title: Make IDEA detect unresolved attributes in a decorated class
body: <p>I've got a decorator which returns its argument unchanged, that is <code>Deco(cls) == cls</code>. IDEA (most recent version) fails to report unresolved attributes on a decorated class.</p>
  <p>I guess I have to provide some clever type hinting for <code>Deco</code>. How would that look exactly?</p>
  <pre><code>class A:
      def foo(self):
          print(self)
  
  
  A().foo()
  A().no_such_thing()  # red line, correct
  
  
  class Deco:
      def __call__(self, cls):
          return cls
  
  
  @Deco()
  class B:
      def foo(self):
          print(self)
  
  
  B().foo()
  B().no_such_thing()  # no red line, WRONG
  </code></pre>
  <p><a href="https://i.stack.imgur.com/8HuGt.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/8HuGt.png" alt="enter image description here" /></a></p>