fix: read the processed file in Ocamldep.read_immediate_deps_of

Signed-off-by: Antonio Nuno Monteiro <anmonteiro@gmail.com>

src/dune_rules/ocamldep.ml

@@ -153,13 +153,16 @@ let read_deps_of ~obj_dir ~modules ~ml_kind unit =
 ;;
 
 let read_immediate_deps_of ~obj_dir ~modules ~ml_kind unit =
-  match Module.source ~ml_kind unit with
+  match
+    let ml = Module.ml_source unit in
+    Module.file ml ~ml_kind
+  with
   | None -> Action_builder.return []
-  | Some source ->
+  | Some file ->
     let ocamldep_output = Obj_dir.Module.dep obj_dir (Immediate (unit, ml_kind)) in
     Action_builder.lines_of (Path.build ocamldep_output)
     |> Action_builder.map ~f:(fun lines ->
-      parse_deps_exn ~file:(Module.File.path source) lines
+      parse_deps_exn ~file lines
       |> parse_module_names ~dir:(Obj_dir.dir obj_dir) ~unit ~modules)
     |> Action_builder.memoize (Path.Build.to_string ocamldep_output)
 ;;

test/blackbox-tests/test-cases/melange/unexpected-ocamldep-output.t

@@ -30,9 +30,4 @@ file after any dialects have run
   > let name = "Zoe"
   > EOF
   $ dune build @mel
-  Error: ocamldep returned unexpected output for _build/default/lib/foo.myd:
-  > lib/foo.myd.ml: Bar
-  -> required by _build/default/output/lib/foo.js
-  -> required by alias mel
-  [1]