[Haskell-cafe] Re: Typeclass question

[Benjamin Franksen]

Stefan O'Rear wrote:
> [...]
> Unfortunately, it turns out that
> allowing foralls inside function arguments makes typechecking much
> harder, in general impossible.

Just a tiny correction: AFAIK, it is type /inference/ which becomes
undecidable in the presence of higher rank types -- checking works just
fine (it could be true that it's harder, though).

Cheers
Ben