Swift: declaration 'description' cannot override more than one superclass declaration

Question

I have a structure of inheritance similar to the one below. I\'m adopting the Printable protocol and diligently override description property. I have encountered a bizarre error

Answer 1

I had the same problem with SKTiled when overriding SKTiledScene. In my situation I wanted to override a mouse event for OS X.

The error was as follows:

Declaration 'mouseUp(with:)' cannot override more than one superclass declaration

The problem here is that the mouse events are declared in a class extension:

#if os(macOS)
extension SKTiledScene {

    override open func mouseDown(with event: NSEvent) {}

    override open func mouseMoved(with event: NSEvent) {
        guard let cameraNode = cameraNode else { return }
        cameraNode.mouseMoved(with: event)
    }
    override open func mouseUp(with event: NSEvent) {}
    override open func mouseEntered(with event: NSEvent) {}
    override open func mouseExited(with event: NSEvent) {}

    override open func scrollWheel(with event: NSEvent) {
        guard let cameraNode = cameraNode else { return }
        cameraNode.scrollWheel(with: event)
    }
}
#endif

I could solve my issue to override the method in my own SKTiledScene subclass by re-implementing the extension:

extension SKTiledScene {
    open override func mouseUp(with event: NSEvent) {
        try! SceneManager.shared.transitionToScene(MainMenuScene.self, withAnimation: .fade)
    }
}

I do wonder if I can be sure my extension is always loaded instead of the one from the SKTiled framework, but it seems to work well for now.