[Haskell-cafe] Declaring variance of class parameters?

Jacques Carette carette at mcmaster.ca
Tue Feb 27 14:00:29 EST 2007

If I have a class, say
class Symantics repr where
  int:: Int -> repr Int

and so on, I would like to *require* that 'repr' be covariant.  Is there 
any way to do that?


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