Unpacking coercions

[Ryan Scott]

> Simple is good.  But what is this dead simple idea?

I'm referring to David's first e-mail on this thread:
https://mail.haskell.org/pipermail/ghc-devs/2018-September/016191.html

All that would take is putting Coercion in TysWiredIn, and moving Coercion
from Data.Type.Coercion to somewhere in ghc-prim.

> Maybe this thread belongs with the proposal, unless I’m misunderstanding.

I think the intention is to have that proposal (which proposes a language
change) be superseded by this idea (which does not change the language).

Ryan S.


On Wed, Sep 5, 2018 at 10:20 AM, Simon Peyton Jones <simonpj at microsoft.com>
wrote:

> Simple is good.  But what is this dead simple idea?
>
>
>
> Perhaps: https://github.com/ghc-proposals/ghc-proposals/pull/116
>
> But that proposal lists several possible alternatives.  Which one did you
> mean?
>
>
>
> And all of them are language changes. Making evidence strict would require
> no language changes to solve the original problem.
>
>
>
> Maybe this thread belongs with the proposal, unless I’m misunderstanding.
>
>
>
> Simon
>
>
>
> *From:* ghc-devs <ghc-devs-bounces at haskell.org> *On Behalf Of *Ryan Scott
> *Sent:* 05 September 2018 15:15
> *To:* ghc-devs at haskell.org
> *Subject:* Re: Unpacking coercions
>
>
>
> These aren't mutually exclusive ideas. While I'm sure there's many ways we
> could solve this problem, David's idea has the distinct advantage of being
> dead simple. I'd rather not block his vision on some other large refactor
> that may never materialize. (And if it _does_ materialize, we could revert
> any wiring-in of Coercible quite easily.)
>
>
>
> Ryan S.
>
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