static void RegisterCustomSubclass(Class subclass, Class superclass)
[gCustomSubclassMap setObject: subclass forKey: superclass];
[gCustomSubclasses addObject: subclass];
Can this warning be ignored?
It may be worth filing a bug about this with Apple. Classes do conform to NSCopying and in fact the docs explicitly call out use as a dictionary keys as a reason for this:
In any case, casting it to id or id<NSCopying> should shut it up.
I had the same problem and spoke to some engineers at WWDC, but didn't get a clear answer. Class is a subclass from NSObject, and NSObject has a private static method called copyWithZone, so everything will work. They recommended using NSStringFromClass or, as @mikeash noted, just casing the problem away with id.