[NodeTypeResolver] Apply logic Mixed inside Union check on TypeFactory::createUnionOrSingleType()

Author: samsonasik

rules/TypeDeclaration/NodeAnalyzer/CallTypesResolver.php

@@ -129,12 +129,6 @@ private function unionToSingleType(array $staticTypesByArgumentPosition, bool $r
 
             if ($staticTypeByArgumentPosition[$position] instanceof UnionType) {
                 foreach ($staticTypeByArgumentPosition[$position]->getTypes() as $subType) {
-                    // has another type over mixed is not allowed, even on native type
-                    if ($subType instanceof MixedType) {
-                        $staticTypeByArgumentPosition[$position] = new MixedType();
-                        continue 2;
-                    }
-
                     if ($removeMixedArray && $subType instanceof ArrayType && $this->isArrayMixedMixedType($subType)) {
                         $staticTypeByArgumentPosition[$position] = new MixedType();
                         continue 2;

src/NodeTypeResolver/PHPStan/Type/TypeFactory.php

@@ -168,6 +168,12 @@ private function createUnionOrSingleType(array $types): Type
             return $types[0];
         }
 
+        foreach ($types as $type) {
+            if ($type instanceof MixedType) {
+                return new MixedType();
+            }
+        }
+
         return new UnionType($types);
     }