swift234

Runtime: Allow value type ErrorTypes to dynamically coerce to NSError.

If we see an ErrorType-conforming value type while casting to NSError, do the coercion in the runtime, so that e.g. 'error as Any as! NSError' works as well as 'error as NSError'.

Unfortunately, we can't do this for ErrorType-conforming classes without shattering SIL's brittle view of the world due to rdar://problem/20507075. Casts between class types are fairly deeply assumed not to change the identity of the reference.

Swift SVN r27225