More general Generic and Data instances for Data.Proxy.Proxy?

Eric Mertens emertens at
Fri Jul 17 23:20:40 UTC 2015

It appears that this is a simple matter of the PolyKinds extension not
being enabled in libraries/base/GHC/Generics.hs and presumably the reason
is the same for the Data instance.

It doesn't seem particularly controversial generalize those instances.

On Fri, Jul 17, 2015 at 3:06 PM Carl Howells <chowells79 at> wrote:

> At the moment, the following two instances are listed in the haddocks
> for Data.Proxy.Proxy:
>     Data t => Data (Proxy * t)
>     Generic (Proxy * t)
> Do those instances need to be that restrictive?  Would it be possible
> to generalize those instances to these?
>     Data (Proxy k t)
>     Generic (Proxy k t)
> I'm not 100% comfortable with either of those classes, so I'm not sure
> if those instances work right, but it seems like they should in a
> hand-wavy way.
> --
> Carl Howells
> _______________________________________________
> Libraries mailing list
> Libraries at
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <>

More information about the Libraries mailing list