I was trying to upgrade to ghc-7.8 the other day, and got this
compilation failure when building ghc-mtl-1.2.1.0 (see the end of the
message).
I'm using the haskell overlay on Gentoo Linux straight out of the box,
no local cabal installations of anything.
Now I was told that other people can compile ghc-mtl with 7.8 just
fine, so there must be something broken in my specific configuration.
What would be an effective way to approach the situation?
In the sources I see that an instance of MonadIO GHC.Ghc does exist. I
don't understand these errors. Are there multiple different MonadIO
classes in different modules?
Thank you and happy hacking.
Now the errors:
Control/Monad/Ghc.hs:42:15:
No instance for (GHC.MonadIO Ghc)
arising from the 'deriving' clause of a data type declaration
Possible fix:
use a standalone 'deriving instance' declaration,
so you can specify the instance context yourself
When deriving the instance for (GHC.ExceptionMonad Ghc)
Control/Monad/Ghc.hs:46:15:
No instance for (MonadIO GHC.Ghc)
arising from the 'deriving' clause of a data type declaration
Possible fix:
use a standalone 'deriving instance' declaration,
so you can specify the instance context yourself
When deriving the instance for (MonadIO Ghc)
Control/Monad/Ghc.hs:49:15:
No instance for (GHC.MonadIO Ghc)
arising from the 'deriving' clause of a data type declaration
Possible fix:
use a standalone 'deriving instance' declaration,
so you can specify the instance context yourself
When deriving the instance for (GHC.GhcMonad Ghc)
--
this is the real i
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