Outcome printer: ambiguous printing of the types of curried functions and uncurried higher-order functions

[glennsl]

module M: {
  let f: string => int => float
} = {
  let f = f => f("")->float
}

The above fails to compile with the non-sensical error:

  Signature mismatch:
  ...
  Values do not match:
    let f: string => int => float
  is not included in
    let f: string => int => float

While the following does compile:

module M: {
  let f: string => int => float
} = {
  let f = _s => n => n->float
}

(PS: Adding parens to the first example makes it compile of course, this is just to reproduce the error message. The issue is solely with the printer.)