fix: use strict mixed in StrictTypeSafetyChecker

Author: calebdw

phpstan.neon

@@ -68,6 +68,9 @@ parameters:
         # phpstan class constant value
         - identifier: phpstanApi.classConstant
 
+        # phpstan class construction
+        - identifier: phpstanApi.constructor
+
         # phpstan instanceof
         - identifier: phpstanApi.instanceofAssumption
 

rules/TypeDeclaration/NodeAnalyzer/StrictTypeSafetyChecker.php

@@ -18,6 +18,7 @@
 use PHPStan\Reflection\Php\PhpPropertyReflection;
 use PHPStan\Type\MixedType;
 use PHPStan\Type\NeverType;
+use PHPStan\Type\StrictMixedType;
 use PHPStan\Type\Type;
 use Rector\NodeTypeResolver\NodeTypeResolver;
 use Rector\NodeTypeResolver\PHPStan\ParametersAcceptorSelectorVariantsWrapper;
@@ -197,6 +198,11 @@ private function isPropertyAssignSafe(Assign $assign): bool
 
     private function isTypeSafeForStrictMode(Type $declaredType, Type $valueType): bool
     {
+        // need to be strict with mixed to avoid false positives
+        if ($valueType instanceof MixedType) {
+            $valueType = new StrictMixedType();
+        }
+
         return $declaredType->accepts($valueType, strictTypes: true)
             ->yes();
     }