Cannot resolve type calling doHover while using and*

[rbjorklin]

I have a piece of code that looks like this:

let example () =
  let* promise_1 = my_fun1 ()
  and* promise_2 = my_fun2 () in
  Lwt.return_unit

where calling doHover on promise_2 just returns unit Lwt.t which also happens to be the type of the entire expression.

[rgrinberg]

cc @voodoos as this is likely a merlin issue.