Typing problem when generating gathered event-mapped signals

[remyzorg]

The scope of the type variables is weird, see this example :

let make v1 v2 = v1, v2 in
let a =
  let (x, y) : ('a * ('a -> 'b -> 'a)) =
    ("", fun acc x -> acc ^ x)
  in make x y
in
let b =
  let (x, y) : ('a * ('a -> 'b -> 'a)) =
    ([], fun acc x -> x :: acc)
  in make x y 
in a, b

see eb9da6d

[remyzorg]

68f6d9b leaves the same problem when adding constraints to the expression inside let