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

[Richard Eisenberg]

> 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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