basicTypes/Var.lhs:194: Non-exhaustive patterns in function readMutTyVar

[Thomas Hallgren]

Hi,

Here is another example which GHC doesn't like.

Regards,
Thomas Hallgren
 
------------------------------------------------------------------------

module PR where

-- This accepted by Hugs, but not by GHC 4.08.1

class P a
class R a b | b->a

instance (P a,R a b) => P b

{-
GHC 4.08.1 doesn't seem to allow variables in the context that don't appear
after the =>, but which are still ok since they are determined by the
functional dependenices.
-}