<div dir="ltr"><div>Dear Committee, <br></div><div><br></div><div>I'm happy to repeat my recommendation to accept Alejandro's proposal which is now back from revision:<br></div>Fine-grained pragmas for classes, families, and instances<br><div><div><a href="https://github.com/ghc-proposals/ghc-proposals/pull/390" rel="noreferrer" target="_blank">https://github.com/ghc-proposals/ghc-proposals/pull/390</a><br><a href="https://github.com/serras/ghc-proposals/blob/instance-pragmas/proposals/0000-fine-grained-undecidable.md" rel="noreferrer" target="_blank">https://github.com/serras/ghc-proposals/blob/instance-pragmas/proposals/0000-fine-grained-undecidable.md</a></div><div><br></div><div>All the issues that arose in the previous discussion are now resolved. Does anyone have something to add? <br></div><div><br></div><div>Vitaly<br></div><div><br></div><div><br></div></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">сб, 13 мар. 2021 г. в 12:38, Vitaly Bragilevsky <<a href="mailto:bravit111@gmail.com">bravit111@gmail.com</a>>:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div dir="ltr"></div><div class="gmail_quote"><div dir="ltr" class="gmail_attr">чт, 11 мар. 2021 г. в 16:31, Vladislav Zavialov (int-index) <<a href="mailto:vlad.z.4096@gmail.com" target="_blank">vlad.z.4096@gmail.com</a>>:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">I like the proposal and I would be happy to vote for its acceptance. However, it requires a little bit of polishing up with regards to its use of modifiers. In particular, it seems to treat modifiers as built-in units, whereas the core idea behind modifiers is that they are based on actual promoted types (with the exception of %1).<br>
<br>
Hence it seems appropriate to send it back for revision until this point is addressed.<br></blockquote><div><br></div>Yes, I agree. There is also another issue. I think we need either a deprecation story for UndecidableInstances, or a statement that it should survive with some motivation behind that. <div><br></div><div>So, I'm sending this proposal back to Alejandro for review and set the "needs revision" label on GitHub.</div><div><br></div><div>Vitaly </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<br>
- Vlad<br>
<br>
> On 20 Feb 2021, at 14:34, Vitaly Bragilevsky <<a href="mailto:bravit111@gmail.com" target="_blank">bravit111@gmail.com</a>> wrote:<br>
> <br>
> Dear Committee,<br>
> <br>
> Our own Alejandro has been proposed<br>
> Fine-grained pragmas for classes, families, and instances<br>
> <a href="https://github.com/ghc-proposals/ghc-proposals/pull/390" rel="noreferrer" target="_blank">https://github.com/ghc-proposals/ghc-proposals/pull/390</a><br>
> <a href="https://github.com/serras/ghc-proposals/blob/instance-pragmas/proposals/0000-fine-grained-undecidable.md" rel="noreferrer" target="_blank">https://github.com/serras/ghc-proposals/blob/instance-pragmas/proposals/0000-fine-grained-undecidable.md</a><br>
> <br>
> His idea is to bring the flexibility of overlaps/overlapping/overlappable pragmas to termination checking, type inference, and constraint solving. Alejandro proposes to introduce the following %-modifiers (as in already accepted #370, <a href="https://github.com/ghc-proposals/ghc-proposals/blob/master/proposals/0370-modifiers.rst" rel="noreferrer" target="_blank">https://github.com/ghc-proposals/ghc-proposals/blob/master/proposals/0370-modifiers.rst</a>):<br>
> %NoTerminationCheck<br>
> %LiberalCoverage<br>
> %LiberalInjectivity<br>
> %Overlapping<br>
> %Overlappable<br>
> %Overlaps<br>
> to liberate conditions for classes and instances, type families, forall-types, etc. The first three modifiers can be used instead of the scary-sounding UndecidableInstances extension. The last three modifiers are supposed to be used instead of the  overlap*-pragmas for instances we already have. Note that this proposal doesn't suggest deprecating those extensions and pragmas.<br>
> <br>
> I think that this proposal goes in the right direction and recommend accepting it.<br>
> <br>
> As far as I understand, all the committee members, including those with terms about to expire, have the right to either support this proposal or to raise a voice against it either here or at <a href="https://github.com/ghc-proposals/ghc-proposals/pull/390" rel="noreferrer" target="_blank">https://github.com/ghc-proposals/ghc-proposals/pull/390</a>.<br>
> <br>
> Regards,<br>
> Vitaly<br>
> <br>
> <br>
> <br>
> _______________________________________________<br>
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<br>
</blockquote></div></div>
</blockquote></div>