diff --git a/Directory.Build.Props b/Directory.Build.Props
index 5f530da91..046271359 100644
--- a/Directory.Build.Props
+++ b/Directory.Build.Props
@@ -52,8 +52,9 @@
       <TreatWarningAsError>true</TreatWarningAsError>
       <SDLCheck>true</SDLCheck>
       <ConformanceMode>true</ConformanceMode>
-      <LanguageStandard Condition="'$(CppWinRTLanguageStandard)'==''">stdcpp17</LanguageStandard>
+      <LanguageStandard Condition="'$(CppWinRTLanguageStandard)'=='' Or '$(CppWinRTLanguageStandard)'=='17'">stdcpp17</LanguageStandard>
       <LanguageStandard Condition="'$(CppWinRTLanguageStandard)'=='20'">stdcpp20</LanguageStandard>
+      <LanguageStandard Condition="'$(CppWinRTLanguageStandard)'=='latest'">stdcpplatest</LanguageStandard>
       <PrecompiledHeader>Use</PrecompiledHeader>
       <PrecompiledHeaderFile>pch.h</PrecompiledHeaderFile>
       <PreprocessorDefinitions>CPPWINRT_VERSION_STRING="$(CppWinRTBuildVersion)";%(PreprocessorDefinitions)</PreprocessorDefinitions>
diff --git a/cppwinrt/code_writers.h b/cppwinrt/code_writers.h
index e24cfd302..60db08ad8 100644
--- a/cppwinrt/code_writers.h
+++ b/cppwinrt/code_writers.h
@@ -145,6 +145,28 @@ namespace cppwinrt
         }
     }
 
+    static void write_parent_imports(writer& w, cache const& c, std::string_view const& type_namespace)
+    {
+        auto pos = type_namespace.rfind('.');
+
+        if (pos == std::string::npos)
+        {
+            return;
+        }
+
+        auto parent = type_namespace.substr(0, pos);
+        auto found = c.namespaces().find(parent);
+
+        if (found != c.namespaces().end() && has_projected_types(found->second))
+        {
+            w.write_import(parent);
+        }
+        else
+        {
+            write_parent_imports(w, c, parent);
+        }
+    }
+
     static void write_pch(writer& w)
     {
         auto format = R"(#include "%"
@@ -313,11 +335,22 @@ namespace cppwinrt
             return;
         }
 
-        if (type_name == "Windows.Foundation.DateTime" ||
-            type_name == "Windows.Foundation.TimeSpan")
+        if (type_name.name_space == "Windows.Foundation")
         {
-            // Don't forward declare these since they're not structs.
-            return;
+            if (type_name.name == "DateTime" ||
+                type_name.name == "TimeSpan")
+            {
+                // Don't forward declare these since they're not structs.
+                return;
+            }
+
+            if (type_name.name == "Point" ||
+                type_name.name == "Rect" ||
+                type_name.name == "Size")
+            {
+                // Don't forward declare these since they're already defined in base.h.
+                return;
+            }
         }
 
         if (type_name.name_space == "Windows.Foundation.Numerics")
@@ -2812,7 +2845,12 @@ struct WINRT_IMPL_EMPTY_BASES produce_dispatch_to_overridable<T, D, %>
         }
     }
 
-    static bool write_structs(writer& w, std::vector<TypeDef> const& types)
+    struct write_structs_result
+    {
+        bool promote = false;
+    };
+
+    static write_structs_result write_structs(writer& w, std::vector<TypeDef> const& types)
     {
         auto format = R"(    struct %
     {
@@ -2829,7 +2867,7 @@ struct WINRT_IMPL_EMPTY_BASES produce_dispatch_to_overridable<T, D, %>
 
         if (types.empty())
         {
-            return false;
+            return {};
         }
 
         struct complex_struct
@@ -2895,7 +2933,7 @@ struct WINRT_IMPL_EMPTY_BASES produce_dispatch_to_overridable<T, D, %>
             }
         }
 
-        bool promote = false;
+        write_structs_result result;
         auto cpp_namespace = w.write_temp("@", w.type_namespace);
 
         for (auto&& type : structs)
@@ -2921,14 +2959,14 @@ struct WINRT_IMPL_EMPTY_BASES produce_dispatch_to_overridable<T, D, %>
                     continue;
                 }
 
-                if (!starts_with(field.second, cpp_namespace))
+                if (!result.promote && !starts_with(field.second, cpp_namespace))
                 {
-                    promote = true;
+                    result.promote = true;
                 }
             }
         }
 
-        return promote;
+        return result;
     }
 
     static void write_class_requires(writer& w, TypeDef const& type)
diff --git a/cppwinrt/cppwinrt.vcxproj b/cppwinrt/cppwinrt.vcxproj
index b8beed890..0825ea849 100644
--- a/cppwinrt/cppwinrt.vcxproj
+++ b/cppwinrt/cppwinrt.vcxproj
@@ -65,10 +65,12 @@
     <ClInclude Include="..\strings\base_macros.h" />
     <ClInclude Include="..\strings\base_marshaler.h" />
     <ClInclude Include="..\strings\base_meta.h" />
+    <ClInclude Include="..\strings\base_module.h" />
     <ClInclude Include="..\strings\base_natvis.h" />
     <ClInclude Include="..\strings\base_reference_produce.h" />
     <ClInclude Include="..\strings\base_reference_produce_1.h" />
     <ClInclude Include="..\strings\base_security.h" />
+    <ClInclude Include="..\strings\base_shared.h" />
     <ClInclude Include="..\strings\base_std_hash.h" />
     <ClInclude Include="..\strings\base_string.h" />
     <ClInclude Include="..\strings\base_stringable_format.h" />
diff --git a/cppwinrt/cppwinrt.vcxproj.filters b/cppwinrt/cppwinrt.vcxproj.filters
index 96129ab20..dfb12f27b 100644
--- a/cppwinrt/cppwinrt.vcxproj.filters
+++ b/cppwinrt/cppwinrt.vcxproj.filters
@@ -106,6 +106,9 @@
     <ClInclude Include="..\strings\base_meta.h">
       <Filter>strings</Filter>
     </ClInclude>
+    <ClInclude Include="..\strings\base_module.h">
+      <Filter>strings</Filter>
+    </ClInclude>
     <ClInclude Include="..\strings\base_natvis.h">
       <Filter>strings</Filter>
     </ClInclude>
@@ -187,6 +190,9 @@
     <ClInclude Include="..\strings\base_stringable_to_hstring.h">
       <Filter>strings</Filter>
     </ClInclude>
+    <ClInclude Include="..\strings\base_shared.h">
+      <Filter>strings</Filter>
+    </ClInclude>
   </ItemGroup>
   <ItemGroup>
     <ResourceCompile Include="$(OutDir)version.rc" />
diff --git a/cppwinrt/file_writers.h b/cppwinrt/file_writers.h
index ed9386b4e..50d2050dd 100644
--- a/cppwinrt/file_writers.h
+++ b/cppwinrt/file_writers.h
@@ -11,6 +11,7 @@ namespace cppwinrt
             auto wrap_file_guard = wrap_open_file_guard(w, "BASE");
 
             w.write(strings::base_includes);
+            w.write_root_include("shared");
             w.write(strings::base_macros);
             w.write(strings::base_types);
             w.write(strings::base_extern);
@@ -46,6 +47,26 @@ namespace cppwinrt
         w.flush_to_file(settings.output_folder + "winrt/base.h");
     }
 
+    static void write_shared_h()
+    {
+        writer w;
+        write_preamble(w);
+        w.write(strings::base_shared);
+        w.flush_to_file(settings.output_folder + "winrt/shared.h");
+    }
+
+    static void write_base_ixx()
+    {
+        writer ixx;
+        write_preamble(ixx);
+        ixx.write("module;\n");
+        ixx.write(strings::base_includes);
+        ixx.write_root_include("shared");
+        ixx.write(strings::base_module);
+        ixx.write_root_include("base");
+        ixx.flush_to_file(settings.output_folder + "winrt/ixx/base.ixx");
+    }
+
     static void write_fast_forward_h(std::vector<TypeDef> const& classes)
     {
         writer w;
@@ -65,6 +86,48 @@ namespace cppwinrt
         w.flush_to_file(settings.output_folder + "winrt/fast_forward.h");
     }
 
+    static void write_namespace_ixx(cache const& c, writer const& header_writer, std::string_view const& ns, char import_impl, char impl = 0)
+    {
+        writer w;
+        w.type_namespace = ns;
+        write_preamble(w);
+        w.write("module;\n");
+        w.write_root_include("shared");
+        w.write("#define WINRT_EXPORT export\n");
+        w.write("#define WINRT_IMPL_MODULES\n");
+        if (impl)
+        {
+            w.write("export module winrt:%.%;\n", ns, module_friendly_impl(impl));
+        }
+        else
+        {
+            w.write("export module winrt:%;\n", ns);
+        }
+
+        w.write("import std;\n");
+
+        w.write_import("base");
+        if (!impl)
+        {
+            write_parent_imports(w, c, ns);
+        }
+
+        for (auto&& depends : header_writer.depends)
+        {
+            w.write_import(depends.first, import_impl);
+        }
+
+        if (impl != '0')
+        {
+            w.write("export ");
+            w.write_import(ns, impl ? impl - 1 : '2');
+        }
+
+        w.write_depends(ns, impl);
+
+        w.save_module(impl);
+    }
+
     static void write_namespace_0_h(std::string_view const& ns, cache::namespace_members const& members)
     {
         writer w;
@@ -119,6 +182,8 @@ namespace cppwinrt
         }
 
         w.save_header('0');
+
+        write_namespace_ixx({}, {}, ns, 0, '0');
     }
 
     static void write_namespace_1_h(std::string_view const& ns, cache::namespace_members const& members)
@@ -137,13 +202,17 @@ namespace cppwinrt
         write_preamble(w);
         write_open_file_guard(w, ns, '1');
 
+        w.write("#ifndef WINRT_IMPL_MODULES\n");
         for (auto&& depends : w.depends)
         {
             w.write_depends(depends.first, '0');
         }
 
         w.write_depends(w.type_namespace, '0');
+        w.write("#endif\n");
         w.save_header('1');
+
+        write_namespace_ixx({}, w, ns, '0', '1');
     }
 
     static void write_namespace_2_h(std::string_view const& ns, cache::namespace_members const& members)
@@ -151,11 +220,11 @@ namespace cppwinrt
         writer w;
         w.type_namespace = ns;
 
-        bool promote;
+        write_structs_result structs_info;
         {
             auto wrap_type = wrap_type_namespace(w, ns);
             w.write_each<write_delegate>(members.delegates);
-            promote = write_structs(w, members.structs);
+            structs_info = write_structs(w, members.structs);
             w.write_each<write_class>(members.classes);
             w.write_each<write_interface_override>(members.classes);
         }
@@ -165,15 +234,19 @@ namespace cppwinrt
         write_preamble(w);
         write_open_file_guard(w, ns, '2');
 
-        char const impl = promote ? '2' : '1';
+        char const impl = structs_info.promote ? '2' : '1';
 
+        w.write("#ifndef WINRT_IMPL_MODULES\n");
         for (auto&& depends : w.depends)
         {
             w.write_depends(depends.first, impl);
         }
 
         w.write_depends(w.type_namespace, '1');
+        w.write("#endif\n");
         w.save_header('2');
+
+        write_namespace_ixx({}, w, ns, impl, '2');
     }
 
     static void write_namespace_h(cache const& c, std::string_view const& ns, cache::namespace_members const& members)
@@ -219,6 +292,7 @@ namespace cppwinrt
         w.swap();
         write_preamble(w);
         write_open_file_guard(w, ns);
+        w.write("#ifndef WINRT_IMPL_MODULES\n");
         write_version_assert(w);
         write_parent_depends(w, c, ns);
 
@@ -228,7 +302,10 @@ namespace cppwinrt
         }
 
         w.write_depends(w.type_namespace, '2');
+        w.write("#endif\n");
         w.save_header();
+
+        write_namespace_ixx(c, w, ns, '2');
     }
 
     static void write_module_g_cpp(std::vector<TypeDef> const& classes)
diff --git a/cppwinrt/main.cpp b/cppwinrt/main.cpp
index 70a55b076..1990e33f6 100644
--- a/cppwinrt/main.cpp
+++ b/cppwinrt/main.cpp
@@ -97,6 +97,7 @@ R"(  local               Local ^%WinDir^%\System32\WinMetadata folder
 
         path output_folder = args.value("output", ".");
         create_directories(output_folder / "winrt/impl");
+        create_directories(output_folder / "winrt/ixx");
         settings.output_folder = canonical(output_folder).string();
         settings.output_folder += std::filesystem::path::preferred_separator;
 
@@ -344,9 +345,9 @@ R"(  local               Local ^%WinDir^%\System32\WinMetadata folder
             group.synchronous(args.exists("synchronous"));
             writer ixx;
             write_preamble(ixx);
-            ixx.write("module;\n");
-            ixx.write(strings::base_includes);
-            ixx.write("\nexport module winrt;\n#define WINRT_EXPORT export\n\n");
+            ixx.write("export module winrt;\n");
+            ixx.write("export ");
+            ixx.write_import("base");
 
             for (auto&&[ns, members] : c.namespaces())
             {
@@ -355,7 +356,8 @@ R"(  local               Local ^%WinDir^%\System32\WinMetadata folder
                     continue;
                 }
 
-                ixx.write("#include \"winrt/%.h\"\n", ns);
+                ixx.write("export ");
+                ixx.write_import(ns);
 
                 group.add([&, &ns = ns, &members = members]
                 {
@@ -366,10 +368,14 @@ R"(  local               Local ^%WinDir^%\System32\WinMetadata folder
                 });
             }
 
+            ixx.flush_to_file(settings.output_folder + "winrt/ixx/winrt.ixx");
+
+            write_shared_h();
+
             if (settings.base)
             {
                 write_base_h();
-                ixx.flush_to_file(settings.output_folder + "winrt/winrt.ixx");
+                write_base_ixx();
             }
 
             if (settings.component)
diff --git a/cppwinrt/type_writers.h b/cppwinrt/type_writers.h
index 0fa3e5f8d..a80602222 100644
--- a/cppwinrt/type_writers.h
+++ b/cppwinrt/type_writers.h
@@ -104,6 +104,22 @@ namespace cppwinrt
         return false;
     }
 
+    std::string_view module_friendly_impl(char impl)
+    {
+        if (impl == '2')
+        {
+            return "two";
+        }
+        else if (impl == '1')
+        {
+            return "one";
+        }
+        else
+        {
+            return "zero";
+        }
+    }
+
     struct writer : writer_base<writer>
     {
         using writer_base<writer>::write;
@@ -576,6 +592,18 @@ namespace cppwinrt
             }
         }
 
+        void write_import(std::string_view const& ns, char impl = 0)
+        {
+            if (impl)
+            {
+                write("import :%.%;\n", ns, module_friendly_impl(impl));
+            }
+            else
+            {
+                write("import :%;\n", ns);
+            }
+        }
+
         void save_header(char impl = 0)
         {
             auto filename{ settings.output_folder + "winrt/" };
@@ -596,5 +624,21 @@ namespace cppwinrt
             filename += ".h";
             flush_to_file(filename);
         }
+
+        void save_module(char impl = 0)
+        {
+            auto filename{ settings.output_folder + "winrt/ixx/" };
+
+            filename += type_namespace;
+
+            if (impl)
+            {
+                filename += '.';
+                filename += module_friendly_impl(impl);
+            }
+
+            filename += ".ixx";
+            flush_to_file(filename);
+        }
     };
 }
diff --git a/natvis/pch.h b/natvis/pch.h
index 95e561971..090544429 100644
--- a/natvis/pch.h
+++ b/natvis/pch.h
@@ -11,6 +11,7 @@
 #include <vsdebugeng.templates.h>
 #include <Dia2.h>
 #include "base_includes.h"
+#include "base_shared.h"
 #include "base_macros.h"
 #include "base_types.h"
 #include "base_extern.h"
diff --git a/strings/base_macros.h b/strings/base_macros.h
index 3dc01fa2d..47b120fc2 100644
--- a/strings/base_macros.h
+++ b/strings/base_macros.h
@@ -1,20 +1,4 @@
 
-#ifdef _DEBUG
-
-#define WINRT_ASSERT _ASSERTE
-#define WINRT_VERIFY WINRT_ASSERT
-#define WINRT_VERIFY_(result, expression) WINRT_ASSERT(result == expression)
-
-#else
-
-#define WINRT_ASSERT(expression) ((void)0)
-#define WINRT_VERIFY(expression) (void)(expression)
-#define WINRT_VERIFY_(result, expression) (void)(expression)
-
-#endif
-
-#define WINRT_IMPL_SHIM(...) (*(abi_t<__VA_ARGS__>**)&static_cast<__VA_ARGS__ const&>(static_cast<D const&>(*this)))
-
 #ifdef _MSC_VER
 // Note: this is a workaround for a false-positive warning produced by the Visual C++ 15.9 compiler.
 #pragma warning(disable : 5046)
@@ -23,10 +7,6 @@
 #pragma warning(disable : 4268)
 #endif
 
-#if defined(__cpp_lib_coroutine)
-#define WINRT_IMPL_COROUTINES
-#endif
-
 #ifndef WINRT_EXPORT
 #define WINRT_EXPORT
 #endif
@@ -35,6 +15,8 @@
 #define _WINDOWS_NUMERICS_NAMESPACE_ winrt::Windows::Foundation::Numerics
 #define _WINDOWS_NUMERICS_BEGIN_NAMESPACE_ WINRT_EXPORT namespace winrt::Windows::Foundation::Numerics
 #define _WINDOWS_NUMERICS_END_NAMESPACE_
+// the include in purview of a module is intentional, we want to export the numeric types as part of the module
+#pragma warning(suppress: 5244)
 #include <windowsnumerics.impl.h>
 #undef _WINDOWS_NUMERICS_NAMESPACE_
 #undef _WINDOWS_NUMERICS_BEGIN_NAMESPACE_
@@ -49,30 +31,6 @@
 #define WINRT_IMPL_NOINLINE
 #endif
 
-#if defined(_MSC_VER)
-#define WINRT_IMPL_EMPTY_BASES __declspec(empty_bases)
-#else
-#define WINRT_IMPL_EMPTY_BASES
-#endif
-
-#if defined(_MSC_VER)
-#define WINRT_IMPL_NOVTABLE __declspec(novtable)
-#else
-#define WINRT_IMPL_NOVTABLE
-#endif
-
-#if defined(__clang__) && defined(__has_attribute)
-#if __has_attribute(__lto_visibility_public__)
-#define WINRT_IMPL_PUBLIC __attribute__((lto_visibility_public))
-#else
-#define WINRT_IMPL_PUBLIC
-#endif // __has_attribute(__lto_visibility_public__)
-#else
-#define WINRT_IMPL_PUBLIC
-#endif
-
-#define WINRT_IMPL_ABI_DECL WINRT_IMPL_NOVTABLE WINRT_IMPL_PUBLIC
-
 #if defined(__clang__)
 #define WINRT_IMPL_HAS_DECLSPEC_UUID __has_declspec_attribute(uuid)
 #elif defined(_MSC_VER)
diff --git a/strings/base_module.h b/strings/base_module.h
new file mode 100644
index 000000000..41216db01
--- /dev/null
+++ b/strings/base_module.h
@@ -0,0 +1,10 @@
+
+// Since modules don't result in global symbol pollution,
+// we can always enable the classic COM support.
+// Users will have to include headers declaring these interfaces
+// to make use of it.
+#include <Unknwn.h>
+
+#define WINRT_EXPORT export
+
+export module winrt:base;
diff --git a/strings/base_security.h b/strings/base_security.h
index 8160f11ad..3b3507f75 100644
--- a/strings/base_security.h
+++ b/strings/base_security.h
@@ -69,7 +69,7 @@ WINRT_EXPORT namespace winrt
             check_bool(WINRT_IMPL_SetThreadToken(nullptr, get()));
         }
 
-        auto operator()() const
+        /*TODO: figure out why compiler ICEs auto operator()() const
         {
             struct guard
             {
@@ -94,6 +94,6 @@ WINRT_EXPORT namespace winrt
             };
 
             return guard(impersonate());
-        }
+        }*/
     };
 }
diff --git a/strings/base_shared.h b/strings/base_shared.h
new file mode 100644
index 000000000..7e144c4a6
--- /dev/null
+++ b/strings/base_shared.h
@@ -0,0 +1,47 @@
+#include <version>
+
+#ifdef _DEBUG
+
+#include <crtdbg.h>
+
+#define WINRT_ASSERT _ASSERTE
+#define WINRT_VERIFY WINRT_ASSERT
+#define WINRT_VERIFY_(result, expression) WINRT_ASSERT(result == expression)
+
+#else
+
+#define WINRT_ASSERT(expression) ((void)0)
+#define WINRT_VERIFY(expression) (void)(expression)
+#define WINRT_VERIFY_(result, expression) (void)(expression)
+
+#endif
+
+#define WINRT_IMPL_SHIM(...) (*(abi_t<__VA_ARGS__>**)&static_cast<__VA_ARGS__ const&>(static_cast<D const&>(*this)))
+
+#if defined(__cpp_lib_coroutine)
+#define WINRT_IMPL_COROUTINES
+#endif
+
+#if defined(_MSC_VER)
+#define WINRT_IMPL_EMPTY_BASES __declspec(empty_bases)
+#else
+#define WINRT_IMPL_EMPTY_BASES
+#endif
+
+#if defined(_MSC_VER)
+#define WINRT_IMPL_NOVTABLE __declspec(novtable)
+#else
+#define WINRT_IMPL_NOVTABLE
+#endif
+
+#if defined(__clang__) && defined(__has_attribute)
+#if __has_attribute(__lto_visibility_public__)
+#define WINRT_IMPL_PUBLIC __attribute__((lto_visibility_public))
+#else
+#define WINRT_IMPL_PUBLIC
+#endif // __has_attribute(__lto_visibility_public__)
+#else
+#define WINRT_IMPL_PUBLIC
+#endif
+
+#define WINRT_IMPL_ABI_DECL WINRT_IMPL_NOVTABLE WINRT_IMPL_PUBLIC
diff --git a/strings/base_xaml_typename.h b/strings/base_xaml_typename.h
index 4a782fc72..215f27074 100644
--- a/strings/base_xaml_typename.h
+++ b/strings/base_xaml_typename.h
@@ -1,6 +1,8 @@
 
 namespace winrt::impl
 {
+    using namespace std::literals;
+
     template <typename T>
     struct xaml_typename_name
     {
diff --git a/test/test_cpp20/async.cpp b/test/test_cpp20/async.cpp
new file mode 100644
index 000000000..41b3e4cad
--- /dev/null
+++ b/test/test_cpp20/async.cpp
@@ -0,0 +1,92 @@
+#include <Windows.h>
+#include "catch.hpp"
+
+import std;
+import winrt;
+
+using namespace winrt;
+using namespace Windows::Foundation;
+using namespace std::chrono_literals;
+
+namespace
+{
+    //
+    // Just some quick tests to make sure that coroutines compile and work with C++20 modules.
+    // Taken from async_throw in test
+    //
+    // TODO: make a new project for this
+
+    IAsyncAction Action()
+    {
+        co_await 10ms;
+        throw hresult_invalid_argument(L"Async");
+    }
+
+    IAsyncActionWithProgress<int> ActionWithProgress()
+    {
+        co_await 10ms;
+        throw hresult_invalid_argument(L"Async");
+    }
+
+    IAsyncOperation<int> Operation()
+    {
+        co_await 10ms;
+        throw hresult_invalid_argument(L"Async");
+        co_return 1;
+    }
+
+    IAsyncOperationWithProgress<int, int> OperationWithProgress()
+    {
+        co_await 10ms;
+        throw hresult_invalid_argument(L"Async");
+        co_return 1;
+    }
+
+    template <typename F>
+    void Check(F make)
+    {
+        try
+        {
+            make().get();
+            REQUIRE(false);
+        }
+        catch (hresult_invalid_argument const& e)
+        {
+            REQUIRE(e.message() == L"Async");
+        }
+
+        handle completed{ CreateEvent(nullptr, true, false, nullptr) };
+        auto async = make();
+
+        async.Completed([&](auto&& sender, AsyncStatus status)
+            {
+                REQUIRE(async == sender);
+                REQUIRE(status == AsyncStatus::Error);
+                SetEvent(completed.get());
+            });
+
+        REQUIRE(WaitForSingleObject(completed.get(), 1000) == WAIT_OBJECT_0);
+        REQUIRE(async.Status() == AsyncStatus::Error);
+
+        hresult_error e(async.ErrorCode(), take_ownership_from_abi);
+        REQUIRE(e.message() == L"Async");
+
+        try
+        {
+            async.GetResults();
+            REQUIRE(false);
+        }
+        catch (hresult_invalid_argument const& e)
+        {
+            REQUIRE(e.message() == L"Async");
+        }
+    }
+}
+
+TEST_CASE("async_throw")
+{
+    Check(Action);
+    Check(ActionWithProgress);
+    Check(Operation);
+    Check(OperationWithProgress);
+}
diff --git a/test/test_cpp20/await_completed.cpp b/test/test_cpp20/await_completed.cpp
index 3ae64e25e..37c42e99f 100644
--- a/test/test_cpp20/await_completed.cpp
+++ b/test/test_cpp20/await_completed.cpp
@@ -1,4 +1,9 @@
-#include "pch.h"
+#include <coroutine>
+#include <intrin.h>
+
+#include "catch.hpp"
+
+import winrt;
 
 using namespace winrt;
 using namespace Windows::Foundation;
diff --git a/test/test_cpp20/format.cpp b/test/test_cpp20/format.cpp
index d16193328..977dad9b7 100644
--- a/test/test_cpp20/format.cpp
+++ b/test/test_cpp20/format.cpp
@@ -1,8 +1,10 @@
-#include "pch.h"
-
 #ifdef __cpp_lib_format
 #include <format>
 
+#include "catch.hpp"
+
+import winrt;
+
 struct stringable : winrt::implements<stringable, winrt::Windows::Foundation::IStringable>
 {
     winrt::hstring ToString()
diff --git a/test/test_cpp20/hstring.cpp b/test/test_cpp20/hstring.cpp
index 57d145fbb..a37c28959 100644
--- a/test/test_cpp20/hstring.cpp
+++ b/test/test_cpp20/hstring.cpp
@@ -1,4 +1,6 @@
-#include "pch.h"
+#include "catch.hpp"
+
+import winrt;
 
 TEST_CASE("hstring")
 {
diff --git a/test/test_cpp20/main.cpp b/test/test_cpp20/main.cpp
index 30687e00c..b3e937de6 100644
--- a/test/test_cpp20/main.cpp
+++ b/test/test_cpp20/main.cpp
@@ -5,7 +5,8 @@
 #define CATCH_CONFIG_WINDOWS_SEH
 
 #include "catch.hpp"
-#include "winrt/base.h"
+
+import winrt;
 
 using namespace winrt;
 
diff --git a/test/test_cpp20/pch.cpp b/test/test_cpp20/pch.cpp
deleted file mode 100644
index 1d9f38c57..000000000
--- a/test/test_cpp20/pch.cpp
+++ /dev/null
@@ -1 +0,0 @@
-#include "pch.h"
diff --git a/test/test_cpp20/pch.h b/test/test_cpp20/pch.h
deleted file mode 100644
index c1a8f5ff3..000000000
--- a/test/test_cpp20/pch.h
+++ /dev/null
@@ -1,17 +0,0 @@
-#pragma once
-
-#pragma warning(4: 4458) // ensure we compile clean with this warning enabled
-
-#define WINRT_LEAN_AND_MEAN
-#include <unknwn.h>
-#include "winrt/Windows.Data.Json.h"
-#include "winrt/Windows.Foundation.h"
-#include "winrt/Windows.Foundation.Collections.h"
-#include "winrt/Windows.Foundation.Numerics.h"
-#include "winrt/Windows.Storage.Streams.h"
-#include <winstring.h>
-#include "catch.hpp"
-
-#include <string_view>
-
-using namespace std::literals;
diff --git a/test/test_cpp20/ranges.cpp b/test/test_cpp20/ranges.cpp
index 9df542696..81b434c43 100644
--- a/test/test_cpp20/ranges.cpp
+++ b/test/test_cpp20/ranges.cpp
@@ -1,9 +1,11 @@
-#include "pch.h"
-
 #ifdef __cpp_lib_ranges
 #include <algorithm>
 #include <ranges>
 
+#include "catch.hpp"
+
+import winrt;
+
 TEST_CASE("ranges")
 {
     {
diff --git a/test/test_cpp20/test_cpp20.vcxproj b/test/test_cpp20/test_cpp20.vcxproj
index 4eaee0a18..4e90b64d1 100644
--- a/test/test_cpp20/test_cpp20.vcxproj
+++ b/test/test_cpp20/test_cpp20.vcxproj
@@ -93,6 +93,7 @@
       <AdditionalIncludeDirectories>$(OutputPath);Generated Files;..\</AdditionalIncludeDirectories>
       <PreprocessorDefinitions>NOMINMAX;_MBCS;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <RuntimeLibrary>MultiThreaded</RuntimeLibrary>
+      <PrecompiledHeader>NotUsing</PrecompiledHeader>
       <WarningLevel>Level4</WarningLevel>
       <TreatWarningAsError>true</TreatWarningAsError>
       <AdditionalOptions Condition="'$(Clang)'=='1'">%(AdditionalOptions) -O3 -flto -fwhole-program-vtables</AdditionalOptions>
@@ -117,6 +118,7 @@
       <AdditionalIncludeDirectories>$(OutputPath);Generated Files;..\</AdditionalIncludeDirectories>
       <PreprocessorDefinitions>NOMINMAX;_MBCS;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <RuntimeLibrary>MultiThreadedDebug</RuntimeLibrary>
+      <PrecompiledHeader>NotUsing</PrecompiledHeader>
       <WarningLevel>Level4</WarningLevel>
       <TreatWarningAsError>true</TreatWarningAsError>
       <AdditionalOptions Condition="'$(Clang)'=='1'">%(AdditionalOptions) -flto -fwhole-program-vtables</AdditionalOptions>
@@ -139,6 +141,7 @@
       <AdditionalIncludeDirectories>$(OutputPath);Generated Files;..\</AdditionalIncludeDirectories>
       <PreprocessorDefinitions>NOMINMAX;_MBCS;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <RuntimeLibrary>MultiThreadedDebug</RuntimeLibrary>
+      <PrecompiledHeader>NotUsing</PrecompiledHeader>
       <WarningLevel>Level4</WarningLevel>
       <TreatWarningAsError>true</TreatWarningAsError>
       <AdditionalOptions Condition="'$(Clang)'=='1'">%(AdditionalOptions) -flto -fwhole-program-vtables</AdditionalOptions>
@@ -161,6 +164,7 @@
       <AdditionalIncludeDirectories>$(OutputPath);Generated Files;..\</AdditionalIncludeDirectories>
       <PreprocessorDefinitions>NOMINMAX;_MBCS;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <RuntimeLibrary>MultiThreadedDebug</RuntimeLibrary>
+      <PrecompiledHeader>NotUsing</PrecompiledHeader>
       <WarningLevel>Level4</WarningLevel>
       <TreatWarningAsError>true</TreatWarningAsError>
       <AdditionalOptions Condition="'$(Clang)'=='1'">%(AdditionalOptions) -flto -fwhole-program-vtables</AdditionalOptions>
@@ -185,6 +189,7 @@
       <AdditionalIncludeDirectories>$(OutputPath);Generated Files;..\</AdditionalIncludeDirectories>
       <PreprocessorDefinitions>NOMINMAX;_MBCS;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <RuntimeLibrary>MultiThreaded</RuntimeLibrary>
+      <PrecompiledHeader>NotUsing</PrecompiledHeader>
       <WarningLevel>Level4</WarningLevel>
       <TreatWarningAsError>true</TreatWarningAsError>
       <AdditionalOptions Condition="'$(Clang)'=='1'">%(AdditionalOptions) -O3 -flto -fwhole-program-vtables</AdditionalOptions>
@@ -211,6 +216,7 @@
       <AdditionalIncludeDirectories>$(OutputPath);Generated Files;..\</AdditionalIncludeDirectories>
       <PreprocessorDefinitions>NOMINMAX;_MBCS;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <RuntimeLibrary>MultiThreaded</RuntimeLibrary>
+      <PrecompiledHeader>NotUsing</PrecompiledHeader>
       <WarningLevel>Level4</WarningLevel>
       <TreatWarningAsError>true</TreatWarningAsError>
       <AdditionalOptions Condition="'$(Clang)'=='1'">%(AdditionalOptions) -O3 -flto -fwhole-program-vtables</AdditionalOptions>
@@ -230,21 +236,15 @@
     </PostBuildEvent>
   </ItemDefinitionGroup>
   <ItemGroup>
-    <ClInclude Include="pch.h" />
-  </ItemGroup>
-  <ItemGroup>
+    <ClCompile Include="$(CppWinRTDir)winrt\ixx\*.ixx" />
+    <ClCompile Include="async.cpp" />
     <ClCompile Include="array_span.cpp" />
     <ClCompile Include="await_completed.cpp" />
     <ClCompile Include="clang_only.cpp" />
     <ClCompile Include="custom_error.cpp" />
     <ClCompile Include="format.cpp" />
     <ClCompile Include="hstring.cpp" />
-    <ClCompile Include="main.cpp">
-      <PrecompiledHeader>NotUsing</PrecompiledHeader>
-    </ClCompile>
-    <ClCompile Include="pch.cpp">
-      <PrecompiledHeader>Create</PrecompiledHeader>
-    </ClCompile>
+    <ClCompile Include="main.cpp" />
     <ClCompile Include="ranges.cpp" />
   </ItemGroup>
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />