Fix phpstan/phpstan#14251: new X() where X is a trait should be reported#5182
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ondrejmirtes merged 1 commit intophpstan:2.1.xfrom Mar 10, 2026
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- Added trait check to InstantiationRule alongside existing checks for enums, interfaces, and abstract classes - New error message: "Cannot instantiate trait X." with identifier "new.trait" - New regression test in tests/PHPStan/Rules/Classes/data/bug-14251.php Closes phpstan/phpstan#14251
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Summary
PHPStan was not reporting an error when trying to instantiate a trait with
new TraitName(). TheInstantiationRulealready checks for enums, interfaces, and abstract classes but was missing a check for traits.Changes
src/Rules/Classes/InstantiationRule.php, before the existing enum/interface/abstract checksnew.traittests/PHPStan/Rules/Classes/data/bug-14251.phpand corresponding test method intests/PHPStan/Rules/Classes/InstantiationRuleTest.phpRoot cause
The
InstantiationRulehad checks forisEnum(),isInterface(), andisAbstract()on the class reflection, but was missing a check forisTrait(). Traits cannot be instantiated in PHP (it produces a fatal error), so PHPStan should report this statically.Test
Added
testBug14251()which verifies thatnew InternalTrait()produces the error "Cannot instantiate trait Bug14251\InternalTrait." at line 9.Fixes phpstan/phpstan#14251