[ghc-steering-committee] Please review #259: No kind signatures on associated types Shepherd: Simon PJ

[Spiwack, Arnaud]

I didn't know one could do that. Ah well. Still rare enough a use-case that
I won't complain about this limitation.

On Mon, 9 Sep 2019, 11:31 Richard Eisenberg, <rae at richarde.dev> wrote:

>
>
> On Sep 9, 2019, at 7:49 AM, Spiwack, Arnaud <arnaud.spiwack at tweag.io>
> wrote:
>
> - Associated type declaration are already kind of type signature
> assignments.
> - Except only partial, as some of the variables will be to the left of the
> type families
> - But these extra variables are already mentioned in the type class, where
> their type can be specified. In particular by a kind signature!
>
> So do I need to write `(Type -> Type) -> Type` near a type variable? No, I
> don't.
>
>
> Not that I wish to dampen your enthusiasm for the proposal, but I disagree
> here.
>
> > class C a where
> >   type F a (b :: Type -> Type -> Type)
>
> So, while it's true that we don't need all the Type stuff on the class
> variables, other variables may be included in an associated type and they
> might need kind signatures.
>
> Richard
>
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