title: openURL in APPDelegate conversion error NSString -> String (Swift & iOS8)
body: <p>I'm currently developing an iOS application that integrates Facebook and I'm having a bit of a problem while investigating this with Swift (with ObjC I have no problems).</p>
  
  <p>The thing is, this is the method that gets executed in the appDelegate when coming from another APP (in this case FB in a WebBrowser):</p>
  
  <pre><code>func application(
      application: UIApplication,
      openURL url: NSURL,
      sourceApplication: NSString,
      annotation: AnyObject)
      -&gt; Bool { 
         let appString : String = sourceApplication as String // Try to convert format =&gt; EXCEPTION
         let appString : String = String(sourceApplication)   // 'SSS' Suggestion: EXCEPTION
         println(sourceApplication) // Try to print the value =&gt; EXCEPTION
         return FBAppCall.handleOpenURL(url, sourceApplication:sourceApplication,
              withSession:session) // With Parse =&gt; EXCEPTION
  }
  </code></pre>
  
  <p>And inside that method I'm having real trouble with the 'sourceApplication' parameter. I try to use it, I get an exception. I try to convert it, another exception...can't even log its value because it crashes when accessing its value. Changing the parameter type in the functions signature to String neither worked.</p>
  
  <p>This is the error I'm getting:</p>
  
  <p><code>EXEC_BAD_ACCESS</code></p>
  
  <p>And I've been able to track down until I could read this that it's definitely a valuable hint:</p>
  
  <p><code>ObjectiveC.NSString.__conversion (ObjectiveC.NSString)() -&gt; Swift.String</code></p>
  
  <p>Could it be an iOS8 bug? 
  Any of you has had this problem and/or knows how to solve it? </p>