Keep narrowed types after an unrolled foreach whose iterations all terminate

[janedbal]

Closes phpstan/phpstan#15390

A foreach over a constant array that returns for every value no longer narrows the subject after the loop. This is a regression in 2.3.0 from 003d601 (#6420).

foreach ([Status::A, Status::B, Status::C] as $s) {
	if ($status === $s) {
		return;
	}
}

\PHPStan\dumpType($status); // 2.2.17: *NEVER*, 2.3.0: Status

When every unrolled iteration terminates, the unrolled processing sets the chain scope to null. Without a break, the end scope stays null and ForeachHandler uses the scope of the generic final pass. That scope holds the subject with its full type.

• ForeachHandler now collects the end scope of each iteration that terminates. It merges these scopes into the end scope when the loop has no other exit.
• turbo-ext/src/ForeachHandler.cpp gets the same change.
• tests/PHPStan/Analyser/nsrt/bug-15390.php is the regression test. It fails without the change in ForeachHandler.php and passes with it.

— Claude

[phpstan-bot]

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