title: Type does not conform to protocol, but it does - migrating to Swift 3
body: <p>I'm migrating my app to Swift 3 and I encountered this problem. Been stuck for hours and nothing seems to help</p>
  
  <p><a href="https://i.stack.imgur.com/HVjZd.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/HVjZd.png" alt="enter image description here"></a></p>
  
  <p>Here's my code, it's visible that I'm complying with the protocol.</p>
  
  <pre><code>func loginButtonWillLogin(_ loginButton: FBSDKLoginButton!) -&gt; Bool {
      return true;
  }
  
  func loginButtonDidLogOut(_ loginButton: FBSDKLoginButton!) {
  }
  
  func loginButton(_ loginButton: FBSDKLoginButton!, didCompleteWith result: FBSDKLoginManagerLoginResult!, error: Error!) {
  
      if (error != nil){
  
      } else if (result.isCancelled){
  
      } else {
          navigationController?.pushViewController(ContainerScreen(), animated: false);
      }
  }
  </code></pre>
  
  <p>Anything that I can try to move forward? Thank you.</p>