title: Assigning to 'id<UINavigationControllerDelegate,UIImagePickerControllerDelegate>' from incompatible type 'ViewController *const__strong'
body: <p>I have an ImagePickerController in my application.
  It works well, but beside <code>ipc.delegate = self;</code> there appears an error message:</p>
  
  <blockquote>
    <p>Assigning to
    'id'
    from incompatible type 'ViewController *const__strong'</p>
  </blockquote>
  
  <p>The app workes well, so I ignored the error message, but I think I need to know why. Why is the error message appearing?</p>
  
  <pre><code>ipc = [[UIImagePickerController alloc]init];
              ipc.modalPresentationStyle = UIModalPresentationCurrentContext;
              ipc.delegate = self;
              ipc.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;
              [ipc setAllowsEditing:NO];
              [self presentViewController:ipc animated:NO completion:nil];
  </code></pre>