[swift-evolution] Protocol conformance error

[Saagar Jha]

If we have:

class N: A {}

you can pass an N into C’s test(x:), since N is an A, but not M’s test(x:), since N is not a B. Thus, it’s not a valid conformance.

Saagar Jha

> On Jan 17, 2018, at 00:04, Roshan via swift-evolution <swift-evolution at swift.org> wrote:
> 
> Hi,
> 
> Cross posting from swift-users in case this behaviour isn't part of
> the language and might be interesting to you folks.
> 
> Here is some sample code that gives a protocol conformance error in a
> playground:
> 
> protocol A {}
> protocol B: A {}
> 
> protocol C {
>    func test(x: A)
> }
> 
> class M: C {
>    func test(x: B) {}
> }
> 
> Is there a reason why the compiler doesn't infer that ((B) -> ())
> matches ((A) -> ()) because of inheritance?
> 
> -- 
> Warm regards
> Roshan
> _______________________________________________
> swift-evolution mailing list
> swift-evolution at swift.org
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