Pointer is missing a nullability type specifier

Question

In Xcode 7 GM I started to get this warning:

Pointer is missing a nullability type specifier (_Nonnull, _Nullable, or _Null_unspecified)

Answer 1

You need to specify nullable also for the handlers/blocks

- (void)setObject:(nullable id)value
           forKey:(nonnull NSString *)defaultName
    objectChanged:(nullable void(^)(NSUserDefaults *userDefaults, id value))changeHandler
    objectRamains:(nullable void(^)(NSUserDefaults *userDefaults, id value))remainHandler;

Why? It's due to Swift. Swift allows optional parameters (?), which Objective-C does not. This is done as a bridge between the both of them for the Swift compiler to know those parameters are optional. A 'Nonnull' will tell the Swift compiler that the argument is the required. A nullable that it is optional

For more info read: https://developer.apple.com/swift/blog/?id=25