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.
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`. - Oleg On 20.6.2021 17.57, Edward Kmett wrote: > 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. > > 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. > > -Edward > > On Sun, Jun 20, 2021 at 4:45 AM Chris Smith <[email protected] > <mailto:[email protected]>> wrote: > > Yikes, this is going to break nearly everything. Definitely good > to let people know. > > On Sun, Jun 20, 2021 at 7:43 AM Ben Gamari <[email protected] > <mailto:[email protected]>> wrote: > > Harendra Kumar <[email protected] > <mailto:[email protected]>> writes: > > > I see the following errors when compiling with ghc head version: > > > > $ ghc-stage2 --version > > The Glorious Glasgow Haskell Compilation System, version > 9.3.20210608 > > > > $ cabal build --with-compiler ghc-stage2 --allow-newer > > > > Data/Colour/CIE.hs:80:12: error: > > Ambiguous occurrence ‘sum’ > > It could refer to > > either ‘Prelude.sum’, > > imported from ‘Prelude’ at > Data/Colour/CIE.hs:25:8-22 > > (and originally defined in ‘Data.Foldable’) > > or ‘Data.List.sum’, > > imported from ‘Data.List’ at > Data/Colour/CIE.hs:41:1-16 > > (and originally defined in ‘GHC.List’) > > | > > 80 | total = sum $ map fst l > > | ^^^ > > > > Can someone briefly describe this change and what's the > recommended way of > > fixing this? Just hide the Data.List definition? I do not > see this > > mentioned in the release notes of 9.2/9.4 here: > > > https://ghc.gitlab.haskell.org/ghc/doc/users_guide/9.2.1-notes.html > > > Indeed, this is due to the monomorphic Data.List proposal, > which the > CLC decided would accompany the addition of > Data.List.singleton. The > correct fix here is to either qualify the import of > `Data.List` or add > an explicit import list. I'll try to remember to add a note > about this > to the release notes and migration guide. > > > Cheers, > > - Ben > > _______________________________________________ > ghc-devs mailing list > [email protected] <mailto:[email protected]> > http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs > > _______________________________________________ > ghc-devs mailing list > [email protected] <mailto:[email protected]> > http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs > > > _______________________________________________ > ghc-devs mailing list > [email protected] > http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs
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