Fix phpstan/phpstan#12062: False positive "has no effect" on call to late static binding method of abstract class#5345
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… call to overridable method - Skip collecting static:: calls in PossiblyPureStaticCallCollector when the method can be overridden - A subclass may override the method with side effects, so the call cannot be assumed pure - Updated existing test expectations for static:: calls in non-final classes - New regression test in tests/PHPStan/Rules/DeadCode/data/bug-12062.php
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Summary
When calling a method via
static::(late static binding) in a non-final class, PHPStan incorrectly reported "Call to ... on a separate line has no effect" even though a subclass could override the method with side effects (e.g., throwing an exception).Changes
src/Rules/DeadCode/PossiblyPureStaticCallCollector.phpto skip collectingstatic::call sites when:tests/PHPStan/Rules/DeadCode/CallToStaticMethodStatementWithoutImpurePointsRuleTest.phpfor the existingstatic::myFunc()test case (line 48)tests/PHPStan/Rules/DeadCode/data/bug-12062.phpRoot cause
The
PossiblyPureStaticCallCollectorresolvedstatic::validateParam()to the base class method and collected it as a possibly-pure call. TheMethodWithoutImpurePointsCollectorthen confirmed the base class method body had no impure points. The cross-reference inCallToStaticMethodStatementWithoutImpurePointsRulematched them, producing the false positive. The fix skips collectingstatic::calls when the method can be overridden, since a subclass might add side effects.Test
Added
tests/PHPStan/Rules/DeadCode/data/bug-12062.phpwith an abstract base class that has a purevalidateParam()method called viastatic::, and a subclass that overrides it to throw an exception. The test expects no errors.Fixes phpstan/phpstan#12062