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<p class="msipheader7557e74b" style="margin:0in"><span style="font-size:9.0pt;font-family:"Arial",sans-serif;color:#317100">PUBLIC</span><o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial",sans-serif;mso-fareast-language:EN-US">OK, I must be doing something wrong then. I am now looking at Tidy (not Prep) output, and I see Core like this:<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial",sans-serif;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-family:"Lucida Console"">
<span style="color:black;background:silver;mso-highlight:silver">showsPrec ::</span> forall a. Show a => Int -> a -> ShowS<o:p></o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-family:"Lucida Console""> [GblId[ClassOp],<o:p></o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-family:"Lucida Console""> Arity=1,<o:p></o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-family:"Lucida Console""> Caf=NoCafRefs,<o:p></o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-family:"Lucida Console""> Str=<S!P(SL,A,A)>,<o:p></o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-family:"Lucida Console""> RULES: Built in rule for showsPrec: "Class op showsPrec"]<o:p></o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-family:"Lucida Console""> showsPrec<o:p></o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-family:"Lucida Console""> = \ (@a_a1G3) (v_B1 :: Show a_a1G3) -><o:p></o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-family:"Lucida Console""> case v_B1 of v_B1 { C:Show v_B2 v_B3 v_B4 -> v_B2 }<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial",sans-serif;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial",sans-serif;mso-fareast-language:EN-US">so if I’m reading this right, these
</span><span style="font-family:"Lucida Console";mso-fareast-language:EN-US">v</span><span style="font-size:10.0pt;font-family:"Arial",sans-serif;mso-fareast-language:EN-US">s are still shadowing.
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial",sans-serif;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial",sans-serif;mso-fareast-language:EN-US">I am using
</span><span style="font-family:"Lucida Console";mso-fareast-language:EN-US">tidyProgram</span><span style="font-size:10.0pt;font-family:"Arial",sans-serif;mso-fareast-language:EN-US"> on the output of
</span><span style="font-family:"Lucida Console";mso-fareast-language:EN-US">hscSimplify</span><span style="font-size:10.0pt;font-family:"Arial",sans-serif;mso-fareast-language:EN-US">, and then taking the
</span><span style="font-family:"Lucida Console";mso-fareast-language:EN-US">cg_binds</span><span style="font-size:10.0pt;font-family:"Arial",sans-serif;mso-fareast-language:EN-US"> of its result. What else should I do to get tidy (heh) Tidy output?<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial",sans-serif;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial",sans-serif;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<div>
<div style="border:none;border-top:solid #E1E1E1 1.0pt;padding:3.0pt 0in 0in 0in">
<p class="MsoNormal"><b><span lang="EN-US">From:</span></b><span lang="EN-US"> ghc-devs <ghc-devs-bounces@haskell.org>
<b>On Behalf Of </b>Simon Peyton Jones<br>
<b>Sent:</b> Monday, April 4, 2022 4:28 PM<br>
<b>To:</b> Gergõ Érdi <gergo@erdi.hu><br>
<b>Cc:</b> GHC Devs <ghc-devs@haskell.org><br>
<b>Subject:</b> [External] Re: Shadowing in toIface* output<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><span style="font-family:"Tahoma",sans-serif">So does that mean Tidy produces unique `occNameFS`s, and then `Prep`<br>
breaks them? <o:p></o:p></span></p>
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<div style="margin-left:30.0pt">
<p class="MsoNormal"><span style="font-family:"Tahoma",sans-serif"><o:p> </o:p></span></p>
</div>
<div>
<p class="MsoNormal"><span style="font-family:"Tahoma",sans-serif">Tidy does not produce unique OccNames. Rather, it avoids
<i>shadowing</i>, so that if you delete all the uniques and print out the program (which is precisely what happens in an .hi file) you'll still get something sensible.<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Tahoma",sans-serif"><o:p> </o:p></span></p>
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<div>
<p class="MsoNormal"><span style="font-family:"Tahoma",sans-serif">I'm not sure whether or not Prep maintains this invariant. There is no particular reason it should. It might, but it is not (currently) a goal.<o:p></o:p></span></p>
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<div>
<p class="MsoNormal"><span style="font-family:"Tahoma",sans-serif"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Tahoma",sans-serif">Simon<o:p></o:p></span></p>
</div>
</div>
<p class="MsoNormal"><o:p> </o:p></p>
<div>
<div>
<p class="MsoNormal">On Sat, 2 Apr 2022 at 04:35, Gergõ Érdi <<a href="mailto:gergo@erdi.hu">gergo@erdi.hu</a>> wrote:<o:p></o:p></p>
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<blockquote style="border:none;border-left:solid #CCCCCC 1.0pt;padding:0in 0in 0in 6.0pt;margin-left:4.8pt;margin-top:5.0pt;margin-right:0in;margin-bottom:5.0pt">
<p class="MsoNormal">So does that mean Tidy produces unique `occNameFS`s, and then `Prep`<br>
breaks them?<br>
<br>
On Fri, Apr 1, 2022 at 10:35 PM Josh Meredith<br>
<<a href="mailto:joshmeredith2008@gmail.com" target="_blank">joshmeredith2008@gmail.com</a>> wrote:<br>
><br>
> Hi,<br>
><br>
> I encountered this when we used that for Plutus. I'll have to dig up the details, but IIRC `toIfaceExpr` expects GHC to have already tidied the output, which deals with this issue of overlapping variable names.<br>
><br>
> Cheers,<br>
> Josh<br>
><br>
> On Sat, 2 Apr 2022 at 01:26, ÉRDI Gergõ <<a href="mailto:gergo@erdi.hu" target="_blank">gergo@erdi.hu</a>> wrote:<br>
>><br>
>> Hi,<br>
>><br>
>> I'm trying to save (Prep'd) Core bindings right next to the serialized<br>
>> `ModIface` (so basically `put_`ing them into the same bytestream, after the<br>
>> `ModIface`), and that's exactly what the functions in `GHC.CoreToIface`<br>
>> seem to be for, so I expected it to Just Work. However, I noticed that I<br>
>> very frequently get problems with shadowing. For example, Core that looks<br>
>> like `\v{u1} v{u2} -> v{u1}` would get translated to `\v v -> v`, which is<br>
>> disastrous since these locally bound `Var`s are represented as just their<br>
>> `getOccFS` (i.e. the `FastString` `"v"`).<br>
>><br>
>> But this can't be right: if `toIfaceExpr` &c. would fail this blatently,<br>
>> then the unfoldings couldn't be saved & restored, which is something GHC<br>
>> itself does as part of normal `.hi` file handling. So clearly I must be<br>
>> doing something wrong.<br>
>><br>
>> So I guess my question could be, what could be causing `toIfaceExpr` (a<br>
>> pure function!) to behave this way for my Cores? But then, if I look at<br>
>> the implementation of `toIface*`, I can see that it really doesn't do<br>
>> anything smarter than just storing `getOccFS` in the interface (no<br>
>> uniques in sight)-- so maybe my *real* question is, what is GHC itself<br>
>> doing so that it doesn't have this same problem?<br>
>><br>
>> Thanks,<br>
>> Gergo<br>
>> _______________________________________________<br>
>> ghc-devs mailing list<br>
>> <a href="mailto:ghc-devs@haskell.org" target="_blank">ghc-devs@haskell.org</a><br>
>> <a href="https://clicktime.symantec.com/3BestP7qr2g6Y7xBfCxdDwr6xU?u=http%3A%2F%2Fmail.haskell.org%2Fcgi-bin%2Fmailman%2Flistinfo%2Fghc-devs" target="_blank">
http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs</a><br>
><br>
> _______________________________________________<br>
> ghc-devs mailing list<br>
> <a href="mailto:ghc-devs@haskell.org" target="_blank">ghc-devs@haskell.org</a><br>
> <a href="https://clicktime.symantec.com/3BestP7qr2g6Y7xBfCxdDwr6xU?u=http%3A%2F%2Fmail.haskell.org%2Fcgi-bin%2Fmailman%2Flistinfo%2Fghc-devs" target="_blank">
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