Fix phpstan/phpstan#6189: Generator suspension points should be treated as infinite loop break points

[phpstan-bot]

Summary

PHPStan incorrectly reported "While loop condition is always true" for infinite loops inside generators that contain yield statements. A yield in a loop is effectively a suspension point — the generator pauses and can be abandoned by the caller, so the loop is not truly infinite. This is equivalent to InfiniteIterator in PHP's SPL.

Changes

• Added $hasYield parameter to src/Node/BreaklessWhileLoopNode.php constructor and a hasYield() getter
• Added $hasYield parameter to src/Node/DoWhileLoopConditionNode.php constructor and a hasYield() getter
• Updated src/Analyser/NodeScopeResolver.php to pass $finalScopeResult->hasYield() / $bodyScopeResult->hasYield() when constructing these nodes
• Updated src/Rules/Comparison/WhileLoopAlwaysTrueConditionRule.php to suppress the warning when the loop body contains a yield
• Updated src/Rules/Comparison/DoWhileLoopConstantConditionRule.php to suppress the always-true warning when the loop body contains a yield

Root cause

The WhileLoopAlwaysTrueConditionRule and DoWhileLoopConstantConditionRule had no awareness of yield statements inside the loop body. They only checked for break, continue, and return as exit points, plus the never return type on the enclosing function. Generator suspension via yield was not considered as a valid way to "exit" the loop iteration, leading to false positives.

Test

Added tests/PHPStan/Rules/Comparison/data/bug-6189.php with test cases covering:

• while(true) { yield 1; } — no warning (yield acts as suspension point)
• while(true) { yield from [...]; } — no warning (yield from also suspends)
• while(true) {} in a non-generator — still warns (truly infinite)
• yield outside the loop body with while(true) {} — still warns (yield doesn't help the loop)
• do { yield 1; } while(true); — no warning (do-while with yield)

Fixes phpstan/phpstan#6189
Fixes phpstan/phpstan#10054

[staabm]

also fixes phpstan/phpstan#10054

[staabm]

btw: I was not sure whether the yields should be within the exitPoints

[VincentLanglet]

I thought about it, but InternalStatementResult already differentiate $hasYield and $exitPoints so it seems consistent to me.