<html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class="">It has been two weeks. I have heard no argument against this proposal, but Simon Marlow (in the springtime) expressed some puzzlement. Simon, what are you thinking about this now? With no further response, I will accept this proposal on Friday.<div class=""><br class=""></div><div class="">Others are also very welcome to chime in!</div><div class=""><br class=""></div><div class="">Thanks, all!</div><div class="">Richard</div><div class=""><div><br class=""><blockquote type="cite" class=""><div class="">On Oct 27, 2021, at 5:30 AM, Spiwack, Arnaud <<a href="mailto:arnaud.spiwack@tweag.io" class="">arnaud.spiwack@tweag.io</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><div dir="ltr" class="">I think that the proposal makes a great job at listing the issues. It's quite transparent about this, I'm not sure what I could add.<br class=""></div><br class=""><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Wed, Oct 27, 2021 at 11:29 AM Simon Peyton Jones <<a href="mailto:simonpj@microsoft.com" class="">simonpj@microsoft.com</a>> wrote:<br class=""></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">I was indeed confused! Apologies.<br class="">
<br class="">
But my main point remains: enumerating a list of inconvenient side effects and corner cases would be a great service.<br class="">
<br class="">
Simon<br class="">
<br class="">
PS: I am leaving Microsoft at the end of November 2021, at which point <a href="mailto:simonpj@microsoft.com" target="_blank" class="">simonpj@microsoft.com</a> will cease to work. Use <a href="mailto:simon.peytonjones@gmail.com" target="_blank" class="">simon.peytonjones@gmail.com</a> instead. (For now, it just forwards to <a href="mailto:simonpj@microsoft.com" target="_blank" class="">simonpj@microsoft.com</a>.)<br class="">
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| -----Original Message-----<br class="">
| From: Vladislav Zavialov (int-index) <<a href="mailto:vlad.z.4096@gmail.com" target="_blank" class="">vlad.z.4096@gmail.com</a>><br class="">
| Sent: 27 October 2021 10:10<br class="">
| To: Simon Peyton Jones <<a href="mailto:simonpj@microsoft.com" target="_blank" class="">simonpj@microsoft.com</a>><br class="">
| Cc: Spiwack, Arnaud <<a href="mailto:arnaud.spiwack@tweag.io" target="_blank" class="">arnaud.spiwack@tweag.io</a>>; Richard Eisenberg<br class="">
| <<a href="mailto:rae@richarde.dev" target="_blank" class="">rae@richarde.dev</a>>; ghc-steering-committee <ghc-steering-<br class="">
| <a href="mailto:committee@haskell.org" target="_blank" class="">committee@haskell.org</a>><br class="">
| Subject: Re: [ghc-steering-committee] Proposal #281: Visible "forall"<br class="">
| in terms; rec: accept<br class="">
| <br class="">
| Simon, perhaps you’re thinking of another proposal that is currently<br class="">
| under committee’s consideration?<br class="">
| <br class="">
| Arnaud was commenting on #281, and you seem to be talking about #425.<br class="">
| <br class="">
| - Vlad<br class="">
| <br class="">
| > On 27 Oct 2021, at 12:05, Simon Peyton Jones via ghc-steering-<br class="">
| committee <<a href="mailto:ghc-steering-committee@haskell.org" target="_blank" class="">ghc-steering-committee@haskell.org</a>> wrote:<br class="">
| ><br class="">
| > There are a lot of inconvenient side effects and corner cases<br class="">
| ><br class="">
| > Arnaud, could you enumerate them? Even if (as I strongly hope) we<br class="">
| accept this proposal, it’s good to have a concrete list of things to<br class="">
| bear in mind. I for one do not have such list in my head.<br class="">
| ><br class="">
| > One principle that the proposal espouses (but perhaps does not call<br class="">
| out explicitly) is that it should be possible to write an explicit<br class="">
| binder for every in-scope variable. So instead of<br class="">
| > data T (a :: k -> k) = … I want to write<br class="">
| > data T @k (a :: k -> k) = … with an explicit binder<br class="">
| > for k.<br class="">
| ><br class="">
| > So I see the proposal as removing an ad-hoc wart in the language.<br class="">
| But I may be blind to the “inconvenient side effects and corner cases”<br class="">
| and I’d welcome a list of such cases.<br class="">
| ><br class="">
| > Simon<br class="">
| ><br class="">
| ><br class="">
| > PS: I am leaving Microsoft at the end of November 2021, at which<br class="">
| point<br class="">
| > <a href="mailto:simonpj@microsoft.com" target="_blank" class="">simonpj@microsoft.com</a> will cease to work.<br class="">
| > <a href="mailto:Usesimon.peytonjones@gmail.com" target="_blank" class="">Usesimon.peytonjones@gmail.com</a> instead. (For now, it just forwards<br class="">
| to<br class="">
| > <a href="mailto:simonpj@microsoft.com" target="_blank" class="">simonpj@microsoft.com</a>.)<br class="">
| ><br class="">
| > From: ghc-steering-committee<br class="">
| > <<a href="mailto:ghc-steering-committee-bounces@haskell.org" target="_blank" class="">ghc-steering-committee-bounces@haskell.org</a>> On Behalf Of Spiwack,<br class="">
| > Arnaud<br class="">
| > Sent: 27 October 2021 09:20<br class="">
| > To: Richard Eisenberg <<a href="mailto:rae@richarde.dev" target="_blank" class="">rae@richarde.dev</a>><br class="">
| > Cc: ghc-steering-committee <<a href="mailto:ghc-steering-committee@haskell.org" target="_blank" class="">ghc-steering-committee@haskell.org</a>><br class="">
| > Subject: Re: [ghc-steering-committee] Proposal #281: Visible<br class="">
| "forall"<br class="">
| > in terms; rec: accept<br class="">
| ><br class="">
| > I've been struggling to have an opinion on this PR. I'm very<br class="">
| sympathetic to the goal of the proposal (and this latest rendition of<br class="">
| the proposal is a really good document). There are a lot of<br class="">
| inconvenient side effects and corner cases (but, to be fair, these are<br class="">
| not special to this proposal: they are inherent to the dependent types<br class="">
| plan). But I'm fairly convinced that this is the best possible<br class="">
| approach, or close enough.<br class="">
| ><br class="">
| ><br class="">
| ><br class="">
| > So yes, I don't really feel strongly about it. But on balance, I<br class="">
| think that I'm in favour.<br class="">
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