Yes, this is a common hazard when trying to use cabal-install with GHC HEAD. My recommendation is to use the Cabal tip distributed with GHC HEAD.
Edward Excerpts from Oleg Grenrus's message of 2015-08-26 12:29:16 -0700: > Ah, so this happens because GHC HEAD has Cabal-1.23.0.0 bundled with it. I > see. > And as Cabal master is also 1.23.0.0 they don’t really work together (i.e. > cabal-install uses system Cabal). > > Ok, maybe we can wait till GHC’s Cabal reference-commit will be bumped, if > not already. > > Thanks for the explanation. > > - Oleg > > > On 19 Aug 2015, at 19:19, Edward Z. Yang <[email protected]> wrote: > > > > Oh, this is irritating. > > > > The problem is we recently updated Cabal the library to get rid of > > InstalledPackageInfo_ (so there is only InstalledPackageInfo now) > > but it looks like in some situations cabal-install can be compiled > > with an old version of Cabal (as is happening to you). I suppose > > an appropriate remedy is to bump the Cabal library dependency in > > cabal-install so we don't attempt to use the old Cabal; alternately > > we could preprocessor macro to make it work in both cases. > > > > Edward > > > > Excerpts from Oleg Grenrus's message of 2015-08-19 07:46:56 -0700: > >> I tried to fix compilation of Cabal using Cabal HEAD. It’s trivial patch: > >> > >> https://github.com/phadej/cabal/commit/525e0680505c74f42a321e55b357a27222790628 > >> > >> but it breaks build on every other released GHC: > >> > >> https://travis-ci.org/phadej/cabal/builds/76288656 > >> > >> — > >> > >> The original issue GHC-7.11 complained was: > >> > >> Distribution/Client/Types.hs:71:10: error: > >> Illegal instance declaration for > >> ‘PackageFixedDeps InstalledPackageInfo’ > >> (All instance types must be of the form (T t1 ... tn) > >> where T is not a synonym. > >> Use TypeSynonymInstances if you want to disable this.) > >> In the instance declaration for > >> ‘PackageFixedDeps InstalledPackageInfo’ > >> > >> So I had to add TypeSynonymInstances and FlexibleInstances > >> > >> And also had to change import of InstalledPackageInfo(exposed) in Haddock > >> module. > >> > >> — > >> > >> At this point I’m really confused. I cannot find ‘InstalledPackageInfo_’ > >> symbol anywhere. Can someone explain what happens? > > _______________________________________________ ghc-devs mailing list [email protected] http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs
