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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;mso-fareast-language:EN-US">I don’t believe I made this commit, or the ones around it. Mysterious; I hope I’m not being impersonated!<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;mso-fareast-language:EN-US">Simon<o:p></o:p></span></p>
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<p class="MsoNormal"><b><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif">From:</span></b><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif"> noreply@phabricator.haskell.org [mailto:noreply@phabricator.haskell.org]
<br>
<b>Sent:</b> 08 July 2016 20:43<br>
<b>To:</b> Simon Peyton Jones <simonpj@microsoft.com><br>
<b>Subject:</b> [Diffusion] [Committed] rCABAL2863a628f857: Add two local type signatures<o:p></o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">simonpj committed rCABAL2863a628f857: Add two local type signatures (authored by simonpj).
<o:p></o:p></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Calibri",sans-serif"><o:p> </o:p></span></p>
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<p>Add two local type signatures<o:p></o:p></p>
<p>I'm adding these type signatures to satisfy the "do not generalise<br>
local let/where" rule that GHC is taking on.<o:p></o:p></p>
<p>The signatures are clearly correct, but I was surprised at the <br>
polymorphism needed. For example<o:p></o:p></p>
<p>parseOptVersion :: ReadP r Version<br>
parseOptVersion = parseQuoted ver <++ ver<o:p></o:p></p>
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<pre style="line-height:11.25pt"><span style="font-size:8.5pt;font-family:Consolas">where ver :: ReadP r Version<o:p></o:p></span></pre>
<pre style="line-height:11.25pt"><span style="font-size:8.5pt;font-family:Consolas"> ver = parse <++ return noVersion<o:p></o:p></span></pre>
<pre style="line-height:11.25pt"><span style="font-size:8.5pt;font-family:Consolas"> noVersion = Version{ versionBranch=[], versionTags=[] }<o:p></o:p></span></pre>
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<p>Note that 'ver' really is called at two different types! That <br>
in turn is because of the type of (<++)<o:p></o:p></p>
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<pre style="line-height:11.25pt"><span style="font-size:8.5pt;font-family:Consolas">(<++) :: ReadP a a -> ReadP r a -> ReadP r a<o:p></o:p></span></pre>
<pre style="line-height:11.25pt"><span style="font-size:8.5pt;font-family:Consolas">(+++) :: ReadP r a -> ReadP r a -> ReadP r a<o:p></o:p></span></pre>
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<p>Note the "a a" in the first arg, which is very unusual.<br>
For example, compare the type of (+++).<o:p></o:p></p>
<p>Changing it to match the type of (+++) makes ReadP fail to compile,<br>
though, so I assume it's right as it stands. But surely this deserves<br>
a comment?!<o:p></o:p></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Calibri",sans-serif"><o:p> </o:p></span></p>
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<p class="MsoNormal"><strong><span style="font-size:10.0pt;font-family:"Calibri",sans-serif">AFFECTED FILES</span></strong><span style="font-size:10.0pt;font-family:"Calibri",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Calibri",sans-serif">/Distribution/ParseUtils.hs<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Calibri",sans-serif"><o:p> </o:p></span></p>
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<p class="MsoNormal"><strong><span style="font-size:10.0pt;font-family:"Calibri",sans-serif">USERS</span></strong><span style="font-size:10.0pt;font-family:"Calibri",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Calibri",sans-serif">simonpj (Author)<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Calibri",sans-serif"><o:p> </o:p></span></p>
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<p class="MsoNormal"><strong><span style="font-size:10.0pt;font-family:"Calibri",sans-serif">COMMIT</span></strong><span style="font-size:10.0pt;font-family:"Calibri",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Calibri",sans-serif"><a href="https://phabricator.haskell.org/rCABAL2863a628f857">https://phabricator.haskell.org/rCABAL2863a628f857</a><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Calibri",sans-serif"><o:p> </o:p></span></p>
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<p class="MsoNormal"><strong><span style="font-size:10.0pt;font-family:"Calibri",sans-serif">EMAIL PREFERENCES</span></strong><span style="font-size:10.0pt;font-family:"Calibri",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Calibri",sans-serif"><a href="https://phabricator.haskell.org/settings/panel/emailpreferences/">https://phabricator.haskell.org/settings/panel/emailpreferences/</a><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Calibri",sans-serif"><o:p> </o:p></span></p>
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<p class="MsoNormal"><strong><span style="font-size:10.0pt;font-family:"Calibri",sans-serif">To:
</span></strong><span style="font-size:10.0pt;font-family:"Calibri",sans-serif">simonpj<o:p></o:p></span></p>
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