Compilation failure using mut on a navigation controller about swift-overture

[stephencelis]

Sorry for the delay in any response. Since this doesn't seem to be a bug and more of a UIKit quirk, I'm going to move this to a discussion. The problem would seem to lie in the fact that \.navigationBar is a read-only property, while any writable key path chained along it will become a reference-writable key path.

There may be some key path compositional lessons to learn here, like being able to mver(\.value) where Value: AnyObject, but because that will increase the overload space, let's keep things as a discussion for now.