Fix phpstan/phpstan#11488: Wrongly assumed undefined variable since 1.11.10#5150
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Fix phpstan/phpstan#11488: Wrongly assumed undefined variable since 1.11.10#5150phpstan-bot wants to merge 1 commit intophpstan:2.1.xfrom
phpstan-bot wants to merge 1 commit intophpstan:2.1.xfrom
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- Added targeted handling in resolveNormalizedIdentical for falsey context
with unions of multiple constant arrays to avoid TypeCombinator::remove
issues caused by supertype relationships between constant array types
- New regression test in tests/PHPStan/Analyser/nsrt/bug-11488.php
- The root cause was that array{mixed} is a supertype of array{mixed,
string|null, mixed}, so TypeCombinator::remove incorrectly eliminated
all union members when negating count() === N comparisons
Closes phpstan/phpstan#11488
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Summary
When using
count($row) !== Non a union of constant arrays likearray{mixed}|array{mixed, string|null, mixed}, PHPStan incorrectly narrowed the type to*NEVER*instead of filtering out the array member that matches the count. This caused false positives about undefined variables from destructured assignments.Changes
src/Analyser/TypeSpecifier.phpinresolveNormalizedIdentical()for the falsey context when the argument is a union of multiple constant arrayssetAlwaysOverwriteTypes()to bypass the problematicTypeCombinator::removebehaviortests/PHPStan/Analyser/nsrt/bug-11488.phpRoot cause
The bug was introduced when
specifyTypesForCountFuncCall()was added toresolveNormalizedIdentical(). In the falsey context (e.g.,count($row) !== 1), the method builds a type representing arrays that match the count, then usesTypeCombinator::removeto subtract it from the original union. However,array{mixed}(a 1-element constant array with a mixed value) is considered a supertype ofarray{mixed, string|null, mixed}(a 3-element array) because mixed accepts all values and extra keys don't prevent the supertype relationship. This causedTypeCombinator::removeto eliminate ALL union members, producing*NEVER*.The fix adds a pre-check specifically for the falsey context with unions of multiple constant arrays. It directly filters out union members whose sizes exactly match the comparison value and uses
setAlwaysOverwriteTypes()to set the result type directly, avoiding the supertype-relatedTypeCombinator::removeissue.Test
Added
tests/PHPStan/Analyser/nsrt/bug-11488.phpwhich tests thatcount($row) !== 1onarray{mixed}|array{mixed, string|null, mixed}correctly narrows toarray{mixed, string|null, mixed}, and that destructured variables from the narrowed array have correct types.Fixes phpstan/phpstan#11488