dreaded non-modular instances; ghci bug, Either, and haddock

[Simon Peyton-Jones]

| Duplicate instance declarations:
|   ../tools/base/lib/Monads/ExceptM.hs:26: Functor (Either x)
|   <No locn>: Functor (Either e)

Yes, this is bad.  The HEAD reports the module which defined the
instance:

Inst.hs:3:
    Duplicate instance declarations:
      Inst.hs:3: Eq [a]
      In module GHC.Base: Eq [a]

I don't think this has made it into the 5.04 branch, though.


| ghci doesn't seem to clean up instances when switching between
modules?

Yes, I think that is right too.  It should.

Simon