在xcode7上出现CLLocation错误

Question

错误说'CLLocation'中的Downcast？只打开选项;你的意思是用'！'？我该如何解决这个问题？

    func locationManager(manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
   //the code below is the error i got for
    var location = locations.last as! CLLocation

    self.currentLocation = location
    var userInfo = [ LMLocationInfoKey : location]
    NSNotificationCenter.defaultCenter().postNotificationName(LMLocationUpdateNotification as String, object:self, userInfo: userInfo)
    self.locationManager_.stopUpdatingLocation()
}