On May 21, 2011, at 8:55 AM, Paolo G. Giarrusso wrote:
Hi all, I have some problem with ScopedTypeVariables, let and so on, at least in GHC 7. My aim is to be able to supply a polymorphic type signature in let bindings. Confusingly, I find no such example in the blog post about local let generalization [1]. I first met this problem when porting some test-code from Kiselyov, when refusing to convert its let- bindings into where-bindings (which, btw, can't be typed into GHCi). I've also added a comment to the bug report, but it's still quite possible that I'm missing something.
You don't need ScopedTypeVariables for this, you can just give type signatures in the let binding: Prelude> let id2 :: t -> t; id2 = \x -> x in (id2 '1', id2 10) ('1',10) -- James