Fix issues found with cppcheck inconclusive

unittests/object_lifetime_test2.cpp

@@ -20,10 +20,11 @@ struct Vector2
     return Vector2(*this += vec_r);
   }
 
-  void operator=(const Vector2& ver_r)
+  Vector2 &operator=(const Vector2& ver_r)
   {
     x = ver_r.x;
     y = ver_r.y;
+    return *this;
   }