Nil optional does not crash in Release

问题

I have the following simple code in NSAppDelegate

func applicationDidFinishLaunching(aNotification: NSNotification) {
  var opt:Int?
  NSLog("\(opt)")
  NSLog("\(opt!)")
  NSLog("done")
}

Now when I run that in debug mode it tells me what we all know about unwrapping nil optional. But when I run that for release it silently exits the app with no message at all. No console log. No dump. Nothing!

What's going on here?

回答1:

Apple has asked me to check if the bug has been fixed with Xcode 6.3 beta 3 with Swift 1.2 (Build: 6D543q). Not sure if I really want to test another beta :-/ However, the answer to my question: it's a bug.

Edit Jumped over my own shadow and tested with the last beta (4). Issue has been fixed.

来源：https://stackoverflow.com/questions/29143855/nil-optional-does-not-crash-in-release