[NSObject : AnyObject]?' does not have a member named 'subscript' in Xcode 6 Beta 6

Question

I am building an app in Xcode 6 Beta 6 in Swift and I keep getting this error:

[NSObject : AnyObject]?\' does not have a member named \'subscript\'

Answer 1

The error message is saying you can't do [] on Optional value. What you need to do is unwrap it.

error.userInfo!["error"] as NSString

or if you want to be safe

if let errorString = error.userInfo?["error"] as NSString {
     println(errorString)
}