Weird error overriding a property

[Jens Alfke]

I’m getting an odd compile error in a pretty basic scenario: I’ve got a class hierarchy with a boolean “online” property that’s mutable but not externally settable. A subclass wants to add a ‘didSet’ observer to do something when the value changes:

public class Peer : NSObject {

    public internal(set) dynamic var online = false

}

public class OnlinePeer : Peer {

    public internal(set) override dynamic var online: Bool {  // ERROR!

        didSet {

            println("set online")

        }

    }

}

The error says “Setter of overriding var must be as accessible  as the declaration it overrides”, and the suggestion is to delete “internal (set)”. But this is backwards — the code is correct as written (I think), but removing “internal (set)” would make the setter public, which is different from the inherited access and not what I want.

(The didSet block doesn’t seem to be the source of the problem; I get the same error if I take it out.)

What’s going on here?

—Jens

PS: Xcode 6.3.2, iOS target