[phpstan-bot]

Summary

Take a foreach over a constant array where every iteration returns or throws, for example foreach ([Status::A, Status::B, Status::C] as $s) { if ($status === $s) return; }. Since 2.3.0, PHPStan no longer narrows the subject to never after such a loop. This PR restores the 2.2.x behaviour.

Changes

• src/Analyser/StmtHandler/ForeachHandler.php: tryProcessUnrolledConstantArrayForeach() now records the scope of each non-optional iteration that ends the unrolled chain because its body never reaches the next iteration. If no chain end scope and no break scope exist, it merges these scopes and uses them as the loop's end scope.
• turbo-ext/src/ForeachHandler.cpp: the same change in the native mirror. I checked that the regression test fails with the extension loaded and without the C++ change.

Root cause

Commit 003d601 ("Build a loop's back edge from its continue statements when the body end is unreachable") made the unrolled path set the chain scope to null once an iteration always terminates. With no break, the unrolled end scope then stayed null, and ForeachHandler used the generic final pass's scope instead. That pass binds the loop variable to the union of all values (Status::A|Status::B|Status::C), so $status was not narrowed. Before the commit, the unrolled path used the last iteration's end scope, where $status is never. The fix keeps that scope, but only as a fallback when the code after the loop is unreachable. It does not affect the possibly-undefined-variable fix from #14418, which still drops dead scopes whenever a real exit exists.

Analogous constructs I probed: while, for and do-while are never unrolled. The generic foreach path already falls back to the body result scope ($finalScope ??= $finalScopeResult->getScope()). The case where the terminating iteration ends in a bare return after continue already behaved the same way before the regression, because there the body's dead scope is not narrowed to never. So only the unrolled path needed the fix.

Test

tests/PHPStan/Analyser/nsrt/bug-15390.php covers:

• both snippets from the issue: an identity comparison against enum cases, and in_array() against nested constant arrays with a key variable
• an iteration that ends with throw and a constant integer union
• a control case where not every value is covered, so Status::C must remain after the loop

Fixes phpstan/phpstan#15390

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