Hmm, I never knew that. Is that a GHC thing? Is it strictly necessary? Seems like it could be done in the Num instance for Integers, Ints, etc.

On Fri, May 8, 2009 at 11:51 AM, Neil Mitchell <ndmitchell@gmail.com> wrote:
> Err, I'm not seeing the danger of this
> (+) :: forall a. (Num a) => a -> a -> a
> Doesn't this require the two parameters to be the same instance of Num?

I didn't at first, then I remembered:

1 + True
=
fromInteger 1 + True

And if we have Num for Bool, it type checks.

Thanks

Neil