On Tue, Oct 1, 2013 at 5:25 PM, Patrick Redmond <plredmond@gmail.com> wrote:
Prelude> :t ((+ 1) / 2)
((+ 1) / 2) :: (Fractional (a -> a), Num a) => a -> a
The key is that typeclasses are open. You could write a Fractional instance for (a -> a), in which case it would be possible to do _something_ with this code. Would it be useful? Even Haskell can't guarantee that.