<div dir="ltr"><div>Just an aside. I looked up the GHC user guide and found this:</div><div><br></div><div>
<dt id="gmail-ghc-flag--Wcompat-unqualified-imports">
<code class="gmail-descname">-<span class="gmail-highlighted">Wcompat</span>-unqualified-imports</code></dt><dd><p>Warns on qualified imports of core library modules which are subject to
change in future GHC releases.</p></dd><dt>I got confused by the text. I guess it was meant to be "Warns on unqualified imports".</dt><dd><br></dd></div><div>-harendra<br></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Sun, 20 Jun 2021 at 20:39, Oleg Grenrus <<a href="mailto:oleg.grenrus@iki.fi">oleg.grenrus@iki.fi</a>> wrote:<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>
What is the reason that -Wcompat flags are not enabled by -Wall? The
unqualified Data.List import was warned by -Wcompat about since
GHC-8.10, I'm surprised that it still surprise people.<br>
<br>
Should -Wcompat be implied by -Wall? Why not? I think that people
who won't ever consider upgrading GHC to be a very very small
minority, and they can suppress these warnings with `-Wall
-Wno-compat`.<br>
<br>
- Oleg<br>
<br>
On 20.6.2021 17.57, Edward Kmett wrote:<br>
<blockquote type="cite">
<div dir="ltr">The breakage concern is why Data.List wound up in
its limbo-like state of re-exporting the Foldable-polymorphic
combinators since 7.10 -- while "weird", it was the only option
that didn't have to choose between removing the names from
Data.List exports entirely and breaking unqualified imports of
Data.List.
<div><br>
</div>
<div>With the monomorphized combinators in place, Data.List
should be considered a 'qualified' import like Data.Map. We
definitely need to do more to communicate that this is
changing and how users should adjust their code to suit. After
all, by far the most common intended import from Data.List is
the humble 'sort', which doesn't conflict.</div>
<div><br>
</div>
<div>-Edward</div>
</div>
<br>
<div class="gmail_quote">
<div dir="ltr" class="gmail_attr">On Sun, Jun 20, 2021 at 4:45
AM Chris Smith <<a href="mailto:cdsmith@gmail.com" target="_blank">cdsmith@gmail.com</a>> wrote:<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">Yikes, this is going to break nearly
everything. Definitely good to let people know.</div>
<br>
<div class="gmail_quote">
<div dir="ltr" class="gmail_attr">On Sun, Jun 20, 2021 at
7:43 AM Ben Gamari <<a href="mailto:ben@smart-cactus.org" target="_blank">ben@smart-cactus.org</a>>
wrote:<br>
</div>
<blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">Harendra Kumar <<a href="mailto:harendra.kumar@gmail.com" target="_blank">harendra.kumar@gmail.com</a>>
writes:<br>
<br>
> I see the following errors when compiling with ghc
head version:<br>
><br>
> $ ghc-stage2 --version<br>
> The Glorious Glasgow Haskell Compilation System,
version 9.3.20210608<br>
><br>
> $ cabal build --with-compiler ghc-stage2
--allow-newer<br>
><br>
> Data/Colour/CIE.hs:80:12: error:<br>
> Ambiguous occurrence ‘sum’<br>
> It could refer to<br>
> either ‘Prelude.sum’,<br>
> imported from ‘Prelude’ at
Data/Colour/CIE.hs:25:8-22<br>
> (and originally defined in
‘Data.Foldable’)<br>
> or ‘Data.List.sum’,<br>
> imported from ‘Data.List’ at
Data/Colour/CIE.hs:41:1-16<br>
> (and originally defined in ‘GHC.List’)<br>
> |<br>
> 80 | total = sum $ map fst l<br>
> | ^^^<br>
><br>
> Can someone briefly describe this change and what's
the recommended way of<br>
> fixing this? Just hide the Data.List definition? I do
not see this<br>
> mentioned in the release notes of 9.2/9.4 here:<br>
> <a href="https://ghc.gitlab.haskell.org/ghc/doc/users_guide/9.2.1-notes.html" rel="noreferrer" target="_blank">https://ghc.gitlab.haskell.org/ghc/doc/users_guide/9.2.1-notes.html</a><br>
><br>
Indeed, this is due to the monomorphic Data.List proposal,
which the<br>
CLC decided would accompany the addition of
Data.List.singleton. The<br>
correct fix here is to either qualify the import of
`Data.List` or add<br>
an explicit import list. I'll try to remember to add a
note about this<br>
to the release notes and migration guide.<br>
<br>
<br>
Cheers,<br>
<br>
- Ben<br>
<br>
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