title: C method returning NSString gives 'implicit conversion of 'int' to 'NSString *' is disallowed with ARC' error
body: <p>I have this <code>C</code> method:</p>
  
  <p>.h</p>
  
  <pre><code>NSString *NSStringFromMKMapPoint(MKMapPoint mapPoint);
  </code></pre>
  
  <p>.m</p>
  
  <pre><code>NSString *NSStringFromMKMapPoint(MKMapPoint mapPoint) {
      return [NSString stringWithFormat:@"%i,%i", (int)mapPoint.x, (int)mapPoint.y];
  }
  </code></pre>
  
  <p>Trying to set an NSString using the return value, as so:</p>
  
  <pre><code>NSString *tilePointString = NSStringFromMKMapPoint(tilePoint);
  </code></pre>
  
  <p>is giving me this error:</p>
  
  <blockquote>
    <p>Implicit conversion of 'int' to 'NSString *' is disallowed with ARC</p>
  </blockquote>