[swift-evolution] [Proposal] Allow Static Function Properties to Satisfy Static Function Protocol Requirements

[Jasdev Singh]

Hey Chris, thanks so much for the feedback!

> This is an additive proposal, thus out of scope for Swift 3.

For sure! Definitely didn’t expect this to land pre-3.0 :)

> Beyond that, as someone down thread mentioned, the major thing missing
here is a strong motivation for *why* we should do this.

I should’ve added more color to the motivation. The idea for this proposal
sparked from a conversation w/ Joe Groff

<https://twitter.com/jasdev/status/751875707375120385>
<https://twitter.com/jasdev/status/751875707375120385>
https://twitter.com/jasdev/status/751875707375120385
<https://twitter.com/jasdev/status/751875816896786432>
https://twitter.com/jasdev/status/751875816896786432

I was attempting to use rdar://19091028 as a way to create protocol that
can be shared across enums to guarantee the presence of a specific case.
For example, imagine we wanted a series of enumerations that could wrap an
`NSError` like so
https://gist.github.com/Jasdev/9baeb146381cd2ba511125ab8b0e88a0

This could be helpful when returning a `Result` from a function that has an
intermediary step that could throw an `NSError`. With such an ability, we
could keep the functions return type to be `Result<T, SomeOtherError>` for
some `T` (and `SomeOtherError` from the gist mentioned before) w/o having
to make the returned error less specific (i.e. a plain `NSError`).

Hope this adds some clarity!

On Mon, Jul 11, 2016 at 6:43 PM Chris Lattner <clattner at apple.com> wrote:

>
> On Jul 11, 2016, at 3:39 PM, Chris Lattner via swift-evolution <
> swift-evolution at swift.org> wrote:
>
>
> On Jul 10, 2016, at 1:33 PM, Jasdev Singh via swift-evolution <
> swift-evolution at swift.org> wrote:
>
> Hey Swift Evolution!
>
> Drafted up a small proposal that harmonizes the use of static functions
> and static function properties in appropriate protocol conformance
> scenarios:
>
>
> https://github.com/Jasdev/swift-evolution/blob/static-func-static-var/proposals/XXXX-static-func-and-static-var-func-protocol-conformance.md
>
> Would love any feedback or edge cases I may have missed!
>
>
> This is an additive proposal, thus out of scope for Swift 3.
>
> Beyond that, as someone downthread mentioned, the major thing missing here
> is a strong motivation for *why* we should do this.  You say only "we see
> that the protocol requirements and conformances are actually equivalent and
> should both be valid.” but adding redundant ways to say the same thing
> motivation.
>
>
> I meant: "but adding redundant ways to say the same thing is not a
> motivation.”
>
> -Chris
>
> --
@jasdev
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