder.cs
@@ -4,9 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2007.10.02
 
-using System;
-using System.Linq;
-using System.Collections.Generic;
 using Xtensive.Collections;
 using Xtensive.Core;
 using Xtensive.Orm.Building.Definitions;
diff --git a/Orm/Xtensive.Orm/Orm/Building/Builders/KeyGeneratorFactory.cs b/Orm/Xtensive.Orm/Orm/Building/Builders/KeyGeneratorFactory.cs
index c89790813..be76723dd 100644
--- a/Orm/Xtensive.Orm/Orm/Building/Builders/KeyGeneratorFactory.cs
+++ b/Orm/Xtensive.Orm/Orm/Building/Builders/KeyGeneratorFactory.cs
@@ -4,9 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.03.08
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.IoC;
 using Xtensive.Orm.Internals.KeyGenerators;
 using Xtensive.Reflection;
diff --git a/Orm/Xtensive.Orm/Orm/Building/Builders/MemberCompilerProviderBuilder.cs b/Orm/Xtensive.Orm/Orm/Building/Builders/MemberCompilerProviderBuilder.cs
index 910dddd04..c5a4a8715 100644
--- a/Orm/Xtensive.Orm/Orm/Building/Builders/MemberCompilerProviderBuilder.cs
+++ b/Orm/Xtensive.Orm/Orm/Building/Builders/MemberCompilerProviderBuilder.cs
@@ -4,9 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2011.10.27
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Linq.Expressions;
 using System.Reflection;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Orm/Building/Builders/ModelBuilder.cs b/Orm/Xtensive.Orm/Orm/Building/Builders/ModelBuilder.cs
index 3c6050ea4..da4b76af3 100644
--- a/Orm/Xtensive.Orm/Orm/Building/Builders/ModelBuilder.cs
+++ b/Orm/Xtensive.Orm/Orm/Building/Builders/ModelBuilder.cs
@@ -4,10 +4,7 @@
 // Created by: Dmitri Maximov
 // Created:    2007.09.26
 
-using System;
 using System.Collections.Concurrent;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Core;
 using Xtensive.Orm.Building.Definitions;
 using Xtensive.Orm.Building.DependencyGraph;
diff --git a/Orm/Xtensive.Orm/Orm/Building/Builders/ModelDefBuilder.cs b/Orm/Xtensive.Orm/Orm/Building/Builders/ModelDefBuilder.cs
index b89640ad4..3d9e0d998 100644
--- a/Orm/Xtensive.Orm/Orm/Building/Builders/ModelDefBuilder.cs
+++ b/Orm/Xtensive.Orm/Orm/Building/Builders/ModelDefBuilder.cs
@@ -4,9 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2009.05.20
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Reflection;
 using Xtensive.Collections;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Orm/Building/Builders/ModelMappingBuilder.cs b/Orm/Xtensive.Orm/Orm/Building/Builders/ModelMappingBuilder.cs
index cbd2ada86..d3e12150f 100644
--- a/Orm/Xtensive.Orm/Orm/Building/Builders/ModelMappingBuilder.cs
+++ b/Orm/Xtensive.Orm/Orm/Building/Builders/ModelMappingBuilder.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.03.06
 
-using System;
-using System.Linq;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Model;
 using Xtensive.Orm.Providers;
diff --git a/Orm/Xtensive.Orm/Orm/Building/Builders/PartialIndexFilterBuilder.cs b/Orm/Xtensive.Orm/Orm/Building/Builders/PartialIndexFilterBuilder.cs
index f8ecf94d2..e02adf561 100644
--- a/Orm/Xtensive.Orm/Orm/Building/Builders/PartialIndexFilterBuilder.cs
+++ b/Orm/Xtensive.Orm/Orm/Building/Builders/PartialIndexFilterBuilder.cs
@@ -4,9 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2011.10.07
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Linq.Expressions;
 using System.Reflection;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Orm/Building/Builders/ProviderDescriptor.cs b/Orm/Xtensive.Orm/Orm/Building/Builders/ProviderDescriptor.cs
index 01d59339a..81cbc21c2 100644
--- a/Orm/Xtensive.Orm/Orm/Building/Builders/ProviderDescriptor.cs
+++ b/Orm/Xtensive.Orm/Orm/Building/Builders/ProviderDescriptor.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.03.01
 
-using System;
-using System.Linq;
 using System.Reflection;
 using Xtensive.Core;
 using Xtensive.Orm.Providers;
diff --git a/Orm/Xtensive.Orm/Orm/Building/Builders/StorageMappingBuilder.cs b/Orm/Xtensive.Orm/Orm/Building/Builders/StorageMappingBuilder.cs
index 9ad2d578e..e7d74ec55 100644
--- a/Orm/Xtensive.Orm/Orm/Building/Builders/StorageMappingBuilder.cs
+++ b/Orm/Xtensive.Orm/Orm/Building/Builders/StorageMappingBuilder.cs
@@ -4,9 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.02.10
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Reflection;
 using Xtensive.Orm.Logging;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm/Orm/Building/Builders/StorageMappingValidator.cs b/Orm/Xtensive.Orm/Orm/Building/Builders/StorageMappingValidator.cs
index 57e79afdf..dad0b235c 100644
--- a/Orm/Xtensive.Orm/Orm/Building/Builders/StorageMappingValidator.cs
+++ b/Orm/Xtensive.Orm/Orm/Building/Builders/StorageMappingValidator.cs
@@ -4,9 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.02.13
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Core;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Model;
diff --git a/Orm/Xtensive.Orm/Orm/Building/Builders/TypeBuilder.cs b/Orm/Xtensive.Orm/Orm/Building/Builders/TypeBuilder.cs
index 0db467dc8..506c80df2 100644
--- a/Orm/Xtensive.Orm/Orm/Building/Builders/TypeBuilder.cs
+++ b/Orm/Xtensive.Orm/Orm/Building/Builders/TypeBuilder.cs
@@ -4,9 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2007.10.02
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Reflection;
 using Xtensive.Core;
 using Xtensive.Orm.Building.Definitions;
diff --git a/Orm/Xtensive.Orm/Orm/Building/Builders/TypeIdBuilder.cs b/Orm/Xtensive.Orm/Orm/Building/Builders/TypeIdBuilder.cs
index 032815ebe..bcb664efc 100644
--- a/Orm/Xtensive.Orm/Orm/Building/Builders/TypeIdBuilder.cs
+++ b/Orm/Xtensive.Orm/Orm/Building/Builders/TypeIdBuilder.cs
@@ -4,9 +4,6 @@
 // Created by: Alex Kofman
 // Created:    2009.04.14
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Core;
 using Xtensive.Orm.Model;
 
diff --git a/Orm/Xtensive.Orm/Orm/Building/Builders/ValueTypeBuilder.cs b/Orm/Xtensive.Orm/Orm/Building/Builders/ValueTypeBuilder.cs
index b2775bf24..31c6103ab 100644
--- a/Orm/Xtensive.Orm/Orm/Building/Builders/ValueTypeBuilder.cs
+++ b/Orm/Xtensive.Orm/Orm/Building/Builders/ValueTypeBuilder.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2011.09.27
 
-using System;
 using Xtensive.Reflection;
 using Xtensive.Orm.Building.Definitions;
 using Xtensive.Orm.Internals;
diff --git a/Orm/Xtensive.Orm/Orm/Building/BuildingContext.cs b/Orm/Xtensive.Orm/Orm/Building/BuildingContext.cs
index e911e81c5..9564ccc3a 100644
--- a/Orm/Xtensive.Orm/Orm/Building/BuildingContext.cs
+++ b/Orm/Xtensive.Orm/Orm/Building/BuildingContext.cs
@@ -4,9 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2007.09.03
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Core;
 using Xtensive.Orm.Building.Builders;
 using Xtensive.Orm.Building.Definitions;
diff --git a/Orm/Xtensive.Orm/Orm/Building/Definitions/DomainModelDef.cs b/Orm/Xtensive.Orm/Orm/Building/Definitions/DomainModelDef.cs
index f3c20abc1..91629d13c 100644
--- a/Orm/Xtensive.Orm/Orm/Building/Definitions/DomainModelDef.cs
+++ b/Orm/Xtensive.Orm/Orm/Building/Definitions/DomainModelDef.cs
@@ -4,15 +4,12 @@
 // Created by: Alex Ustinov
 // Created:    2007.07.11
 
-using System;
-using System.Collections.Generic;
 using Xtensive.Collections;
 using Xtensive.Core;
 using Xtensive.Reflection;
 using Xtensive.Orm.Building.Builders;
 using Xtensive.Orm.Model;
 
-using System.Linq;
 
 namespace Xtensive.Orm.Building.Definitions
 {
diff --git a/Orm/Xtensive.Orm/Orm/Building/Definitions/FieldDef.cs b/Orm/Xtensive.Orm/Orm/Building/Definitions/FieldDef.cs
index 3fb5d381f..e9272e58e 100644
--- a/Orm/Xtensive.Orm/Orm/Building/Definitions/FieldDef.cs
+++ b/Orm/Xtensive.Orm/Orm/Building/Definitions/FieldDef.cs
@@ -4,8 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2007.09.10
 
-using System;
-using System.Collections.Generic;
 using System.Diagnostics;
 using System.Reflection;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Orm/Building/Definitions/FullTextFieldDef.cs b/Orm/Xtensive.Orm/Orm/Building/Definitions/FullTextFieldDef.cs
index 6addafb99..1d196e3f7 100644
--- a/Orm/Xtensive.Orm/Orm/Building/Definitions/FullTextFieldDef.cs
+++ b/Orm/Xtensive.Orm/Orm/Building/Definitions/FullTextFieldDef.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2010.01.18
 
-using System;
 using System.Diagnostics;
 
 using Xtensive.Orm.Model;
diff --git a/Orm/Xtensive.Orm/Orm/Building/Definitions/FullTextIndexDef.cs b/Orm/Xtensive.Orm/Orm/Building/Definitions/FullTextIndexDef.cs
index b00088b15..aee216791 100644
--- a/Orm/Xtensive.Orm/Orm/Building/Definitions/FullTextIndexDef.cs
+++ b/Orm/Xtensive.Orm/Orm/Building/Definitions/FullTextIndexDef.cs
@@ -4,8 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.12.21
 
-using System;
-using System.Collections.Generic;
 using System.Diagnostics;
 
 using Xtensive.Orm.Model;
diff --git a/Orm/Xtensive.Orm/Orm/Building/Definitions/FullTextIndexDefCollection.cs b/Orm/Xtensive.Orm/Orm/Building/Definitions/FullTextIndexDefCollection.cs
index 83039a496..5cbc27185 100644
--- a/Orm/Xtensive.Orm/Orm/Building/Definitions/FullTextIndexDefCollection.cs
+++ b/Orm/Xtensive.Orm/Orm/Building/Definitions/FullTextIndexDefCollection.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.12.21
 
-using System;
 using System.Diagnostics;
 using Xtensive.Collections;
 
diff --git a/Orm/Xtensive.Orm/Orm/Building/Definitions/HierarchyDef.cs b/Orm/Xtensive.Orm/Orm/Building/Definitions/HierarchyDef.cs
index fe0ce9dfb..a485c9652 100644
--- a/Orm/Xtensive.Orm/Orm/Building/Definitions/HierarchyDef.cs
+++ b/Orm/Xtensive.Orm/Orm/Building/Definitions/HierarchyDef.cs
@@ -4,8 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2008.01.11
 
-using System;
-using System.Collections.Generic;
 using Xtensive.Core;
 using Xtensive.Orm.Model;
 
diff --git a/Orm/Xtensive.Orm/Orm/Building/Definitions/HierarchyDefCollection.cs b/Orm/Xtensive.Orm/Orm/Building/Definitions/HierarchyDefCollection.cs
index 44393df99..d3e48534e 100644
--- a/Orm/Xtensive.Orm/Orm/Building/Definitions/HierarchyDefCollection.cs
+++ b/Orm/Xtensive.Orm/Orm/Building/Definitions/HierarchyDefCollection.cs
@@ -4,9 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2008.01.11
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Core;
 using Xtensive.Collections;
 
diff --git a/Orm/Xtensive.Orm/Orm/Building/Definitions/IndexDef.cs b/Orm/Xtensive.Orm/Orm/Building/Definitions/IndexDef.cs
index dc4e5656a..24cf2a0ac 100644
--- a/Orm/Xtensive.Orm/Orm/Building/Definitions/IndexDef.cs
+++ b/Orm/Xtensive.Orm/Orm/Building/Definitions/IndexDef.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2007.09.29
 
-using System;
 using System.Collections.ObjectModel;
 using System.Diagnostics;
 using System.Linq.Expressions;
diff --git a/Orm/Xtensive.Orm/Orm/Building/Definitions/TypeDef.cs b/Orm/Xtensive.Orm/Orm/Building/Definitions/TypeDef.cs
index b53e13c8b..0a2a411a3 100644
--- a/Orm/Xtensive.Orm/Orm/Building/Definitions/TypeDef.cs
+++ b/Orm/Xtensive.Orm/Orm/Building/Definitions/TypeDef.cs
@@ -4,8 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2007.08.27
 
-using System;
-using System.Collections.Generic;
 using System.Diagnostics;
 using System.Reflection;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Orm/Building/Definitions/TypeDefCollection.cs b/Orm/Xtensive.Orm/Orm/Building/Definitions/TypeDefCollection.cs
index 4d09822e9..aae41e6e7 100644
--- a/Orm/Xtensive.Orm/Orm/Building/Definitions/TypeDefCollection.cs
+++ b/Orm/Xtensive.Orm/Orm/Building/Definitions/TypeDefCollection.cs
@@ -4,9 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2007.08.27
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Core;
 using Xtensive.Orm.Model;
 using Xtensive.Reflection;
diff --git a/Orm/Xtensive.Orm/Orm/Building/DependencyGraph/Edge.cs b/Orm/Xtensive.Orm/Orm/Building/DependencyGraph/Edge.cs
index 530e76fc4..81e508e9e 100644
--- a/Orm/Xtensive.Orm/Orm/Building/DependencyGraph/Edge.cs
+++ b/Orm/Xtensive.Orm/Orm/Building/DependencyGraph/Edge.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2009.02.24
 
-using System;
 
 namespace Xtensive.Orm.Building.DependencyGraph
 {
diff --git a/Orm/Xtensive.Orm/Orm/Building/DependencyGraph/EdgeKind.cs b/Orm/Xtensive.Orm/Orm/Building/DependencyGraph/EdgeKind.cs
index 7b5797dd5..d4414b2bd 100644
--- a/Orm/Xtensive.Orm/Orm/Building/DependencyGraph/EdgeKind.cs
+++ b/Orm/Xtensive.Orm/Orm/Building/DependencyGraph/EdgeKind.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2009.02.24
 
-using System;
 
 namespace Xtensive.Orm.Building.DependencyGraph
 {
diff --git a/Orm/Xtensive.Orm/Orm/Building/DependencyGraph/EdgeWeight.cs b/Orm/Xtensive.Orm/Orm/Building/DependencyGraph/EdgeWeight.cs
index b0b36f33b..7c64daf57 100644
--- a/Orm/Xtensive.Orm/Orm/Building/DependencyGraph/EdgeWeight.cs
+++ b/Orm/Xtensive.Orm/Orm/Building/DependencyGraph/EdgeWeight.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2009.05.20
 
-using System;
 
 namespace Xtensive.Orm.Building.DependencyGraph
 {
diff --git a/Orm/Xtensive.Orm/Orm/Building/DependencyGraph/Graph.cs b/Orm/Xtensive.Orm/Orm/Building/DependencyGraph/Graph.cs
index 64f366532..0f1a85b8e 100644
--- a/Orm/Xtensive.Orm/Orm/Building/DependencyGraph/Graph.cs
+++ b/Orm/Xtensive.Orm/Orm/Building/DependencyGraph/Graph.cs
@@ -4,8 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2009.09.12
 
-using System;
-using System.Collections.Generic;
 
 namespace Xtensive.Orm.Building.DependencyGraph
 {
diff --git a/Orm/Xtensive.Orm/Orm/Building/DependencyGraph/Node.cs b/Orm/Xtensive.Orm/Orm/Building/DependencyGraph/Node.cs
index dffe663e6..a8cd9d357 100644
--- a/Orm/Xtensive.Orm/Orm/Building/DependencyGraph/Node.cs
+++ b/Orm/Xtensive.Orm/Orm/Building/DependencyGraph/Node.cs
@@ -4,8 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2009.09.12
 
-using System;
-using System.Collections.Generic;
 
 namespace Xtensive.Orm.Building.DependencyGraph
 {
diff --git a/Orm/Xtensive.Orm/Orm/Building/FixupActionProcessor.cs b/Orm/Xtensive.Orm/Orm/Building/FixupActionProcessor.cs
index 9de81fbf6..3fe48f4e8 100644
--- a/Orm/Xtensive.Orm/Orm/Building/FixupActionProcessor.cs
+++ b/Orm/Xtensive.Orm/Orm/Building/FixupActionProcessor.cs
@@ -4,9 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2009.05.28
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Orm.Building.Builders;
 using Xtensive.Orm.Building.Definitions;
 using Xtensive.Orm.Building.DependencyGraph;
diff --git a/Orm/Xtensive.Orm/Orm/Building/FixupActions/MakeTypeNonAbstractAction.cs b/Orm/Xtensive.Orm/Orm/Building/FixupActions/MakeTypeNonAbstractAction.cs
index 2414e810d..6db0a2e12 100644
--- a/Orm/Xtensive.Orm/Orm/Building/FixupActions/MakeTypeNonAbstractAction.cs
+++ b/Orm/Xtensive.Orm/Orm/Building/FixupActions/MakeTypeNonAbstractAction.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2010.09.08
 
-using System;
 using Xtensive.Orm.Building.Definitions;
 
 namespace Xtensive.Orm.Building.FixupActions
diff --git a/Orm/Xtensive.Orm/Orm/Building/ModelInspectionResult.cs b/Orm/Xtensive.Orm/Orm/Building/ModelInspectionResult.cs
index e9b21385b..3c13cd34d 100644
--- a/Orm/Xtensive.Orm/Orm/Building/ModelInspectionResult.cs
+++ b/Orm/Xtensive.Orm/Orm/Building/ModelInspectionResult.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2009.05.28
 
-using System.Collections.Generic;
 using Xtensive.Orm.Building.Definitions;
 using Xtensive.Orm.Building.FixupActions;
 
diff --git a/Orm/Xtensive.Orm/Orm/Building/ModelInspector.cs b/Orm/Xtensive.Orm/Orm/Building/ModelInspector.cs
index f559958b1..e1f17c552 100644
--- a/Orm/Xtensive.Orm/Orm/Building/ModelInspector.cs
+++ b/Orm/Xtensive.Orm/Orm/Building/ModelInspector.cs
@@ -4,9 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2009.02.24
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Reflection;
 using Xtensive.Orm.Building.Definitions;
 using Xtensive.Orm.Building.DependencyGraph;
diff --git a/Orm/Xtensive.Orm/Orm/Building/Module.cs b/Orm/Xtensive.Orm/Orm/Building/Module.cs
index 93caa0b1b..47217ba14 100644
--- a/Orm/Xtensive.Orm/Orm/Building/Module.cs
+++ b/Orm/Xtensive.Orm/Orm/Building/Module.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.09.27
 
-using System;
-using System.Collections.Generic;
 using Xtensive.Orm.Building.Definitions;
 
 namespace Xtensive.Orm.Building
diff --git a/Orm/Xtensive.Orm/Orm/Building/PrefetchActionContainer.cs b/Orm/Xtensive.Orm/Orm/Building/PrefetchActionContainer.cs
index cd69a075d..75234b7db 100644
--- a/Orm/Xtensive.Orm/Orm/Building/PrefetchActionContainer.cs
+++ b/Orm/Xtensive.Orm/Orm/Building/PrefetchActionContainer.cs
@@ -4,10 +4,7 @@
 // Created by: Alexis Kochetov
 // Created:    2010.01.27
 
-using System;
-using System.Collections.Generic;
 using System.Collections.ObjectModel;
-using System.Linq;
 using Xtensive.Core;
 using Xtensive.Orm.Internals.Prefetch;
 using Xtensive.Orm.Model;
diff --git a/Orm/Xtensive.Orm/Orm/Building/SystemModule.cs b/Orm/Xtensive.Orm/Orm/Building/SystemModule.cs
index d50782ea6..0c8dc95ad 100644
--- a/Orm/Xtensive.Orm/Orm/Building/SystemModule.cs
+++ b/Orm/Xtensive.Orm/Orm/Building/SystemModule.cs
@@ -4,8 +4,6 @@
 // Created by: Andrey Turkov
 // Created:    2013.08.21
 
-using System;
-using System.Linq;
 using Xtensive.Orm.Building.Builders;
 using Xtensive.Orm.Building.Definitions;
 using Xtensive.Orm.Metadata;
diff --git a/Orm/Xtensive.Orm/Orm/Building/Validator.cs b/Orm/Xtensive.Orm/Orm/Building/Validator.cs
index e67c40242..e80f37b2c 100644
--- a/Orm/Xtensive.Orm/Orm/Building/Validator.cs
+++ b/Orm/Xtensive.Orm/Orm/Building/Validator.cs
@@ -4,8 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2007.09.12
 
-using System;
-using System.Collections.Generic;
 using System.Text.RegularExpressions;
 using Xtensive.Orm.Building.Definitions;
 using Xtensive.Orm.Internals;
diff --git a/Orm/Xtensive.Orm/Orm/CommandProcessorContextProvider.cs b/Orm/Xtensive.Orm/Orm/CommandProcessorContextProvider.cs
index 10d8b619b..b7888d6c2 100644
--- a/Orm/Xtensive.Orm/Orm/CommandProcessorContextProvider.cs
+++ b/Orm/Xtensive.Orm/Orm/CommandProcessorContextProvider.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2019.07.12
 
-using System;
 using System.Collections.Concurrent;
 using Xtensive.Orm.Providers;
 
diff --git a/Orm/Xtensive.Orm/Orm/Configuration/ConfigurationBase.cs b/Orm/Xtensive.Orm/Orm/Configuration/ConfigurationBase.cs
index 30aed0ce1..d1647aa11 100644
--- a/Orm/Xtensive.Orm/Orm/Configuration/ConfigurationBase.cs
+++ b/Orm/Xtensive.Orm/Orm/Configuration/ConfigurationBase.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.02.22
 
-using System;
 using Xtensive.Core;
 
 
diff --git a/Orm/Xtensive.Orm/Orm/Configuration/DatabaseConfigurationCollection.cs b/Orm/Xtensive.Orm/Orm/Configuration/DatabaseConfigurationCollection.cs
index b7b469f7a..8610a08b1 100644
--- a/Orm/Xtensive.Orm/Orm/Configuration/DatabaseConfigurationCollection.cs
+++ b/Orm/Xtensive.Orm/Orm/Configuration/DatabaseConfigurationCollection.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.02.08
 
-using System;
 using Xtensive.Collections;
 
 namespace Xtensive.Orm.Configuration
diff --git a/Orm/Xtensive.Orm/Orm/Configuration/DomainConfiguration.cs b/Orm/Xtensive.Orm/Orm/Configuration/DomainConfiguration.cs
index 2596f753e..24328d045 100644
--- a/Orm/Xtensive.Orm/Orm/Configuration/DomainConfiguration.cs
+++ b/Orm/Xtensive.Orm/Orm/Configuration/DomainConfiguration.cs
@@ -4,9 +4,7 @@
 // Created by: Dmitri Maximov
 // Created:    2007.08.03
 
-using System;
 using System.Configuration;
-using System.Linq;
 using JetBrains.Annotations;
 using Xtensive.Core;
 using Xtensive.Orm.Configuration.Elements;
diff --git a/Orm/Xtensive.Orm/Orm/Configuration/DomainOptions.cs b/Orm/Xtensive.Orm/Orm/Configuration/DomainOptions.cs
index 3bcae2e32..af211ea17 100644
--- a/Orm/Xtensive.Orm/Orm/Configuration/DomainOptions.cs
+++ b/Orm/Xtensive.Orm/Orm/Configuration/DomainOptions.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2014.03.12
 
-using System;
 
 namespace Xtensive.Orm.Configuration
 {
diff --git a/Orm/Xtensive.Orm/Orm/Configuration/DomainTypeRegistry.cs b/Orm/Xtensive.Orm/Orm/Configuration/DomainTypeRegistry.cs
index 803720f5b..9b6bfce4f 100644
--- a/Orm/Xtensive.Orm/Orm/Configuration/DomainTypeRegistry.cs
+++ b/Orm/Xtensive.Orm/Orm/Configuration/DomainTypeRegistry.cs
@@ -4,10 +4,7 @@
 // Created by: Alex Yakunin
 // Created:    2010.02.03
 
-using System;
-using System.Collections.Generic;
 using Xtensive.Collections;
-using System.Linq;
 using Xtensive.IoC;
 using Xtensive.Orm.Internals;
 using Xtensive.Orm.Upgrade;
diff --git a/Orm/Xtensive.Orm/Orm/Configuration/Elements/DomainConfigurationElement.cs b/Orm/Xtensive.Orm/Orm/Configuration/Elements/DomainConfigurationElement.cs
index 1d7131a5d..07cc9ea2c 100644
--- a/Orm/Xtensive.Orm/Orm/Configuration/Elements/DomainConfigurationElement.cs
+++ b/Orm/Xtensive.Orm/Orm/Configuration/Elements/DomainConfigurationElement.cs
@@ -4,7 +4,6 @@
 // Created by: Aleksey Gamzov
 // Created:    2008.08.11
 
-using System;
 using System.Configuration;
 using Xtensive.Collections;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Orm/Configuration/Elements/IgnoreRuleElement.cs b/Orm/Xtensive.Orm/Orm/Configuration/Elements/IgnoreRuleElement.cs
index 583c2f1bb..5cdd40f07 100644
--- a/Orm/Xtensive.Orm/Orm/Configuration/Elements/IgnoreRuleElement.cs
+++ b/Orm/Xtensive.Orm/Orm/Configuration/Elements/IgnoreRuleElement.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2013.08.16
 
-using System;
 using System.Configuration;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Orm/Configuration/Elements/NamingConventionElement.cs b/Orm/Xtensive.Orm/Orm/Configuration/Elements/NamingConventionElement.cs
index 4e891a8f4..e5289190f 100644
--- a/Orm/Xtensive.Orm/Orm/Configuration/Elements/NamingConventionElement.cs
+++ b/Orm/Xtensive.Orm/Orm/Configuration/Elements/NamingConventionElement.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2008.08.07
 
-using System;
 using System.Configuration;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Orm/Configuration/Elements/SessionConfigurationElement.cs b/Orm/Xtensive.Orm/Orm/Configuration/Elements/SessionConfigurationElement.cs
index 3bab8025e..61608720d 100644
--- a/Orm/Xtensive.Orm/Orm/Configuration/Elements/SessionConfigurationElement.cs
+++ b/Orm/Xtensive.Orm/Orm/Configuration/Elements/SessionConfigurationElement.cs
@@ -4,7 +4,6 @@
 // Created by: Aleksey Gamzov
 // Created:    2008.08.11
 
-using System;
 using System.Configuration;
 using System.IO;
 using System.Transactions;
diff --git a/Orm/Xtensive.Orm/Orm/Configuration/Elements/VersioningConventionElement.cs b/Orm/Xtensive.Orm/Orm/Configuration/Elements/VersioningConventionElement.cs
index 7cb63e06c..a94cd8eb0 100644
--- a/Orm/Xtensive.Orm/Orm/Configuration/Elements/VersioningConventionElement.cs
+++ b/Orm/Xtensive.Orm/Orm/Configuration/Elements/VersioningConventionElement.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2018.03.14
 
-using System;
 using System.Configuration;
 
 namespace Xtensive.Orm.Configuration.Elements
diff --git a/Orm/Xtensive.Orm/Orm/Configuration/IgnoreRule.cs b/Orm/Xtensive.Orm/Orm/Configuration/IgnoreRule.cs
index dd8c53c2a..b9495dbe3 100644
--- a/Orm/Xtensive.Orm/Orm/Configuration/IgnoreRule.cs
+++ b/Orm/Xtensive.Orm/Orm/Configuration/IgnoreRule.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2013.08.16
 
-using System;
 using System.Text;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Orm/Configuration/IgnoreRuleCollection.cs b/Orm/Xtensive.Orm/Orm/Configuration/IgnoreRuleCollection.cs
index 4d8698921..e4f426747 100644
--- a/Orm/Xtensive.Orm/Orm/Configuration/IgnoreRuleCollection.cs
+++ b/Orm/Xtensive.Orm/Orm/Configuration/IgnoreRuleCollection.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2013.08.16
 
-using System;
 using Xtensive.Collections;
 
 namespace Xtensive.Orm.Configuration
diff --git a/Orm/Xtensive.Orm/Orm/Configuration/Internals/ConnectionInfoParser.cs b/Orm/Xtensive.Orm/Orm/Configuration/Internals/ConnectionInfoParser.cs
index 452d684ab..fa1ee1131 100644
--- a/Orm/Xtensive.Orm/Orm/Configuration/Internals/ConnectionInfoParser.cs
+++ b/Orm/Xtensive.Orm/Orm/Configuration/Internals/ConnectionInfoParser.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2013.09.27
 
-using System;
 using System.Configuration;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Orm/Configuration/Internals/DomainTypeRegistrationHandler.cs b/Orm/Xtensive.Orm/Orm/Configuration/Internals/DomainTypeRegistrationHandler.cs
index 388e369d6..712f47bc4 100644
--- a/Orm/Xtensive.Orm/Orm/Configuration/Internals/DomainTypeRegistrationHandler.cs
+++ b/Orm/Xtensive.Orm/Orm/Configuration/Internals/DomainTypeRegistrationHandler.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2007.08.21
 
-using System;
 using Xtensive.Collections;
 using Xtensive.Core;
 using Xtensive.Reflection;
diff --git a/Orm/Xtensive.Orm/Orm/Configuration/Internals/MappingRuleConstructionFlow.cs b/Orm/Xtensive.Orm/Orm/Configuration/Internals/MappingRuleConstructionFlow.cs
index c4df884d1..1a1eb6520 100644
--- a/Orm/Xtensive.Orm/Orm/Configuration/Internals/MappingRuleConstructionFlow.cs
+++ b/Orm/Xtensive.Orm/Orm/Configuration/Internals/MappingRuleConstructionFlow.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.02.08
 
-using System.Collections.Generic;
 using System.Reflection;
 
 namespace Xtensive.Orm.Configuration
diff --git a/Orm/Xtensive.Orm/Orm/Configuration/Internals/NodeConfigurationExtensions.cs b/Orm/Xtensive.Orm/Orm/Configuration/Internals/NodeConfigurationExtensions.cs
index 6b19db78d..42bc38859 100644
--- a/Orm/Xtensive.Orm/Orm/Configuration/Internals/NodeConfigurationExtensions.cs
+++ b/Orm/Xtensive.Orm/Orm/Configuration/Internals/NodeConfigurationExtensions.cs
@@ -1,6 +1,3 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Text;
 using Xtensive.Sql.Model;
 
diff --git a/Orm/Xtensive.Orm/Orm/Configuration/KeyGeneratorConfigurationCollection.cs b/Orm/Xtensive.Orm/Orm/Configuration/KeyGeneratorConfigurationCollection.cs
index faa0f1234..d2ecb734c 100644
--- a/Orm/Xtensive.Orm/Orm/Configuration/KeyGeneratorConfigurationCollection.cs
+++ b/Orm/Xtensive.Orm/Orm/Configuration/KeyGeneratorConfigurationCollection.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.03.28
 
-using System;
 using Xtensive.Collections;
 using Xtensive.Reflection;
 
diff --git a/Orm/Xtensive.Orm/Orm/Configuration/LetterCasePolicy.cs b/Orm/Xtensive.Orm/Orm/Configuration/LetterCasePolicy.cs
index b8c3757da..f23ed7bac 100644
--- a/Orm/Xtensive.Orm/Orm/Configuration/LetterCasePolicy.cs
+++ b/Orm/Xtensive.Orm/Orm/Configuration/LetterCasePolicy.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2007.09.04
 
-using System;
 
 namespace Xtensive.Orm.Configuration
 {
diff --git a/Orm/Xtensive.Orm/Orm/Configuration/LinqExtensionRegistration.cs b/Orm/Xtensive.Orm/Orm/Configuration/LinqExtensionRegistration.cs
index 35330064d..a93ca5353 100644
--- a/Orm/Xtensive.Orm/Orm/Configuration/LinqExtensionRegistration.cs
+++ b/Orm/Xtensive.Orm/Orm/Configuration/LinqExtensionRegistration.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2011.10.27
 
-using System;
 using System.Linq.Expressions;
 using System.Reflection;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Orm/Configuration/LinqExtensionRegistry.cs b/Orm/Xtensive.Orm/Orm/Configuration/LinqExtensionRegistry.cs
index 1c4d27c8d..fa82a81be 100644
--- a/Orm/Xtensive.Orm/Orm/Configuration/LinqExtensionRegistry.cs
+++ b/Orm/Xtensive.Orm/Orm/Configuration/LinqExtensionRegistry.cs
@@ -4,11 +4,8 @@
 // Created by: Denis Krjuchkov
 // Created:    2011.10.27
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
 using System.Diagnostics;
-using System.Linq;
 using System.Linq.Expressions;
 using System.Reflection;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Orm/Configuration/LoggingConfiguration.cs b/Orm/Xtensive.Orm/Orm/Configuration/LoggingConfiguration.cs
index 8975e4e86..6bd55aa91 100644
--- a/Orm/Xtensive.Orm/Orm/Configuration/LoggingConfiguration.cs
+++ b/Orm/Xtensive.Orm/Orm/Configuration/LoggingConfiguration.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2013.09.27
 
-using System;
-using System.Collections.Generic;
 using System.Configuration;
 using Xtensive.Core;
 using ConfigurationSection = Xtensive.Orm.Configuration.Elements.ConfigurationSection;
diff --git a/Orm/Xtensive.Orm/Orm/Configuration/MappingRuleCollection.cs b/Orm/Xtensive.Orm/Orm/Configuration/MappingRuleCollection.cs
index a347ad783..65f7a15f5 100644
--- a/Orm/Xtensive.Orm/Orm/Configuration/MappingRuleCollection.cs
+++ b/Orm/Xtensive.Orm/Orm/Configuration/MappingRuleCollection.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.02.07
 
-using System;
 using System.Reflection;
 using Xtensive.Collections;
 
diff --git a/Orm/Xtensive.Orm/Orm/Configuration/NameMappingCollection.cs b/Orm/Xtensive.Orm/Orm/Configuration/NameMappingCollection.cs
index 12569674d..2d4b5cd2b 100644
--- a/Orm/Xtensive.Orm/Orm/Configuration/NameMappingCollection.cs
+++ b/Orm/Xtensive.Orm/Orm/Configuration/NameMappingCollection.cs
@@ -4,9 +4,7 @@
 // Created by: Denis Krjuchkov
 // Created:    2014.03.13
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
 using JetBrains.Annotations;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Orm/Configuration/NamespacePolicy.cs b/Orm/Xtensive.Orm/Orm/Configuration/NamespacePolicy.cs
index d05d6a9d5..738055f82 100644
--- a/Orm/Xtensive.Orm/Orm/Configuration/NamespacePolicy.cs
+++ b/Orm/Xtensive.Orm/Orm/Configuration/NamespacePolicy.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2007.09.04
 
-using System;
 
 namespace Xtensive.Orm.Configuration
 {
diff --git a/Orm/Xtensive.Orm/Orm/Configuration/NamingConvention.cs b/Orm/Xtensive.Orm/Orm/Configuration/NamingConvention.cs
index 461b27427..ddec8df59 100644
--- a/Orm/Xtensive.Orm/Orm/Configuration/NamingConvention.cs
+++ b/Orm/Xtensive.Orm/Orm/Configuration/NamingConvention.cs
@@ -4,8 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2007.09.04
 
-using System;
-using System.Collections.Generic;
 using System.Collections.ObjectModel;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Orm/Configuration/NamingRules.cs b/Orm/Xtensive.Orm/Orm/Configuration/NamingRules.cs
index b7e3651ed..c2c6c3e90 100644
--- a/Orm/Xtensive.Orm/Orm/Configuration/NamingRules.cs
+++ b/Orm/Xtensive.Orm/Orm/Configuration/NamingRules.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2007.09.04
 
-using System;
 
 namespace Xtensive.Orm.Configuration
 {
diff --git a/Orm/Xtensive.Orm/Orm/Configuration/NodeConfiguration.cs b/Orm/Xtensive.Orm/Orm/Configuration/NodeConfiguration.cs
index e18509b4d..21b18797b 100644
--- a/Orm/Xtensive.Orm/Orm/Configuration/NodeConfiguration.cs
+++ b/Orm/Xtensive.Orm/Orm/Configuration/NodeConfiguration.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2014.03.13
 
-using System;
 using Xtensive.Core;
 
 namespace Xtensive.Orm.Configuration
diff --git a/Orm/Xtensive.Orm/Orm/Configuration/ReaderPreloadingPolicy.cs b/Orm/Xtensive.Orm/Orm/Configuration/ReaderPreloadingPolicy.cs
index d8057d9f1..4d2eaf9d9 100644
--- a/Orm/Xtensive.Orm/Orm/Configuration/ReaderPreloadingPolicy.cs
+++ b/Orm/Xtensive.Orm/Orm/Configuration/ReaderPreloadingPolicy.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2010.02.02
 
-using System;
 
 namespace Xtensive.Orm.Configuration
 {
diff --git a/Orm/Xtensive.Orm/Orm/Configuration/SessionConfiguration.cs b/Orm/Xtensive.Orm/Orm/Configuration/SessionConfiguration.cs
index 1107f23c3..000e45492 100644
--- a/Orm/Xtensive.Orm/Orm/Configuration/SessionConfiguration.cs
+++ b/Orm/Xtensive.Orm/Orm/Configuration/SessionConfiguration.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2007.08.29
 
-using System;
 using System.Transactions;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Orm/Configuration/SessionConfigurationCollection.cs b/Orm/Xtensive.Orm/Orm/Configuration/SessionConfigurationCollection.cs
index 42db6d470..8fe52b18c 100644
--- a/Orm/Xtensive.Orm/Orm/Configuration/SessionConfigurationCollection.cs
+++ b/Orm/Xtensive.Orm/Orm/Configuration/SessionConfigurationCollection.cs
@@ -4,9 +4,6 @@
 // Created by: Elena Vakhtina
 // Created:    2008.12.05
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Collections;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Orm/Configuration/SessionOptions.cs b/Orm/Xtensive.Orm/Orm/Configuration/SessionOptions.cs
index 1fd1a6d49..c0ecb6f7d 100644
--- a/Orm/Xtensive.Orm/Orm/Configuration/SessionOptions.cs
+++ b/Orm/Xtensive.Orm/Orm/Configuration/SessionOptions.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.10.06
 
-using System;
 using JetBrains.Annotations;
 
 namespace Xtensive.Orm.Configuration
diff --git a/Orm/Xtensive.Orm/Orm/Configuration/VersioningConvention.cs b/Orm/Xtensive.Orm/Orm/Configuration/VersioningConvention.cs
index 6217c87f4..a77538d41 100644
--- a/Orm/Xtensive.Orm/Orm/Configuration/VersioningConvention.cs
+++ b/Orm/Xtensive.Orm/Orm/Configuration/VersioningConvention.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2018.03.03
 
-using System;
 using Xtensive.Core;
 
 namespace Xtensive.Orm.Configuration
diff --git a/Orm/Xtensive.Orm/Orm/ConnectionErrorEventData.cs b/Orm/Xtensive.Orm/Orm/ConnectionErrorEventData.cs
index 1e8ff7121..29f11807d 100644
--- a/Orm/Xtensive.Orm/Orm/ConnectionErrorEventData.cs
+++ b/Orm/Xtensive.Orm/Orm/ConnectionErrorEventData.cs
@@ -2,7 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
 using System.Data.Common;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Orm/ConnectionInfo.cs b/Orm/Xtensive.Orm/Orm/ConnectionInfo.cs
index e0ccc9765..6dca71219 100644
--- a/Orm/Xtensive.Orm/Orm/ConnectionInfo.cs
+++ b/Orm/Xtensive.Orm/Orm/ConnectionInfo.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.12.17
 
-using System;
 using Xtensive.Core;
 
 
diff --git a/Orm/Xtensive.Orm/Orm/DbCommandEventArgs.cs b/Orm/Xtensive.Orm/Orm/DbCommandEventArgs.cs
index c94355a27..c1d87b4d9 100644
--- a/Orm/Xtensive.Orm/Orm/DbCommandEventArgs.cs
+++ b/Orm/Xtensive.Orm/Orm/DbCommandEventArgs.cs
@@ -2,10 +2,7 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Collections.Generic;
 using System.Data.Common;
-using System.Linq;
 using System.Text;
 
 
diff --git a/Orm/Xtensive.Orm/Orm/DelayedQuery.cs b/Orm/Xtensive.Orm/Orm/DelayedQuery.cs
index b77e2db2c..f9e6c7dc9 100644
--- a/Orm/Xtensive.Orm/Orm/DelayedQuery.cs
+++ b/Orm/Xtensive.Orm/Orm/DelayedQuery.cs
@@ -4,9 +4,6 @@
 // Created by: Alexander Nikolaev
 // Created:    2009.08.19
 
-using System;
-using System.Threading;
-using System.Threading.Tasks;
 using Xtensive.Core;
 using Xtensive.Orm.Linq;
 using Xtensive.Orm.Linq.Materialization;
diff --git a/Orm/Xtensive.Orm/Orm/DelayedQuery{T}.cs b/Orm/Xtensive.Orm/Orm/DelayedQuery{T}.cs
index f800ba3f7..9ce2be48e 100644
--- a/Orm/Xtensive.Orm/Orm/DelayedQuery{T}.cs
+++ b/Orm/Xtensive.Orm/Orm/DelayedQuery{T}.cs
@@ -4,11 +4,7 @@
 // Created by: Alexander Nikolaev
 // Created:    2009.08.19
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
-using System.Threading;
-using System.Threading.Tasks;
 using Xtensive.Core;
 using Xtensive.Orm.Internals;
 using Xtensive.Orm.Linq;
diff --git a/Orm/Xtensive.Orm/Orm/DelayedScalarQuery{T}.cs b/Orm/Xtensive.Orm/Orm/DelayedScalarQuery{T}.cs
index e4e4fe7b5..b1f3b3fca 100644
--- a/Orm/Xtensive.Orm/Orm/DelayedScalarQuery{T}.cs
+++ b/Orm/Xtensive.Orm/Orm/DelayedScalarQuery{T}.cs
@@ -4,9 +4,6 @@
 // Created by: Alexander Nikolaev
 // Created:    2009.08.19
 
-using System;
-using System.Threading;
-using System.Threading.Tasks;
 using Xtensive.Core;
 using Xtensive.Orm.Internals;
 using Xtensive.Orm.Linq;
diff --git a/Orm/Xtensive.Orm/Orm/Domain.cs b/Orm/Xtensive.Orm/Orm/Domain.cs
index 3da42b0a9..914c34055 100644
--- a/Orm/Xtensive.Orm/Orm/Domain.cs
+++ b/Orm/Xtensive.Orm/Orm/Domain.cs
@@ -4,12 +4,8 @@
 // Created by: Dmitri Maximov
 // Created:    2007.08.03
 
-using System;
 using System.Collections.Concurrent;
-using System.Collections.Generic;
 using System.Runtime.ExceptionServices;
-using System.Threading;
-using System.Threading.Tasks;
 using JetBrains.Annotations;
 using Xtensive.Caching;
 using Xtensive.Collections;
diff --git a/Orm/Xtensive.Orm/Orm/DomainBound.cs b/Orm/Xtensive.Orm/Orm/DomainBound.cs
index da0b8a871..7a1cfb164 100644
--- a/Orm/Xtensive.Orm/Orm/DomainBound.cs
+++ b/Orm/Xtensive.Orm/Orm/DomainBound.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2007.08.10
 
-using System;
 using Xtensive.Core;
 
 using Xtensive.IoC;
diff --git a/Orm/Xtensive.Orm/Orm/DomainUpgradeMode.cs b/Orm/Xtensive.Orm/Orm/DomainUpgradeMode.cs
index f99b4375a..cfafad971 100644
--- a/Orm/Xtensive.Orm/Orm/DomainUpgradeMode.cs
+++ b/Orm/Xtensive.Orm/Orm/DomainUpgradeMode.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2007.08.06
 
-using System;
 
 namespace Xtensive.Orm
 {
diff --git a/Orm/Xtensive.Orm/Orm/Entity.cs b/Orm/Xtensive.Orm/Orm/Entity.cs
index 1d5363623..ba90f0716 100644
--- a/Orm/Xtensive.Orm/Orm/Entity.cs
+++ b/Orm/Xtensive.Orm/Orm/Entity.cs
@@ -4,11 +4,8 @@
 // Created by: Dmitri Maximov
 // Created:    2007.08.01
 
-using System;
-using System.Collections.Generic;
 using System.ComponentModel;
 using System.Diagnostics;
-using System.Linq;
 using System.Runtime.Serialization;
 using System.Security;
 using Xtensive.Caching;
diff --git a/Orm/Xtensive.Orm/Orm/EntityEventArgs.cs b/Orm/Xtensive.Orm/Orm/EntityEventArgs.cs
index 5e00fac04..7352ec48e 100644
--- a/Orm/Xtensive.Orm/Orm/EntityEventArgs.cs
+++ b/Orm/Xtensive.Orm/Orm/EntityEventArgs.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2009.06.04
 
-using System;
 
 
 namespace Xtensive.Orm
diff --git a/Orm/Xtensive.Orm/Orm/EntityEventBroker.cs b/Orm/Xtensive.Orm/Orm/EntityEventBroker.cs
index 8c53137a7..bb04d2cae 100644
--- a/Orm/Xtensive.Orm/Orm/EntityEventBroker.cs
+++ b/Orm/Xtensive.Orm/Orm/EntityEventBroker.cs
@@ -4,8 +4,6 @@
 // Created by: Alexander Nikolaev
 // Created:    2009.06.29
 
-using System;
-using System.Collections.Generic;
 using Xtensive.Core;
 using Xtensive.Orm.Model;
 
diff --git a/Orm/Xtensive.Orm/Orm/EntityFieldValueGetCompletedEventArgs.cs b/Orm/Xtensive.Orm/Orm/EntityFieldValueGetCompletedEventArgs.cs
index 5a95931fd..eedfa58f3 100644
--- a/Orm/Xtensive.Orm/Orm/EntityFieldValueGetCompletedEventArgs.cs
+++ b/Orm/Xtensive.Orm/Orm/EntityFieldValueGetCompletedEventArgs.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.10.22
 
-using System;
 
 using Xtensive.Orm.Model;
 
diff --git a/Orm/Xtensive.Orm/Orm/EntityFieldValueSetCompletedEventArgs.cs b/Orm/Xtensive.Orm/Orm/EntityFieldValueSetCompletedEventArgs.cs
index bcd1f1aa5..e837ff202 100644
--- a/Orm/Xtensive.Orm/Orm/EntityFieldValueSetCompletedEventArgs.cs
+++ b/Orm/Xtensive.Orm/Orm/EntityFieldValueSetCompletedEventArgs.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.10.22
 
-using System;
 
 using Xtensive.Orm.Model;
 
diff --git a/Orm/Xtensive.Orm/Orm/EntityRemoveCompletedEventArgs.cs b/Orm/Xtensive.Orm/Orm/EntityRemoveCompletedEventArgs.cs
index f7d8f0d40..ea621547a 100644
--- a/Orm/Xtensive.Orm/Orm/EntityRemoveCompletedEventArgs.cs
+++ b/Orm/Xtensive.Orm/Orm/EntityRemoveCompletedEventArgs.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.10.22
 
-using System;
 
 namespace Xtensive.Orm
 {
diff --git a/Orm/Xtensive.Orm/Orm/EntityRemoveReason.cs b/Orm/Xtensive.Orm/Orm/EntityRemoveReason.cs
index 0c06ca215..cc0b5ec4f 100644
--- a/Orm/Xtensive.Orm/Orm/EntityRemoveReason.cs
+++ b/Orm/Xtensive.Orm/Orm/EntityRemoveReason.cs
@@ -4,9 +4,6 @@
 // Created by: Denis Kudelin
 // Created:    2018.10.12
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Text;
 
 namespace Xtensive.Orm
diff --git a/Orm/Xtensive.Orm/Orm/EntityRemovingEventArgs.cs b/Orm/Xtensive.Orm/Orm/EntityRemovingEventArgs.cs
index 65f52bd17..c1aaf4c93 100644
--- a/Orm/Xtensive.Orm/Orm/EntityRemovingEventArgs.cs
+++ b/Orm/Xtensive.Orm/Orm/EntityRemovingEventArgs.cs
@@ -4,9 +4,6 @@
 // Created by: Denis Kudelin
 // Created:    2018.10.12
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Text;
 
 namespace Xtensive.Orm
diff --git a/Orm/Xtensive.Orm/Orm/EntitySetActionCompletedEventArgs.cs b/Orm/Xtensive.Orm/Orm/EntitySetActionCompletedEventArgs.cs
index 6d0512e51..c04c929b0 100644
--- a/Orm/Xtensive.Orm/Orm/EntitySetActionCompletedEventArgs.cs
+++ b/Orm/Xtensive.Orm/Orm/EntitySetActionCompletedEventArgs.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.10.23
 
-using System;
 using System.Diagnostics;
 
 
diff --git a/Orm/Xtensive.Orm/Orm/EntitySetBase.cs b/Orm/Xtensive.Orm/Orm/EntitySetBase.cs
index 72bd04e79..8f9014241 100644
--- a/Orm/Xtensive.Orm/Orm/EntitySetBase.cs
+++ b/Orm/Xtensive.Orm/Orm/EntitySetBase.cs
@@ -4,11 +4,8 @@
 // Created by: Aleksey Gamzov
 // Created:    2008.09.10
 
-using System;
-using System.Collections.Generic;
 using System.Collections.Specialized;
 using System.ComponentModel;
-using System.Linq;
 using System.Runtime.Serialization;
 using Xtensive.Collections;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Orm/EntitySetEventArgs.cs b/Orm/Xtensive.Orm/Orm/EntitySetEventArgs.cs
index 23a49acd6..aefd42cc2 100644
--- a/Orm/Xtensive.Orm/Orm/EntitySetEventArgs.cs
+++ b/Orm/Xtensive.Orm/Orm/EntitySetEventArgs.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.10.23
 
-using System;
 
 
 namespace Xtensive.Orm
diff --git a/Orm/Xtensive.Orm/Orm/EntitySetItemActionCompletedEventArgs.cs b/Orm/Xtensive.Orm/Orm/EntitySetItemActionCompletedEventArgs.cs
index b482fd442..61656771a 100644
--- a/Orm/Xtensive.Orm/Orm/EntitySetItemActionCompletedEventArgs.cs
+++ b/Orm/Xtensive.Orm/Orm/EntitySetItemActionCompletedEventArgs.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.10.23
 
-using System;
 using System.Diagnostics;
 
 
diff --git a/Orm/Xtensive.Orm/Orm/EntitySetItemEventArgs.cs b/Orm/Xtensive.Orm/Orm/EntitySetItemEventArgs.cs
index 69279686f..5079415ec 100644
--- a/Orm/Xtensive.Orm/Orm/EntitySetItemEventArgs.cs
+++ b/Orm/Xtensive.Orm/Orm/EntitySetItemEventArgs.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.10.23
 
-using System;
 using System.Diagnostics;
 
 
diff --git a/Orm/Xtensive.Orm/Orm/EntitySet{T}.cs b/Orm/Xtensive.Orm/Orm/EntitySet{T}.cs
index 38b3df05b..e4d58d68f 100644
--- a/Orm/Xtensive.Orm/Orm/EntitySet{T}.cs
+++ b/Orm/Xtensive.Orm/Orm/EntitySet{T}.cs
@@ -4,11 +4,8 @@
 // Created by: Aleksey Gamzov
 // Created:    2008.09.10
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
 using System.Diagnostics;
-using System.Linq;
 using System.Linq.Expressions;
 using System.Runtime.Serialization;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Orm/EntityState.cs b/Orm/Xtensive.Orm/Orm/EntityState.cs
index 6c83167a4..b4544c117 100644
--- a/Orm/Xtensive.Orm/Orm/EntityState.cs
+++ b/Orm/Xtensive.Orm/Orm/EntityState.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2008.07.07
 
-using System;
 using System.Diagnostics;
 using Xtensive.Caching;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Orm/EntityVersionInfoChangedEventArgs.cs b/Orm/Xtensive.Orm/Orm/EntityVersionInfoChangedEventArgs.cs
index 6f12559d8..6818713ad 100644
--- a/Orm/Xtensive.Orm/Orm/EntityVersionInfoChangedEventArgs.cs
+++ b/Orm/Xtensive.Orm/Orm/EntityVersionInfoChangedEventArgs.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.10.22
 
-using System;
 
 using Xtensive.Orm.Model;
 
diff --git a/Orm/Xtensive.Orm/Orm/Exceptions/CheckConstraintViolationException.cs b/Orm/Xtensive.Orm/Orm/Exceptions/CheckConstraintViolationException.cs
index ce31836f8..cfcd590e5 100644
--- a/Orm/Xtensive.Orm/Orm/Exceptions/CheckConstraintViolationException.cs
+++ b/Orm/Xtensive.Orm/Orm/Exceptions/CheckConstraintViolationException.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2010.02.08
 
-using System;
 using System.Runtime.Serialization;
 
 
diff --git a/Orm/Xtensive.Orm/Orm/Exceptions/ConnectionErrorException.cs b/Orm/Xtensive.Orm/Orm/Exceptions/ConnectionErrorException.cs
index fbd20ed55..d71b189c3 100644
--- a/Orm/Xtensive.Orm/Orm/Exceptions/ConnectionErrorException.cs
+++ b/Orm/Xtensive.Orm/Orm/Exceptions/ConnectionErrorException.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2010.02.08
 
-using System;
 using System.Runtime.Serialization;
 
 
diff --git a/Orm/Xtensive.Orm/Orm/Exceptions/ConstraintViolationException.cs b/Orm/Xtensive.Orm/Orm/Exceptions/ConstraintViolationException.cs
index a9cc64337..6bc31e90a 100644
--- a/Orm/Xtensive.Orm/Orm/Exceptions/ConstraintViolationException.cs
+++ b/Orm/Xtensive.Orm/Orm/Exceptions/ConstraintViolationException.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2010.02.08
 
-using System;
 using System.Runtime.Serialization;
 
 
diff --git a/Orm/Xtensive.Orm/Orm/Exceptions/DeadlockException.cs b/Orm/Xtensive.Orm/Orm/Exceptions/DeadlockException.cs
index d6a2f139e..4e0983971 100644
--- a/Orm/Xtensive.Orm/Orm/Exceptions/DeadlockException.cs
+++ b/Orm/Xtensive.Orm/Orm/Exceptions/DeadlockException.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2010.02.08
 
-using System;
 using System.Runtime.Serialization;
 
 
diff --git a/Orm/Xtensive.Orm/Orm/Exceptions/DomainBuilderException.cs b/Orm/Xtensive.Orm/Orm/Exceptions/DomainBuilderException.cs
index 9914d961b..4e1ef6312 100644
--- a/Orm/Xtensive.Orm/Orm/Exceptions/DomainBuilderException.cs
+++ b/Orm/Xtensive.Orm/Orm/Exceptions/DomainBuilderException.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2007.09.18
 
-using System;
 using System.Runtime.Serialization;
 
 
diff --git a/Orm/Xtensive.Orm/Orm/Exceptions/OperationTimeoutException.cs b/Orm/Xtensive.Orm/Orm/Exceptions/OperationTimeoutException.cs
index 54c0c353f..05a977b26 100644
--- a/Orm/Xtensive.Orm/Orm/Exceptions/OperationTimeoutException.cs
+++ b/Orm/Xtensive.Orm/Orm/Exceptions/OperationTimeoutException.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2010.02.09
 
-using System;
 using System.Runtime.Serialization;
 
 
diff --git a/Orm/Xtensive.Orm/Orm/Exceptions/ParametersLimitExceededException.cs b/Orm/Xtensive.Orm/Orm/Exceptions/ParametersLimitExceededException.cs
index bdd886c41..fc6baa97c 100644
--- a/Orm/Xtensive.Orm/Orm/Exceptions/ParametersLimitExceededException.cs
+++ b/Orm/Xtensive.Orm/Orm/Exceptions/ParametersLimitExceededException.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2018.11.02
 
-using System;
 
 namespace Xtensive.Orm
 {
diff --git a/Orm/Xtensive.Orm/Orm/Exceptions/QueryTranslationException.cs b/Orm/Xtensive.Orm/Orm/Exceptions/QueryTranslationException.cs
index d41df25d7..500c09cc4 100644
--- a/Orm/Xtensive.Orm/Orm/Exceptions/QueryTranslationException.cs
+++ b/Orm/Xtensive.Orm/Orm/Exceptions/QueryTranslationException.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2009.12.07
 
-using System;
 using System.Runtime.Serialization;
 
 
diff --git a/Orm/Xtensive.Orm/Orm/Exceptions/ReferentialConstraintViolationException.cs b/Orm/Xtensive.Orm/Orm/Exceptions/ReferentialConstraintViolationException.cs
index 4575034b4..88197be60 100644
--- a/Orm/Xtensive.Orm/Orm/Exceptions/ReferentialConstraintViolationException.cs
+++ b/Orm/Xtensive.Orm/Orm/Exceptions/ReferentialConstraintViolationException.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2010.02.08
 
-using System;
 using System.Runtime.Serialization;
 
 
diff --git a/Orm/Xtensive.Orm/Orm/Exceptions/ReferentialIntegrityException.cs b/Orm/Xtensive.Orm/Orm/Exceptions/ReferentialIntegrityException.cs
index 12c3a10e8..fb693dbc3 100644
--- a/Orm/Xtensive.Orm/Orm/Exceptions/ReferentialIntegrityException.cs
+++ b/Orm/Xtensive.Orm/Orm/Exceptions/ReferentialIntegrityException.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2008.07.01
 
-using System;
 using System.Runtime.Serialization;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Orm/Exceptions/ReprocessableException.cs b/Orm/Xtensive.Orm/Orm/Exceptions/ReprocessableException.cs
index eaf24ee30..777b93c2d 100644
--- a/Orm/Xtensive.Orm/Orm/Exceptions/ReprocessableException.cs
+++ b/Orm/Xtensive.Orm/Orm/Exceptions/ReprocessableException.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.08.17
 
-using System;
 using System.Runtime.Serialization;
 
 
diff --git a/Orm/Xtensive.Orm/Orm/Exceptions/SchemaSynchronizationException.cs b/Orm/Xtensive.Orm/Orm/Exceptions/SchemaSynchronizationException.cs
index e99948ba2..a4771283e 100644
--- a/Orm/Xtensive.Orm/Orm/Exceptions/SchemaSynchronizationException.cs
+++ b/Orm/Xtensive.Orm/Orm/Exceptions/SchemaSynchronizationException.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2007.09.18
 
-using System;
 using System.Runtime.Serialization;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Orm/Exceptions/StorageException.cs b/Orm/Xtensive.Orm/Orm/Exceptions/StorageException.cs
index b87759422..4e3a06f85 100644
--- a/Orm/Xtensive.Orm/Orm/Exceptions/StorageException.cs
+++ b/Orm/Xtensive.Orm/Orm/Exceptions/StorageException.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.08.17
 
-using System;
 using System.Runtime.Serialization;
 
 
diff --git a/Orm/Xtensive.Orm/Orm/Exceptions/StorageExceptionInfo.cs b/Orm/Xtensive.Orm/Orm/Exceptions/StorageExceptionInfo.cs
index 4879b0d99..adced7237 100644
--- a/Orm/Xtensive.Orm/Orm/Exceptions/StorageExceptionInfo.cs
+++ b/Orm/Xtensive.Orm/Orm/Exceptions/StorageExceptionInfo.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2011.09.30
 
-using System;
 using System.Text;
 
 using Xtensive.Orm.Model;
diff --git a/Orm/Xtensive.Orm/Orm/Exceptions/SyntaxErrorException.cs b/Orm/Xtensive.Orm/Orm/Exceptions/SyntaxErrorException.cs
index 4706a68fc..95a653ca5 100644
--- a/Orm/Xtensive.Orm/Orm/Exceptions/SyntaxErrorException.cs
+++ b/Orm/Xtensive.Orm/Orm/Exceptions/SyntaxErrorException.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2010.02.08
 
-using System;
 using System.Runtime.Serialization;
 
 
diff --git a/Orm/Xtensive.Orm/Orm/Exceptions/TransactionSerializationFailureException.cs b/Orm/Xtensive.Orm/Orm/Exceptions/TransactionSerializationFailureException.cs
index ae56fb09d..2b0a29219 100644
--- a/Orm/Xtensive.Orm/Orm/Exceptions/TransactionSerializationFailureException.cs
+++ b/Orm/Xtensive.Orm/Orm/Exceptions/TransactionSerializationFailureException.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2010.02.08
 
-using System;
 using System.Runtime.Serialization;
 
 
diff --git a/Orm/Xtensive.Orm/Orm/Exceptions/UniqueConstraintViolationException.cs b/Orm/Xtensive.Orm/Orm/Exceptions/UniqueConstraintViolationException.cs
index cb59f90e4..5ba10ed92 100644
--- a/Orm/Xtensive.Orm/Orm/Exceptions/UniqueConstraintViolationException.cs
+++ b/Orm/Xtensive.Orm/Orm/Exceptions/UniqueConstraintViolationException.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2010.02.08
 
-using System;
 using System.Runtime.Serialization;
 
 
diff --git a/Orm/Xtensive.Orm/Orm/Exceptions/VersionConflictException.cs b/Orm/Xtensive.Orm/Orm/Exceptions/VersionConflictException.cs
index 40dca5518..b6b3e5102 100644
--- a/Orm/Xtensive.Orm/Orm/Exceptions/VersionConflictException.cs
+++ b/Orm/Xtensive.Orm/Orm/Exceptions/VersionConflictException.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.08.17
 
-using System;
 using System.Runtime.Serialization;
 
 
diff --git a/Orm/Xtensive.Orm/Orm/ForeignKeyMode.cs b/Orm/Xtensive.Orm/Orm/ForeignKeyMode.cs
index 98ad4b04e..6a3b4455b 100644
--- a/Orm/Xtensive.Orm/Orm/ForeignKeyMode.cs
+++ b/Orm/Xtensive.Orm/Orm/ForeignKeyMode.cs
@@ -4,7 +4,6 @@
 // Created by: Aleksey Gamzov
 // Created:    2008.12.31
 
-using System;
 
 namespace Xtensive.Orm
 {
diff --git a/Orm/Xtensive.Orm/Orm/FullTextSearchCondition/Interfaces/IGenerationTerm.cs b/Orm/Xtensive.Orm/Orm/FullTextSearchCondition/Interfaces/IGenerationTerm.cs
index 8385288fe..a0488cd21 100644
--- a/Orm/Xtensive.Orm/Orm/FullTextSearchCondition/Interfaces/IGenerationTerm.cs
+++ b/Orm/Xtensive.Orm/Orm/FullTextSearchCondition/Interfaces/IGenerationTerm.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2016.12.08
 
-using System.Collections.Generic;
 
 namespace Xtensive.Orm.FullTextSearchCondition.Interfaces
 {
diff --git a/Orm/Xtensive.Orm/Orm/FullTextSearchCondition/Interfaces/IOperator.cs b/Orm/Xtensive.Orm/Orm/FullTextSearchCondition/Interfaces/IOperator.cs
index 8de834818..49f45bdc6 100644
--- a/Orm/Xtensive.Orm/Orm/FullTextSearchCondition/Interfaces/IOperator.cs
+++ b/Orm/Xtensive.Orm/Orm/FullTextSearchCondition/Interfaces/IOperator.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2016.12.08
 
-using System;
-using System.Collections.Generic;
 using Xtensive.Orm.FullTextSearchCondition.Nodes;
 
 namespace Xtensive.Orm.FullTextSearchCondition.Interfaces
diff --git a/Orm/Xtensive.Orm/Orm/FullTextSearchCondition/Interfaces/IProximityOperandsConstructionFlow.cs b/Orm/Xtensive.Orm/Orm/FullTextSearchCondition/Interfaces/IProximityOperandsConstructionFlow.cs
index 8a554466e..56ca78894 100644
--- a/Orm/Xtensive.Orm/Orm/FullTextSearchCondition/Interfaces/IProximityOperandsConstructionFlow.cs
+++ b/Orm/Xtensive.Orm/Orm/FullTextSearchCondition/Interfaces/IProximityOperandsConstructionFlow.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2016.12.08
 
-using System.Collections.Generic;
 
 namespace Xtensive.Orm.FullTextSearchCondition.Interfaces
 {
diff --git a/Orm/Xtensive.Orm/Orm/FullTextSearchCondition/Interfaces/IProximityTerm.cs b/Orm/Xtensive.Orm/Orm/FullTextSearchCondition/Interfaces/IProximityTerm.cs
index 5263129c0..3eb59d4c2 100644
--- a/Orm/Xtensive.Orm/Orm/FullTextSearchCondition/Interfaces/IProximityTerm.cs
+++ b/Orm/Xtensive.Orm/Orm/FullTextSearchCondition/Interfaces/IProximityTerm.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2016.12.08
 
-using System.Collections.Generic;
 
 namespace Xtensive.Orm.FullTextSearchCondition.Interfaces
 {
diff --git a/Orm/Xtensive.Orm/Orm/FullTextSearchCondition/Interfaces/IWeightedTerm.cs b/Orm/Xtensive.Orm/Orm/FullTextSearchCondition/Interfaces/IWeightedTerm.cs
index f221a17ac..31076f137 100644
--- a/Orm/Xtensive.Orm/Orm/FullTextSearchCondition/Interfaces/IWeightedTerm.cs
+++ b/Orm/Xtensive.Orm/Orm/FullTextSearchCondition/Interfaces/IWeightedTerm.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2016.12.08
 
-using System.Collections.Generic;
 
 namespace Xtensive.Orm.FullTextSearchCondition.Interfaces
 {
diff --git a/Orm/Xtensive.Orm/Orm/FullTextSearchCondition/Interfaces/IWeightedTermConstructionFlow.cs b/Orm/Xtensive.Orm/Orm/FullTextSearchCondition/Interfaces/IWeightedTermConstructionFlow.cs
index 9572c8612..0c22fab7d 100644
--- a/Orm/Xtensive.Orm/Orm/FullTextSearchCondition/Interfaces/IWeightedTermConstructionFlow.cs
+++ b/Orm/Xtensive.Orm/Orm/FullTextSearchCondition/Interfaces/IWeightedTermConstructionFlow.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2016.12.08
 
-using System;
-using System.Collections.Generic;
 
 namespace Xtensive.Orm.FullTextSearchCondition.Interfaces
 {
diff --git a/Orm/Xtensive.Orm/Orm/FullTextSearchCondition/Internals/SearchConditionNodeFactory.cs b/Orm/Xtensive.Orm/Orm/FullTextSearchCondition/Internals/SearchConditionNodeFactory.cs
index 75f6aecbd..9ae6af334 100644
--- a/Orm/Xtensive.Orm/Orm/FullTextSearchCondition/Internals/SearchConditionNodeFactory.cs
+++ b/Orm/Xtensive.Orm/Orm/FullTextSearchCondition/Internals/SearchConditionNodeFactory.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2016.12.08
 
-using System.Collections.Generic;
 using Xtensive.Orm.FullTextSearchCondition.Interfaces;
 using Xtensive.Orm.FullTextSearchCondition.Nodes;
 
diff --git a/Orm/Xtensive.Orm/Orm/FullTextSearchCondition/Nodes/CustomProximityTerm.cs b/Orm/Xtensive.Orm/Orm/FullTextSearchCondition/Nodes/CustomProximityTerm.cs
index 38a8a5549..9cb4faf1e 100644
--- a/Orm/Xtensive.Orm/Orm/FullTextSearchCondition/Nodes/CustomProximityTerm.cs
+++ b/Orm/Xtensive.Orm/Orm/FullTextSearchCondition/Nodes/CustomProximityTerm.cs
@@ -4,9 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2016.12.08
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Core;
 using Xtensive.Orm.FullTextSearchCondition.Interfaces;
 
diff --git a/Orm/Xtensive.Orm/Orm/FullTextSearchCondition/Nodes/GenerationTerm.cs b/Orm/Xtensive.Orm/Orm/FullTextSearchCondition/Nodes/GenerationTerm.cs
index ae7f92cdc..c498d3919 100644
--- a/Orm/Xtensive.Orm/Orm/FullTextSearchCondition/Nodes/GenerationTerm.cs
+++ b/Orm/Xtensive.Orm/Orm/FullTextSearchCondition/Nodes/GenerationTerm.cs
@@ -4,9 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2016.12.08
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Collections;
 using Xtensive.Core;
 using Xtensive.Orm.FullTextSearchCondition.Interfaces;
diff --git a/Orm/Xtensive.Orm/Orm/FullTextSearchCondition/Nodes/GenericProximityTerm.cs b/Orm/Xtensive.Orm/Orm/FullTextSearchCondition/Nodes/GenericProximityTerm.cs
index b265cb747..73fad9afc 100644
--- a/Orm/Xtensive.Orm/Orm/FullTextSearchCondition/Nodes/GenericProximityTerm.cs
+++ b/Orm/Xtensive.Orm/Orm/FullTextSearchCondition/Nodes/GenericProximityTerm.cs
@@ -4,9 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2016.12.08
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Orm.FullTextSearchCondition.Interfaces;
 
 namespace Xtensive.Orm.FullTextSearchCondition.Nodes
diff --git a/Orm/Xtensive.Orm/Orm/FullTextSearchCondition/Nodes/Operator.cs b/Orm/Xtensive.Orm/Orm/FullTextSearchCondition/Nodes/Operator.cs
index d88e1caf7..f72f850fc 100644
--- a/Orm/Xtensive.Orm/Orm/FullTextSearchCondition/Nodes/Operator.cs
+++ b/Orm/Xtensive.Orm/Orm/FullTextSearchCondition/Nodes/Operator.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2016.12.08
 
-using System;
-using System.Collections.Generic;
 using Xtensive.Core;
 using Xtensive.Orm.FullTextSearchCondition.Interfaces;
 using Xtensive.Orm.FullTextSearchCondition.Internals;
diff --git a/Orm/Xtensive.Orm/Orm/FullTextSearchCondition/Nodes/WeightedTerm.cs b/Orm/Xtensive.Orm/Orm/FullTextSearchCondition/Nodes/WeightedTerm.cs
index 9ce27c13f..d37f10820 100644
--- a/Orm/Xtensive.Orm/Orm/FullTextSearchCondition/Nodes/WeightedTerm.cs
+++ b/Orm/Xtensive.Orm/Orm/FullTextSearchCondition/Nodes/WeightedTerm.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2016.12.08
 
-using System.Collections.Generic;
 using Xtensive.Orm.FullTextSearchCondition.Interfaces;
 
 namespace Xtensive.Orm.FullTextSearchCondition.Nodes
diff --git a/Orm/Xtensive.Orm/Orm/FullTextSearchCondition/ProximityOperandEndpoint.cs b/Orm/Xtensive.Orm/Orm/FullTextSearchCondition/ProximityOperandEndpoint.cs
index e8a23d85c..e9aeefa03 100644
--- a/Orm/Xtensive.Orm/Orm/FullTextSearchCondition/ProximityOperandEndpoint.cs
+++ b/Orm/Xtensive.Orm/Orm/FullTextSearchCondition/ProximityOperandEndpoint.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2016.12.08
 
-using System.Collections.Generic;
 using Xtensive.Collections;
 using Xtensive.Orm.FullTextSearchCondition.Interfaces;
 using Xtensive.Orm.FullTextSearchCondition.Internals;
diff --git a/Orm/Xtensive.Orm/Orm/FullTextSearchCondition/WeightedTermEndpoint.cs b/Orm/Xtensive.Orm/Orm/FullTextSearchCondition/WeightedTermEndpoint.cs
index 7db2ffc6e..679a88b5b 100644
--- a/Orm/Xtensive.Orm/Orm/FullTextSearchCondition/WeightedTermEndpoint.cs
+++ b/Orm/Xtensive.Orm/Orm/FullTextSearchCondition/WeightedTermEndpoint.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2016.12.08
 
-using System;
-using System.Collections.Generic;
 using System.Collections.ObjectModel;
 using System.Globalization;
 using Xtensive.Orm.FullTextSearchCondition.Interfaces;
diff --git a/Orm/Xtensive.Orm/Orm/Interfaces/DbConnectionAccessor.cs b/Orm/Xtensive.Orm/Orm/Interfaces/DbConnectionAccessor.cs
index 9c306daf4..5a64fd5e0 100644
--- a/Orm/Xtensive.Orm/Orm/Interfaces/DbConnectionAccessor.cs
+++ b/Orm/Xtensive.Orm/Orm/Interfaces/DbConnectionAccessor.cs
@@ -2,8 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System.Threading;
-using System.Threading.Tasks;
 
 namespace Xtensive.Orm
 {
diff --git a/Orm/Xtensive.Orm/Orm/Interfaces/ICompletableScope.cs b/Orm/Xtensive.Orm/Orm/Interfaces/ICompletableScope.cs
index 2a7b5a73b..bb9d980e0 100644
--- a/Orm/Xtensive.Orm/Orm/Interfaces/ICompletableScope.cs
+++ b/Orm/Xtensive.Orm/Orm/Interfaces/ICompletableScope.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2010.08.04
 
-using System;
 
 namespace Xtensive.Orm
 {
diff --git a/Orm/Xtensive.Orm/Orm/Interfaces/IDbConnectionAccessor.cs b/Orm/Xtensive.Orm/Orm/Interfaces/IDbConnectionAccessor.cs
index 6a7231aa8..ea5b689f1 100644
--- a/Orm/Xtensive.Orm/Orm/Interfaces/IDbConnectionAccessor.cs
+++ b/Orm/Xtensive.Orm/Orm/Interfaces/IDbConnectionAccessor.cs
@@ -2,8 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System.Threading;
-using System.Threading.Tasks;
 
 namespace Xtensive.Orm
 {
diff --git a/Orm/Xtensive.Orm/Orm/Interfaces/IHasVersionRoots.cs b/Orm/Xtensive.Orm/Orm/Interfaces/IHasVersionRoots.cs
index 9ba7d05d7..72b8a908b 100644
--- a/Orm/Xtensive.Orm/Orm/Interfaces/IHasVersionRoots.cs
+++ b/Orm/Xtensive.Orm/Orm/Interfaces/IHasVersionRoots.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.10.07
 
-using System.Collections.Generic;
 
 namespace Xtensive.Orm
 {
diff --git a/Orm/Xtensive.Orm/Orm/Interfaces/IModule2.cs b/Orm/Xtensive.Orm/Orm/Interfaces/IModule2.cs
index aa46cd37d..83c077798 100644
--- a/Orm/Xtensive.Orm/Orm/Interfaces/IModule2.cs
+++ b/Orm/Xtensive.Orm/Orm/Interfaces/IModule2.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.09.27
 
-using System;
-using System.Collections.Generic;
 using Xtensive.Orm.Building;
 
 namespace Xtensive.Orm
diff --git a/Orm/Xtensive.Orm/Orm/Interfaces/IOperation.cs b/Orm/Xtensive.Orm/Orm/Interfaces/IOperation.cs
index ecde9d720..e1cbc4fd3 100644
--- a/Orm/Xtensive.Orm/Orm/Interfaces/IOperation.cs
+++ b/Orm/Xtensive.Orm/Orm/Interfaces/IOperation.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.10.21
 
-using System.Collections.Generic;
 using Xtensive.Collections;
 using Xtensive.Orm.Operations;
 
diff --git a/Orm/Xtensive.Orm/Orm/Interfaces/IOperationLogger.cs b/Orm/Xtensive.Orm/Orm/Interfaces/IOperationLogger.cs
index 37de63212..298220219 100644
--- a/Orm/Xtensive.Orm/Orm/Interfaces/IOperationLogger.cs
+++ b/Orm/Xtensive.Orm/Orm/Interfaces/IOperationLogger.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.10.21
 
-using System.Collections.Generic;
 
 namespace Xtensive.Orm
 {
diff --git a/Orm/Xtensive.Orm/Orm/Interfaces/IOperationSequence.cs b/Orm/Xtensive.Orm/Orm/Interfaces/IOperationSequence.cs
index b841ef821..012a8573c 100644
--- a/Orm/Xtensive.Orm/Orm/Interfaces/IOperationSequence.cs
+++ b/Orm/Xtensive.Orm/Orm/Interfaces/IOperationSequence.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2010.03.01
 
-using System;
-using System.Collections.Generic;
 
 namespace Xtensive.Orm
 {
diff --git a/Orm/Xtensive.Orm/Orm/Interfaces/IQueryRootBuilder.cs b/Orm/Xtensive.Orm/Orm/Interfaces/IQueryRootBuilder.cs
index d8e93ac60..262985df6 100644
--- a/Orm/Xtensive.Orm/Orm/Interfaces/IQueryRootBuilder.cs
+++ b/Orm/Xtensive.Orm/Orm/Interfaces/IQueryRootBuilder.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.02.23
 
-using System;
 using System.Linq.Expressions;
 
 namespace Xtensive.Orm
diff --git a/Orm/Xtensive.Orm/Orm/Interfaces/ISessionSource.cs b/Orm/Xtensive.Orm/Orm/Interfaces/ISessionSource.cs
index a892dbcbd..7bec6a7a0 100644
--- a/Orm/Xtensive.Orm/Orm/Interfaces/ISessionSource.cs
+++ b/Orm/Xtensive.Orm/Orm/Interfaces/ISessionSource.cs
@@ -2,8 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System.Threading;
-using System.Threading.Tasks;
 using Xtensive.Orm;
 using Xtensive.Orm.Configuration;
 
diff --git a/Orm/Xtensive.Orm/Orm/Interfaces/IUniqueOperation.cs b/Orm/Xtensive.Orm/Orm/Interfaces/IUniqueOperation.cs
index 14ef72ad6..55d893e20 100644
--- a/Orm/Xtensive.Orm/Orm/Interfaces/IUniqueOperation.cs
+++ b/Orm/Xtensive.Orm/Orm/Interfaces/IUniqueOperation.cs
@@ -4,7 +4,6 @@
 // Created by: Alexander Nikolaev
 // Created:    2010.02.18
 
-using System;
 using Xtensive.Core;
 
 namespace Xtensive.Orm
diff --git a/Orm/Xtensive.Orm/Orm/Interfaces/IVersionSetProvider.cs b/Orm/Xtensive.Orm/Orm/Interfaces/IVersionSetProvider.cs
index 6761bbd11..69b772acd 100644
--- a/Orm/Xtensive.Orm/Orm/Interfaces/IVersionSetProvider.cs
+++ b/Orm/Xtensive.Orm/Orm/Interfaces/IVersionSetProvider.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2010.07.21
 
-using System.Collections.Generic;
 
 namespace Xtensive.Orm
 {
diff --git a/Orm/Xtensive.Orm/Orm/Interfaces/KeyGenerator.cs b/Orm/Xtensive.Orm/Orm/Interfaces/KeyGenerator.cs
index 096a8e01f..5366e56b2 100644
--- a/Orm/Xtensive.Orm/Orm/Interfaces/KeyGenerator.cs
+++ b/Orm/Xtensive.Orm/Orm/Interfaces/KeyGenerator.cs
@@ -1,4 +1,4 @@
-// Copyright (C) 2012 Xtensive LLC.
+// Copyright (C) 2012 Xtensive LLC.
 // All rights reserved.
 // For conditions of distribution and use, see license.
 // Created by: Denis Krjuchkov
@@ -6,6 +6,7 @@
 
 using Xtensive.Orm.Model;
 using Xtensive.Tuples;
+using Tuple = Xtensive.Tuples.Tuple;
 
 namespace Xtensive.Orm
 {
diff --git a/Orm/Xtensive.Orm/Orm/Interfaces/TemporaryKeyGenerator.cs b/Orm/Xtensive.Orm/Orm/Interfaces/TemporaryKeyGenerator.cs
index b943b73eb..0ca05c918 100644
--- a/Orm/Xtensive.Orm/Orm/Interfaces/TemporaryKeyGenerator.cs
+++ b/Orm/Xtensive.Orm/Orm/Interfaces/TemporaryKeyGenerator.cs
@@ -1,4 +1,4 @@
-// Copyright (C) 2012 Xtensive LLC.
+// Copyright (C) 2012 Xtensive LLC.
 // All rights reserved.
 // For conditions of distribution and use, see license.
 // Created by: Denis Krjuchkov
@@ -6,6 +6,7 @@
 
 using Xtensive.Orm.Configuration;
 using Xtensive.Tuples;
+using Tuple = Xtensive.Tuples.Tuple;
 
 namespace Xtensive.Orm
 {
diff --git a/Orm/Xtensive.Orm/Orm/Internals/Activator.cs b/Orm/Xtensive.Orm/Orm/Internals/Activator.cs
index 36263f173..f4cdc785d 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/Activator.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/Activator.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2008.11.01
 
-using System;
 using System.Collections.Concurrent;
 using System.Reflection;
 using FieldInfo = Xtensive.Orm.Model.FieldInfo;
diff --git a/Orm/Xtensive.Orm/Orm/Internals/ChangeRegistries/EntityChangeRegistry.cs b/Orm/Xtensive.Orm/Orm/Internals/ChangeRegistries/EntityChangeRegistry.cs
index 181628504..d9f1fe0af 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/ChangeRegistries/EntityChangeRegistry.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/ChangeRegistries/EntityChangeRegistry.cs
@@ -4,8 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2008.11.03
 
-using System;
-using System.Collections.Generic;
 
 
 namespace Xtensive.Orm.Internals
diff --git a/Orm/Xtensive.Orm/Orm/Internals/ChangeRegistries/EntitySetChangeRegistry.cs b/Orm/Xtensive.Orm/Orm/Internals/ChangeRegistries/EntitySetChangeRegistry.cs
index 98cc18507..f484c3581 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/ChangeRegistries/EntitySetChangeRegistry.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/ChangeRegistries/EntitySetChangeRegistry.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2014.03.27
 
-using System.Collections.Generic;
 
 namespace Xtensive.Orm.Internals
 {
diff --git a/Orm/Xtensive.Orm/Orm/Internals/ChangeRegistries/NonPairedReferenceChangesRegistry.cs b/Orm/Xtensive.Orm/Orm/Internals/ChangeRegistries/NonPairedReferenceChangesRegistry.cs
index 67039d04f..412685ac4 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/ChangeRegistries/NonPairedReferenceChangesRegistry.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/ChangeRegistries/NonPairedReferenceChangesRegistry.cs
@@ -4,9 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2016.06.21
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Collections;
 using Xtensive.Core;
 using Xtensive.Orm.Model;
diff --git a/Orm/Xtensive.Orm/Orm/Internals/ChangeRegistries/ReferenceFieldsChangesRegistry.cs b/Orm/Xtensive.Orm/Orm/Internals/ChangeRegistries/ReferenceFieldsChangesRegistry.cs
index b7c0eef3e..cd89e3812 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/ChangeRegistries/ReferenceFieldsChangesRegistry.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/ChangeRegistries/ReferenceFieldsChangesRegistry.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2014.04.07
 
-using System.Collections.Generic;
 using Xtensive.Core;
 using Xtensive.Orm.Model;
 
diff --git a/Orm/Xtensive.Orm/Orm/Internals/ChangeRegistries/RegistryItems{T}.cs b/Orm/Xtensive.Orm/Orm/Internals/ChangeRegistries/RegistryItems{T}.cs
index b8a1e1caf..8f34b9a71 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/ChangeRegistries/RegistryItems{T}.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/ChangeRegistries/RegistryItems{T}.cs
@@ -3,7 +3,6 @@
 // See the License.txt file in the project root for more information.
 
 using System.Collections;
-using System.Collections.Generic;
 
 
 namespace Xtensive.Orm.Internals
diff --git a/Orm/Xtensive.Orm/Orm/Internals/CompiledQueryProcessingScope.cs b/Orm/Xtensive.Orm/Orm/Internals/CompiledQueryProcessingScope.cs
index 684a47341..edeaa1054 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/CompiledQueryProcessingScope.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/CompiledQueryProcessingScope.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.04.27
 
-using System;
 using Xtensive.Core;
 using Xtensive.Orm.Linq;
 using Xtensive.Orm.Linq.Expressions.Visitors;
diff --git a/Orm/Xtensive.Orm/Orm/Internals/CompiledQueryRunner.cs b/Orm/Xtensive.Orm/Orm/Internals/CompiledQueryRunner.cs
index 976970451..2dc747606 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/CompiledQueryRunner.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/CompiledQueryRunner.cs
@@ -4,13 +4,8 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.01.27
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Linq.Expressions;
 using System.Reflection;
-using System.Threading;
-using System.Threading.Tasks;
 using Xtensive.Caching;
 using Xtensive.Core;
 using Xtensive.Orm.Linq;
diff --git a/Orm/Xtensive.Orm/Orm/Internals/CompletableScope{T}.cs b/Orm/Xtensive.Orm/Orm/Internals/CompletableScope{T}.cs
index 7ae62743a..430d08724 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/CompletableScope{T}.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/CompletableScope{T}.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2010.08.04
 
-using System;
 
 namespace Xtensive.Orm.Internals
 {
diff --git a/Orm/Xtensive.Orm/Orm/Internals/EntityDataReader.cs b/Orm/Xtensive.Orm/Orm/Internals/EntityDataReader.cs
index 7c80bda48..10bab2009 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/EntityDataReader.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/EntityDataReader.cs
@@ -4,8 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2008.11.02
 
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Caching;
 using Xtensive.Core;
 using Xtensive.Orm.Linq.Materialization;
diff --git a/Orm/Xtensive.Orm/Orm/Internals/EntitySetItem.cs b/Orm/Xtensive.Orm/Orm/Internals/EntitySetItem.cs
index 154cbe639..66f3ca30a 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/EntitySetItem.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/EntitySetItem.cs
@@ -4,7 +4,6 @@
 // Created by: Aleksey Gamzov
 // Created:    2008.09.05
 
-using System;
 using Xtensive.Orm.Weaving;
 using Xtensive.Tuples;
 using Tuple = Xtensive.Tuples.Tuple;
diff --git a/Orm/Xtensive.Orm/Orm/Internals/EntitySetState.cs b/Orm/Xtensive.Orm/Orm/Internals/EntitySetState.cs
index c7b50b73b..9ad7e3aa1 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/EntitySetState.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/EntitySetState.cs
@@ -4,11 +4,7 @@
 // Created by: Dmitri Maximov
 // Created:    2008.10.14
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
-using System.Linq;
-using System.Threading;
 using Xtensive.Caching;
 using Xtensive.Core;
 using KeyCache = Xtensive.Caching.ICache<Xtensive.Orm.Key, Xtensive.Orm.Key>;
diff --git a/Orm/Xtensive.Orm/Orm/Internals/EntitySetTypeState.cs b/Orm/Xtensive.Orm/Orm/Internals/EntitySetTypeState.cs
index 29c75b99f..e072ecaeb 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/EntitySetTypeState.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/EntitySetTypeState.cs
@@ -4,7 +4,6 @@
 // Created by: Alexander Nikolaev
 // Created:    2009.08.04
 
-using System;
 using Xtensive.Tuples;
 using Xtensive.Orm.Providers;
 using Xtensive.Orm.Rse.Providers;
diff --git a/Orm/Xtensive.Orm/Orm/Internals/FieldAccessor.cs b/Orm/Xtensive.Orm/Orm/Internals/FieldAccessor.cs
index d2c7a37d2..7837d0735 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/FieldAccessor.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/FieldAccessor.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2010.02.19
 
-using System;
 using System.Diagnostics;
 using Xtensive.Core;
 using Xtensive.Orm.Model;
diff --git a/Orm/Xtensive.Orm/Orm/Internals/FieldAccessorProvider.cs b/Orm/Xtensive.Orm/Orm/Internals/FieldAccessorProvider.cs
index 410ed7a75..0b56c74b8 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/FieldAccessorProvider.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/FieldAccessorProvider.cs
@@ -4,12 +4,10 @@
 // Created by: Alex Yakunin
 // Created:    2010.02.19
 
-using System;
 using System.Reflection;
 using Xtensive.Collections;
 using Xtensive.Orm.Internals.FieldAccessors;
 using Xtensive.Reflection;
-using System.Linq;
 using FieldInfo=Xtensive.Orm.Model.FieldInfo;
 using TypeInfo = Xtensive.Orm.Model.TypeInfo;
 
diff --git a/Orm/Xtensive.Orm/Orm/Internals/FieldAccessors/CachingFieldAccessor.cs b/Orm/Xtensive.Orm/Orm/Internals/FieldAccessors/CachingFieldAccessor.cs
index 91780d522..856153517 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/FieldAccessors/CachingFieldAccessor.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/FieldAccessors/CachingFieldAccessor.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2009.07.08
 
-using System;
 using Xtensive.Orm.Model;
 
 namespace Xtensive.Orm.Internals.FieldAccessors
diff --git a/Orm/Xtensive.Orm/Orm/Internals/FieldAccessors/DefaultFieldAccessor.cs b/Orm/Xtensive.Orm/Orm/Internals/FieldAccessors/DefaultFieldAccessor.cs
index 68bcf6982..2002174bd 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/FieldAccessors/DefaultFieldAccessor.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/FieldAccessors/DefaultFieldAccessor.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2008.05.26
 
-using System;
 using Xtensive.Reflection;
 
 namespace Xtensive.Orm.Internals.FieldAccessors
diff --git a/Orm/Xtensive.Orm/Orm/Internals/FieldAccessors/EntityFieldAccessor.cs b/Orm/Xtensive.Orm/Orm/Internals/FieldAccessors/EntityFieldAccessor.cs
index 5a4cc40d4..22e47f05f 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/FieldAccessors/EntityFieldAccessor.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/FieldAccessors/EntityFieldAccessor.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2008.05.26
 
-using System;
 
 using Xtensive.Tuples;
 
diff --git a/Orm/Xtensive.Orm/Orm/Internals/FieldAccessors/EntitySetFieldAccessor.cs b/Orm/Xtensive.Orm/Orm/Internals/FieldAccessors/EntitySetFieldAccessor.cs
index a4d63046b..35ba9dfd7 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/FieldAccessors/EntitySetFieldAccessor.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/FieldAccessors/EntitySetFieldAccessor.cs
@@ -4,7 +4,6 @@
 // Created by: Aleksey Gamzov
 // Created:    2008.09.05
 
-using System;
 
 namespace Xtensive.Orm.Internals.FieldAccessors
 {
diff --git a/Orm/Xtensive.Orm/Orm/Internals/FieldAccessors/EnumFieldAccessor.cs b/Orm/Xtensive.Orm/Orm/Internals/FieldAccessors/EnumFieldAccessor.cs
index 35580919a..60e6405ed 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/FieldAccessors/EnumFieldAccessor.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/FieldAccessors/EnumFieldAccessor.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2008.06.07
 
-using System;
 using Xtensive.Reflection;
 using Xtensive.Tuples;
 
diff --git a/Orm/Xtensive.Orm/Orm/Internals/FieldAccessors/KeyFieldAccessor.cs b/Orm/Xtensive.Orm/Orm/Internals/FieldAccessors/KeyFieldAccessor.cs
index fc877cb76..7f0b93661 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/FieldAccessors/KeyFieldAccessor.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/FieldAccessors/KeyFieldAccessor.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.11.21
 
-using System;
 using Xtensive.Tuples;
 using Tuple = Xtensive.Tuples.Tuple;
 
diff --git a/Orm/Xtensive.Orm/Orm/Internals/FieldAccessors/StructureFieldAccessor.cs b/Orm/Xtensive.Orm/Orm/Internals/FieldAccessors/StructureFieldAccessor.cs
index 0936daf0b..f24841d9f 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/FieldAccessors/StructureFieldAccessor.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/FieldAccessors/StructureFieldAccessor.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2008.05.30
 
-using System;
 using Xtensive.Core;
 
 using Xtensive.Tuples;
diff --git a/Orm/Xtensive.Orm/Orm/Internals/FieldAccessor{T}.cs b/Orm/Xtensive.Orm/Orm/Internals/FieldAccessor{T}.cs
index 4c83a9b52..e7f8699f0 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/FieldAccessor{T}.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/FieldAccessor{T}.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2008.06.02
 
-using System;
 using Xtensive.Orm.Model;
 
 
diff --git a/Orm/Xtensive.Orm/Orm/Internals/GenericKeyFactory.cs b/Orm/Xtensive.Orm/Orm/Internals/GenericKeyFactory.cs
index 0f4fccbe2..ef944a4d7 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/GenericKeyFactory.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/GenericKeyFactory.cs
@@ -4,8 +4,6 @@
 // Created by: Alexander Nikolaev
 // Created:    2009.07.27
 
-using System;
-using System.Collections.Generic;
 using Xtensive.Orm.Model;
 using Tuple = Xtensive.Tuples.Tuple;
 
diff --git a/Orm/Xtensive.Orm/Orm/Internals/KeyFactory.cs b/Orm/Xtensive.Orm/Orm/Internals/KeyFactory.cs
index 32a8eda87..28340c063 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/KeyFactory.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/KeyFactory.cs
@@ -4,8 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2009.10.09
 
-using System;
-using System.Collections.Generic;
 using Xtensive.Core;
 using Xtensive.Reflection;
 using Xtensive.Tuples;
diff --git a/Orm/Xtensive.Orm/Orm/Internals/KeyGeneratorRegistry.cs b/Orm/Xtensive.Orm/Orm/Internals/KeyGeneratorRegistry.cs
index e6e4b39d2..735e4cbfb 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/KeyGeneratorRegistry.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/KeyGeneratorRegistry.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.03.08
 
-using System.Collections.Generic;
 using Xtensive.Core;
 using Xtensive.Orm.Model;
 
diff --git a/Orm/Xtensive.Orm/Orm/Internals/KeyGenerators/Caching/CachingSequence.cs b/Orm/Xtensive.Orm/Orm/Internals/KeyGenerators/Caching/CachingSequence.cs
index 7654d2375..c8fd2ef8f 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/KeyGenerators/Caching/CachingSequence.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/KeyGenerators/Caching/CachingSequence.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.05.17
 
-using System;
 using Xtensive.Core;
 using Xtensive.Orm.Model;
 using Xtensive.Orm.Providers;
diff --git a/Orm/Xtensive.Orm/Orm/Internals/KeyGenerators/Caching/SessionCachingSequenceProvider.cs b/Orm/Xtensive.Orm/Orm/Internals/KeyGenerators/Caching/SessionCachingSequenceProvider.cs
index eacc00c93..580004d10 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/KeyGenerators/Caching/SessionCachingSequenceProvider.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/KeyGenerators/Caching/SessionCachingSequenceProvider.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.05.17
 
-using System.Collections.Generic;
 using Xtensive.Core;
 using Xtensive.Orm.Model;
 using Xtensive.Orm.Providers;
diff --git a/Orm/Xtensive.Orm/Orm/Internals/KeyGenerators/GloballyUniqueValueGenerator.cs b/Orm/Xtensive.Orm/Orm/Internals/KeyGenerators/GloballyUniqueValueGenerator.cs
index 7a0f2ec2b..e595d662d 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/KeyGenerators/GloballyUniqueValueGenerator.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/KeyGenerators/GloballyUniqueValueGenerator.cs
@@ -1,4 +1,4 @@
-// Copyright (C) 2012 Xtensive LLC.
+// Copyright (C) 2012 Xtensive LLC.
 // All rights reserved.
 // For conditions of distribution and use, see license.
 // Created by: Denis Krjuchkov
@@ -6,6 +6,7 @@
 
 using Xtensive.Orm.Model;
 using Xtensive.Tuples;
+using Tuple = Xtensive.Tuples.Tuple;
 
 namespace Xtensive.Orm.Internals.KeyGenerators
 {
diff --git a/Orm/Xtensive.Orm/Orm/Internals/KeyGenerators/GuidGenerator.cs b/Orm/Xtensive.Orm/Orm/Internals/KeyGenerators/GuidGenerator.cs
index 237f6853c..81e27ac5a 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/KeyGenerators/GuidGenerator.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/KeyGenerators/GuidGenerator.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.03.08
 
-using System;
 
 namespace Xtensive.Orm.Internals.KeyGenerators
 {
diff --git a/Orm/Xtensive.Orm/Orm/Internals/KeyGenerators/StringGenerator.cs b/Orm/Xtensive.Orm/Orm/Internals/KeyGenerators/StringGenerator.cs
index 72aea3db5..3f659f297 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/KeyGenerators/StringGenerator.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/KeyGenerators/StringGenerator.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.03.08
 
-using System;
 
 namespace Xtensive.Orm.Internals.KeyGenerators
 {
diff --git a/Orm/Xtensive.Orm/Orm/Internals/KeyGenerators/TemporarySequentalGenerator.cs b/Orm/Xtensive.Orm/Orm/Internals/KeyGenerators/TemporarySequentalGenerator.cs
index feff88ed6..ac5810ef5 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/KeyGenerators/TemporarySequentalGenerator.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/KeyGenerators/TemporarySequentalGenerator.cs
@@ -1,4 +1,4 @@
-// Copyright (C) 2012 Xtensive LLC.
+// Copyright (C) 2012 Xtensive LLC.
 // All rights reserved.
 // For conditions of distribution and use, see license.
 // Created by: Denis Krjuchkov
@@ -8,6 +8,7 @@
 using Xtensive.Comparison;
 using Xtensive.Orm.Model;
 using Xtensive.Tuples;
+using Tuple = Xtensive.Tuples.Tuple;
 
 namespace Xtensive.Orm.Internals.KeyGenerators
 {
diff --git a/Orm/Xtensive.Orm/Orm/Internals/KeyRemapper.cs b/Orm/Xtensive.Orm/Orm/Internals/KeyRemapper.cs
index 615f42d08..67d65f53a 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/KeyRemapper.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/KeyRemapper.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2014.05.06
 
-using System;
-using System.Linq;
 using Xtensive.Tuples.Transform;
 
 namespace Xtensive.Orm.Internals
diff --git a/Orm/Xtensive.Orm/Orm/Internals/Key{T1,T2,T3,T4}.cs b/Orm/Xtensive.Orm/Orm/Internals/Key{T1,T2,T3,T4}.cs
index 4825bed79..a49ff297f 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/Key{T1,T2,T3,T4}.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/Key{T1,T2,T3,T4}.cs
@@ -4,8 +4,6 @@
 // Created by: Alexander Nikolaev
 // Created:    2009.07.13
 
-using System;
-using System.Collections.Generic;
 using JetBrains.Annotations;
 using Xtensive.Core;
 using Xtensive.Orm.Model;
diff --git a/Orm/Xtensive.Orm/Orm/Internals/Key{T1,T2,T3}.cs b/Orm/Xtensive.Orm/Orm/Internals/Key{T1,T2,T3}.cs
index f1c9fa0a8..9b8f5d960 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/Key{T1,T2,T3}.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/Key{T1,T2,T3}.cs
@@ -4,8 +4,6 @@
 // Created by: Alexander Nikolaev
 // Created:    2009.07.13
 
-using System;
-using System.Collections.Generic;
 using JetBrains.Annotations;
 using Xtensive.Core;
 using Xtensive.Orm.Model;
diff --git a/Orm/Xtensive.Orm/Orm/Internals/Key{T1,T2}.cs b/Orm/Xtensive.Orm/Orm/Internals/Key{T1,T2}.cs
index 9f4834c3e..0b8244c44 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/Key{T1,T2}.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/Key{T1,T2}.cs
@@ -4,8 +4,6 @@
 // Created by: Alexander Nikolaev
 // Created:    2009.07.13
 
-using System;
-using System.Collections.Generic;
 using JetBrains.Annotations;
 using Xtensive.Core;
 using Xtensive.Orm.Model;
diff --git a/Orm/Xtensive.Orm/Orm/Internals/Key{T}.cs b/Orm/Xtensive.Orm/Orm/Internals/Key{T}.cs
index 332f886dc..ac288ee16 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/Key{T}.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/Key{T}.cs
@@ -4,8 +4,6 @@
 // Created by: Alexander Nikolaev
 // Created:    2009.07.13
 
-using System;
-using System.Collections.Generic;
 using JetBrains.Annotations;
 using Xtensive.Core;
 using Xtensive.Orm.Model;
diff --git a/Orm/Xtensive.Orm/Orm/Internals/LongKey.cs b/Orm/Xtensive.Orm/Orm/Internals/LongKey.cs
index 2203651e5..612171ee8 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/LongKey.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/LongKey.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2009.10.20
 
-using System;
 using Xtensive.Orm.Model;
 using Tuple = Xtensive.Tuples.Tuple;
 
diff --git a/Orm/Xtensive.Orm/Orm/Internals/PairIntegrity/SyncAction.cs b/Orm/Xtensive.Orm/Orm/Internals/PairIntegrity/SyncAction.cs
index 4dae8aeeb..375340474 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/PairIntegrity/SyncAction.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/PairIntegrity/SyncAction.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2009.07.15
 
-using System;
 using Xtensive.Core;
 using Xtensive.Orm.Model;
 using Xtensive.Orm.ReferentialIntegrity;
diff --git a/Orm/Xtensive.Orm/Orm/Internals/PairIntegrity/SyncActionSet.cs b/Orm/Xtensive.Orm/Orm/Internals/PairIntegrity/SyncActionSet.cs
index 12135de4e..a2d5ef077 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/PairIntegrity/SyncActionSet.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/PairIntegrity/SyncActionSet.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2008.10.10
 
-using System;
 using Xtensive.Core;
 using Xtensive.Orm.Model;
 using Xtensive.Orm.ReferentialIntegrity;
diff --git a/Orm/Xtensive.Orm/Orm/Internals/PairIntegrity/SyncContext.cs b/Orm/Xtensive.Orm/Orm/Internals/PairIntegrity/SyncContext.cs
index 01eff33a9..4097184e4 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/PairIntegrity/SyncContext.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/PairIntegrity/SyncContext.cs
@@ -4,8 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2008.10.08
 
-using System;
-using System.Collections.Generic;
 using System.ComponentModel;
 using System.Diagnostics;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Orm/Internals/PairIntegrity/SyncManager.cs b/Orm/Xtensive.Orm/Orm/Internals/PairIntegrity/SyncManager.cs
index 9b72b3612..c11fc0044 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/PairIntegrity/SyncManager.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/PairIntegrity/SyncManager.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2008.10.08
 
-using System;
 using Xtensive.Core;
 using Xtensive.Orm.Internals;
 using Xtensive.Orm.Model;
diff --git a/Orm/Xtensive.Orm/Orm/Internals/PersistAction.cs b/Orm/Xtensive.Orm/Orm/Internals/PersistAction.cs
index 9364214d5..f09255049 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/PersistAction.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/PersistAction.cs
@@ -4,7 +4,6 @@
 // Created by: Alexander Nikolaev
 // Created:    2009.07.09
 
-using System;
 using Xtensive.Orm.Providers;
 
 namespace Xtensive.Orm.Internals
diff --git a/Orm/Xtensive.Orm/Orm/Internals/PersistActionGenerator.cs b/Orm/Xtensive.Orm/Orm/Internals/PersistActionGenerator.cs
index 6e57f6f78..205d29e38 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/PersistActionGenerator.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/PersistActionGenerator.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.02.22
 
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Orm.Providers;
 
 namespace Xtensive.Orm.Internals
diff --git a/Orm/Xtensive.Orm/Orm/Internals/Pinner.cs b/Orm/Xtensive.Orm/Orm/Internals/Pinner.cs
index fc73f3f9f..5126a5085 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/Pinner.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/Pinner.cs
@@ -4,9 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.12.11
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Core;
 using Xtensive.Orm.Model;
 
diff --git a/Orm/Xtensive.Orm/Orm/Internals/Prefetch/EntityContainer.cs b/Orm/Xtensive.Orm/Orm/Internals/Prefetch/EntityContainer.cs
index 81e2deac9..347ebdb54 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/Prefetch/EntityContainer.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/Prefetch/EntityContainer.cs
@@ -4,8 +4,6 @@
 // Created by: Alexander Nikolaev
 // Created:    2009.09.04
 
-using System;
-using System.Collections.Generic;
 using Xtensive.Core;
 using Xtensive.Orm.Model;
 using Xtensive.Tuples;
diff --git a/Orm/Xtensive.Orm/Orm/Internals/Prefetch/EntityGroupTask.cs b/Orm/Xtensive.Orm/Orm/Internals/Prefetch/EntityGroupTask.cs
index a500c4abd..1b3f7f19c 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/Prefetch/EntityGroupTask.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/Prefetch/EntityGroupTask.cs
@@ -4,9 +4,6 @@
 // Created by: Alexander Nikolaev
 // Created:    2009.10.20
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Core;
 using Xtensive.Orm.Model;
 using Xtensive.Orm.Rse;
diff --git a/Orm/Xtensive.Orm/Orm/Internals/Prefetch/EntitySetTask.cs b/Orm/Xtensive.Orm/Orm/Internals/Prefetch/EntitySetTask.cs
index b166b1af9..99c795ab5 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/Prefetch/EntitySetTask.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/Prefetch/EntitySetTask.cs
@@ -4,9 +4,6 @@
 // Created by: Alexander Nikolaev
 // Created:    2009.09.09
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Linq.Expressions;
 using System.Reflection;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Orm/Internals/Prefetch/Fetcher.cs b/Orm/Xtensive.Orm/Orm/Internals/Prefetch/Fetcher.cs
index 9cbfff473..0abcf8b02 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/Prefetch/Fetcher.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/Prefetch/Fetcher.cs
@@ -4,10 +4,6 @@
 // Created by: Alexander Nikolaev
 // Created:    2009.10.20
 
-using System.Collections.Generic;
-using System.Linq;
-using System.Threading;
-using System.Threading.Tasks;
 using Xtensive.Collections;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Orm/Internals/Prefetch/GraphContainer.cs b/Orm/Xtensive.Orm/Orm/Internals/Prefetch/GraphContainer.cs
index ed4300d2f..0d014ca49 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/Prefetch/GraphContainer.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/Prefetch/GraphContainer.cs
@@ -4,8 +4,6 @@
 // Created by: Alexander Nikolaev
 // Created:    2009.09.17
 
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Core;
 using Xtensive.Tuples;
 using Xtensive.Orm.Model;
diff --git a/Orm/Xtensive.Orm/Orm/Internals/Prefetch/Nodes/ExpressionMap.cs b/Orm/Xtensive.Orm/Orm/Internals/Prefetch/Nodes/ExpressionMap.cs
index 50d7ed2c8..f413ed37a 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/Prefetch/Nodes/ExpressionMap.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/Prefetch/Nodes/ExpressionMap.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.02.24
 
-using System.Collections.Generic;
-using System.Linq;
 using System.Linq.Expressions;
 using Xtensive.Collections;
 
diff --git a/Orm/Xtensive.Orm/Orm/Internals/Prefetch/Nodes/ExpressionMapBuilder.cs b/Orm/Xtensive.Orm/Orm/Internals/Prefetch/Nodes/ExpressionMapBuilder.cs
index 0d6c2bd7d..92f87a25e 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/Prefetch/Nodes/ExpressionMapBuilder.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/Prefetch/Nodes/ExpressionMapBuilder.cs
@@ -4,9 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.02.24
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Linq.Expressions;
 using System.Reflection;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Orm/Internals/Prefetch/Nodes/IHasNestedNodes.cs b/Orm/Xtensive.Orm/Orm/Internals/Prefetch/Nodes/IHasNestedNodes.cs
index 50d135403..1477093b0 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/Prefetch/Nodes/IHasNestedNodes.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/Prefetch/Nodes/IHasNestedNodes.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2011.01.14
 
-using System.Collections.Generic;
 using System.Collections.ObjectModel;
 
 namespace Xtensive.Orm.Internals.Prefetch
diff --git a/Orm/Xtensive.Orm/Orm/Internals/Prefetch/Nodes/KeyExtractorNode.cs b/Orm/Xtensive.Orm/Orm/Internals/Prefetch/Nodes/KeyExtractorNode.cs
index 9b3af6a0e..f758f83b3 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/Prefetch/Nodes/KeyExtractorNode.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/Prefetch/Nodes/KeyExtractorNode.cs
@@ -4,8 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2011.01.13
 
-using System;
-using System.Collections.Generic;
 using System.Collections.ObjectModel;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Orm/Internals/Prefetch/Nodes/Node.cs b/Orm/Xtensive.Orm/Orm/Internals/Prefetch/Nodes/Node.cs
index 7031d7173..0871ac111 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/Prefetch/Nodes/Node.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/Prefetch/Nodes/Node.cs
@@ -4,8 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2011.01.13
 
-using System;
-using System.Collections.Generic;
 using System.Text;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Orm/Internals/Prefetch/Nodes/NodeAggregator.cs b/Orm/Xtensive.Orm/Orm/Internals/Prefetch/Nodes/NodeAggregator.cs
index d239cce2a..f2703e866 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/Prefetch/Nodes/NodeAggregator.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/Prefetch/Nodes/NodeAggregator.cs
@@ -4,9 +4,7 @@
 // Created by: Alexis Kochetov
 // Created:    2011.01.13
 
-using System.Collections.Generic;
 using System.Collections.ObjectModel;
-using System.Linq;
 
 namespace Xtensive.Orm.Internals.Prefetch
 {
diff --git a/Orm/Xtensive.Orm/Orm/Internals/Prefetch/Nodes/NodeBuilder.cs b/Orm/Xtensive.Orm/Orm/Internals/Prefetch/Nodes/NodeBuilder.cs
index ebc5ad3fa..25d29aded 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/Prefetch/Nodes/NodeBuilder.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/Prefetch/Nodes/NodeBuilder.cs
@@ -4,9 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.02.24
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Linq.Expressions;
 using Xtensive.Collections;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Orm/Internals/Prefetch/Nodes/ReferenceNode.cs b/Orm/Xtensive.Orm/Orm/Internals/Prefetch/Nodes/ReferenceNode.cs
index 5bceb8dc8..f0b4826b6 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/Prefetch/Nodes/ReferenceNode.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/Prefetch/Nodes/ReferenceNode.cs
@@ -4,8 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2010.11.19
 
-using System;
-using System.Collections.Generic;
 using System.Collections.ObjectModel;
 using Xtensive.Orm.Model;
 
diff --git a/Orm/Xtensive.Orm/Orm/Internals/Prefetch/Nodes/SetNode.cs b/Orm/Xtensive.Orm/Orm/Internals/Prefetch/Nodes/SetNode.cs
index 5650ef97a..5645c85e6 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/Prefetch/Nodes/SetNode.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/Prefetch/Nodes/SetNode.cs
@@ -4,8 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2010.11.19
 
-using System;
-using System.Collections.Generic;
 using System.Collections.ObjectModel;
 using Xtensive.Core;
 using Xtensive.Orm.Model;
diff --git a/Orm/Xtensive.Orm/Orm/Internals/Prefetch/PrefetchFieldDescriptor.cs b/Orm/Xtensive.Orm/Orm/Internals/Prefetch/PrefetchFieldDescriptor.cs
index 9d9b41397..9c8e21b73 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/Prefetch/PrefetchFieldDescriptor.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/Prefetch/PrefetchFieldDescriptor.cs
@@ -4,7 +4,6 @@
 // Created by: Alexander Nikolaev
 // Created:    2009.09.23
 
-using System;
 using Xtensive.Core;
 
 using Xtensive.Orm.Model;
diff --git a/Orm/Xtensive.Orm/Orm/Internals/Prefetch/PrefetchHelper.cs b/Orm/Xtensive.Orm/Orm/Internals/Prefetch/PrefetchHelper.cs
index 4bc650e67..19fab1c51 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/Prefetch/PrefetchHelper.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/Prefetch/PrefetchHelper.cs
@@ -4,9 +4,6 @@
 // Created by: Alexander Nikolaev
 // Created:    2009.10.22
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Orm.Model;
 
 namespace Xtensive.Orm.Internals.Prefetch
diff --git a/Orm/Xtensive.Orm/Orm/Internals/Prefetch/PrefetchKeyIterator.cs b/Orm/Xtensive.Orm/Orm/Internals/Prefetch/PrefetchKeyIterator.cs
index 0b5b0029a..86f8ee42e 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/Prefetch/PrefetchKeyIterator.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/Prefetch/PrefetchKeyIterator.cs
@@ -5,8 +5,6 @@
 // Created:    2011.01.11
 
 using System.Collections;
-using System.Collections.Generic;
-using System.Threading;
 
 namespace Xtensive.Orm.Internals.Prefetch
 {
diff --git a/Orm/Xtensive.Orm/Orm/Internals/Prefetch/PrefetchManager.cs b/Orm/Xtensive.Orm/Orm/Internals/Prefetch/PrefetchManager.cs
index d8ac2ebf4..fb16f5235 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/Prefetch/PrefetchManager.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/Prefetch/PrefetchManager.cs
@@ -4,11 +4,6 @@
 // Created by: Alexander Nikolaev
 // Created:    2009.09.03
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Threading;
-using System.Threading.Tasks;
 using Xtensive.Caching;
 using Xtensive.Collections;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Orm/Internals/Prefetch/PrefetchProcessor.cs b/Orm/Xtensive.Orm/Orm/Internals/Prefetch/PrefetchProcessor.cs
index 96e240497..89ce5428e 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/Prefetch/PrefetchProcessor.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/Prefetch/PrefetchProcessor.cs
@@ -4,9 +4,7 @@
 // Created by: Alexis Kochetov
 // Created:    2010.11.22
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
 using System.Diagnostics;
 
 namespace Xtensive.Orm.Internals.Prefetch
diff --git a/Orm/Xtensive.Orm/Orm/Internals/Prefetch/PrefetchQueryAsyncEnumerable.cs b/Orm/Xtensive.Orm/Orm/Internals/Prefetch/PrefetchQueryAsyncEnumerable.cs
index cd553dece..b26249fb4 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/Prefetch/PrefetchQueryAsyncEnumerable.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/Prefetch/PrefetchQueryAsyncEnumerable.cs
@@ -2,11 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Threading;
-using System.Threading.Tasks;
 using Xtensive.Collections;
 using Xtensive.Core;
 using Xtensive.Orm.Model;
diff --git a/Orm/Xtensive.Orm/Orm/Internals/Prefetch/PrefetchQueryEnumerable.cs b/Orm/Xtensive.Orm/Orm/Internals/Prefetch/PrefetchQueryEnumerable.cs
index 012bb5170..ad874f11d 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/Prefetch/PrefetchQueryEnumerable.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/Prefetch/PrefetchQueryEnumerable.cs
@@ -3,10 +3,7 @@
 // See the License.txt file in the project root for more information.
 // Created by: Alexis Kochetov
 // Created:    2010.11.18
-using System;
 using System.Collections;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Collections;
 using Xtensive.Core;
 using Xtensive.Orm.Model;
diff --git a/Orm/Xtensive.Orm/Orm/Internals/Prefetch/ReferencedEntityContainer.cs b/Orm/Xtensive.Orm/Orm/Internals/Prefetch/ReferencedEntityContainer.cs
index b5f6305c0..0fcaa35d5 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/Prefetch/ReferencedEntityContainer.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/Prefetch/ReferencedEntityContainer.cs
@@ -4,9 +4,6 @@
 // Created by: Alexander Nikolaev
 // Created:    2009.09.04
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Core;
 using Xtensive.Tuples;
 using Tuple = Xtensive.Tuples.Tuple;
diff --git a/Orm/Xtensive.Orm/Orm/Internals/Prefetch/RootEntityContainer.cs b/Orm/Xtensive.Orm/Orm/Internals/Prefetch/RootEntityContainer.cs
index dc0a1f7a4..e0a824b49 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/Prefetch/RootEntityContainer.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/Prefetch/RootEntityContainer.cs
@@ -4,7 +4,6 @@
 // Created by: Alexander Nikolaev
 // Created:    2009.09.03
 
-using System;
 using Xtensive.Core;
 using Xtensive.Orm.Model;
 
diff --git a/Orm/Xtensive.Orm/Orm/Internals/Prefetch/StrongReferenceContainer.cs b/Orm/Xtensive.Orm/Orm/Internals/Prefetch/StrongReferenceContainer.cs
index eb01503ba..3c321c0db 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/Prefetch/StrongReferenceContainer.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/Prefetch/StrongReferenceContainer.cs
@@ -4,7 +4,6 @@
 // Created by: Alexander Nikolaev
 // Created:    2009.10.08
 
-using System;
 
 
 namespace Xtensive.Orm.Internals.Prefetch
diff --git a/Orm/Xtensive.Orm/Orm/Internals/QueryTask.cs b/Orm/Xtensive.Orm/Orm/Internals/QueryTask.cs
index 3a9517948..7012c603f 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/QueryTask.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/QueryTask.cs
@@ -4,9 +4,7 @@
 // Created by: Alexander Nikolaev
 // Created:    2009.08.19
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
 using Xtensive.Core;
 using Xtensive.Orm.Rse.Providers;
 using Tuple = Xtensive.Tuples.Tuple;
diff --git a/Orm/Xtensive.Orm/Orm/Internals/ReferentialActions.cs b/Orm/Xtensive.Orm/Orm/Internals/ReferentialActions.cs
index 6f935d8be..253e28d74 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/ReferentialActions.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/ReferentialActions.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2009.07.15
 
-using System;
 using Xtensive.Core;
 using Xtensive.Orm.Model;
 using Xtensive.Orm.PairIntegrity;
diff --git a/Orm/Xtensive.Orm/Orm/Internals/ReferentialIntegrity/ClearActionProcessor.cs b/Orm/Xtensive.Orm/Orm/Internals/ReferentialIntegrity/ClearActionProcessor.cs
index a3011d5fa..4fcd4449e 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/ReferentialIntegrity/ClearActionProcessor.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/ReferentialIntegrity/ClearActionProcessor.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2008.07.01
 
-using System;
 using Xtensive.Orm.Internals;
 using Xtensive.Orm.Model;
 
diff --git a/Orm/Xtensive.Orm/Orm/Internals/ReferentialIntegrity/RemovalContext.cs b/Orm/Xtensive.Orm/Orm/Internals/ReferentialIntegrity/RemovalContext.cs
index f44162d7b..2c239e567 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/ReferentialIntegrity/RemovalContext.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/ReferentialIntegrity/RemovalContext.cs
@@ -4,11 +4,8 @@
 // Created by: Dmitri Maximov
 // Created:    2008.07.02
 
-using System;
-using System.Collections.Generic;
 using Xtensive.Core;
 using Xtensive.Orm.Model;
-using System.Linq;
 
 namespace Xtensive.Orm.ReferentialIntegrity
 {
diff --git a/Orm/Xtensive.Orm/Orm/Internals/ReferentialIntegrity/RemovalProcessor.cs b/Orm/Xtensive.Orm/Orm/Internals/ReferentialIntegrity/RemovalProcessor.cs
index d91a50e11..969dbb2b0 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/ReferentialIntegrity/RemovalProcessor.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/ReferentialIntegrity/RemovalProcessor.cs
@@ -4,9 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2008.07.01
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Core;
 using Xtensive.Orm.Internals;
 using Xtensive.Orm.Model;
diff --git a/Orm/Xtensive.Orm/Orm/Internals/RemapContext.cs b/Orm/Xtensive.Orm/Orm/Internals/RemapContext.cs
index 74c6d882d..a28f5c0ea 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/RemapContext.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/RemapContext.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2014.04.07
 
-using System.Collections.Generic;
 using System.Collections.ObjectModel;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Orm/Internals/SortingPersistActionGenerator.cs b/Orm/Xtensive.Orm/Orm/Internals/SortingPersistActionGenerator.cs
index 5478d81ca..ed296688f 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/SortingPersistActionGenerator.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/SortingPersistActionGenerator.cs
@@ -4,9 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.02.22
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Collections.Graphs;
 using Xtensive.Core;
 using Xtensive.Orm.Model;
diff --git a/Orm/Xtensive.Orm/Orm/Internals/StorageNodeRegistry.cs b/Orm/Xtensive.Orm/Orm/Internals/StorageNodeRegistry.cs
index 8e42e0784..0fe69334d 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/StorageNodeRegistry.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/StorageNodeRegistry.cs
@@ -4,9 +4,7 @@
 // Created by: Denis Krjuchkov
 // Created:    2014.03.13
 
-using System;
 using System.Collections.Concurrent;
-using System.Collections.Generic;
 using Xtensive.Core;
 
 namespace Xtensive.Orm.Internals
diff --git a/Orm/Xtensive.Orm/Orm/Internals/TupleExtensions.cs b/Orm/Xtensive.Orm/Orm/Internals/TupleExtensions.cs
index 9c824c618..6e8ed2f0f 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/TupleExtensions.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/TupleExtensions.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2008.07.29
 
-using System;
 using Xtensive.Core;
 using Xtensive.Tuples;
 using Tuple = Xtensive.Tuples.Tuple;
diff --git a/Orm/Xtensive.Orm/Orm/Internals/TypeMapping.cs b/Orm/Xtensive.Orm/Orm/Internals/TypeMapping.cs
index 9848fbaec..04233194f 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/TypeMapping.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/TypeMapping.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2008.08.08
 
-using System.Collections.Generic;
 using Xtensive.Tuples.Transform;
 using Xtensive.Orm.Model;
 
diff --git a/Orm/Xtensive.Orm/Orm/Internals/VersionGenerator.cs b/Orm/Xtensive.Orm/Orm/Internals/VersionGenerator.cs
index 5093c8aa7..843d4401a 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/VersionGenerator.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/VersionGenerator.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.10.06
 
-using System;
 using Xtensive.Core;
 using Xtensive.Reflection;
 
diff --git a/Orm/Xtensive.Orm/Orm/Internals/WellKnownOrmTypes.cs b/Orm/Xtensive.Orm/Orm/Internals/WellKnownOrmTypes.cs
index 9339d2e43..f33d2eeab 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/WellKnownOrmTypes.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/WellKnownOrmTypes.cs
@@ -2,7 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
 using Xtensive.Core;
 using Xtensive.Orm.Linq;
 using Xtensive.Orm.Linq.Expressions;
diff --git a/Orm/Xtensive.Orm/Orm/Key.cs b/Orm/Xtensive.Orm/Orm/Key.cs
index 893febf90..8e445a1ab 100644
--- a/Orm/Xtensive.Orm/Orm/Key.cs
+++ b/Orm/Xtensive.Orm/Orm/Key.cs
@@ -4,9 +4,7 @@
 // Created by: Alexey Gamzov
 // Created:    2007.12.20
 
-using System;
 using System.Diagnostics;
-using System.Linq;
 using JetBrains.Annotations;
 using Xtensive.Core;
 using Xtensive.Orm.Internals;
diff --git a/Orm/Xtensive.Orm/Orm/KeyEventArgs.cs b/Orm/Xtensive.Orm/Orm/KeyEventArgs.cs
index 4f4db93a8..0b47280e1 100644
--- a/Orm/Xtensive.Orm/Orm/KeyEventArgs.cs
+++ b/Orm/Xtensive.Orm/Orm/KeyEventArgs.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.11.19
 
-using System;
 using System.Diagnostics;
 
 
diff --git a/Orm/Xtensive.Orm/Orm/KeyMapping.cs b/Orm/Xtensive.Orm/Orm/KeyMapping.cs
index 68178f2c3..cc33b6cd1 100644
--- a/Orm/Xtensive.Orm/Orm/KeyMapping.cs
+++ b/Orm/Xtensive.Orm/Orm/KeyMapping.cs
@@ -4,10 +4,7 @@
 // Created by: Alexis Kochetov
 // Created:    2009.11.19
 
-using System;
-using System.Collections.Generic;
 using System.Collections.ObjectModel;
-using System.Linq;
 using System.Runtime.Serialization;
 using System.Security;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Orm/Linq/ColumnExtractionModes.cs b/Orm/Xtensive.Orm/Orm/Linq/ColumnExtractionModes.cs
index 840d5aeec..62fecc9c8 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/ColumnExtractionModes.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/ColumnExtractionModes.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.05.27
 
-using System;
 
 namespace Xtensive.Orm.Linq
 {
diff --git a/Orm/Xtensive.Orm/Orm/Linq/ExpressionEvaluator.cs b/Orm/Xtensive.Orm/Orm/Linq/ExpressionEvaluator.cs
index 51ce8c6bb..da0f69c46 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/ExpressionEvaluator.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/ExpressionEvaluator.cs
@@ -4,9 +4,6 @@
 // Created by: Alexey Kochetov
 // Created:    2008.12.18
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Linq.Expressions;
 using System.Reflection;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Orm/Linq/ExpressionExtensions.cs b/Orm/Xtensive.Orm/Orm/Linq/ExpressionExtensions.cs
index f6273e3e3..e1495ba7b 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/ExpressionExtensions.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/ExpressionExtensions.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Kochetov
 // Created:    2008.12.02
 
-using System;
-using System.Linq;
 using System.Linq.Expressions;
 using System.Reflection;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Orm/Linq/Expressions/ColumnExpression.cs b/Orm/Xtensive.Orm/Orm/Linq/Expressions/ColumnExpression.cs
index 6f997f355..703b6424e 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/Expressions/ColumnExpression.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/Expressions/ColumnExpression.cs
@@ -4,8 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.05.06
 
-using System;
-using System.Collections.Generic;
 using System.Linq.Expressions;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Orm/Linq/Expressions/ConstructorExpression.cs b/Orm/Xtensive.Orm/Orm/Linq/Expressions/ConstructorExpression.cs
index 3b199e6ae..c45c816b3 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/Expressions/ConstructorExpression.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/Expressions/ConstructorExpression.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2009.10.16
 
-using System;
-using System.Collections.Generic;
 using System.Diagnostics;
 using System.Linq.Expressions;
 using System.Reflection;
@@ -13,7 +11,6 @@
 using Xtensive.Core;
 using Xtensive.Orm.Linq.Expressions;
 using Xtensive.Orm.Linq.Expressions.Visitors;
-using System.Linq;
 
 namespace Xtensive.Orm.Linq
 {
diff --git a/Orm/Xtensive.Orm/Orm/Linq/Expressions/EntityExpression.cs b/Orm/Xtensive.Orm/Orm/Linq/Expressions/EntityExpression.cs
index 575b18d80..2a8fade06 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/Expressions/EntityExpression.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/Expressions/EntityExpression.cs
@@ -4,9 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.05.05
 
-using System;
-using System.Linq;
-using System.Collections.Generic;
 using System.Linq.Expressions;
 using Xtensive.Orm.Model;
 
diff --git a/Orm/Xtensive.Orm/Orm/Linq/Expressions/EntityFieldExpression.cs b/Orm/Xtensive.Orm/Orm/Linq/Expressions/EntityFieldExpression.cs
index a6240b64e..f231de87b 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/Expressions/EntityFieldExpression.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/Expressions/EntityFieldExpression.cs
@@ -4,8 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.05.06
 
-using System;
-using System.Collections.Generic;
 using System.Linq.Expressions;
 using Xtensive.Core;
 using Xtensive.Orm.Model;
diff --git a/Orm/Xtensive.Orm/Orm/Linq/Expressions/EntitySetExpression.cs b/Orm/Xtensive.Orm/Orm/Linq/Expressions/EntitySetExpression.cs
index 458ca11bd..9d2683b9e 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/Expressions/EntitySetExpression.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/Expressions/EntitySetExpression.cs
@@ -4,8 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.05.05
 
-using System;
-using System.Collections.Generic;
 using System.Linq.Expressions;
 using Xtensive.Core;
 using Xtensive.Orm.Model;
diff --git a/Orm/Xtensive.Orm/Orm/Linq/Expressions/ExtendedExpression.cs b/Orm/Xtensive.Orm/Orm/Linq/Expressions/ExtendedExpression.cs
index 79d9755d5..0c1dc6df5 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/Expressions/ExtendedExpression.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/Expressions/ExtendedExpression.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.05.06
 
-using System;
 using System.Linq.Expressions;
 
 namespace Xtensive.Orm.Linq.Expressions
diff --git a/Orm/Xtensive.Orm/Orm/Linq/Expressions/ExtendedExpressionType.cs b/Orm/Xtensive.Orm/Orm/Linq/Expressions/ExtendedExpressionType.cs
index fff8f2aad..481cb0906 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/Expressions/ExtendedExpressionType.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/Expressions/ExtendedExpressionType.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.02.05
 
-using System;
 
 namespace Xtensive.Orm.Linq.Expressions
 {
diff --git a/Orm/Xtensive.Orm/Orm/Linq/Expressions/FieldExpression.cs b/Orm/Xtensive.Orm/Orm/Linq/Expressions/FieldExpression.cs
index b5aee9f1d..be5a61c5c 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/Expressions/FieldExpression.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/Expressions/FieldExpression.cs
@@ -4,8 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.05.05
 
-using System;
-using System.Collections.Generic;
 using System.Linq.Expressions;
 using Xtensive.Core;
 using FieldInfo = Xtensive.Orm.Model.FieldInfo;
diff --git a/Orm/Xtensive.Orm/Orm/Linq/Expressions/FullTextExpression.cs b/Orm/Xtensive.Orm/Orm/Linq/Expressions/FullTextExpression.cs
index 2e5477fcd..6df03c476 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/Expressions/FullTextExpression.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/Expressions/FullTextExpression.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2009.12.28
 
-using System;
-using System.Collections.Generic;
 using System.Linq.Expressions;
 using Xtensive.Core;
 using Xtensive.Orm.Internals;
diff --git a/Orm/Xtensive.Orm/Orm/Linq/Expressions/GroupingExpression.cs b/Orm/Xtensive.Orm/Orm/Linq/Expressions/GroupingExpression.cs
index 5f9663e10..9895b7c2d 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/Expressions/GroupingExpression.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/Expressions/GroupingExpression.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2009.05.19
 
-using System;
-using System.Collections.Generic;
 using System.Linq.Expressions;
 using Xtensive.Orm.Linq.Expressions.Visitors;
 using Xtensive.Orm.Rse;
diff --git a/Orm/Xtensive.Orm/Orm/Linq/Expressions/Interfaces/IEntityExpression.cs b/Orm/Xtensive.Orm/Orm/Linq/Expressions/Interfaces/IEntityExpression.cs
index bf295bce1..baf945696 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/Expressions/Interfaces/IEntityExpression.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/Expressions/Interfaces/IEntityExpression.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.05.14
 
-using System;
 namespace Xtensive.Orm.Linq.Expressions
 {
   internal interface IEntityExpression : IPersistentExpression
diff --git a/Orm/Xtensive.Orm/Orm/Linq/Expressions/Interfaces/IMappedExpression.cs b/Orm/Xtensive.Orm/Orm/Linq/Expressions/Interfaces/IMappedExpression.cs
index 2bd7e557f..d77efc0ab 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/Expressions/Interfaces/IMappedExpression.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/Expressions/Interfaces/IMappedExpression.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.05.06
 
-using System.Collections.Generic;
 using System.Linq.Expressions;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Orm/Linq/Expressions/Interfaces/IPersistentExpression.cs b/Orm/Xtensive.Orm/Orm/Linq/Expressions/Interfaces/IPersistentExpression.cs
index 3de123dbc..89fb349dd 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/Expressions/Interfaces/IPersistentExpression.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/Expressions/Interfaces/IPersistentExpression.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.05.06
 
-using System.Collections.Generic;
 using Xtensive.Orm.Model;
 
 namespace Xtensive.Orm.Linq.Expressions
diff --git a/Orm/Xtensive.Orm/Orm/Linq/Expressions/ItemProjectorExpression.cs b/Orm/Xtensive.Orm/Orm/Linq/Expressions/ItemProjectorExpression.cs
index bdd721afb..3cf61632c 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/Expressions/ItemProjectorExpression.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/Expressions/ItemProjectorExpression.cs
@@ -4,8 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.05.06
 
-using System;
-using System.Collections.Generic;
 using System.Linq.Expressions;
 using Xtensive.Core;
 using Xtensive.Orm.Linq.Expressions.Visitors;
diff --git a/Orm/Xtensive.Orm/Orm/Linq/Expressions/KeyExpression.cs b/Orm/Xtensive.Orm/Orm/Linq/Expressions/KeyExpression.cs
index 0d8b6ff21..1688f536e 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/Expressions/KeyExpression.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/Expressions/KeyExpression.cs
@@ -4,8 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.05.05
 
-using System.Collections.Generic;
-using System.Linq;
 using System.Linq.Expressions;
 using System.Reflection;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Orm/Linq/Expressions/LocalCollectionExpression.cs b/Orm/Xtensive.Orm/Orm/Linq/Expressions/LocalCollectionExpression.cs
index 2e2eef558..ac5a6e18a 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/Expressions/LocalCollectionExpression.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/Expressions/LocalCollectionExpression.cs
@@ -4,9 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2009.09.09
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Linq.Expressions;
 using System.Reflection;
 using Xtensive.Collections;
diff --git a/Orm/Xtensive.Orm/Orm/Linq/Expressions/MarkerType.cs b/Orm/Xtensive.Orm/Orm/Linq/Expressions/MarkerType.cs
index 4e8267b51..bac020768 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/Expressions/MarkerType.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/Expressions/MarkerType.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.06.23
 
-using System;
 
 namespace Xtensive.Orm.Linq.Expressions
 {
diff --git a/Orm/Xtensive.Orm/Orm/Linq/Expressions/ParameterizedExpression.cs b/Orm/Xtensive.Orm/Orm/Linq/Expressions/ParameterizedExpression.cs
index d5f627fcb..b5b91c909 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/Expressions/ParameterizedExpression.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/Expressions/ParameterizedExpression.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.05.18
 
-using System;
 using System.Linq.Expressions;
 
 namespace Xtensive.Orm.Linq.Expressions
diff --git a/Orm/Xtensive.Orm/Orm/Linq/Expressions/PersistentFieldExpression.cs b/Orm/Xtensive.Orm/Orm/Linq/Expressions/PersistentFieldExpression.cs
index c718771c1..375fd0a5a 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/Expressions/PersistentFieldExpression.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/Expressions/PersistentFieldExpression.cs
@@ -4,8 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.05.06
 
-using System;
-using System.Collections.Generic;
 using System.Linq.Expressions;
 using System.Reflection;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Orm/Linq/Expressions/ProjectionExpression.cs b/Orm/Xtensive.Orm/Orm/Linq/Expressions/ProjectionExpression.cs
index aa76d8f37..bdf8c1874 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/Expressions/ProjectionExpression.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/Expressions/ProjectionExpression.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Kochetov
 // Created:    2008.12.11
 
-using System;
-using System.Collections.Generic;
 using Xtensive.Core;
 using Tuple = Xtensive.Tuples.Tuple;
 
diff --git a/Orm/Xtensive.Orm/Orm/Linq/Expressions/ResultAccessMethod.cs b/Orm/Xtensive.Orm/Orm/Linq/Expressions/ResultAccessMethod.cs
index 6d910f7bf..f6b1faa3a 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/Expressions/ResultAccessMethod.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/Expressions/ResultAccessMethod.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.04.24
 
-using System;
 
 namespace Xtensive.Orm.Linq.Expressions
 {
diff --git a/Orm/Xtensive.Orm/Orm/Linq/Expressions/StructureExpression.cs b/Orm/Xtensive.Orm/Orm/Linq/Expressions/StructureExpression.cs
index bb31cd358..bfde2b17c 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/Expressions/StructureExpression.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/Expressions/StructureExpression.cs
@@ -4,12 +4,9 @@
 // Created by: Alexey Gamzov
 // Created:    2009.09.29
 
-using System;
-using System.Collections.Generic;
 using System.Linq.Expressions;
 using Xtensive.Core;
 using Xtensive.Orm.Model;
-using System.Linq;
 
 namespace Xtensive.Orm.Linq.Expressions
 {
diff --git a/Orm/Xtensive.Orm/Orm/Linq/Expressions/StructureFieldExpression.cs b/Orm/Xtensive.Orm/Orm/Linq/Expressions/StructureFieldExpression.cs
index f08de19cd..f5dba5177 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/Expressions/StructureFieldExpression.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/Expressions/StructureFieldExpression.cs
@@ -4,12 +4,9 @@
 // Created by: Alexis Kochetov
 // Created:    2009.05.05
 
-using System;
-using System.Collections.Generic;
 using System.Linq.Expressions;
 using Xtensive.Core;
 using Xtensive.Orm.Model;
-using System.Linq;
 
 namespace Xtensive.Orm.Linq.Expressions
 {
diff --git a/Orm/Xtensive.Orm/Orm/Linq/Expressions/SubQueryExpression.cs b/Orm/Xtensive.Orm/Orm/Linq/Expressions/SubQueryExpression.cs
index f34c0312e..4a50b40b0 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/Expressions/SubQueryExpression.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/Expressions/SubQueryExpression.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2009.05.19
 
-using System;
-using System.Collections.Generic;
 using System.Linq.Expressions;
 using Xtensive.Core;
 using Xtensive.Orm.Linq.Expressions.Visitors;
diff --git a/Orm/Xtensive.Orm/Orm/Linq/Expressions/Visitors/ApplyParameterAccessVisitor.cs b/Orm/Xtensive.Orm/Orm/Linq/Expressions/Visitors/ApplyParameterAccessVisitor.cs
index 74032f0e5..9c23b9f35 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/Expressions/Visitors/ApplyParameterAccessVisitor.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/Expressions/Visitors/ApplyParameterAccessVisitor.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.06.02
 
-using System;
 using System.Linq.Expressions;
 using Xtensive.Orm.Rse;
 using ExpressionVisitor = Xtensive.Linq.ExpressionVisitor;
diff --git a/Orm/Xtensive.Orm/Orm/Linq/Expressions/Visitors/ColumnGatherer.cs b/Orm/Xtensive.Orm/Orm/Linq/Expressions/Visitors/ColumnGatherer.cs
index 4516c5a72..62ad42e13 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/Expressions/Visitors/ColumnGatherer.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/Expressions/Visitors/ColumnGatherer.cs
@@ -4,9 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.05.06
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Linq.Expressions;
 using Xtensive.Core;
 using Xtensive.Orm.Rse.Providers;
diff --git a/Orm/Xtensive.Orm/Orm/Linq/Expressions/Visitors/EntityExpressionJoiner.cs b/Orm/Xtensive.Orm/Orm/Linq/Expressions/Visitors/EntityExpressionJoiner.cs
index 756b34757..39a9396a8 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/Expressions/Visitors/EntityExpressionJoiner.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/Expressions/Visitors/EntityExpressionJoiner.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2009.10.02
 
-using System;
 using System.Diagnostics;
 
 namespace Xtensive.Orm.Linq.Expressions.Visitors
diff --git a/Orm/Xtensive.Orm/Orm/Linq/Expressions/Visitors/EnumRewriter.cs b/Orm/Xtensive.Orm/Orm/Linq/Expressions/Visitors/EnumRewriter.cs
index 84d5700c6..7c7422cad 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/Expressions/Visitors/EnumRewriter.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/Expressions/Visitors/EnumRewriter.cs
@@ -2,7 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
 using System.Linq.Expressions;
 using Xtensive.Reflection;
 using ExpressionVisitor = Xtensive.Linq.ExpressionVisitor;
diff --git a/Orm/Xtensive.Orm/Orm/Linq/Expressions/Visitors/ExtendedExpressionReplacer.cs b/Orm/Xtensive.Orm/Orm/Linq/Expressions/Visitors/ExtendedExpressionReplacer.cs
index dfbb2b6a5..5b51c6719 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/Expressions/Visitors/ExtendedExpressionReplacer.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/Expressions/Visitors/ExtendedExpressionReplacer.cs
@@ -4,8 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.04.27
 
-using System;
-using System.Collections.Generic;
 using System.Linq.Expressions;
 using System.Reflection;
 using Xtensive.Orm.Rse.Providers;
diff --git a/Orm/Xtensive.Orm/Orm/Linq/Expressions/Visitors/ExtendedExpressionVisitor.cs b/Orm/Xtensive.Orm/Orm/Linq/Expressions/Visitors/ExtendedExpressionVisitor.cs
index 582b33eb7..83080c16a 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/Expressions/Visitors/ExtendedExpressionVisitor.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/Expressions/Visitors/ExtendedExpressionVisitor.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.05.06
 
-using System;
 using System.Linq.Expressions;
 using Xtensive.Linq;
 using ExpressionVisitor = Xtensive.Linq.ExpressionVisitor;
diff --git a/Orm/Xtensive.Orm/Orm/Linq/Expressions/Visitors/GenericExpressionVisitor.cs b/Orm/Xtensive.Orm/Orm/Linq/Expressions/Visitors/GenericExpressionVisitor.cs
index c017cf801..623d65ae5 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/Expressions/Visitors/GenericExpressionVisitor.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/Expressions/Visitors/GenericExpressionVisitor.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.05.21
 
-using System;
 using System.Linq.Expressions;
 using ExpressionVisitor = Xtensive.Linq.ExpressionVisitor;
 
diff --git a/Orm/Xtensive.Orm/Orm/Linq/Expressions/Visitors/IncludeFilterMappingGatherer.cs b/Orm/Xtensive.Orm/Orm/Linq/Expressions/Visitors/IncludeFilterMappingGatherer.cs
index 7aead4010..84705b9a0 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/Expressions/Visitors/IncludeFilterMappingGatherer.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/Expressions/Visitors/IncludeFilterMappingGatherer.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2009.11.16
 
-using System.Linq;
 using System.Linq.Expressions;
 using Xtensive.Core;
 using Xtensive.Linq;
diff --git a/Orm/Xtensive.Orm/Orm/Linq/Expressions/Visitors/OwnerRemover.cs b/Orm/Xtensive.Orm/Orm/Linq/Expressions/Visitors/OwnerRemover.cs
index 6ec15951c..b4379253a 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/Expressions/Visitors/OwnerRemover.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/Expressions/Visitors/OwnerRemover.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.05.26
 
-using System.Linq;
 using System.Linq.Expressions;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Orm/Linq/Expressions/Visitors/PersistentExpressionVisitor.cs b/Orm/Xtensive.Orm/Orm/Linq/Expressions/Visitors/PersistentExpressionVisitor.cs
index cba7381f4..a75a4fa74 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/Expressions/Visitors/PersistentExpressionVisitor.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/Expressions/Visitors/PersistentExpressionVisitor.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.05.07
 
-using System;
 using System.Linq.Expressions;
 using Xtensive.Core;
 using Xtensive.Orm.Internals;
diff --git a/Orm/Xtensive.Orm/Orm/Linq/FieldExtractor.cs b/Orm/Xtensive.Orm/Orm/Linq/FieldExtractor.cs
index 1a918ac98..9f21ebf90 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/FieldExtractor.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/FieldExtractor.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2016.12.14
 
-using System;
-using System.Linq;
 using System.Linq.Expressions;
 using System.Reflection;
 using Xtensive.Orm.Internals;
diff --git a/Orm/Xtensive.Orm/Orm/Linq/Grouping.cs b/Orm/Xtensive.Orm/Orm/Linq/Grouping.cs
index dbdd873c0..04f87389c 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/Grouping.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/Grouping.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2009.03.17
 
-using System;
-using System.Linq;
 using Xtensive.Core;
 using Xtensive.Orm.Linq.Expressions;
 using Xtensive.Orm.Linq.Materialization;
diff --git a/Orm/Xtensive.Orm/Orm/Linq/ItemToTupleConverter.cs b/Orm/Xtensive.Orm/Orm/Linq/ItemToTupleConverter.cs
index dce583958..a276422bf 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/ItemToTupleConverter.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/ItemToTupleConverter.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2009.10.01
 
-using System;
-using System.Collections.Generic;
 using System.Linq.Expressions;
 using Xtensive.Core;
 using Xtensive.Tuples;
diff --git a/Orm/Xtensive.Orm/Orm/Linq/ItemToTupleConverter{TItem}.cs b/Orm/Xtensive.Orm/Orm/Linq/ItemToTupleConverter{TItem}.cs
index 9e8cc1188..a58e16c66 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/ItemToTupleConverter{TItem}.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/ItemToTupleConverter{TItem}.cs
@@ -4,10 +4,7 @@
 // Created by: Alexey Gamzov
 // Created:    2009.10.01
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
-using System.Linq;
 using System.Linq.Expressions;
 using System.Reflection;
 using Xtensive.Collections;
diff --git a/Orm/Xtensive.Orm/Orm/Linq/LinqBindingCollection.cs b/Orm/Xtensive.Orm/Orm/Linq/LinqBindingCollection.cs
index 17baecb41..4ec63082c 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/LinqBindingCollection.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/LinqBindingCollection.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2009.06.30
 
-using System;
-using System.Collections.Generic;
 using System.Linq.Expressions;
 using Xtensive.Collections;
 using Xtensive.Orm.Linq.Expressions;
diff --git a/Orm/Xtensive.Orm/Orm/Linq/LocalCollectionKeyTypeExtractor.cs b/Orm/Xtensive.Orm/Orm/Linq/LocalCollectionKeyTypeExtractor.cs
index db5884c8d..e560e7302 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/LocalCollectionKeyTypeExtractor.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/LocalCollectionKeyTypeExtractor.cs
@@ -4,9 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2013.12.30
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Linq.Expressions;
 using System.Text;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Orm/Linq/Materialization/ExpressionMaterializer.cs b/Orm/Xtensive.Orm/Orm/Linq/Materialization/ExpressionMaterializer.cs
index a501a3c2e..3a3d50128 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/Materialization/ExpressionMaterializer.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/Materialization/ExpressionMaterializer.cs
@@ -4,9 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2009.05.21
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Linq.Expressions;
 using System.Reflection;
 using Xtensive.Collections;
diff --git a/Orm/Xtensive.Orm/Orm/Linq/Materialization/ItemMaterializer.cs b/Orm/Xtensive.Orm/Orm/Linq/Materialization/ItemMaterializer.cs
index 343b60b6d..1bd264d66 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/Materialization/ItemMaterializer.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/Materialization/ItemMaterializer.cs
@@ -2,7 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
 using Xtensive.Core;
 using Xtensive.Orm.Rse;
 using Xtensive.Tuples;
diff --git a/Orm/Xtensive.Orm/Orm/Linq/Materialization/MaterializationContext.cs b/Orm/Xtensive.Orm/Orm/Linq/Materialization/MaterializationContext.cs
index 0909a1c34..c180b48a5 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/Materialization/MaterializationContext.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/Materialization/MaterializationContext.cs
@@ -4,9 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.05.29
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Core;
 using Xtensive.Tuples.Transform;
 using Xtensive.Orm.Internals;
diff --git a/Orm/Xtensive.Orm/Orm/Linq/Materialization/MaterializationHelper.cs b/Orm/Xtensive.Orm/Orm/Linq/Materialization/MaterializationHelper.cs
index 025523cf8..ad5a8d56c 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/Materialization/MaterializationHelper.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/Materialization/MaterializationHelper.cs
@@ -4,9 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.05.28
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Linq.Expressions;
 using System.Reflection;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Orm/Linq/Materialization/Materializer.cs b/Orm/Xtensive.Orm/Orm/Linq/Materialization/Materializer.cs
index 92787f075..01bdc1a91 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/Materialization/Materializer.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/Materialization/Materializer.cs
@@ -2,7 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
 using Xtensive.Core;
 using Xtensive.Orm.Rse;
 
diff --git a/Orm/Xtensive.Orm/Orm/Linq/Materialization/MaterializingReader.cs b/Orm/Xtensive.Orm/Orm/Linq/Materialization/MaterializingReader.cs
index f1e600fe4..7d3ddf821 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/Materialization/MaterializingReader.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/Materialization/MaterializingReader.cs
@@ -2,10 +2,7 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
-using System.Threading.Tasks;
 using Xtensive.Core;
 using Xtensive.Orm.Rse;
 
diff --git a/Orm/Xtensive.Orm/Orm/Linq/MemberCompilation/Interfaces/IMemberCompilerProvider.cs b/Orm/Xtensive.Orm/Orm/Linq/MemberCompilation/Interfaces/IMemberCompilerProvider.cs
index 0beceb65b..782c564d9 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/MemberCompilation/Interfaces/IMemberCompilerProvider.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/MemberCompilation/Interfaces/IMemberCompilerProvider.cs
@@ -4,7 +4,6 @@
 // Created by: Elena Vakhtina
 // Created:    2009.03.27
 
-using System;
 using System.Reflection;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Orm/Linq/MemberCompilation/Interfaces/IMemberCompilerProvider{T}.cs b/Orm/Xtensive.Orm/Orm/Linq/MemberCompilation/Interfaces/IMemberCompilerProvider{T}.cs
index fe4976d1f..381d47d5c 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/MemberCompilation/Interfaces/IMemberCompilerProvider{T}.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/MemberCompilation/Interfaces/IMemberCompilerProvider{T}.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.02.09
 
-using System;
-using System.Collections.Generic;
 using System.Reflection;
 
 namespace Xtensive.Orm.Linq.MemberCompilation
diff --git a/Orm/Xtensive.Orm/Orm/Linq/MemberCompilation/MemberCompilerProvider-CreateCompiler.cs b/Orm/Xtensive.Orm/Orm/Linq/MemberCompilation/MemberCompilerProvider-CreateCompiler.cs
index 9f6b5cbc1..b17dcc4e4 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/MemberCompilation/MemberCompilerProvider-CreateCompiler.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/MemberCompilation/MemberCompilerProvider-CreateCompiler.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2010.03.10
 
-using System;
 using System.Reflection;
 using Xtensive.Core;
 using Xtensive.Reflection;
diff --git a/Orm/Xtensive.Orm/Orm/Linq/MemberCompilation/MemberCompilerProvider.cs b/Orm/Xtensive.Orm/Orm/Linq/MemberCompilation/MemberCompilerProvider.cs
index 4a643c3f1..9c0562878 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/MemberCompilation/MemberCompilerProvider.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/MemberCompilation/MemberCompilerProvider.cs
@@ -4,9 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.02.09
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Reflection;
 using Xtensive.Core;
 using Xtensive.Reflection;
diff --git a/Orm/Xtensive.Orm/Orm/Linq/MemberCompilation/MemberCompilerProviderFactory.cs b/Orm/Xtensive.Orm/Orm/Linq/MemberCompilation/MemberCompilerProviderFactory.cs
index 6e646fc6f..9036f5be0 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/MemberCompilation/MemberCompilerProviderFactory.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/MemberCompilation/MemberCompilerProviderFactory.cs
@@ -4,7 +4,6 @@
 // Created by: Elena Vakhtia
 // Created:    2009.03.27
 
-using System;
 using Xtensive.Core;
 using Xtensive.Reflection;
 using Activator = System.Activator;
diff --git a/Orm/Xtensive.Orm/Orm/Linq/MemberType.cs b/Orm/Xtensive.Orm/Orm/Linq/MemberType.cs
index 155d113cb..a2cfc85e7 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/MemberType.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/MemberType.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.01.26
 
-using System;
 
 namespace Xtensive.Orm.Linq
 {
diff --git a/Orm/Xtensive.Orm/Orm/Linq/Model/QueryParser.cs b/Orm/Xtensive.Orm/Orm/Linq/Model/QueryParser.cs
index e92b50f3b..69dbf2393 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/Model/QueryParser.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/Model/QueryParser.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2013.12.11
 
-using System;
 using System.Linq.Expressions;
 using Xtensive.Core;
 using Xtensive.Reflection;
diff --git a/Orm/Xtensive.Orm/Orm/Linq/Model/QueryableMethodInfo.cs b/Orm/Xtensive.Orm/Orm/Linq/Model/QueryableMethodInfo.cs
index 929bd3324..246adb0ac 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/Model/QueryableMethodInfo.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/Model/QueryableMethodInfo.cs
@@ -1,5 +1,3 @@
-using System;
-using System.Linq;
 using System.Linq.Expressions;
 using System.Reflection;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Orm/Linq/ParameterAccessorFactory.cs b/Orm/Xtensive.Orm/Orm/Linq/ParameterAccessorFactory.cs
index 72b56bff0..ddc4223de 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/ParameterAccessorFactory.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/ParameterAccessorFactory.cs
@@ -2,7 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
 using System.Linq.Expressions;
 using System.Reflection;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Orm/Linq/ParameterizedQuery.cs b/Orm/Xtensive.Orm/Orm/Linq/ParameterizedQuery.cs
index 202d2b333..aa80e0a97 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/ParameterizedQuery.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/ParameterizedQuery.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.05.27
 
-using System;
 using Xtensive.Core;
 
 namespace Xtensive.Orm.Linq
diff --git a/Orm/Xtensive.Orm/Orm/Linq/QueryHelper.cs b/Orm/Xtensive.Orm/Orm/Linq/QueryHelper.cs
index 6570c42bd..3feb34446 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/QueryHelper.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/QueryHelper.cs
@@ -4,10 +4,7 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.04.02
 
-using System;
-using System.Collections.Generic;
 using System.Diagnostics;
-using System.Linq;
 using System.Linq.Expressions;
 using System.Reflection;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Orm/Linq/QueryPreprocessor.cs b/Orm/Xtensive.Orm/Orm/Linq/QueryPreprocessor.cs
index e522e4116..37f881553 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/QueryPreprocessor.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/QueryPreprocessor.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.08.20
 
-using System;
 using System.Linq.Expressions;
 
 namespace Xtensive.Orm.Linq
diff --git a/Orm/Xtensive.Orm/Orm/Linq/QueryProvider.cs b/Orm/Xtensive.Orm/Orm/Linq/QueryProvider.cs
index 283875c03..4da545b20 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/QueryProvider.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/QueryProvider.cs
@@ -4,13 +4,9 @@
 // Created by: Alexey Kochetov
 // Created:    2008.11.26
 
-using System;
-using System.Linq;
 using System.Linq.Expressions;
 using System.Reflection;
 using System.Runtime.ExceptionServices;
-using System.Threading;
-using System.Threading.Tasks;
 using Xtensive.Core;
 using Xtensive.Orm.Internals;
 using Xtensive.Orm.Providers;
diff --git a/Orm/Xtensive.Orm/Orm/Linq/Queryable.cs b/Orm/Xtensive.Orm/Orm/Linq/Queryable.cs
index 42affc9d5..aab944bbb 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/Queryable.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/Queryable.cs
@@ -4,13 +4,8 @@
 // Created by: Alexis Kochetov
 // Created:    2009.07.01
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
-using System.Linq;
 using System.Linq.Expressions;
-using System.Threading;
-using System.Threading.Tasks;
 using Xtensive.Core;
 
 namespace Xtensive.Orm.Linq
diff --git a/Orm/Xtensive.Orm/Orm/Linq/RemapContext.cs b/Orm/Xtensive.Orm/Orm/Linq/RemapContext.cs
index 8845b632c..8a4db40ac 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/RemapContext.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/RemapContext.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2009.06.03
 
-using System;
 using System.Diagnostics;
 using System.Linq.Expressions;
 
diff --git a/Orm/Xtensive.Orm/Orm/Linq/RemapScope.cs b/Orm/Xtensive.Orm/Orm/Linq/RemapScope.cs
index 0bdbdf50b..0a3fbe98b 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/RemapScope.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/RemapScope.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2009.06.03
 
-using System;
 using Xtensive.Core;
 
 using Xtensive.IoC;
diff --git a/Orm/Xtensive.Orm/Orm/Linq/Rewriters/AggregateOptimizer.cs b/Orm/Xtensive.Orm/Orm/Linq/Rewriters/AggregateOptimizer.cs
index e522903a2..bb95f5525 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/Rewriters/AggregateOptimizer.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/Rewriters/AggregateOptimizer.cs
@@ -4,9 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2013.12.10
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Linq.Expressions;
 using System.Reflection;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Orm/Linq/Rewriters/ClosureAccessRewriter.cs b/Orm/Xtensive.Orm/Orm/Linq/Rewriters/ClosureAccessRewriter.cs
index eb78edb2e..abcf7d276 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/Rewriters/ClosureAccessRewriter.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/Rewriters/ClosureAccessRewriter.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2009.10.09
 
-using System;
-using System.Linq;
 using System.Linq.Expressions;
 using System.Reflection;
 using Xtensive.Orm.Internals;
diff --git a/Orm/Xtensive.Orm/Orm/Linq/Rewriters/EntitySetAccessRewriter.cs b/Orm/Xtensive.Orm/Orm/Linq/Rewriters/EntitySetAccessRewriter.cs
index d03828779..614bd2a2c 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/Rewriters/EntitySetAccessRewriter.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/Rewriters/EntitySetAccessRewriter.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.04.02
 
-using System;
 using System.Linq.Expressions;
 using System.Reflection;
 using Xtensive.Orm.Internals;
diff --git a/Orm/Xtensive.Orm/Orm/Linq/Rewriters/EqualityRewriter.cs b/Orm/Xtensive.Orm/Orm/Linq/Rewriters/EqualityRewriter.cs
index 99d59d3a8..78f3f3c0e 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/Rewriters/EqualityRewriter.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/Rewriters/EqualityRewriter.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.02.18
 
-using System;
 using System.Linq.Expressions;
 using Xtensive.Reflection;
 using ExpressionVisitor = Xtensive.Linq.ExpressionVisitor;
diff --git a/Orm/Xtensive.Orm/Orm/Linq/Rewriters/ParameterRewriter.cs b/Orm/Xtensive.Orm/Orm/Linq/Rewriters/ParameterRewriter.cs
index d243579e9..2ec5cbe10 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/Rewriters/ParameterRewriter.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/Rewriters/ParameterRewriter.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2009.04.07
 
-using System.Collections.Generic;
 using System.Linq.Expressions;
 using ExpressionVisitor = Xtensive.Linq.ExpressionVisitor;
 
diff --git a/Orm/Xtensive.Orm/Orm/Linq/Rewriters/PersistentIndexerRewriter.cs b/Orm/Xtensive.Orm/Orm/Linq/Rewriters/PersistentIndexerRewriter.cs
index 3b7848dcb..4a4209f04 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/Rewriters/PersistentIndexerRewriter.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/Rewriters/PersistentIndexerRewriter.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2009.12.22
 
-using System;
-using System.Linq;
 using System.Linq.Expressions;
 using System.Reflection;
 using Xtensive.Orm.Internals;
diff --git a/Orm/Xtensive.Orm/Orm/Linq/Rewriters/SelectManySelectorRewriter.cs b/Orm/Xtensive.Orm/Orm/Linq/Rewriters/SelectManySelectorRewriter.cs
index d085f4c61..b89bc4b28 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/Rewriters/SelectManySelectorRewriter.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/Rewriters/SelectManySelectorRewriter.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.07.03
 
-using System.Linq;
 using System.Linq.Expressions;
 using Xtensive.Linq;
 using ExpressionVisitor = Xtensive.Linq.ExpressionVisitor;
diff --git a/Orm/Xtensive.Orm/Orm/Linq/Rewriters/SubqueryDefaultResultRewriter.cs b/Orm/Xtensive.Orm/Orm/Linq/Rewriters/SubqueryDefaultResultRewriter.cs
index 9b9d394df..cbdbd5c9e 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/Rewriters/SubqueryDefaultResultRewriter.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/Rewriters/SubqueryDefaultResultRewriter.cs
@@ -2,8 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Linq;
 using System.Linq.Expressions;
 using System.Reflection;
 using Xtensive.Reflection;
diff --git a/Orm/Xtensive.Orm/Orm/Linq/Rewriters/SubqueryFilterRemover.cs b/Orm/Xtensive.Orm/Orm/Linq/Rewriters/SubqueryFilterRemover.cs
index 53fdc4eb4..8e20c59b8 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/Rewriters/SubqueryFilterRemover.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/Rewriters/SubqueryFilterRemover.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2010.04.27
 
-using System.Collections.Generic;
 using System.Linq.Expressions;
 using Xtensive.Orm.Rse;
 using Xtensive.Orm.Rse.Providers;
diff --git a/Orm/Xtensive.Orm/Orm/Linq/SortExpressionExtractor.cs b/Orm/Xtensive.Orm/Orm/Linq/SortExpressionExtractor.cs
index c8801d594..3889fe0dc 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/SortExpressionExtractor.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/SortExpressionExtractor.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2013.04.29
 
-using System;
-using System.Collections.Generic;
 using System.Linq.Expressions;
 using Xtensive.Collections;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Orm/Linq/SubQuery.cs b/Orm/Xtensive.Orm/Orm/Linq/SubQuery.cs
index 32da8bd58..fa02d61aa 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/SubQuery.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/SubQuery.cs
@@ -4,10 +4,7 @@
 // Created by: Alexey Gamzov
 // Created:    2009.04.23
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
-using System.Linq;
 using System.Linq.Expressions;
 using Xtensive.Collections;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Orm/Linq/TranslatedQuery.cs b/Orm/Xtensive.Orm/Orm/Linq/TranslatedQuery.cs
index ff2b72524..ab09d124b 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/TranslatedQuery.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/TranslatedQuery.cs
@@ -4,11 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.05.27
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Threading;
-using System.Threading.Tasks;
 using Xtensive.Core;
 using Xtensive.Orm.Linq.Expressions;
 using Xtensive.Orm.Linq.Materialization;
diff --git a/Orm/Xtensive.Orm/Orm/Linq/Translator.Expressions.cs b/Orm/Xtensive.Orm/Orm/Linq/Translator.Expressions.cs
index 313edef7f..804799026 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/Translator.Expressions.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/Translator.Expressions.cs
@@ -4,9 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.02.27
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Linq.Expressions;
 using System.Reflection;
 using Xtensive.Collections;
diff --git a/Orm/Xtensive.Orm/Orm/Linq/Translator.Materialization.cs b/Orm/Xtensive.Orm/Orm/Linq/Translator.Materialization.cs
index b01b6e43e..f4af839fa 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/Translator.Materialization.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/Translator.Materialization.cs
@@ -4,9 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.05.28
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Linq.Expressions;
 using System.Reflection;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Orm/Linq/Translator.Queryable.cs b/Orm/Xtensive.Orm/Orm/Linq/Translator.Queryable.cs
index 6c7583db8..a714abc7c 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/Translator.Queryable.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/Translator.Queryable.cs
@@ -4,9 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.02.27
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Linq.Expressions;
 using System.Reflection;
 using Xtensive.Collections;
diff --git a/Orm/Xtensive.Orm/Orm/Linq/TranslatorContext.cs b/Orm/Xtensive.Orm/Orm/Linq/TranslatorContext.cs
index 85f70dedf..551fada07 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/TranslatorContext.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/TranslatorContext.cs
@@ -4,9 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.02.10
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Linq.Expressions;
 using System.Reflection;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Orm/Linq/TranslatorState.cs b/Orm/Xtensive.Orm/Orm/Linq/TranslatorState.cs
index d1a606a69..2fc64513a 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/TranslatorState.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/TranslatorState.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2010.01.21
 
-using System;
 using System.Linq.Expressions;
 using System.Runtime.CompilerServices;
 
diff --git a/Orm/Xtensive.Orm/Orm/Linq/WellKnownMembers.cs b/Orm/Xtensive.Orm/Orm/Linq/WellKnownMembers.cs
index 44d80ecab..9d1752458 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/WellKnownMembers.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/WellKnownMembers.cs
@@ -4,9 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.03.24
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Linq.Expressions;
 using System.Reflection;
 using Xtensive.Collections;
diff --git a/Orm/Xtensive.Orm/Orm/Linq/WellknownMembers.Queryable.cs b/Orm/Xtensive.Orm/Orm/Linq/WellknownMembers.Queryable.cs
index 1c91d3c03..ee5eb1694 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/WellknownMembers.Queryable.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/WellknownMembers.Queryable.cs
@@ -2,8 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Collections.Generic;
 using System.Collections.ObjectModel;
 using System.Reflection;
 using Xtensive.Reflection;
diff --git a/Orm/Xtensive.Orm/Orm/Logging/BaseLog.cs b/Orm/Xtensive.Orm/Orm/Logging/BaseLog.cs
index 523c36c20..12792a21b 100644
--- a/Orm/Xtensive.Orm/Orm/Logging/BaseLog.cs
+++ b/Orm/Xtensive.Orm/Orm/Logging/BaseLog.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2013.10.11
 
-using System;
 using Xtensive.Core;
 
 namespace Xtensive.Orm.Logging
diff --git a/Orm/Xtensive.Orm/Orm/Logging/IndentManager.cs b/Orm/Xtensive.Orm/Orm/Logging/IndentManager.cs
index 03cecc714..a393e7f84 100644
--- a/Orm/Xtensive.Orm/Orm/Logging/IndentManager.cs
+++ b/Orm/Xtensive.Orm/Orm/Logging/IndentManager.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2013.11.11
 
-using System;
-using System.Threading;
 
 namespace Xtensive.Orm.Logging
 {
diff --git a/Orm/Xtensive.Orm/Orm/Logging/Internals/ConsoleWriter.cs b/Orm/Xtensive.Orm/Orm/Logging/Internals/ConsoleWriter.cs
index 670490387..a464cf238 100644
--- a/Orm/Xtensive.Orm/Orm/Logging/Internals/ConsoleWriter.cs
+++ b/Orm/Xtensive.Orm/Orm/Logging/Internals/ConsoleWriter.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2013.09.27
 
-using System;
 
 namespace Xtensive.Orm.Logging
 {
diff --git a/Orm/Xtensive.Orm/Orm/Logging/Internals/DebugOnlyConsoleWriter.cs b/Orm/Xtensive.Orm/Orm/Logging/Internals/DebugOnlyConsoleWriter.cs
index da9c6d7a5..e600cb524 100644
--- a/Orm/Xtensive.Orm/Orm/Logging/Internals/DebugOnlyConsoleWriter.cs
+++ b/Orm/Xtensive.Orm/Orm/Logging/Internals/DebugOnlyConsoleWriter.cs
@@ -4,9 +4,7 @@
 // Created by: Alexey Kulakov
 // Created:    2013.09.27
 
-using System;
 using System.Diagnostics;
-using System.Threading;
 
 namespace Xtensive.Orm.Logging
 {
diff --git a/Orm/Xtensive.Orm/Orm/Logging/Internals/InternalLogProvider.cs b/Orm/Xtensive.Orm/Orm/Logging/Internals/InternalLogProvider.cs
index e16f1e541..e952813e6 100644
--- a/Orm/Xtensive.Orm/Orm/Logging/Internals/InternalLogProvider.cs
+++ b/Orm/Xtensive.Orm/Orm/Logging/Internals/InternalLogProvider.cs
@@ -4,10 +4,7 @@
 // Created by: Alexey Kulakov
 // Created:    2013.09.27
 
-using System;
-using System.Collections.Generic;
 using System.IO;
-using System.Linq;
 using Xtensive.Orm.Configuration;
 
 namespace Xtensive.Orm.Logging
diff --git a/Orm/Xtensive.Orm/Orm/Logging/Internals/NullLog.cs b/Orm/Xtensive.Orm/Orm/Logging/Internals/NullLog.cs
index 66b3fdaeb..2a94d1179 100644
--- a/Orm/Xtensive.Orm/Orm/Logging/Internals/NullLog.cs
+++ b/Orm/Xtensive.Orm/Orm/Logging/Internals/NullLog.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2013.09.27
 
-using System;
 
 namespace Xtensive.Orm.Logging
 {
diff --git a/Orm/Xtensive.Orm/Orm/Logging/Internals/SystemClock.cs b/Orm/Xtensive.Orm/Orm/Logging/Internals/SystemClock.cs
index bb2d30215..56c331314 100644
--- a/Orm/Xtensive.Orm/Orm/Logging/Internals/SystemClock.cs
+++ b/Orm/Xtensive.Orm/Orm/Logging/Internals/SystemClock.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2013.09.20
 
-using System;
 
 namespace Xtensive.Orm.Logging
 {
diff --git a/Orm/Xtensive.Orm/Orm/Logging/LogEventInfo.cs b/Orm/Xtensive.Orm/Orm/Logging/LogEventInfo.cs
index e8346e9cf..31376ded2 100644
--- a/Orm/Xtensive.Orm/Orm/Logging/LogEventInfo.cs
+++ b/Orm/Xtensive.Orm/Orm/Logging/LogEventInfo.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2013.09.27
 
-using System;
 using System.Globalization;
 using System.Text;
 
diff --git a/Orm/Xtensive.Orm/Orm/Logging/LogManager.cs b/Orm/Xtensive.Orm/Orm/Logging/LogManager.cs
index a87682153..544cf0245 100644
--- a/Orm/Xtensive.Orm/Orm/Logging/LogManager.cs
+++ b/Orm/Xtensive.Orm/Orm/Logging/LogManager.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2013.09.20
 
-using System;
 using System.Configuration;
 using Xtensive.Core;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm/Orm/Metadata/Assembly.cs b/Orm/Xtensive.Orm/Orm/Metadata/Assembly.cs
index da4c0ef27..b0c49d4ff 100644
--- a/Orm/Xtensive.Orm/Orm/Metadata/Assembly.cs
+++ b/Orm/Xtensive.Orm/Orm/Metadata/Assembly.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Kofman
 // Created:    2008.12.24
 
-using System;
 
 
 namespace Xtensive.Orm.Metadata
diff --git a/Orm/Xtensive.Orm/Orm/Metadata/Extension.cs b/Orm/Xtensive.Orm/Orm/Metadata/Extension.cs
index 6e0179bd3..c3db6447f 100644
--- a/Orm/Xtensive.Orm/Orm/Metadata/Extension.cs
+++ b/Orm/Xtensive.Orm/Orm/Metadata/Extension.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Kofman
 // Created:    2008.12.24
 
-using System;
 
 namespace Xtensive.Orm.Metadata
 {
diff --git a/Orm/Xtensive.Orm/Orm/Metadata/MetadataBase.cs b/Orm/Xtensive.Orm/Orm/Metadata/MetadataBase.cs
index d006f21e4..f9fad8a4e 100644
--- a/Orm/Xtensive.Orm/Orm/Metadata/MetadataBase.cs
+++ b/Orm/Xtensive.Orm/Orm/Metadata/MetadataBase.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2009.05.14
 
-using System;
 using Xtensive.Core;
 
 using Xtensive.Orm.Model;
diff --git a/Orm/Xtensive.Orm/Orm/Metadata/Type.cs b/Orm/Xtensive.Orm/Orm/Metadata/Type.cs
index a84845dc3..a71c40276 100644
--- a/Orm/Xtensive.Orm/Orm/Metadata/Type.cs
+++ b/Orm/Xtensive.Orm/Orm/Metadata/Type.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Kofman
 // Created:    2008.12.24
 
-using System;
 
 
 namespace Xtensive.Orm.Metadata
diff --git a/Orm/Xtensive.Orm/Orm/Model/AssociationInfo.cs b/Orm/Xtensive.Orm/Orm/Model/AssociationInfo.cs
index e30f4cc7e..42b2dc0b6 100644
--- a/Orm/Xtensive.Orm/Orm/Model/AssociationInfo.cs
+++ b/Orm/Xtensive.Orm/Orm/Model/AssociationInfo.cs
@@ -4,8 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2008.07.02
 
-using System;
-using System.Linq;
 using Xtensive.Core;
 using Xtensive.Tuples.Transform;
 using Tuple = Xtensive.Tuples.Tuple;
diff --git a/Orm/Xtensive.Orm/Orm/Model/AssociationInfoCollection.cs b/Orm/Xtensive.Orm/Orm/Model/AssociationInfoCollection.cs
index f8027b4e4..f12af4bc3 100644
--- a/Orm/Xtensive.Orm/Orm/Model/AssociationInfoCollection.cs
+++ b/Orm/Xtensive.Orm/Orm/Model/AssociationInfoCollection.cs
@@ -4,9 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2008.07.02
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 
 namespace Xtensive.Orm.Model
 {
diff --git a/Orm/Xtensive.Orm/Orm/Model/ColumnAttributes.cs b/Orm/Xtensive.Orm/Orm/Model/ColumnAttributes.cs
index 8e84b1fc0..d9244bc55 100644
--- a/Orm/Xtensive.Orm/Orm/Model/ColumnAttributes.cs
+++ b/Orm/Xtensive.Orm/Orm/Model/ColumnAttributes.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2007.10.03
 
-using System;
 
 namespace Xtensive.Orm.Model
 {
diff --git a/Orm/Xtensive.Orm/Orm/Model/ColumnGroup.cs b/Orm/Xtensive.Orm/Orm/Model/ColumnGroup.cs
index c77ba3312..3ec74c3e8 100644
--- a/Orm/Xtensive.Orm/Orm/Model/ColumnGroup.cs
+++ b/Orm/Xtensive.Orm/Orm/Model/ColumnGroup.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Kochetov
 // Created:    2008.08.01
 
-using System;
-using System.Collections.Generic;
 using System.Diagnostics;
 using Xtensive.Collections;
 
diff --git a/Orm/Xtensive.Orm/Orm/Model/ColumnIndexMap.cs b/Orm/Xtensive.Orm/Orm/Model/ColumnIndexMap.cs
index 9e49ed67c..790ea6c6b 100644
--- a/Orm/Xtensive.Orm/Orm/Model/ColumnIndexMap.cs
+++ b/Orm/Xtensive.Orm/Orm/Model/ColumnIndexMap.cs
@@ -4,8 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2009.09.04
 
-using System;
-using System.Collections.Generic;
 
 
 namespace Xtensive.Orm.Model
diff --git a/Orm/Xtensive.Orm/Orm/Model/ColumnInfo.cs b/Orm/Xtensive.Orm/Orm/Model/ColumnInfo.cs
index b6fe08f6f..490d5913b 100644
--- a/Orm/Xtensive.Orm/Orm/Model/ColumnInfo.cs
+++ b/Orm/Xtensive.Orm/Orm/Model/ColumnInfo.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2007.07.06
 
-using System;
 using System.Diagnostics;
 using System.Globalization;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Orm/Model/ColumnInfoCollection.cs b/Orm/Xtensive.Orm/Orm/Model/ColumnInfoCollection.cs
index 3666c2eba..00e7a0726 100644
--- a/Orm/Xtensive.Orm/Orm/Model/ColumnInfoCollection.cs
+++ b/Orm/Xtensive.Orm/Orm/Model/ColumnInfoCollection.cs
@@ -4,9 +4,6 @@
 // Created by: Alexey Kochetov
 // Created:    2007.12.10
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Collections;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Orm/Model/ColumnInfoRef.cs b/Orm/Xtensive.Orm/Orm/Model/ColumnInfoRef.cs
index 5e5c1856c..28d7ecbdb 100644
--- a/Orm/Xtensive.Orm/Orm/Model/ColumnInfoRef.cs
+++ b/Orm/Xtensive.Orm/Orm/Model/ColumnInfoRef.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kochetov
 // Created:    2007.09.21
 
-using System;
 using System.Diagnostics;
 using System.Globalization;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Orm/Model/DatabaseInfo.cs b/Orm/Xtensive.Orm/Orm/Model/DatabaseInfo.cs
index c10e000be..d2880f7f7 100644
--- a/Orm/Xtensive.Orm/Orm/Model/DatabaseInfo.cs
+++ b/Orm/Xtensive.Orm/Orm/Model/DatabaseInfo.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.03.22
 
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Orm.Configuration;
 
 namespace Xtensive.Orm.Model
diff --git a/Orm/Xtensive.Orm/Orm/Model/DomainModel.cs b/Orm/Xtensive.Orm/Orm/Model/DomainModel.cs
index 763a54eae..98b4506fc 100644
--- a/Orm/Xtensive.Orm/Orm/Model/DomainModel.cs
+++ b/Orm/Xtensive.Orm/Orm/Model/DomainModel.cs
@@ -4,9 +4,6 @@
 // Created by: Alex Ustinov
 // Created:    2007.07.11
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Linq.Expressions;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Orm/Model/DomainModelExtensions.cs b/Orm/Xtensive.Orm/Orm/Model/DomainModelExtensions.cs
index 27d267c3a..0fe076263 100644
--- a/Orm/Xtensive.Orm/Orm/Model/DomainModelExtensions.cs
+++ b/Orm/Xtensive.Orm/Orm/Model/DomainModelExtensions.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.05.24
 
-using System;
-using System.Collections.Generic;
 using Xtensive.Core;
 using Xtensive.Sorting;
 using Xtensive.Orm.Model.Stored;
diff --git a/Orm/Xtensive.Orm/Orm/Model/FieldAttributes.cs b/Orm/Xtensive.Orm/Orm/Model/FieldAttributes.cs
index 945187c17..fa2eed329 100644
--- a/Orm/Xtensive.Orm/Orm/Model/FieldAttributes.cs
+++ b/Orm/Xtensive.Orm/Orm/Model/FieldAttributes.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2007.09.29
 
-using System;
 
 namespace Xtensive.Orm.Model
 {
diff --git a/Orm/Xtensive.Orm/Orm/Model/FieldInfo.cs b/Orm/Xtensive.Orm/Orm/Model/FieldInfo.cs
index c7def21ad..567c38b03 100644
--- a/Orm/Xtensive.Orm/Orm/Model/FieldInfo.cs
+++ b/Orm/Xtensive.Orm/Orm/Model/FieldInfo.cs
@@ -4,10 +4,7 @@
 // Created by: Dmitri Maximov
 // Created:    2007.09.10
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
-using System.Linq;
 using System.Diagnostics;
 using System.Reflection;
 using Xtensive.Collections;
diff --git a/Orm/Xtensive.Orm/Orm/Model/FieldInfoCollection.cs b/Orm/Xtensive.Orm/Orm/Model/FieldInfoCollection.cs
index 70e20bc35..18019cd53 100644
--- a/Orm/Xtensive.Orm/Orm/Model/FieldInfoCollection.cs
+++ b/Orm/Xtensive.Orm/Orm/Model/FieldInfoCollection.cs
@@ -4,9 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2007.11.26
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Collections;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Orm/Model/FieldInfoRef.cs b/Orm/Xtensive.Orm/Orm/Model/FieldInfoRef.cs
index 77f654181..4e78b4e8d 100644
--- a/Orm/Xtensive.Orm/Orm/Model/FieldInfoRef.cs
+++ b/Orm/Xtensive.Orm/Orm/Model/FieldInfoRef.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kochetov
 // Created:    2008.07.22
 
-using System;
 using System.Diagnostics;
 
 
diff --git a/Orm/Xtensive.Orm/Orm/Model/FieldMap.cs b/Orm/Xtensive.Orm/Orm/Model/FieldMap.cs
index 3ee5f37c6..505b75122 100644
--- a/Orm/Xtensive.Orm/Orm/Model/FieldMap.cs
+++ b/Orm/Xtensive.Orm/Orm/Model/FieldMap.cs
@@ -4,10 +4,7 @@
 // Created by: Alexey Kochetov
 // Created:    2007.12.27
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Core;
 
 namespace Xtensive.Orm.Model
diff --git a/Orm/Xtensive.Orm/Orm/Model/FullTextColumnInfo.cs b/Orm/Xtensive.Orm/Orm/Model/FullTextColumnInfo.cs
index 5331780d3..f00148bcb 100644
--- a/Orm/Xtensive.Orm/Orm/Model/FullTextColumnInfo.cs
+++ b/Orm/Xtensive.Orm/Orm/Model/FullTextColumnInfo.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2010.01.18
 
-using System;
 using System.Diagnostics;
 
 
diff --git a/Orm/Xtensive.Orm/Orm/Model/FullTextColumnInfoCollection.cs b/Orm/Xtensive.Orm/Orm/Model/FullTextColumnInfoCollection.cs
index c0fcdc2f7..01c101a27 100644
--- a/Orm/Xtensive.Orm/Orm/Model/FullTextColumnInfoCollection.cs
+++ b/Orm/Xtensive.Orm/Orm/Model/FullTextColumnInfoCollection.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2010.01.18
 
-using System;
 using System.Diagnostics;
 
 namespace Xtensive.Orm.Model
diff --git a/Orm/Xtensive.Orm/Orm/Model/FullTextIndexInfo.cs b/Orm/Xtensive.Orm/Orm/Model/FullTextIndexInfo.cs
index 0d043571b..c837a66c5 100644
--- a/Orm/Xtensive.Orm/Orm/Model/FullTextIndexInfo.cs
+++ b/Orm/Xtensive.Orm/Orm/Model/FullTextIndexInfo.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.12.23
 
-using System;
 
 
 namespace Xtensive.Orm.Model
diff --git a/Orm/Xtensive.Orm/Orm/Model/FullTextIndexInfoCollection.cs b/Orm/Xtensive.Orm/Orm/Model/FullTextIndexInfoCollection.cs
index c2c389493..10e1a948a 100644
--- a/Orm/Xtensive.Orm/Orm/Model/FullTextIndexInfoCollection.cs
+++ b/Orm/Xtensive.Orm/Orm/Model/FullTextIndexInfoCollection.cs
@@ -4,10 +4,7 @@
 // Created by: Alexis Kochetov
 // Created:    2009.12.23
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Core;
 
 namespace Xtensive.Orm.Model
diff --git a/Orm/Xtensive.Orm/Orm/Model/HierarchyInfo.cs b/Orm/Xtensive.Orm/Orm/Model/HierarchyInfo.cs
index 7ced94137..9cee87ae7 100644
--- a/Orm/Xtensive.Orm/Orm/Model/HierarchyInfo.cs
+++ b/Orm/Xtensive.Orm/Orm/Model/HierarchyInfo.cs
@@ -4,8 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2008.01.11
 
-using System;
-using System.Collections.Generic;
 
 namespace Xtensive.Orm.Model
 {
diff --git a/Orm/Xtensive.Orm/Orm/Model/HierarchyInfoCollection.cs b/Orm/Xtensive.Orm/Orm/Model/HierarchyInfoCollection.cs
index fe661448a..6ce02daa9 100644
--- a/Orm/Xtensive.Orm/Orm/Model/HierarchyInfoCollection.cs
+++ b/Orm/Xtensive.Orm/Orm/Model/HierarchyInfoCollection.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2008.01.11
 
-using System;
 
 
 namespace Xtensive.Orm.Model
diff --git a/Orm/Xtensive.Orm/Orm/Model/IndexAttributes.cs b/Orm/Xtensive.Orm/Orm/Model/IndexAttributes.cs
index d2542954c..186ba1f31 100644
--- a/Orm/Xtensive.Orm/Orm/Model/IndexAttributes.cs
+++ b/Orm/Xtensive.Orm/Orm/Model/IndexAttributes.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2007.07.23
 
-using System;
 
 namespace Xtensive.Orm.Model
 {
diff --git a/Orm/Xtensive.Orm/Orm/Model/IndexInfo.cs b/Orm/Xtensive.Orm/Orm/Model/IndexInfo.cs
index 569873d97..9716bbde5 100644
--- a/Orm/Xtensive.Orm/Orm/Model/IndexInfo.cs
+++ b/Orm/Xtensive.Orm/Orm/Model/IndexInfo.cs
@@ -4,11 +4,8 @@
 // Created by: Alex Ustinov
 // Created:    2007.07.10
 
-using System;
-using System.Collections.Generic;
 using System.Collections.ObjectModel;
 using System.Diagnostics;
-using System.Linq;
 using System.Linq.Expressions;
 using Xtensive.Collections;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Orm/Model/IndexInfoCollection.cs b/Orm/Xtensive.Orm/Orm/Model/IndexInfoCollection.cs
index a5988b8ec..ffb2c8b20 100644
--- a/Orm/Xtensive.Orm/Orm/Model/IndexInfoCollection.cs
+++ b/Orm/Xtensive.Orm/Orm/Model/IndexInfoCollection.cs
@@ -4,9 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2008.05.16
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Collections;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Orm/Model/IndexInfoRef.cs b/Orm/Xtensive.Orm/Orm/Model/IndexInfoRef.cs
index 12ad5cd53..e5af3281c 100644
--- a/Orm/Xtensive.Orm/Orm/Model/IndexInfoRef.cs
+++ b/Orm/Xtensive.Orm/Orm/Model/IndexInfoRef.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kochetov
 // Created:    2008.07.22
 
-using System;
 using System.Diagnostics;
 
 using Xtensive.Tuples;
diff --git a/Orm/Xtensive.Orm/Orm/Model/Internals/TypePairComparer.cs b/Orm/Xtensive.Orm/Orm/Model/Internals/TypePairComparer.cs
index 1dad31984..361a8a528 100644
--- a/Orm/Xtensive.Orm/Orm/Model/Internals/TypePairComparer.cs
+++ b/Orm/Xtensive.Orm/Orm/Model/Internals/TypePairComparer.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2008.03.17
 
-using System.Collections.Generic;
 using Xtensive.Comparison;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Orm/Model/KeyField.cs b/Orm/Xtensive.Orm/Orm/Model/KeyField.cs
index 1856846ce..b03727ee0 100644
--- a/Orm/Xtensive.Orm/Orm/Model/KeyField.cs
+++ b/Orm/Xtensive.Orm/Orm/Model/KeyField.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2007.12.28
 
-using System;
 using Xtensive.Core;
 
 
diff --git a/Orm/Xtensive.Orm/Orm/Model/KeyInfo.cs b/Orm/Xtensive.Orm/Orm/Model/KeyInfo.cs
index a3ef2a6fa..d3245a934 100644
--- a/Orm/Xtensive.Orm/Orm/Model/KeyInfo.cs
+++ b/Orm/Xtensive.Orm/Orm/Model/KeyInfo.cs
@@ -4,10 +4,7 @@
 // Created by: Dmitri Maximov
 // Created:    2009.02.13
 
-using System;
-using System.Collections.Generic;
 using System.Collections.ObjectModel;
-using System.Linq;
 using Xtensive.Collections;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Orm/Model/MappedNode.cs b/Orm/Xtensive.Orm/Orm/Model/MappedNode.cs
index a3a75ddf5..41f16af2f 100644
--- a/Orm/Xtensive.Orm/Orm/Model/MappedNode.cs
+++ b/Orm/Xtensive.Orm/Orm/Model/MappedNode.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2008.01.13
 
-using System;
 using Xtensive.Core;
 
 namespace Xtensive.Orm.Model
diff --git a/Orm/Xtensive.Orm/Orm/Model/ModelVisitor.cs b/Orm/Xtensive.Orm/Orm/Model/ModelVisitor.cs
index 71ecc7ded..8f178f3db 100644
--- a/Orm/Xtensive.Orm/Orm/Model/ModelVisitor.cs
+++ b/Orm/Xtensive.Orm/Orm/Model/ModelVisitor.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.04.02
 
-using System;
 
 
 namespace Xtensive.Orm.Model
diff --git a/Orm/Xtensive.Orm/Orm/Model/Node.cs b/Orm/Xtensive.Orm/Orm/Model/Node.cs
index 5dd5521a6..fb2a950a3 100644
--- a/Orm/Xtensive.Orm/Orm/Model/Node.cs
+++ b/Orm/Xtensive.Orm/Orm/Model/Node.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2007.07.25
 
-using System;
 using Xtensive.Collections;
 using Xtensive.Core;
 using Xtensive.Reflection;
diff --git a/Orm/Xtensive.Orm/Orm/Model/NodeCollection.cs b/Orm/Xtensive.Orm/Orm/Model/NodeCollection.cs
index 687dda668..8742a1830 100644
--- a/Orm/Xtensive.Orm/Orm/Model/NodeCollection.cs
+++ b/Orm/Xtensive.Orm/Orm/Model/NodeCollection.cs
@@ -4,8 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2007.07.30
 
-using System;
-using System.Collections.Generic;
 using System.Diagnostics;
 using Xtensive.Collections;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Orm/Model/OnRemoveAction.cs b/Orm/Xtensive.Orm/Orm/Model/OnRemoveAction.cs
index 0dcdf8fec..80f7c63fc 100644
--- a/Orm/Xtensive.Orm/Orm/Model/OnRemoveAction.cs
+++ b/Orm/Xtensive.Orm/Orm/Model/OnRemoveAction.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2008.06.24
 
-using System;
 
 namespace Xtensive.Orm
 {
diff --git a/Orm/Xtensive.Orm/Orm/Model/PartialIndexFilterInfo.cs b/Orm/Xtensive.Orm/Orm/Model/PartialIndexFilterInfo.cs
index 8de3e95f0..72b8b8c49 100644
--- a/Orm/Xtensive.Orm/Orm/Model/PartialIndexFilterInfo.cs
+++ b/Orm/Xtensive.Orm/Orm/Model/PartialIndexFilterInfo.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2011.10.10
 
-using System.Collections.Generic;
-using System.Linq;
 using System.Linq.Expressions;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Orm/Model/SchemaMappedNode.cs b/Orm/Xtensive.Orm/Orm/Model/SchemaMappedNode.cs
index dd4424799..cf4fdc874 100644
--- a/Orm/Xtensive.Orm/Orm/Model/SchemaMappedNode.cs
+++ b/Orm/Xtensive.Orm/Orm/Model/SchemaMappedNode.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.02.10
 
-using System;
 using Xtensive.Core;
 
 namespace Xtensive.Orm.Model
diff --git a/Orm/Xtensive.Orm/Orm/Model/SequenceInfo.cs b/Orm/Xtensive.Orm/Orm/Model/SequenceInfo.cs
index 5ac313f09..7f6f5c210 100644
--- a/Orm/Xtensive.Orm/Orm/Model/SequenceInfo.cs
+++ b/Orm/Xtensive.Orm/Orm/Model/SequenceInfo.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2010.02.09
 
-using System;
 using System.Diagnostics;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Orm/Model/Stored/Internals/ConverterToStoredModel.cs b/Orm/Xtensive.Orm/Orm/Model/Stored/Internals/ConverterToStoredModel.cs
index 3f60975d4..9dffb9ef1 100644
--- a/Orm/Xtensive.Orm/Orm/Model/Stored/Internals/ConverterToStoredModel.cs
+++ b/Orm/Xtensive.Orm/Orm/Model/Stored/Internals/ConverterToStoredModel.cs
@@ -4,9 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.05.24
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Reflection;
 
 namespace Xtensive.Orm.Model.Stored
diff --git a/Orm/Xtensive.Orm/Orm/Model/Stored/Internals/ReferenceUpdater.cs b/Orm/Xtensive.Orm/Orm/Model/Stored/Internals/ReferenceUpdater.cs
index c93537c17..cf58515a6 100644
--- a/Orm/Xtensive.Orm/Orm/Model/Stored/Internals/ReferenceUpdater.cs
+++ b/Orm/Xtensive.Orm/Orm/Model/Stored/Internals/ReferenceUpdater.cs
@@ -4,9 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.05.22
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Collections;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Orm/Model/Stored/StoredAssociationInfo.cs b/Orm/Xtensive.Orm/Orm/Model/Stored/StoredAssociationInfo.cs
index 27362e76a..d72547185 100644
--- a/Orm/Xtensive.Orm/Orm/Model/Stored/StoredAssociationInfo.cs
+++ b/Orm/Xtensive.Orm/Orm/Model/Stored/StoredAssociationInfo.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.05.22
 
-using System;
 using System.ComponentModel;
 using System.Xml.Serialization;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Orm/Model/Stored/StoredFieldInfo.cs b/Orm/Xtensive.Orm/Orm/Model/Stored/StoredFieldInfo.cs
index 3a9e7cc95..31a9b61e8 100644
--- a/Orm/Xtensive.Orm/Orm/Model/Stored/StoredFieldInfo.cs
+++ b/Orm/Xtensive.Orm/Orm/Model/Stored/StoredFieldInfo.cs
@@ -4,11 +4,8 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.05.22
 
-using System.Collections.Generic;
 using System.ComponentModel;
-using System.Linq;
 using System.Xml.Serialization;
-using System;
 using Xtensive.Collections;
 
 namespace Xtensive.Orm.Model.Stored
diff --git a/Orm/Xtensive.Orm/Orm/Model/Stored/StoredTypeInfo.cs b/Orm/Xtensive.Orm/Orm/Model/Stored/StoredTypeInfo.cs
index b8ba8fa3e..4205b43ad 100644
--- a/Orm/Xtensive.Orm/Orm/Model/Stored/StoredTypeInfo.cs
+++ b/Orm/Xtensive.Orm/Orm/Model/Stored/StoredTypeInfo.cs
@@ -4,10 +4,8 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.05.22
 
-using System;
 using System.ComponentModel;
 using System.Diagnostics;
-using System.Linq;
 using System.Xml.Serialization;
 
 namespace Xtensive.Orm.Model.Stored
diff --git a/Orm/Xtensive.Orm/Orm/Model/TypeAttributes.cs b/Orm/Xtensive.Orm/Orm/Model/TypeAttributes.cs
index 0335e53d1..bc25dd50b 100644
--- a/Orm/Xtensive.Orm/Orm/Model/TypeAttributes.cs
+++ b/Orm/Xtensive.Orm/Orm/Model/TypeAttributes.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitry Maximov
 // Created:    2007.09.29
 
-using System;
 
 namespace Xtensive.Orm.Model
 {
diff --git a/Orm/Xtensive.Orm/Orm/Model/TypeDiscriminatorMap.cs b/Orm/Xtensive.Orm/Orm/Model/TypeDiscriminatorMap.cs
index c789a1425..3c8d9d536 100644
--- a/Orm/Xtensive.Orm/Orm/Model/TypeDiscriminatorMap.cs
+++ b/Orm/Xtensive.Orm/Orm/Model/TypeDiscriminatorMap.cs
@@ -4,11 +4,8 @@
 // Created by: Dmitri Maximov
 // Created:    2009.11.26
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
 using Xtensive.Core;
-using System.Linq;
 
 namespace Xtensive.Orm.Model
 {
diff --git a/Orm/Xtensive.Orm/Orm/Model/TypeIdRegistry.cs b/Orm/Xtensive.Orm/Orm/Model/TypeIdRegistry.cs
index 88eced72c..ce72e5b84 100644
--- a/Orm/Xtensive.Orm/Orm/Model/TypeIdRegistry.cs
+++ b/Orm/Xtensive.Orm/Orm/Model/TypeIdRegistry.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2014.03.13
 
-using System;
-using System.Collections.Generic;
 using Xtensive.Core;
 
 namespace Xtensive.Orm.Model
diff --git a/Orm/Xtensive.Orm/Orm/Model/TypeIndexInfoCollection.cs b/Orm/Xtensive.Orm/Orm/Model/TypeIndexInfoCollection.cs
index 2911d4b34..1b7d7f54e 100644
--- a/Orm/Xtensive.Orm/Orm/Model/TypeIndexInfoCollection.cs
+++ b/Orm/Xtensive.Orm/Orm/Model/TypeIndexInfoCollection.cs
@@ -4,10 +4,7 @@
 // Created by: Alexey Kochetov
 // Created:    2007.11.26
 
-using System;
 using System.Diagnostics;
-using System.Linq;
-using System.Collections.Generic;
 
 namespace Xtensive.Orm.Model
 {
diff --git a/Orm/Xtensive.Orm/Orm/Model/TypeInfo.cs b/Orm/Xtensive.Orm/Orm/Model/TypeInfo.cs
index e98d4150e..1b7f5bf0b 100644
--- a/Orm/Xtensive.Orm/Orm/Model/TypeInfo.cs
+++ b/Orm/Xtensive.Orm/Orm/Model/TypeInfo.cs
@@ -4,13 +4,10 @@
 // Created by: Dmitri Maximov
 // Created:    2007.08.27
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
 using System.Collections.Immutable;
 using System.Collections.ObjectModel;
 using System.Diagnostics;
-using System.Linq;
 using JetBrains.Annotations;
 using Xtensive.Core;
 using Xtensive.Orm.Internals;
diff --git a/Orm/Xtensive.Orm/Orm/Model/TypeInfoCollection.cs b/Orm/Xtensive.Orm/Orm/Model/TypeInfoCollection.cs
index 00105cbb1..d2a69ef40 100644
--- a/Orm/Xtensive.Orm/Orm/Model/TypeInfoCollection.cs
+++ b/Orm/Xtensive.Orm/Orm/Model/TypeInfoCollection.cs
@@ -4,9 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2007.08.27
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Collections;
 using Xtensive.Core;
 using Xtensive.Reflection;
diff --git a/Orm/Xtensive.Orm/Orm/Model/TypeInfoRef.cs b/Orm/Xtensive.Orm/Orm/Model/TypeInfoRef.cs
index 5e243b8b3..dda00533b 100644
--- a/Orm/Xtensive.Orm/Orm/Model/TypeInfoRef.cs
+++ b/Orm/Xtensive.Orm/Orm/Model/TypeInfoRef.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kochetov
 // Created:    2008.07.22
 
-using System;
 using System.Diagnostics;
 
 
diff --git a/Orm/Xtensive.Orm/Orm/NotifyChangedOptions.cs b/Orm/Xtensive.Orm/Orm/NotifyChangedOptions.cs
index 0baf66b9e..2ab63d023 100644
--- a/Orm/Xtensive.Orm/Orm/NotifyChangedOptions.cs
+++ b/Orm/Xtensive.Orm/Orm/NotifyChangedOptions.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2010.08.03
 
-using System;
 using System.Diagnostics;
 
 namespace Xtensive.Orm
diff --git a/Orm/Xtensive.Orm/Orm/Operation.cs b/Orm/Xtensive.Orm/Orm/Operation.cs
index 3ff190b0f..3baa0fdf7 100644
--- a/Orm/Xtensive.Orm/Orm/Operation.cs
+++ b/Orm/Xtensive.Orm/Orm/Operation.cs
@@ -4,11 +4,8 @@
 // Created by: Alexis Kochetov
 // Created:    2009.11.19
 
-using System;
-using System.Collections.Generic;
 using System.Collections.ObjectModel;
 using System.Diagnostics;
-using System.Linq;
 using Xtensive.Core;
 
 using Xtensive.Orm.Operations;
diff --git a/Orm/Xtensive.Orm/Orm/OperationLog.cs b/Orm/Xtensive.Orm/Orm/OperationLog.cs
index 333a83a43..2adfb7b78 100644
--- a/Orm/Xtensive.Orm/Orm/OperationLog.cs
+++ b/Orm/Xtensive.Orm/Orm/OperationLog.cs
@@ -4,9 +4,7 @@
 // Created by: Alexis Kochetov
 // Created:    2009.10.22
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
 using System.Text;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Orm/OperationLogType.cs b/Orm/Xtensive.Orm/Orm/OperationLogType.cs
index 57f2811d4..dcdd55b9f 100644
--- a/Orm/Xtensive.Orm/Orm/OperationLogType.cs
+++ b/Orm/Xtensive.Orm/Orm/OperationLogType.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2010.08.05
 
-using System;
 using System.Diagnostics;
 
 namespace Xtensive.Orm
diff --git a/Orm/Xtensive.Orm/Orm/Operations/EntitiesRemoveOperation.cs b/Orm/Xtensive.Orm/Orm/Operations/EntitiesRemoveOperation.cs
index 1f378137c..383b68f58 100644
--- a/Orm/Xtensive.Orm/Orm/Operations/EntitiesRemoveOperation.cs
+++ b/Orm/Xtensive.Orm/Orm/Operations/EntitiesRemoveOperation.cs
@@ -4,10 +4,7 @@
 // Created by: Alex Yakunin
 // Created:    2010.02.25
 
-using System;
-using System.Collections.Generic;
 using System.Diagnostics;
-using System.Linq;
 using System.Runtime.Serialization;
 using System.Security;
 using System.Security.Permissions;
diff --git a/Orm/Xtensive.Orm/Orm/Operations/EntityCreateOperation.cs b/Orm/Xtensive.Orm/Orm/Operations/EntityCreateOperation.cs
index f65c759a2..c5a5df333 100644
--- a/Orm/Xtensive.Orm/Orm/Operations/EntityCreateOperation.cs
+++ b/Orm/Xtensive.Orm/Orm/Operations/EntityCreateOperation.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2010.02.25
 
-using System;
 using System.Runtime.Serialization;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Orm/Operations/EntityFieldOperation.cs b/Orm/Xtensive.Orm/Orm/Operations/EntityFieldOperation.cs
index 9b1c67dca..7eb2fd2bf 100644
--- a/Orm/Xtensive.Orm/Orm/Operations/EntityFieldOperation.cs
+++ b/Orm/Xtensive.Orm/Orm/Operations/EntityFieldOperation.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.11.19
 
-using System;
 using System.Runtime.Serialization;
 using System.Security;
 using System.Security.Permissions;
diff --git a/Orm/Xtensive.Orm/Orm/Operations/EntityFieldSetOperation.cs b/Orm/Xtensive.Orm/Orm/Operations/EntityFieldSetOperation.cs
index e8aa99d59..a0349f8b9 100644
--- a/Orm/Xtensive.Orm/Orm/Operations/EntityFieldSetOperation.cs
+++ b/Orm/Xtensive.Orm/Orm/Operations/EntityFieldSetOperation.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.10.22
 
-using System;
 using System.Diagnostics;
 using System.Runtime.Serialization;
 using System.Security;
diff --git a/Orm/Xtensive.Orm/Orm/Operations/EntityIdentifierType.cs b/Orm/Xtensive.Orm/Orm/Operations/EntityIdentifierType.cs
index 99e73d8cd..270e42256 100644
--- a/Orm/Xtensive.Orm/Orm/Operations/EntityIdentifierType.cs
+++ b/Orm/Xtensive.Orm/Orm/Operations/EntityIdentifierType.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2010.07.28
 
-using System;
 using System.Diagnostics;
 
 namespace Xtensive.Orm.Operations
diff --git a/Orm/Xtensive.Orm/Orm/Operations/EntityInitializeOperation.cs b/Orm/Xtensive.Orm/Orm/Operations/EntityInitializeOperation.cs
index 1d15fa973..c615105d9 100644
--- a/Orm/Xtensive.Orm/Orm/Operations/EntityInitializeOperation.cs
+++ b/Orm/Xtensive.Orm/Orm/Operations/EntityInitializeOperation.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2010.08.11
 
-using System;
 using System.Diagnostics;
 using System.Runtime.Serialization;
 
diff --git a/Orm/Xtensive.Orm/Orm/Operations/EntityOperation.cs b/Orm/Xtensive.Orm/Orm/Operations/EntityOperation.cs
index 61437c70c..c0ea48cc2 100644
--- a/Orm/Xtensive.Orm/Orm/Operations/EntityOperation.cs
+++ b/Orm/Xtensive.Orm/Orm/Operations/EntityOperation.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.10.22
 
-using System;
 using System.Runtime.Serialization;
 using System.Security.Permissions;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Orm/Operations/EntitySetClearOperation.cs b/Orm/Xtensive.Orm/Orm/Operations/EntitySetClearOperation.cs
index 57f586d3a..6da464a92 100644
--- a/Orm/Xtensive.Orm/Orm/Operations/EntitySetClearOperation.cs
+++ b/Orm/Xtensive.Orm/Orm/Operations/EntitySetClearOperation.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2010.02.25
 
-using System;
 using System.Runtime.Serialization;
 using Xtensive.Orm.Model;
 
diff --git a/Orm/Xtensive.Orm/Orm/Operations/EntitySetItemAddOperation.cs b/Orm/Xtensive.Orm/Orm/Operations/EntitySetItemAddOperation.cs
index 2b2b392a7..f5abc47f1 100644
--- a/Orm/Xtensive.Orm/Orm/Operations/EntitySetItemAddOperation.cs
+++ b/Orm/Xtensive.Orm/Orm/Operations/EntitySetItemAddOperation.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2010.02.25
 
-using System;
 using System.Runtime.Serialization;
 using Xtensive.Orm.Model;
 
diff --git a/Orm/Xtensive.Orm/Orm/Operations/EntitySetItemOperation.cs b/Orm/Xtensive.Orm/Orm/Operations/EntitySetItemOperation.cs
index 3840c3e46..7bf4b445d 100644
--- a/Orm/Xtensive.Orm/Orm/Operations/EntitySetItemOperation.cs
+++ b/Orm/Xtensive.Orm/Orm/Operations/EntitySetItemOperation.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.10.22
 
-using System;
 using System.Runtime.Serialization;
 using System.Security;
 using System.Security.Permissions;
diff --git a/Orm/Xtensive.Orm/Orm/Operations/EntitySetItemRemoveOperation.cs b/Orm/Xtensive.Orm/Orm/Operations/EntitySetItemRemoveOperation.cs
index 6b905898f..013acfc23 100644
--- a/Orm/Xtensive.Orm/Orm/Operations/EntitySetItemRemoveOperation.cs
+++ b/Orm/Xtensive.Orm/Orm/Operations/EntitySetItemRemoveOperation.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2010.02.25
 
-using System;
 using System.Runtime.Serialization;
 using Xtensive.Orm.Model;
 
diff --git a/Orm/Xtensive.Orm/Orm/Operations/EntitySetOperation.cs b/Orm/Xtensive.Orm/Orm/Operations/EntitySetOperation.cs
index 0cebe22e4..80c0012d8 100644
--- a/Orm/Xtensive.Orm/Orm/Operations/EntitySetOperation.cs
+++ b/Orm/Xtensive.Orm/Orm/Operations/EntitySetOperation.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.11.20
 
-using System;
 using System.Runtime.Serialization;
 using Xtensive.Orm.Internals;
 using Xtensive.Orm.Model;
diff --git a/Orm/Xtensive.Orm/Orm/Operations/Internals/OperationRegistrationScope.cs b/Orm/Xtensive.Orm/Orm/Operations/Internals/OperationRegistrationScope.cs
index 9b788a7b3..d9b3909b7 100644
--- a/Orm/Xtensive.Orm/Orm/Operations/Internals/OperationRegistrationScope.cs
+++ b/Orm/Xtensive.Orm/Orm/Operations/Internals/OperationRegistrationScope.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2010.08.04
 
-using System;
-using System.Collections.Generic;
 using Xtensive.Core;
 
 
diff --git a/Orm/Xtensive.Orm/Orm/Operations/KeyGenerateOperation.cs b/Orm/Xtensive.Orm/Orm/Operations/KeyGenerateOperation.cs
index cbc3852cc..4f6d0e131 100644
--- a/Orm/Xtensive.Orm/Orm/Operations/KeyGenerateOperation.cs
+++ b/Orm/Xtensive.Orm/Orm/Operations/KeyGenerateOperation.cs
@@ -4,8 +4,6 @@
 // Created by: Alexander Nikolaev
 // Created:    2010.02.15
 
-using System;
-using System.Linq;
 using System.Runtime.Serialization;
 using Xtensive.Core;
 using Xtensive.Tuples;
diff --git a/Orm/Xtensive.Orm/Orm/Operations/KeyOperation.cs b/Orm/Xtensive.Orm/Orm/Operations/KeyOperation.cs
index 521f7c72f..0dc07568b 100644
--- a/Orm/Xtensive.Orm/Orm/Operations/KeyOperation.cs
+++ b/Orm/Xtensive.Orm/Orm/Operations/KeyOperation.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.10.22
 
-using System;
 using System.Runtime.Serialization;
 using System.Security;
 using System.Security.Permissions;
diff --git a/Orm/Xtensive.Orm/Orm/Operations/KeySetOperation.cs b/Orm/Xtensive.Orm/Orm/Operations/KeySetOperation.cs
index 99bae45c0..20db5dd16 100644
--- a/Orm/Xtensive.Orm/Orm/Operations/KeySetOperation.cs
+++ b/Orm/Xtensive.Orm/Orm/Operations/KeySetOperation.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2010.08.10
 
-using System;
-using System.Collections.Generic;
 using System.Diagnostics;
 using System.Runtime.Serialization;
 using System.Security;
@@ -13,7 +11,6 @@
 using Xtensive.Core;
 using Xtensive.Collections;
 
-using System.Linq;
 
 namespace Xtensive.Orm.Operations
 {
diff --git a/Orm/Xtensive.Orm/Orm/Operations/MethodCallOperation.cs b/Orm/Xtensive.Orm/Orm/Operations/MethodCallOperation.cs
index 629f2632e..ccc5cd4be 100644
--- a/Orm/Xtensive.Orm/Orm/Operations/MethodCallOperation.cs
+++ b/Orm/Xtensive.Orm/Orm/Operations/MethodCallOperation.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.11.23
 
-using System;
 using Xtensive.Core;
 
 using Xtensive.Reflection;
diff --git a/Orm/Xtensive.Orm/Orm/Operations/OperationCapturer.cs b/Orm/Xtensive.Orm/Orm/Operations/OperationCapturer.cs
index b76bbd4f1..4a513b05a 100644
--- a/Orm/Xtensive.Orm/Orm/Operations/OperationCapturer.cs
+++ b/Orm/Xtensive.Orm/Orm/Operations/OperationCapturer.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.10.22
 
-using System;
 using Xtensive.Core;
 
 namespace Xtensive.Orm.Operations
diff --git a/Orm/Xtensive.Orm/Orm/Operations/OperationCompletedEventArgs.cs b/Orm/Xtensive.Orm/Orm/Operations/OperationCompletedEventArgs.cs
index 1934192ef..e27713ee2 100644
--- a/Orm/Xtensive.Orm/Orm/Operations/OperationCompletedEventArgs.cs
+++ b/Orm/Xtensive.Orm/Orm/Operations/OperationCompletedEventArgs.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2010.08.04
 
-using System;
 using System.Diagnostics;
 
 
diff --git a/Orm/Xtensive.Orm/Orm/Operations/OperationEventArgs.cs b/Orm/Xtensive.Orm/Orm/Operations/OperationEventArgs.cs
index 016586ea6..7b877d697 100644
--- a/Orm/Xtensive.Orm/Orm/Operations/OperationEventArgs.cs
+++ b/Orm/Xtensive.Orm/Orm/Operations/OperationEventArgs.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.11.23
 
-using System;
 using System.Diagnostics;
 
 
diff --git a/Orm/Xtensive.Orm/Orm/Operations/OperationExecutionContext.cs b/Orm/Xtensive.Orm/Orm/Operations/OperationExecutionContext.cs
index 7ed4bd4b4..cc83e974e 100644
--- a/Orm/Xtensive.Orm/Orm/Operations/OperationExecutionContext.cs
+++ b/Orm/Xtensive.Orm/Orm/Operations/OperationExecutionContext.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.10.21
 
-using System.Collections.Generic;
 using System.Collections.ObjectModel;
 
 
diff --git a/Orm/Xtensive.Orm/Orm/Operations/OperationRegistry.cs b/Orm/Xtensive.Orm/Orm/Operations/OperationRegistry.cs
index cc4e6b4d0..c52b7f539 100644
--- a/Orm/Xtensive.Orm/Orm/Operations/OperationRegistry.cs
+++ b/Orm/Xtensive.Orm/Orm/Operations/OperationRegistry.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2010.08.04
 
-using System;
-using System.Collections.Generic;
 using System.Collections.ObjectModel;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Orm/Operations/OperationType.cs b/Orm/Xtensive.Orm/Orm/Operations/OperationType.cs
index c1d10ea3a..9f47d8597 100644
--- a/Orm/Xtensive.Orm/Orm/Operations/OperationType.cs
+++ b/Orm/Xtensive.Orm/Orm/Operations/OperationType.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2010.08.04
 
-using System;
 using System.Diagnostics;
 
 namespace Xtensive.Orm.Operations
diff --git a/Orm/Xtensive.Orm/Orm/Operations/ValidateVersionOperation.cs b/Orm/Xtensive.Orm/Orm/Operations/ValidateVersionOperation.cs
index b0244467c..69d162059 100644
--- a/Orm/Xtensive.Orm/Orm/Operations/ValidateVersionOperation.cs
+++ b/Orm/Xtensive.Orm/Orm/Operations/ValidateVersionOperation.cs
@@ -4,7 +4,6 @@
 // Created by: Alexander Nikolaev
 // Created:    2010.02.19
 
-using System;
 using System.Runtime.Serialization;
 using System.Security;
 using System.Security.Permissions;
diff --git a/Orm/Xtensive.Orm/Orm/Persistent.cs b/Orm/Xtensive.Orm/Orm/Persistent.cs
index 3e48bca07..d5855feb5 100644
--- a/Orm/Xtensive.Orm/Orm/Persistent.cs
+++ b/Orm/Xtensive.Orm/Orm/Persistent.cs
@@ -4,10 +4,7 @@
 // Created by: Dmitri Maximov
 // Created:    2007.08.03
 
-using System;
-using System.Collections.Generic;
 using System.ComponentModel;
-using System.Linq;
 using System.Reflection;
 using Xtensive.Core;
 using Xtensive.Orm.Internals;
diff --git a/Orm/Xtensive.Orm/Orm/PersistentFieldState.cs b/Orm/Xtensive.Orm/Orm/PersistentFieldState.cs
index df39dca52..defa6261a 100644
--- a/Orm/Xtensive.Orm/Orm/PersistentFieldState.cs
+++ b/Orm/Xtensive.Orm/Orm/PersistentFieldState.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2009.12.18
 
-using System;
 
 namespace Xtensive.Orm
 {
diff --git a/Orm/Xtensive.Orm/Orm/PrefetchExtensions.cs b/Orm/Xtensive.Orm/Orm/PrefetchExtensions.cs
index ae54d5616..1005ab922 100644
--- a/Orm/Xtensive.Orm/Orm/PrefetchExtensions.cs
+++ b/Orm/Xtensive.Orm/Orm/PrefetchExtensions.cs
@@ -4,9 +4,6 @@
 // Created by: Alexander Nikolaev
 // Created:    2009.09.30
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Linq.Expressions;
 using Xtensive.Orm.Internals.Prefetch;
 using Xtensive.Orm.Linq;
diff --git a/Orm/Xtensive.Orm/Orm/PrefetchQuery.cs b/Orm/Xtensive.Orm/Orm/PrefetchQuery.cs
index c3c25ec4d..841f465a3 100644
--- a/Orm/Xtensive.Orm/Orm/PrefetchQuery.cs
+++ b/Orm/Xtensive.Orm/Orm/PrefetchQuery.cs
@@ -2,12 +2,8 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
 using System.Linq.Expressions;
-using System.Threading;
-using System.Threading.Tasks;
 using Xtensive.Collections;
 using Xtensive.Orm.Internals.Prefetch;
 
diff --git a/Orm/Xtensive.Orm/Orm/Providers/ChainingSessionHandler.cs b/Orm/Xtensive.Orm/Orm/Providers/ChainingSessionHandler.cs
index d375f1775..1a6d185f1 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/ChainingSessionHandler.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/ChainingSessionHandler.cs
@@ -4,14 +4,12 @@
 // Created by: Alexander Nikolaev
 // Created:    2009.07.06
 
-using System.Collections.Generic;
-using System.Threading;
-using System.Threading.Tasks;
 using Xtensive.Core;
 using Xtensive.Orm.Internals;
 using Xtensive.Orm.Internals.Prefetch;
 using Xtensive.Orm.Model;
 using Xtensive.Tuples;
+using Tuple = Xtensive.Tuples.Tuple;
 
 namespace Xtensive.Orm.Providers
 {
diff --git a/Orm/Xtensive.Orm/Orm/Providers/CommandProcessing/BatchingCommandProcessor.cs b/Orm/Xtensive.Orm/Orm/Providers/CommandProcessing/BatchingCommandProcessor.cs
index f2bad2309..6420cb4aa 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/CommandProcessing/BatchingCommandProcessor.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/CommandProcessing/BatchingCommandProcessor.cs
@@ -4,10 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.08.20
 
-using System.Collections.Generic;
-using System.Linq;
-using System.Threading;
-using System.Threading.Tasks;
 using Xtensive.Core;
 
 namespace Xtensive.Orm.Providers
diff --git a/Orm/Xtensive.Orm/Orm/Providers/CommandProcessing/Command.cs b/Orm/Xtensive.Orm/Orm/Providers/CommandProcessing/Command.cs
index bfdeb1562..a197b4459 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/CommandProcessing/Command.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/CommandProcessing/Command.cs
@@ -4,11 +4,7 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.10.09
 
-using System;
-using System.Collections.Generic;
 using System.Data.Common;
-using System.Threading;
-using System.Threading.Tasks;
 using Xtensive.Core;
 
 using Tuple = Xtensive.Tuples.Tuple;
diff --git a/Orm/Xtensive.Orm/Orm/Providers/CommandProcessing/CommandFactory.cs b/Orm/Xtensive.Orm/Orm/Providers/CommandProcessing/CommandFactory.cs
index 208a6c89a..00c813586 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/CommandProcessing/CommandFactory.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/CommandProcessing/CommandFactory.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.10.09
 
-using System;
-using System.Collections.Generic;
 using System.Reflection;
 using Xtensive.Core;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm/Orm/Providers/CommandProcessing/CommandPart.cs b/Orm/Xtensive.Orm/Orm/Providers/CommandProcessing/CommandPart.cs
index 301f6b3cc..5d6d89cde 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/CommandProcessing/CommandPart.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/CommandProcessing/CommandPart.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.10.09
 
-using System;
-using System.Collections.Generic;
 using System.Data.Common;
 
 namespace Xtensive.Orm.Providers
diff --git a/Orm/Xtensive.Orm/Orm/Providers/CommandProcessing/CommandProcessor.cs b/Orm/Xtensive.Orm/Orm/Providers/CommandProcessing/CommandProcessor.cs
index 7c2e3a5d6..d36b26074 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/CommandProcessing/CommandProcessor.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/CommandProcessing/CommandProcessor.cs
@@ -4,9 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.08.20
 
-using System.Collections.Generic;
-using System.Threading;
-using System.Threading.Tasks;
 using Xtensive.Core;
 
 namespace Xtensive.Orm.Providers
diff --git a/Orm/Xtensive.Orm/Orm/Providers/CommandProcessing/CommandProcessorContext.cs b/Orm/Xtensive.Orm/Orm/Providers/CommandProcessing/CommandProcessorContext.cs
index 13537473c..df78d8e66 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/CommandProcessing/CommandProcessorContext.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/CommandProcessing/CommandProcessorContext.cs
@@ -4,9 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2019.07.12
 
-using System;
-using System.Collections.Generic;
-using System.Threading.Tasks;
 using Xtensive.Core;
 
 namespace Xtensive.Orm.Providers
diff --git a/Orm/Xtensive.Orm/Orm/Providers/CommandProcessing/DataReader.cs b/Orm/Xtensive.Orm/Orm/Providers/CommandProcessing/DataReader.cs
index 410e31b2e..63e4cf50c 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/CommandProcessing/DataReader.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/CommandProcessing/DataReader.cs
@@ -2,11 +2,7 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
-using System.Threading;
-using System.Threading.Tasks;
 using Tuple = Xtensive.Tuples.Tuple;
 
 namespace Xtensive.Orm.Providers
diff --git a/Orm/Xtensive.Orm/Orm/Providers/CommandProcessing/SimpleCommandProcessor.cs b/Orm/Xtensive.Orm/Orm/Providers/CommandProcessing/SimpleCommandProcessor.cs
index 64feb4857..34d7916bc 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/CommandProcessing/SimpleCommandProcessor.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/CommandProcessing/SimpleCommandProcessor.cs
@@ -4,10 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.08.20
 
-using System.Collections.Generic;
-using System.Linq;
-using System.Threading;
-using System.Threading.Tasks;
 using Xtensive.Core;
 
 namespace Xtensive.Orm.Providers
diff --git a/Orm/Xtensive.Orm/Orm/Providers/CommandProcessing/SqlLoadTask.cs b/Orm/Xtensive.Orm/Orm/Providers/CommandProcessing/SqlLoadTask.cs
index ecde7725d..3d08b77b3 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/CommandProcessing/SqlLoadTask.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/CommandProcessing/SqlLoadTask.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.08.21
 
-using System.Collections.Generic;
 using Xtensive.Core;
 using Tuple = Xtensive.Tuples.Tuple;
 
diff --git a/Orm/Xtensive.Orm/Orm/Providers/CommandProcessing/SqlPersistTask.cs b/Orm/Xtensive.Orm/Orm/Providers/CommandProcessing/SqlPersistTask.cs
index 42c319b6f..6c76bb039 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/CommandProcessing/SqlPersistTask.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/CommandProcessing/SqlPersistTask.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.08.21
 
-using System;
-using System.Collections.Generic;
 using Xtensive.Collections;
 using Xtensive.Tuples;
 using Tuple = Xtensive.Tuples.Tuple;
diff --git a/Orm/Xtensive.Orm/Orm/Providers/CommandWithDataReader.cs b/Orm/Xtensive.Orm/Orm/Providers/CommandWithDataReader.cs
index 67f40513c..a3d167455 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/CommandWithDataReader.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/CommandWithDataReader.cs
@@ -4,9 +4,7 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.03.01
 
-using System;
 using System.Data.Common;
-using System.Threading.Tasks;
 using Xtensive.Core;
 
 namespace Xtensive.Orm.Providers
diff --git a/Orm/Xtensive.Orm/Orm/Providers/CompilationService.cs b/Orm/Xtensive.Orm/Orm/Providers/CompilationService.cs
index 9c44c2c5e..e6c329dbc 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/CompilationService.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/CompilationService.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kochetov
 // Created:    2008.07.04
 
-using System;
 using Xtensive.Core;
 using Xtensive.Orm.Rse.Compilation;
 using Xtensive.Orm.Rse.Providers;
diff --git a/Orm/Xtensive.Orm/Orm/Providers/CompilerConfiguration.cs b/Orm/Xtensive.Orm/Orm/Providers/CompilerConfiguration.cs
index 46c2649f3..3a77050ce 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/CompilerConfiguration.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/CompilerConfiguration.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.02.26
 
-using System.Collections.Generic;
 
 namespace Xtensive.Orm.Providers
 {
diff --git a/Orm/Xtensive.Orm/Orm/Providers/DbCommandExtensions.cs b/Orm/Xtensive.Orm/Orm/Providers/DbCommandExtensions.cs
index 436349f46..dea94acf0 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/DbCommandExtensions.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/DbCommandExtensions.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2009.10.14
 
-using System;
 using System.Data.Common;
 using System.Text;
 
diff --git a/Orm/Xtensive.Orm/Orm/Providers/DbDataReaderAccessor.cs b/Orm/Xtensive.Orm/Orm/Providers/DbDataReaderAccessor.cs
index 40b94bde0..0483266a7 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/DbDataReaderAccessor.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/DbDataReaderAccessor.cs
@@ -4,9 +4,7 @@
 // Created by: Dmitri Maximov
 // Created:    2008.09.30
 
-using System.Collections.Generic;
 using System.Data.Common;
-using System.Linq;
 using Xtensive.Tuples;
 using Xtensive.Sql;
 using Tuple = Xtensive.Tuples.Tuple;
diff --git a/Orm/Xtensive.Orm/Orm/Providers/DomainHandler.cs b/Orm/Xtensive.Orm/Orm/Providers/DomainHandler.cs
index 6e7824d52..e7f345a0e 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/DomainHandler.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/DomainHandler.cs
@@ -4,8 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2008.05.19
 
-using System;
-using System.Collections.Generic;
 using Xtensive.Core;
 using Xtensive.Orm.Building.Builders;
 using Xtensive.Orm.Linq.MemberCompilation;
diff --git a/Orm/Xtensive.Orm/Orm/Providers/EnumerationContext.cs b/Orm/Xtensive.Orm/Orm/Providers/EnumerationContext.cs
index 5e76e5639..1f78654b5 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/EnumerationContext.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/EnumerationContext.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.08.30
 
-using System;
-using System.Collections.Generic;
 using Xtensive.Core;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Linq.Materialization;
diff --git a/Orm/Xtensive.Orm/Orm/Providers/Expressions/BooleanExpressionConverter.cs b/Orm/Xtensive.Orm/Orm/Providers/Expressions/BooleanExpressionConverter.cs
index 64fa94bb9..80b3d60ca 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/Expressions/BooleanExpressionConverter.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/Expressions/BooleanExpressionConverter.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.08.17
 
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Reflection;
 using Xtensive.Sql;
 using Xtensive.Sql.Dml;
diff --git a/Orm/Xtensive.Orm/Orm/Providers/Expressions/ExpressionProcessor.Helpers.cs b/Orm/Xtensive.Orm/Orm/Providers/Expressions/ExpressionProcessor.Helpers.cs
index ebfdf8b36..8bae309c3 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/Expressions/ExpressionProcessor.Helpers.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/Expressions/ExpressionProcessor.Helpers.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.09.26
 
-using System;
 using System.Linq.Expressions;
 using System.Reflection;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Orm/Providers/Expressions/ExpressionProcessor.cs b/Orm/Xtensive.Orm/Orm/Providers/Expressions/ExpressionProcessor.cs
index 948ec5118..6c4b9da32 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/Expressions/ExpressionProcessor.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/Expressions/ExpressionProcessor.cs
@@ -4,9 +4,6 @@
 // Created by: Alexey Kochetov
 // Created:    2008.09.05
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Linq.Expressions;
 using Xtensive.Core;
 using Xtensive.Linq;
diff --git a/Orm/Xtensive.Orm/Orm/Providers/Expressions/ExpressionTranslationContext.cs b/Orm/Xtensive.Orm/Orm/Providers/Expressions/ExpressionTranslationContext.cs
index f0ba3e8ba..e150ee317 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/Expressions/ExpressionTranslationContext.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/Expressions/ExpressionTranslationContext.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.09.18
 
-using System;
 using System.Linq.Expressions;
 using Xtensive.Sql;
 
diff --git a/Orm/Xtensive.Orm/Orm/Providers/Expressions/ExpressionTranslationHelpers.cs b/Orm/Xtensive.Orm/Orm/Providers/Expressions/ExpressionTranslationHelpers.cs
index 5d20d0792..89127ff85 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/Expressions/ExpressionTranslationHelpers.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/Expressions/ExpressionTranslationHelpers.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.09.18
 
-using System;
 using Xtensive.Reflection;
 using Xtensive.Sql;
 using Xtensive.Sql.Dml;
diff --git a/Orm/Xtensive.Orm/Orm/Providers/Expressions/MemberCompilers/DateOnlyCompilers.cs b/Orm/Xtensive.Orm/Orm/Providers/Expressions/MemberCompilers/DateOnlyCompilers.cs
index 83dd54d2a..6c67e75ee 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/Expressions/MemberCompilers/DateOnlyCompilers.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/Expressions/MemberCompilers/DateOnlyCompilers.cs
@@ -2,7 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
 using System.Linq.Expressions;
 using Xtensive.Sql;
 using Xtensive.Sql.Dml;
diff --git a/Orm/Xtensive.Orm/Orm/Providers/Expressions/MemberCompilers/DateTimeCompilers.cs b/Orm/Xtensive.Orm/Orm/Providers/Expressions/MemberCompilers/DateTimeCompilers.cs
index cadfe870f..531377ece 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/Expressions/MemberCompilers/DateTimeCompilers.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/Expressions/MemberCompilers/DateTimeCompilers.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.02.14
 
-using System;
 using Xtensive.Linq;
 using Xtensive.Sql;
 using Xtensive.Sql.Dml;
diff --git a/Orm/Xtensive.Orm/Orm/Providers/Expressions/MemberCompilers/DateTimeOffsetCompilers.cs b/Orm/Xtensive.Orm/Orm/Providers/Expressions/MemberCompilers/DateTimeOffsetCompilers.cs
index 8b816fb71..1f7bf80d8 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/Expressions/MemberCompilers/DateTimeOffsetCompilers.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/Expressions/MemberCompilers/DateTimeOffsetCompilers.cs
@@ -4,7 +4,6 @@
 // Created by: Alena Mikshina
 // Created:    2013.11.25
 
-using System;
 using Xtensive.Sql;
 using Xtensive.Sql.Dml;
 using Operator = Xtensive.Reflection.WellKnown.Operator;
diff --git a/Orm/Xtensive.Orm/Orm/Providers/Expressions/MemberCompilers/DecimalCompilers.cs b/Orm/Xtensive.Orm/Orm/Providers/Expressions/MemberCompilers/DecimalCompilers.cs
index 0aa864fad..efd83f1fa 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/Expressions/MemberCompilers/DecimalCompilers.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/Expressions/MemberCompilers/DecimalCompilers.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.02.18
 
-using System;
 using Xtensive.Linq;
 using Xtensive.Sql;
 using Xtensive.Sql.Dml;
diff --git a/Orm/Xtensive.Orm/Orm/Providers/Expressions/MemberCompilers/EnumCompilers.cs b/Orm/Xtensive.Orm/Orm/Providers/Expressions/MemberCompilers/EnumCompilers.cs
index 527eec677..735362deb 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/Expressions/MemberCompilers/EnumCompilers.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/Expressions/MemberCompilers/EnumCompilers.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2013.07.23
 
-using System;
 using Xtensive.Sql;
 using Xtensive.Sql.Dml;
 
diff --git a/Orm/Xtensive.Orm/Orm/Providers/Expressions/MemberCompilers/GuidCompilers.cs b/Orm/Xtensive.Orm/Orm/Providers/Expressions/MemberCompilers/GuidCompilers.cs
index c2d04dea7..7bb0b3097 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/Expressions/MemberCompilers/GuidCompilers.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/Expressions/MemberCompilers/GuidCompilers.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.07.10
 
-using System;
 using Xtensive.Linq;
 using Xtensive.Sql;
 using Xtensive.Sql.Dml;
diff --git a/Orm/Xtensive.Orm/Orm/Providers/Expressions/MemberCompilers/MathCompilers.cs b/Orm/Xtensive.Orm/Orm/Providers/Expressions/MemberCompilers/MathCompilers.cs
index da49f46f3..93431e216 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/Expressions/MemberCompilers/MathCompilers.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/Expressions/MemberCompilers/MathCompilers.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.02.14
 
-using System;
 using Xtensive.Linq;
 using Xtensive.Sql;
 using Xtensive.Sql.Dml;
diff --git a/Orm/Xtensive.Orm/Orm/Providers/Expressions/MemberCompilers/NullableCompilers.cs b/Orm/Xtensive.Orm/Orm/Providers/Expressions/MemberCompilers/NullableCompilers.cs
index c531a8a9a..0bf7e9a8d 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/Expressions/MemberCompilers/NullableCompilers.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/Expressions/MemberCompilers/NullableCompilers.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.02.20
 
-using System;
 using System.Linq.Expressions;
 using System.Reflection;
 using Xtensive.Linq;
diff --git a/Orm/Xtensive.Orm/Orm/Providers/Expressions/MemberCompilers/NumericCompilers.cs b/Orm/Xtensive.Orm/Orm/Providers/Expressions/MemberCompilers/NumericCompilers.cs
index 556753478..839145484 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/Expressions/MemberCompilers/NumericCompilers.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/Expressions/MemberCompilers/NumericCompilers.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.02.15
 
-using System;
 using Xtensive.Linq;
 using Xtensive.Sql;
 using Xtensive.Sql.Dml;
diff --git a/Orm/Xtensive.Orm/Orm/Providers/Expressions/MemberCompilers/StringCompilers.cs b/Orm/Xtensive.Orm/Orm/Providers/Expressions/MemberCompilers/StringCompilers.cs
index 9fd23702a..f1dc207c4 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/Expressions/MemberCompilers/StringCompilers.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/Expressions/MemberCompilers/StringCompilers.cs
@@ -4,10 +4,7 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.02.13
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
-using System.Linq;
 using System.Reflection;
 using System.Text;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Orm/Providers/Expressions/MemberCompilers/TimeOnlyCompilers.cs b/Orm/Xtensive.Orm/Orm/Providers/Expressions/MemberCompilers/TimeOnlyCompilers.cs
index 36fa6664a..4f703392a 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/Expressions/MemberCompilers/TimeOnlyCompilers.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/Expressions/MemberCompilers/TimeOnlyCompilers.cs
@@ -2,7 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
 using Xtensive.Reflection;
 using Xtensive.Sql;
 using Xtensive.Sql.Dml;
diff --git a/Orm/Xtensive.Orm/Orm/Providers/Expressions/MemberCompilers/TimeSpanCompilers.cs b/Orm/Xtensive.Orm/Orm/Providers/Expressions/MemberCompilers/TimeSpanCompilers.cs
index f98d91641..c08629714 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/Expressions/MemberCompilers/TimeSpanCompilers.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/Expressions/MemberCompilers/TimeSpanCompilers.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.02.24
 
-using System;
 using Xtensive.Reflection;
 using Xtensive.Sql;
 using Xtensive.Sql.Dml;
diff --git a/Orm/Xtensive.Orm/Orm/Providers/Expressions/MemberCompilers/VbConversionsCompilers.cs b/Orm/Xtensive.Orm/Orm/Providers/Expressions/MemberCompilers/VbConversionsCompilers.cs
index 8c82953e1..8154d7e74 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/Expressions/MemberCompilers/VbConversionsCompilers.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/Expressions/MemberCompilers/VbConversionsCompilers.cs
@@ -4,9 +4,6 @@
 // Created by: Aleksey Gamzov
 // Created:    2010.11.02
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Text;
 using Xtensive.Linq;
 using Xtensive.Sql;
diff --git a/Orm/Xtensive.Orm/Orm/Providers/Expressions/MemberCompilers/VbDateAndTimeCompilers.cs b/Orm/Xtensive.Orm/Orm/Providers/Expressions/MemberCompilers/VbDateAndTimeCompilers.cs
index c87cf8bc9..243780087 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/Expressions/MemberCompilers/VbDateAndTimeCompilers.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/Expressions/MemberCompilers/VbDateAndTimeCompilers.cs
@@ -4,9 +4,6 @@
 // Created by: Aleksey Gamzov
 // Created:    2010.11.02
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Text;
 using Xtensive.Linq;
 using Xtensive.Sql;
diff --git a/Orm/Xtensive.Orm/Orm/Providers/Expressions/QueryParameterIdentity.cs b/Orm/Xtensive.Orm/Orm/Providers/Expressions/QueryParameterIdentity.cs
index 344c1a078..f0c8d802a 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/Expressions/QueryParameterIdentity.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/Expressions/QueryParameterIdentity.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2013.12.17
 
-using System;
 using Xtensive.Core;
 using Xtensive.Sql;
 
diff --git a/Orm/Xtensive.Orm/Orm/Providers/GeneralPurposeExtensions.cs b/Orm/Xtensive.Orm/Orm/Providers/GeneralPurposeExtensions.cs
index 155fc2a0f..df58840a7 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/GeneralPurposeExtensions.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/GeneralPurposeExtensions.cs
@@ -2,7 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
 using Xtensive.Sql.Compiler;
 
 namespace Xtensive.Orm.Providers
diff --git a/Orm/Xtensive.Orm/Orm/Providers/HandlerFactory.cs b/Orm/Xtensive.Orm/Orm/Providers/HandlerFactory.cs
index 3257e05bd..241404e20 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/HandlerFactory.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/HandlerFactory.cs
@@ -4,8 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2008.06.02
 
-using System;
-using System.Collections.Generic;
 using System.Reflection;
 using Xtensive.Reflection;
 
diff --git a/Orm/Xtensive.Orm/Orm/Providers/Interfaces/IDirectSqlService.cs b/Orm/Xtensive.Orm/Orm/Providers/Interfaces/IDirectSqlService.cs
index 7fccf380f..44cb5b229 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/Interfaces/IDirectSqlService.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/Interfaces/IDirectSqlService.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2010.02.08
 
-using System;
 using System.Data.Common;
 using Xtensive.Orm.Services;
 
diff --git a/Orm/Xtensive.Orm/Orm/Providers/Interfaces/IPersistDescriptors.cs b/Orm/Xtensive.Orm/Orm/Providers/Interfaces/IPersistDescriptors.cs
index 020c2d32d..dd702b66c 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/Interfaces/IPersistDescriptors.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/Interfaces/IPersistDescriptors.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.03.22
 
-using System;
 
 namespace Xtensive.Orm.Providers
 {
diff --git a/Orm/Xtensive.Orm/Orm/Providers/Interfaces/IProviderExecutor.cs b/Orm/Xtensive.Orm/Orm/Providers/Interfaces/IProviderExecutor.cs
index d4597cc6b..3b8ae510a 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/Interfaces/IProviderExecutor.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/Interfaces/IProviderExecutor.cs
@@ -4,9 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.10.30
 
-using System.Collections.Generic;
-using System.Threading;
-using System.Threading.Tasks;
 using Xtensive.Core;
 using Tuple = Xtensive.Tuples.Tuple;
 
diff --git a/Orm/Xtensive.Orm/Orm/Providers/Interfaces/IQueryRequest.cs b/Orm/Xtensive.Orm/Orm/Providers/Interfaces/IQueryRequest.cs
index df4ee32c7..05d40dafe 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/Interfaces/IQueryRequest.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/Interfaces/IQueryRequest.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.02.25
 
-using System.Collections.Generic;
 using Xtensive.Sql.Compiler;
 
 namespace Xtensive.Orm.Providers
diff --git a/Orm/Xtensive.Orm/Orm/Providers/Interfaces/ISqlExecutor.cs b/Orm/Xtensive.Orm/Orm/Providers/Interfaces/ISqlExecutor.cs
index ec024c3a0..ba381d1fd 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/Interfaces/ISqlExecutor.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/Interfaces/ISqlExecutor.cs
@@ -4,11 +4,8 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.02.29
 
-using System.Collections.Generic;
 using System.Data;
 using System.Data.Common;
-using System.Threading;
-using System.Threading.Tasks;
 using Xtensive.Sql;
 
 namespace Xtensive.Orm.Providers
diff --git a/Orm/Xtensive.Orm/Orm/Providers/Interfaces/IStorageSequenceAccessor.cs b/Orm/Xtensive.Orm/Orm/Providers/Interfaces/IStorageSequenceAccessor.cs
index 01bc82f15..407b34e41 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/Interfaces/IStorageSequenceAccessor.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/Interfaces/IStorageSequenceAccessor.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2010.02.09
 
-using System.Collections.Generic;
 using Xtensive.Core;
 using Xtensive.Orm.Model;
 
diff --git a/Orm/Xtensive.Orm/Orm/Providers/MappingResolver.cs b/Orm/Xtensive.Orm/Orm/Providers/MappingResolver.cs
index 051585089..d20cab1e4 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/MappingResolver.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/MappingResolver.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.03.06
 
-using System.Collections.Generic;
 using Xtensive.Core;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Model;
diff --git a/Orm/Xtensive.Orm/Orm/Providers/ModelMapping.cs b/Orm/Xtensive.Orm/Orm/Providers/ModelMapping.cs
index 4e3f660c7..6bc97e116 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/ModelMapping.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/ModelMapping.cs
@@ -4,8 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2008.09.23
 
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Core;
 using Xtensive.Orm.Model;
 using Xtensive.Sql.Model;
diff --git a/Orm/Xtensive.Orm/Orm/Providers/MultidatabaseMappingResolver.cs b/Orm/Xtensive.Orm/Orm/Providers/MultidatabaseMappingResolver.cs
index 984cf9a6c..0983a9092 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/MultidatabaseMappingResolver.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/MultidatabaseMappingResolver.cs
@@ -4,9 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2014.03.13
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Upgrade;
 using Xtensive.Sql;
diff --git a/Orm/Xtensive.Orm/Orm/Providers/MultischemaMappingResolver.cs b/Orm/Xtensive.Orm/Orm/Providers/MultischemaMappingResolver.cs
index 19812c160..a96c36703 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/MultischemaMappingResolver.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/MultischemaMappingResolver.cs
@@ -4,9 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2014.03.13
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Upgrade;
 using Xtensive.Sql;
diff --git a/Orm/Xtensive.Orm/Orm/Providers/NameBuilder.cs b/Orm/Xtensive.Orm/Orm/Providers/NameBuilder.cs
index d82f34614..40495917a 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/NameBuilder.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/NameBuilder.cs
@@ -4,10 +4,7 @@
 // Created by: Dmitri Maximov
 // Created:    2007.08.27
 
-using System;
 using System.Collections.Concurrent;
-using System.Collections.Generic;
-using System.Linq;
 using System.Reflection;
 using System.Runtime.CompilerServices;
 using System.Security.Cryptography;
diff --git a/Orm/Xtensive.Orm/Orm/Providers/NullSearchConditionCompiler.cs b/Orm/Xtensive.Orm/Orm/Providers/NullSearchConditionCompiler.cs
index 8b2e85639..ce750a586 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/NullSearchConditionCompiler.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/NullSearchConditionCompiler.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2016.12.08
 
-using System;
 using Xtensive.Orm.FullTextSearchCondition.Interfaces;
 
 namespace Xtensive.Orm.Providers
diff --git a/Orm/Xtensive.Orm/Orm/Providers/PartialIndexFilterCompiler.cs b/Orm/Xtensive.Orm/Orm/Providers/PartialIndexFilterCompiler.cs
index 0d0f5ea5c..1af64513e 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/PartialIndexFilterCompiler.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/PartialIndexFilterCompiler.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2013.07.18
 
-using System.Linq;
 using Xtensive.Orm.Model;
 using Xtensive.Sql;
 using Xtensive.Sql.Dml;
diff --git a/Orm/Xtensive.Orm/Orm/Providers/Persister.cs b/Orm/Xtensive.Orm/Orm/Providers/Persister.cs
index 6d6733d02..123dcb422 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/Persister.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/Persister.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.04.02
 
-using System;
-using System.Collections.Generic;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Internals;
 using Xtensive.Tuples;
diff --git a/Orm/Xtensive.Orm/Orm/Providers/ProviderAttribute.cs b/Orm/Xtensive.Orm/Orm/Providers/ProviderAttribute.cs
index 4ed785469..620053372 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/ProviderAttribute.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/ProviderAttribute.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kochetov
 // Created:    2008.01.21
 
-using System;
 using Xtensive.Sql;
 
 namespace Xtensive.Orm.Providers
diff --git a/Orm/Xtensive.Orm/Orm/Providers/ProviderFeatures.cs b/Orm/Xtensive.Orm/Orm/Providers/ProviderFeatures.cs
index 91deae7dc..457e4ec56 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/ProviderFeatures.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/ProviderFeatures.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2009.08.28
 
-using System;
 
 namespace Xtensive.Orm.Providers
 {
diff --git a/Orm/Xtensive.Orm/Orm/Providers/ProviderInfo.cs b/Orm/Xtensive.Orm/Orm/Providers/ProviderInfo.cs
index d9169a356..5658df9c5 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/ProviderInfo.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/ProviderInfo.cs
@@ -4,9 +4,6 @@
 // Created by: Alexander Nikolaev
 // Created:    2009.06.01
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Collections;
 
 namespace Xtensive.Orm.Providers
diff --git a/Orm/Xtensive.Orm/Orm/Providers/ProviderInfoBuilder.cs b/Orm/Xtensive.Orm/Orm/Providers/ProviderInfoBuilder.cs
index 61c2da291..519fe12e0 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/ProviderInfoBuilder.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/ProviderInfoBuilder.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2010.02.11
 
-using System.Linq;
 using Xtensive.Core;
 using Xtensive.Sql;
 using Xtensive.Sql.Info;
diff --git a/Orm/Xtensive.Orm/Orm/Providers/Requests/ParameterBinding.cs b/Orm/Xtensive.Orm/Orm/Providers/Requests/ParameterBinding.cs
index aa9a06d86..11db15b45 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/Requests/ParameterBinding.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/Requests/ParameterBinding.cs
@@ -4,9 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2008.09.26
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Core;
 using Xtensive.Sql;
 using Xtensive.Sql.Dml;
diff --git a/Orm/Xtensive.Orm/Orm/Providers/Requests/PersistParameterBinding.cs b/Orm/Xtensive.Orm/Orm/Providers/Requests/PersistParameterBinding.cs
index 60032d0de..0ebd79b34 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/Requests/PersistParameterBinding.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/Requests/PersistParameterBinding.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2008.09.25
 
-using System;
 using Xtensive.Core;
 using Xtensive.Sql;
 
diff --git a/Orm/Xtensive.Orm/Orm/Providers/Requests/PersistRequest.cs b/Orm/Xtensive.Orm/Orm/Providers/Requests/PersistRequest.cs
index 8f2581035..51dfc5366 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/Requests/PersistRequest.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/Requests/PersistRequest.cs
@@ -4,8 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2008.08.22
 
-using System;
-using System.Collections.Generic;
 using Xtensive.Core;
 using Xtensive.Orm.Configuration;
 using Xtensive.Sql;
diff --git a/Orm/Xtensive.Orm/Orm/Providers/Requests/PersistRequestBuilder.cs b/Orm/Xtensive.Orm/Orm/Providers/Requests/PersistRequestBuilder.cs
index 59aa179a2..595bbe58a 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/Requests/PersistRequestBuilder.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/Requests/PersistRequestBuilder.cs
@@ -4,8 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2008.08.28
 
-using System;
-using System.Collections.Generic;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Model;
 using Xtensive.Sql;
diff --git a/Orm/Xtensive.Orm/Orm/Providers/Requests/PersistRequestBuilderContext.cs b/Orm/Xtensive.Orm/Orm/Providers/Requests/PersistRequestBuilderContext.cs
index 921b18c3c..a3d53b643 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/Requests/PersistRequestBuilderContext.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/Requests/PersistRequestBuilderContext.cs
@@ -4,8 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2008.08.29
 
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Collections;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Model;
diff --git a/Orm/Xtensive.Orm/Orm/Providers/Requests/PersistRequestBuilderTask.cs b/Orm/Xtensive.Orm/Orm/Providers/Requests/PersistRequestBuilderTask.cs
index 0acabb029..db97b7043 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/Requests/PersistRequestBuilderTask.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/Requests/PersistRequestBuilderTask.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2008.08.29
 
-using System;
 using System.Collections;
 using Xtensive.Orm.Model;
 
diff --git a/Orm/Xtensive.Orm/Orm/Providers/Requests/QueryParameterBinding.cs b/Orm/Xtensive.Orm/Orm/Providers/Requests/QueryParameterBinding.cs
index 4f6f21ad9..25ffa2c55 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/Requests/QueryParameterBinding.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/Requests/QueryParameterBinding.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2008.09.25
 
-using System;
 using Xtensive.Core;
 using Xtensive.Sql;
 
diff --git a/Orm/Xtensive.Orm/Orm/Providers/Requests/QueryRequest.cs b/Orm/Xtensive.Orm/Orm/Providers/Requests/QueryRequest.cs
index 065ff56fb..b41d7c6ed 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/Requests/QueryRequest.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/Requests/QueryRequest.cs
@@ -4,9 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2008.08.22
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Core;
 using Xtensive.Orm.Configuration;
 using Xtensive.Sql.Compiler;
diff --git a/Orm/Xtensive.Orm/Orm/Providers/Requests/QueryRequestOptions.cs b/Orm/Xtensive.Orm/Orm/Providers/Requests/QueryRequestOptions.cs
index 5c3c64379..18278ef57 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/Requests/QueryRequestOptions.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/Requests/QueryRequestOptions.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.11.13
 
-using System;
 
 namespace Xtensive.Orm.Providers
 {
diff --git a/Orm/Xtensive.Orm/Orm/Providers/Requests/QueryRowFilterParameterBinding.cs b/Orm/Xtensive.Orm/Orm/Providers/Requests/QueryRowFilterParameterBinding.cs
index cac8d390b..fc6c61f3e 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/Requests/QueryRowFilterParameterBinding.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/Requests/QueryRowFilterParameterBinding.cs
@@ -4,9 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.11.12
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Collections;
 using Xtensive.Core;
 using Xtensive.Sql;
diff --git a/Orm/Xtensive.Orm/Orm/Providers/Requests/QueryTypeIdentifierParameterBinding.cs b/Orm/Xtensive.Orm/Orm/Providers/Requests/QueryTypeIdentifierParameterBinding.cs
index b0b7705bd..274066c13 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/Requests/QueryTypeIdentifierParameterBinding.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/Requests/QueryTypeIdentifierParameterBinding.cs
@@ -3,7 +3,6 @@
 // See the License.txt file in the project root for more information.
 
 
-using System;
 using Xtensive.Core;
 using Xtensive.Sql;
 
diff --git a/Orm/Xtensive.Orm/Orm/Providers/Requests/UserQueryRequest.cs b/Orm/Xtensive.Orm/Orm/Providers/Requests/UserQueryRequest.cs
index 2f0264cf9..c53bc259d 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/Requests/UserQueryRequest.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/Requests/UserQueryRequest.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.02.25
 
-using System.Collections.Generic;
 using Xtensive.Core;
 using Xtensive.Sql.Compiler;
 
diff --git a/Orm/Xtensive.Orm/Orm/Providers/SequenceQuery.cs b/Orm/Xtensive.Orm/Orm/Providers/SequenceQuery.cs
index 5f540cefa..b54445354 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/SequenceQuery.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/SequenceQuery.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.03.07
 
-using System;
 using Xtensive.Core;
 
 namespace Xtensive.Orm.Providers
diff --git a/Orm/Xtensive.Orm/Orm/Providers/SequenceQueryBuilder.cs b/Orm/Xtensive.Orm/Orm/Providers/SequenceQueryBuilder.cs
index 6455e4a12..8d6340df8 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/SequenceQueryBuilder.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/SequenceQueryBuilder.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.03.07
 
-using System;
-using System.Collections.Generic;
 using Xtensive.Core;
 using Xtensive.Orm.Configuration;
 using Xtensive.Sql;
diff --git a/Orm/Xtensive.Orm/Orm/Providers/SessionHandler.Fetching.cs b/Orm/Xtensive.Orm/Orm/Providers/SessionHandler.Fetching.cs
index 95a73e8d0..1f6924a36 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/SessionHandler.Fetching.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/SessionHandler.Fetching.cs
@@ -4,9 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.08.19
 
-using System.Collections.Generic;
-using System.Threading;
-using System.Threading.Tasks;
 using Xtensive.Orm.Internals.Prefetch;
 using Xtensive.Orm.Model;
 using TypeInfo = Xtensive.Orm.Model.TypeInfo;
diff --git a/Orm/Xtensive.Orm/Orm/Providers/SessionHandler.References.cs b/Orm/Xtensive.Orm/Orm/Providers/SessionHandler.References.cs
index cc9b69fef..5f427d69e 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/SessionHandler.References.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/SessionHandler.References.cs
@@ -4,9 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.08.19
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Core;
 using Xtensive.Orm.Internals;
 using Xtensive.Orm.Linq;
diff --git a/Orm/Xtensive.Orm/Orm/Providers/SessionHandler.StateManagement.cs b/Orm/Xtensive.Orm/Orm/Providers/SessionHandler.StateManagement.cs
index 11ace63c6..59c7ec7c4 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/SessionHandler.StateManagement.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/SessionHandler.StateManagement.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.08.19
 
-using System.Collections.Generic;
 using Xtensive.Core;
 using Xtensive.Orm.Internals;
 using Xtensive.Orm.Model;
diff --git a/Orm/Xtensive.Orm/Orm/Providers/SessionHandler.Transactions.cs b/Orm/Xtensive.Orm/Orm/Providers/SessionHandler.Transactions.cs
index fc0078c55..c26020d21 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/SessionHandler.Transactions.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/SessionHandler.Transactions.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.08.19
 
-using System.Threading;
-using System.Threading.Tasks;
 
 
 namespace Xtensive.Orm.Providers
diff --git a/Orm/Xtensive.Orm/Orm/Providers/SessionHandler.cs b/Orm/Xtensive.Orm/Orm/Providers/SessionHandler.cs
index b6ac66b3b..6fb8bafb9 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/SessionHandler.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/SessionHandler.cs
@@ -4,11 +4,7 @@
 // Created by: Dmitri Maximov
 // Created:    2008.05.19
 
-using System;
-using System.Collections.Generic;
 using System.Data;
-using System.Threading;
-using System.Threading.Tasks;
 using Xtensive.IoC;
 using Xtensive.Orm.Internals;
 
diff --git a/Orm/Xtensive.Orm/Orm/Providers/SimpleMappingResolver.cs b/Orm/Xtensive.Orm/Orm/Providers/SimpleMappingResolver.cs
index fdd9c8d25..5baec3094 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/SimpleMappingResolver.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/SimpleMappingResolver.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2014.03.13
 
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Orm.Upgrade;
 using Xtensive.Sql;
 using Xtensive.Sql.Info;
diff --git a/Orm/Xtensive.Orm/Orm/Providers/SqlCompiler.Aggregate.cs b/Orm/Xtensive.Orm/Orm/Providers/SqlCompiler.Aggregate.cs
index b2612ffc8..37f46cc8b 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/SqlCompiler.Aggregate.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/SqlCompiler.Aggregate.cs
@@ -4,9 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.11.13
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Sql;
 using Xtensive.Sql.Dml;
 using Xtensive.Orm.Rse;
diff --git a/Orm/Xtensive.Orm/Orm/Providers/SqlCompiler.Apply.cs b/Orm/Xtensive.Orm/Orm/Providers/SqlCompiler.Apply.cs
index 80b5fd090..de4cd088f 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/SqlCompiler.Apply.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/SqlCompiler.Apply.cs
@@ -4,9 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.11.13
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Core;
 using Xtensive.Orm;
 using Xtensive.Sql;
diff --git a/Orm/Xtensive.Orm/Orm/Providers/SqlCompiler.Helpers.cs b/Orm/Xtensive.Orm/Orm/Providers/SqlCompiler.Helpers.cs
index f39c84217..b770995ea 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/SqlCompiler.Helpers.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/SqlCompiler.Helpers.cs
@@ -4,9 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.11.13
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Linq.Expressions;
 using Xtensive.Core;
 using Xtensive.Orm.Rse;
diff --git a/Orm/Xtensive.Orm/Orm/Providers/SqlCompiler.Include.cs b/Orm/Xtensive.Orm/Orm/Providers/SqlCompiler.Include.cs
index 10d388a01..9da5c7c76 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/SqlCompiler.Include.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/SqlCompiler.Include.cs
@@ -4,9 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.11.13
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Core;
 using Tuple = Xtensive.Tuples.Tuple;
 using Xtensive.Sql;
diff --git a/Orm/Xtensive.Orm/Orm/Providers/SqlCompiler.Index.cs b/Orm/Xtensive.Orm/Orm/Providers/SqlCompiler.Index.cs
index abf2bf379..8006b8dd7 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/SqlCompiler.Index.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/SqlCompiler.Index.cs
@@ -4,10 +4,7 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.11.13
 
-using System;
 using System.Collections.Concurrent;
-using System.Collections.Generic;
-using System.Linq;
 using System.Linq.Expressions;
 using Xtensive.Core;
 using Xtensive.Linq;
diff --git a/Orm/Xtensive.Orm/Orm/Providers/SqlCompiler.NotSupported.cs b/Orm/Xtensive.Orm/Orm/Providers/SqlCompiler.NotSupported.cs
index 6d6312b87..b7cd364c8 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/SqlCompiler.NotSupported.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/SqlCompiler.NotSupported.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.11.13
 
-using System;
 using Xtensive.Orm.Rse.Providers;
 
 namespace Xtensive.Orm.Providers
diff --git a/Orm/Xtensive.Orm/Orm/Providers/SqlCompiler.Paging.cs b/Orm/Xtensive.Orm/Orm/Providers/SqlCompiler.Paging.cs
index b56910907..858fe41e3 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/SqlCompiler.Paging.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/SqlCompiler.Paging.cs
@@ -4,9 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.11.13
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Core;
 using Xtensive.Sql;
 using Xtensive.Sql.Dml;
diff --git a/Orm/Xtensive.Orm/Orm/Providers/SqlCompiler.cs b/Orm/Xtensive.Orm/Orm/Providers/SqlCompiler.cs
index 6ccd51777..3f17a92de 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/SqlCompiler.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/SqlCompiler.cs
@@ -4,9 +4,6 @@
 // Created by: Vakhtina Elena
 // Created:    2009.02.13
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Collections;
 using Xtensive.Core;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm/Orm/Providers/SqlExecutor.cs b/Orm/Xtensive.Orm/Orm/Providers/SqlExecutor.cs
index e81f6f1cf..d6eab19a0 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/SqlExecutor.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/SqlExecutor.cs
@@ -4,12 +4,8 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.02.29
 
-using System.Collections.Generic;
 using System.Data;
 using System.Data.Common;
-using System.Linq;
-using System.Threading;
-using System.Threading.Tasks;
 using Xtensive.Core;
 using Xtensive.IoC;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm/Orm/Providers/SqlIncludeProvider.cs b/Orm/Xtensive.Orm/Orm/Providers/SqlIncludeProvider.cs
index 2cd816488..1df4f968e 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/SqlIncludeProvider.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/SqlIncludeProvider.cs
@@ -4,14 +4,9 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.11.13
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Core;
 using Tuple = Xtensive.Tuples.Tuple;
 using Xtensive.Orm.Rse.Providers;
-using System.Threading.Tasks;
-using System.Threading;
 
 namespace Xtensive.Orm.Providers
 {
diff --git a/Orm/Xtensive.Orm/Orm/Providers/SqlProvider.cs b/Orm/Xtensive.Orm/Orm/Providers/SqlProvider.cs
index 227990d31..d6f42027c 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/SqlProvider.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/SqlProvider.cs
@@ -4,13 +4,10 @@
 // Created by: Alexey Kochetov
 // Created:    2008.07.11
 
-using System.Linq;
 using Xtensive.Core;
 using Xtensive.Sql;
 using Xtensive.Sql.Dml;
 using Xtensive.Orm.Rse.Providers;
-using System.Threading;
-using System.Threading.Tasks;
 
 namespace Xtensive.Orm.Providers
 {
diff --git a/Orm/Xtensive.Orm/Orm/Providers/SqlProviderPreparer.cs b/Orm/Xtensive.Orm/Orm/Providers/SqlProviderPreparer.cs
index 850461513..02351b907 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/SqlProviderPreparer.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/SqlProviderPreparer.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.01.29
 
-using System;
 using Xtensive.Core;
 using Xtensive.Orm.Rse;
 using Xtensive.Orm.Rse.Compilation;
diff --git a/Orm/Xtensive.Orm/Orm/Providers/SqlSelectProcessor.cs b/Orm/Xtensive.Orm/Orm/Providers/SqlSelectProcessor.cs
index e8e098b63..a7e9db678 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/SqlSelectProcessor.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/SqlSelectProcessor.cs
@@ -1,5 +1,3 @@
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Core;
 using Xtensive.Sql;
 using Xtensive.Sql.Ddl;
diff --git a/Orm/Xtensive.Orm/Orm/Providers/SqlSessionHandler.Fetching.cs b/Orm/Xtensive.Orm/Orm/Providers/SqlSessionHandler.Fetching.cs
index d5069a926..b190962d1 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/SqlSessionHandler.Fetching.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/SqlSessionHandler.Fetching.cs
@@ -4,9 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.08.19
 
-using System.Collections.Generic;
-using System.Threading;
-using System.Threading.Tasks;
 using Xtensive.Orm.Internals.Prefetch;
 using Xtensive.Orm.Model;
 using TypeInfo = Xtensive.Orm.Model.TypeInfo;
diff --git a/Orm/Xtensive.Orm/Orm/Providers/SqlSessionHandler.IDirectSqlService.cs b/Orm/Xtensive.Orm/Orm/Providers/SqlSessionHandler.IDirectSqlService.cs
index d5e3b5788..5fed3eb4e 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/SqlSessionHandler.IDirectSqlService.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/SqlSessionHandler.IDirectSqlService.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2010.02.09
 
-using System;
 using System.Data.Common;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Orm/Providers/SqlSessionHandler.IProviderExecutor.cs b/Orm/Xtensive.Orm/Orm/Providers/SqlSessionHandler.IProviderExecutor.cs
index a2a2a85d6..a93700dbd 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/SqlSessionHandler.IProviderExecutor.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/SqlSessionHandler.IProviderExecutor.cs
@@ -4,10 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2010.02.09
 
-using System.Collections.Generic;
-using System.Linq;
-using System.Threading;
-using System.Threading.Tasks;
 using Xtensive.Core;
 using Xtensive.Orm.Rse.Providers;
 using Tuple = Xtensive.Tuples.Tuple;
diff --git a/Orm/Xtensive.Orm/Orm/Providers/SqlSessionHandler.cs b/Orm/Xtensive.Orm/Orm/Providers/SqlSessionHandler.cs
index 99cfd40aa..903fc7599 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/SqlSessionHandler.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/SqlSessionHandler.cs
@@ -4,11 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2008.05.20
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Threading;
-using System.Threading.Tasks;
 using Xtensive.IoC;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Internals;
diff --git a/Orm/Xtensive.Orm/Orm/Providers/SqlStoreProvider.cs b/Orm/Xtensive.Orm/Orm/Providers/SqlStoreProvider.cs
index a71278390..cac333e99 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/SqlStoreProvider.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/SqlStoreProvider.cs
@@ -4,8 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2008.09.05
 
-using System.Threading;
-using System.Threading.Tasks;
 using Xtensive.Orm.Rse.Providers;
 
 namespace Xtensive.Orm.Providers
diff --git a/Orm/Xtensive.Orm/Orm/Providers/SqlTemporaryDataProvider.cs b/Orm/Xtensive.Orm/Orm/Providers/SqlTemporaryDataProvider.cs
index c3415d52c..5380f638e 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/SqlTemporaryDataProvider.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/SqlTemporaryDataProvider.cs
@@ -4,14 +4,10 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.11.13
 
-using System;
 using Xtensive.Core;
-using System.Collections.Generic;
 using Xtensive.Tuples;
 using Tuple = Xtensive.Tuples.Tuple;
 using Xtensive.Orm.Rse.Providers;
-using System.Threading.Tasks;
-using System.Threading;
 
 namespace Xtensive.Orm.Providers
 {
diff --git a/Orm/Xtensive.Orm/Orm/Providers/StorageDriver.Operations.cs b/Orm/Xtensive.Orm/Orm/Providers/StorageDriver.Operations.cs
index d3eaf5b03..be7432521 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/StorageDriver.Operations.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/StorageDriver.Operations.cs
@@ -4,11 +4,8 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.08.14
 
-using System;
 using System.Data;
 using System.Data.Common;
-using System.Threading;
-using System.Threading.Tasks;
 using Xtensive.Orm.Configuration;
 using Xtensive.Sql;
 
diff --git a/Orm/Xtensive.Orm/Orm/Providers/StorageDriver.ValueTypeMapping.cs b/Orm/Xtensive.Orm/Orm/Providers/StorageDriver.ValueTypeMapping.cs
index 2d10f9878..e0009cee6 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/StorageDriver.ValueTypeMapping.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/StorageDriver.ValueTypeMapping.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.08.14
 
-using System;
 using Xtensive.Sql;
 using Xtensive.Orm.Model;
 
diff --git a/Orm/Xtensive.Orm/Orm/Providers/StorageDriver.cs b/Orm/Xtensive.Orm/Orm/Providers/StorageDriver.cs
index 363078b2d..5c87a33ff 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/StorageDriver.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/StorageDriver.cs
@@ -4,12 +4,7 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.08.14
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Linq.Expressions;
-using System.Threading;
-using System.Threading.Tasks;
 using System.Reflection;
 using Xtensive.Core;
 using Xtensive.Linq;
diff --git a/Orm/Xtensive.Orm/Orm/Providers/StorageExceptionBuilder.cs b/Orm/Xtensive.Orm/Orm/Providers/StorageExceptionBuilder.cs
index ebb178a63..8750c2623 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/StorageExceptionBuilder.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/StorageExceptionBuilder.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.02.25
 
-using System;
-using System.Linq;
 using System.Text;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Model;
diff --git a/Orm/Xtensive.Orm/Orm/Providers/StorageSequenceAccessor.cs b/Orm/Xtensive.Orm/Orm/Providers/StorageSequenceAccessor.cs
index b8e44781e..c624c812a 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/StorageSequenceAccessor.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/StorageSequenceAccessor.cs
@@ -4,9 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2010.09.13
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Core;
 using Xtensive.IoC;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm/Orm/Providers/TemporaryTables/TemporaryTableDescriptor.cs b/Orm/Xtensive.Orm/Orm/Providers/TemporaryTables/TemporaryTableDescriptor.cs
index 85b8d4985..45bdbcfce 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/TemporaryTables/TemporaryTableDescriptor.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/TemporaryTables/TemporaryTableDescriptor.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.11.12
 
-using System;
 using Xtensive.Core;
 
 using Xtensive.Tuples;
diff --git a/Orm/Xtensive.Orm/Orm/Providers/TemporaryTables/TemporaryTableManager.cs b/Orm/Xtensive.Orm/Orm/Providers/TemporaryTables/TemporaryTableManager.cs
index f369193e5..e1c0d6cac 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/TemporaryTables/TemporaryTableManager.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/TemporaryTables/TemporaryTableManager.cs
@@ -4,9 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.11.12
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Core;
 using Xtensive.Reflection;
 using Xtensive.Sql;
diff --git a/Orm/Xtensive.Orm/Orm/Providers/TemporaryTables/TemporaryTableStateRegistry.cs b/Orm/Xtensive.Orm/Orm/Providers/TemporaryTables/TemporaryTableStateRegistry.cs
index 4752a0a12..6429d198e 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/TemporaryTables/TemporaryTableStateRegistry.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/TemporaryTables/TemporaryTableStateRegistry.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.11.12
 
-using System.Collections.Generic;
 
 namespace Xtensive.Orm.Providers
 {
diff --git a/Orm/Xtensive.Orm/Orm/Query.cs b/Orm/Xtensive.Orm/Orm/Query.cs
index 2a399d777..0c630441f 100644
--- a/Orm/Xtensive.Orm/Orm/Query.cs
+++ b/Orm/Xtensive.Orm/Orm/Query.cs
@@ -4,13 +4,8 @@
 // Created by: Dmitri Maximov
 // Created:    2009.07.27
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Linq.Expressions;
 using System.Reflection;
-using System.Threading;
-using System.Threading.Tasks;
 using JetBrains.Annotations;
 using Xtensive.Orm.FullTextSearchCondition.Interfaces;
 using Xtensive.Orm.FullTextSearchCondition.Nodes;
diff --git a/Orm/Xtensive.Orm/Orm/QueryEndpoint.cs b/Orm/Xtensive.Orm/Orm/QueryEndpoint.cs
index 19c56ad48..03402eefa 100644
--- a/Orm/Xtensive.Orm/Orm/QueryEndpoint.cs
+++ b/Orm/Xtensive.Orm/Orm/QueryEndpoint.cs
@@ -2,13 +2,8 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Linq.Expressions;
 using System.Reflection;
-using System.Threading;
-using System.Threading.Tasks;
 using JetBrains.Annotations;
 using Xtensive.Core;
 using Xtensive.Orm.FullTextSearchCondition.Interfaces;
diff --git a/Orm/Xtensive.Orm/Orm/QueryEventArgs.cs b/Orm/Xtensive.Orm/Orm/QueryEventArgs.cs
index b95eaa36c..2446970a6 100644
--- a/Orm/Xtensive.Orm/Orm/QueryEventArgs.cs
+++ b/Orm/Xtensive.Orm/Orm/QueryEventArgs.cs
@@ -2,7 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
 using System.Linq.Expressions;
 
 
diff --git a/Orm/Xtensive.Orm/Orm/QueryResult.cs b/Orm/Xtensive.Orm/Orm/QueryResult.cs
index 7a83cc87e..94017ed40 100644
--- a/Orm/Xtensive.Orm/Orm/QueryResult.cs
+++ b/Orm/Xtensive.Orm/Orm/QueryResult.cs
@@ -2,9 +2,7 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
 using JetBrains.Annotations;
 using Xtensive.Orm.Linq.Materialization;
 
diff --git a/Orm/Xtensive.Orm/Orm/QueryResultExtensions.cs b/Orm/Xtensive.Orm/Orm/QueryResultExtensions.cs
index fb7a99d9d..5a040c937 100644
--- a/Orm/Xtensive.Orm/Orm/QueryResultExtensions.cs
+++ b/Orm/Xtensive.Orm/Orm/QueryResultExtensions.cs
@@ -2,8 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Linq;
 using Xtensive.Orm.Linq.Expressions;
 
 namespace Xtensive.Orm
diff --git a/Orm/Xtensive.Orm/Orm/QueryRootBuilder.cs b/Orm/Xtensive.Orm/Orm/QueryRootBuilder.cs
index b35e575d7..6364acc2a 100644
--- a/Orm/Xtensive.Orm/Orm/QueryRootBuilder.cs
+++ b/Orm/Xtensive.Orm/Orm/QueryRootBuilder.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.02.23
 
-using System;
 using System.Linq.Expressions;
 using Xtensive.Reflection;
 
diff --git a/Orm/Xtensive.Orm/Orm/QueryableExtensions.Async.cs b/Orm/Xtensive.Orm/Orm/QueryableExtensions.Async.cs
index 8338ef715..b120e1d0f 100644
--- a/Orm/Xtensive.Orm/Orm/QueryableExtensions.Async.cs
+++ b/Orm/Xtensive.Orm/Orm/QueryableExtensions.Async.cs
@@ -2,13 +2,8 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Linq.Expressions;
 using System.Reflection;
-using System.Threading;
-using System.Threading.Tasks;
 using Xtensive.Core;
 using Xtensive.Linq;
 using Xtensive.Orm.Linq;
diff --git a/Orm/Xtensive.Orm/Orm/QueryableExtensions.cs b/Orm/Xtensive.Orm/Orm/QueryableExtensions.cs
index 250ff8372..12521140f 100644
--- a/Orm/Xtensive.Orm/Orm/QueryableExtensions.cs
+++ b/Orm/Xtensive.Orm/Orm/QueryableExtensions.cs
@@ -4,15 +4,10 @@
 // Created by: Alexey Gamzov
 // Created:    2009.05.06
 
-using System;
-using System.Collections.Generic;
 using System.IO;
-using System.Linq;
 using System.Linq.Expressions;
 using System.Reflection;
 using System.Runtime.CompilerServices;
-using System.Threading;
-using System.Threading.Tasks;
 using JetBrains.Annotations;
 using Xtensive.Core;
 using Xtensive.Orm.Internals;
diff --git a/Orm/Xtensive.Orm/Orm/Record.cs b/Orm/Xtensive.Orm/Orm/Record.cs
index 039867ca6..2865a735e 100644
--- a/Orm/Xtensive.Orm/Orm/Record.cs
+++ b/Orm/Xtensive.Orm/Orm/Record.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Kochetov
 // Created:    2008.12.30
 
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Core;
 using Xtensive.Tuples;
 using Xtensive.Orm.Internals;
diff --git a/Orm/Xtensive.Orm/Orm/RecycledFieldDefinition.cs b/Orm/Xtensive.Orm/Orm/RecycledFieldDefinition.cs
index 4ff6cf1be..413d2a9d5 100644
--- a/Orm/Xtensive.Orm/Orm/RecycledFieldDefinition.cs
+++ b/Orm/Xtensive.Orm/Orm/RecycledFieldDefinition.cs
@@ -4,7 +4,6 @@
 // Created by: Andrey Turkov
 // Created:    2013.08.21
 
-using System;
 using Xtensive.Core;
 
 namespace Xtensive.Orm
diff --git a/Orm/Xtensive.Orm/Orm/Ref.cs b/Orm/Xtensive.Orm/Orm/Ref.cs
index eb468d5ca..1ce5c33d9 100644
--- a/Orm/Xtensive.Orm/Orm/Ref.cs
+++ b/Orm/Xtensive.Orm/Orm/Ref.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2009.12.15
 
-using System;
 using System.Diagnostics;
 using System.Runtime.Serialization;
 using System.Security;
diff --git a/Orm/Xtensive.Orm/Orm/ReferenceFinder.cs b/Orm/Xtensive.Orm/Orm/ReferenceFinder.cs
index 090eb40d1..26aede806 100644
--- a/Orm/Xtensive.Orm/Orm/ReferenceFinder.cs
+++ b/Orm/Xtensive.Orm/Orm/ReferenceFinder.cs
@@ -4,9 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2009.09.10
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Collections;
 using Xtensive.Core;
 using Xtensive.Orm.Model;
diff --git a/Orm/Xtensive.Orm/Orm/ReferenceInfo.cs b/Orm/Xtensive.Orm/Orm/ReferenceInfo.cs
index 254f89a75..cba910f6f 100644
--- a/Orm/Xtensive.Orm/Orm/ReferenceInfo.cs
+++ b/Orm/Xtensive.Orm/Orm/ReferenceInfo.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2009.09.10
 
-using System;
 
 using Xtensive.Orm.Model;
 
diff --git a/Orm/Xtensive.Orm/Orm/Rse/AggregateColumn.cs b/Orm/Xtensive.Orm/Orm/Rse/AggregateColumn.cs
index 0a3708fba..6b2283fb3 100644
--- a/Orm/Xtensive.Orm/Orm/Rse/AggregateColumn.cs
+++ b/Orm/Xtensive.Orm/Orm/Rse/AggregateColumn.cs
@@ -4,7 +4,6 @@
 // Created by: Elena Vakhtina
 // Created:    2008.09.11
 
-using System;
 
 namespace Xtensive.Orm.Rse
 {
diff --git a/Orm/Xtensive.Orm/Orm/Rse/AggregateColumnDescriptor.cs b/Orm/Xtensive.Orm/Orm/Rse/AggregateColumnDescriptor.cs
index d01818cb5..8ef041675 100644
--- a/Orm/Xtensive.Orm/Orm/Rse/AggregateColumnDescriptor.cs
+++ b/Orm/Xtensive.Orm/Orm/Rse/AggregateColumnDescriptor.cs
@@ -4,7 +4,6 @@
 // Created by: Elena Vakhtina
 // Created:    2008.09.11
 
-using System;
 
 using Xtensive.Orm.Rse;
 
diff --git a/Orm/Xtensive.Orm/Orm/Rse/ApplyParameter.cs b/Orm/Xtensive.Orm/Orm/Rse/ApplyParameter.cs
index bbcffc965..51355de3d 100644
--- a/Orm/Xtensive.Orm/Orm/Rse/ApplyParameter.cs
+++ b/Orm/Xtensive.Orm/Orm/Rse/ApplyParameter.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.04.15
 
-using System;
 using System.Diagnostics;
 using System.Runtime.Serialization;
 using System.Xml.Serialization;
diff --git a/Orm/Xtensive.Orm/Orm/Rse/CalculatedColumn.cs b/Orm/Xtensive.Orm/Orm/Rse/CalculatedColumn.cs
index 3c0016062..687466dee 100644
--- a/Orm/Xtensive.Orm/Orm/Rse/CalculatedColumn.cs
+++ b/Orm/Xtensive.Orm/Orm/Rse/CalculatedColumn.cs
@@ -4,7 +4,6 @@
 // Created by: Elena Vakhtina
 // Created:    2008.09.09
 
-using System;
 using System.Linq.Expressions;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Orm/Rse/CalculatedColumnDescriptor.cs b/Orm/Xtensive.Orm/Orm/Rse/CalculatedColumnDescriptor.cs
index 22f2a63c6..56ae3f49c 100644
--- a/Orm/Xtensive.Orm/Orm/Rse/CalculatedColumnDescriptor.cs
+++ b/Orm/Xtensive.Orm/Orm/Rse/CalculatedColumnDescriptor.cs
@@ -4,7 +4,6 @@
 // Created by: Elena Vakhtina
 // Created:    2008.09.09
 
-using System;
 using System.Linq.Expressions;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Orm/Rse/Column.cs b/Orm/Xtensive.Orm/Orm/Rse/Column.cs
index fad40cca1..389aa36b2 100644
--- a/Orm/Xtensive.Orm/Orm/Rse/Column.cs
+++ b/Orm/Xtensive.Orm/Orm/Rse/Column.cs
@@ -4,7 +4,6 @@
 // Created by: Elena Vakhtina
 // Created:    2008.09.09
 
-using System;
 
 
 namespace Xtensive.Orm.Rse
diff --git a/Orm/Xtensive.Orm/Orm/Rse/ColumnCollection.cs b/Orm/Xtensive.Orm/Orm/Rse/ColumnCollection.cs
index fafdc6fe2..b5a3aa918 100644
--- a/Orm/Xtensive.Orm/Orm/Rse/ColumnCollection.cs
+++ b/Orm/Xtensive.Orm/Orm/Rse/ColumnCollection.cs
@@ -4,10 +4,7 @@
 // Created by: Alexey Kochetov
 // Created:    2007.09.24
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Core;
 
 
diff --git a/Orm/Xtensive.Orm/Orm/Rse/ColumnGroupCollection.cs b/Orm/Xtensive.Orm/Orm/Rse/ColumnGroupCollection.cs
index 6bd6d03bd..bcbbd3801 100644
--- a/Orm/Xtensive.Orm/Orm/Rse/ColumnGroupCollection.cs
+++ b/Orm/Xtensive.Orm/Orm/Rse/ColumnGroupCollection.cs
@@ -4,11 +4,8 @@
 // Created by: Alex Kofman
 // Created:    2008.08.07
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
 using System.Diagnostics;
-using System.Linq;
 using Xtensive.Core;
 using Xtensive.Orm.Model;
 
diff --git a/Orm/Xtensive.Orm/Orm/Rse/CompilableProviderExtensions.cs b/Orm/Xtensive.Orm/Orm/Rse/CompilableProviderExtensions.cs
index 3d9883281..28e844c78 100644
--- a/Orm/Xtensive.Orm/Orm/Rse/CompilableProviderExtensions.cs
+++ b/Orm/Xtensive.Orm/Orm/Rse/CompilableProviderExtensions.cs
@@ -4,10 +4,7 @@
 // Created by: Alexey Kochetov
 // Created:    2008.05.08
 
-using System;
-using System.Collections.Generic;
 using System.Globalization;
-using System.Linq;
 using System.Linq.Expressions;
 using Xtensive.Collections;
 using Xtensive.Comparison;
diff --git a/Orm/Xtensive.Orm/Orm/Rse/Compilation/Compiler.cs b/Orm/Xtensive.Orm/Orm/Rse/Compilation/Compiler.cs
index fd8e92e4e..8c26d21e2 100644
--- a/Orm/Xtensive.Orm/Orm/Rse/Compilation/Compiler.cs
+++ b/Orm/Xtensive.Orm/Orm/Rse/Compilation/Compiler.cs
@@ -1,6 +1,3 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Orm.Rse.Providers;
 
 namespace Xtensive.Orm.Rse.Compilation
diff --git a/Orm/Xtensive.Orm/Orm/Rse/Compilation/CompositePostCompiler.cs b/Orm/Xtensive.Orm/Orm/Rse/Compilation/CompositePostCompiler.cs
index 0c781c76b..a155935bc 100644
--- a/Orm/Xtensive.Orm/Orm/Rse/Compilation/CompositePostCompiler.cs
+++ b/Orm/Xtensive.Orm/Orm/Rse/Compilation/CompositePostCompiler.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.01.29
 
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Orm.Rse.Providers;
 
 namespace Xtensive.Orm.Rse.Compilation
diff --git a/Orm/Xtensive.Orm/Orm/Rse/Compilation/CompositePreCompiler.cs b/Orm/Xtensive.Orm/Orm/Rse/Compilation/CompositePreCompiler.cs
index 9af56d942..14c50730a 100644
--- a/Orm/Xtensive.Orm/Orm/Rse/Compilation/CompositePreCompiler.cs
+++ b/Orm/Xtensive.Orm/Orm/Rse/Compilation/CompositePreCompiler.cs
@@ -4,8 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.03.30
 
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Orm.Rse.Providers;
 
 namespace Xtensive.Orm.Rse.Compilation
diff --git a/Orm/Xtensive.Orm/Orm/Rse/MappedColumn.cs b/Orm/Xtensive.Orm/Orm/Rse/MappedColumn.cs
index 445a5f70b..ecadb743b 100644
--- a/Orm/Xtensive.Orm/Orm/Rse/MappedColumn.cs
+++ b/Orm/Xtensive.Orm/Orm/Rse/MappedColumn.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kochetov
 // Created:    2007.09.21
 
-using System;
 using Xtensive.Orm.Model;
 
 namespace Xtensive.Orm.Rse
diff --git a/Orm/Xtensive.Orm/Orm/Rse/ProviderExtensions.cs b/Orm/Xtensive.Orm/Orm/Rse/ProviderExtensions.cs
index 3d8219476..f43b44ea6 100644
--- a/Orm/Xtensive.Orm/Orm/Rse/ProviderExtensions.cs
+++ b/Orm/Xtensive.Orm/Orm/Rse/ProviderExtensions.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2010.09.13
 
-using System;
 using Xtensive.Core;
 using Xtensive.Orm.Rse.Providers;
 
diff --git a/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/AggregateProvider.cs b/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/AggregateProvider.cs
index 28ea1b147..e0a959974 100644
--- a/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/AggregateProvider.cs
+++ b/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/AggregateProvider.cs
@@ -4,9 +4,6 @@
 // Created by: Elena Vakhtina
 // Created:    2008.09.18
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Collections;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/AliasProvider.cs b/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/AliasProvider.cs
index 46eee42e6..e22dd0093 100644
--- a/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/AliasProvider.cs
+++ b/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/AliasProvider.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kochetov
 // Created:    2008.07.03
 
-using System;
 using Xtensive.Collections;
 
 using Xtensive.Orm.Rse.Providers;
diff --git a/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/ApplyProvider.cs b/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/ApplyProvider.cs
index 6dfaf0f40..60fd0aa95 100644
--- a/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/ApplyProvider.cs
+++ b/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/ApplyProvider.cs
@@ -4,9 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.02.16
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Collections;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/BinaryProvider.cs b/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/BinaryProvider.cs
index c209d1e6c..0d1a6c3ec 100644
--- a/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/BinaryProvider.cs
+++ b/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/BinaryProvider.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kochetov
 // Created:    2008.07.22
 
-using System;
 using Xtensive.Core;
 
 
diff --git a/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/CalculateProvider.cs b/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/CalculateProvider.cs
index 8a8914d45..403edfc08 100644
--- a/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/CalculateProvider.cs
+++ b/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/CalculateProvider.cs
@@ -4,7 +4,6 @@
 // Created by: Elena Vakhtina
 // Created:    2008.09.09
 
-using System;
 using Xtensive.Core;
 
 using Xtensive.Tuples.Transform;
diff --git a/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/ConcatProvider.cs b/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/ConcatProvider.cs
index 57a743908..ba7ff79c8 100644
--- a/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/ConcatProvider.cs
+++ b/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/ConcatProvider.cs
@@ -4,12 +4,9 @@
 // Created by: Elena Vakhtina
 // Created:    2009.04.01
 
-using System;
-using System.Collections.Generic;
 using Xtensive.Collections;
 
 
-using System.Linq;
 
 namespace Xtensive.Orm.Rse.Providers
 {
diff --git a/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/ContainsTableProvider.cs b/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/ContainsTableProvider.cs
index d1922125e..0e23f6769 100644
--- a/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/ContainsTableProvider.cs
+++ b/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/ContainsTableProvider.cs
@@ -2,9 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Collections;
 using Xtensive.Core;
 using Xtensive.Orm.Model;
diff --git a/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/DistinctProvider.cs b/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/DistinctProvider.cs
index f8fa7fbb3..81d3c2153 100644
--- a/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/DistinctProvider.cs
+++ b/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/DistinctProvider.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2009.01.27
 
-using System;
 
 
 namespace Xtensive.Orm.Rse.Providers
diff --git a/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/ExceptProvider.cs b/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/ExceptProvider.cs
index 455b8f3a3..c4e1d3252 100644
--- a/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/ExceptProvider.cs
+++ b/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/ExceptProvider.cs
@@ -4,7 +4,6 @@
 // Created by: Elena Vakhtina
 // Created:    2009.04.01
 
-using System;
 using System.Diagnostics;
 using Xtensive.Collections;
 
diff --git a/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/ExistenceProvider.cs b/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/ExistenceProvider.cs
index b27996056..5a7885622 100644
--- a/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/ExistenceProvider.cs
+++ b/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/ExistenceProvider.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.03.20
 
-using System;
 using System.Diagnostics;
 using Xtensive.Collections;
 using Xtensive.Reflection;
diff --git a/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/FilterProvider.cs b/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/FilterProvider.cs
index dae6ee6d2..99d88b4ac 100644
--- a/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/FilterProvider.cs
+++ b/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/FilterProvider.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kochetov
 // Created:    2008.07.03
 
-using System;
 using System.Linq.Expressions;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/FreeTextProvider.cs b/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/FreeTextProvider.cs
index c96b79b04..fc315bd47 100644
--- a/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/FreeTextProvider.cs
+++ b/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/FreeTextProvider.cs
@@ -4,9 +4,7 @@
 // Created by: Alexey Gamzov
 // Created:    2009.12.28
 
-using System;
 using System.Diagnostics;
-using System.Linq;
 using Xtensive.Collections;
 using Xtensive.Core;
 using Xtensive.Orm.Model;
diff --git a/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/IncludeProvider.cs b/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/IncludeProvider.cs
index 44d508b7b..8a6d327e3 100644
--- a/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/IncludeProvider.cs
+++ b/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/IncludeProvider.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2009.10.22
 
-using System;
-using System.Collections.Generic;
 using System.Diagnostics;
 using System.Linq.Expressions;
 using Xtensive.Core;
@@ -13,7 +11,6 @@
 using Xtensive.Tuples;
 using Tuple = Xtensive.Tuples.Tuple;
 using Xtensive.Tuples.Transform;
-using System.Linq;
 using Xtensive.Reflection;
 
 namespace Xtensive.Orm.Rse.Providers
diff --git a/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/IndexProvider.cs b/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/IndexProvider.cs
index 9c3dee417..8df1be81c 100644
--- a/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/IndexProvider.cs
+++ b/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/IndexProvider.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kochetov
 // Created:    2008.07.03
 
-using System;
 using Xtensive.Collections;
 using Xtensive.Orm.Model;
 using Xtensive.Orm.Rse.Compilation;
diff --git a/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/IntersectProvider.cs b/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/IntersectProvider.cs
index 540e26ccc..f4cfe1ea7 100644
--- a/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/IntersectProvider.cs
+++ b/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/IntersectProvider.cs
@@ -4,7 +4,6 @@
 // Created by: Elena Vakhtina
 // Created:    2009.04.01
 
-using System;
 using System.Diagnostics;
 using Xtensive.Collections;
 
diff --git a/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/JoinProvider.cs b/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/JoinProvider.cs
index 0d389d3e1..adaddced5 100644
--- a/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/JoinProvider.cs
+++ b/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/JoinProvider.cs
@@ -4,9 +4,6 @@
 // Created by: Alexey Kochetov
 // Created:    2008.07.03
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Collections;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/LockProvider.cs b/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/LockProvider.cs
index 17d7bcb97..9cb655481 100644
--- a/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/LockProvider.cs
+++ b/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/LockProvider.cs
@@ -4,7 +4,6 @@
 // Created by: Alexander Nikolaev
 // Created:    2009.08.24
 
-using System;
 
 
 namespace Xtensive.Orm.Rse.Providers
diff --git a/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/OrderProviderBase.cs b/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/OrderProviderBase.cs
index 661f8c9b4..fb9f2e490 100644
--- a/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/OrderProviderBase.cs
+++ b/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/OrderProviderBase.cs
@@ -4,10 +4,7 @@
 // Created by: Alexey Kochetov
 // Created:    2008.07.08
 
-using System;
-using System.Collections.Generic;
 using System.Globalization;
-using System.Linq;
 using Xtensive.Collections;
 using Xtensive.Comparison;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/PagingProvider.cs b/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/PagingProvider.cs
index d917092ab..e23e169c7 100644
--- a/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/PagingProvider.cs
+++ b/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/PagingProvider.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2011.03.24
 
-using System;
 using System.Diagnostics;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/PredicateJoinProvider.cs b/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/PredicateJoinProvider.cs
index 2b24c1c3e..23d478cc4 100644
--- a/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/PredicateJoinProvider.cs
+++ b/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/PredicateJoinProvider.cs
@@ -4,10 +4,7 @@
 // Created by: Alexis Kochetov
 // Created:    2009.03.05
 
-using System;
-using System.Collections.Generic;
 using System.Diagnostics;
-using System.Linq;
 using System.Linq.Expressions;
 using Xtensive.Collections;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/RawProvider.cs b/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/RawProvider.cs
index 60a89bd07..75562f76a 100644
--- a/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/RawProvider.cs
+++ b/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/RawProvider.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Kochetov
 // Created:    2008.07.09
 
-using System;
-using System.Collections.Generic;
 using System.Linq.Expressions;
 using Xtensive.Collections;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/RowNumberProvider.cs b/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/RowNumberProvider.cs
index 257440ae8..35abdea2a 100644
--- a/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/RowNumberProvider.cs
+++ b/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/RowNumberProvider.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2009.03.05
 
-using System;
 using Xtensive.Collections;
 using Xtensive.Reflection;
 using Xtensive.Tuples.Transform;
diff --git a/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/SeekProvider.cs b/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/SeekProvider.cs
index 1b9c1a34d..cc5100874 100644
--- a/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/SeekProvider.cs
+++ b/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/SeekProvider.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kochetov
 // Created:    2008.08.14
 
-using System;
 using System.Linq.Expressions;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/SelectProvider.cs b/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/SelectProvider.cs
index 181e0054d..0587aad8a 100644
--- a/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/SelectProvider.cs
+++ b/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/SelectProvider.cs
@@ -4,10 +4,7 @@
 // Created by: Alexey Kochetov
 // Created:    2008.07.03
 
-using System;
-using System.Collections.Generic;
 using System.Diagnostics;
-using System.Linq;
 using Xtensive.Core;
 
 namespace Xtensive.Orm.Rse.Providers
diff --git a/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/SkipProvider.cs b/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/SkipProvider.cs
index 24a7a98d1..9ae4a3223 100644
--- a/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/SkipProvider.cs
+++ b/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/SkipProvider.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kochetov
 // Created:    2008.08.11
 
-using System;
 using Xtensive.Core;
 
 namespace Xtensive.Orm.Rse.Providers
diff --git a/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/SortProvider.cs b/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/SortProvider.cs
index 101bed019..a2d7eb9c6 100644
--- a/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/SortProvider.cs
+++ b/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/SortProvider.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kochetov
 // Created:    2008.07.04
 
-using System;
 using Xtensive.Collections;
 
 namespace Xtensive.Orm.Rse.Providers
diff --git a/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/StoreProvider.cs b/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/StoreProvider.cs
index b5ec29d67..ce7c9b2e3 100644
--- a/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/StoreProvider.cs
+++ b/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/StoreProvider.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2008.09.05
 
-using System;
 using Xtensive.Core;
 
 namespace Xtensive.Orm.Rse.Providers
diff --git a/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/TagProvider.cs b/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/TagProvider.cs
index 059fa632b..d6e82dd80 100644
--- a/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/TagProvider.cs
+++ b/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/TagProvider.cs
@@ -4,7 +4,6 @@
 // Created by: Edgar Isajanyan
 // Created:    2021.09.13
 
-using System;
 using Xtensive.Core;
 
 
diff --git a/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/TakeProvider.cs b/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/TakeProvider.cs
index cddccbdf8..fd94a1f7a 100644
--- a/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/TakeProvider.cs
+++ b/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/TakeProvider.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kochetov
 // Created:    2008.08.11
 
-using System;
 using Xtensive.Core;
 
 namespace Xtensive.Orm.Rse.Providers
diff --git a/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/UnionProvider.cs b/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/UnionProvider.cs
index 9b48469b2..e3b9a30db 100644
--- a/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/UnionProvider.cs
+++ b/Orm/Xtensive.Orm/Orm/Rse/Providers/Compilable/UnionProvider.cs
@@ -4,12 +4,9 @@
 // Created by: Elena Vakhtina
 // Created:    2009.04.01
 
-using System;
-using System.Collections.Generic;
 using Xtensive.Collections;
 
 
-using System.Linq;
 
 namespace Xtensive.Orm.Rse.Providers
 {
diff --git a/Orm/Xtensive.Orm/Orm/Rse/Providers/CompilableProvider.cs b/Orm/Xtensive.Orm/Orm/Rse/Providers/CompilableProvider.cs
index 5d631a298..0d7bed178 100644
--- a/Orm/Xtensive.Orm/Orm/Rse/Providers/CompilableProvider.cs
+++ b/Orm/Xtensive.Orm/Orm/Rse/Providers/CompilableProvider.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Kochetov
 // Created:    2008.07.03
 
-using System;
-using System.Collections.Generic;
 
 namespace Xtensive.Orm.Rse.Providers
 {
diff --git a/Orm/Xtensive.Orm/Orm/Rse/Providers/CompilableProviderVisitor.cs b/Orm/Xtensive.Orm/Orm/Rse/Providers/CompilableProviderVisitor.cs
index ccdced8d7..4733a1338 100644
--- a/Orm/Xtensive.Orm/Orm/Rse/Providers/CompilableProviderVisitor.cs
+++ b/Orm/Xtensive.Orm/Orm/Rse/Providers/CompilableProviderVisitor.cs
@@ -4,9 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.02.10
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Linq.Expressions;
 using Xtensive.Collections;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Orm/Rse/Providers/EnumerationContext.cs b/Orm/Xtensive.Orm/Orm/Rse/Providers/EnumerationContext.cs
index 583ffba58..ac0709ee8 100644
--- a/Orm/Xtensive.Orm/Orm/Rse/Providers/EnumerationContext.cs
+++ b/Orm/Xtensive.Orm/Orm/Rse/Providers/EnumerationContext.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.07.16
 
-using System;
-using System.Collections.Generic;
 using Xtensive.Core;
 
 
diff --git a/Orm/Xtensive.Orm/Orm/Rse/Providers/EnumerationContextOptions.cs b/Orm/Xtensive.Orm/Orm/Rse/Providers/EnumerationContextOptions.cs
index e5fd6f9a8..5f8665527 100644
--- a/Orm/Xtensive.Orm/Orm/Rse/Providers/EnumerationContextOptions.cs
+++ b/Orm/Xtensive.Orm/Orm/Rse/Providers/EnumerationContextOptions.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.11.14
 
-using System;
-using System.Collections.Generic;
 
 namespace Xtensive.Orm.Rse.Providers
 {
diff --git a/Orm/Xtensive.Orm/Orm/Rse/Providers/Executable/ExecutableRawProvider.cs b/Orm/Xtensive.Orm/Orm/Rse/Providers/Executable/ExecutableRawProvider.cs
index a449e2cde..72e5fff76 100644
--- a/Orm/Xtensive.Orm/Orm/Rse/Providers/Executable/ExecutableRawProvider.cs
+++ b/Orm/Xtensive.Orm/Orm/Rse/Providers/Executable/ExecutableRawProvider.cs
@@ -4,10 +4,6 @@
 // Created by: Alexey Kochetov
 // Created:    2008.05.08
 
-using System;
-using System.Collections.Generic;
-using System.Threading;
-using System.Threading.Tasks;
 using Xtensive.Orm.Providers;
 using Tuple = Xtensive.Tuples.Tuple;
 
diff --git a/Orm/Xtensive.Orm/Orm/Rse/Providers/ExecutableProvider.cs b/Orm/Xtensive.Orm/Orm/Rse/Providers/ExecutableProvider.cs
index 3fdfd41e4..3e3d184ed 100644
--- a/Orm/Xtensive.Orm/Orm/Rse/Providers/ExecutableProvider.cs
+++ b/Orm/Xtensive.Orm/Orm/Rse/Providers/ExecutableProvider.cs
@@ -4,10 +4,6 @@
 // Created by: Alexey Kochetov
 // Created:    2008.07.07
 
-using System;
-using System.Collections.Generic;
-using System.Threading;
-using System.Threading.Tasks;
 using Xtensive.Core;
 using Xtensive.Orm.Providers;
 using Tuple = Xtensive.Tuples.Tuple;
diff --git a/Orm/Xtensive.Orm/Orm/Rse/Providers/ExecutableProvider{TOrigin}.cs b/Orm/Xtensive.Orm/Orm/Rse/Providers/ExecutableProvider{TOrigin}.cs
index 585b9648c..77342a143 100644
--- a/Orm/Xtensive.Orm/Orm/Rse/Providers/ExecutableProvider{TOrigin}.cs
+++ b/Orm/Xtensive.Orm/Orm/Rse/Providers/ExecutableProvider{TOrigin}.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.08.13
 
-using System;
 
 
 namespace Xtensive.Orm.Rse.Providers
diff --git a/Orm/Xtensive.Orm/Orm/Rse/Providers/Provider.cs b/Orm/Xtensive.Orm/Orm/Rse/Providers/Provider.cs
index abab50d87..9a52ce7a6 100644
--- a/Orm/Xtensive.Orm/Orm/Rse/Providers/Provider.cs
+++ b/Orm/Xtensive.Orm/Orm/Rse/Providers/Provider.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Kochetov
 // Created:    2008.07.03
 
-using System;
-using System.Collections.Generic;
 using System.Diagnostics;
 using System.Text;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Orm/Rse/Providers/ProviderVisitor.cs b/Orm/Xtensive.Orm/Orm/Rse/Providers/ProviderVisitor.cs
index bb6f7f51f..d03e16539 100644
--- a/Orm/Xtensive.Orm/Orm/Rse/Providers/ProviderVisitor.cs
+++ b/Orm/Xtensive.Orm/Orm/Rse/Providers/ProviderVisitor.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.02.10
 
-using System;
 
 
 namespace Xtensive.Orm.Rse.Providers
diff --git a/Orm/Xtensive.Orm/Orm/Rse/Providers/TagScope.cs b/Orm/Xtensive.Orm/Orm/Rse/Providers/TagScope.cs
index e6a1f28bc..3d5edf5a3 100755
--- a/Orm/Xtensive.Orm/Orm/Rse/Providers/TagScope.cs
+++ b/Orm/Xtensive.Orm/Orm/Rse/Providers/TagScope.cs
@@ -2,8 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Collections.Generic;
 using Xtensive.Core;
 
 namespace Xtensive.Orm.Rse.Providers
diff --git a/Orm/Xtensive.Orm/Orm/Rse/RecordSetHeader.cs b/Orm/Xtensive.Orm/Orm/Rse/RecordSetHeader.cs
index d73985a44..3965e2608 100644
--- a/Orm/Xtensive.Orm/Orm/Rse/RecordSetHeader.cs
+++ b/Orm/Xtensive.Orm/Orm/Rse/RecordSetHeader.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Kochetov
 // Created:    2007.09.13
 
-using System;
-using System.Collections.Generic;
 using Xtensive.Collections;
 using Xtensive.Core;
 
@@ -13,7 +11,6 @@
 using Xtensive.Orm.Rse.Providers;
 using Xtensive.Tuples;
 using Tuple = Xtensive.Tuples.Tuple;
-using System.Linq;
 using IndexInfo = Xtensive.Orm.Model.IndexInfo;
 
 namespace Xtensive.Orm.Rse
diff --git a/Orm/Xtensive.Orm/Orm/Rse/RecordSetReader.cs b/Orm/Xtensive.Orm/Orm/Rse/RecordSetReader.cs
index dc33df8e5..e1dabd7fa 100644
--- a/Orm/Xtensive.Orm/Orm/Rse/RecordSetReader.cs
+++ b/Orm/Xtensive.Orm/Orm/Rse/RecordSetReader.cs
@@ -2,11 +2,7 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
-using System.Threading;
-using System.Threading.Tasks;
 using Xtensive.Orm.Providers;
 using Xtensive.Orm.Rse.Providers;
 using EnumerationContext = Xtensive.Orm.Rse.Providers.EnumerationContext;
diff --git a/Orm/Xtensive.Orm/Orm/Rse/RecordSetReaderExtensions.cs b/Orm/Xtensive.Orm/Orm/Rse/RecordSetReaderExtensions.cs
index 1635098c8..081d19060 100644
--- a/Orm/Xtensive.Orm/Orm/Rse/RecordSetReaderExtensions.cs
+++ b/Orm/Xtensive.Orm/Orm/Rse/RecordSetReaderExtensions.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Kochetov
 // Created:    2008.06.09
 
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Core;
 using EnumerationContext = Xtensive.Orm.Providers.EnumerationContext;
 using Tuple = Xtensive.Tuples.Tuple;
diff --git a/Orm/Xtensive.Orm/Orm/Rse/SystemColumn.cs b/Orm/Xtensive.Orm/Orm/Rse/SystemColumn.cs
index 95c1a744e..da38fd1b9 100644
--- a/Orm/Xtensive.Orm/Orm/Rse/SystemColumn.cs
+++ b/Orm/Xtensive.Orm/Orm/Rse/SystemColumn.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2009.03.05
 
-using System;
 
 
 namespace Xtensive.Orm.Rse
diff --git a/Orm/Xtensive.Orm/Orm/Rse/Transformation/ApplyProviderCorrector.cs b/Orm/Xtensive.Orm/Orm/Rse/Transformation/ApplyProviderCorrector.cs
index d7061d222..cda18d4bf 100644
--- a/Orm/Xtensive.Orm/Orm/Rse/Transformation/ApplyProviderCorrector.cs
+++ b/Orm/Xtensive.Orm/Orm/Rse/Transformation/ApplyProviderCorrector.cs
@@ -4,7 +4,6 @@
 // Created by: Alexander Nikolaev
 // Created:    2009.05.15
 
-using System;
 using Xtensive.Orm.Rse.Compilation;
 using Xtensive.Orm.Rse.Providers;
 
diff --git a/Orm/Xtensive.Orm/Orm/Rse/Transformation/ColumnMappingInspector.cs b/Orm/Xtensive.Orm/Orm/Rse/Transformation/ColumnMappingInspector.cs
index 23538116f..9a22f0d0b 100644
--- a/Orm/Xtensive.Orm/Orm/Rse/Transformation/ColumnMappingInspector.cs
+++ b/Orm/Xtensive.Orm/Orm/Rse/Transformation/ColumnMappingInspector.cs
@@ -2,9 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Linq.Expressions;
 using Xtensive.Collections;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Orm/Rse/Transformation/Internals/ApplyFilterRewriter.cs b/Orm/Xtensive.Orm/Orm/Rse/Transformation/Internals/ApplyFilterRewriter.cs
index bf68c109e..ffdb178b6 100644
--- a/Orm/Xtensive.Orm/Orm/Rse/Transformation/Internals/ApplyFilterRewriter.cs
+++ b/Orm/Xtensive.Orm/Orm/Rse/Transformation/Internals/ApplyFilterRewriter.cs
@@ -4,8 +4,6 @@
 // Created by: Alexander Nikolaev
 // Created:    2009.05.15
 
-using System;
-using System.Linq;
 using System.Linq.Expressions;
 using Xtensive.Core;
 using Xtensive.Linq;
diff --git a/Orm/Xtensive.Orm/Orm/Rse/Transformation/Internals/ApplyParameterSearcher.cs b/Orm/Xtensive.Orm/Orm/Rse/Transformation/Internals/ApplyParameterSearcher.cs
index 72c7beae3..641828cc8 100644
--- a/Orm/Xtensive.Orm/Orm/Rse/Transformation/Internals/ApplyParameterSearcher.cs
+++ b/Orm/Xtensive.Orm/Orm/Rse/Transformation/Internals/ApplyParameterSearcher.cs
@@ -4,7 +4,6 @@
 // Created by: Alexander Nikolaev
 // Created:    2009.05.15
 
-using System;
 using System.Linq.Expressions;
 using Xtensive.Core;
 using ExpressionVisitor = Xtensive.Linq.ExpressionVisitor;
diff --git a/Orm/Xtensive.Orm/Orm/Rse/Transformation/Internals/ApplyPredicateCollector.cs b/Orm/Xtensive.Orm/Orm/Rse/Transformation/Internals/ApplyPredicateCollector.cs
index 5c04bd3bc..38719fdc1 100644
--- a/Orm/Xtensive.Orm/Orm/Rse/Transformation/Internals/ApplyPredicateCollector.cs
+++ b/Orm/Xtensive.Orm/Orm/Rse/Transformation/Internals/ApplyPredicateCollector.cs
@@ -4,9 +4,6 @@
 // Created by: Alexander Nikolaev
 // Created:    2009.05.22
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Linq.Expressions;
 using Xtensive.Core;
 using Xtensive.Orm.Rse.Providers;
diff --git a/Orm/Xtensive.Orm/Orm/Rse/Transformation/Internals/ApplyProviderCorrectorRewriter.cs b/Orm/Xtensive.Orm/Orm/Rse/Transformation/Internals/ApplyProviderCorrectorRewriter.cs
index fd6084f9f..af9ee5415 100644
--- a/Orm/Xtensive.Orm/Orm/Rse/Transformation/Internals/ApplyProviderCorrectorRewriter.cs
+++ b/Orm/Xtensive.Orm/Orm/Rse/Transformation/Internals/ApplyProviderCorrectorRewriter.cs
@@ -4,9 +4,6 @@
 // Created by: Alexander Nikolaev
 // Created:    2009.05.15
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Linq.Expressions;
 using System.Text;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Orm/Rse/Transformation/Internals/CalculateProviderCollector.cs b/Orm/Xtensive.Orm/Orm/Rse/Transformation/Internals/CalculateProviderCollector.cs
index 352b1eedf..6a031976d 100644
--- a/Orm/Xtensive.Orm/Orm/Rse/Transformation/Internals/CalculateProviderCollector.cs
+++ b/Orm/Xtensive.Orm/Orm/Rse/Transformation/Internals/CalculateProviderCollector.cs
@@ -4,9 +4,6 @@
 // Created by: Alexander Nikolaev
 // Created:    2009.05.22
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Linq.Expressions;
 using Xtensive.Core;
 using Xtensive.Orm.Rse.Providers;
diff --git a/Orm/Xtensive.Orm/Orm/Rse/Transformation/Internals/CalculateRelatedExpressionRewriter.cs b/Orm/Xtensive.Orm/Orm/Rse/Transformation/Internals/CalculateRelatedExpressionRewriter.cs
index 5d082bd80..acf114b24 100644
--- a/Orm/Xtensive.Orm/Orm/Rse/Transformation/Internals/CalculateRelatedExpressionRewriter.cs
+++ b/Orm/Xtensive.Orm/Orm/Rse/Transformation/Internals/CalculateRelatedExpressionRewriter.cs
@@ -4,7 +4,6 @@
 // Created by: Alexander Nikolaev
 // Created:    2009.05.21
 
-using System.Linq;
 using System.Linq.Expressions;
 using Xtensive.Core;
 using Xtensive.Orm.Internals;
diff --git a/Orm/Xtensive.Orm/Orm/Rse/Transformation/Internals/CollectorHelper.cs b/Orm/Xtensive.Orm/Orm/Rse/Transformation/Internals/CollectorHelper.cs
index b949a8824..9f0b67157 100644
--- a/Orm/Xtensive.Orm/Orm/Rse/Transformation/Internals/CollectorHelper.cs
+++ b/Orm/Xtensive.Orm/Orm/Rse/Transformation/Internals/CollectorHelper.cs
@@ -4,9 +4,6 @@
 // Created by: Alexander Nikolaev
 // Created:    2009.05.22
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Linq.Expressions;
 using Xtensive.Core;
 using Xtensive.Linq;
diff --git a/Orm/Xtensive.Orm/Orm/Rse/Transformation/Internals/OrderingRewriter.cs b/Orm/Xtensive.Orm/Orm/Rse/Transformation/Internals/OrderingRewriter.cs
index 97d2c9e02..b6dae24c6 100644
--- a/Orm/Xtensive.Orm/Orm/Rse/Transformation/Internals/OrderingRewriter.cs
+++ b/Orm/Xtensive.Orm/Orm/Rse/Transformation/Internals/OrderingRewriter.cs
@@ -4,12 +4,9 @@
 // Created by: Alexander Nikolaev
 // Created:    2009.04.24
 
-using System;
-using System.Collections.Generic;
 using Xtensive.Core;
 using Xtensive.Collections;
 using Xtensive.Orm.Rse.Providers;
-using System.Linq;
 
 namespace Xtensive.Orm.Rse.Transformation
 {
diff --git a/Orm/Xtensive.Orm/Orm/Rse/Transformation/Internals/SkipTakeRewriter.cs b/Orm/Xtensive.Orm/Orm/Rse/Transformation/Internals/SkipTakeRewriter.cs
index 851a86aa0..c9d209b39 100644
--- a/Orm/Xtensive.Orm/Orm/Rse/Transformation/Internals/SkipTakeRewriter.cs
+++ b/Orm/Xtensive.Orm/Orm/Rse/Transformation/Internals/SkipTakeRewriter.cs
@@ -4,8 +4,6 @@
 // Created by: Elena Vakhtina
 // Created:    2009.04.24
 
-using System;
-using System.Linq;
 using System.Linq.Expressions;
 using Xtensive.Core;
 using Xtensive.Orm.Rse.Providers;
diff --git a/Orm/Xtensive.Orm/Orm/Rse/Transformation/Internals/SkipTakeRewriterState.cs b/Orm/Xtensive.Orm/Orm/Rse/Transformation/Internals/SkipTakeRewriterState.cs
index f9fb0b85c..a9a09c4c8 100644
--- a/Orm/Xtensive.Orm/Orm/Rse/Transformation/Internals/SkipTakeRewriterState.cs
+++ b/Orm/Xtensive.Orm/Orm/Rse/Transformation/Internals/SkipTakeRewriterState.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2010.01.21
 
-using System;
 using Xtensive.Core;
 
 namespace Xtensive.Orm.Rse.Transformation
diff --git a/Orm/Xtensive.Orm/Orm/Rse/Transformation/OrderingCorrector.cs b/Orm/Xtensive.Orm/Orm/Rse/Transformation/OrderingCorrector.cs
index 0314b07a6..3405d6d4d 100644
--- a/Orm/Xtensive.Orm/Orm/Rse/Transformation/OrderingCorrector.cs
+++ b/Orm/Xtensive.Orm/Orm/Rse/Transformation/OrderingCorrector.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.03.30
 
-using System;
 using Xtensive.Core;
 
 using Xtensive.Orm.Rse.Compilation;
diff --git a/Orm/Xtensive.Orm/Orm/Rse/Transformation/ProviderOrderingDescriptor.cs b/Orm/Xtensive.Orm/Orm/Rse/Transformation/ProviderOrderingDescriptor.cs
index b15b96d4e..c1fc020b7 100644
--- a/Orm/Xtensive.Orm/Orm/Rse/Transformation/ProviderOrderingDescriptor.cs
+++ b/Orm/Xtensive.Orm/Orm/Rse/Transformation/ProviderOrderingDescriptor.cs
@@ -4,7 +4,6 @@
 // Created by: Alexander Nikolaev
 // Created:    2009.04.24
 
-using System;
 
 using Xtensive.Orm.Rse.Providers;
 
diff --git a/Orm/Xtensive.Orm/Orm/Rse/Transformation/RedundantColumnOptimizer.cs b/Orm/Xtensive.Orm/Orm/Rse/Transformation/RedundantColumnOptimizer.cs
index 69667830e..8039dba2b 100644
--- a/Orm/Xtensive.Orm/Orm/Rse/Transformation/RedundantColumnOptimizer.cs
+++ b/Orm/Xtensive.Orm/Orm/Rse/Transformation/RedundantColumnOptimizer.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2009.10.12
 
-using System;
 using Xtensive.Orm.Rse.Compilation;
 using Xtensive.Orm.Rse.Providers;
 
diff --git a/Orm/Xtensive.Orm/Orm/Rse/Transformation/RedundantColumnRemover.cs b/Orm/Xtensive.Orm/Orm/Rse/Transformation/RedundantColumnRemover.cs
index fd96fd790..34d5b7af9 100644
--- a/Orm/Xtensive.Orm/Orm/Rse/Transformation/RedundantColumnRemover.cs
+++ b/Orm/Xtensive.Orm/Orm/Rse/Transformation/RedundantColumnRemover.cs
@@ -4,9 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2009.10.12
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Linq.Expressions;
 using System.Reflection;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Orm/Rse/Transformation/SkipTakeCorrector.cs b/Orm/Xtensive.Orm/Orm/Rse/Transformation/SkipTakeCorrector.cs
index 47ab3e89a..55a2277f0 100644
--- a/Orm/Xtensive.Orm/Orm/Rse/Transformation/SkipTakeCorrector.cs
+++ b/Orm/Xtensive.Orm/Orm/Rse/Transformation/SkipTakeCorrector.cs
@@ -4,7 +4,6 @@
 // Created by: Elena Vakhtina
 // Created:    2009.04.24
 
-using System;
 using Xtensive.Orm.Rse.Compilation;
 using Xtensive.Orm.Rse.Providers;
 
diff --git a/Orm/Xtensive.Orm/Orm/Rse/Transformation/TupleAccessGatherer.cs b/Orm/Xtensive.Orm/Orm/Rse/Transformation/TupleAccessGatherer.cs
index 7442886e8..ffe47a313 100644
--- a/Orm/Xtensive.Orm/Orm/Rse/Transformation/TupleAccessGatherer.cs
+++ b/Orm/Xtensive.Orm/Orm/Rse/Transformation/TupleAccessGatherer.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.04.17
 
-using System;
-using System.Collections.Generic;
 using System.Linq.Expressions;
 using Xtensive.Core;
 using ExpressionVisitor = Xtensive.Linq.ExpressionVisitor;
diff --git a/Orm/Xtensive.Orm/Orm/Rse/Transformation/TupleAccessRewriter.cs b/Orm/Xtensive.Orm/Orm/Rse/Transformation/TupleAccessRewriter.cs
index d0b00e565..b25d2fbc0 100644
--- a/Orm/Xtensive.Orm/Orm/Rse/Transformation/TupleAccessRewriter.cs
+++ b/Orm/Xtensive.Orm/Orm/Rse/Transformation/TupleAccessRewriter.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.04.17
 
-using System;
-using System.Collections.Generic;
 using System.Linq.Expressions;
 using Xtensive.Core;
 using ExpressionVisitor = Xtensive.Linq.ExpressionVisitor;
diff --git a/Orm/Xtensive.Orm/Orm/Rse/TupleExpressionExtensions.cs b/Orm/Xtensive.Orm/Orm/Rse/TupleExpressionExtensions.cs
index 8bae77d40..dd31d2eff 100644
--- a/Orm/Xtensive.Orm/Orm/Rse/TupleExpressionExtensions.cs
+++ b/Orm/Xtensive.Orm/Orm/Rse/TupleExpressionExtensions.cs
@@ -4,9 +4,6 @@
 // Created by: Elena Vakhtina
 // Created:    2009.03.20
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Linq.Expressions;
 using Xtensive.Core;
 using Xtensive.Linq;
diff --git a/Orm/Xtensive.Orm/Orm/Serialization/DeserializationContext.cs b/Orm/Xtensive.Orm/Orm/Serialization/DeserializationContext.cs
index 4175d724f..c6bbf1c69 100644
--- a/Orm/Xtensive.Orm/Orm/Serialization/DeserializationContext.cs
+++ b/Orm/Xtensive.Orm/Orm/Serialization/DeserializationContext.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Kofman
 // Created:    2009.03.30
 
-using System;
-using System.Collections.Generic;
 using System.Runtime.Serialization;
 using Xtensive.Core;
 using Xtensive.IoC;
diff --git a/Orm/Xtensive.Orm/Orm/Serialization/EntityReference.cs b/Orm/Xtensive.Orm/Orm/Serialization/EntityReference.cs
index 7593b65ad..deb7967c1 100644
--- a/Orm/Xtensive.Orm/Orm/Serialization/EntityReference.cs
+++ b/Orm/Xtensive.Orm/Orm/Serialization/EntityReference.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Kofman
 // Created:    2009.03.18
 
-using System;
 using System.Runtime.Serialization;
 using System.Security;
 using System.Security.Permissions;
diff --git a/Orm/Xtensive.Orm/Orm/Serialization/SerializationContext.cs b/Orm/Xtensive.Orm/Orm/Serialization/SerializationContext.cs
index d09b3818c..386f31acf 100644
--- a/Orm/Xtensive.Orm/Orm/Serialization/SerializationContext.cs
+++ b/Orm/Xtensive.Orm/Orm/Serialization/SerializationContext.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Kofman
 // Created:    2009.03.18
 
-using System;
 using System.Runtime.Serialization;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Orm/Serialization/SerializationHelper.cs b/Orm/Xtensive.Orm/Orm/Serialization/SerializationHelper.cs
index ce46e97f6..10815bd66 100644
--- a/Orm/Xtensive.Orm/Orm/Serialization/SerializationHelper.cs
+++ b/Orm/Xtensive.Orm/Orm/Serialization/SerializationHelper.cs
@@ -4,15 +4,12 @@
 // Created by: Alex Kofman
 // Created:    2009.03.24
 
-using System;
-using System.Collections.Generic;
 using System.Runtime.Serialization;
 using System.Security;
 using Xtensive.Core;
 using Xtensive.Orm.Model;
 using Xtensive.Tuples;
 using Tuple = Xtensive.Tuples.Tuple;
-using System.Linq;
 
 namespace Xtensive.Orm.Serialization
 {
diff --git a/Orm/Xtensive.Orm/Orm/Services/DirectEntityAccessor.cs b/Orm/Xtensive.Orm/Orm/Services/DirectEntityAccessor.cs
index d863a2c4a..9d31ffce8 100644
--- a/Orm/Xtensive.Orm/Orm/Services/DirectEntityAccessor.cs
+++ b/Orm/Xtensive.Orm/Orm/Services/DirectEntityAccessor.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2008.11.02
 
-using System;
 using Xtensive.Core;
 using Xtensive.IoC;
 using Xtensive.Orm.Model;
diff --git a/Orm/Xtensive.Orm/Orm/Services/DirectEntitySetAccessor.cs b/Orm/Xtensive.Orm/Orm/Services/DirectEntitySetAccessor.cs
index 317ca24e2..941b53f1e 100644
--- a/Orm/Xtensive.Orm/Orm/Services/DirectEntitySetAccessor.cs
+++ b/Orm/Xtensive.Orm/Orm/Services/DirectEntitySetAccessor.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2008.11.06
 
-using System;
 using Xtensive.Core;
 
 using Xtensive.IoC;
diff --git a/Orm/Xtensive.Orm/Orm/Services/DirectPersistentAccessor.cs b/Orm/Xtensive.Orm/Orm/Services/DirectPersistentAccessor.cs
index 5aa8ab947..b2186cb02 100644
--- a/Orm/Xtensive.Orm/Orm/Services/DirectPersistentAccessor.cs
+++ b/Orm/Xtensive.Orm/Orm/Services/DirectPersistentAccessor.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2008.11.02
 
-using System;
 using Xtensive.Core;
 using Xtensive.IoC;
 using Xtensive.Orm.Internals;
diff --git a/Orm/Xtensive.Orm/Orm/Services/DirectSessionAccessor.cs b/Orm/Xtensive.Orm/Orm/Services/DirectSessionAccessor.cs
index 0d5e11527..f85aaaa25 100644
--- a/Orm/Xtensive.Orm/Orm/Services/DirectSessionAccessor.cs
+++ b/Orm/Xtensive.Orm/Orm/Services/DirectSessionAccessor.cs
@@ -4,8 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2008.11.05
 
-using System;
-using System.Collections.Generic;
 using Xtensive.Core;
 using Xtensive.IoC;
 using Xtensive.Orm.Internals;
diff --git a/Orm/Xtensive.Orm/Orm/Services/Old/EntitySetStateAccessor.cs b/Orm/Xtensive.Orm/Orm/Services/Old/EntitySetStateAccessor.cs
index 667aa9063..50de2f4c4 100644
--- a/Orm/Xtensive.Orm/Orm/Services/Old/EntitySetStateAccessor.cs
+++ b/Orm/Xtensive.Orm/Orm/Services/Old/EntitySetStateAccessor.cs
@@ -5,9 +5,7 @@
 // Created:    2009.12.18
 
 using System.Collections;
-using System.Collections.Generic;
 using System.Diagnostics;
-using System.Linq;
 using Xtensive.Collections;
 
 namespace Xtensive.Orm.Services
diff --git a/Orm/Xtensive.Orm/Orm/Services/Old/PersistentStateAccessor.cs b/Orm/Xtensive.Orm/Orm/Services/Old/PersistentStateAccessor.cs
index e8134a788..523082193 100644
--- a/Orm/Xtensive.Orm/Orm/Services/Old/PersistentStateAccessor.cs
+++ b/Orm/Xtensive.Orm/Orm/Services/Old/PersistentStateAccessor.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2009.12.31
 
-using System;
 using Xtensive.Orm.Model;
 
 namespace Xtensive.Orm.Services
diff --git a/Orm/Xtensive.Orm/Orm/Services/Old/SessionStateAccessor.cs b/Orm/Xtensive.Orm/Orm/Services/Old/SessionStateAccessor.cs
index 6af7c6e41..c64b8f6af 100644
--- a/Orm/Xtensive.Orm/Orm/Services/Old/SessionStateAccessor.cs
+++ b/Orm/Xtensive.Orm/Orm/Services/Old/SessionStateAccessor.cs
@@ -4,11 +4,8 @@
 // Created by: Alex Yakunin
 // Created:    2009.12.18
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
 using System.Diagnostics;
-using System.Linq;
 using Xtensive.Caching;
 
 namespace Xtensive.Orm.Services
diff --git a/Orm/Xtensive.Orm/Orm/Services/QueryBuilding/QueryBuilder.cs b/Orm/Xtensive.Orm/Orm/Services/QueryBuilding/QueryBuilder.cs
index 59b1811e6..83afb85c4 100644
--- a/Orm/Xtensive.Orm/Orm/Services/QueryBuilding/QueryBuilder.cs
+++ b/Orm/Xtensive.Orm/Orm/Services/QueryBuilding/QueryBuilder.cs
@@ -4,9 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.02.26
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Core;
 using Xtensive.IoC;
 using Xtensive.Orm.Linq;
diff --git a/Orm/Xtensive.Orm/Orm/Services/QueryBuilding/QueryCommand.cs b/Orm/Xtensive.Orm/Orm/Services/QueryBuilding/QueryCommand.cs
index 443876580..d8fc6b22e 100644
--- a/Orm/Xtensive.Orm/Orm/Services/QueryBuilding/QueryCommand.cs
+++ b/Orm/Xtensive.Orm/Orm/Services/QueryBuilding/QueryCommand.cs
@@ -4,11 +4,8 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.02.27
 
-using System;
 using System.Data.Common;
 using System.Runtime.CompilerServices;
-using System.Threading;
-using System.Threading.Tasks;
 using Xtensive.Orm.Providers;
 
 namespace Xtensive.Orm.Services
diff --git a/Orm/Xtensive.Orm/Orm/Services/QueryBuilding/QueryParameterBinding.cs b/Orm/Xtensive.Orm/Orm/Services/QueryBuilding/QueryParameterBinding.cs
index b70f74c9f..bd739bc30 100644
--- a/Orm/Xtensive.Orm/Orm/Services/QueryBuilding/QueryParameterBinding.cs
+++ b/Orm/Xtensive.Orm/Orm/Services/QueryBuilding/QueryParameterBinding.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.02.26
 
-using System;
 using Xtensive.Core;
 using Xtensive.Sql.Dml;
 
diff --git a/Orm/Xtensive.Orm/Orm/Services/QueryBuilding/QueryRequest.cs b/Orm/Xtensive.Orm/Orm/Services/QueryBuilding/QueryRequest.cs
index 54d542db1..f08885553 100644
--- a/Orm/Xtensive.Orm/Orm/Services/QueryBuilding/QueryRequest.cs
+++ b/Orm/Xtensive.Orm/Orm/Services/QueryBuilding/QueryRequest.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.02.26
 
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Orm.Providers;
 using Xtensive.Sql.Compiler;
 
diff --git a/Orm/Xtensive.Orm/Orm/Services/QueryBuilding/QueryTranslationResult.cs b/Orm/Xtensive.Orm/Orm/Services/QueryBuilding/QueryTranslationResult.cs
index 891f318fa..cb5f17a44 100644
--- a/Orm/Xtensive.Orm/Orm/Services/QueryBuilding/QueryTranslationResult.cs
+++ b/Orm/Xtensive.Orm/Orm/Services/QueryBuilding/QueryTranslationResult.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.02.27
 
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Sql;
 using Xtensive.Sql.Dml;
 
diff --git a/Orm/Xtensive.Orm/Orm/Services/QueryFormatter.cs b/Orm/Xtensive.Orm/Orm/Services/QueryFormatter.cs
index 2218ea6cc..ffaa0ebce 100644
--- a/Orm/Xtensive.Orm/Orm/Services/QueryFormatter.cs
+++ b/Orm/Xtensive.Orm/Orm/Services/QueryFormatter.cs
@@ -4,9 +4,7 @@
 // Created by: Dmitri Maximov
 // Created:    2011.03.02
 
-using System.Collections.Generic;
 using System.Data.Common;
-using System.Linq;
 using Xtensive.Core;
 using Xtensive.IoC;
 using Xtensive.Orm.Providers;
diff --git a/Orm/Xtensive.Orm/Orm/Services/TransactionMonitor.cs b/Orm/Xtensive.Orm/Orm/Services/TransactionMonitor.cs
index f440c246f..ec1359dc0 100644
--- a/Orm/Xtensive.Orm/Orm/Services/TransactionMonitor.cs
+++ b/Orm/Xtensive.Orm/Orm/Services/TransactionMonitor.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2010.11.26
 
-using System;
-using System.Collections.Generic;
 using Xtensive.Collections;
 
 using Xtensive.IoC;
diff --git a/Orm/Xtensive.Orm/Orm/Session.Cache.cs b/Orm/Xtensive.Orm/Orm/Session.Cache.cs
index 4e51c6066..308699000 100644
--- a/Orm/Xtensive.Orm/Orm/Session.Cache.cs
+++ b/Orm/Xtensive.Orm/Orm/Session.Cache.cs
@@ -4,11 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.11.07
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Threading;
-using System.Threading.Tasks;
 using Xtensive.Caching;
 using Xtensive.Core;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm/Orm/Session.Events.cs b/Orm/Xtensive.Orm/Orm/Session.Events.cs
index 08b0ed2f3..b3a358335 100644
--- a/Orm/Xtensive.Orm/Orm/Session.Events.cs
+++ b/Orm/Xtensive.Orm/Orm/Session.Events.cs
@@ -4,13 +4,11 @@
 // Created by: Alexander Nikolaev
 // Created:    2009.06.29
 
-using System;
 using System.Collections.Specialized;
 using System.ComponentModel;
 using System.Transactions;
 using Xtensive.Orm.Model;
 using Xtensive.Orm.Operations;
-using System.Linq;
 using Xtensive.Core;
 
 namespace Xtensive.Orm
diff --git a/Orm/Xtensive.Orm/Orm/Session.Persist.cs b/Orm/Xtensive.Orm/Orm/Session.Persist.cs
index a8990861f..2eab13709 100644
--- a/Orm/Xtensive.Orm/Orm/Session.Persist.cs
+++ b/Orm/Xtensive.Orm/Orm/Session.Persist.cs
@@ -4,12 +4,8 @@
 // Created by: Dmitri Maximov
 // Created:    2007.08.10
 
-using System;
 using System.Transactions;
-using System.Linq;
 using System.Runtime.InteropServices.ComTypes;
-using System.Threading;
-using System.Threading.Tasks;
 using Xtensive.Core;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Internals;
diff --git a/Orm/Xtensive.Orm/Orm/Session.Query.cs b/Orm/Xtensive.Orm/Orm/Session.Query.cs
index 438b3370c..13397655a 100644
--- a/Orm/Xtensive.Orm/Orm/Session.Query.cs
+++ b/Orm/Xtensive.Orm/Orm/Session.Query.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2010.09.09
 
-using System;
 using Xtensive.Core;
 
 namespace Xtensive.Orm
diff --git a/Orm/Xtensive.Orm/Orm/Session.QueryTasks.cs b/Orm/Xtensive.Orm/Orm/Session.QueryTasks.cs
index ab51dbb90..121cabc06 100644
--- a/Orm/Xtensive.Orm/Orm/Session.QueryTasks.cs
+++ b/Orm/Xtensive.Orm/Orm/Session.QueryTasks.cs
@@ -4,10 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.10.09
 
-using System.Collections.Generic;
-using System.Linq;
-using System.Threading;
-using System.Threading.Tasks;
 using Xtensive.Orm.Internals;
 
 
diff --git a/Orm/Xtensive.Orm/Orm/Session.SystemLogic.cs b/Orm/Xtensive.Orm/Orm/Session.SystemLogic.cs
index a33e69beb..4bdd4f5d0 100644
--- a/Orm/Xtensive.Orm/Orm/Session.SystemLogic.cs
+++ b/Orm/Xtensive.Orm/Orm/Session.SystemLogic.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2010.08.03
 
-using System;
 using Xtensive.Core;
 
 namespace Xtensive.Orm
diff --git a/Orm/Xtensive.Orm/Orm/Session.Transactions.cs b/Orm/Xtensive.Orm/Orm/Session.Transactions.cs
index a68c035d0..7079bc155 100644
--- a/Orm/Xtensive.Orm/Orm/Session.Transactions.cs
+++ b/Orm/Xtensive.Orm/Orm/Session.Transactions.cs
@@ -4,10 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.11.07
 
-using System;
-using System.Collections.Generic;
-using System.Threading;
-using System.Threading.Tasks;
 using System.Transactions;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Internals;
diff --git a/Orm/Xtensive.Orm/Orm/Session.Validation.cs b/Orm/Xtensive.Orm/Orm/Session.Validation.cs
index 0e6cf4970..f237850ac 100644
--- a/Orm/Xtensive.Orm/Orm/Session.Validation.cs
+++ b/Orm/Xtensive.Orm/Orm/Session.Validation.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.11.07
 
-using System;
-using System.Collections.Generic;
 using Xtensive.Orm.Validation;
 
 namespace Xtensive.Orm
diff --git a/Orm/Xtensive.Orm/Orm/Session.cs b/Orm/Xtensive.Orm/Orm/Session.cs
index df4f33267..1517108e8 100644
--- a/Orm/Xtensive.Orm/Orm/Session.cs
+++ b/Orm/Xtensive.Orm/Orm/Session.cs
@@ -4,13 +4,8 @@
 // Created by: Dmitri Maximov
 // Created:    2007.08.10
 
-using System;
-using System.Collections.Generic;
 using System.Data;
 using System.Diagnostics;
-using System.Linq;
-using System.Threading;
-using System.Threading.Tasks;
 using JetBrains.Annotations;
 using Xtensive.Collections;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Orm/SessionBound.cs b/Orm/Xtensive.Orm/Orm/SessionBound.cs
index 87a3b2955..3ee6e65db 100644
--- a/Orm/Xtensive.Orm/Orm/SessionBound.cs
+++ b/Orm/Xtensive.Orm/Orm/SessionBound.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2007.08.10
 
-using System;
 using System.Diagnostics;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Orm/SessionEventAccessor.cs b/Orm/Xtensive.Orm/Orm/SessionEventAccessor.cs
index 7dcc4ef38..6b4383fca 100644
--- a/Orm/Xtensive.Orm/Orm/SessionEventAccessor.cs
+++ b/Orm/Xtensive.Orm/Orm/SessionEventAccessor.cs
@@ -4,11 +4,9 @@
 // Created by: Alex Yakunin
 // Created:    2010.08.10
 
-using System;
 using System.Collections.Specialized;
 using System.ComponentModel;
 using System.Data.Common;
-using System.Linq;
 using System.Linq.Expressions;
 using Xtensive.Core;
 using Xtensive.Orm.Model;
diff --git a/Orm/Xtensive.Orm/Orm/SessionEventArgs.cs b/Orm/Xtensive.Orm/Orm/SessionEventArgs.cs
index 1e9bc355d..89894fd76 100644
--- a/Orm/Xtensive.Orm/Orm/SessionEventArgs.cs
+++ b/Orm/Xtensive.Orm/Orm/SessionEventArgs.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2009.06.04
 
-using System;
 
 
 namespace Xtensive.Orm
diff --git a/Orm/Xtensive.Orm/Orm/SessionScope.cs b/Orm/Xtensive.Orm/Orm/SessionScope.cs
index 43024817b..c7a3333be 100644
--- a/Orm/Xtensive.Orm/Orm/SessionScope.cs
+++ b/Orm/Xtensive.Orm/Orm/SessionScope.cs
@@ -4,8 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2007.08.29
 
-using System;
-using System.Threading;
 using Xtensive.Core;
 
 namespace Xtensive.Orm
diff --git a/Orm/Xtensive.Orm/Orm/StorageNode.cs b/Orm/Xtensive.Orm/Orm/StorageNode.cs
index 20ac4d09b..d41ca2633 100644
--- a/Orm/Xtensive.Orm/Orm/StorageNode.cs
+++ b/Orm/Xtensive.Orm/Orm/StorageNode.cs
@@ -4,11 +4,7 @@
 // Created by: Denis Krjuchkov
 // Created:    2014.03.13
 
-using System;
 using System.Collections.Concurrent;
-using System.Collections.Generic;
-using System.Threading;
-using System.Threading.Tasks;
 using Xtensive.Core;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Interfaces;
diff --git a/Orm/Xtensive.Orm/Orm/StorageNodeManager.cs b/Orm/Xtensive.Orm/Orm/StorageNodeManager.cs
index 8890797b5..c00fe5693 100644
--- a/Orm/Xtensive.Orm/Orm/StorageNodeManager.cs
+++ b/Orm/Xtensive.Orm/Orm/StorageNodeManager.cs
@@ -4,10 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2014.03.13
 
-using System;
-using System.Linq;
-using System.Threading;
-using System.Threading.Tasks;
 using JetBrains.Annotations;
 using Xtensive.Core;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm/Orm/Structure.cs b/Orm/Xtensive.Orm/Orm/Structure.cs
index 9b9108409..0dacf1544 100644
--- a/Orm/Xtensive.Orm/Orm/Structure.cs
+++ b/Orm/Xtensive.Orm/Orm/Structure.cs
@@ -4,10 +4,8 @@
 // Created by: Dmitri Maximov
 // Created:    2007.08.01
 
-using System;
 using System.ComponentModel;
 using System.Diagnostics;
-using System.Linq;
 using System.Runtime.Serialization;
 using Xtensive.Comparison;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Orm/TargetKind.cs b/Orm/Xtensive.Orm/Orm/TargetKind.cs
index a14ad4d60..e1860053e 100644
--- a/Orm/Xtensive.Orm/Orm/TargetKind.cs
+++ b/Orm/Xtensive.Orm/Orm/TargetKind.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.02.09
 
-using System;
 
 namespace Xtensive.Orm {
 
diff --git a/Orm/Xtensive.Orm/Orm/Transaction.cs b/Orm/Xtensive.Orm/Orm/Transaction.cs
index 60490b54f..0a527b9c4 100644
--- a/Orm/Xtensive.Orm/Orm/Transaction.cs
+++ b/Orm/Xtensive.Orm/Orm/Transaction.cs
@@ -4,11 +4,6 @@
 // Created by: Alex Kofman
 // Created:    2008.08.20
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Threading;
-using System.Threading.Tasks;
 using System.Transactions;
 using JetBrains.Annotations;
 using Xtensive.Collections;
diff --git a/Orm/Xtensive.Orm/Orm/TransactionEventArgs.cs b/Orm/Xtensive.Orm/Orm/TransactionEventArgs.cs
index d14ab74c9..a03638f04 100644
--- a/Orm/Xtensive.Orm/Orm/TransactionEventArgs.cs
+++ b/Orm/Xtensive.Orm/Orm/TransactionEventArgs.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2009.06.04
 
-using System;
 
 
 namespace Xtensive.Orm
diff --git a/Orm/Xtensive.Orm/Orm/TransactionScope.cs b/Orm/Xtensive.Orm/Orm/TransactionScope.cs
index 732f10f05..eb783bb63 100644
--- a/Orm/Xtensive.Orm/Orm/TransactionScope.cs
+++ b/Orm/Xtensive.Orm/Orm/TransactionScope.cs
@@ -4,8 +4,6 @@
 // Created by: 
 // Created:    2008.08.30
 
-using System;
-using System.Threading.Tasks;
 using Xtensive.Core;
 
 namespace Xtensive.Orm
diff --git a/Orm/Xtensive.Orm/Orm/TransactionState.cs b/Orm/Xtensive.Orm/Orm/TransactionState.cs
index d29eea03e..7e9158166 100644
--- a/Orm/Xtensive.Orm/Orm/TransactionState.cs
+++ b/Orm/Xtensive.Orm/Orm/TransactionState.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kochetov
 // Created:    2007.11.02
 
-using System;
 
 namespace Xtensive.Orm
 {
diff --git a/Orm/Xtensive.Orm/Orm/TransactionalExtensions.cs b/Orm/Xtensive.Orm/Orm/TransactionalExtensions.cs
index 2fc87f6ef..aaebd63e0 100644
--- a/Orm/Xtensive.Orm/Orm/TransactionalExtensions.cs
+++ b/Orm/Xtensive.Orm/Orm/TransactionalExtensions.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2009.07.31
 
-using System;
-using System.Collections.Generic;
 using System.Transactions;
 
 namespace Xtensive.Orm
diff --git a/Orm/Xtensive.Orm/Orm/TransactionalValue.cs b/Orm/Xtensive.Orm/Orm/TransactionalValue.cs
index aae98a3f4..8713ed5a8 100644
--- a/Orm/Xtensive.Orm/Orm/TransactionalValue.cs
+++ b/Orm/Xtensive.Orm/Orm/TransactionalValue.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2009.12.18
 
-using System;
 using Xtensive.Caching;
 
 
diff --git a/Orm/Xtensive.Orm/Orm/TypeReference.cs b/Orm/Xtensive.Orm/Orm/TypeReference.cs
index 93faa6d0f..a818a7bd3 100644
--- a/Orm/Xtensive.Orm/Orm/TypeReference.cs
+++ b/Orm/Xtensive.Orm/Orm/TypeReference.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2009.10.09
 
-using System;
 
 using Xtensive.Orm.Model;
 
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/Attributes/AssemblyInfoAttribute.cs b/Orm/Xtensive.Orm/Orm/Upgrade/Attributes/AssemblyInfoAttribute.cs
index fc357f60b..130a8bacd 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/Attributes/AssemblyInfoAttribute.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/Attributes/AssemblyInfoAttribute.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2009.04.30
 
-using System;
 
 
 namespace Xtensive.Orm.Upgrade
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/Attributes/RecycledAttribute.cs b/Orm/Xtensive.Orm/Orm/Upgrade/Attributes/RecycledAttribute.cs
index 38906a90e..e9e0921c5 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/Attributes/RecycledAttribute.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/Attributes/RecycledAttribute.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2009.04.30
 
-using System;
 
 
 namespace Xtensive.Orm.Upgrade
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/DomainUpgradeModeExtensions.cs b/Orm/Xtensive.Orm/Orm/Upgrade/DomainUpgradeModeExtensions.cs
index 2c5b3ac16..7d5f6642a 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/DomainUpgradeModeExtensions.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/DomainUpgradeModeExtensions.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2010.03.05
 
-using System;
 
 namespace Xtensive.Orm.Upgrade
 {
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/Hints/ChangeFieldTypeHint.cs b/Orm/Xtensive.Orm/Orm/Upgrade/Hints/ChangeFieldTypeHint.cs
index d13c307ff..d0071a1db 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/Hints/ChangeFieldTypeHint.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/Hints/ChangeFieldTypeHint.cs
@@ -4,8 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.06.05
 
-using System;
-using System.Collections.Generic;
 using System.Linq.Expressions;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/Hints/CopyFieldHint.cs b/Orm/Xtensive.Orm/Orm/Upgrade/Hints/CopyFieldHint.cs
index c05ac1f50..9555c98df 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/Hints/CopyFieldHint.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/Hints/CopyFieldHint.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Kryuchkov
 // Created:    2009.05.29
 
-using System;
 using System.Linq.Expressions;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/Hints/MergeTypeHint.cs b/Orm/Xtensive.Orm/Orm/Upgrade/Hints/MergeTypeHint.cs
index 676071109..d19085490 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/Hints/MergeTypeHint.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/Hints/MergeTypeHint.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Kofman
 // Created:    2009.04.29
 
-using System;
-using System.Collections.Generic;
 using System.Linq.Expressions;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/Hints/MoveFieldHint.cs b/Orm/Xtensive.Orm/Orm/Upgrade/Hints/MoveFieldHint.cs
index 22fb78d3f..0094b7537 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/Hints/MoveFieldHint.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/Hints/MoveFieldHint.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.10.14
 
-using System;
 using System.Diagnostics;
 using System.Linq.Expressions;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/Hints/RecycledTypeHint.cs b/Orm/Xtensive.Orm/Orm/Upgrade/Hints/RecycledTypeHint.cs
index 7152490fa..23811140f 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/Hints/RecycledTypeHint.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/Hints/RecycledTypeHint.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Kofman
 // Created:    2009.04.29
 
-using System;
-using System.Collections.Generic;
 using System.Linq.Expressions;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/Hints/RemoveFieldHint.cs b/Orm/Xtensive.Orm/Orm/Upgrade/Hints/RemoveFieldHint.cs
index 90413bb2c..4034b6f50 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/Hints/RemoveFieldHint.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/Hints/RemoveFieldHint.cs
@@ -4,8 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.10.09
 
-using System;
-using System.Collections.Generic;
 using System.Linq.Expressions;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/Hints/RemoveTypeHint.cs b/Orm/Xtensive.Orm/Orm/Upgrade/Hints/RemoveTypeHint.cs
index a922dadce..c78ec7158 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/Hints/RemoveTypeHint.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/Hints/RemoveTypeHint.cs
@@ -4,8 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.10.09
 
-using System;
-using System.Collections.Generic;
 using Xtensive.Core;
 
 
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/Hints/RenameFieldHint.cs b/Orm/Xtensive.Orm/Orm/Upgrade/Hints/RenameFieldHint.cs
index 76a75def7..c666dec2d 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/Hints/RenameFieldHint.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/Hints/RenameFieldHint.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Kofman
 // Created:    2009.04.29
 
-using System;
 using System.Linq.Expressions;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/Hints/RenameTypeHint.cs b/Orm/Xtensive.Orm/Orm/Upgrade/Hints/RenameTypeHint.cs
index a8288190a..2f3f458fb 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/Hints/RenameTypeHint.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/Hints/RenameTypeHint.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Kofman
 // Created:    2009.04.29
 
-using System;
 using Xtensive.Core;
 
 using Xtensive.Reflection;
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/Hints/UpgradeHint.cs b/Orm/Xtensive.Orm/Orm/Upgrade/Hints/UpgradeHint.cs
index 5b94bfe73..011c0d7b6 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/Hints/UpgradeHint.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/Hints/UpgradeHint.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Kofman
 // Created:    2009.04.29
 
-using System;
 
 namespace Xtensive.Orm.Upgrade
 {
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/Interfaces/IUpgradeHandler.cs b/Orm/Xtensive.Orm/Orm/Upgrade/Interfaces/IUpgradeHandler.cs
index c77d7885f..01c78edd1 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/Interfaces/IUpgradeHandler.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/Interfaces/IUpgradeHandler.cs
@@ -4,10 +4,7 @@
 // Created by: Alex Kofman
 // Created:    2009.04.08
 
-using System;
 using System.Reflection;
-using System.Threading;
-using System.Threading.Tasks;
 
 namespace Xtensive.Orm.Upgrade
 {
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/Internals/CatalogCloner.cs b/Orm/Xtensive.Orm/Orm/Upgrade/Internals/CatalogCloner.cs
index d59ef708b..cb1a22e0f 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/Internals/CatalogCloner.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/Internals/CatalogCloner.cs
@@ -4,9 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2016.10.20
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Core;
 using Xtensive.Orm.Providers;
 using Xtensive.Sql.Dml;
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/Internals/DomainExtractedModelBuilder.cs b/Orm/Xtensive.Orm/Orm/Upgrade/Internals/DomainExtractedModelBuilder.cs
index 542eba21c..6f8e270fd 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/Internals/DomainExtractedModelBuilder.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/Internals/DomainExtractedModelBuilder.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2016.02.23
 
-using System;
-using System.Linq;
 using Xtensive.Core;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Providers;
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/Internals/DomainModelConverter.cs b/Orm/Xtensive.Orm/Orm/Upgrade/Internals/DomainModelConverter.cs
index da8257834..0b4437c2f 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/Internals/DomainModelConverter.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/Internals/DomainModelConverter.cs
@@ -4,9 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.04.02
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Collections;
 using Xtensive.Core;
 using Xtensive.Modelling;
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/Internals/HintGenerationResult.cs b/Orm/Xtensive.Orm/Orm/Upgrade/Internals/HintGenerationResult.cs
index 9b819a93b..99e9b92c3 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/Internals/HintGenerationResult.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/Internals/HintGenerationResult.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.10.14
 
-using System.Collections.Generic;
 using Xtensive.Modelling.Comparison.Hints;
 
 namespace Xtensive.Orm.Upgrade
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/Internals/HintGenerator.cs b/Orm/Xtensive.Orm/Orm/Upgrade/Internals/HintGenerator.cs
index b13e86b85..286af757c 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/Internals/HintGenerator.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/Internals/HintGenerator.cs
@@ -4,9 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.06.04
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Collections;
 using Xtensive.Core;
 using Xtensive.Modelling.Comparison.Hints;
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/Internals/IgnoreRulesHandler.cs b/Orm/Xtensive.Orm/Orm/Upgrade/Internals/IgnoreRulesHandler.cs
index 3c86bce2d..40a974459 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/Internals/IgnoreRulesHandler.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/Internals/IgnoreRulesHandler.cs
@@ -4,9 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2013.08.20
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Core;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Providers;
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/Internals/Interfaces/IUpgradeHintsProcessor.cs b/Orm/Xtensive.Orm/Orm/Upgrade/Internals/Interfaces/IUpgradeHintsProcessor.cs
index f97c0acd9..98edaa78a 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/Internals/Interfaces/IUpgradeHintsProcessor.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/Internals/Interfaces/IUpgradeHintsProcessor.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2015.01.22
 
-using System.Collections.Generic;
 
 namespace Xtensive.Orm.Upgrade.Internals.Interfaces
 {
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/Internals/Metadata/MetadataExtractor.cs b/Orm/Xtensive.Orm/Orm/Upgrade/Internals/Metadata/MetadataExtractor.cs
index 90dc5eed2..2117f7209 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/Internals/Metadata/MetadataExtractor.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/Internals/Metadata/MetadataExtractor.cs
@@ -4,13 +4,8 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.02.16
 
-using System;
-using System.Collections.Generic;
 using System.Data;
 using System.Data.Common;
-using System.Linq;
-using System.Threading;
-using System.Threading.Tasks;
 using Xtensive.Core;
 using Xtensive.Orm.Providers;
 using Xtensive.Sql;
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/Internals/Metadata/MetadataMapping.cs b/Orm/Xtensive.Orm/Orm/Upgrade/Internals/Metadata/MetadataMapping.cs
index 724aeb79d..890518eca 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/Internals/Metadata/MetadataMapping.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/Internals/Metadata/MetadataMapping.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.03.22
 
-using System;
-using System.Linq;
 using System.Linq.Expressions;
 using Xtensive.Core;
 using Xtensive.Orm.Metadata;
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/Internals/Metadata/MetadataSet.cs b/Orm/Xtensive.Orm/Orm/Upgrade/Internals/Metadata/MetadataSet.cs
index 3b859cd7b..32dcc29da 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/Internals/Metadata/MetadataSet.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/Internals/Metadata/MetadataSet.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.03.22
 
-using System.Collections.Generic;
 
 namespace Xtensive.Orm.Upgrade
 {
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/Internals/Metadata/MetadataWriter.cs b/Orm/Xtensive.Orm/Orm/Upgrade/Internals/Metadata/MetadataWriter.cs
index 0dd9e741d..6d9a4bff8 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/Internals/Metadata/MetadataWriter.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/Internals/Metadata/MetadataWriter.cs
@@ -4,9 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.03.22
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Orm.Providers;
 using Xtensive.Reflection;
 using Xtensive.Sql;
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/Internals/NodeExtractedModelBuilder.cs b/Orm/Xtensive.Orm/Orm/Upgrade/Internals/NodeExtractedModelBuilder.cs
index 2096b8da4..711766878 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/Internals/NodeExtractedModelBuilder.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/Internals/NodeExtractedModelBuilder.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2016.02.23
 
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Core;
 using Xtensive.Orm.Configuration;
 using Xtensive.Orm.Providers;
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/Internals/NullUpgradeHintsProcessor.cs b/Orm/Xtensive.Orm/Orm/Upgrade/Internals/NullUpgradeHintsProcessor.cs
index 5ec0f40bd..efc226f08 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/Internals/NullUpgradeHintsProcessor.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/Internals/NullUpgradeHintsProcessor.cs
@@ -4,9 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2015.01.22
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Collections;
 using Xtensive.Core;
 using Xtensive.Orm.Model.Stored;
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/Internals/PartialIndexInfoMap.cs b/Orm/Xtensive.Orm/Orm/Upgrade/Internals/PartialIndexInfoMap.cs
index d49208859..1c24fdd73 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/Internals/PartialIndexInfoMap.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/Internals/PartialIndexInfoMap.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2013.07.18
 
-using System;
-using System.Collections.Generic;
 using Xtensive.Core;
 using Xtensive.Orm.Model.Stored;
 using Xtensive.Orm.Providers;
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/Internals/RuleMatcher.cs b/Orm/Xtensive.Orm/Orm/Upgrade/Internals/RuleMatcher.cs
index 3b8a647e1..f15201038 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/Internals/RuleMatcher.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/Internals/RuleMatcher.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2013.08.20
 
-using System.Collections.Generic;
-using System.Linq;
 using System.Text.RegularExpressions;
 using Xtensive.Sql.Model;
 
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/Internals/SchemaComparer.cs b/Orm/Xtensive.Orm/Orm/Upgrade/Internals/SchemaComparer.cs
index d992ef9fb..bccf7856a 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/Internals/SchemaComparer.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/Internals/SchemaComparer.cs
@@ -4,9 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.05.01
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Collections;
 using Xtensive.Core;
 using Xtensive.Modelling.Actions;
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/Internals/SchemaExtractor.cs b/Orm/Xtensive.Orm/Orm/Upgrade/Internals/SchemaExtractor.cs
index ed3185b35..8017b75a2 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/Internals/SchemaExtractor.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/Internals/SchemaExtractor.cs
@@ -4,10 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.03.16
 
-using System.Collections.Generic;
-using System.Linq;
-using System.Threading;
-using System.Threading.Tasks;
 using Xtensive.Core;
 using Xtensive.Orm.Model.Stored;
 using Xtensive.Orm.Providers;
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/Internals/SchemaUpgrader.cs b/Orm/Xtensive.Orm/Orm/Upgrade/Internals/SchemaUpgrader.cs
index 62a74ba4d..af11a5ac8 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/Internals/SchemaUpgrader.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/Internals/SchemaUpgrader.cs
@@ -4,11 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.04.06
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Threading;
-using System.Threading.Tasks;
 using Xtensive.Core;
 using Xtensive.Orm.Logging;
 using Xtensive.Modelling.Actions;
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/Internals/SqlActionTranslator.cs b/Orm/Xtensive.Orm/Orm/Upgrade/Internals/SqlActionTranslator.cs
index 0ab2ee693..62e684c04 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/Internals/SqlActionTranslator.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/Internals/SqlActionTranslator.cs
@@ -4,10 +4,7 @@
 // Created by: Ivan Galkin
 // Created:    2009.04.24
 
-using System;
-using System.Collections.Generic;
 using System.Globalization;
-using System.Linq;
 using Xtensive.Core;
 using Xtensive.Orm.Providers;
 using Xtensive.Reflection;
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/Internals/SqlAsyncWorker.cs b/Orm/Xtensive.Orm/Orm/Upgrade/Internals/SqlAsyncWorker.cs
index e8e22933b..5542ef103 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/Internals/SqlAsyncWorker.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/Internals/SqlAsyncWorker.cs
@@ -2,11 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Threading;
-using System.Threading.Tasks;
 using Xtensive.Core;
 using Xtensive.Orm.Providers;
 using Xtensive.Sql;
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/Internals/SqlModelConverter.cs b/Orm/Xtensive.Orm/Orm/Upgrade/Internals/SqlModelConverter.cs
index d1858fdfa..7acd843bd 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/Internals/SqlModelConverter.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/Internals/SqlModelConverter.cs
@@ -4,9 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.03.31
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Core;
 using Xtensive.Orm.Model.Stored;
 using Xtensive.Orm.Providers;
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/Internals/SqlWorker.cs b/Orm/Xtensive.Orm/Orm/Upgrade/Internals/SqlWorker.cs
index a9b063fd0..83f2a4eec 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/Internals/SqlWorker.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/Internals/SqlWorker.cs
@@ -4,9 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.03.15
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Core;
 using Xtensive.Orm.Providers;
 using Xtensive.Sql;
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/Internals/SqlWorkerTask.cs b/Orm/Xtensive.Orm/Orm/Upgrade/Internals/SqlWorkerTask.cs
index 6212a2ec7..023c9dfbe 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/Internals/SqlWorkerTask.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/Internals/SqlWorkerTask.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.03.15
 
-using System;
 
 namespace Xtensive.Orm.Upgrade
 {
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/Internals/StageModelFilter.cs b/Orm/Xtensive.Orm/Orm/Upgrade/Internals/StageModelFilter.cs
index 56e061850..cba0b3f7a 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/Internals/StageModelFilter.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/Internals/StageModelFilter.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.03.14
 
-using System;
-using System.Collections.Generic;
 using System.Reflection;
 using Xtensive.Core;
 using Xtensive.Orm.Building.Builders;
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/Internals/TypeIdProvider.cs b/Orm/Xtensive.Orm/Orm/Upgrade/Internals/TypeIdProvider.cs
index 773b2fba5..d33381066 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/Internals/TypeIdProvider.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/Internals/TypeIdProvider.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.03.19
 
-using System;
-using System.Collections.Generic;
 using Xtensive.Core;
 using Xtensive.Orm.Building.Builders;
 using Xtensive.Orm.Model;
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/Internals/UpgradeActionSequenceBuilder.cs b/Orm/Xtensive.Orm/Orm/Upgrade/Internals/UpgradeActionSequenceBuilder.cs
index 06137103d..70e37f5dc 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/Internals/UpgradeActionSequenceBuilder.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/Internals/UpgradeActionSequenceBuilder.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.05.18
 
-using System;
-using System.Collections.Generic;
 using Xtensive.Core;
 using Xtensive.Orm.Providers;
 using Xtensive.Sql;
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/Internals/UpgradeHintValidator.cs b/Orm/Xtensive.Orm/Orm/Upgrade/Internals/UpgradeHintValidator.cs
index fbab6d261..ef693f66d 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/Internals/UpgradeHintValidator.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/Internals/UpgradeHintValidator.cs
@@ -4,9 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2015.01.21
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Collections;
 using Xtensive.Core;
 using Xtensive.Orm.Model.Stored;
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/Internals/UpgradeHintsProcessingResult.cs b/Orm/Xtensive.Orm/Orm/Upgrade/Internals/UpgradeHintsProcessingResult.cs
index 4727ba40a..24e65d7de 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/Internals/UpgradeHintsProcessingResult.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/Internals/UpgradeHintsProcessingResult.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2015.01.22
 
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Collections;
 using Xtensive.Core;
 using Xtensive.Orm.Model.Stored;
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/Internals/UpgradeHintsProcessor.cs b/Orm/Xtensive.Orm/Orm/Upgrade/Internals/UpgradeHintsProcessor.cs
index e90f7eaf4..56f1339dd 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/Internals/UpgradeHintsProcessor.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/Internals/UpgradeHintsProcessor.cs
@@ -4,9 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2015.01.21
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Collections;
 using Xtensive.Core;
 using Xtensive.Orm.Model;
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/Internals/UpgradeServiceAccessor.cs b/Orm/Xtensive.Orm/Orm/Upgrade/Internals/UpgradeServiceAccessor.cs
index 5eb3ae100..0aac0f6af 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/Internals/UpgradeServiceAccessor.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/Internals/UpgradeServiceAccessor.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.03.14
 
-using System;
-using System.Collections.Generic;
 using System.Collections.ObjectModel;
 using System.Reflection;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/Internals/WellKnownUpgradeTypes.cs b/Orm/Xtensive.Orm/Orm/Upgrade/Internals/WellKnownUpgradeTypes.cs
index da7e2e84a..d4a735bb9 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/Internals/WellKnownUpgradeTypes.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/Internals/WellKnownUpgradeTypes.cs
@@ -2,7 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
 using Xtensive.Orm.Upgrade.Model;
 
 namespace Xtensive.Orm.Upgrade
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/Model/ColumnInfoCollection.cs b/Orm/Xtensive.Orm/Orm/Upgrade/Model/ColumnInfoCollection.cs
index a90e58440..6d0a26503 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/Model/ColumnInfoCollection.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/Model/ColumnInfoCollection.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.03.20
 
-using System;
 
 using Xtensive.Modelling;
 
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/Model/ColumnInfoRef.cs b/Orm/Xtensive.Orm/Orm/Upgrade/Model/ColumnInfoRef.cs
index 7d92afd47..482cd11fd 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/Model/ColumnInfoRef.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/Model/ColumnInfoRef.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.03.20
 
-using System;
 
 
 namespace Xtensive.Orm.Upgrade.Model
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/Model/Exceptions/IntegrityException.cs b/Orm/Xtensive.Orm/Orm/Upgrade/Model/Exceptions/IntegrityException.cs
index cd6e13b65..99dca8a31 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/Model/Exceptions/IntegrityException.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/Model/Exceptions/IntegrityException.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.03.23
 
-using System;
 using System.Runtime.Serialization;
 
 using Xtensive.Modelling;
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/Model/Exceptions/ValidationException.cs b/Orm/Xtensive.Orm/Orm/Upgrade/Model/Exceptions/ValidationException.cs
index 5d6acd52c..ea68a636e 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/Model/Exceptions/ValidationException.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/Model/Exceptions/ValidationException.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.03.23
 
-using System;
 using System.Runtime.Serialization;
 using System.Security;
 using System.Security.Permissions;
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/Model/ForeignKeyCollection.cs b/Orm/Xtensive.Orm/Orm/Upgrade/Model/ForeignKeyCollection.cs
index 20796c6d5..7b814092a 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/Model/ForeignKeyCollection.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/Model/ForeignKeyCollection.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.03.23
 
-using System;
 
 using Xtensive.Modelling;
 using Xtensive.Orm.Upgrade.Model;
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/Model/ForeignKeyColumnCollection.cs b/Orm/Xtensive.Orm/Orm/Upgrade/Model/ForeignKeyColumnCollection.cs
index d94d254bc..a302712f4 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/Model/ForeignKeyColumnCollection.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/Model/ForeignKeyColumnCollection.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.04.20
 
-using System;
 using Xtensive.Modelling;
 
 namespace Xtensive.Orm.Upgrade.Model
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/Model/ForeignKeyColumnRef.cs b/Orm/Xtensive.Orm/Orm/Upgrade/Model/ForeignKeyColumnRef.cs
index 001d991ae..c8903a263 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/Model/ForeignKeyColumnRef.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/Model/ForeignKeyColumnRef.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.04.20
 
-using System;
 
 using Xtensive.Modelling;
 
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/Model/ForeignKeyInfo.cs b/Orm/Xtensive.Orm/Orm/Upgrade/Model/ForeignKeyInfo.cs
index 5f87f5bb2..e3edfac90 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/Model/ForeignKeyInfo.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/Model/ForeignKeyInfo.cs
@@ -4,8 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.03.23
 
-using System;
-using System.Linq;
 using Xtensive.Core;
 using Xtensive.Reflection;
 using Xtensive.Modelling;
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/Model/FullTextColumnRef.cs b/Orm/Xtensive.Orm/Orm/Upgrade/Model/FullTextColumnRef.cs
index 1de0251bb..089d4d098 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/Model/FullTextColumnRef.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/Model/FullTextColumnRef.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2010.01.14
 
-using System;
 using Xtensive.Modelling;
 using Xtensive.Modelling.Attributes;
 
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/Model/FullTextColumnRefCollection.cs b/Orm/Xtensive.Orm/Orm/Upgrade/Model/FullTextColumnRefCollection.cs
index e080c8a67..00ba6d482 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/Model/FullTextColumnRefCollection.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/Model/FullTextColumnRefCollection.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2010.01.14
 
-using System;
 using System.Diagnostics;
 
 using Xtensive.Modelling;
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/Model/FullTextIndexInfoCollection.cs b/Orm/Xtensive.Orm/Orm/Upgrade/Model/FullTextIndexInfoCollection.cs
index cba4efdfa..fb96e7aae 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/Model/FullTextIndexInfoCollection.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/Model/FullTextIndexInfoCollection.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2010.01.25
 
-using System;
 
 using Xtensive.Modelling;
 
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/Model/IncludedColumnRef.cs b/Orm/Xtensive.Orm/Orm/Upgrade/Model/IncludedColumnRef.cs
index 18519d6f5..8b57973be 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/Model/IncludedColumnRef.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/Model/IncludedColumnRef.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.03.24
 
-using System;
 
 using Xtensive.Modelling;
 
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/Model/IncludedColumnRefCollection.cs b/Orm/Xtensive.Orm/Orm/Upgrade/Model/IncludedColumnRefCollection.cs
index b86e94155..d548904de 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/Model/IncludedColumnRefCollection.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/Model/IncludedColumnRefCollection.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.03.24
 
-using System;
 
 using Xtensive.Modelling;
 
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/Model/KeyColumnRef.cs b/Orm/Xtensive.Orm/Orm/Upgrade/Model/KeyColumnRef.cs
index 446bfe634..b9a35272a 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/Model/KeyColumnRef.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/Model/KeyColumnRef.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.03.20
 
-using System;
 using Xtensive.Core;
 
 using Xtensive.Modelling;
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/Model/KeyColumnRefCollection.cs b/Orm/Xtensive.Orm/Orm/Upgrade/Model/KeyColumnRefCollection.cs
index 30473adec..55b627990 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/Model/KeyColumnRefCollection.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/Model/KeyColumnRefCollection.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.03.20
 
-using System;
 
 
 namespace Xtensive.Orm.Upgrade.Model
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/Model/KeyColumnRef{TParent}.cs b/Orm/Xtensive.Orm/Orm/Upgrade/Model/KeyColumnRef{TParent}.cs
index 33afbc2e0..a891afa41 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/Model/KeyColumnRef{TParent}.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/Model/KeyColumnRef{TParent}.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.03.20
 
-using System;
 using Xtensive.Core;
 using Xtensive.Modelling.Attributes;
 
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/Model/NodeBase.cs b/Orm/Xtensive.Orm/Orm/Upgrade/Model/NodeBase.cs
index e4beaa825..51147a17a 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/Model/NodeBase.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/Model/NodeBase.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.03.20
 
-using System;
 
 using Xtensive.Modelling;
 
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/Model/NodeCollectionBase.cs b/Orm/Xtensive.Orm/Orm/Upgrade/Model/NodeCollectionBase.cs
index eb466fd68..f90f369cd 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/Model/NodeCollectionBase.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/Model/NodeCollectionBase.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.03.20
 
-using System;
 using Xtensive.Modelling;
 
 namespace Xtensive.Orm.Upgrade.Model
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/Model/PartialIndexFilterInfo.cs b/Orm/Xtensive.Orm/Orm/Upgrade/Model/PartialIndexFilterInfo.cs
index 13e68ff93..f042703c7 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/Model/PartialIndexFilterInfo.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/Model/PartialIndexFilterInfo.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2011.10.13
 
-using System;
 using Xtensive.Core;
 
 namespace Xtensive.Orm.Upgrade.Model
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/Model/PrimaryIndexInfo.cs b/Orm/Xtensive.Orm/Orm/Upgrade/Model/PrimaryIndexInfo.cs
index b9b01a627..f6e0606fc 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/Model/PrimaryIndexInfo.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/Model/PrimaryIndexInfo.cs
@@ -4,8 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.03.20
 
-using System;
-using System.Linq;
 using Xtensive.Core;
 using Xtensive.Modelling;
 using Xtensive.Modelling.Attributes;
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/Model/PrimaryKeyColumnRef.cs b/Orm/Xtensive.Orm/Orm/Upgrade/Model/PrimaryKeyColumnRef.cs
index 3ac334747..9f7f49276 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/Model/PrimaryKeyColumnRef.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/Model/PrimaryKeyColumnRef.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.03.20
 
-using System;
 using Xtensive.Core;
 
 using Xtensive.Modelling;
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/Model/PrimaryKeyColumnRefCollection.cs b/Orm/Xtensive.Orm/Orm/Upgrade/Model/PrimaryKeyColumnRefCollection.cs
index 6bf5e3783..69a4e6797 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/Model/PrimaryKeyColumnRefCollection.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/Model/PrimaryKeyColumnRefCollection.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.03.20
 
-using System;
 
 
 namespace Xtensive.Orm.Upgrade.Model
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/Model/Ref.cs b/Orm/Xtensive.Orm/Orm/Upgrade/Model/Ref.cs
index 5eb2cdf75..af84f53b4 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/Model/Ref.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/Model/Ref.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.03.20
 
-using System;
 using Xtensive.Core;
 using Xtensive.Modelling;
 using Xtensive.Modelling.Attributes;
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/Model/ReferentialAction.cs b/Orm/Xtensive.Orm/Orm/Upgrade/Model/ReferentialAction.cs
index 8b49c7b82..1f855eea4 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/Model/ReferentialAction.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/Model/ReferentialAction.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.03.17
 
-using System;
 
 namespace Xtensive.Orm.Upgrade.Model
 {
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/Model/SecondaryIndexInfo.cs b/Orm/Xtensive.Orm/Orm/Upgrade/Model/SecondaryIndexInfo.cs
index 81887eef1..573867a14 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/Model/SecondaryIndexInfo.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/Model/SecondaryIndexInfo.cs
@@ -4,8 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.03.20
 
-using System;
-using System.Linq;
 using Xtensive.Core;
 using Xtensive.Modelling;
 using Xtensive.Modelling.Attributes;
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/Model/SecondaryIndexInfoCollection.cs b/Orm/Xtensive.Orm/Orm/Upgrade/Model/SecondaryIndexInfoCollection.cs
index 853661a48..46209c6ba 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/Model/SecondaryIndexInfoCollection.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/Model/SecondaryIndexInfoCollection.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.03.20
 
-using System;
 
 using Xtensive.Modelling;
 
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/Model/SequenceInfoCollection.cs b/Orm/Xtensive.Orm/Orm/Upgrade/Model/SequenceInfoCollection.cs
index 33145e64f..34b0ddaaa 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/Model/SequenceInfoCollection.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/Model/SequenceInfoCollection.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.04.29
 
-using System;
 
 using Xtensive.Modelling;
 
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/Model/StorageColumnInfo.cs b/Orm/Xtensive.Orm/Orm/Upgrade/Model/StorageColumnInfo.cs
index f87a2bae9..3fb5ed59b 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/Model/StorageColumnInfo.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/Model/StorageColumnInfo.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.03.20
 
-using System;
 using Xtensive.Core;
 using Xtensive.Modelling;
 using Xtensive.Modelling.Attributes;
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/Model/StorageFullTextIndexInfo.cs b/Orm/Xtensive.Orm/Orm/Upgrade/Model/StorageFullTextIndexInfo.cs
index c2b19636f..0f905e734 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/Model/StorageFullTextIndexInfo.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/Model/StorageFullTextIndexInfo.cs
@@ -4,8 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2010.01.14
 
-using System;
-using System.Linq;
 using Xtensive.Core;
 
 using Xtensive.Modelling;
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/Model/StorageIndexInfo.cs b/Orm/Xtensive.Orm/Orm/Upgrade/Model/StorageIndexInfo.cs
index 75bedeaff..acee34ec0 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/Model/StorageIndexInfo.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/Model/StorageIndexInfo.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.03.24
 
-using System;
 using Xtensive.Core;
 
 using Xtensive.Modelling.Attributes;
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/Model/StorageModel.cs b/Orm/Xtensive.Orm/Orm/Upgrade/Model/StorageModel.cs
index 88cf14909..a9d148f6d 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/Model/StorageModel.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/Model/StorageModel.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.03.20
 
-using System;
 
 using Xtensive.Modelling;
 using Xtensive.Modelling.Actions;
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/Model/StorageSequenceInfo.cs b/Orm/Xtensive.Orm/Orm/Upgrade/Model/StorageSequenceInfo.cs
index c7a5d059f..007658823 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/Model/StorageSequenceInfo.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/Model/StorageSequenceInfo.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.04.29
 
-using System;
 using Xtensive.Core;
 using Xtensive.Modelling;
 using Xtensive.Modelling.Attributes;
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/Model/StorageTypeInfo.cs b/Orm/Xtensive.Orm/Orm/Upgrade/Model/StorageTypeInfo.cs
index ea3c319e1..faa5b1821 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/Model/StorageTypeInfo.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/Model/StorageTypeInfo.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.03.24
 
-using System;
 using System.Globalization;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/Model/TableInfo.cs b/Orm/Xtensive.Orm/Orm/Upgrade/Model/TableInfo.cs
index 07beb0e68..387751040 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/Model/TableInfo.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/Model/TableInfo.cs
@@ -4,10 +4,8 @@
 // Created by: Ivan Galkin
 // Created:    2009.03.24
 
-using System;
 using Xtensive.Modelling;
 using Xtensive.Modelling.Attributes;
-using System.Collections.Generic;
 
 namespace Xtensive.Orm.Upgrade.Model
 {
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/Model/TableInfoCollection.cs b/Orm/Xtensive.Orm/Orm/Upgrade/Model/TableInfoCollection.cs
index dde50c7d9..5d322e23a 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/Model/TableInfoCollection.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/Model/TableInfoCollection.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.03.24
 
-using System;
 
 using Xtensive.Modelling;
 
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/Model/ValueColumnRef.cs b/Orm/Xtensive.Orm/Orm/Upgrade/Model/ValueColumnRef.cs
index 639ece5bd..4f0707c6d 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/Model/ValueColumnRef.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/Model/ValueColumnRef.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.03.24
 
-using System;
 
 using Xtensive.Modelling;
 
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/Model/ValueColumnRefCollection.cs b/Orm/Xtensive.Orm/Orm/Upgrade/Model/ValueColumnRefCollection.cs
index 12199ac4b..7b9375122 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/Model/ValueColumnRefCollection.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/Model/ValueColumnRefCollection.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.03.24
 
-using System;
 
 using Xtensive.Modelling;
 
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/SchemaComparisonResult.cs b/Orm/Xtensive.Orm/Orm/Upgrade/SchemaComparisonResult.cs
index 819e94ea0..f01ef46de 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/SchemaComparisonResult.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/SchemaComparisonResult.cs
@@ -4,10 +4,7 @@
 // Created by: Ivan Galkin
 // Created:    2009.05.01
 
-using System;
-using System.Collections.Generic;
 using System.Collections.ObjectModel;
-using System.Linq;
 using Xtensive.Core;
 using Xtensive.Modelling.Actions;
 using Xtensive.Modelling.Comparison;
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/SchemaExtractionResult.cs b/Orm/Xtensive.Orm/Orm/Upgrade/SchemaExtractionResult.cs
index 93f7e6c49..6a0e9c5f3 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/SchemaExtractionResult.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/SchemaExtractionResult.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kulakov
 // Created:    2013.09.02
 
-using System.Collections.Generic;
 using Xtensive.Sql;
 using Xtensive.Sql.Model;
 
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/SystemUpgradeHandler.cs b/Orm/Xtensive.Orm/Orm/Upgrade/SystemUpgradeHandler.cs
index fa3a0498e..21f9d6056 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/SystemUpgradeHandler.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/SystemUpgradeHandler.cs
@@ -4,12 +4,7 @@
 // Created by: Alex Yakunin
 // Created:    2009.05.01
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Reflection;
-using System.Threading;
-using System.Threading.Tasks;
 using Xtensive.Core;
 using Xtensive.Orm.Building.Builders;
 using Xtensive.Orm.Configuration;
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/TypeConversionVerifier.cs b/Orm/Xtensive.Orm/Orm/Upgrade/TypeConversionVerifier.cs
index 9341982e2..919c0333b 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/TypeConversionVerifier.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/TypeConversionVerifier.cs
@@ -4,8 +4,6 @@
 // Created by: Alexander Nikolaev
 // Created:    2009.05.28
 
-using System;
-using System.Collections.Generic;
 using Xtensive.Core;
 using Xtensive.Reflection;
 using Xtensive.Orm.Upgrade.Model;
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/UpgradeActionSequence.cs b/Orm/Xtensive.Orm/Orm/Upgrade/UpgradeActionSequence.cs
index f9a596748..42ee99edf 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/UpgradeActionSequence.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/UpgradeActionSequence.cs
@@ -4,12 +4,7 @@
 // Created by: Dmitri Maximov
 // Created:    2011.07.15
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
-using System.Linq;
-using System.Threading;
-using System.Threading.Tasks;
 using Xtensive.Core;
 
 namespace Xtensive.Orm.Upgrade
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/UpgradeContext.cs b/Orm/Xtensive.Orm/Orm/Upgrade/UpgradeContext.cs
index fb01486de..b72f12e88 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/UpgradeContext.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/UpgradeContext.cs
@@ -4,8 +4,6 @@
 // Created by: Aleksey Gamzov
 // Created:    2008.12.30
 
-using System;
-using System.Collections.Generic;
 using System.Data.Common;
 using System.Reflection;
 using Xtensive.Collections;
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/UpgradeHandler.cs b/Orm/Xtensive.Orm/Orm/Upgrade/UpgradeHandler.cs
index 6f3c0a89b..4deff741e 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/UpgradeHandler.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/UpgradeHandler.cs
@@ -4,14 +4,9 @@
 // Created by: Alex Yakunin
 // Created:    2009.04.30
 
-using System;
-using System.Collections.Generic;
 using System.Reflection;
 using Xtensive.Core;
 using Xtensive.Reflection;
-using System.Linq;
-using System.Threading.Tasks;
-using System.Threading;
 
 namespace Xtensive.Orm.Upgrade
 {
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/UpgradeStage.cs b/Orm/Xtensive.Orm/Orm/Upgrade/UpgradeStage.cs
index 9ffc0383c..83e64a7fb 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/UpgradeStage.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/UpgradeStage.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2009.04.30
 
-using System;
 
 namespace Xtensive.Orm.Upgrade
 {
diff --git a/Orm/Xtensive.Orm/Orm/Upgrade/UpgradingDomainBuilder.cs b/Orm/Xtensive.Orm/Orm/Upgrade/UpgradingDomainBuilder.cs
index 3abe3670f..6dd29f4d1 100644
--- a/Orm/Xtensive.Orm/Orm/Upgrade/UpgradingDomainBuilder.cs
+++ b/Orm/Xtensive.Orm/Orm/Upgrade/UpgradingDomainBuilder.cs
@@ -4,13 +4,8 @@
 // Created by: Alex Kofman
 // Created:    2009.04.23
 
-using System;
-using System.Collections.Generic;
 using System.Collections.ObjectModel;
-using System.Linq;
 using System.Reflection;
-using System.Threading;
-using System.Threading.Tasks;
 using Xtensive.Core;
 using Xtensive.IoC;
 using Xtensive.Modelling.Comparison;
diff --git a/Orm/Xtensive.Orm/Orm/UrlInfo.cs b/Orm/Xtensive.Orm/Orm/UrlInfo.cs
index 82f49b11f..8d961ada1 100644
--- a/Orm/Xtensive.Orm/Orm/UrlInfo.cs
+++ b/Orm/Xtensive.Orm/Orm/UrlInfo.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2007.06.08
 
-using System;
-using System.Collections.Generic;
 using System.Collections.ObjectModel;
 using System.ComponentModel;
 using System.Diagnostics;
diff --git a/Orm/Xtensive.Orm/Orm/Validation/Constraints/EmailConstraint.cs b/Orm/Xtensive.Orm/Orm/Validation/Constraints/EmailConstraint.cs
index 75905eb4a..b4cbad22b 100644
--- a/Orm/Xtensive.Orm/Orm/Validation/Constraints/EmailConstraint.cs
+++ b/Orm/Xtensive.Orm/Orm/Validation/Constraints/EmailConstraint.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Kofman
 // Created:    2009.05.27
 
-using System;
 using System.Text.RegularExpressions;
 using Xtensive.Orm.Model;
 using Xtensive.Reflection;
diff --git a/Orm/Xtensive.Orm/Orm/Validation/Constraints/FutureConstraint.cs b/Orm/Xtensive.Orm/Orm/Validation/Constraints/FutureConstraint.cs
index cbabb2b0f..074d77f63 100644
--- a/Orm/Xtensive.Orm/Orm/Validation/Constraints/FutureConstraint.cs
+++ b/Orm/Xtensive.Orm/Orm/Validation/Constraints/FutureConstraint.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Kofman
 // Created:    2009.05.27
 
-using System;
 using Xtensive.Orm.Model;
 using Xtensive.Reflection;
 
diff --git a/Orm/Xtensive.Orm/Orm/Validation/Constraints/NotEmptyConstraint.cs b/Orm/Xtensive.Orm/Orm/Validation/Constraints/NotEmptyConstraint.cs
index d1fe8945d..59bd7f609 100644
--- a/Orm/Xtensive.Orm/Orm/Validation/Constraints/NotEmptyConstraint.cs
+++ b/Orm/Xtensive.Orm/Orm/Validation/Constraints/NotEmptyConstraint.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Kofman
 // Created:    2009.05.27
 
-using System;
 using Xtensive.Orm.Model;
 using Xtensive.Reflection;
 
diff --git a/Orm/Xtensive.Orm/Orm/Validation/Constraints/NotNullConstraint.cs b/Orm/Xtensive.Orm/Orm/Validation/Constraints/NotNullConstraint.cs
index edd2be36f..253d81d4c 100644
--- a/Orm/Xtensive.Orm/Orm/Validation/Constraints/NotNullConstraint.cs
+++ b/Orm/Xtensive.Orm/Orm/Validation/Constraints/NotNullConstraint.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Kofman
 // Created:    2009.05.27
 
-using System;
 
 namespace Xtensive.Orm.Validation
 {
diff --git a/Orm/Xtensive.Orm/Orm/Validation/Constraints/NotNullOrEmptyConstraint.cs b/Orm/Xtensive.Orm/Orm/Validation/Constraints/NotNullOrEmptyConstraint.cs
index 40f28c7ae..cd29c8638 100644
--- a/Orm/Xtensive.Orm/Orm/Validation/Constraints/NotNullOrEmptyConstraint.cs
+++ b/Orm/Xtensive.Orm/Orm/Validation/Constraints/NotNullOrEmptyConstraint.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Kofman
 // Created:    2009.05.27
 
-using System;
 using Xtensive.Orm.Model;
 using Xtensive.Reflection;
 
diff --git a/Orm/Xtensive.Orm/Orm/Validation/Constraints/PastConstraint.cs b/Orm/Xtensive.Orm/Orm/Validation/Constraints/PastConstraint.cs
index 48b04691f..2dfc7609b 100644
--- a/Orm/Xtensive.Orm/Orm/Validation/Constraints/PastConstraint.cs
+++ b/Orm/Xtensive.Orm/Orm/Validation/Constraints/PastConstraint.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Kofman
 // Created:    2009.05.27
 
-using System;
 using Xtensive.Reflection;
 
 namespace Xtensive.Orm.Validation
diff --git a/Orm/Xtensive.Orm/Orm/Validation/Constraints/RangeConstraint.cs b/Orm/Xtensive.Orm/Orm/Validation/Constraints/RangeConstraint.cs
index 51d643d4c..b7e1ce277 100644
--- a/Orm/Xtensive.Orm/Orm/Validation/Constraints/RangeConstraint.cs
+++ b/Orm/Xtensive.Orm/Orm/Validation/Constraints/RangeConstraint.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Kofman
 // Created:    2008.07.25
 
-using System;
-using System.Collections.Generic;
 using Xtensive.Comparison;
 using Xtensive.Orm.Model;
 using Xtensive.Reflection;
diff --git a/Orm/Xtensive.Orm/Orm/Validation/Constraints/RegexConstraint.cs b/Orm/Xtensive.Orm/Orm/Validation/Constraints/RegexConstraint.cs
index 0ce05f7a5..3382a8405 100644
--- a/Orm/Xtensive.Orm/Orm/Validation/Constraints/RegexConstraint.cs
+++ b/Orm/Xtensive.Orm/Orm/Validation/Constraints/RegexConstraint.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Kofman
 // Created:    2008.07.23
 
-using System;
 using System.Text.RegularExpressions;
 using Xtensive.Reflection;
 
diff --git a/Orm/Xtensive.Orm/Orm/Validation/EntityErrorInfo.cs b/Orm/Xtensive.Orm/Orm/Validation/EntityErrorInfo.cs
index ac5f87c9f..dad23f516 100644
--- a/Orm/Xtensive.Orm/Orm/Validation/EntityErrorInfo.cs
+++ b/Orm/Xtensive.Orm/Orm/Validation/EntityErrorInfo.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2013.09.09
 
-using System.Collections.Generic;
 using Xtensive.Core;
 
 namespace Xtensive.Orm.Validation
diff --git a/Orm/Xtensive.Orm/Orm/Validation/EntitySetFieldValidator.cs b/Orm/Xtensive.Orm/Orm/Validation/EntitySetFieldValidator.cs
index f6885e0ae..fb220c008 100644
--- a/Orm/Xtensive.Orm/Orm/Validation/EntitySetFieldValidator.cs
+++ b/Orm/Xtensive.Orm/Orm/Validation/EntitySetFieldValidator.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2013.09.11
 
-using System;
 
 namespace Xtensive.Orm.Validation
 {
diff --git a/Orm/Xtensive.Orm/Orm/Validation/EntityValidator.cs b/Orm/Xtensive.Orm/Orm/Validation/EntityValidator.cs
index d2752c374..f82e356f3 100644
--- a/Orm/Xtensive.Orm/Orm/Validation/EntityValidator.cs
+++ b/Orm/Xtensive.Orm/Orm/Validation/EntityValidator.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2013.09.11
 
-using System;
 
 namespace Xtensive.Orm.Validation
 {
diff --git a/Orm/Xtensive.Orm/Orm/Validation/Exceptions/ValidationFailedException.cs b/Orm/Xtensive.Orm/Orm/Validation/Exceptions/ValidationFailedException.cs
index 929acc3d7..12664c85c 100644
--- a/Orm/Xtensive.Orm/Orm/Validation/Exceptions/ValidationFailedException.cs
+++ b/Orm/Xtensive.Orm/Orm/Validation/Exceptions/ValidationFailedException.cs
@@ -1,5 +1,3 @@
-using System;
-using System.Collections.Generic;
 using System.Runtime.Serialization;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Orm/Validation/Internals/RealValidationContext.cs b/Orm/Xtensive.Orm/Orm/Validation/Internals/RealValidationContext.cs
index 0caef363f..761a17877 100644
--- a/Orm/Xtensive.Orm/Orm/Validation/Internals/RealValidationContext.cs
+++ b/Orm/Xtensive.Orm/Orm/Validation/Internals/RealValidationContext.cs
@@ -4,9 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2013.09.12
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Orm.Model;
 
 namespace Xtensive.Orm.Validation
diff --git a/Orm/Xtensive.Orm/Orm/Validation/Internals/ValidationContext.cs b/Orm/Xtensive.Orm/Orm/Validation/Internals/ValidationContext.cs
index 2ac95236f..293525542 100644
--- a/Orm/Xtensive.Orm/Orm/Validation/Internals/ValidationContext.cs
+++ b/Orm/Xtensive.Orm/Orm/Validation/Internals/ValidationContext.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.01.05
 
-using System.Collections.Generic;
 using Xtensive.Orm.Model;
 
 namespace Xtensive.Orm.Validation
diff --git a/Orm/Xtensive.Orm/Orm/Validation/Internals/VoidValidationContext.cs b/Orm/Xtensive.Orm/Orm/Validation/Internals/VoidValidationContext.cs
index 99a525a8e..4b338babd 100644
--- a/Orm/Xtensive.Orm/Orm/Validation/Internals/VoidValidationContext.cs
+++ b/Orm/Xtensive.Orm/Orm/Validation/Internals/VoidValidationContext.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2013.09.12
 
-using System.Collections.Generic;
 using Xtensive.Orm.Model;
 
 namespace Xtensive.Orm.Validation
diff --git a/Orm/Xtensive.Orm/Orm/Validation/ObjectValidator.cs b/Orm/Xtensive.Orm/Orm/Validation/ObjectValidator.cs
index da3d3798f..13eb06c8e 100644
--- a/Orm/Xtensive.Orm/Orm/Validation/ObjectValidator.cs
+++ b/Orm/Xtensive.Orm/Orm/Validation/ObjectValidator.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2013.09.06
 
-using System;
 using Xtensive.Core;
 using Xtensive.Orm.Model;
 
diff --git a/Orm/Xtensive.Orm/Orm/Validation/PropertyValidator.cs b/Orm/Xtensive.Orm/Orm/Validation/PropertyValidator.cs
index 05f4e3c3d..ca18f7aa7 100644
--- a/Orm/Xtensive.Orm/Orm/Validation/PropertyValidator.cs
+++ b/Orm/Xtensive.Orm/Orm/Validation/PropertyValidator.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2013.09.06
 
-using System;
 using Xtensive.Core;
 using Xtensive.Orm.Model;
 
diff --git a/Orm/Xtensive.Orm/Orm/Validation/StructureFieldValidator.cs b/Orm/Xtensive.Orm/Orm/Validation/StructureFieldValidator.cs
index 5c3880a6c..40a97c07c 100644
--- a/Orm/Xtensive.Orm/Orm/Validation/StructureFieldValidator.cs
+++ b/Orm/Xtensive.Orm/Orm/Validation/StructureFieldValidator.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2013.09.11
 
-using System;
 
 namespace Xtensive.Orm.Validation
 {
diff --git a/Orm/Xtensive.Orm/Orm/VersionCapturer.cs b/Orm/Xtensive.Orm/Orm/VersionCapturer.cs
index 1d96ac0da..70c707446 100644
--- a/Orm/Xtensive.Orm/Orm/VersionCapturer.cs
+++ b/Orm/Xtensive.Orm/Orm/VersionCapturer.cs
@@ -4,12 +4,9 @@
 // Created by: Alex Yakunin
 // Created:    2010.03.01
 
-using System;
-using System.Collections.Generic;
 using Xtensive.Core;
 
 using Xtensive.Tuples.Transform;
-using System.Linq;
 
 namespace Xtensive.Orm
 {
diff --git a/Orm/Xtensive.Orm/Orm/VersionInfo.cs b/Orm/Xtensive.Orm/Orm/VersionInfo.cs
index ff38fcc6c..cfda8cce7 100644
--- a/Orm/Xtensive.Orm/Orm/VersionInfo.cs
+++ b/Orm/Xtensive.Orm/Orm/VersionInfo.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.08.13
 
-using System;
 using System.Collections;
 using System.Diagnostics;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Orm/VersionSet.cs b/Orm/Xtensive.Orm/Orm/VersionSet.cs
index 09cf4ee34..3e1a22389 100644
--- a/Orm/Xtensive.Orm/Orm/VersionSet.cs
+++ b/Orm/Xtensive.Orm/Orm/VersionSet.cs
@@ -4,10 +4,7 @@
 // Created by: Alex Yakunin
 // Created:    2010.03.01
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Core;
 using Xtensive.Orm.Logging;
 
diff --git a/Orm/Xtensive.Orm/Orm/VersionValidator.cs b/Orm/Xtensive.Orm/Orm/VersionValidator.cs
index 93955fc90..0bbf06142 100644
--- a/Orm/Xtensive.Orm/Orm/VersionValidator.cs
+++ b/Orm/Xtensive.Orm/Orm/VersionValidator.cs
@@ -4,9 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.11.10
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Core;
 using Xtensive.Orm.Logging;
 
diff --git a/Orm/Xtensive.Orm/Orm/Weaving/EntityInterfaceAttribute.cs b/Orm/Xtensive.Orm/Orm/Weaving/EntityInterfaceAttribute.cs
index 9a4d317a0..890d00e2e 100644
--- a/Orm/Xtensive.Orm/Orm/Weaving/EntityInterfaceAttribute.cs
+++ b/Orm/Xtensive.Orm/Orm/Weaving/EntityInterfaceAttribute.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2013.08.26
 
-using System;
 using JetBrains.Annotations;
 
 namespace Xtensive.Orm.Weaving
diff --git a/Orm/Xtensive.Orm/Orm/Weaving/EntitySetTypeAttribute.cs b/Orm/Xtensive.Orm/Orm/Weaving/EntitySetTypeAttribute.cs
index 5b51376aa..1d35cf5eb 100644
--- a/Orm/Xtensive.Orm/Orm/Weaving/EntitySetTypeAttribute.cs
+++ b/Orm/Xtensive.Orm/Orm/Weaving/EntitySetTypeAttribute.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2013.08.22
 
-using System;
 using JetBrains.Annotations;
 
 namespace Xtensive.Orm.Weaving
diff --git a/Orm/Xtensive.Orm/Orm/Weaving/EntityTypeAttribute.cs b/Orm/Xtensive.Orm/Orm/Weaving/EntityTypeAttribute.cs
index 6e61dee0b..a5200a724 100644
--- a/Orm/Xtensive.Orm/Orm/Weaving/EntityTypeAttribute.cs
+++ b/Orm/Xtensive.Orm/Orm/Weaving/EntityTypeAttribute.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2013.08.21
 
-using System;
 using JetBrains.Annotations;
 
 namespace Xtensive.Orm.Weaving
diff --git a/Orm/Xtensive.Orm/Orm/Weaving/OverrideFieldNameAttribute.cs b/Orm/Xtensive.Orm/Orm/Weaving/OverrideFieldNameAttribute.cs
index a7234faae..539aa906f 100644
--- a/Orm/Xtensive.Orm/Orm/Weaving/OverrideFieldNameAttribute.cs
+++ b/Orm/Xtensive.Orm/Orm/Weaving/OverrideFieldNameAttribute.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2010.07.13
 
-using System;
 
 namespace Xtensive.Orm.Weaving
 {
diff --git a/Orm/Xtensive.Orm/Orm/Weaving/PersistenceImplementation.cs b/Orm/Xtensive.Orm/Orm/Weaving/PersistenceImplementation.cs
index 0d1b2462a..d51688369 100644
--- a/Orm/Xtensive.Orm/Orm/Weaving/PersistenceImplementation.cs
+++ b/Orm/Xtensive.Orm/Orm/Weaving/PersistenceImplementation.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2013.08.27
 
-using System;
 
 namespace Xtensive.Orm.Weaving
 {
diff --git a/Orm/Xtensive.Orm/Orm/Weaving/ProcessedByWeaverAttribute.cs b/Orm/Xtensive.Orm/Orm/Weaving/ProcessedByWeaverAttribute.cs
index 8d9ff89f5..afe56f1a2 100644
--- a/Orm/Xtensive.Orm/Orm/Weaving/ProcessedByWeaverAttribute.cs
+++ b/Orm/Xtensive.Orm/Orm/Weaving/ProcessedByWeaverAttribute.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2013.08.21
 
-using System;
 using JetBrains.Annotations;
 
 namespace Xtensive.Orm.Weaving
diff --git a/Orm/Xtensive.Orm/Orm/Weaving/StructureTypeAttribute.cs b/Orm/Xtensive.Orm/Orm/Weaving/StructureTypeAttribute.cs
index 1ed187cd4..47f3edaa1 100644
--- a/Orm/Xtensive.Orm/Orm/Weaving/StructureTypeAttribute.cs
+++ b/Orm/Xtensive.Orm/Orm/Weaving/StructureTypeAttribute.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2013.08.21
 
-using System;
 using JetBrains.Annotations;
 
 namespace Xtensive.Orm.Weaving
diff --git a/Orm/Xtensive.Orm/Orm/WellKnown.cs b/Orm/Xtensive.Orm/Orm/WellKnown.cs
index f4c58a57c..d5d678a54 100644
--- a/Orm/Xtensive.Orm/Orm/WellKnown.cs
+++ b/Orm/Xtensive.Orm/Orm/WellKnown.cs
@@ -4,9 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.04.21
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Collections;
 using Xtensive.Orm.Internals;
 using Xtensive.Orm.Metadata;
diff --git a/Orm/Xtensive.Orm/Reflection/AttributeHelper.cs b/Orm/Xtensive.Orm/Reflection/AttributeHelper.cs
index f7b29466f..7fa059b91 100644
--- a/Orm/Xtensive.Orm/Reflection/AttributeHelper.cs
+++ b/Orm/Xtensive.Orm/Reflection/AttributeHelper.cs
@@ -4,10 +4,7 @@
 // Created by: Alex Yakunin
 // Created:    2008.06.13
 
-using System;
-using System.Collections.Generic;
 using System.Collections.Concurrent;
-using System.Linq;
 using System.Reflection;
 using Xtensive.Core;
 using PerAttributeKey = System.ValueTuple<System.Reflection.MemberInfo, Xtensive.Reflection.AttributeSearchOptions>;
diff --git a/Orm/Xtensive.Orm/Reflection/AttributeSearchOptions.cs b/Orm/Xtensive.Orm/Reflection/AttributeSearchOptions.cs
index 21fadea92..3f868440c 100644
--- a/Orm/Xtensive.Orm/Reflection/AttributeSearchOptions.cs
+++ b/Orm/Xtensive.Orm/Reflection/AttributeSearchOptions.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.08.06
 
-using System;
 
 namespace Xtensive.Reflection
 {
diff --git a/Orm/Xtensive.Orm/Reflection/DelegateHelper.cs b/Orm/Xtensive.Orm/Reflection/DelegateHelper.cs
index 88fe84a71..3d3c7ba47 100644
--- a/Orm/Xtensive.Orm/Reflection/DelegateHelper.cs
+++ b/Orm/Xtensive.Orm/Reflection/DelegateHelper.cs
@@ -4,10 +4,7 @@
 // Created by:
 // Created:    2007.10.25
 
-using System;
 using System.Collections.Concurrent;
-using System.Collections.Generic;
-using System.Linq;
 using System.Reflection;
 using System.Reflection.Emit;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Reflection/InterfaceMapping.cs b/Orm/Xtensive.Orm/Reflection/InterfaceMapping.cs
index cf161f496..3bb3d3b94 100644
--- a/Orm/Xtensive.Orm/Reflection/InterfaceMapping.cs
+++ b/Orm/Xtensive.Orm/Reflection/InterfaceMapping.cs
@@ -4,12 +4,9 @@
 // Created by: Alex Yakunin
 // Created:    2010.08.30
 
-using System;
 using System.Reflection;
 
 using ReflectionInterfaceMapping=System.Reflection.InterfaceMapping;
-using System.Linq;
-using System.Collections.Generic;
 
 namespace Xtensive.Reflection
 {
diff --git a/Orm/Xtensive.Orm/Reflection/MemberHelper.cs b/Orm/Xtensive.Orm/Reflection/MemberHelper.cs
index 712409f5d..823f2ebbd 100644
--- a/Orm/Xtensive.Orm/Reflection/MemberHelper.cs
+++ b/Orm/Xtensive.Orm/Reflection/MemberHelper.cs
@@ -4,12 +4,10 @@
 // Created by: Alex Yakunin
 // Created:    2008.06.13
 
-using System;
 using System.Reflection;
 using System.Security;
 using System.Text;
 using Xtensive.Reflection;
-using System.Linq;
 using Xtensive.Collections;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Reflection/MethodHelper.cs b/Orm/Xtensive.Orm/Reflection/MethodHelper.cs
index aa9f859ea..025b63dee 100644
--- a/Orm/Xtensive.Orm/Reflection/MethodHelper.cs
+++ b/Orm/Xtensive.Orm/Reflection/MethodHelper.cs
@@ -4,9 +4,7 @@
 // Created by: Alex Yakunin
 // Created:    2008.01.27
 
-using System;
 using System.Diagnostics;
-using System.Linq;
 using System.Reflection;
 using JetBrains.Annotations;
 using Xtensive.Collections;
diff --git a/Orm/Xtensive.Orm/Reflection/SequenceHelper.cs b/Orm/Xtensive.Orm/Reflection/SequenceHelper.cs
index 138989800..4f21acac8 100644
--- a/Orm/Xtensive.Orm/Reflection/SequenceHelper.cs
+++ b/Orm/Xtensive.Orm/Reflection/SequenceHelper.cs
@@ -4,8 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.04.17
 
-using System;
-using System.Collections.Generic;
 
 namespace Xtensive.Reflection
 {
diff --git a/Orm/Xtensive.Orm/Reflection/TypeHelper.cs b/Orm/Xtensive.Orm/Reflection/TypeHelper.cs
index ded198e5c..f23ad0174 100644
--- a/Orm/Xtensive.Orm/Reflection/TypeHelper.cs
+++ b/Orm/Xtensive.Orm/Reflection/TypeHelper.cs
@@ -4,18 +4,14 @@
 // Created by: Nick Svetlov
 // Created:    2007.06.13
 
-using System;
 using System.Collections;
 using System.Collections.Concurrent;
-using System.Collections.Generic;
 using System.Diagnostics;
 using System.Reflection;
 using System.Reflection.Emit;
 using System.Runtime.CompilerServices;
 using System.Text;
-using System.Threading;
 using Xtensive.Collections;
-using System.Linq;
 using Xtensive.Core;
 
 using Xtensive.Sorting;
diff --git a/Orm/Xtensive.Orm/Reflection/WellKnown.Queryable.cs b/Orm/Xtensive.Orm/Reflection/WellKnown.Queryable.cs
index bce5b2cee..aae155d9a 100644
--- a/Orm/Xtensive.Orm/Reflection/WellKnown.Queryable.cs
+++ b/Orm/Xtensive.Orm/Reflection/WellKnown.Queryable.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.02.24
 
-using System.Linq;
 
 namespace Xtensive.Reflection
 {
diff --git a/Orm/Xtensive.Orm/Reflection/WellKnown.cs b/Orm/Xtensive.Orm/Reflection/WellKnown.cs
index 5934a2ff2..2aedc4199 100644
--- a/Orm/Xtensive.Orm/Reflection/WellKnown.cs
+++ b/Orm/Xtensive.Orm/Reflection/WellKnown.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.07.30
 
-using System.Linq;
 
 namespace Xtensive.Reflection
 {
diff --git a/Orm/Xtensive.Orm/Reflection/WellKnownInterfaces.cs b/Orm/Xtensive.Orm/Reflection/WellKnownInterfaces.cs
index 8f55696a3..1a41ee35a 100644
--- a/Orm/Xtensive.Orm/Reflection/WellKnownInterfaces.cs
+++ b/Orm/Xtensive.Orm/Reflection/WellKnownInterfaces.cs
@@ -2,10 +2,7 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
-using System.Linq;
 
 namespace Xtensive.Reflection
 {
diff --git a/Orm/Xtensive.Orm/Reflection/WellKnownTypes.cs b/Orm/Xtensive.Orm/Reflection/WellKnownTypes.cs
index 8a2c1244f..c8c3c53f4 100644
--- a/Orm/Xtensive.Orm/Reflection/WellKnownTypes.cs
+++ b/Orm/Xtensive.Orm/Reflection/WellKnownTypes.cs
@@ -2,9 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Linq.Expressions;
 using System.Reflection;
 using Xtensive.Orm.Linq;
diff --git a/Orm/Xtensive.Orm/Sorting/ConnectionType.cs b/Orm/Xtensive.Orm/Sorting/ConnectionType.cs
index 9eb8912c4..c701678a4 100644
--- a/Orm/Xtensive.Orm/Sorting/ConnectionType.cs
+++ b/Orm/Xtensive.Orm/Sorting/ConnectionType.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2009.12.10
 
-using System;
 
 namespace Xtensive.Sorting
 {
diff --git a/Orm/Xtensive.Orm/Sorting/Node.cs b/Orm/Xtensive.Orm/Sorting/Node.cs
index e07541db0..1a588b174 100644
--- a/Orm/Xtensive.Orm/Sorting/Node.cs
+++ b/Orm/Xtensive.Orm/Sorting/Node.cs
@@ -4,10 +4,7 @@
 // Created by: Alexey Gamzov
 // Created:    2009.03.13
 
-using System;
-using System.Collections.Generic;
 using System.Collections.ObjectModel;
-using System.Linq;
 using Xtensive.Core;
 
 
diff --git a/Orm/Xtensive.Orm/Sorting/NodeConnection.cs b/Orm/Xtensive.Orm/Sorting/NodeConnection.cs
index a877b65e8..f9fae5064 100644
--- a/Orm/Xtensive.Orm/Sorting/NodeConnection.cs
+++ b/Orm/Xtensive.Orm/Sorting/NodeConnection.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2009.03.13
 
-using System;
 using Xtensive.Core;
 
 
diff --git a/Orm/Xtensive.Orm/Sorting/TopologicalSortResult{TNodeItem, TConnectionItem}.cs b/Orm/Xtensive.Orm/Sorting/TopologicalSortResult{TNodeItem, TConnectionItem}.cs
index 845fbbe7f..f15d38fe8 100644
--- a/Orm/Xtensive.Orm/Sorting/TopologicalSortResult{TNodeItem, TConnectionItem}.cs	
+++ b/Orm/Xtensive.Orm/Sorting/TopologicalSortResult{TNodeItem, TConnectionItem}.cs	
@@ -4,8 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2009.12.10
 
-using System;
-using System.Collections.Generic;
 using System.Diagnostics;
 
 
diff --git a/Orm/Xtensive.Orm/Sorting/TopologicalSortResult{TNodeItem}.cs b/Orm/Xtensive.Orm/Sorting/TopologicalSortResult{TNodeItem}.cs
index b63a181d2..3aede6c37 100644
--- a/Orm/Xtensive.Orm/Sorting/TopologicalSortResult{TNodeItem}.cs
+++ b/Orm/Xtensive.Orm/Sorting/TopologicalSortResult{TNodeItem}.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2009.12.10
 
-using System;
-using System.Collections.Generic;
 
 
 namespace Xtensive.Sorting
diff --git a/Orm/Xtensive.Orm/Sorting/TopologicalSorter.cs b/Orm/Xtensive.Orm/Sorting/TopologicalSorter.cs
index 282ee0354..6b53225ae 100644
--- a/Orm/Xtensive.Orm/Sorting/TopologicalSorter.cs
+++ b/Orm/Xtensive.Orm/Sorting/TopologicalSorter.cs
@@ -4,10 +4,7 @@
 // Created by: Alex Yakunin
 // Created:    2008.08.07
 
-using System;
-using System.Collections.Generic;
 using Xtensive.Collections;
-using System.Linq;
 using Xtensive.Core;
 using DotNetNotNullAttribute = System.Diagnostics.CodeAnalysis.NotNullAttribute;
 using JBNotNullAttribute = JetBrains.Annotations.NotNullAttribute;
diff --git a/Orm/Xtensive.Orm/Sql/Compiler/Internals/JoinSequence.cs b/Orm/Xtensive.Orm/Sql/Compiler/Internals/JoinSequence.cs
index 0b2677b82..5646aeb92 100644
--- a/Orm/Xtensive.Orm/Sql/Compiler/Internals/JoinSequence.cs
+++ b/Orm/Xtensive.Orm/Sql/Compiler/Internals/JoinSequence.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.05.18
 
-using System.Collections.Generic;
 using System.Collections.ObjectModel;
 using Xtensive.Sql.Dml;
 
diff --git a/Orm/Xtensive.Orm/Sql/Compiler/Internals/NodeVisitor.cs b/Orm/Xtensive.Orm/Sql/Compiler/Internals/NodeVisitor.cs
index f61ee2a21..211b524d6 100644
--- a/Orm/Xtensive.Orm/Sql/Compiler/Internals/NodeVisitor.cs
+++ b/Orm/Xtensive.Orm/Sql/Compiler/Internals/NodeVisitor.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.04.23
 
-using System;
-using System.Collections.Generic;
 
 namespace Xtensive.Sql.Compiler
 {
diff --git a/Orm/Xtensive.Orm/Sql/Compiler/Internals/Nodes/ContainerNode.cs b/Orm/Xtensive.Orm/Sql/Compiler/Internals/Nodes/ContainerNode.cs
index afb1f1a8a..4f4800686 100644
--- a/Orm/Xtensive.Orm/Sql/Compiler/Internals/Nodes/ContainerNode.cs
+++ b/Orm/Xtensive.Orm/Sql/Compiler/Internals/Nodes/ContainerNode.cs
@@ -2,11 +2,8 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
 using System.Globalization;
-using System.Linq;
 using System.Text;
 using Xtensive.Sql.Model;
 
diff --git a/Orm/Xtensive.Orm/Sql/Compiler/Internals/Nodes/CycleNode.cs b/Orm/Xtensive.Orm/Sql/Compiler/Internals/Nodes/CycleNode.cs
index 2cb28479a..69e1fc37c 100644
--- a/Orm/Xtensive.Orm/Sql/Compiler/Internals/Nodes/CycleNode.cs
+++ b/Orm/Xtensive.Orm/Sql/Compiler/Internals/Nodes/CycleNode.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.11.06
 
-using System.Collections.Generic;
 
 namespace Xtensive.Sql.Compiler
 {
diff --git a/Orm/Xtensive.Orm/Sql/Compiler/Internals/Nodes/VariantNode.cs b/Orm/Xtensive.Orm/Sql/Compiler/Internals/Nodes/VariantNode.cs
index d799d1ebf..690d704e5 100644
--- a/Orm/Xtensive.Orm/Sql/Compiler/Internals/Nodes/VariantNode.cs
+++ b/Orm/Xtensive.Orm/Sql/Compiler/Internals/Nodes/VariantNode.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.04.23
 
-using System.Collections.Generic;
 
 namespace Xtensive.Sql.Compiler
 {
diff --git a/Orm/Xtensive.Orm/Sql/Compiler/Internals/PostCompiler.cs b/Orm/Xtensive.Orm/Sql/Compiler/Internals/PostCompiler.cs
index 84a4b1f6e..ac8702cde 100644
--- a/Orm/Xtensive.Orm/Sql/Compiler/Internals/PostCompiler.cs
+++ b/Orm/Xtensive.Orm/Sql/Compiler/Internals/PostCompiler.cs
@@ -4,10 +4,7 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.04.23
 
-using System;
-using System.Collections.Generic;
 using System.IO;
-using System.Linq;
 using System.Text;
 
 namespace Xtensive.Sql.Compiler
diff --git a/Orm/Xtensive.Orm/Sql/Compiler/Internals/RecursiveBinaryLogicExtractor.cs b/Orm/Xtensive.Orm/Sql/Compiler/Internals/RecursiveBinaryLogicExtractor.cs
index e71727a77..2b0c0bcfc 100644
--- a/Orm/Xtensive.Orm/Sql/Compiler/Internals/RecursiveBinaryLogicExtractor.cs
+++ b/Orm/Xtensive.Orm/Sql/Compiler/Internals/RecursiveBinaryLogicExtractor.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.08.29
 
-using System;
-using System.Collections.Generic;
 using Xtensive.Sql.Dml;
 
 namespace Xtensive.Sql.Compiler
diff --git a/Orm/Xtensive.Orm/Sql/Compiler/SqlCompilationResult.cs b/Orm/Xtensive.Orm/Sql/Compiler/SqlCompilationResult.cs
index 206d98aab..dd801f8e6 100644
--- a/Orm/Xtensive.Orm/Sql/Compiler/SqlCompilationResult.cs
+++ b/Orm/Xtensive.Orm/Sql/Compiler/SqlCompilationResult.cs
@@ -2,8 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
-using System.Collections.Generic;
 
 namespace Xtensive.Sql.Compiler
 {
diff --git a/Orm/Xtensive.Orm/Sql/Compiler/SqlCompiler.cs b/Orm/Xtensive.Orm/Sql/Compiler/SqlCompiler.cs
index 4e9f32eb6..373717e19 100644
--- a/Orm/Xtensive.Orm/Sql/Compiler/SqlCompiler.cs
+++ b/Orm/Xtensive.Orm/Sql/Compiler/SqlCompiler.cs
@@ -2,9 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Core;
 using Xtensive.Reflection;
 using Xtensive.Sql.Info;
diff --git a/Orm/Xtensive.Orm/Sql/Compiler/SqlCompilerConfiguration.cs b/Orm/Xtensive.Orm/Sql/Compiler/SqlCompilerConfiguration.cs
index 6803971e9..23d48ad20 100644
--- a/Orm/Xtensive.Orm/Sql/Compiler/SqlCompilerConfiguration.cs
+++ b/Orm/Xtensive.Orm/Sql/Compiler/SqlCompilerConfiguration.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.07.15
 
-using System;
-using System.Collections.Generic;
 using System.Collections.ObjectModel;
 using JetBrains.Annotations;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Sql/Compiler/SqlCompilerContext.cs b/Orm/Xtensive.Orm/Sql/Compiler/SqlCompilerContext.cs
index f1f455428..75caf6853 100644
--- a/Orm/Xtensive.Orm/Sql/Compiler/SqlCompilerContext.cs
+++ b/Orm/Xtensive.Orm/Sql/Compiler/SqlCompilerContext.cs
@@ -2,8 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Collections.Generic;
 
 namespace Xtensive.Sql.Compiler
 {
diff --git a/Orm/Xtensive.Orm/Sql/Compiler/SqlCompilerException.cs b/Orm/Xtensive.Orm/Sql/Compiler/SqlCompilerException.cs
index 5beadfb40..10623965c 100644
--- a/Orm/Xtensive.Orm/Sql/Compiler/SqlCompilerException.cs
+++ b/Orm/Xtensive.Orm/Sql/Compiler/SqlCompilerException.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using System.Runtime.Serialization;
 
 
diff --git a/Orm/Xtensive.Orm/Sql/Compiler/SqlCompilerNamingOptions.cs b/Orm/Xtensive.Orm/Sql/Compiler/SqlCompilerNamingOptions.cs
index f892c7591..62c123b18 100644
--- a/Orm/Xtensive.Orm/Sql/Compiler/SqlCompilerNamingOptions.cs
+++ b/Orm/Xtensive.Orm/Sql/Compiler/SqlCompilerNamingOptions.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2009.08.31
 
-using System;
 
 namespace Xtensive.Sql.Compiler
 {
diff --git a/Orm/Xtensive.Orm/Sql/Compiler/SqlCompilerNamingScope.cs b/Orm/Xtensive.Orm/Sql/Compiler/SqlCompilerNamingScope.cs
index 62f20089c..c1ec2982e 100644
--- a/Orm/Xtensive.Orm/Sql/Compiler/SqlCompilerNamingScope.cs
+++ b/Orm/Xtensive.Orm/Sql/Compiler/SqlCompilerNamingScope.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2009.08.31
 
-using System;
 
 namespace Xtensive.Sql.Compiler
 {
diff --git a/Orm/Xtensive.Orm/Sql/Compiler/SqlCompilerOutputScope.cs b/Orm/Xtensive.Orm/Sql/Compiler/SqlCompilerOutputScope.cs
index 64494fea5..e4fe3b981 100644
--- a/Orm/Xtensive.Orm/Sql/Compiler/SqlCompilerOutputScope.cs
+++ b/Orm/Xtensive.Orm/Sql/Compiler/SqlCompilerOutputScope.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 
 namespace Xtensive.Sql.Compiler
 {
diff --git a/Orm/Xtensive.Orm/Sql/Compiler/SqlParameterNameProvider.cs b/Orm/Xtensive.Orm/Sql/Compiler/SqlParameterNameProvider.cs
index f3b814e70..8fcf89d05 100644
--- a/Orm/Xtensive.Orm/Sql/Compiler/SqlParameterNameProvider.cs
+++ b/Orm/Xtensive.Orm/Sql/Compiler/SqlParameterNameProvider.cs
@@ -4,8 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2009.08.31
 
-using System;
-using System.Collections.Generic;
 
 namespace Xtensive.Sql.Compiler
 {
diff --git a/Orm/Xtensive.Orm/Sql/Compiler/SqlPostCompilerConfiguration.cs b/Orm/Xtensive.Orm/Sql/Compiler/SqlPostCompilerConfiguration.cs
index 8e4b3d181..0a2f1af62 100644
--- a/Orm/Xtensive.Orm/Sql/Compiler/SqlPostCompilerConfiguration.cs
+++ b/Orm/Xtensive.Orm/Sql/Compiler/SqlPostCompilerConfiguration.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.11.07
 
-using System.Collections.Generic;
 using System.Collections.ObjectModel;
 using JetBrains.Annotations;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Sql/Compiler/SqlTableNameProvider.cs b/Orm/Xtensive.Orm/Sql/Compiler/SqlTableNameProvider.cs
index d19efc874..664934108 100644
--- a/Orm/Xtensive.Orm/Sql/Compiler/SqlTableNameProvider.cs
+++ b/Orm/Xtensive.Orm/Sql/Compiler/SqlTableNameProvider.cs
@@ -2,7 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System.Collections.Generic;
 using Xtensive.Sql.Dml;
 
 namespace Xtensive.Sql.Compiler
diff --git a/Orm/Xtensive.Orm/Sql/Compiler/SqlTranslator.cs b/Orm/Xtensive.Orm/Sql/Compiler/SqlTranslator.cs
index 9eb356c69..c9bea0456 100644
--- a/Orm/Xtensive.Orm/Sql/Compiler/SqlTranslator.cs
+++ b/Orm/Xtensive.Orm/Sql/Compiler/SqlTranslator.cs
@@ -2,10 +2,7 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Collections.Generic;
 using System.Globalization;
-using System.Linq;
 using System.Text;
 using Xtensive.Core;
 using Xtensive.Reflection;
diff --git a/Orm/Xtensive.Orm/Sql/DbConnectionAccessorExtension.cs b/Orm/Xtensive.Orm/Sql/DbConnectionAccessorExtension.cs
index 1cc9e25a9..b09758900 100644
--- a/Orm/Xtensive.Orm/Sql/DbConnectionAccessorExtension.cs
+++ b/Orm/Xtensive.Orm/Sql/DbConnectionAccessorExtension.cs
@@ -2,7 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System.Collections.Generic;
 using Xtensive.Orm;
 
 namespace Xtensive.Sql
diff --git a/Orm/Xtensive.Orm/Sql/Ddl/Actions/SqlAction.cs b/Orm/Xtensive.Orm/Sql/Ddl/Actions/SqlAction.cs
index 4d14e8667..e3b7ee27c 100644
--- a/Orm/Xtensive.Orm/Sql/Ddl/Actions/SqlAction.cs
+++ b/Orm/Xtensive.Orm/Sql/Ddl/Actions/SqlAction.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 
 namespace Xtensive.Sql.Ddl
 {
diff --git a/Orm/Xtensive.Orm/Sql/Ddl/Actions/SqlAddColumn.cs b/Orm/Xtensive.Orm/Sql/Ddl/Actions/SqlAddColumn.cs
index 27e283db1..c014ed51b 100644
--- a/Orm/Xtensive.Orm/Sql/Ddl/Actions/SqlAddColumn.cs
+++ b/Orm/Xtensive.Orm/Sql/Ddl/Actions/SqlAddColumn.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Sql.Model;
 
 namespace Xtensive.Sql.Ddl
diff --git a/Orm/Xtensive.Orm/Sql/Ddl/Actions/SqlAddConstraint.cs b/Orm/Xtensive.Orm/Sql/Ddl/Actions/SqlAddConstraint.cs
index 2e09734d4..06fee6174 100644
--- a/Orm/Xtensive.Orm/Sql/Ddl/Actions/SqlAddConstraint.cs
+++ b/Orm/Xtensive.Orm/Sql/Ddl/Actions/SqlAddConstraint.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Sql.Model;
 
 namespace Xtensive.Sql.Ddl
diff --git a/Orm/Xtensive.Orm/Sql/Ddl/Actions/SqlAlterIdentityInfo.cs b/Orm/Xtensive.Orm/Sql/Ddl/Actions/SqlAlterIdentityInfo.cs
index b85cf7831..abcc96e6a 100644
--- a/Orm/Xtensive.Orm/Sql/Ddl/Actions/SqlAlterIdentityInfo.cs
+++ b/Orm/Xtensive.Orm/Sql/Ddl/Actions/SqlAlterIdentityInfo.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Sql.Model;
 
 namespace Xtensive.Sql.Ddl
diff --git a/Orm/Xtensive.Orm/Sql/Ddl/Actions/SqlCascadableAction.cs b/Orm/Xtensive.Orm/Sql/Ddl/Actions/SqlCascadableAction.cs
index 006b6aa88..59543dbaf 100644
--- a/Orm/Xtensive.Orm/Sql/Ddl/Actions/SqlCascadableAction.cs
+++ b/Orm/Xtensive.Orm/Sql/Ddl/Actions/SqlCascadableAction.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.08.10
 
-using System;
 
 namespace Xtensive.Sql.Ddl
 {
diff --git a/Orm/Xtensive.Orm/Sql/Ddl/Actions/SqlDropColumn.cs b/Orm/Xtensive.Orm/Sql/Ddl/Actions/SqlDropColumn.cs
index 1831f77e8..9728f874e 100644
--- a/Orm/Xtensive.Orm/Sql/Ddl/Actions/SqlDropColumn.cs
+++ b/Orm/Xtensive.Orm/Sql/Ddl/Actions/SqlDropColumn.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Sql.Model;
 
 namespace Xtensive.Sql.Ddl
diff --git a/Orm/Xtensive.Orm/Sql/Ddl/Actions/SqlDropConstraint.cs b/Orm/Xtensive.Orm/Sql/Ddl/Actions/SqlDropConstraint.cs
index 613ce4b92..7e5be762e 100644
--- a/Orm/Xtensive.Orm/Sql/Ddl/Actions/SqlDropConstraint.cs
+++ b/Orm/Xtensive.Orm/Sql/Ddl/Actions/SqlDropConstraint.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Sql.Model;
 
 namespace Xtensive.Sql.Ddl
diff --git a/Orm/Xtensive.Orm/Sql/Ddl/Actions/SqlDropDefault.cs b/Orm/Xtensive.Orm/Sql/Ddl/Actions/SqlDropDefault.cs
index 7e97f2b28..f994b0460 100644
--- a/Orm/Xtensive.Orm/Sql/Ddl/Actions/SqlDropDefault.cs
+++ b/Orm/Xtensive.Orm/Sql/Ddl/Actions/SqlDropDefault.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Sql.Model;
 
 namespace Xtensive.Sql.Ddl
diff --git a/Orm/Xtensive.Orm/Sql/Ddl/Actions/SqlRenameColumn.cs b/Orm/Xtensive.Orm/Sql/Ddl/Actions/SqlRenameColumn.cs
index 2e3a3d6d0..260933022 100644
--- a/Orm/Xtensive.Orm/Sql/Ddl/Actions/SqlRenameColumn.cs
+++ b/Orm/Xtensive.Orm/Sql/Ddl/Actions/SqlRenameColumn.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.08.10
 
-using System;
 using Xtensive.Sql.Model;
 
 namespace Xtensive.Sql.Ddl
diff --git a/Orm/Xtensive.Orm/Sql/Ddl/Actions/SqlSetDefault.cs b/Orm/Xtensive.Orm/Sql/Ddl/Actions/SqlSetDefault.cs
index 3bdefd8ea..907c7bd07 100644
--- a/Orm/Xtensive.Orm/Sql/Ddl/Actions/SqlSetDefault.cs
+++ b/Orm/Xtensive.Orm/Sql/Ddl/Actions/SqlSetDefault.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Sql.Model;
 using Xtensive.Sql.Dml;
 
diff --git a/Orm/Xtensive.Orm/Sql/Ddl/Misc/SqlAlterIdentityInfoOptions.cs b/Orm/Xtensive.Orm/Sql/Ddl/Misc/SqlAlterIdentityInfoOptions.cs
index f15147d49..6e1c2226b 100644
--- a/Orm/Xtensive.Orm/Sql/Ddl/Misc/SqlAlterIdentityInfoOptions.cs
+++ b/Orm/Xtensive.Orm/Sql/Ddl/Misc/SqlAlterIdentityInfoOptions.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 
 namespace Xtensive.Sql.Ddl
 {
diff --git a/Orm/Xtensive.Orm/Sql/Ddl/Misc/SqlAlterPartitionFunctionOption.cs b/Orm/Xtensive.Orm/Sql/Ddl/Misc/SqlAlterPartitionFunctionOption.cs
index 309a3da98..28f2dfb24 100644
--- a/Orm/Xtensive.Orm/Sql/Ddl/Misc/SqlAlterPartitionFunctionOption.cs
+++ b/Orm/Xtensive.Orm/Sql/Ddl/Misc/SqlAlterPartitionFunctionOption.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 
 namespace Xtensive.Sql.Ddl
 {
diff --git a/Orm/Xtensive.Orm/Sql/Ddl/Misc/SqlCommandType.cs b/Orm/Xtensive.Orm/Sql/Ddl/Misc/SqlCommandType.cs
index 39fc8462a..39054dab1 100644
--- a/Orm/Xtensive.Orm/Sql/Ddl/Misc/SqlCommandType.cs
+++ b/Orm/Xtensive.Orm/Sql/Ddl/Misc/SqlCommandType.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.08.04
 
-using System;
 
 namespace Xtensive.Sql.Ddl
 {
diff --git a/Orm/Xtensive.Orm/Sql/Ddl/SqlAlterDomain.cs b/Orm/Xtensive.Orm/Sql/Ddl/SqlAlterDomain.cs
index 541782962..1cd24aaa3 100644
--- a/Orm/Xtensive.Orm/Sql/Ddl/SqlAlterDomain.cs
+++ b/Orm/Xtensive.Orm/Sql/Ddl/SqlAlterDomain.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Sql.Model;
 
 namespace Xtensive.Sql.Ddl
diff --git a/Orm/Xtensive.Orm/Sql/Ddl/SqlAlterPartitionFunction.cs b/Orm/Xtensive.Orm/Sql/Ddl/SqlAlterPartitionFunction.cs
index e33de7479..0c2839cdc 100644
--- a/Orm/Xtensive.Orm/Sql/Ddl/SqlAlterPartitionFunction.cs
+++ b/Orm/Xtensive.Orm/Sql/Ddl/SqlAlterPartitionFunction.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Sql.Model;
 
 namespace Xtensive.Sql.Ddl
diff --git a/Orm/Xtensive.Orm/Sql/Ddl/SqlAlterPartitionScheme.cs b/Orm/Xtensive.Orm/Sql/Ddl/SqlAlterPartitionScheme.cs
index 49c5351c3..80049645c 100644
--- a/Orm/Xtensive.Orm/Sql/Ddl/SqlAlterPartitionScheme.cs
+++ b/Orm/Xtensive.Orm/Sql/Ddl/SqlAlterPartitionScheme.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Sql.Model;
 
 namespace Xtensive.Sql.Ddl
diff --git a/Orm/Xtensive.Orm/Sql/Ddl/SqlAlterSequence.cs b/Orm/Xtensive.Orm/Sql/Ddl/SqlAlterSequence.cs
index 81cc21590..e62113bd9 100644
--- a/Orm/Xtensive.Orm/Sql/Ddl/SqlAlterSequence.cs
+++ b/Orm/Xtensive.Orm/Sql/Ddl/SqlAlterSequence.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Sql.Model;
 
 namespace Xtensive.Sql.Ddl
diff --git a/Orm/Xtensive.Orm/Sql/Ddl/SqlAlterTable.cs b/Orm/Xtensive.Orm/Sql/Ddl/SqlAlterTable.cs
index 14922811b..99ddac75a 100644
--- a/Orm/Xtensive.Orm/Sql/Ddl/SqlAlterTable.cs
+++ b/Orm/Xtensive.Orm/Sql/Ddl/SqlAlterTable.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Sql.Model;
 
 namespace Xtensive.Sql.Ddl
diff --git a/Orm/Xtensive.Orm/Sql/Ddl/SqlCommand.cs b/Orm/Xtensive.Orm/Sql/Ddl/SqlCommand.cs
index e45e92e1a..e85b7469e 100644
--- a/Orm/Xtensive.Orm/Sql/Ddl/SqlCommand.cs
+++ b/Orm/Xtensive.Orm/Sql/Ddl/SqlCommand.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.08.04
 
-using System;
 
 namespace Xtensive.Sql.Ddl
 {
diff --git a/Orm/Xtensive.Orm/Sql/Ddl/SqlCreateAssertion.cs b/Orm/Xtensive.Orm/Sql/Ddl/SqlCreateAssertion.cs
index 7337e40a9..41a1647d3 100644
--- a/Orm/Xtensive.Orm/Sql/Ddl/SqlCreateAssertion.cs
+++ b/Orm/Xtensive.Orm/Sql/Ddl/SqlCreateAssertion.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Sql.Model;
 
 namespace Xtensive.Sql.Ddl
diff --git a/Orm/Xtensive.Orm/Sql/Ddl/SqlCreateCharcterSet.cs b/Orm/Xtensive.Orm/Sql/Ddl/SqlCreateCharcterSet.cs
index ebfe7235c..b806917d1 100644
--- a/Orm/Xtensive.Orm/Sql/Ddl/SqlCreateCharcterSet.cs
+++ b/Orm/Xtensive.Orm/Sql/Ddl/SqlCreateCharcterSet.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Sql.Model;
 
 namespace Xtensive.Sql.Ddl
diff --git a/Orm/Xtensive.Orm/Sql/Ddl/SqlCreateCollation.cs b/Orm/Xtensive.Orm/Sql/Ddl/SqlCreateCollation.cs
index e3f64791b..5f1cdfbe0 100644
--- a/Orm/Xtensive.Orm/Sql/Ddl/SqlCreateCollation.cs
+++ b/Orm/Xtensive.Orm/Sql/Ddl/SqlCreateCollation.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Sql.Model;
 
 namespace Xtensive.Sql.Ddl
diff --git a/Orm/Xtensive.Orm/Sql/Ddl/SqlCreateDomain.cs b/Orm/Xtensive.Orm/Sql/Ddl/SqlCreateDomain.cs
index a45ae2d83..19e98cb66 100644
--- a/Orm/Xtensive.Orm/Sql/Ddl/SqlCreateDomain.cs
+++ b/Orm/Xtensive.Orm/Sql/Ddl/SqlCreateDomain.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Sql.Model;
 
 namespace Xtensive.Sql.Ddl
diff --git a/Orm/Xtensive.Orm/Sql/Ddl/SqlCreateIndex.cs b/Orm/Xtensive.Orm/Sql/Ddl/SqlCreateIndex.cs
index 48145b911..e57759fda 100644
--- a/Orm/Xtensive.Orm/Sql/Ddl/SqlCreateIndex.cs
+++ b/Orm/Xtensive.Orm/Sql/Ddl/SqlCreateIndex.cs
@@ -2,7 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
 using Xtensive.Sql.Model;
 using Index = Xtensive.Sql.Model.Index;
 
diff --git a/Orm/Xtensive.Orm/Sql/Ddl/SqlCreatePartitionFunction.cs b/Orm/Xtensive.Orm/Sql/Ddl/SqlCreatePartitionFunction.cs
index 052000a2e..6ee1bab36 100644
--- a/Orm/Xtensive.Orm/Sql/Ddl/SqlCreatePartitionFunction.cs
+++ b/Orm/Xtensive.Orm/Sql/Ddl/SqlCreatePartitionFunction.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Sql.Model;
 
 namespace Xtensive.Sql.Ddl
diff --git a/Orm/Xtensive.Orm/Sql/Ddl/SqlCreatePartitionScheme.cs b/Orm/Xtensive.Orm/Sql/Ddl/SqlCreatePartitionScheme.cs
index 0b67b91f2..360464be0 100644
--- a/Orm/Xtensive.Orm/Sql/Ddl/SqlCreatePartitionScheme.cs
+++ b/Orm/Xtensive.Orm/Sql/Ddl/SqlCreatePartitionScheme.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Sql.Model;
 
 namespace Xtensive.Sql.Ddl
diff --git a/Orm/Xtensive.Orm/Sql/Ddl/SqlCreateSchema.cs b/Orm/Xtensive.Orm/Sql/Ddl/SqlCreateSchema.cs
index 5790a5bca..404100445 100644
--- a/Orm/Xtensive.Orm/Sql/Ddl/SqlCreateSchema.cs
+++ b/Orm/Xtensive.Orm/Sql/Ddl/SqlCreateSchema.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Sql.Model;
 
 namespace Xtensive.Sql.Ddl
diff --git a/Orm/Xtensive.Orm/Sql/Ddl/SqlCreateSequence.cs b/Orm/Xtensive.Orm/Sql/Ddl/SqlCreateSequence.cs
index bd6f2e193..6415b3a0e 100644
--- a/Orm/Xtensive.Orm/Sql/Ddl/SqlCreateSequence.cs
+++ b/Orm/Xtensive.Orm/Sql/Ddl/SqlCreateSequence.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Sql.Model;
 
 namespace Xtensive.Sql.Ddl
diff --git a/Orm/Xtensive.Orm/Sql/Ddl/SqlCreateTable.cs b/Orm/Xtensive.Orm/Sql/Ddl/SqlCreateTable.cs
index 4f1a162c5..43b4ab6e8 100644
--- a/Orm/Xtensive.Orm/Sql/Ddl/SqlCreateTable.cs
+++ b/Orm/Xtensive.Orm/Sql/Ddl/SqlCreateTable.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Sql.Model;
 
 namespace Xtensive.Sql.Ddl
diff --git a/Orm/Xtensive.Orm/Sql/Ddl/SqlCreateTranslation.cs b/Orm/Xtensive.Orm/Sql/Ddl/SqlCreateTranslation.cs
index 69eddc883..aa2a95903 100644
--- a/Orm/Xtensive.Orm/Sql/Ddl/SqlCreateTranslation.cs
+++ b/Orm/Xtensive.Orm/Sql/Ddl/SqlCreateTranslation.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Sql.Model;
 
 namespace Xtensive.Sql.Ddl
diff --git a/Orm/Xtensive.Orm/Sql/Ddl/SqlCreateView.cs b/Orm/Xtensive.Orm/Sql/Ddl/SqlCreateView.cs
index 08d7833ca..9c8aad1fb 100644
--- a/Orm/Xtensive.Orm/Sql/Ddl/SqlCreateView.cs
+++ b/Orm/Xtensive.Orm/Sql/Ddl/SqlCreateView.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Sql.Model;
 
 namespace Xtensive.Sql.Ddl
diff --git a/Orm/Xtensive.Orm/Sql/Ddl/SqlDropAssertion.cs b/Orm/Xtensive.Orm/Sql/Ddl/SqlDropAssertion.cs
index b045504b4..1dfc05e2e 100644
--- a/Orm/Xtensive.Orm/Sql/Ddl/SqlDropAssertion.cs
+++ b/Orm/Xtensive.Orm/Sql/Ddl/SqlDropAssertion.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Sql.Model;
 
 namespace Xtensive.Sql.Ddl
diff --git a/Orm/Xtensive.Orm/Sql/Ddl/SqlDropCharacterSet.cs b/Orm/Xtensive.Orm/Sql/Ddl/SqlDropCharacterSet.cs
index ffdddda61..363123e79 100644
--- a/Orm/Xtensive.Orm/Sql/Ddl/SqlDropCharacterSet.cs
+++ b/Orm/Xtensive.Orm/Sql/Ddl/SqlDropCharacterSet.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Sql.Model;
 
 namespace Xtensive.Sql.Ddl
diff --git a/Orm/Xtensive.Orm/Sql/Ddl/SqlDropCollation.cs b/Orm/Xtensive.Orm/Sql/Ddl/SqlDropCollation.cs
index 555c35eef..26d886569 100644
--- a/Orm/Xtensive.Orm/Sql/Ddl/SqlDropCollation.cs
+++ b/Orm/Xtensive.Orm/Sql/Ddl/SqlDropCollation.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Sql.Model;
 
 namespace Xtensive.Sql.Ddl
diff --git a/Orm/Xtensive.Orm/Sql/Ddl/SqlDropDomain.cs b/Orm/Xtensive.Orm/Sql/Ddl/SqlDropDomain.cs
index a78ff5177..4a105b43c 100644
--- a/Orm/Xtensive.Orm/Sql/Ddl/SqlDropDomain.cs
+++ b/Orm/Xtensive.Orm/Sql/Ddl/SqlDropDomain.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Sql.Model;
 
 namespace Xtensive.Sql.Ddl
diff --git a/Orm/Xtensive.Orm/Sql/Ddl/SqlDropIndex.cs b/Orm/Xtensive.Orm/Sql/Ddl/SqlDropIndex.cs
index cae7ed9e1..529f4936d 100644
--- a/Orm/Xtensive.Orm/Sql/Ddl/SqlDropIndex.cs
+++ b/Orm/Xtensive.Orm/Sql/Ddl/SqlDropIndex.cs
@@ -2,7 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
 using Xtensive.Sql.Model;
 using Index = Xtensive.Sql.Model.Index;
 
diff --git a/Orm/Xtensive.Orm/Sql/Ddl/SqlDropPartitionFunction.cs b/Orm/Xtensive.Orm/Sql/Ddl/SqlDropPartitionFunction.cs
index c015b6195..7aa8e379a 100644
--- a/Orm/Xtensive.Orm/Sql/Ddl/SqlDropPartitionFunction.cs
+++ b/Orm/Xtensive.Orm/Sql/Ddl/SqlDropPartitionFunction.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Sql.Model;
 
 namespace Xtensive.Sql.Ddl
diff --git a/Orm/Xtensive.Orm/Sql/Ddl/SqlDropPartitionScheme.cs b/Orm/Xtensive.Orm/Sql/Ddl/SqlDropPartitionScheme.cs
index e315b7cd7..2937e54b2 100644
--- a/Orm/Xtensive.Orm/Sql/Ddl/SqlDropPartitionScheme.cs
+++ b/Orm/Xtensive.Orm/Sql/Ddl/SqlDropPartitionScheme.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Sql.Model;
 
 namespace Xtensive.Sql.Ddl
diff --git a/Orm/Xtensive.Orm/Sql/Ddl/SqlDropSchema.cs b/Orm/Xtensive.Orm/Sql/Ddl/SqlDropSchema.cs
index b13f79a91..c4c879174 100644
--- a/Orm/Xtensive.Orm/Sql/Ddl/SqlDropSchema.cs
+++ b/Orm/Xtensive.Orm/Sql/Ddl/SqlDropSchema.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Sql.Model;
 
 namespace Xtensive.Sql.Ddl
diff --git a/Orm/Xtensive.Orm/Sql/Ddl/SqlDropSequence.cs b/Orm/Xtensive.Orm/Sql/Ddl/SqlDropSequence.cs
index 04d3d471d..b75a8403d 100644
--- a/Orm/Xtensive.Orm/Sql/Ddl/SqlDropSequence.cs
+++ b/Orm/Xtensive.Orm/Sql/Ddl/SqlDropSequence.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Sql.Model;
 
 namespace Xtensive.Sql.Ddl
diff --git a/Orm/Xtensive.Orm/Sql/Ddl/SqlDropTable.cs b/Orm/Xtensive.Orm/Sql/Ddl/SqlDropTable.cs
index 0d6df7110..61780f4fe 100644
--- a/Orm/Xtensive.Orm/Sql/Ddl/SqlDropTable.cs
+++ b/Orm/Xtensive.Orm/Sql/Ddl/SqlDropTable.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Sql.Model;
 
 namespace Xtensive.Sql.Ddl
diff --git a/Orm/Xtensive.Orm/Sql/Ddl/SqlDropTranslation.cs b/Orm/Xtensive.Orm/Sql/Ddl/SqlDropTranslation.cs
index 533408563..506aacd04 100644
--- a/Orm/Xtensive.Orm/Sql/Ddl/SqlDropTranslation.cs
+++ b/Orm/Xtensive.Orm/Sql/Ddl/SqlDropTranslation.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Sql.Model;
 
 namespace Xtensive.Sql.Ddl
diff --git a/Orm/Xtensive.Orm/Sql/Ddl/SqlDropView.cs b/Orm/Xtensive.Orm/Sql/Ddl/SqlDropView.cs
index 93dd289bf..aa7d6aeec 100644
--- a/Orm/Xtensive.Orm/Sql/Ddl/SqlDropView.cs
+++ b/Orm/Xtensive.Orm/Sql/Ddl/SqlDropView.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Sql.Model;
 
 namespace Xtensive.Sql.Ddl
diff --git a/Orm/Xtensive.Orm/Sql/Ddl/SqlRenameTable.cs b/Orm/Xtensive.Orm/Sql/Ddl/SqlRenameTable.cs
index 5474d4ca4..f277bf527 100644
--- a/Orm/Xtensive.Orm/Sql/Ddl/SqlRenameTable.cs
+++ b/Orm/Xtensive.Orm/Sql/Ddl/SqlRenameTable.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.08.10
 
-using System;
 using Xtensive.Sql.Model;
 
 namespace Xtensive.Sql.Ddl
diff --git a/Orm/Xtensive.Orm/Sql/Ddl/SqlTruncateTable.cs b/Orm/Xtensive.Orm/Sql/Ddl/SqlTruncateTable.cs
index 857b19c9b..115d847af 100755
--- a/Orm/Xtensive.Orm/Sql/Ddl/SqlTruncateTable.cs
+++ b/Orm/Xtensive.Orm/Sql/Ddl/SqlTruncateTable.cs
@@ -2,7 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
 using Xtensive.Sql.Model;
 
 namespace Xtensive.Sql.Ddl
diff --git a/Orm/Xtensive.Orm/Sql/Dml/Collections/SqlColumnCollection.cs b/Orm/Xtensive.Orm/Sql/Dml/Collections/SqlColumnCollection.cs
index 17d856871..1a362fd66 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/Collections/SqlColumnCollection.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/Collections/SqlColumnCollection.cs
@@ -2,9 +2,7 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
 using Xtensive.Core;
 
 
diff --git a/Orm/Xtensive.Orm/Sql/Dml/Collections/SqlInsertValuesCollection.cs b/Orm/Xtensive.Orm/Sql/Dml/Collections/SqlInsertValuesCollection.cs
index 62347d57b..71ddff537 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/Collections/SqlInsertValuesCollection.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/Collections/SqlInsertValuesCollection.cs
@@ -2,10 +2,7 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Core;
 
 namespace Xtensive.Sql.Dml.Collections
diff --git a/Orm/Xtensive.Orm/Sql/Dml/Collections/SqlOrderCollection.cs b/Orm/Xtensive.Orm/Sql/Dml/Collections/SqlOrderCollection.cs
index 4e3dd31af..fb5926329 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/Collections/SqlOrderCollection.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/Collections/SqlOrderCollection.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using System.Collections.ObjectModel;
 
 namespace Xtensive.Sql.Dml
diff --git a/Orm/Xtensive.Orm/Sql/Dml/Collections/SqlTableColumnCollection.cs b/Orm/Xtensive.Orm/Sql/Dml/Collections/SqlTableColumnCollection.cs
index e03d3eaa4..5ce6c1317 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/Collections/SqlTableColumnCollection.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/Collections/SqlTableColumnCollection.cs
@@ -2,9 +2,7 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
 using System.Runtime.CompilerServices;
 
 namespace Xtensive.Sql.Dml
diff --git a/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlAggregate.cs b/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlAggregate.cs
index 860888f7f..d7a9bbe25 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlAggregate.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlAggregate.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Core;
 
 namespace Xtensive.Sql.Dml
diff --git a/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlArray.cs b/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlArray.cs
index 983735ee0..d1f6f50ab 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlArray.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlArray.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.07.13
 
-using System;
 
 namespace Xtensive.Sql.Dml
 {
diff --git a/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlArray{T}.cs b/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlArray{T}.cs
index 7d33b219e..670f3ba5e 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlArray{T}.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlArray{T}.cs
@@ -2,9 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Core;
 
 namespace Xtensive.Sql.Dml
diff --git a/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlBetween.cs b/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlBetween.cs
index fa04b0d05..b986d006a 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlBetween.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlBetween.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Core;
 
 namespace Xtensive.Sql.Dml
diff --git a/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlBinary.cs b/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlBinary.cs
index bfcfe9e69..79061f62f 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlBinary.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlBinary.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Core;
 
 namespace Xtensive.Sql.Dml
diff --git a/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlCase.cs b/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlCase.cs
index 0fd704dfc..9eab2de36 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlCase.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlCase.cs
@@ -2,9 +2,7 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
 using Xtensive.Core;
 
 namespace Xtensive.Sql.Dml
diff --git a/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlCast.cs b/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlCast.cs
index 950a5ec47..7e5965b16 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlCast.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlCast.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Core;
 
 namespace Xtensive.Sql.Dml
diff --git a/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlCollate.cs b/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlCollate.cs
index 7f13e962b..ba9479fb9 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlCollate.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlCollate.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Core;
 using Xtensive.Sql.Model;
 
diff --git a/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlColumn.cs b/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlColumn.cs
index aa2cc9aad..8ced60482 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlColumn.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlColumn.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Core;
 
 namespace Xtensive.Sql.Dml
diff --git a/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlColumnRef.cs b/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlColumnRef.cs
index 6e22a1183..4cead51e5 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlColumnRef.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlColumnRef.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Core;
 
 namespace Xtensive.Sql.Dml
diff --git a/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlColumnStub.cs b/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlColumnStub.cs
index 9de632ef4..f1f57dcc2 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlColumnStub.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlColumnStub.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.09.08
 
-using System;
 
 namespace Xtensive.Sql.Dml
 {
diff --git a/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlComment.cs b/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlComment.cs
index 8f501e8ce..b79f04bef 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlComment.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlComment.cs
@@ -4,7 +4,6 @@
 // Created by: Edgar Isajanyan
 // Created:    2021.09.13
 
-using System;
 using Xtensive.Core;
 
 namespace Xtensive.Sql.Dml
diff --git a/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlConcat.cs b/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlConcat.cs
index cc8eec9be..8186809f9 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlConcat.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlConcat.cs
@@ -4,8 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2009.09.01
 
-using System;
-using System.Collections.Generic;
 using System.Collections.ObjectModel;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlContainer.cs b/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlContainer.cs
index 9e9554c7d..e04fb9bf2 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlContainer.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlContainer.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.06.11
 
-using System;
 using Xtensive.Core;
 
 namespace Xtensive.Sql.Dml
diff --git a/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlCursor.cs b/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlCursor.cs
index cd1b59c6b..81bc1441f 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlCursor.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlCursor.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Core;
 
 namespace Xtensive.Sql.Dml
diff --git a/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlCustomFunctionCall.cs b/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlCustomFunctionCall.cs
index 35ac62ab6..d549e9cd8 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlCustomFunctionCall.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlCustomFunctionCall.cs
@@ -4,10 +4,7 @@
 // Created by: Alena Mikshina
 // Created:    2014.05.06
 
-using System;
-using System.Collections.Generic;
 using System.Collections.ObjectModel;
-using System.Linq;
 using Xtensive.Core;
 
 namespace Xtensive.Sql.Dml
diff --git a/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlDefaultValue.cs b/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlDefaultValue.cs
index b95b79dbf..11f81a953 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlDefaultValue.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlDefaultValue.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Core;
 
 namespace Xtensive.Sql.Dml
diff --git a/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlDynamicFilter.cs b/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlDynamicFilter.cs
index 132a527e6..3f2f984ed 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlDynamicFilter.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlDynamicFilter.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.11.06
 
-using System.Collections.Generic;
 using Xtensive.Core;
 
 namespace Xtensive.Sql.Dml
diff --git a/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlExpression.cs b/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlExpression.cs
index f7a174e5b..fcf3339d7 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlExpression.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlExpression.cs
@@ -2,7 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
 using Xtensive.Core;
 
 namespace Xtensive.Sql.Dml
diff --git a/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlExpressionList.cs b/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlExpressionList.cs
index 16ae8026b..a356a021f 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlExpressionList.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlExpressionList.cs
@@ -5,7 +5,6 @@
 // Created:    2009.09.01
 
 using System.Collections;
-using System.Collections.Generic;
 using Xtensive.Core;
 
 namespace Xtensive.Sql.Dml
diff --git a/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlExtract.cs b/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlExtract.cs
index c5ee6c3a7..9eb8206ef 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlExtract.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlExtract.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.07.24
 
-using System;
 using System.Diagnostics;
 using System.Reflection;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlFunctionCall.cs b/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlFunctionCall.cs
index 3801322b4..e3c0dd6be 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlFunctionCall.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlFunctionCall.cs
@@ -2,10 +2,7 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Collections.Generic;
 using System.Collections.ObjectModel;
-using System.Linq;
 using Xtensive.Core;
 
 namespace Xtensive.Sql.Dml
diff --git a/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlFunctionCallBase.cs b/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlFunctionCallBase.cs
index 680fb1c61..62310719c 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlFunctionCallBase.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlFunctionCallBase.cs
@@ -2,10 +2,7 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Collections.Generic;
 using System.Collections.ObjectModel;
-using System.Linq;
 using Xtensive.Core;
 
 namespace Xtensive.Sql.Dml
diff --git a/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlLike.cs b/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlLike.cs
index d8892e0a0..4e8fcbe53 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlLike.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlLike.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Core;
 
 namespace Xtensive.Sql.Dml
diff --git a/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlLiteral.cs b/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlLiteral.cs
index 95b6815fe..87b2d60fd 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlLiteral.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlLiteral.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.07.13
 
-using System;
 
 namespace Xtensive.Sql.Dml
 {
diff --git a/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlLiteral{T}.cs b/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlLiteral{T}.cs
index 6dae46acb..9b91ff5d6 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlLiteral{T}.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlLiteral{T}.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Core;
 
 namespace Xtensive.Sql.Dml
diff --git a/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlMatch.cs b/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlMatch.cs
index 602860db9..cd82d19da 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlMatch.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlMatch.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Core;
 
 namespace Xtensive.Sql.Dml
diff --git a/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlNative.cs b/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlNative.cs
index 26d7e11cb..b50e95349 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlNative.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlNative.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Core;
 
 namespace Xtensive.Sql.Dml
diff --git a/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlNextValue.cs b/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlNextValue.cs
index 7d4f714b9..b8863b525 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlNextValue.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlNextValue.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Core;
 using Xtensive.Sql.Model;
 
diff --git a/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlNull.cs b/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlNull.cs
index 9dfade610..1af0c395c 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlNull.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlNull.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Core;
 
 namespace Xtensive.Sql.Dml
diff --git a/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlParameterRef.cs b/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlParameterRef.cs
index 922305ac6..4aacbce91 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlParameterRef.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlParameterRef.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Core;
 
 namespace Xtensive.Sql.Dml
diff --git a/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlRound.cs b/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlRound.cs
index cf2a47879..4b53e2808 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlRound.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlRound.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.08.03
 
-using System;
 using Xtensive.Core;
 
 namespace Xtensive.Sql.Dml
diff --git a/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlRow.cs b/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlRow.cs
index d3058bedb..733d161fc 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlRow.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlRow.cs
@@ -2,8 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
-using System.Collections.Generic;
 using System.Collections.ObjectModel;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlSubQuery.cs b/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlSubQuery.cs
index d8cefb1d2..0b610d28e 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlSubQuery.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlSubQuery.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Core;
 
 namespace Xtensive.Sql.Dml
diff --git a/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlTableColumn.cs b/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlTableColumn.cs
index ee2d31dc7..41a8293fb 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlTableColumn.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlTableColumn.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Core;
 using Xtensive.Sql.Model;
 
diff --git a/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlTrim.cs b/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlTrim.cs
index 038b1424b..f2668d6eb 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlTrim.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlTrim.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Core;
 
 namespace Xtensive.Sql.Dml
diff --git a/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlUnary.cs b/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlUnary.cs
index cf6405563..e103cfdfa 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlUnary.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlUnary.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Core;
 
 namespace Xtensive.Sql.Dml
diff --git a/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlUserColumn.cs b/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlUserColumn.cs
index d439fabfe..d2cbfab6e 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlUserColumn.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlUserColumn.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Core;
 
 namespace Xtensive.Sql.Dml
diff --git a/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlUserFunctionCall.cs b/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlUserFunctionCall.cs
index 980c3e4e8..af2447011 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlUserFunctionCall.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlUserFunctionCall.cs
@@ -2,10 +2,7 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Collections.Generic;
 using System.Collections.ObjectModel;
-using System.Linq;
 using Xtensive.Core;
 
 namespace Xtensive.Sql.Dml
diff --git a/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlVariable.cs b/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlVariable.cs
index fc0532183..182b3a261 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlVariable.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/Expressions/SqlVariable.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Core;
 
 namespace Xtensive.Sql.Dml
diff --git a/Orm/Xtensive.Orm/Sql/Dml/Extensions.cs b/Orm/Xtensive.Orm/Sql/Dml/Extensions.cs
index 6f5075247..5c89fd5d3 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/Extensions.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/Extensions.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.08.24
 
-using System;
 using System.Text;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Sql/Dml/Hints/SqlFastFirstRowsHint.cs b/Orm/Xtensive.Orm/Sql/Dml/Hints/SqlFastFirstRowsHint.cs
index 005a21d50..164c22773 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/Hints/SqlFastFirstRowsHint.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/Hints/SqlFastFirstRowsHint.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 
 namespace Xtensive.Sql.Dml
 {
diff --git a/Orm/Xtensive.Orm/Sql/Dml/Hints/SqlForceJoinOrderHint.cs b/Orm/Xtensive.Orm/Sql/Dml/Hints/SqlForceJoinOrderHint.cs
index df69681df..c54278a1d 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/Hints/SqlForceJoinOrderHint.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/Hints/SqlForceJoinOrderHint.cs
@@ -2,9 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
-using System.Linq;
-using System.Collections.Generic;
 using Xtensive.Core;
 
 namespace Xtensive.Sql.Dml
diff --git a/Orm/Xtensive.Orm/Sql/Dml/Hints/SqlHint.cs b/Orm/Xtensive.Orm/Sql/Dml/Hints/SqlHint.cs
index 0604b8456..7c7b9adf7 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/Hints/SqlHint.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/Hints/SqlHint.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 
 namespace Xtensive.Sql.Dml
 {
diff --git a/Orm/Xtensive.Orm/Sql/Dml/Hints/SqlJoinHint.cs b/Orm/Xtensive.Orm/Sql/Dml/Hints/SqlJoinHint.cs
index 0a03a6478..40ffd72d2 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/Hints/SqlJoinHint.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/Hints/SqlJoinHint.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 
 namespace Xtensive.Sql.Dml
 {
diff --git a/Orm/Xtensive.Orm/Sql/Dml/Hints/SqlJoinMethod.cs b/Orm/Xtensive.Orm/Sql/Dml/Hints/SqlJoinMethod.cs
index 07eb3f709..8ce0a3c5a 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/Hints/SqlJoinMethod.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/Hints/SqlJoinMethod.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 
 namespace Xtensive.Sql.Dml
 {
diff --git a/Orm/Xtensive.Orm/Sql/Dml/Hints/SqlNativeHint.cs b/Orm/Xtensive.Orm/Sql/Dml/Hints/SqlNativeHint.cs
index 3334f448e..fa28f5829 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/Hints/SqlNativeHint.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/Hints/SqlNativeHint.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 
 namespace Xtensive.Sql.Dml
 {
diff --git a/Orm/Xtensive.Orm/Sql/Dml/SqlContainsTable.cs b/Orm/Xtensive.Orm/Sql/Dml/SqlContainsTable.cs
index e2d84cb17..9940e81c8 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/SqlContainsTable.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/SqlContainsTable.cs
@@ -1,6 +1,3 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Collections;
 using Xtensive.Sql.Model;
 
diff --git a/Orm/Xtensive.Orm/Sql/Dml/SqlCustomFunctionType.cs b/Orm/Xtensive.Orm/Sql/Dml/SqlCustomFunctionType.cs
index 5f2798c77..35c427fa0 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/SqlCustomFunctionType.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/SqlCustomFunctionType.cs
@@ -4,7 +4,6 @@
 // Created by: Alena Mikshina
 // Created:    2014.05.06
 
-using System;
 using Xtensive.Core;
 
 namespace Xtensive.Sql.Dml
diff --git a/Orm/Xtensive.Orm/Sql/Dml/SqlDatePart.cs b/Orm/Xtensive.Orm/Sql/Dml/SqlDatePart.cs
index 9a80a01cf..5e9b40413 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/SqlDatePart.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/SqlDatePart.cs
@@ -2,7 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
 
 namespace Xtensive.Sql.Dml
 {
diff --git a/Orm/Xtensive.Orm/Sql/Dml/SqlDateTimeOffsetPart.cs b/Orm/Xtensive.Orm/Sql/Dml/SqlDateTimeOffsetPart.cs
index c1d0b61a9..3b3dbbd7f 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/SqlDateTimeOffsetPart.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/SqlDateTimeOffsetPart.cs
@@ -2,7 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
 
 namespace Xtensive.Sql.Dml
 {
diff --git a/Orm/Xtensive.Orm/Sql/Dml/SqlDateTimePart.cs b/Orm/Xtensive.Orm/Sql/Dml/SqlDateTimePart.cs
index e431858e0..9abaef0c7 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/SqlDateTimePart.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/SqlDateTimePart.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 
 namespace Xtensive.Sql.Dml
 {
diff --git a/Orm/Xtensive.Orm/Sql/Dml/SqlFetchOption.cs b/Orm/Xtensive.Orm/Sql/Dml/SqlFetchOption.cs
index 2d7b4523d..ea0ee6810 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/SqlFetchOption.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/SqlFetchOption.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 
 namespace Xtensive.Sql.Dml
 {
diff --git a/Orm/Xtensive.Orm/Sql/Dml/SqlFreeTextTable.cs b/Orm/Xtensive.Orm/Sql/Dml/SqlFreeTextTable.cs
index 4dcb18621..b31a92f7a 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/SqlFreeTextTable.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/SqlFreeTextTable.cs
@@ -4,9 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2009.12.29
 
-using System;
-using System.Linq;
-using System.Collections.Generic;
 using Xtensive.Collections;
 using Xtensive.Sql.Model;
 
diff --git a/Orm/Xtensive.Orm/Sql/Dml/SqlFunctionType.cs b/Orm/Xtensive.Orm/Sql/Dml/SqlFunctionType.cs
index a54c7e045..ca407697c 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/SqlFunctionType.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/SqlFunctionType.cs
@@ -2,7 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
 
 namespace Xtensive.Sql.Dml
 {
diff --git a/Orm/Xtensive.Orm/Sql/Dml/SqlIntervalPart.cs b/Orm/Xtensive.Orm/Sql/Dml/SqlIntervalPart.cs
index 45e6a7dbb..24cd1a6e3 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/SqlIntervalPart.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/SqlIntervalPart.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.02.25
 
-using System;
 
 namespace Xtensive.Sql.Dml
 {
diff --git a/Orm/Xtensive.Orm/Sql/Dml/SqlJoinExpression.cs b/Orm/Xtensive.Orm/Sql/Dml/SqlJoinExpression.cs
index 5c0cb9193..e147ca940 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/SqlJoinExpression.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/SqlJoinExpression.cs
@@ -2,8 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
-using System.Collections.Generic;
 
 namespace Xtensive.Sql.Dml
 {
diff --git a/Orm/Xtensive.Orm/Sql/Dml/SqlJoinType.cs b/Orm/Xtensive.Orm/Sql/Dml/SqlJoinType.cs
index 26c9be593..b07059f9b 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/SqlJoinType.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/SqlJoinType.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 
 namespace Xtensive.Sql.Dml
 {
diff --git a/Orm/Xtensive.Orm/Sql/Dml/SqlJoinedTable.cs b/Orm/Xtensive.Orm/Sql/Dml/SqlJoinedTable.cs
index 28809f0ef..7847f5126 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/SqlJoinedTable.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/SqlJoinedTable.cs
@@ -2,8 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
-using System.Collections.Generic;
 
 namespace Xtensive.Sql.Dml
 {
diff --git a/Orm/Xtensive.Orm/Sql/Dml/SqlLockType.cs b/Orm/Xtensive.Orm/Sql/Dml/SqlLockType.cs
index a97c27a46..24ec0b967 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/SqlLockType.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/SqlLockType.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.08.24
 
-using System;
 
 namespace Xtensive.Sql.Dml
 {
diff --git a/Orm/Xtensive.Orm/Sql/Dml/SqlMatchType.cs b/Orm/Xtensive.Orm/Sql/Dml/SqlMatchType.cs
index abdc1feac..f3630c5c2 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/SqlMatchType.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/SqlMatchType.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 
 namespace Xtensive.Sql.Dml
 {
diff --git a/Orm/Xtensive.Orm/Sql/Dml/SqlOrder.cs b/Orm/Xtensive.Orm/Sql/Dml/SqlOrder.cs
index 4190c3540..df38c3b3d 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/SqlOrder.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/SqlOrder.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 
 namespace Xtensive.Sql.Dml
 {
diff --git a/Orm/Xtensive.Orm/Sql/Dml/SqlQueryRef.cs b/Orm/Xtensive.Orm/Sql/Dml/SqlQueryRef.cs
index e518a5eb2..352eecf10 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/SqlQueryRef.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/SqlQueryRef.cs
@@ -2,9 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 
 namespace Xtensive.Sql.Dml
 {
diff --git a/Orm/Xtensive.Orm/Sql/Dml/SqlTable.cs b/Orm/Xtensive.Orm/Sql/Dml/SqlTable.cs
index ad33aa675..9ad3fd619 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/SqlTable.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/SqlTable.cs
@@ -2,9 +2,7 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
 using Xtensive.Sql.Model;
 
 namespace Xtensive.Sql.Dml
diff --git a/Orm/Xtensive.Orm/Sql/Dml/SqlTableRef.cs b/Orm/Xtensive.Orm/Sql/Dml/SqlTableRef.cs
index 5046adb0b..93d8c054d 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/SqlTableRef.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/SqlTableRef.cs
@@ -2,9 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
-using System.Linq;
-using System.Collections.Generic;
 using System.Collections.ObjectModel;
 using Xtensive.Collections;
 using Xtensive.Sql.Model;
diff --git a/Orm/Xtensive.Orm/Sql/Dml/SqlTimePart.cs b/Orm/Xtensive.Orm/Sql/Dml/SqlTimePart.cs
index 87923501a..8c4d2c7fa 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/SqlTimePart.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/SqlTimePart.cs
@@ -2,7 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
 
 namespace Xtensive.Sql.Dml
 {
diff --git a/Orm/Xtensive.Orm/Sql/Dml/SqlTrimType.cs b/Orm/Xtensive.Orm/Sql/Dml/SqlTrimType.cs
index 9fb89bb6d..03a906097 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/SqlTrimType.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/SqlTrimType.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 
 namespace Xtensive.Sql.Dml
 {
diff --git a/Orm/Xtensive.Orm/Sql/Dml/Statements/SqlAssignment.cs b/Orm/Xtensive.Orm/Sql/Dml/Statements/SqlAssignment.cs
index 48df59268..f8de3f75c 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/Statements/SqlAssignment.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/Statements/SqlAssignment.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 
 namespace Xtensive.Sql.Dml
 {
diff --git a/Orm/Xtensive.Orm/Sql/Dml/Statements/SqlBatch.cs b/Orm/Xtensive.Orm/Sql/Dml/Statements/SqlBatch.cs
index 0dc6a9075..ff06a870a 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/Statements/SqlBatch.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/Statements/SqlBatch.cs
@@ -2,9 +2,7 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
 using System.Collections.ObjectModel;
 
 namespace Xtensive.Sql.Dml
diff --git a/Orm/Xtensive.Orm/Sql/Dml/Statements/SqlBreak.cs b/Orm/Xtensive.Orm/Sql/Dml/Statements/SqlBreak.cs
index 43fa616ea..ca42e547f 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/Statements/SqlBreak.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/Statements/SqlBreak.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 
 namespace Xtensive.Sql.Dml
 {
diff --git a/Orm/Xtensive.Orm/Sql/Dml/Statements/SqlCloseCursor.cs b/Orm/Xtensive.Orm/Sql/Dml/Statements/SqlCloseCursor.cs
index 6cbedc1c7..bdc1890ff 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/Statements/SqlCloseCursor.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/Statements/SqlCloseCursor.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 
 namespace Xtensive.Sql.Dml
 {
diff --git a/Orm/Xtensive.Orm/Sql/Dml/Statements/SqlContinue.cs b/Orm/Xtensive.Orm/Sql/Dml/Statements/SqlContinue.cs
index 3b1ef9a5c..970c2ff89 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/Statements/SqlContinue.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/Statements/SqlContinue.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 
 namespace Xtensive.Sql.Dml
 {
diff --git a/Orm/Xtensive.Orm/Sql/Dml/Statements/SqlDeclareCursor.cs b/Orm/Xtensive.Orm/Sql/Dml/Statements/SqlDeclareCursor.cs
index 9508ff5be..24c24339d 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/Statements/SqlDeclareCursor.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/Statements/SqlDeclareCursor.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 
 namespace Xtensive.Sql.Dml
 {
diff --git a/Orm/Xtensive.Orm/Sql/Dml/Statements/SqlDeclareVariable.cs b/Orm/Xtensive.Orm/Sql/Dml/Statements/SqlDeclareVariable.cs
index d7aa658f9..66bd2507e 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/Statements/SqlDeclareVariable.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/Statements/SqlDeclareVariable.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 
 namespace Xtensive.Sql.Dml
 {
diff --git a/Orm/Xtensive.Orm/Sql/Dml/Statements/SqlDelete.cs b/Orm/Xtensive.Orm/Sql/Dml/Statements/SqlDelete.cs
index 658b98a96..15fb7cba1 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/Statements/SqlDelete.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/Statements/SqlDelete.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 
 namespace Xtensive.Sql.Dml
 {
diff --git a/Orm/Xtensive.Orm/Sql/Dml/Statements/SqlFetch.cs b/Orm/Xtensive.Orm/Sql/Dml/Statements/SqlFetch.cs
index 84adf61b2..0bfe5352d 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/Statements/SqlFetch.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/Statements/SqlFetch.cs
@@ -2,8 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
-using System.Collections.Generic;
 using System.Collections.ObjectModel;
 
 namespace Xtensive.Sql.Dml
diff --git a/Orm/Xtensive.Orm/Sql/Dml/Statements/SqlIf.cs b/Orm/Xtensive.Orm/Sql/Dml/Statements/SqlIf.cs
index ea2bbee21..1136746f3 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/Statements/SqlIf.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/Statements/SqlIf.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Core;
 
 namespace Xtensive.Sql.Dml
diff --git a/Orm/Xtensive.Orm/Sql/Dml/Statements/SqlInsert.cs b/Orm/Xtensive.Orm/Sql/Dml/Statements/SqlInsert.cs
index 31c8df652..4a20f9ba8 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/Statements/SqlInsert.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/Statements/SqlInsert.cs
@@ -2,9 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Sql.Dml.Collections;
 
 namespace Xtensive.Sql.Dml
diff --git a/Orm/Xtensive.Orm/Sql/Dml/Statements/SqlOpenCursor.cs b/Orm/Xtensive.Orm/Sql/Dml/Statements/SqlOpenCursor.cs
index ba33a97af..36644b31b 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/Statements/SqlOpenCursor.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/Statements/SqlOpenCursor.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 
 namespace Xtensive.Sql.Dml
 {
diff --git a/Orm/Xtensive.Orm/Sql/Dml/Statements/SqlQueryExpression.cs b/Orm/Xtensive.Orm/Sql/Dml/Statements/SqlQueryExpression.cs
index 4db55cfc4..d24be287c 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/Statements/SqlQueryExpression.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/Statements/SqlQueryExpression.cs
@@ -2,9 +2,7 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
 
 namespace Xtensive.Sql.Dml
 {
diff --git a/Orm/Xtensive.Orm/Sql/Dml/Statements/SqlQueryStatement.cs b/Orm/Xtensive.Orm/Sql/Dml/Statements/SqlQueryStatement.cs
index 81a13268f..b27f53053 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/Statements/SqlQueryStatement.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/Statements/SqlQueryStatement.cs
@@ -2,8 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
-using System.Collections.Generic;
 using System.Collections.ObjectModel;
 
 namespace Xtensive.Sql.Dml
diff --git a/Orm/Xtensive.Orm/Sql/Dml/Statements/SqlSelect.cs b/Orm/Xtensive.Orm/Sql/Dml/Statements/SqlSelect.cs
index d4ea0f54a..9ae76d678 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/Statements/SqlSelect.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/Statements/SqlSelect.cs
@@ -2,9 +2,7 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
 
 namespace Xtensive.Sql.Dml
 {
diff --git a/Orm/Xtensive.Orm/Sql/Dml/Statements/SqlStatementBlock.cs b/Orm/Xtensive.Orm/Sql/Dml/Statements/SqlStatementBlock.cs
index 7adecc9d1..7ce1ad75d 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/Statements/SqlStatementBlock.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/Statements/SqlStatementBlock.cs
@@ -2,9 +2,7 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
 using System.Collections.ObjectModel;
 
 namespace Xtensive.Sql.Dml
diff --git a/Orm/Xtensive.Orm/Sql/Dml/Statements/SqlUpdate.cs b/Orm/Xtensive.Orm/Sql/Dml/Statements/SqlUpdate.cs
index a0b0c6245..e89056543 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/Statements/SqlUpdate.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/Statements/SqlUpdate.cs
@@ -2,8 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
-using System.Collections.Generic;
 
 namespace Xtensive.Sql.Dml
 {
diff --git a/Orm/Xtensive.Orm/Sql/Dml/Statements/SqlWhile.cs b/Orm/Xtensive.Orm/Sql/Dml/Statements/SqlWhile.cs
index 2b0a64748..2cd2a3304 100644
--- a/Orm/Xtensive.Orm/Sql/Dml/Statements/SqlWhile.cs
+++ b/Orm/Xtensive.Orm/Sql/Dml/Statements/SqlWhile.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Core;
 
 namespace Xtensive.Sql.Dml
diff --git a/Orm/Xtensive.Orm/Sql/Info/ColumnFeatures.cs b/Orm/Xtensive.Orm/Sql/Info/ColumnFeatures.cs
index c92ec959b..e3a017866 100644
--- a/Orm/Xtensive.Orm/Sql/Info/ColumnFeatures.cs
+++ b/Orm/Xtensive.Orm/Sql/Info/ColumnFeatures.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 
 namespace Xtensive.Sql.Info
 {
diff --git a/Orm/Xtensive.Orm/Sql/Info/ColumnInfo.cs b/Orm/Xtensive.Orm/Sql/Info/ColumnInfo.cs
index 00a4d2831..db8d7849c 100644
--- a/Orm/Xtensive.Orm/Sql/Info/ColumnInfo.cs
+++ b/Orm/Xtensive.Orm/Sql/Info/ColumnInfo.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Core;
 
 namespace Xtensive.Sql.Info
diff --git a/Orm/Xtensive.Orm/Sql/Info/Constaints/CheckConstraintFeatures.cs b/Orm/Xtensive.Orm/Sql/Info/Constaints/CheckConstraintFeatures.cs
index 858c83e2c..c13e256c7 100644
--- a/Orm/Xtensive.Orm/Sql/Info/Constaints/CheckConstraintFeatures.cs
+++ b/Orm/Xtensive.Orm/Sql/Info/Constaints/CheckConstraintFeatures.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.07.20
 
-using System;
 
 namespace Xtensive.Sql.Info
 {
diff --git a/Orm/Xtensive.Orm/Sql/Info/Constaints/CheckConstraintInfo.cs b/Orm/Xtensive.Orm/Sql/Info/Constaints/CheckConstraintInfo.cs
index 58ca7b791..5ebbcd964 100644
--- a/Orm/Xtensive.Orm/Sql/Info/Constaints/CheckConstraintInfo.cs
+++ b/Orm/Xtensive.Orm/Sql/Info/Constaints/CheckConstraintInfo.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Core;
 
 namespace Xtensive.Sql.Info
diff --git a/Orm/Xtensive.Orm/Sql/Info/Constaints/ForeignKeyConstraintActions.cs b/Orm/Xtensive.Orm/Sql/Info/Constaints/ForeignKeyConstraintActions.cs
index b9c32a9e1..3da719dc6 100644
--- a/Orm/Xtensive.Orm/Sql/Info/Constaints/ForeignKeyConstraintActions.cs
+++ b/Orm/Xtensive.Orm/Sql/Info/Constaints/ForeignKeyConstraintActions.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 
 namespace Xtensive.Sql.Info
 {
diff --git a/Orm/Xtensive.Orm/Sql/Info/Constaints/ForeignKeyConstraintFeatures.cs b/Orm/Xtensive.Orm/Sql/Info/Constaints/ForeignKeyConstraintFeatures.cs
index 4ca5442c9..223848047 100644
--- a/Orm/Xtensive.Orm/Sql/Info/Constaints/ForeignKeyConstraintFeatures.cs
+++ b/Orm/Xtensive.Orm/Sql/Info/Constaints/ForeignKeyConstraintFeatures.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.07.20
 
-using System;
 using System.Diagnostics;
 
 namespace Xtensive.Sql.Info
diff --git a/Orm/Xtensive.Orm/Sql/Info/Constaints/ForeignKeyConstraintInfo.cs b/Orm/Xtensive.Orm/Sql/Info/Constaints/ForeignKeyConstraintInfo.cs
index 127127e97..0be608dc4 100644
--- a/Orm/Xtensive.Orm/Sql/Info/Constaints/ForeignKeyConstraintInfo.cs
+++ b/Orm/Xtensive.Orm/Sql/Info/Constaints/ForeignKeyConstraintInfo.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Core;
 
 namespace Xtensive.Sql.Info
diff --git a/Orm/Xtensive.Orm/Sql/Info/Constaints/PrimaryKeyConstraintFeatures.cs b/Orm/Xtensive.Orm/Sql/Info/Constaints/PrimaryKeyConstraintFeatures.cs
index d5b16591d..2992e7d47 100644
--- a/Orm/Xtensive.Orm/Sql/Info/Constaints/PrimaryKeyConstraintFeatures.cs
+++ b/Orm/Xtensive.Orm/Sql/Info/Constaints/PrimaryKeyConstraintFeatures.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.07.20
 
-using System;
 
 namespace Xtensive.Sql.Info
 {
diff --git a/Orm/Xtensive.Orm/Sql/Info/Constaints/UniqueConstraintFeatures.cs b/Orm/Xtensive.Orm/Sql/Info/Constaints/UniqueConstraintFeatures.cs
index f33c25986..997436482 100644
--- a/Orm/Xtensive.Orm/Sql/Info/Constaints/UniqueConstraintFeatures.cs
+++ b/Orm/Xtensive.Orm/Sql/Info/Constaints/UniqueConstraintFeatures.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.07.20
 
-using System;
 
 namespace Xtensive.Sql.Info
 {
diff --git a/Orm/Xtensive.Orm/Sql/Info/CoreServerInfo.cs b/Orm/Xtensive.Orm/Sql/Info/CoreServerInfo.cs
index b08f38501..fc2d90725 100644
--- a/Orm/Xtensive.Orm/Sql/Info/CoreServerInfo.cs
+++ b/Orm/Xtensive.Orm/Sql/Info/CoreServerInfo.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.12.25
 
-using System;
 using Xtensive.Core;
 
 namespace Xtensive.Sql.Info
diff --git a/Orm/Xtensive.Orm/Sql/Info/DataTypeCollection.cs b/Orm/Xtensive.Orm/Sql/Info/DataTypeCollection.cs
index 4ed8885b9..3920861d6 100644
--- a/Orm/Xtensive.Orm/Sql/Info/DataTypeCollection.cs
+++ b/Orm/Xtensive.Orm/Sql/Info/DataTypeCollection.cs
@@ -2,9 +2,7 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
 using Xtensive.Core;
 
 namespace Xtensive.Sql.Info
diff --git a/Orm/Xtensive.Orm/Sql/Info/DataTypeFeatures.cs b/Orm/Xtensive.Orm/Sql/Info/DataTypeFeatures.cs
index 252440a47..5d71ad26f 100644
--- a/Orm/Xtensive.Orm/Sql/Info/DataTypeFeatures.cs
+++ b/Orm/Xtensive.Orm/Sql/Info/DataTypeFeatures.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 
 namespace Xtensive.Sql.Info
 {
diff --git a/Orm/Xtensive.Orm/Sql/Info/DataTypeInfo.cs b/Orm/Xtensive.Orm/Sql/Info/DataTypeInfo.cs
index 23cacaa9c..19c483152 100644
--- a/Orm/Xtensive.Orm/Sql/Info/DataTypeInfo.cs
+++ b/Orm/Xtensive.Orm/Sql/Info/DataTypeInfo.cs
@@ -2,8 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
-using System.Collections.Generic;
 using Xtensive.Collections;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Sql/Info/DdlStatements.cs b/Orm/Xtensive.Orm/Sql/Info/DdlStatements.cs
index f76cf9306..7f62d2925 100644
--- a/Orm/Xtensive.Orm/Sql/Info/DdlStatements.cs
+++ b/Orm/Xtensive.Orm/Sql/Info/DdlStatements.cs
@@ -2,7 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
 
 namespace Xtensive.Sql.Info
 {
diff --git a/Orm/Xtensive.Orm/Sql/Info/FeaturesExtensions.cs b/Orm/Xtensive.Orm/Sql/Info/FeaturesExtensions.cs
index 04dd1c8fa..ba3679372 100644
--- a/Orm/Xtensive.Orm/Sql/Info/FeaturesExtensions.cs
+++ b/Orm/Xtensive.Orm/Sql/Info/FeaturesExtensions.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.07.15
 
-using System;
 
 namespace Xtensive.Sql.Info
 {
diff --git a/Orm/Xtensive.Orm/Sql/Info/FullTextSearchInfo.cs b/Orm/Xtensive.Orm/Sql/Info/FullTextSearchInfo.cs
index c3d1b52a6..344080a13 100644
--- a/Orm/Xtensive.Orm/Sql/Info/FullTextSearchInfo.cs
+++ b/Orm/Xtensive.Orm/Sql/Info/FullTextSearchInfo.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Core;
 
 namespace Xtensive.Sql.Info
diff --git a/Orm/Xtensive.Orm/Sql/Info/IdentityFeatures.cs b/Orm/Xtensive.Orm/Sql/Info/IdentityFeatures.cs
index 0876e94ff..77d0a8920 100644
--- a/Orm/Xtensive.Orm/Sql/Info/IdentityFeatures.cs
+++ b/Orm/Xtensive.Orm/Sql/Info/IdentityFeatures.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 
 namespace Xtensive.Sql.Info
 {
diff --git a/Orm/Xtensive.Orm/Sql/Info/IndexFeatures.cs b/Orm/Xtensive.Orm/Sql/Info/IndexFeatures.cs
index f955b75f5..fa9bd7ef1 100644
--- a/Orm/Xtensive.Orm/Sql/Info/IndexFeatures.cs
+++ b/Orm/Xtensive.Orm/Sql/Info/IndexFeatures.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 
 namespace Xtensive.Sql.Info
 {
diff --git a/Orm/Xtensive.Orm/Sql/Info/IndexInfo.cs b/Orm/Xtensive.Orm/Sql/Info/IndexInfo.cs
index 6a9e1c330..7f56c38dd 100644
--- a/Orm/Xtensive.Orm/Sql/Info/IndexInfo.cs
+++ b/Orm/Xtensive.Orm/Sql/Info/IndexInfo.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Core;
 
 namespace Xtensive.Sql.Info
diff --git a/Orm/Xtensive.Orm/Sql/Info/IsolationLevels.cs b/Orm/Xtensive.Orm/Sql/Info/IsolationLevels.cs
index 2532baad4..d29e8c231 100644
--- a/Orm/Xtensive.Orm/Sql/Info/IsolationLevels.cs
+++ b/Orm/Xtensive.Orm/Sql/Info/IsolationLevels.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 
 namespace Xtensive.Sql.Info
 {
diff --git a/Orm/Xtensive.Orm/Sql/Info/PartitionMethods.cs b/Orm/Xtensive.Orm/Sql/Info/PartitionMethods.cs
index a246b6f42..685806b91 100644
--- a/Orm/Xtensive.Orm/Sql/Info/PartitionMethods.cs
+++ b/Orm/Xtensive.Orm/Sql/Info/PartitionMethods.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 
 namespace Xtensive.Sql.Info
 {
diff --git a/Orm/Xtensive.Orm/Sql/Info/QueryFeatures.cs b/Orm/Xtensive.Orm/Sql/Info/QueryFeatures.cs
index 76773ed2d..6f79eb99a 100644
--- a/Orm/Xtensive.Orm/Sql/Info/QueryFeatures.cs
+++ b/Orm/Xtensive.Orm/Sql/Info/QueryFeatures.cs
@@ -2,7 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
 
 namespace Xtensive.Sql.Info
 {
diff --git a/Orm/Xtensive.Orm/Sql/Info/QueryInfo.cs b/Orm/Xtensive.Orm/Sql/Info/QueryInfo.cs
index 143253c7f..b16441994 100644
--- a/Orm/Xtensive.Orm/Sql/Info/QueryInfo.cs
+++ b/Orm/Xtensive.Orm/Sql/Info/QueryInfo.cs
@@ -2,7 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
 using Xtensive.Core;
 
 namespace Xtensive.Sql.Info
diff --git a/Orm/Xtensive.Orm/Sql/Info/SequenceFeatures.cs b/Orm/Xtensive.Orm/Sql/Info/SequenceFeatures.cs
index f07dc9c6a..80b30f528 100644
--- a/Orm/Xtensive.Orm/Sql/Info/SequenceFeatures.cs
+++ b/Orm/Xtensive.Orm/Sql/Info/SequenceFeatures.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 
 namespace Xtensive.Sql.Info
 {
diff --git a/Orm/Xtensive.Orm/Sql/Info/SequenceInfo.cs b/Orm/Xtensive.Orm/Sql/Info/SequenceInfo.cs
index aab12fe5f..03914805c 100644
--- a/Orm/Xtensive.Orm/Sql/Info/SequenceInfo.cs
+++ b/Orm/Xtensive.Orm/Sql/Info/SequenceInfo.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Core;
 
 namespace Xtensive.Sql.Info
diff --git a/Orm/Xtensive.Orm/Sql/Info/ServerFeatures.cs b/Orm/Xtensive.Orm/Sql/Info/ServerFeatures.cs
index 684308c5b..8b0023e8c 100644
--- a/Orm/Xtensive.Orm/Sql/Info/ServerFeatures.cs
+++ b/Orm/Xtensive.Orm/Sql/Info/ServerFeatures.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2010.02.05
 
-using System;
 using System.Diagnostics;
 
 namespace Xtensive.Sql.Info
diff --git a/Orm/Xtensive.Orm/Sql/Info/TableInfo.cs b/Orm/Xtensive.Orm/Sql/Info/TableInfo.cs
index bb521b3e1..68330c2b2 100644
--- a/Orm/Xtensive.Orm/Sql/Info/TableInfo.cs
+++ b/Orm/Xtensive.Orm/Sql/Info/TableInfo.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Core;
 
 namespace Xtensive.Sql.Info
diff --git a/Orm/Xtensive.Orm/Sql/Info/TemporaryTableFeatures.cs b/Orm/Xtensive.Orm/Sql/Info/TemporaryTableFeatures.cs
index 9df1a79ca..4c039035e 100644
--- a/Orm/Xtensive.Orm/Sql/Info/TemporaryTableFeatures.cs
+++ b/Orm/Xtensive.Orm/Sql/Info/TemporaryTableFeatures.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 
 namespace Xtensive.Sql.Info
 {
diff --git a/Orm/Xtensive.Orm/Sql/Info/TemporaryTableInfo.cs b/Orm/Xtensive.Orm/Sql/Info/TemporaryTableInfo.cs
index 3a332a5b5..fcd9d7209 100644
--- a/Orm/Xtensive.Orm/Sql/Info/TemporaryTableInfo.cs
+++ b/Orm/Xtensive.Orm/Sql/Info/TemporaryTableInfo.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Core;
 
 namespace Xtensive.Sql.Info
diff --git a/Orm/Xtensive.Orm/Sql/Info/ValueRange.cs b/Orm/Xtensive.Orm/Sql/Info/ValueRange.cs
index 7e089a113..6f30a086e 100644
--- a/Orm/Xtensive.Orm/Sql/Info/ValueRange.cs
+++ b/Orm/Xtensive.Orm/Sql/Info/ValueRange.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.07.07
 
-using System;
 using System.Diagnostics;
 
 namespace Xtensive.Sql.Info
diff --git a/Orm/Xtensive.Orm/Sql/Info/ValueRange{T}.cs b/Orm/Xtensive.Orm/Sql/Info/ValueRange{T}.cs
index ee75aac27..82f7b100b 100644
--- a/Orm/Xtensive.Orm/Sql/Info/ValueRange{T}.cs
+++ b/Orm/Xtensive.Orm/Sql/Info/ValueRange{T}.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 
 
 namespace Xtensive.Sql.Info
diff --git a/Orm/Xtensive.Orm/Sql/Info/ViewFeatures.cs b/Orm/Xtensive.Orm/Sql/Info/ViewFeatures.cs
index 37426b22b..4f3b89f1b 100644
--- a/Orm/Xtensive.Orm/Sql/Info/ViewFeatures.cs
+++ b/Orm/Xtensive.Orm/Sql/Info/ViewFeatures.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 
 namespace Xtensive.Sql.Info
 {
diff --git a/Orm/Xtensive.Orm/Sql/Interfaces/ILargeObject.cs b/Orm/Xtensive.Orm/Sql/Interfaces/ILargeObject.cs
index 42158cc1c..dc1ea5903 100644
--- a/Orm/Xtensive.Orm/Sql/Interfaces/ILargeObject.cs
+++ b/Orm/Xtensive.Orm/Sql/Interfaces/ILargeObject.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.08.11
 
-using System;
 using System.Data.Common;
 
 namespace Xtensive.Sql
diff --git a/Orm/Xtensive.Orm/Sql/Interfaces/ISqlNode.cs b/Orm/Xtensive.Orm/Sql/Interfaces/ISqlNode.cs
index cbdeb2e6e..a80313bd9 100644
--- a/Orm/Xtensive.Orm/Sql/Interfaces/ISqlNode.cs
+++ b/Orm/Xtensive.Orm/Sql/Interfaces/ISqlNode.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 
 namespace Xtensive.Sql
 {
diff --git a/Orm/Xtensive.Orm/Sql/Interfaces/ISqlQueryExpression.cs b/Orm/Xtensive.Orm/Sql/Interfaces/ISqlQueryExpression.cs
index 8f2306640..6c2a86679 100644
--- a/Orm/Xtensive.Orm/Sql/Interfaces/ISqlQueryExpression.cs
+++ b/Orm/Xtensive.Orm/Sql/Interfaces/ISqlQueryExpression.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System.Collections.Generic;
 using Xtensive.Sql.Dml;
 
 namespace Xtensive.Sql
diff --git a/Orm/Xtensive.Orm/Sql/Internals/SqlNodeCloneContext.cs b/Orm/Xtensive.Orm/Sql/Internals/SqlNodeCloneContext.cs
index a67f025d1..2c48205f8 100644
--- a/Orm/Xtensive.Orm/Sql/Internals/SqlNodeCloneContext.cs
+++ b/Orm/Xtensive.Orm/Sql/Internals/SqlNodeCloneContext.cs
@@ -2,8 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Collections.Generic;
 
 namespace Xtensive.Sql
 {
diff --git a/Orm/Xtensive.Orm/Sql/Internals/SqlValidator.cs b/Orm/Xtensive.Orm/Sql/Internals/SqlValidator.cs
index a42e9cbad..321a18851 100644
--- a/Orm/Xtensive.Orm/Sql/Internals/SqlValidator.cs
+++ b/Orm/Xtensive.Orm/Sql/Internals/SqlValidator.cs
@@ -2,9 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Core;
 using Xtensive.Reflection;
 using Xtensive.Sql.Dml;
diff --git a/Orm/Xtensive.Orm/Sql/Model/Action.cs b/Orm/Xtensive.Orm/Sql/Model/Action.cs
index 95200cfa2..148f350cf 100644
--- a/Orm/Xtensive.Orm/Sql/Model/Action.cs
+++ b/Orm/Xtensive.Orm/Sql/Model/Action.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 
 namespace Xtensive.Sql
 {
diff --git a/Orm/Xtensive.Orm/Sql/Model/BoundaryType.cs b/Orm/Xtensive.Orm/Sql/Model/BoundaryType.cs
index 7b39da0ea..9f59ac665 100644
--- a/Orm/Xtensive.Orm/Sql/Model/BoundaryType.cs
+++ b/Orm/Xtensive.Orm/Sql/Model/BoundaryType.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 
 namespace Xtensive.Sql
 {
diff --git a/Orm/Xtensive.Orm/Sql/Model/Catalog.cs b/Orm/Xtensive.Orm/Sql/Model/Catalog.cs
index c3c66c4b8..23db71c7e 100644
--- a/Orm/Xtensive.Orm/Sql/Model/Catalog.cs
+++ b/Orm/Xtensive.Orm/Sql/Model/Catalog.cs
@@ -2,8 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Collections.Generic;
 using Xtensive.Core;
 
 namespace Xtensive.Sql.Model
diff --git a/Orm/Xtensive.Orm/Sql/Model/CatalogNode.cs b/Orm/Xtensive.Orm/Sql/Model/CatalogNode.cs
index e3e1e3ac8..1c6264bc4 100644
--- a/Orm/Xtensive.Orm/Sql/Model/CatalogNode.cs
+++ b/Orm/Xtensive.Orm/Sql/Model/CatalogNode.cs
@@ -2,8 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
-using System.Collections.Generic;
 using Xtensive.Core;
 
 namespace Xtensive.Sql.Model
diff --git a/Orm/Xtensive.Orm/Sql/Model/CharacterSet.cs b/Orm/Xtensive.Orm/Sql/Model/CharacterSet.cs
index f173e786d..ea15ce0d7 100644
--- a/Orm/Xtensive.Orm/Sql/Model/CharacterSet.cs
+++ b/Orm/Xtensive.Orm/Sql/Model/CharacterSet.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 
 namespace Xtensive.Sql.Model
 {
diff --git a/Orm/Xtensive.Orm/Sql/Model/CheckOptions.cs b/Orm/Xtensive.Orm/Sql/Model/CheckOptions.cs
index 4967498c5..26961b2fd 100644
--- a/Orm/Xtensive.Orm/Sql/Model/CheckOptions.cs
+++ b/Orm/Xtensive.Orm/Sql/Model/CheckOptions.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 
 namespace Xtensive.Sql
 {
diff --git a/Orm/Xtensive.Orm/Sql/Model/Collation.cs b/Orm/Xtensive.Orm/Sql/Model/Collation.cs
index 5038e2688..ca33542c4 100644
--- a/Orm/Xtensive.Orm/Sql/Model/Collation.cs
+++ b/Orm/Xtensive.Orm/Sql/Model/Collation.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 
 namespace Xtensive.Sql.Model
 {
diff --git a/Orm/Xtensive.Orm/Sql/Model/Constraints/Assertion.cs b/Orm/Xtensive.Orm/Sql/Model/Constraints/Assertion.cs
index 48f671316..78aeea471 100644
--- a/Orm/Xtensive.Orm/Sql/Model/Constraints/Assertion.cs
+++ b/Orm/Xtensive.Orm/Sql/Model/Constraints/Assertion.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Sql.Dml;
 
 namespace Xtensive.Sql.Model
diff --git a/Orm/Xtensive.Orm/Sql/Model/Constraints/CheckConstraint.cs b/Orm/Xtensive.Orm/Sql/Model/Constraints/CheckConstraint.cs
index 4731c3366..9c2e37351 100644
--- a/Orm/Xtensive.Orm/Sql/Model/Constraints/CheckConstraint.cs
+++ b/Orm/Xtensive.Orm/Sql/Model/Constraints/CheckConstraint.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Sql.Dml;
 
 namespace Xtensive.Sql.Model
diff --git a/Orm/Xtensive.Orm/Sql/Model/Constraints/Constraint.cs b/Orm/Xtensive.Orm/Sql/Model/Constraints/Constraint.cs
index 4723e2dca..fb965dcaa 100644
--- a/Orm/Xtensive.Orm/Sql/Model/Constraints/Constraint.cs
+++ b/Orm/Xtensive.Orm/Sql/Model/Constraints/Constraint.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Core;
 using Xtensive.Sql.Dml;
 
diff --git a/Orm/Xtensive.Orm/Sql/Model/Constraints/DefaultConstraint.cs b/Orm/Xtensive.Orm/Sql/Model/Constraints/DefaultConstraint.cs
index d866545bc..9cbe03c7c 100644
--- a/Orm/Xtensive.Orm/Sql/Model/Constraints/DefaultConstraint.cs
+++ b/Orm/Xtensive.Orm/Sql/Model/Constraints/DefaultConstraint.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.06.07
 
-using System;
 using Xtensive.Core;
 
 namespace Xtensive.Sql.Model
diff --git a/Orm/Xtensive.Orm/Sql/Model/Constraints/DomainConstraint.cs b/Orm/Xtensive.Orm/Sql/Model/Constraints/DomainConstraint.cs
index ab2502749..952e22f9a 100644
--- a/Orm/Xtensive.Orm/Sql/Model/Constraints/DomainConstraint.cs
+++ b/Orm/Xtensive.Orm/Sql/Model/Constraints/DomainConstraint.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Sql.Dml;
 
 namespace Xtensive.Sql.Model
diff --git a/Orm/Xtensive.Orm/Sql/Model/Constraints/ForeignKey.cs b/Orm/Xtensive.Orm/Sql/Model/Constraints/ForeignKey.cs
index a411e1bbc..81cd97842 100644
--- a/Orm/Xtensive.Orm/Sql/Model/Constraints/ForeignKey.cs
+++ b/Orm/Xtensive.Orm/Sql/Model/Constraints/ForeignKey.cs
@@ -2,8 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
-using System.Collections.Generic;
 using Xtensive.Collections;
 using Xtensive.Sql.Dml;
 
diff --git a/Orm/Xtensive.Orm/Sql/Model/Constraints/PrimaryKey.cs b/Orm/Xtensive.Orm/Sql/Model/Constraints/PrimaryKey.cs
index 9ca9d85ef..362a80ca1 100644
--- a/Orm/Xtensive.Orm/Sql/Model/Constraints/PrimaryKey.cs
+++ b/Orm/Xtensive.Orm/Sql/Model/Constraints/PrimaryKey.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 
 namespace Xtensive.Sql.Model
 {
diff --git a/Orm/Xtensive.Orm/Sql/Model/Constraints/TableConstraint.cs b/Orm/Xtensive.Orm/Sql/Model/Constraints/TableConstraint.cs
index 5b1051419..b87a57033 100644
--- a/Orm/Xtensive.Orm/Sql/Model/Constraints/TableConstraint.cs
+++ b/Orm/Xtensive.Orm/Sql/Model/Constraints/TableConstraint.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Sql.Dml;
 
 namespace Xtensive.Sql.Model
diff --git a/Orm/Xtensive.Orm/Sql/Model/Constraints/UniqueConstraint.cs b/Orm/Xtensive.Orm/Sql/Model/Constraints/UniqueConstraint.cs
index bbaabde17..98c4dbb3b 100644
--- a/Orm/Xtensive.Orm/Sql/Model/Constraints/UniqueConstraint.cs
+++ b/Orm/Xtensive.Orm/Sql/Model/Constraints/UniqueConstraint.cs
@@ -2,8 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
-using System.Collections.Generic;
 using Xtensive.Core;
 using Xtensive.Collections;
 
diff --git a/Orm/Xtensive.Orm/Sql/Model/DataTable.cs b/Orm/Xtensive.Orm/Sql/Model/DataTable.cs
index dd1826e8d..170ec7c25 100644
--- a/Orm/Xtensive.Orm/Sql/Model/DataTable.cs
+++ b/Orm/Xtensive.Orm/Sql/Model/DataTable.cs
@@ -2,8 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
-using System.Collections.Generic;
 
 namespace Xtensive.Sql.Model
 {
diff --git a/Orm/Xtensive.Orm/Sql/Model/DataTableColumn.cs b/Orm/Xtensive.Orm/Sql/Model/DataTableColumn.cs
index bebaf0482..94705c077 100644
--- a/Orm/Xtensive.Orm/Sql/Model/DataTableColumn.cs
+++ b/Orm/Xtensive.Orm/Sql/Model/DataTableColumn.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 
 namespace Xtensive.Sql.Model
 {
diff --git a/Orm/Xtensive.Orm/Sql/Model/DataTableNode.cs b/Orm/Xtensive.Orm/Sql/Model/DataTableNode.cs
index f2989807f..d91ce1019 100644
--- a/Orm/Xtensive.Orm/Sql/Model/DataTableNode.cs
+++ b/Orm/Xtensive.Orm/Sql/Model/DataTableNode.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Core;
 
 namespace Xtensive.Sql.Model
diff --git a/Orm/Xtensive.Orm/Sql/Model/Domain.cs b/Orm/Xtensive.Orm/Sql/Model/Domain.cs
index 660cf1f1d..7a372e472 100644
--- a/Orm/Xtensive.Orm/Sql/Model/Domain.cs
+++ b/Orm/Xtensive.Orm/Sql/Model/Domain.cs
@@ -2,8 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
-using System.Collections.Generic;
 using Xtensive.Core;
 using Xtensive.Sql.Dml;
 
diff --git a/Orm/Xtensive.Orm/Sql/Model/Extractor.cs b/Orm/Xtensive.Orm/Sql/Model/Extractor.cs
index ecf1b961a..ca1adbb5f 100644
--- a/Orm/Xtensive.Orm/Sql/Model/Extractor.cs
+++ b/Orm/Xtensive.Orm/Sql/Model/Extractor.cs
@@ -3,8 +3,6 @@
 // See the License.txt file in the project root for more information.
 
 using System.Data.Common;
-using System.Threading;
-using System.Threading.Tasks;
 
 namespace Xtensive.Sql.Model
 {
diff --git a/Orm/Xtensive.Orm/Sql/Model/FullTextIndex.cs b/Orm/Xtensive.Orm/Sql/Model/FullTextIndex.cs
index 4cc843da5..0f800c424 100644
--- a/Orm/Xtensive.Orm/Sql/Model/FullTextIndex.cs
+++ b/Orm/Xtensive.Orm/Sql/Model/FullTextIndex.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2010.01.14
 
-using System;
 using Xtensive.Core;
 
 namespace Xtensive.Sql.Model
diff --git a/Orm/Xtensive.Orm/Sql/Model/Index.cs b/Orm/Xtensive.Orm/Sql/Model/Index.cs
index 8731bc024..34efc7825 100644
--- a/Orm/Xtensive.Orm/Sql/Model/Index.cs
+++ b/Orm/Xtensive.Orm/Sql/Model/Index.cs
@@ -2,7 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
 using Xtensive.Core;
 using Xtensive.Sql.Dml;
 
diff --git a/Orm/Xtensive.Orm/Sql/Model/IndexColumn.cs b/Orm/Xtensive.Orm/Sql/Model/IndexColumn.cs
index 28ae805d1..26f526ddd 100644
--- a/Orm/Xtensive.Orm/Sql/Model/IndexColumn.cs
+++ b/Orm/Xtensive.Orm/Sql/Model/IndexColumn.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Core;
 using Xtensive.Sql.Dml;
 
diff --git a/Orm/Xtensive.Orm/Sql/Model/Interfaces/IConstrainable.cs b/Orm/Xtensive.Orm/Sql/Model/Interfaces/IConstrainable.cs
index 273004ec8..6d2adeb13 100644
--- a/Orm/Xtensive.Orm/Sql/Model/Interfaces/IConstrainable.cs
+++ b/Orm/Xtensive.Orm/Sql/Model/Interfaces/IConstrainable.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System.Collections.Generic;
 
 namespace Xtensive.Sql.Model
 {
diff --git a/Orm/Xtensive.Orm/Sql/Model/Interfaces/IPermission.cs b/Orm/Xtensive.Orm/Sql/Model/Interfaces/IPermission.cs
index fd2bdce55..4d98247d6 100644
--- a/Orm/Xtensive.Orm/Sql/Model/Interfaces/IPermission.cs
+++ b/Orm/Xtensive.Orm/Sql/Model/Interfaces/IPermission.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System.Collections.Generic;
 
 namespace Xtensive.Sql.Model
 {
diff --git a/Orm/Xtensive.Orm/Sql/Model/Language.cs b/Orm/Xtensive.Orm/Sql/Model/Language.cs
index 2c6ec0ae4..b1088d2c8 100644
--- a/Orm/Xtensive.Orm/Sql/Model/Language.cs
+++ b/Orm/Xtensive.Orm/Sql/Model/Language.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Gamzov
 // Created:    2010.01.25
 
-using System;
 
 namespace Xtensive.Sql.Model
 {
diff --git a/Orm/Xtensive.Orm/Sql/Model/Node.cs b/Orm/Xtensive.Orm/Sql/Model/Node.cs
index 07927af31..b3ae24316 100644
--- a/Orm/Xtensive.Orm/Sql/Model/Node.cs
+++ b/Orm/Xtensive.Orm/Sql/Model/Node.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using System.Diagnostics;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Sql/Model/NodeCollection.cs b/Orm/Xtensive.Orm/Sql/Model/NodeCollection.cs
index bd594c18f..8816f4944 100644
--- a/Orm/Xtensive.Orm/Sql/Model/NodeCollection.cs
+++ b/Orm/Xtensive.Orm/Sql/Model/NodeCollection.cs
@@ -2,8 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
-using System.Collections.Generic;
 using System.Diagnostics;
 using Xtensive.Collections;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Sql/Model/PairedNodeCollection.cs b/Orm/Xtensive.Orm/Sql/Model/PairedNodeCollection.cs
index 80dd0fa13..c3beacd99 100644
--- a/Orm/Xtensive.Orm/Sql/Model/PairedNodeCollection.cs
+++ b/Orm/Xtensive.Orm/Sql/Model/PairedNodeCollection.cs
@@ -2,9 +2,7 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
 using Xtensive.Core;
 
 namespace Xtensive.Sql.Model
diff --git a/Orm/Xtensive.Orm/Sql/Model/PartitionMethod.cs b/Orm/Xtensive.Orm/Sql/Model/PartitionMethod.cs
index 0d4a51e2b..7c2ca7c79 100644
--- a/Orm/Xtensive.Orm/Sql/Model/PartitionMethod.cs
+++ b/Orm/Xtensive.Orm/Sql/Model/PartitionMethod.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 
 namespace Xtensive.Sql.Model
 {
diff --git a/Orm/Xtensive.Orm/Sql/Model/Partitioning/HashPartition.cs b/Orm/Xtensive.Orm/Sql/Model/Partitioning/HashPartition.cs
index 5858acf70..c37944d37 100644
--- a/Orm/Xtensive.Orm/Sql/Model/Partitioning/HashPartition.cs
+++ b/Orm/Xtensive.Orm/Sql/Model/Partitioning/HashPartition.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 
 namespace Xtensive.Sql.Model
 {
diff --git a/Orm/Xtensive.Orm/Sql/Model/Partitioning/ListPartition.cs b/Orm/Xtensive.Orm/Sql/Model/Partitioning/ListPartition.cs
index 88722254b..6bb5a30e8 100644
--- a/Orm/Xtensive.Orm/Sql/Model/Partitioning/ListPartition.cs
+++ b/Orm/Xtensive.Orm/Sql/Model/Partitioning/ListPartition.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 
 namespace Xtensive.Sql.Model
 {
diff --git a/Orm/Xtensive.Orm/Sql/Model/Partitioning/Partition.cs b/Orm/Xtensive.Orm/Sql/Model/Partitioning/Partition.cs
index 739775ea4..1971e4e0e 100644
--- a/Orm/Xtensive.Orm/Sql/Model/Partitioning/Partition.cs
+++ b/Orm/Xtensive.Orm/Sql/Model/Partitioning/Partition.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Core;
 
 namespace Xtensive.Sql.Model
diff --git a/Orm/Xtensive.Orm/Sql/Model/Partitioning/PartitionDescriptor.cs b/Orm/Xtensive.Orm/Sql/Model/Partitioning/PartitionDescriptor.cs
index d26a9ebec..7fba60182 100644
--- a/Orm/Xtensive.Orm/Sql/Model/Partitioning/PartitionDescriptor.cs
+++ b/Orm/Xtensive.Orm/Sql/Model/Partitioning/PartitionDescriptor.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Core;
 
 namespace Xtensive.Sql.Model
diff --git a/Orm/Xtensive.Orm/Sql/Model/Partitioning/PartitionFunction.cs b/Orm/Xtensive.Orm/Sql/Model/Partitioning/PartitionFunction.cs
index 91a8be629..ddb3e7863 100644
--- a/Orm/Xtensive.Orm/Sql/Model/Partitioning/PartitionFunction.cs
+++ b/Orm/Xtensive.Orm/Sql/Model/Partitioning/PartitionFunction.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Core;
 
 namespace Xtensive.Sql.Model
diff --git a/Orm/Xtensive.Orm/Sql/Model/Partitioning/PartitionSchema.cs b/Orm/Xtensive.Orm/Sql/Model/Partitioning/PartitionSchema.cs
index f808c3106..6ddb83adc 100644
--- a/Orm/Xtensive.Orm/Sql/Model/Partitioning/PartitionSchema.cs
+++ b/Orm/Xtensive.Orm/Sql/Model/Partitioning/PartitionSchema.cs
@@ -2,8 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
-using System.Collections.Generic;
 using System.Collections.ObjectModel;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Sql/Model/Partitioning/RangePartition.cs b/Orm/Xtensive.Orm/Sql/Model/Partitioning/RangePartition.cs
index 8bf1bfcf7..f47fec79e 100644
--- a/Orm/Xtensive.Orm/Sql/Model/Partitioning/RangePartition.cs
+++ b/Orm/Xtensive.Orm/Sql/Model/Partitioning/RangePartition.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Core;
 
 namespace Xtensive.Sql.Model
diff --git a/Orm/Xtensive.Orm/Sql/Model/ReferentialAction.cs b/Orm/Xtensive.Orm/Sql/Model/ReferentialAction.cs
index 398012aa3..798ed3667 100644
--- a/Orm/Xtensive.Orm/Sql/Model/ReferentialAction.cs
+++ b/Orm/Xtensive.Orm/Sql/Model/ReferentialAction.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 
 namespace Xtensive.Sql
 {
diff --git a/Orm/Xtensive.Orm/Sql/Model/Schema.cs b/Orm/Xtensive.Orm/Sql/Model/Schema.cs
index da71e0a5f..8c81c324c 100644
--- a/Orm/Xtensive.Orm/Sql/Model/Schema.cs
+++ b/Orm/Xtensive.Orm/Sql/Model/Schema.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Core;
 using Xtensive.Sql.Dml;
 
diff --git a/Orm/Xtensive.Orm/Sql/Model/SchemaNode.cs b/Orm/Xtensive.Orm/Sql/Model/SchemaNode.cs
index 497d81cf6..839cb5e8d 100644
--- a/Orm/Xtensive.Orm/Sql/Model/SchemaNode.cs
+++ b/Orm/Xtensive.Orm/Sql/Model/SchemaNode.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Core;
 
 namespace Xtensive.Sql.Model
diff --git a/Orm/Xtensive.Orm/Sql/Model/Sequence.cs b/Orm/Xtensive.Orm/Sql/Model/Sequence.cs
index 3dcecaf34..52037f668 100644
--- a/Orm/Xtensive.Orm/Sql/Model/Sequence.cs
+++ b/Orm/Xtensive.Orm/Sql/Model/Sequence.cs
@@ -2,7 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
 using Xtensive.Core;
 
 namespace Xtensive.Sql.Model
diff --git a/Orm/Xtensive.Orm/Sql/Model/SequenceDescriptor.cs b/Orm/Xtensive.Orm/Sql/Model/SequenceDescriptor.cs
index 7817a6937..2cef2b93e 100644
--- a/Orm/Xtensive.Orm/Sql/Model/SequenceDescriptor.cs
+++ b/Orm/Xtensive.Orm/Sql/Model/SequenceDescriptor.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Core;
 
 namespace Xtensive.Sql.Model
diff --git a/Orm/Xtensive.Orm/Sql/Model/SpatialIndex.cs b/Orm/Xtensive.Orm/Sql/Model/SpatialIndex.cs
index 0ce8622e7..566467615 100644
--- a/Orm/Xtensive.Orm/Sql/Model/SpatialIndex.cs
+++ b/Orm/Xtensive.Orm/Sql/Model/SpatialIndex.cs
@@ -4,7 +4,6 @@
 // Created by: Dmitri Maximov
 // Created:    2011.09.25
 
-using System;
 
 namespace Xtensive.Sql.Model
 {
diff --git a/Orm/Xtensive.Orm/Sql/Model/SqlModelVisitor.cs b/Orm/Xtensive.Orm/Sql/Model/SqlModelVisitor.cs
index 9196ade65..a0d66887e 100644
--- a/Orm/Xtensive.Orm/Sql/Model/SqlModelVisitor.cs
+++ b/Orm/Xtensive.Orm/Sql/Model/SqlModelVisitor.cs
@@ -4,7 +4,6 @@
 // Created by: Ivan Galkin
 // Created:    2009.03.31
 
-using System;
 
 namespace Xtensive.Sql.Model
 {
diff --git a/Orm/Xtensive.Orm/Sql/Model/Table.cs b/Orm/Xtensive.Orm/Sql/Model/Table.cs
index e5b945526..fc2549f1b 100644
--- a/Orm/Xtensive.Orm/Sql/Model/Table.cs
+++ b/Orm/Xtensive.Orm/Sql/Model/Table.cs
@@ -2,8 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
-using System.Collections.Generic;
 using Xtensive.Collections;
 using Xtensive.Core;
 using Xtensive.Sql.Dml;
diff --git a/Orm/Xtensive.Orm/Sql/Model/TableColumn.cs b/Orm/Xtensive.Orm/Sql/Model/TableColumn.cs
index 1eb05cf3f..fa117c907 100644
--- a/Orm/Xtensive.Orm/Sql/Model/TableColumn.cs
+++ b/Orm/Xtensive.Orm/Sql/Model/TableColumn.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Core;
 using Xtensive.Sql.Dml;
 
diff --git a/Orm/Xtensive.Orm/Sql/Model/TemporaryTable.cs b/Orm/Xtensive.Orm/Sql/Model/TemporaryTable.cs
index 7e0b60172..2aee98abb 100644
--- a/Orm/Xtensive.Orm/Sql/Model/TemporaryTable.cs
+++ b/Orm/Xtensive.Orm/Sql/Model/TemporaryTable.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Core;
 
 namespace Xtensive.Sql.Model
diff --git a/Orm/Xtensive.Orm/Sql/Model/Translation.cs b/Orm/Xtensive.Orm/Sql/Model/Translation.cs
index d87f3adc5..4c22566c0 100644
--- a/Orm/Xtensive.Orm/Sql/Model/Translation.cs
+++ b/Orm/Xtensive.Orm/Sql/Model/Translation.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 
 namespace Xtensive.Sql.Model
 {
diff --git a/Orm/Xtensive.Orm/Sql/Model/View.cs b/Orm/Xtensive.Orm/Sql/Model/View.cs
index f8920b6d5..249d38e44 100644
--- a/Orm/Xtensive.Orm/Sql/Model/View.cs
+++ b/Orm/Xtensive.Orm/Sql/Model/View.cs
@@ -2,8 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
-using System.Collections.Generic;
 using Xtensive.Core;
 using Xtensive.Collections;
 using Xtensive.Sql.Dml;
diff --git a/Orm/Xtensive.Orm/Sql/Model/ViewColumn.cs b/Orm/Xtensive.Orm/Sql/Model/ViewColumn.cs
index 350ff69db..e7ee2e0d2 100644
--- a/Orm/Xtensive.Orm/Sql/Model/ViewColumn.cs
+++ b/Orm/Xtensive.Orm/Sql/Model/ViewColumn.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Core;
 
 namespace Xtensive.Sql.Model
diff --git a/Orm/Xtensive.Orm/Sql/SqlConnection.cs b/Orm/Xtensive.Orm/Sql/SqlConnection.cs
index b1f0c9b3b..b28300262 100644
--- a/Orm/Xtensive.Orm/Sql/SqlConnection.cs
+++ b/Orm/Xtensive.Orm/Sql/SqlConnection.cs
@@ -2,12 +2,9 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
 using System.Data;
 using System.Data.Common;
 using System.Runtime.CompilerServices;
-using System.Threading;
-using System.Threading.Tasks;
 using Xtensive.Collections;
 using Xtensive.Core;
 using Xtensive.Orm;
diff --git a/Orm/Xtensive.Orm/Sql/SqlDdl.cs b/Orm/Xtensive.Orm/Sql/SqlDdl.cs
index 2a0351f11..811eb7f38 100644
--- a/Orm/Xtensive.Orm/Sql/SqlDdl.cs
+++ b/Orm/Xtensive.Orm/Sql/SqlDdl.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.07.09
 
-using System;
 using Xtensive.Core;
 using Xtensive.Sql.Ddl;
 using Xtensive.Sql.Dml;
diff --git a/Orm/Xtensive.Orm/Sql/SqlDml.cs b/Orm/Xtensive.Orm/Sql/SqlDml.cs
index d6dd3cb75..e5af28c0b 100644
--- a/Orm/Xtensive.Orm/Sql/SqlDml.cs
+++ b/Orm/Xtensive.Orm/Sql/SqlDml.cs
@@ -2,8 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Collections.Generic;
 using System.Collections.ObjectModel;
 using System.Reflection;
 using Xtensive.Collections;
@@ -11,7 +9,6 @@
 using Xtensive.Reflection;
 using Xtensive.Sql.Dml;
 using Xtensive.Sql.Model;
-using System.Linq;
 
 namespace Xtensive.Sql
 {
diff --git a/Orm/Xtensive.Orm/Sql/SqlDriver.cs b/Orm/Xtensive.Orm/Sql/SqlDriver.cs
index 24dd3b175..ff21f3de4 100644
--- a/Orm/Xtensive.Orm/Sql/SqlDriver.cs
+++ b/Orm/Xtensive.Orm/Sql/SqlDriver.cs
@@ -2,11 +2,6 @@
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Threading;
-using System.Threading.Tasks;
 using Xtensive.Core;
 using Xtensive.Orm;
 using Xtensive.Reflection;
diff --git a/Orm/Xtensive.Orm/Sql/SqlDriverConfiguration.cs b/Orm/Xtensive.Orm/Sql/SqlDriverConfiguration.cs
index 7a7f0b5a9..1618556c0 100644
--- a/Orm/Xtensive.Orm/Sql/SqlDriverConfiguration.cs
+++ b/Orm/Xtensive.Orm/Sql/SqlDriverConfiguration.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.12.27
 
-using System;
-using System.Collections.Generic;
 using Xtensive.Core;
 using Xtensive.Orm;
 
diff --git a/Orm/Xtensive.Orm/Sql/SqlDriverFactory.cs b/Orm/Xtensive.Orm/Sql/SqlDriverFactory.cs
index 14fd6c46f..49dd106cf 100644
--- a/Orm/Xtensive.Orm/Sql/SqlDriverFactory.cs
+++ b/Orm/Xtensive.Orm/Sql/SqlDriverFactory.cs
@@ -5,8 +5,6 @@
 // Created:    2009.06.23
 
 using System.Data.Common;
-using System.Threading;
-using System.Threading.Tasks;
 using Xtensive.Core;
 using Xtensive.Orm;
 using Xtensive.Sql.Info;
diff --git a/Orm/Xtensive.Orm/Sql/SqlExtensions.cs b/Orm/Xtensive.Orm/Sql/SqlExtensions.cs
index 0cdfb1d58..a2728ffc5 100644
--- a/Orm/Xtensive.Orm/Sql/SqlExtensions.cs
+++ b/Orm/Xtensive.Orm/Sql/SqlExtensions.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.07.30
 
-using System;
-using System.Collections.Generic;
 using Xtensive.Core;
 using Xtensive.Orm;
 using Xtensive.Sql.Dml;
diff --git a/Orm/Xtensive.Orm/Sql/SqlHelper.cs b/Orm/Xtensive.Orm/Sql/SqlHelper.cs
index c9e4a8151..c60ad5c19 100644
--- a/Orm/Xtensive.Orm/Sql/SqlHelper.cs
+++ b/Orm/Xtensive.Orm/Sql/SqlHelper.cs
@@ -4,13 +4,9 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.07.17
 
-using System;
-using System.Collections.Generic;
 using System.Data;
 using System.Data.Common;
 using System.Runtime.CompilerServices;
-using System.Threading;
-using System.Threading.Tasks;
 using Xtensive.Core;
 using Xtensive.Orm;
 using Xtensive.Sql.Dml;
diff --git a/Orm/Xtensive.Orm/Sql/SqlNode.cs b/Orm/Xtensive.Orm/Sql/SqlNode.cs
index 293f94fc9..b0669710c 100644
--- a/Orm/Xtensive.Orm/Sql/SqlNode.cs
+++ b/Orm/Xtensive.Orm/Sql/SqlNode.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 
 namespace Xtensive.Sql
 {
diff --git a/Orm/Xtensive.Orm/Sql/SqlNodeType.cs b/Orm/Xtensive.Orm/Sql/SqlNodeType.cs
index f066f9a8f..f578f7543 100644
--- a/Orm/Xtensive.Orm/Sql/SqlNodeType.cs
+++ b/Orm/Xtensive.Orm/Sql/SqlNodeType.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 
 namespace Xtensive.Sql
 {
diff --git a/Orm/Xtensive.Orm/Sql/SqlStatement.cs b/Orm/Xtensive.Orm/Sql/SqlStatement.cs
index 49a5f7d0d..c839c7a33 100644
--- a/Orm/Xtensive.Orm/Sql/SqlStatement.cs
+++ b/Orm/Xtensive.Orm/Sql/SqlStatement.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 
 namespace Xtensive.Sql
 {
diff --git a/Orm/Xtensive.Orm/Sql/SqlType.cs b/Orm/Xtensive.Orm/Sql/SqlType.cs
index 895a17a3b..a64727d7a 100644
--- a/Orm/Xtensive.Orm/Sql/SqlType.cs
+++ b/Orm/Xtensive.Orm/Sql/SqlType.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 
 namespace Xtensive.Sql
 {
diff --git a/Orm/Xtensive.Orm/Sql/SqlValueType.cs b/Orm/Xtensive.Orm/Sql/SqlValueType.cs
index 160871d4c..302e01f42 100644
--- a/Orm/Xtensive.Orm/Sql/SqlValueType.cs
+++ b/Orm/Xtensive.Orm/Sql/SqlValueType.cs
@@ -2,7 +2,6 @@
 // All rights reserved.
 // For conditions of distribution and use, see license.
 
-using System;
 using Xtensive.Core;
 
 
diff --git a/Orm/Xtensive.Orm/Sql/ValueTypeMapping/CustomTypeMapper.cs b/Orm/Xtensive.Orm/Sql/ValueTypeMapping/CustomTypeMapper.cs
index 30d8c0e8a..87f070902 100644
--- a/Orm/Xtensive.Orm/Sql/ValueTypeMapping/CustomTypeMapper.cs
+++ b/Orm/Xtensive.Orm/Sql/ValueTypeMapping/CustomTypeMapper.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.06.07
 
-using System;
 using System.Data.Common;
 
 namespace Xtensive.Sql
diff --git a/Orm/Xtensive.Orm/Sql/ValueTypeMapping/TypeMapper.cs b/Orm/Xtensive.Orm/Sql/ValueTypeMapping/TypeMapper.cs
index 6d217e58c..ad0affd1d 100644
--- a/Orm/Xtensive.Orm/Sql/ValueTypeMapping/TypeMapper.cs
+++ b/Orm/Xtensive.Orm/Sql/ValueTypeMapping/TypeMapper.cs
@@ -4,11 +4,9 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.06.19
 
-using System;
 using System.Data;
 using System.Data.Common;
 using System.IO;
-using System.Linq;
 using Xtensive.Sql.Info;
 
 namespace Xtensive.Sql
diff --git a/Orm/Xtensive.Orm/Sql/ValueTypeMapping/TypeMapping.cs b/Orm/Xtensive.Orm/Sql/ValueTypeMapping/TypeMapping.cs
index 61a94a133..18c65ab7d 100644
--- a/Orm/Xtensive.Orm/Sql/ValueTypeMapping/TypeMapping.cs
+++ b/Orm/Xtensive.Orm/Sql/ValueTypeMapping/TypeMapping.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.07.03
 
-using System;
 using System.Data.Common;
 
 namespace Xtensive.Sql
diff --git a/Orm/Xtensive.Orm/Sql/ValueTypeMapping/TypeMappingRegistry.cs b/Orm/Xtensive.Orm/Sql/ValueTypeMapping/TypeMappingRegistry.cs
index 2b08bc039..11d22bde0 100644
--- a/Orm/Xtensive.Orm/Sql/ValueTypeMapping/TypeMappingRegistry.cs
+++ b/Orm/Xtensive.Orm/Sql/ValueTypeMapping/TypeMappingRegistry.cs
@@ -4,10 +4,7 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.07.03
 
-using System;
-using System.Collections.Generic;
 using System.Collections.ObjectModel;
-using System.Linq;
 using Xtensive.Reflection;
 
 namespace Xtensive.Sql
diff --git a/Orm/Xtensive.Orm/Sql/ValueTypeMapping/TypeMappingRegistryBuilder.cs b/Orm/Xtensive.Orm/Sql/ValueTypeMapping/TypeMappingRegistryBuilder.cs
index 89e0fd794..03234bf94 100644
--- a/Orm/Xtensive.Orm/Sql/ValueTypeMapping/TypeMappingRegistryBuilder.cs
+++ b/Orm/Xtensive.Orm/Sql/ValueTypeMapping/TypeMappingRegistryBuilder.cs
@@ -4,10 +4,7 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.06.07
 
-using System;
-using System.Collections.Generic;
 using System.Data.Common;
-using System.Linq;
 using Xtensive.Core;
 
 namespace Xtensive.Sql
diff --git a/Orm/Xtensive.Orm/Sql/ValueTypeMapping/ValueRangeValidator.cs b/Orm/Xtensive.Orm/Sql/ValueTypeMapping/ValueRangeValidator.cs
index 75ec14773..6f48acec8 100644
--- a/Orm/Xtensive.Orm/Sql/ValueTypeMapping/ValueRangeValidator.cs
+++ b/Orm/Xtensive.Orm/Sql/ValueTypeMapping/ValueRangeValidator.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2009.12.03
 
-using System;
 using Xtensive.Reflection;
 using Xtensive.Sql.Info;
 
diff --git a/Orm/Xtensive.Orm/Strings.Designer.cs b/Orm/Xtensive.Orm/Strings.Designer.cs
index 284d869e3..12a79c401 100644
--- a/Orm/Xtensive.Orm/Strings.Designer.cs
+++ b/Orm/Xtensive.Orm/Strings.Designer.cs
@@ -9,7 +9,6 @@
 //------------------------------------------------------------------------------
 
 namespace Xtensive {
-    using System;
     
     
     /// <summary>
diff --git a/Orm/Xtensive.Orm/Tuples/DifferentialTuple.cs b/Orm/Xtensive.Orm/Tuples/DifferentialTuple.cs
index e221bd07f..34b8fcfe4 100644
--- a/Orm/Xtensive.Orm/Tuples/DifferentialTuple.cs
+++ b/Orm/Xtensive.Orm/Tuples/DifferentialTuple.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.05.22
 
-using System;
 using System.Diagnostics;
 using System.Runtime.Serialization;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Tuples/FastReadOnlyTuple.cs b/Orm/Xtensive.Orm/Tuples/FastReadOnlyTuple.cs
index 55c1f452a..6587e9874 100644
--- a/Orm/Xtensive.Orm/Tuples/FastReadOnlyTuple.cs
+++ b/Orm/Xtensive.Orm/Tuples/FastReadOnlyTuple.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.11.01
 
-using System;
 using System.Diagnostics;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Tuples/Interfaces/ITuple.cs b/Orm/Xtensive.Orm/Tuples/Interfaces/ITuple.cs
index 2def5c201..0197dc013 100644
--- a/Orm/Xtensive.Orm/Tuples/Interfaces/ITuple.cs
+++ b/Orm/Xtensive.Orm/Tuples/Interfaces/ITuple.cs
@@ -4,7 +4,6 @@
 // Created by: Nick Svetlov
 // Created:    2007.05.30
 
-using System;
 
 namespace Xtensive.Tuples
 {
diff --git a/Orm/Xtensive.Orm/Tuples/Packed/PackedFieldAccessor.cs b/Orm/Xtensive.Orm/Tuples/Packed/PackedFieldAccessor.cs
index abea03b20..fea9419be 100644
--- a/Orm/Xtensive.Orm/Tuples/Packed/PackedFieldAccessor.cs
+++ b/Orm/Xtensive.Orm/Tuples/Packed/PackedFieldAccessor.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2013.01.22
 
-using System;
 using System.Numerics;
 
 namespace Xtensive.Tuples.Packed
diff --git a/Orm/Xtensive.Orm/Tuples/Packed/PackedFieldDescriptor.cs b/Orm/Xtensive.Orm/Tuples/Packed/PackedFieldDescriptor.cs
index e97d0d27d..136b9bf2d 100644
--- a/Orm/Xtensive.Orm/Tuples/Packed/PackedFieldDescriptor.cs
+++ b/Orm/Xtensive.Orm/Tuples/Packed/PackedFieldDescriptor.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.12.29
 
-using System;
 
 namespace Xtensive.Tuples.Packed
 {
diff --git a/Orm/Xtensive.Orm/Tuples/Packed/PackedTuple.cs b/Orm/Xtensive.Orm/Tuples/Packed/PackedTuple.cs
index 22185d43d..864f7d05f 100644
--- a/Orm/Xtensive.Orm/Tuples/Packed/PackedTuple.cs
+++ b/Orm/Xtensive.Orm/Tuples/Packed/PackedTuple.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.12.29
 
-using System;
 
 namespace Xtensive.Tuples.Packed
 {
diff --git a/Orm/Xtensive.Orm/Tuples/Packed/PackingOrderInfoComparer.cs b/Orm/Xtensive.Orm/Tuples/Packed/PackingOrderInfoComparer.cs
index d283fa272..40072d59f 100644
--- a/Orm/Xtensive.Orm/Tuples/Packed/PackingOrderInfoComparer.cs
+++ b/Orm/Xtensive.Orm/Tuples/Packed/PackingOrderInfoComparer.cs
@@ -1,4 +1,3 @@
-using System.Collections.Generic;
 
 namespace Xtensive.Tuples.Packed
 {
diff --git a/Orm/Xtensive.Orm/Tuples/Packed/TupleLayout.cs b/Orm/Xtensive.Orm/Tuples/Packed/TupleLayout.cs
index 0eabb6326..a1e914d8d 100644
--- a/Orm/Xtensive.Orm/Tuples/Packed/TupleLayout.cs
+++ b/Orm/Xtensive.Orm/Tuples/Packed/TupleLayout.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2012.12.29
 
-using System;
 using System.Runtime.CompilerServices;
 using Xtensive.Reflection;
 
diff --git a/Orm/Xtensive.Orm/Tuples/ReferencedTuple.cs b/Orm/Xtensive.Orm/Tuples/ReferencedTuple.cs
index 087cbfb9d..85506a910 100644
--- a/Orm/Xtensive.Orm/Tuples/ReferencedTuple.cs
+++ b/Orm/Xtensive.Orm/Tuples/ReferencedTuple.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Kofman
 // Created:    2009.04.03
 
-using System;
 using Xtensive.Core;
 
 
diff --git a/Orm/Xtensive.Orm/Tuples/RegularTuple.cs b/Orm/Xtensive.Orm/Tuples/RegularTuple.cs
index 05147fdfa..e0d5c8d9a 100644
--- a/Orm/Xtensive.Orm/Tuples/RegularTuple.cs
+++ b/Orm/Xtensive.Orm/Tuples/RegularTuple.cs
@@ -4,7 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.01.24
 
-using System;
 using System.Runtime.Serialization;
 
 
diff --git a/Orm/Xtensive.Orm/Tuples/Transform/CombineTransform.cs b/Orm/Xtensive.Orm/Tuples/Transform/CombineTransform.cs
index 210fa33d2..f78ea4a76 100644
--- a/Orm/Xtensive.Orm/Tuples/Transform/CombineTransform.cs
+++ b/Orm/Xtensive.Orm/Tuples/Transform/CombineTransform.cs
@@ -4,10 +4,7 @@
 // Created by: Alexey Kochetov
 // Created:    2008.04.30
 
-using System;
-using System.Collections.Generic;
 using System.Diagnostics;
-using System.Linq;
 using Xtensive.Core;
 using Xtensive.Reflection;
 
diff --git a/Orm/Xtensive.Orm/Tuples/Transform/CutInTransform.cs b/Orm/Xtensive.Orm/Tuples/Transform/CutInTransform.cs
index 222374fe9..0996468d0 100644
--- a/Orm/Xtensive.Orm/Tuples/Transform/CutInTransform.cs
+++ b/Orm/Xtensive.Orm/Tuples/Transform/CutInTransform.cs
@@ -4,10 +4,7 @@
 // Created by: Elena Vakhtina
 // Created:    20.06.2008
 
-using System;
-using System.Collections.Generic;
 using System.Diagnostics;
-using System.Linq;
 using Xtensive.Core;
 using Xtensive.Reflection;
 
diff --git a/Orm/Xtensive.Orm/Tuples/Transform/CutInTransform{T}.cs b/Orm/Xtensive.Orm/Tuples/Transform/CutInTransform{T}.cs
index b8aaad88c..d063f6808 100644
--- a/Orm/Xtensive.Orm/Tuples/Transform/CutInTransform{T}.cs
+++ b/Orm/Xtensive.Orm/Tuples/Transform/CutInTransform{T}.cs
@@ -4,9 +4,6 @@
 // Created by: Elena Vakhtina
 // Created:    20.06.2008
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Xtensive.Collections;
 using Xtensive.Reflection;
 using Xtensive.Tuples.Transform;
diff --git a/Orm/Xtensive.Orm/Tuples/Transform/CutOutTransform.cs b/Orm/Xtensive.Orm/Tuples/Transform/CutOutTransform.cs
index 34dfd1247..7e0e5212c 100644
--- a/Orm/Xtensive.Orm/Tuples/Transform/CutOutTransform.cs
+++ b/Orm/Xtensive.Orm/Tuples/Transform/CutOutTransform.cs
@@ -4,7 +4,6 @@
 // Created by: Elena Vakhtina
 // Created:    2008.07.07
 
-using System;
 using System.Diagnostics;
 using Xtensive.Core;
 using Xtensive.Reflection;
diff --git a/Orm/Xtensive.Orm/Tuples/Transform/Internals/MapTransformTuple.cs b/Orm/Xtensive.Orm/Tuples/Transform/Internals/MapTransformTuple.cs
index 19628222c..e911e0c7f 100644
--- a/Orm/Xtensive.Orm/Tuples/Transform/Internals/MapTransformTuple.cs
+++ b/Orm/Xtensive.Orm/Tuples/Transform/Internals/MapTransformTuple.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Kochetov
 // Created:    2008.05.07
 
-using System;
-using System.Collections.Generic;
 using System.Diagnostics;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Tuples/Transform/Internals/MapTransformTuple1.cs b/Orm/Xtensive.Orm/Tuples/Transform/Internals/MapTransformTuple1.cs
index 7e2ca9dd2..26eac49ea 100644
--- a/Orm/Xtensive.Orm/Tuples/Transform/Internals/MapTransformTuple1.cs
+++ b/Orm/Xtensive.Orm/Tuples/Transform/Internals/MapTransformTuple1.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.06.04
 
-using System;
-using System.Collections.Generic;
 using Xtensive.Core;
 
 
diff --git a/Orm/Xtensive.Orm/Tuples/Transform/Internals/MapTransformTuple3.cs b/Orm/Xtensive.Orm/Tuples/Transform/Internals/MapTransformTuple3.cs
index fae607272..cb91e7a91 100644
--- a/Orm/Xtensive.Orm/Tuples/Transform/Internals/MapTransformTuple3.cs
+++ b/Orm/Xtensive.Orm/Tuples/Transform/Internals/MapTransformTuple3.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.06.04
 
-using System;
-using System.Collections.Generic;
 using Xtensive.Collections;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Tuples/Transform/Internals/ReadOnlyTransformTuple.cs b/Orm/Xtensive.Orm/Tuples/Transform/Internals/ReadOnlyTransformTuple.cs
index 3cca08abf..9442b6464 100644
--- a/Orm/Xtensive.Orm/Tuples/Transform/Internals/ReadOnlyTransformTuple.cs
+++ b/Orm/Xtensive.Orm/Tuples/Transform/Internals/ReadOnlyTransformTuple.cs
@@ -4,8 +4,6 @@
 // Created by: Nick Svetlov
 // Created:    2007.06.15
 
-using System;
-using System.Collections.Generic;
 using Xtensive.Collections;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Tuples/Transform/MapTransform.cs b/Orm/Xtensive.Orm/Tuples/Transform/MapTransform.cs
index 0bed3c1f9..bfedfe154 100644
--- a/Orm/Xtensive.Orm/Tuples/Transform/MapTransform.cs
+++ b/Orm/Xtensive.Orm/Tuples/Transform/MapTransform.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Kochetov
 // Created:    2008.05.07
 
-using System;
-using System.Collections.Generic;
 using System.Diagnostics;
 using Xtensive.Collections;
 using Xtensive.Core;
diff --git a/Orm/Xtensive.Orm/Tuples/Transform/ReadOnlyTransform.cs b/Orm/Xtensive.Orm/Tuples/Transform/ReadOnlyTransform.cs
index b235e8d8b..8a1160c31 100644
--- a/Orm/Xtensive.Orm/Tuples/Transform/ReadOnlyTransform.cs
+++ b/Orm/Xtensive.Orm/Tuples/Transform/ReadOnlyTransform.cs
@@ -4,9 +4,7 @@
 // Created by: Alex Yakunin
 // Created:    2008.06.02
 
-using System;
 using System.Diagnostics;
-using System.Linq;
 using Xtensive.Core;
 
 using Xtensive.Tuples.Transform.Internals;
diff --git a/Orm/Xtensive.Orm/Tuples/Transform/SegmentTransform.cs b/Orm/Xtensive.Orm/Tuples/Transform/SegmentTransform.cs
index 4f04b02d5..59af74df5 100644
--- a/Orm/Xtensive.Orm/Tuples/Transform/SegmentTransform.cs
+++ b/Orm/Xtensive.Orm/Tuples/Transform/SegmentTransform.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kochetov
 // Created:    2008.05.20
 
-using System;
 using System.Diagnostics;
 using Xtensive.Core;
 using Xtensive.Reflection;
diff --git a/Orm/Xtensive.Orm/Tuples/Transform/TransformedTuple.cs b/Orm/Xtensive.Orm/Tuples/Transform/TransformedTuple.cs
index 34a88c5e7..5283ad6dc 100644
--- a/Orm/Xtensive.Orm/Tuples/Transform/TransformedTuple.cs
+++ b/Orm/Xtensive.Orm/Tuples/Transform/TransformedTuple.cs
@@ -4,8 +4,6 @@
 // Created by: Alexey Kochetov
 // Created:    2008.05.07
 
-using System;
-using System.Collections.Generic;
 using System.Diagnostics;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Tuples/Transform/TransformedTuple{TTupleTransform}.cs b/Orm/Xtensive.Orm/Tuples/Transform/TransformedTuple{TTupleTransform}.cs
index 54b7567ab..6bf5d0f91 100644
--- a/Orm/Xtensive.Orm/Tuples/Transform/TransformedTuple{TTupleTransform}.cs
+++ b/Orm/Xtensive.Orm/Tuples/Transform/TransformedTuple{TTupleTransform}.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kochetov
 // Created:    2008.04.30
 
-using System;
 using System.Diagnostics;
 
 
diff --git a/Orm/Xtensive.Orm/Tuples/Transform/TupleTransformBase.cs b/Orm/Xtensive.Orm/Tuples/Transform/TupleTransformBase.cs
index 00e241916..d31de0aa7 100644
--- a/Orm/Xtensive.Orm/Tuples/Transform/TupleTransformBase.cs
+++ b/Orm/Xtensive.Orm/Tuples/Transform/TupleTransformBase.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kochetov
 // Created:    2008.04.30
 
-using System;
 using System.Diagnostics;
 using Xtensive.Reflection;
 
diff --git a/Orm/Xtensive.Orm/Tuples/Transform/TupleTransformType.cs b/Orm/Xtensive.Orm/Tuples/Transform/TupleTransformType.cs
index 2a10b5e8f..8994e1458 100644
--- a/Orm/Xtensive.Orm/Tuples/Transform/TupleTransformType.cs
+++ b/Orm/Xtensive.Orm/Tuples/Transform/TupleTransformType.cs
@@ -4,7 +4,6 @@
 // Created by: Alexey Kochetov
 // Created:    2008.05.06
 
-using System;
 
 namespace Xtensive.Tuples.Transform
 {
diff --git a/Orm/Xtensive.Orm/Tuples/Transform/WrappingTransformTupleBase.cs b/Orm/Xtensive.Orm/Tuples/Transform/WrappingTransformTupleBase.cs
index 5d2c9aba6..69873a662 100644
--- a/Orm/Xtensive.Orm/Tuples/Transform/WrappingTransformTupleBase.cs
+++ b/Orm/Xtensive.Orm/Tuples/Transform/WrappingTransformTupleBase.cs
@@ -4,8 +4,6 @@
 // Created by: Alex Yakunin
 // Created:    2008.06.02
 
-using System;
-using System.Collections.Generic;
 using System.Diagnostics;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Tuples/Tuple.cs b/Orm/Xtensive.Orm/Tuples/Tuple.cs
index a6ea9ecf7..bd6346adf 100644
--- a/Orm/Xtensive.Orm/Tuples/Tuple.cs
+++ b/Orm/Xtensive.Orm/Tuples/Tuple.cs
@@ -4,7 +4,6 @@
 // Created by: Nick Svetlov
 // Created:    2007.05.30
 
-using System;
 using System.Diagnostics;
 using System.Runtime.CompilerServices;
 using System.Runtime.Serialization;
diff --git a/Orm/Xtensive.Orm/Tuples/TupleDescriptor.cs b/Orm/Xtensive.Orm/Tuples/TupleDescriptor.cs
index e0bd7acd0..37429b669 100644
--- a/Orm/Xtensive.Orm/Tuples/TupleDescriptor.cs
+++ b/Orm/Xtensive.Orm/Tuples/TupleDescriptor.cs
@@ -5,9 +5,7 @@
 // Created:    2007.05.30
 
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
 using System.Diagnostics;
 using System.Runtime.Serialization;
 using System.Text;
diff --git a/Orm/Xtensive.Orm/Tuples/TupleExtensions.cs b/Orm/Xtensive.Orm/Tuples/TupleExtensions.cs
index b6e382dae..5b37aa1e3 100644
--- a/Orm/Xtensive.Orm/Tuples/TupleExtensions.cs
+++ b/Orm/Xtensive.Orm/Tuples/TupleExtensions.cs
@@ -4,9 +4,7 @@
 // Created by: Alex Yakunin
 // Created:    2008.05.31
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
 using Xtensive.Collections;
 using Xtensive.Core;
 
diff --git a/Orm/Xtensive.Orm/Tuples/TupleFieldState.cs b/Orm/Xtensive.Orm/Tuples/TupleFieldState.cs
index 2839d9ef4..c0ba26f11 100644
--- a/Orm/Xtensive.Orm/Tuples/TupleFieldState.cs
+++ b/Orm/Xtensive.Orm/Tuples/TupleFieldState.cs
@@ -4,7 +4,6 @@
 // Created by: Nick Svetlov
 // Created:    2007.06.18
 
-using System;
 
 namespace Xtensive.Tuples
 {
diff --git a/Orm/Xtensive.Orm/Tuples/TupleFieldStateExtensions.cs b/Orm/Xtensive.Orm/Tuples/TupleFieldStateExtensions.cs
index 43c5a3c1d..9be60805b 100644
--- a/Orm/Xtensive.Orm/Tuples/TupleFieldStateExtensions.cs
+++ b/Orm/Xtensive.Orm/Tuples/TupleFieldStateExtensions.cs
@@ -4,7 +4,6 @@
 // Created by: Alexis Kochetov
 // Created:    2009.09.17
 
-using System;
 using Xtensive.Tuples;
 
 using Tuple = Xtensive.Tuples.Tuple;
diff --git a/Orm/Xtensive.Orm/Tuples/TupleFormatExtensions.cs b/Orm/Xtensive.Orm/Tuples/TupleFormatExtensions.cs
index b131f5da5..8bdffd3da 100644
--- a/Orm/Xtensive.Orm/Tuples/TupleFormatExtensions.cs
+++ b/Orm/Xtensive.Orm/Tuples/TupleFormatExtensions.cs
@@ -4,8 +4,6 @@
 // Created by: Elena Vakhtina
 // Created:    2008.11.11
 
-using System;
-using System.Collections.Generic;
 using System.Text;
 using System.Text.RegularExpressions;
 using System.Web;
@@ -15,7 +13,6 @@
 using Xtensive.Tuples;
 using Xtensive.Reflection;
 using Tuple = Xtensive.Tuples.Tuple;
-using System.Linq;
 
 namespace Xtensive.Tuples
 {
diff --git a/Orm/Xtensive.Orm/Tuples/TupleUpdater.cs b/Orm/Xtensive.Orm/Tuples/TupleUpdater.cs
index 201a731c8..8a96f4d1c 100644
--- a/Orm/Xtensive.Orm/Tuples/TupleUpdater.cs
+++ b/Orm/Xtensive.Orm/Tuples/TupleUpdater.cs
@@ -4,7 +4,6 @@
 // Created by: Alexander Nikolaev
 // Created:    2009.03.17
 
-using System;
 using Xtensive.Core;
 
 
diff --git a/Weaver/Xtensive.Orm.Weaver/Application/ConsoleMessageWriter.cs b/Weaver/Xtensive.Orm.Weaver/Application/ConsoleMessageWriter.cs
index a75950489..ff90381c9 100644
--- a/Weaver/Xtensive.Orm.Weaver/Application/ConsoleMessageWriter.cs
+++ b/Weaver/Xtensive.Orm.Weaver/Application/ConsoleMessageWriter.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2013.08.19
 
-using System;
 
 namespace Xtensive.Orm.Weaver.Application
 {
diff --git a/Weaver/Xtensive.Orm.Weaver/Application/Program.cs b/Weaver/Xtensive.Orm.Weaver/Application/Program.cs
index 1132f0481..d4edd7dfd 100644
--- a/Weaver/Xtensive.Orm.Weaver/Application/Program.cs
+++ b/Weaver/Xtensive.Orm.Weaver/Application/Program.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2013.08.19
 
-using System;
 using System.IO;
 
 namespace Xtensive.Orm.Weaver.Application
diff --git a/Weaver/Xtensive.Orm.Weaver/AssemblyChecker.cs b/Weaver/Xtensive.Orm.Weaver/AssemblyChecker.cs
index e243e54ce..70cc56ab3 100644
--- a/Weaver/Xtensive.Orm.Weaver/AssemblyChecker.cs
+++ b/Weaver/Xtensive.Orm.Weaver/AssemblyChecker.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2013.09.02
 
-using System.Collections.Generic;
 using Mono.Cecil;
 
 namespace Xtensive.Orm.Weaver
diff --git a/Weaver/Xtensive.Orm.Weaver/AssemblyProcessor.cs b/Weaver/Xtensive.Orm.Weaver/AssemblyProcessor.cs
index 0e90415b4..eb27e7593 100644
--- a/Weaver/Xtensive.Orm.Weaver/AssemblyProcessor.cs
+++ b/Weaver/Xtensive.Orm.Weaver/AssemblyProcessor.cs
@@ -4,11 +4,8 @@
 // Created by: Denis Krjuchkov
 // Created:    2013.08.19
 
-using System;
-using System.Collections.Generic;
 using System.Diagnostics;
 using System.IO;
-using System.Linq;
 using Mono.Cecil;
 using Xtensive.Orm.Weaver.Stages;
 
diff --git a/Weaver/Xtensive.Orm.Weaver/AssemblyResolver.cs b/Weaver/Xtensive.Orm.Weaver/AssemblyResolver.cs
index e8fd454c6..84db08a83 100644
--- a/Weaver/Xtensive.Orm.Weaver/AssemblyResolver.cs
+++ b/Weaver/Xtensive.Orm.Weaver/AssemblyResolver.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2013.08.20
 
-using System;
-using System.Collections.Generic;
 using System.IO;
 using System.Reflection;
 using Mono.Cecil;
diff --git a/Weaver/Xtensive.Orm.Weaver/Extensions.cs b/Weaver/Xtensive.Orm.Weaver/Extensions.cs
index 78d2c8f3f..b79346520 100644
--- a/Weaver/Xtensive.Orm.Weaver/Extensions.cs
+++ b/Weaver/Xtensive.Orm.Weaver/Extensions.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2013.08.21
 
-using System.Collections.Generic;
-using System.Linq;
 using Mono.Cecil;
 using Mono.Collections.Generic;
 
diff --git a/Weaver/Xtensive.Orm.Weaver/FileHelper.cs b/Weaver/Xtensive.Orm.Weaver/FileHelper.cs
index f517f3006..1067092d8 100644
--- a/Weaver/Xtensive.Orm.Weaver/FileHelper.cs
+++ b/Weaver/Xtensive.Orm.Weaver/FileHelper.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2013.08.20
 
-using System;
 using System.IO;
 
 namespace Xtensive.Orm.Weaver
diff --git a/Weaver/Xtensive.Orm.Weaver/MessageLogger.cs b/Weaver/Xtensive.Orm.Weaver/MessageLogger.cs
index 324d75c65..664fd9359 100644
--- a/Weaver/Xtensive.Orm.Weaver/MessageLogger.cs
+++ b/Weaver/Xtensive.Orm.Weaver/MessageLogger.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2013.08.19
 
-using System;
-using System.Collections.Generic;
 using System.Globalization;
 
 namespace Xtensive.Orm.Weaver
diff --git a/Weaver/Xtensive.Orm.Weaver/ProcessorConfiguration.cs b/Weaver/Xtensive.Orm.Weaver/ProcessorConfiguration.cs
index b35d7a65e..e3f66cea7 100644
--- a/Weaver/Xtensive.Orm.Weaver/ProcessorConfiguration.cs
+++ b/Weaver/Xtensive.Orm.Weaver/ProcessorConfiguration.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2013.08.19
 
-using System;
-using System.Collections.Generic;
 
 namespace Xtensive.Orm.Weaver
 {
diff --git a/Weaver/Xtensive.Orm.Weaver/ProcessorContext.cs b/Weaver/Xtensive.Orm.Weaver/ProcessorContext.cs
index de29113c6..4d765aa67 100644
--- a/Weaver/Xtensive.Orm.Weaver/ProcessorContext.cs
+++ b/Weaver/Xtensive.Orm.Weaver/ProcessorContext.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2013.08.19
 
-using System;
-using System.Collections.Generic;
 using Mono.Cecil;
 
 namespace Xtensive.Orm.Weaver
diff --git a/Weaver/Xtensive.Orm.Weaver/ProcessorMessage.cs b/Weaver/Xtensive.Orm.Weaver/ProcessorMessage.cs
index ea8b82cb8..2ca14acda 100644
--- a/Weaver/Xtensive.Orm.Weaver/ProcessorMessage.cs
+++ b/Weaver/Xtensive.Orm.Weaver/ProcessorMessage.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2013.08.19
 
-using System;
 using System.Text;
 
 namespace Xtensive.Orm.Weaver
diff --git a/Weaver/Xtensive.Orm.Weaver/ProcessorStageAttribute.cs b/Weaver/Xtensive.Orm.Weaver/ProcessorStageAttribute.cs
index c0112b7a0..f8dab199e 100644
--- a/Weaver/Xtensive.Orm.Weaver/ProcessorStageAttribute.cs
+++ b/Weaver/Xtensive.Orm.Weaver/ProcessorStageAttribute.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2013.12.25
 
-using System;
 
 namespace Xtensive.Orm.Weaver
 {
diff --git a/Weaver/Xtensive.Orm.Weaver/PropertyInfo.cs b/Weaver/Xtensive.Orm.Weaver/PropertyInfo.cs
index 0571aa18b..9af23f40f 100644
--- a/Weaver/Xtensive.Orm.Weaver/PropertyInfo.cs
+++ b/Weaver/Xtensive.Orm.Weaver/PropertyInfo.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2013.08.26
 
-using System;
-using System.Collections.Generic;
 using System.Text;
 using Mono.Cecil;
 
diff --git a/Weaver/Xtensive.Orm.Weaver/ReferenceRegistry.cs b/Weaver/Xtensive.Orm.Weaver/ReferenceRegistry.cs
index a6d48a20b..d5a848aa6 100644
--- a/Weaver/Xtensive.Orm.Weaver/ReferenceRegistry.cs
+++ b/Weaver/Xtensive.Orm.Weaver/ReferenceRegistry.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2013.08.20
 
-using System.Collections.Generic;
 using Mono.Cecil;
 
 namespace Xtensive.Orm.Weaver
diff --git a/Weaver/Xtensive.Orm.Weaver/StageFailedException.cs b/Weaver/Xtensive.Orm.Weaver/StageFailedException.cs
index 3f778bf55..ec4ab65a0 100644
--- a/Weaver/Xtensive.Orm.Weaver/StageFailedException.cs
+++ b/Weaver/Xtensive.Orm.Weaver/StageFailedException.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2013.08.21
 
-using System;
 
 namespace Xtensive.Orm.Weaver
 {
diff --git a/Weaver/Xtensive.Orm.Weaver/Stages/FindPersistentTypesStage.cs b/Weaver/Xtensive.Orm.Weaver/Stages/FindPersistentTypesStage.cs
index 0d6e04d00..cf227bf9f 100644
--- a/Weaver/Xtensive.Orm.Weaver/Stages/FindPersistentTypesStage.cs
+++ b/Weaver/Xtensive.Orm.Weaver/Stages/FindPersistentTypesStage.cs
@@ -4,10 +4,7 @@
 // Created by: Denis Krjuchkov
 // Created:    2013.08.19
 
-using System;
-using System.Collections.Generic;
 using System.IO;
-using System.Linq;
 using Mono.Cecil;
 
 namespace Xtensive.Orm.Weaver.Stages
diff --git a/Weaver/Xtensive.Orm.Weaver/Stages/ImportReferencesStage.cs b/Weaver/Xtensive.Orm.Weaver/Stages/ImportReferencesStage.cs
index c2f7b1b61..118994504 100644
--- a/Weaver/Xtensive.Orm.Weaver/Stages/ImportReferencesStage.cs
+++ b/Weaver/Xtensive.Orm.Weaver/Stages/ImportReferencesStage.cs
@@ -4,9 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2013.08.20
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using Mono.Cecil;
 
 namespace Xtensive.Orm.Weaver.Stages
diff --git a/Weaver/Xtensive.Orm.Weaver/Stages/ModifyPersistentTypesStage.cs b/Weaver/Xtensive.Orm.Weaver/Stages/ModifyPersistentTypesStage.cs
index 5f8e0c016..50f14e862 100644
--- a/Weaver/Xtensive.Orm.Weaver/Stages/ModifyPersistentTypesStage.cs
+++ b/Weaver/Xtensive.Orm.Weaver/Stages/ModifyPersistentTypesStage.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2013.08.21
 
-using System.Linq;
 using Mono.Cecil;
 using Xtensive.Orm.Weaver.Tasks;
 
diff --git a/Weaver/Xtensive.Orm.Weaver/Tasks/AddAttributeTask.cs b/Weaver/Xtensive.Orm.Weaver/Tasks/AddAttributeTask.cs
index 284863120..b5c31b86c 100644
--- a/Weaver/Xtensive.Orm.Weaver/Tasks/AddAttributeTask.cs
+++ b/Weaver/Xtensive.Orm.Weaver/Tasks/AddAttributeTask.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2013.08.21
 
-using System;
 using Mono.Cecil;
 
 namespace Xtensive.Orm.Weaver.Tasks
diff --git a/Weaver/Xtensive.Orm.Weaver/Tasks/ImplementFactoryTask.cs b/Weaver/Xtensive.Orm.Weaver/Tasks/ImplementFactoryTask.cs
index 5ec71ea2f..1d9bad9e3 100644
--- a/Weaver/Xtensive.Orm.Weaver/Tasks/ImplementFactoryTask.cs
+++ b/Weaver/Xtensive.Orm.Weaver/Tasks/ImplementFactoryTask.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2013.08.19
 
-using System;
-using System.Linq;
 using Mono.Cecil;
 using Mono.Cecil.Cil;
 
diff --git a/Weaver/Xtensive.Orm.Weaver/Tasks/ImplementFieldAccessorTask.cs b/Weaver/Xtensive.Orm.Weaver/Tasks/ImplementFieldAccessorTask.cs
index 006a761d9..b712d675c 100644
--- a/Weaver/Xtensive.Orm.Weaver/Tasks/ImplementFieldAccessorTask.cs
+++ b/Weaver/Xtensive.Orm.Weaver/Tasks/ImplementFieldAccessorTask.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2013.08.19
 
-using System;
-using System.Collections.Generic;
 using Mono.Cecil;
 using Mono.Cecil.Cil;
 
diff --git a/Weaver/Xtensive.Orm.Weaver/Tasks/ImplementInitializablePatternTask.cs b/Weaver/Xtensive.Orm.Weaver/Tasks/ImplementInitializablePatternTask.cs
index 0c09c4399..cdb48908c 100644
--- a/Weaver/Xtensive.Orm.Weaver/Tasks/ImplementInitializablePatternTask.cs
+++ b/Weaver/Xtensive.Orm.Weaver/Tasks/ImplementInitializablePatternTask.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2013.08.19
 
-using System;
-using System.Linq;
 using Mono.Cecil;
 using Mono.Cecil.Cil;
 
diff --git a/Weaver/Xtensive.Orm.Weaver/Tasks/ImplementKeySetterTask.cs b/Weaver/Xtensive.Orm.Weaver/Tasks/ImplementKeySetterTask.cs
index ae343de3a..857135957 100644
--- a/Weaver/Xtensive.Orm.Weaver/Tasks/ImplementKeySetterTask.cs
+++ b/Weaver/Xtensive.Orm.Weaver/Tasks/ImplementKeySetterTask.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2013.08.19
 
-using System;
 using Mono.Cecil;
 using Mono.Cecil.Cil;
 
diff --git a/Weaver/Xtensive.Orm.Weaver/Tasks/RemoveBackingFieldTask.cs b/Weaver/Xtensive.Orm.Weaver/Tasks/RemoveBackingFieldTask.cs
index 19b8d9aff..6018effec 100644
--- a/Weaver/Xtensive.Orm.Weaver/Tasks/RemoveBackingFieldTask.cs
+++ b/Weaver/Xtensive.Orm.Weaver/Tasks/RemoveBackingFieldTask.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2013.08.21
 
-using System;
 using Mono.Cecil;
 using Mono.Cecil.Cil;
 
diff --git a/Weaver/Xtensive.Orm.Weaver/TypeIdentity.cs b/Weaver/Xtensive.Orm.Weaver/TypeIdentity.cs
index 4561fc97f..96927b9c9 100644
--- a/Weaver/Xtensive.Orm.Weaver/TypeIdentity.cs
+++ b/Weaver/Xtensive.Orm.Weaver/TypeIdentity.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2013.08.21
 
-using System;
 using Mono.Cecil;
 
 namespace Xtensive.Orm.Weaver
diff --git a/Weaver/Xtensive.Orm.Weaver/TypeInfo.cs b/Weaver/Xtensive.Orm.Weaver/TypeInfo.cs
index 1f427bef1..eb2967d81 100644
--- a/Weaver/Xtensive.Orm.Weaver/TypeInfo.cs
+++ b/Weaver/Xtensive.Orm.Weaver/TypeInfo.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2013.08.21
 
-using System;
-using System.Collections.Generic;
 using System.Text;
 using Mono.Cecil;
 
diff --git a/Weaver/Xtensive.Orm.Weaver/WeavingHelper.cs b/Weaver/Xtensive.Orm.Weaver/WeavingHelper.cs
index 1c241ac01..ea76103f4 100644
--- a/Weaver/Xtensive.Orm.Weaver/WeavingHelper.cs
+++ b/Weaver/Xtensive.Orm.Weaver/WeavingHelper.cs
@@ -4,8 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2013.08.20
 
-using System;
-using System.Collections.Generic;
 using System.Text;
 using Mono.Cecil;
 using Mono.Cecil.Cil;
diff --git a/Weaver/Xtensive.Orm.Weaver/WellKnown.cs b/Weaver/Xtensive.Orm.Weaver/WellKnown.cs
index a363ae729..c64fe12d7 100644
--- a/Weaver/Xtensive.Orm.Weaver/WellKnown.cs
+++ b/Weaver/Xtensive.Orm.Weaver/WellKnown.cs
@@ -4,7 +4,6 @@
 // Created by: Denis Krjuchkov
 // Created:    2013.08.20
 
-using System;
 using System.Collections.ObjectModel;
 
 namespace Xtensive.Orm.Weaver