diff --git a/src/dune_rules/expander.ml b/src/dune_rules/expander.ml
index 91b6ada9b8f4..10b9472ab0af 100644
--- a/src/dune_rules/expander.ml
+++ b/src/dune_rules/expander.ml
@@ -909,24 +909,6 @@ let expand_and_eval_set t set ~standard =
   Ordered_set_lang.eval set ~standard ~eq:String.equal ~parse:(fun ~loc:_ s -> s)
 ;;
 
-module Unordered (Key : Ordered_set_lang.Key) = struct
-  module Unordered = Ordered_set_lang.Unordered (Key)
-
-  let expand_and_eval t set ~ctx ~parse ~key ~standard =
-    let dir = Path.build (dir t) in
-    let+ set = expand_ordered_set_lang set ~dir ~f:(expand_pform t) in
-    let ctx = ref ctx in
-    let parse ~loc x =
-      let x, ctx' = parse ~loc ~ctx:!ctx x in
-      ctx := ctx';
-      x
-    in
-    let r = Unordered.eval_loc set ~parse ~key ~standard in
-    let ctx = !ctx in
-    r, ctx
-  ;;
-end
-
 let eval_blang t blang =
   Blang_expand.eval ~f:(No_deps.expand_pform t) ~dir:(Path.build t.dir) blang
 ;;
diff --git a/src/dune_rules/expander.mli b/src/dune_rules/expander.mli
index 4d2d3434ed28..befe45951269 100644
--- a/src/dune_rules/expander.mli
+++ b/src/dune_rules/expander.mli
@@ -107,6 +107,12 @@ module With_reduced_var_set : sig
   val eval_blang : context:Context.t -> dir:Path.Build.t -> Blang.t -> bool Memo.t
 end
 
+val expand_ordered_set_lang
+  :  Ordered_set_lang.Unexpanded.t
+  -> dir:Path.t
+  -> f:Value.t list Action_builder.t String_with_vars.expander
+  -> Ordered_set_lang.t Action_builder.t
+
 (** Expand forms of the form (:standard \ foo bar). Expansion is only possible
     inside [Action_builder.t] because such forms may contain the form (:include
     ..) which needs files to be built. *)
@@ -116,17 +122,6 @@ val expand_and_eval_set
   -> standard:string list Action_builder.t
   -> string list Action_builder.t
 
-module Unordered (Key : Ordered_set_lang.Key) : sig
-  val expand_and_eval
-    :  t
-    -> Ordered_set_lang.Unexpanded.t
-    -> ctx:'ctx
-    -> parse:(loc:Loc.t -> ctx:'ctx -> string -> 'a * 'ctx)
-    -> key:('a -> Key.t)
-    -> standard:(Loc.t * 'a) Key.Map.t
-    -> ((Loc.t * 'a) Key.Map.t * 'ctx) Action_builder.t
-end
-
 val eval_blang : t -> Blang.t -> bool Memo.t
 val map_exe : t -> Path.t -> Path.t
 val artifacts : t -> Artifacts.t
diff --git a/src/dune_rules/modules_field_evaluator.ml b/src/dune_rules/modules_field_evaluator.ml
index 5707074434dc..b78a4d2e8e86 100644
--- a/src/dune_rules/modules_field_evaluator.ml
+++ b/src/dune_rules/modules_field_evaluator.ml
@@ -30,14 +30,25 @@ let eval0 =
     module Map = Module_trie
   end
   in
-  let module Unordered = Expander.Unordered (Key) in
+  let module Unordered = Ordered_set_lang.Unordered (Key) in
   (* Fake modules are modules that do not exist but it doesn't matter because
      they are only removed from a set (for jbuild file compatibility) *)
-  let parse ~all_modules ~loc ~ctx:fake_modules s =
+  let expand_and_eval t set ~parse ~key ~standard =
+    let open Action_builder.O in
+    let dir = Path.build (Expander.dir t) in
+    let+ set = Expander.expand_ordered_set_lang set ~dir ~f:(Expander.expand_pform t) in
+    let fake_modules = ref Module_name.Map.empty in
+    let parse ~loc x = parse ~loc ~fake_modules x in
+    let r = Unordered.eval_loc set ~parse ~key ~standard in
+    r, !fake_modules
+  in
+  let parse ~all_modules ~loc ~fake_modules s =
     let name = Module_name.of_string_allow_invalid (loc, s) in
     match Module_trie.find all_modules [ name ] with
-    | Some m -> Ok m, fake_modules
-    | None -> Error name, Module_name.Map.set fake_modules name loc
+    | Some m -> Ok m
+    | None ->
+      fake_modules := Module_name.Map.set !fake_modules name loc;
+      Error name
   in
   fun ~expander ~loc ~all_modules ~standard osl ->
     let open Memo.O in
@@ -45,13 +56,7 @@ let eval0 =
     let standard = Module_trie.map standard ~f:(fun m -> loc, Ok m) in
     let+ (modules, fake_modules), _ =
       Action_builder.evaluate_and_collect_facts
-        (Unordered.expand_and_eval
-           expander
-           ~ctx:Module_name.Map.empty
-           ~parse
-           ~standard
-           ~key
-           osl)
+        (expand_and_eval expander ~parse ~standard ~key osl)
     in
     let modules =
       Module_trie.filter_map modules ~f:(fun (loc, m) ->