title: Odd error with UIAlertView
body: <p>My code is breaking on something I don't believe I've changed (although that may be naive).</p>
  
  <pre><code>- (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex
  {
      if(buttonIndex==0) //breaks here
      {
          [self performSegueWithIdentifier:@"unwindFromCaseToMain" sender:self];
      }
  
  }
  </code></pre>
  
  <p>This is the error, from a method which seemed to be working fine before and I'm almost certain I didn't change.</p>
  
  <p><img src="https://i.stack.imgur.com/T4RQE.png" alt="enter image description here"></p>
  
  <p>The code doesn't have any warnings or errors, and runs fine until I use the UIAlertView that calls this method.</p>