[DeadCode] Remove unused @return mixed on RemoveUselessReturnTagRector (

#5332)

* [DeadCode] Remove unused @return mixed on RemoveUselessReturnTagRector

* implemented 🎉

* more fixture

rules-tests/DeadCode/Rector/ClassMethod/RemoveUselessReturnTagRector/Fixture/remove_return_mixed.php.inc

@@ -0,0 +1,34 @@
+<?php
+
+namespace Rector\Tests\DeadCode\Rector\ClassMethod\RemoveUselessReturnTagRector\Fixture;
+
+use stdClass;
+
+class RemoveReturnMixed
+{
+    /**
+     * @return mixed
+     */
+    function foo(): stdClass
+    {
+        return new stdClass();
+    }
+}
+
+?>
+-----
+<?php
+
+namespace Rector\Tests\DeadCode\Rector\ClassMethod\RemoveUselessReturnTagRector\Fixture;
+
+use stdClass;
+
+class RemoveReturnMixed
+{
+    function foo(): stdClass
+    {
+        return new stdClass();
+    }
+}
+
+?>

rules-tests/DeadCode/Rector/ClassMethod/RemoveUselessReturnTagRector/Fixture/remove_return_mixed2.php.inc

@@ -0,0 +1,30 @@
+<?php
+
+namespace Rector\Tests\DeadCode\Rector\ClassMethod\RemoveUselessReturnTagRector\Fixture;
+
+class RemoveReturnMixed2
+{
+    /**
+     * @return mixed
+     */
+    function foo(): mixed
+    {
+        return null;
+    }
+}
+
+?>
+-----
+<?php
+
+namespace Rector\Tests\DeadCode\Rector\ClassMethod\RemoveUselessReturnTagRector\Fixture;
+
+class RemoveReturnMixed2
+{
+    function foo(): mixed
+    {
+        return null;
+    }
+}
+
+?>

rules/DeadCode/PhpDoc/DeadReturnTagValueNodeAnalyzer.php

@@ -51,10 +51,6 @@ public function isDead(ReturnTagValueNode $returnTagValueNode, ClassMethod|Funct
             return false;
         }
 
-        if (! $this->hasUsefullPhpdocType($returnTagValueNode, $returnType)) {
-            return true;
-        }
-
         if (! $this->typeComparator->arePhpParserAndPhpStanPhpDocTypesEqual(
             $returnType,
             $returnTagValueNode->type,
@@ -98,6 +94,10 @@ private function isDeadNotEqual(ReturnTagValueNode $returnTagValueNode, Node $no
             return true;
         }
 
+        if (! $this->hasUsefullPhpdocType($returnTagValueNode, $node)) {
+            return true;
+        }
+
         $nodeType = $this->staticTypeMapper->mapPhpParserNodePHPStanType($node);
         $docType = $this->staticTypeMapper->mapPHPStanPhpDocTypeNodeToPHPStanType(
             $returnTagValueNode->type,
@@ -129,10 +129,14 @@ private function hasTrueFalsePseudoType(BracketsAwareUnionTypeNode $bracketsAwar
     }
 
     /**
-     * in case of void,never there is no added value in "@return tag"
+     * exact different between @return and node return type
      */
     private function hasUsefullPhpdocType(ReturnTagValueNode $returnTagValueNode, mixed $returnType): bool
     {
+        if ($returnTagValueNode->type instanceof IdentifierTypeNode && $returnTagValueNode->type->name === 'mixed') {
+            return false;
+        }
+
         if (! $this->isVoidReturnType($returnType)) {
             return ! $this->isNeverReturnType($returnType);
         }