[Haskell-cafe] MonadPlus instance for IO

David Roundy droundy at abridgegame.org
Wed Feb 2 08:17:49 EST 2005

I'm sure I'm doing something stupid, but somehow ghc isn't recognizing the
existance of a MonadPlus instance for IO:

    No instance for (MonadPlus IO)
      arising from use of `mplus' at DarcsIO.lhs:48
    In the definition of `foo':
        foo = (fail "aaack") `mplus` (fail "foobar")

Any idea what I'm doing wrong? I'm using

$ ghc --version
The Glorious Glasgow Haskell Compilation System, version 6.2.2

packaged for debian.
David Roundy

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