2014-07-04 9:30 GMT+02:00 Tikhon Jelvis <tikhon@jelv.is>:

You probably want the ScopedTypeVariables extension. You'll also have to qualify the relevant variable with an explicit forall:

    forall l. NatToInt l => ...

Then you can use l in your expression and it will be in scope.


Interesting, what it's the semantic which force me to add an explicit forall?