transformers and GHC

Hi Ross and other GHC folk,

Currently, we build transformers in a GHC tree, but we don't ship and
install it. However, the ghc library redefines

    class Monad m => MonadIO m where
        liftIO :: IO a -> m a

which seems a little silly, and means that a client of both the GHC API
and other libraries may need to use 2 different MonadIO/liftIO's.

So I propose we start shipping transformers with GHC, and get rid of
GHC's MonadIO class. The main argument against shipping libraries with
GHC in general is that it effectively means end users don't get new
releases of the library until there is a new GHC release out, but
transformers is so stable (notwithstanding the current libraries@
proposal) that I don't think that's much of an issue in this case.

What do you think?


Thanks
Ian