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<p class="MsoNormal"><span style="mso-fareast-language:EN-US">I don’t feel strongly about this one. Happy to accept Richard’s recommendation.<o:p></o:p></span></p>
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Simon<o:p></o:p></span></p>
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<p class="MsoNormal"><b><span lang="EN-US">From:</span></b><span lang="EN-US"> ghc-steering-committee <ghc-steering-committee-bounces@haskell.org>
<b>On Behalf Of </b>Richard Eisenberg<br>
<b>Sent:</b> 22 April 2021 03:10<br>
<b>To:</b> Vladislav Zavialov (int-index) <vlad.z.4096@gmail.com><br>
<b>Cc:</b> Simon Peyton Jones via ghc-steering-committee <ghc-steering-committee@haskell.org><br>
<b>Subject:</b> Re: [ghc-steering-committee] #371: Stop treating ~ magically. Rec: weak accept<o:p></o:p></span></p>
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<p class="MsoNormal">Hi committee,<o:p></o:p></p>
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<p class="MsoNormal">This proposal has been updated to include exporting (~) from the Prelude. This means that migration is much easier than it was previously, likely not requiring any import changes (or just in a project's custom Prelude). Users will have
to enable -XTypeOperators (and could choose to disable -XGADTs or -XTypeFamilies). With this new export, I'm more firmly in favor of cleaning up this one little corner: let's accept.<o:p></o:p></p>
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<p class="MsoNormal">I will wait one week for any comments, and then will accept this proposal.<o:p></o:p></p>
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<p class="MsoNormal">Thanks,<o:p></o:p></p>
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<p class="MsoNormal">Richard<o:p></o:p></p>
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<p class="MsoNormal">On Apr 1, 2021, at 2:37 PM, Richard Eisenberg <<a href="mailto:rae@richarde.dev">rae@richarde.dev</a>> wrote:<o:p></o:p></p>
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<p class="MsoNormal">On Apr 1, 2021, at 3:59 AM, Vladislav Zavialov (int-index) <<a href="mailto:vlad.z.4096@gmail.com">vlad.z.4096@gmail.com</a>> wrote:<o:p></o:p></p>
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<p class="MsoNormal"><span style="font-size:8.5pt;font-family:"Menlo-Regular",serif">Exporting from Prelude is not a panacea: without a compatibility fallback, users of custom preludes will be affected. The proposed migration story means that for 8 releases,
no existing code will break at all.</span><o:p></o:p></p>
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<p class="MsoNormal">Right. I wasn't suggesting a change to the migration plan -- just that (~) would additionally be exported from the Prelude. The warning would trigger only when (~) isn't in scope, meaning that many users won't need to react to this change
(given that -XTypeOperators is now on by default).<o:p></o:p></p>
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<p class="MsoNormal">As for the specialness of ~: yes, it's special, but we export other special things from the Prelude, like $ (which automatically enables -XImpredicativeTypes).<o:p></o:p></p>
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<p class="MsoNormal">On Apr 1, 2021, at 9:59 AM, Alejandro Serrano Mena <<a href="mailto:trupill@gmail.com">trupill@gmail.com</a>> wrote:<o:p></o:p></p>
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<p class="MsoNormal">I meant the usual convention that type constructors must start with a capital letter or the : symbol. But in this case I had forgotten that with TypeOperators on, those conventions behave differently for types than for terms.<o:p></o:p></p>
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<p class="MsoNormal">This used to be true, but the requirement that the first letter be a capital letter or : was dropped some time ago -- before I started using Haskell, in any case. It is independent of -XTypeOperators, which is necessary for any infix type
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<p class="MsoNormal">But those custom preludes would have to be updated anyway, right?<o:p></o:p></p>
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<p class="MsoNormal">Yes, they would.<o:p></o:p></p>
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<p class="MsoNormal">Richard<o:p></o:p></p>
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<p class="MsoNormal">_______________________________________________<br>
ghc-steering-committee mailing list<br>
<a href="mailto:ghc-steering-committee@haskell.org">ghc-steering-committee@haskell.org</a><br>
<a href="https://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-steering-committee">https://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-steering-committee</a><o:p></o:p></p>
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