merlin-locate does not work on +.

[Chris00]

merlin-locate does not work when the point in on a dotted infix operator such as +. (in Emacs).

Example:

module A = struct
  let ( +. ) a b = a +. b
end

let f x = A.(x +. 1.)

(put the cursor on the latest +. and M-x merlin-locate).

[trefis]

The answer I get when I try it is Not in environment ''.

Note for whoever tries to fix this: looks like a bug in reconstruct_identifier.

[rgrinberg]

I had a brief look, and I think it might be a bug in Longident.parse instead. Longident.parse "+." does not seem to work as expected.

cc @gasche

[gasche]

(I gave some context in ocaml-ppx/ppxlib#111 (comment).)

For the needs of Merlin, the choice of exposing the more robust functions from the parser seems reasonable. Should we experiment with a PR to do this in trunk?

[Octachron]

Should I add a generic Longident.t parser to ocaml/ocaml#9021?