I had this code with a completion handler working in Xcode 6 beta 4 that no longer works in Xcode 6 beta 5.
dropsToRemove.bridgeToObjectiveC().makeObjectsPer
Someone from Apple has stated that those bridgeToObjectiveC and bridgeFromObjectiveC functions are meant as private functions, i.e. for Apple internal use only, and that they would go away.
I will try to find the link to that statement in the developer forums, if you happen to be in the developer program.