Given the fact that Haskell 98 demands that class constraints in an explicit type are
in a normal form (either a variable, or a type variable applied to a list of types), it struck me
that in the following (not very useful) program ghci yields a type which is not of that form.
class X a where (><) :: a -> a -> Bool
class Y a where (<>) :: a -> a -> Bool _ <> _ = True
instance Y a => X [a] where x >< y = not(head x <> head y)
--f :: Y a => a -> a -> Bool f g h = [g] >< [h]
Now, in ghci :t f yields f :: forall t. (X [t]) => t -> t -> Bool
Hugs does reduce the type of f to the explicit type in comments.
My question is: is there any special reason for this behaviour?
Jur -- http://www.cs.uu.nl/people/jur/progrock.html -- [EMAIL PROTECTED] If e-mail does not work try [EMAIL PROTECTED]
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