Thats what I get for writing it inline rather than pasting =)

On Sat, Nov 12, 2011 at 3:41 PM, Erik Hesselink <hesselink@gmail.com> wrote:

On Sat, Nov 12, 2011 at 21:29, Edward Kmett <ekmett@gmail.com> wrote:
> instance Monoid e => Monad ((,) e) where
> return a = (a, mempty)

This should probably be:
return a = (mempty, a)

Erik