[TypeDeclaration] Handle initialized on getter on ReturnTypeFromStric…

…tTypedPropertyRector (#5784)

* Added failling test

* update fixture

* Fixes #5775

---------

Co-authored-by: Markus Staab <[email protected]>

rules-tests/TypeDeclaration/Rector/ClassMethod/ReturnTypeFromStrictTypedPropertyRector/Fixture/initialized_in_getter.php.inc

@@ -0,0 +1,39 @@
+<?php
+
+namespace Rector\Tests\TypeDeclaration\Rector\ClassMethod\ReturnTypeFromStrictTypedPropertyRector\Fixture;
+
+use stdClass;
+
+final class InitializedInGetter
+{
+    private ?stdClass $demo = null;
+
+    public function getDemo() {
+        if ($this->demo === null) {
+            $this->demo = new stdClass();
+        }
+        return $this->demo;
+    }
+}
+
+?>
+-----
+<?php
+
+namespace Rector\Tests\TypeDeclaration\Rector\ClassMethod\ReturnTypeFromStrictTypedPropertyRector\Fixture;
+
+use stdClass;
+
+final class InitializedInGetter
+{
+    private ?stdClass $demo = null;
+
+    public function getDemo(): \stdClass {
+        if ($this->demo === null) {
+            $this->demo = new stdClass();
+        }
+        return $this->demo;
+    }
+}
+
+?>

rules/TypeDeclaration/Rector/ClassMethod/ReturnTypeFromStrictTypedPropertyRector.php

@@ -150,7 +150,7 @@ private function resolveReturnPropertyType(ClassMethod $classMethod): array
                 return [];
             }
 
-            $propertyTypes[] = $phpPropertyReflection->getNativeType();
+            $propertyTypes[] = $this->nodeTypeResolver->getNativeType($return->expr);
         }
 
         return $propertyTypes;