Signature help does not work in the presence of type aliases

[ddickstein]

Signature help appears for M.f:

module M : sig
  val f : int -> unit
end = struct
  let f (_ : int) = ()
end

let () = M.f 5

Signature help does not appear for M.f:

type t = int -> unit

module M : sig
  val f : t
end = struct
  let f (_ : int) = ()
end

let () = M.f 5

[voodoos]

Thanks for the report @ddickstein, that's a quite surprising behavior...
I added a test with your reproduction.