Bug or feature?

[Nicolas Frisby]

I'd be happy to raise a ticket, but it might take a few days -- work trip.

On Tue, May 21, 2019, 01:55 Simon Peyton Jones <simonpj at microsoft.com>
wrote:

> We have to be careful in how we define "equality" in the above sentence,
> including class constraints that (may) have superclass equality constraints.
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> Indeed. That’s what happens now.
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> I do think this would work.
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> Cool.  Nick or Iavor: would you like to turn this conversation into a
> ticket?
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> (Although it is technically user-facing, it is a very small corner and I’m
> not sure it would need a GHC proposal – others may want to comment.)
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> Simon
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> *From:* Richard Eisenberg <rae at cs.brynmawr.edu>
> *Sent:* 21 May 2019 09:43
> *To:* Simon Peyton Jones <simonpj at microsoft.com>
> *Cc:* Nicolas Frisby <nicolas.frisby at gmail.com>; Iavor Diatchki <
> iavor.diatchki at gmail.com>; ghc-devs at haskell.org; Ryan Scott <
> ryan.gl.scott at gmail.com>
> *Subject:* Re: Bug or feature?
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> On May 21, 2019, at 10:23 AM, Simon Peyton Jones via ghc-devs <
> ghc-devs at haskell.org> wrote:
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> But (A) looks sound to me.
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> I like (A). (B) makes me nervous, too.
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> > A. An implication is considered to “bind local equalities” iff it has at
> least one given equality whose free variables are not all bound by the same
> implication.
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> We have to be careful in how we define "equality" in the above sentence,
> including class constraints that (may) have superclass equality
> constraints. I do think this would work.
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> Richard
>
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