Ah, this is a tricky one. When you see a complicated name collision like this, to help the type-checker (as a workaround):

1. First narrow down the type as much as you can, to reduce the scopes that will be looked up, excluding things that you don't want.

2. Pick the right protocol method.

extension UINavigationController: UINavigationBarDelegate {}
class CustomNavigationController: UINavigationController {
    func navigationBar(_ navigationBar: UINavigationBar, shouldPop item: UINavigationItem) -> Bool {
        return (self as UINavigationBarDelegate).navigationBar?(navigationBar, shouldPop: item) ?? true
    }
} 

@swift-ci create

Comment by Andrej Mihajlov (JIRA)

theindigamer (JIRA User) what you suggest creates an infinite loop. I need to call `super` & not `self`.

Oh sorry, made a mistake there. For some reason, using as on super is not permitted, so you can use one level of indirection:

extension UINavigationController: UINavigationBarDelegate {}
extension UINavigationController {
    func customNavigationBar(_ navigationBar: UINavigationBar, shouldPop item: UINavigationItem) -> Bool {
        return (self as UINavigationBarDelegate).navigationBar?(navigationBar, shouldPop: item) ?? true
    }
}
class CustomNavigationController: UINavigationController {
    func navigationBar(_ navigationBar: UINavigationBar, shouldPop item: UINavigationItem) -> Bool {
        return customNavigationBar(navigationBar, shouldPop: item)
    }
} 

It's not ideal, but it does solve the immediate problem (unless I made an error again).

Comment by Andrej Mihajlov (JIRA)

theindigamer (JIRA User) unfortunately that doesn't work either. `self` within category points to `CustomNavigationController`, so it creates an infinite recursion once again. The only solution that worked so far was to use method swizzling.