Swift: overriding method with selector has incompatible type

Question

I have declared a class method in Objective-C:

+ (id) someFunction:(NSDictionary *)param;

When I subclass the class and override this method in Swift with this:

override class func someFunction(param : NSDictionary) -> AnyObject?

I get the error:

Overriding method with selector 'someFunction:' has incompatible type '(NSDictionary) -> AnyObject?'

How do I override the method correctly?

Nate Cook · Accepted Answer · 2014-10-20 03:01:27Z

3

When I try to autocomplete that class function from somewhere else in Swift, Xcode tells me that param is an [NSObject: AnyObject]!, which makes the method declaration work:

override class func someFunction(param: [NSObject: AnyObject]!) -> AnyObject? {
    return "Foo"
}

This might be a compiler bug, since I'm pretty sure that's supposed to bridge properly to NSDictionary! (it seems to be bridging one way, but not the other, or something).

edited Oct 20, 2014 at 3:01

answered Oct 20, 2014 at 2:31

Nate Cook

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2 Comments

Thomas Over a year ago

Wow, thanks! I did not get any auto-complete suggestions at all, but yours does work. It's no problem to cast the param, so that is a compiler bug I can live with.

bolnad Over a year ago

does appear to be some sort of compiler bug, am running into that a lot myself

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