[swift-evolution] Pitch: Deprecate/remove AnyObject method dispatch

Slava Pestov spestov at apple.com
Tue Oct 24 18:06:14 CDT 2017

You can implement an @objc protocol with an optional requirement, and make NSObject conform to it.


> On Oct 24, 2017, at 4:05 PM, Charles Srstka <cocoadev at charlessoft.com> wrote:
>> On Oct 24, 2017, at 5:02 PM, Slava Pestov via swift-evolution <swift-evolution at swift.org <mailto:swift-evolution at swift.org>> wrote:
>> Thoughts? Does anyone actually rely on this feature, instead of just stumbling on it by accident once in a while?
> The main thing I can think of off the top of my head is getting the tag from the sender in an IBAction:
> @IBAction private func someAction(_ sender: Any?) {
>     guard let tag = (sender as AnyObject?)?.tag as Int? else { return }
>     ...
> }
> Unfortunately given how many unrelated Cocoa objects there are that implement -tag, it’s not really practical to implement this without the AnyObject dispatch. If a TagContaining protocol could be introduced and all the objects that implement -tag could be made to conform to it, then that would work around the problem (I believe I pitched this at some point long ago, but without catching any interest).
> Charles

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