title: Accessing the error in Alamofire causes EXC_BAD_ACCESS
body: <p>In my iOS app I have an UIVieController with a text field which sends a request each time the value is edited. The point is to show the user suggestions which are returned from the server as a JSON object.
  I initially had all Alamofire requests run freely but to lighten the load (even though these requests were <em>very</em> lightweight) I added </p>
  
  <pre><code>didSet {
      oldValue?.cancel()
  }
  </code></pre>
  
  <p>to my controller's <code>modalRequest</code> property, which stores the current request.</p>
  
  <p>However now, my response handler throws EXC_BAD_ACCESS (code=1, address=0x0) when trying to access the error in the closure. The code is as follows :</p>
  
  <pre><code>@IBAction func textValueChanged(sender: AnyObject) {
      currentTextField = (sender as UITextField)
  
      if (currentTextField!.text != "") {
          modalRequest = Alamofire.request(.GET, "http://example.org/autocomplete/" + modalType.rawValue, parameters: ["term":currentTextField!.text]).responseJSON {(request, response, json, error) in
              if let error = error {
                  NSLog("Error: \(error)")
                  println(request)
                  println(response)
              } else {
                  let oldCount = self.suggestions.count
                  self.suggestions.removeAll()
                  let suggestionJSON = JSON(json!)
                  for s in suggestionJSON.arrayValue {
                      self.suggestions.append(s["name"].stringValue)
                  }
                  self.tableView.reloadSections(NSIndexSet(index: 1), withRowAnimation: UITableViewRowAnimation.Automatic)
              }
          }
      } else {
          self.modalRequest?.cancel()
          self.suggestions.removeAll()
          self.tableView.reloadSections(NSIndexSet(index: 1), withRowAnimation: UITableViewRowAnimation.Automatic)
      }
  }
  </code></pre>
  
  <p>The weird and worrying part is that when I type quickly, thus canceling uncompleted requests, everything goes swiftly (pun intended), meaning that the console logs all error's as cancelled. However if the text I input contains a space and a previous request is cancelled through quick typing, the logger tries to print the error but throws the EXC_BAD_ACCESS, <strong>even though it's in optional binding</strong>! Shouldn't that ensure that value isn't nil so at least exists?</p>
  
  <p>Have you ever encountered this?</p>
  
  <p>Thank you for your time!</p>
  
  <p><strong>NB</strong>: deleting the line does of course work but I might want to add error handling in the future and this bug is really bugging me</p>