First time seeing this error, can't i put '!' after 'as' in swift? Or just bug after updating my Xcode to 6.2?
let url = notification.userInfo![CallbackNotification.optionsURLKey] as! NSURL
It shows error : Expected type after 'as'
P.S: You can try download OAuthSwift from github to test this error. https://github.com/dongri/OAuthSwift