Jeff Polakow wrote:
Hello,
I filed the following bug report:
This produces a type error:
foo :: forall b. (b -> String, Int)
foo = (const "hi", 0)
bar :: (forall b. b -> String, Int)
bar = foo
But the types are equivalent.
Once you cross the forall the type of b becomes fixed.
case foo of
(f,i) -> {- Here f is monomorphic :: b -> String -}
case bar of
(f,i) -> {- Here f is still polymorphic :: forall b. b -> String -}
Think of how you would seal these with a newtype:
newtype Foo = forall a. Foo (a -> String, Int)
newtype F = forall a. F (a -> String)
type Bar = (F,Int)
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