Solved: Typing problems with polymorphic recursion and typeclasses

Keith Wansbrough Keith.Wansbrough@cl.cam.ac.uk
Fri, 02 May 2003 10:23:41 +0100


Oleg writes:

> the real type of h is 
>     forall t. t -> (function-of-t)
> 
> The real type of h is not totally polymorphic : it is dependent!

Ummm... that doesn't look like a dependent type to me, it looks like a
functional dependency.  A dependent type would be

  forall t. x::t -> (function-of-x)

Perhaps it's not (quite) so surprising?

--KW 8-)