We have to be careful in how we define "equality" in the above sentence, including class constraints that (may) have superclass equality constraints.
Indeed. That’s what happens now. I do think this would work. Cool. Nick or Iavor: would you like to turn this conversation into a ticket? (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.) Simon From: Richard Eisenberg <[email protected]> Sent: 21 May 2019 09:43 To: Simon Peyton Jones <[email protected]> Cc: Nicolas Frisby <[email protected]>; Iavor Diatchki <[email protected]>; [email protected]; Ryan Scott <[email protected]> Subject: Re: Bug or feature? On May 21, 2019, at 10:23 AM, Simon Peyton Jones via ghc-devs <[email protected]<mailto:[email protected]>> wrote: But (A) looks sound to me. I like (A). (B) makes me nervous, too. > 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. 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. Richard
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