No instance for `Eq (c r w)' when deriving classes for `Trans'

[Byron Cook]

Here is some code that works well in the Hugs 981111 BETA, but not in
GHC-4.00:

data Trans c i r w = Trans [c r w] i [c r w] [c r w]
                   deriving (Eq,Show)


GHC complains:
Trans.hs:1:
    No instance for `Eq (c r w)'
    When deriving classes for `Trans'


Hugs merrily works on the same code:
Trans> Trans [Reg R (Val (5::Word32))] () [] [] == Trans [Reg R (Val (5::Word32))] () 
[] []
True
Trans> 



- Byron