> You need to change the first line to this:
>
> > data C a = C { pair :: forall b. b -> (b,a) }
>
> and then it works fine (with -fglasgow-exts). But you've now stepped
> outside the bounds of Haskell 98.
(oops, replying to myself... sure sign of madness! :) )
I hasten to add that this is *not* the same as existential quantification; note
carefully the location of the forall wrt the constructor.
--KW 8-)
--
Keith Wansbrough <[EMAIL PROTECTED]>
http://www.cl.cam.ac.uk/users/kw217/
University of Cambridge Computer Laboratory.
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