Re: [Haskell-cafe] A question about functional dependencies and existential quantification

Hi, thanks for your quick answer. Do you have any predictions when System F_c in GHC will be available for usage? Regards, Jean-Marie Simon Peyton-Jones wrote:

What you want to do is perfectly reasonable -- but it cannot be translated into System F and that's why GHC rejects it.

GHC now has a richer intermediate language that *can* handle this; see our paper http://research.microsoft.com/~simonpj/papers/ext-f.

Manuel and Martin and I are now working on the *source*-language aspects, incl type inference. When we are done, we'll be able to compile your program, or at least one very like it.

So, stay tuned. Meanwhile thank you for the example.