Scoped type variables
ashley at semantic.org
Tue Feb 7 16:40:33 EST 2006
Ben Rudiak-Gould wrote:
> Simon PJ thinks that Haskell' should include scoped type variables, and
> I tend to agree. But I'm unhappy with one aspect of the way they're
> implemented in GHC. What I don't like is that given a signature like
> x :: a -> a
> there's no way to tell, looking at it in isolation, whether a is free or
> bound in the type.
I'd quite like to see a flag that switches off implicit "forall"
quantification altogether, or maybe just warned about it (since I use
-Wall -Werror anyway).
id :: forall a. a -> a
const :: forall a b. a -> b -> a
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