Consider this code:

let x = false
let f () =
  let open Unknown in
  x
;;

Since x may be present in the unknown module we are attempting to open, we can't really be sure we're talking about the x defined at the top. type-enclosing assumes that we are, and reports bool, but locate does not assume that, and fails with "Not in environment 'x'".

I think that the better behavior is probably to assume we're talking about the x that's available, as type-enclosing does, and that locate should be fixed to jump to x as well. But if that's considered unprincipled, we need a clearer error message than "Not in environment," and it needs to apply consistently across commands.