Compare conditional expressions in MutatingScope::equals() - #6344
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Compare conditional expressions in MutatingScope::equals()#6344janedbal wants to merge 2 commits into
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The loop handlers call equals() to detect an unchanged entry scope. Since 2.2.10 they skip the verification pass on an unchanged entry and replay the recorded pass instead of the final walk. Both shortcuts assume that equal scopes walk identically. But equals() ignored the conditional expressions, and those narrow types when a later condition is specified. A while loop nested in another loop shows the gap. The entry of the first pass still holds "if $toCurrent is int<1, max> then $items is non-empty-list" from the preceding if/else merge. The body invalidates it, so the second entry lacks it, but the expression types match and the second entry compares equal. The first pass is replayed, and array_shift($items) inside the loop is reported as never null. Co-Authored-By: Claude Code
Co-Authored-By: Claude Code
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Since 2.2.10 the loop handlers skip a verification pass when the entry scope is unchanged, and they replay the recorded pass instead of the final walk. Both shortcuts compare entry scopes with
MutatingScope::equals(), which ignored conditional expressions. Two scopes with equal expression types but different conditional expressions do not walk identically, because a later condition narrows through them.Reproducer: a
whilenested in another loop. The first pass enters withif $toCurrent is int<1, max> then $items is non-empty-listfrom the precedingif/elsemerge. The body invalidates it, so the second entry lacks it, but the two entries compare equal. The first pass is replayed, andarray_shift($items)inside the loop is reported as nevernull(identical.alwaysFalse).Bisected to 31a3604 ("Replay the recorded fixpoint pass instead of repeating the final loop walk"). 2.2.9 infers
list<Item>andItem|nullhere.equals()now also compares the conditional expressions. Full test suite passes.Closes phpstan/phpstan#15157