Fix phpstan/phpstan#13981: Assignment inside match statement no longer recognized#5120
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Fix phpstan/phpstan#13981: Assignment inside match statement no longer recognized#5120phpstan-bot wants to merge 3 commits intophpstan:2.1.xfrom
phpstan-bot wants to merge 3 commits intophpstan:2.1.xfrom
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- Variable assignments in match arm conditions (e.g. `is_dir($baseDir = ...)`) were lost after commit 3beb8c6 replaced processExprNode with filterByTruthyValue - filterByTruthyValue only narrows types without walking the AST, so assignments within condition expressions were not discovered for the arm body scope - Fix transfers newly-defined variables from the condition processing scope to the body scope after applying truthiness filtering - New regression test in tests/PHPStan/Rules/Variables/data/bug-13981.php Closes phpstan/phpstan#13981
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Summary
Assignment inside match arm conditions (e.g.,
is_dir($baseDir = dirname(__DIR__).'/lang') => $baseDir) stopped being recognized in PHPStan 2.1.34, causing false positive "Variable $baseDir might not be defined" errors. This fix restores correct variable scoping for match arm bodies.Changes
src/Analyser/NodeScopeResolver.phpto transfer newly-defined variables from the condition processing scope to the arm body scope afterfilterByTruthyValueis applieduse function array_flipimport for efficient variable lookup$armCondResultScopebefore the condition loop to track the scope after condition processingtests/PHPStan/Rules/Variables/data/bug-13981.phptestBug13981intests/PHPStan/Rules/Variables/DefinedVariableRuleTest.phpRoot cause
Commit
3beb8c626("Fix match analysis") changed how the match arm body scope is computed from$this->processExprNode($stmt, $filteringExpr, ...)->getTruthyScope()to$matchScope->filterByTruthyValue($filteringExpr). WhileprocessExprNodewalks the AST and discovers variable assignments,filterByTruthyValueonly performs type narrowing without AST traversal. This meant that any variable assignments occurring as side effects inside match arm conditions (like$baseDir = dirname(__DIR__).'/lang'insideis_dir(...)) were no longer carried into the arm body scope.The fix detects variables that are newly defined in the condition processing scope (not present in
$matchScope) and explicitly transfers them to the body scope.Test
Added
tests/PHPStan/Rules/Variables/data/bug-13981.phpwhich reproduces the exact scenario from the issue: a match expression withis_dir($baseDir = dirname(__DIR__).'/lang') => $baseDir. The test expects no errors, confirming that the variable assignment in the condition is properly recognized in the arm body.Fixes phpstan/phpstan#13981