ocamllsp not recognizing custom modules

So I'm working on a project in which there is an ast.ml file and a compilateur.ml file, the compilateur.ml uses variables and types from ast.ml so i added the line

open Ast

at the beginning of my compilateur.ml file, but i get an error from ocamllsp: Unbound module Ast

I'm working on the project with someone else who has all the same files, but the error doesn't appear on their vscode, the only difference (or it seems) is the sandbox, mine looks like this:

But in his, >dune appears in the list.

Here are my config infos:

opam version: 2.0.8ocaml version: 4.11.1dune version: 3.16

and here is my dune file:

(ocamllex (modules lexer))(menhir (modules parser))(executable (name compilateur) (promote (until-clean)) (modules lexer parser ast compilateur) (libraries yojson) (flags ()))