diff --git a/lib/Ast.ml b/lib/Ast.ml
index 07ea090f4a..b6eabe098a 100644
--- a/lib/Ast.ml
+++ b/lib/Ast.ml
@@ -1585,7 +1585,7 @@ end = struct
          |Pexp_unboxed_field (e, _)
          |Pexp_lazy e
          |Pexp_letexception (_, e)
-         |Pexp_letmodule (_, _, _, e)
+         |Pexp_letmodule (_, _, _, _, e)
          |Pexp_newtype (_, e)
          |Pexp_open (_, e)
          |Pexp_letopen (_, e)
@@ -2291,7 +2291,7 @@ end = struct
         | Pexp_let (_, e)
          |Pexp_letop {body= e; _}
          |Pexp_letexception (_, e)
-         |Pexp_letmodule (_, _, _, e) -> (
+         |Pexp_letmodule (_, _, _, _, e) -> (
           match cls with Match | Then | ThenElse -> continue e | _ -> false )
         | Pexp_match _ when match cls with Then -> true | _ -> false ->
             false
@@ -2370,7 +2370,7 @@ end = struct
       | Pexp_let (_, e)
        |Pexp_letop {body= e; _}
        |Pexp_letexception (_, e)
-       |Pexp_letmodule (_, _, _, e) ->
+       |Pexp_letmodule (_, _, _, _, e) ->
           continue e
       | Pexp_ifthenelse (eN, None) -> continue (List.last_exn eN).if_body
       | Pexp_extension (ext, PStr [{pstr_desc= Pstr_eval (e, _); _}])
@@ -2461,7 +2461,7 @@ end = struct
       | Exp {pexp_desc; _} -> (
         match pexp_desc with
         | Pexp_let (_, e)
-         |Pexp_letmodule (_, _, _, e)
+         |Pexp_letmodule (_, _, _, _, e)
          |Pexp_letexception (_, e)
          |Pexp_letopen (_, e)
          |Pexp_open (_, e)
diff --git a/lib/Exposed.ml b/lib/Exposed.ml
index 71902b5e25..5bd04d0de7 100644
--- a/lib/Exposed.ml
+++ b/lib/Exposed.ml
@@ -176,7 +176,7 @@ module Right_square = struct
       | Pexp_ifthenelse (_, Some exp) -> expression exp
       | Pexp_sequence (_, exp) -> expression exp
       | Pexp_setinstvar (_, exp) -> expression exp
-      | Pexp_letmodule (_, _, _, exp) -> expression exp
+      | Pexp_letmodule (_, _, _, _, exp) -> expression exp
       | Pexp_letexception (_, exp) -> expression exp
       | Pexp_assert exp -> expression exp
       | Pexp_lazy exp -> expression exp
diff --git a/lib/Fmt_ast.ml b/lib/Fmt_ast.ml
index f322de7f69..9eab1536e4 100644
--- a/lib/Fmt_ast.ml
+++ b/lib/Fmt_ast.ml
@@ -640,6 +640,28 @@ let let_binding_can_be_punned ~binding ~is_ext =
       true
   | _ -> false
 
+let extract_module_binding_constraints c ctx modes body =
+  let xbody = sub_mod ~ctx body in
+  let xbody, xmty, xmodes =
+    match xbody.ast with
+    | { pmod_desc= Pmod_constraint (body_me, body_mt, body_mm)
+      ; pmod_loc
+      ; pmod_attributes= [] } ->
+        let xbody = sub_mod ~ctx body_me in
+        let xmty, after =
+          match body_mt with
+          | None -> (None, body_me.pmod_loc)
+          | Some body_mt -> (Some (sub_mty ~ctx body_mt), body_mt.pmty_loc)
+        in
+        Cmts.relocate c.cmts ~src:pmod_loc ~before:body_me.pmod_loc ~after ;
+        (xbody, xmty, body_mm)
+    | _ -> (xbody, None, [])
+  in
+  (* [xmodes_id] is the modes on the identifier, while [xmodes] is the modes
+     on the RHS. For example, [module (F @ xmodes_id) () @ xmodes = ...]. *)
+  let xmodes_id = modes in
+  (xmodes_id, xmty, xmodes, xbody)
+
 let rec fmt_extension_aux c ctx ~key (ext, pld) =
   match (ext.txt, pld, ctx) with
   (* Quoted extensions (since ocaml 4.11). *)
@@ -2839,25 +2861,10 @@ and fmt_expression c ?(box = true) ?(pro = noop) ?eol ?parens
               $ fmt "@;<1000 0>"
               $ fmt_expression c (sub_exp ~ctx exp) )
           $ fmt_atrs )
-  | Pexp_letmodule (name, args, pmod, exp) ->
+  | Pexp_letmodule (name, modes, args, pmod, exp) ->
       let keyword = "let module" in
-      let xbody = sub_mod ~ctx pmod in
-      let xbody, xmty, xmmodes =
-        match xbody.ast with
-        | { pmod_desc= Pmod_constraint (body_me, body_mt, body_mm)
-          ; pmod_loc
-          ; pmod_attributes= [] } ->
-            let xbody = sub_mod ~ctx body_me in
-            let xmty, after =
-              match body_mt with
-              | None -> (None, body_me.pmod_loc)
-              | Some body_mt ->
-                  (Some (sub_mty ~ctx body_mt), body_mt.pmty_loc)
-            in
-            Cmts.relocate c.cmts ~src:pmod_loc ~before:body_me.pmod_loc
-              ~after ;
-            (xbody, xmty, body_mm)
-        | _ -> (xbody, None, [])
+      let xmodes_id, xmty, xmodes, xbody =
+        extract_module_binding_constraints c ctx modes pmod
       in
       let can_sparse =
         match xbody.ast.pmod_desc with
@@ -2870,8 +2877,8 @@ and fmt_expression c ?(box = true) ?(pro = noop) ?eol ?parens
               (parens || not (List.is_empty pexp_attributes))
               c.conf
               ( hvbox 2
-                  (fmt_module c ctx keyword ~eqty:":" name (Modes xmmodes)
-                     args (Some xbody) xmty
+                  (fmt_module c ctx keyword ~eqty:":" name (Modes xmodes_id)
+                     args (Some xbody) xmty (Modes xmodes)
                      ~attrs:(Ast_helper.Attr.ext_attrs ?ext ())
                      ~epi:(str "in") ~can_sparse ~rec_flag:false )
               $ fmt "@;<1000 0>"
@@ -4569,7 +4576,7 @@ and fmt_class_exprs ?ext c ctx cls =
            @@ Cmts.fmt c cl.pci_loc (doc_before $ class_exprs $ doc_after) )
 
 and fmt_module c ctx ?rec_ ?epi ?(can_sparse = false) keyword ?(eqty = "=")
-    name modals xargs xbody xmty ~attrs ~rec_flag =
+    name modals_id xargs xbody xmty modals ~attrs ~rec_flag =
   let ext = attrs.attrs_extension in
   let blk_t =
     Option.value_map xmty ~default:empty ~f:(fun xmty ->
@@ -4579,20 +4586,11 @@ and fmt_module c ctx ?rec_ ?epi ?(can_sparse = false) keyword ?(eqty = "=")
             Some (str " " $ str eqty $ opt blk.pro (fun pro -> str " " $ pro))
         ; psp= fmt_if (Option.is_none blk.pro) "@;<1 2>" $ blk.psp } )
   in
-  let fmt_name, fmt_trailing_modals =
-    match modals with
-    | Modes _ ->
-        (* [module M : S @ m = M] *)
-        (fmt_str_loc_opt c name, fmt_modals c modals)
-    | Modalities _ ->
-        (* [module (M @@ m) : S] *)
-        ( wrap_if
-            (not (is_empty_modals modals))
-            "(" ")"
-            (fmt_str_loc_opt c name $ fmt_modals c modals)
-        , noop )
-    | No_modals -> (fmt_str_loc_opt c name, noop)
-    | Mode_crossing _ -> assert false
+  let fmt_name =
+    wrap_if
+      (not (is_empty_modals modals_id))
+      "(" ")"
+      (fmt_str_loc_opt c name $ fmt_modals c modals_id)
   in
   let blk_b = Option.value_map xbody ~default:empty ~f:(fmt_module_expr c) in
   let fmt_name_and_mt ~pro ~loc name mt =
@@ -4656,7 +4654,7 @@ and fmt_module c ctx ?rec_ ?epi ?(can_sparse = false) keyword ?(eqty = "=")
                 ( hvbox args_p.indent
                     (fmt_args ~pro:intro xargs $ fmt_opt blk_t.pro)
                 $ blk_t.psp $ blk_t.bdy )
-            $ blk_t.esp $ fmt_opt blk_t.epi $ fmt_trailing_modals
+            $ blk_t.esp $ fmt_opt blk_t.epi $ fmt_modals c modals
             $ fmt_if (Option.is_some xbody) " ="
             $ fmt_if_k compact fmt_pro )
         $ fmt_if_k (not compact) fmt_pro
@@ -4697,7 +4695,7 @@ and fmt_module_declaration c ~rec_flag ~first {ast= pmd; _} =
   in
   Cmts.fmt c pmd_loc
     (fmt_module ~rec_:rec_flag c ctx keyword pmd_name
-       (Modalities pmd_modalities) pmd_args None ?eqty (Some xmty)
+       (Modalities pmd_modalities) pmd_args None ?eqty (Some xmty) No_modals
        ~rec_flag:(rec_flag && first) ~attrs )
 
 and fmt_module_substitution c ctx pms =
@@ -4714,7 +4712,7 @@ and fmt_module_substitution c ctx pms =
   let pms_name = {pms_name with txt= Some pms_name.txt} in
   Cmts.fmt c pms_loc
     (fmt_module c ctx "module" ~eqty:":=" pms_name No_modals [] None
-       (Some xmty) ~attrs ~rec_flag:false )
+       (Some xmty) No_modals ~attrs ~rec_flag:false )
 
 and fmt_module_type_declaration ?eqty c ctx pmtd =
   let {pmtd_name; pmtd_type; pmtd_ext_attrs= attrs; pmtd_loc} = pmtd in
@@ -4724,7 +4722,7 @@ and fmt_module_type_declaration ?eqty c ctx pmtd =
   fmt_module ?eqty c ctx "module type" pmtd_name No_modals [] None
     ~rec_flag:false
     (Option.map pmtd_type ~f:(sub_mty ~ctx))
-    ~attrs
+    No_modals ~attrs
 
 and fmt_open_description ?ext c ?(keyword = "open") ~kw_attributes
     {popen_expr= popen_lid; popen_override; popen_attributes; popen_loc} =
@@ -4787,14 +4785,14 @@ and fmt_with_constraint c ctx ~pre = function
       let m2 = Some (sub_mty ~ctx m2) in
       str pre $ break 1 2
       $ fmt_module c ctx "module type" m1 No_modals [] None ~rec_flag:false
-          m2
+          m2 No_modals
           ~attrs:(Ast_helper.Attr.ext_attrs ())
   | Pwith_modtypesubst (m1, m2) ->
       let m1 = {m1 with txt= Some (str_longident m1.txt)} in
       let m2 = Some (sub_mty ~ctx m2) in
       str pre $ break 1 2
       $ fmt_module c ctx ~eqty:":=" "module type" m1 No_modals [] None
-          ~rec_flag:false m2
+          ~rec_flag:false m2 No_modals
           ~attrs:(Ast_helper.Attr.ext_attrs ())
 
 and fmt_mod_apply c ctx loc attrs ~parens ~dock_struct me_f arg =
@@ -5361,26 +5359,13 @@ and fmt_module_binding c ~rec_flag ~first {ast= pmb; _} =
   @@ fun c ->
   let ctx = Mb pmb in
   let keyword = if first then "module" else "and" in
-  let xbody = sub_mod ~ctx pmb.pmb_expr in
-  let xbody, xmty, xmodes =
-    match xbody.ast with
-    | { pmod_desc= Pmod_constraint (body_me, body_mt, body_mm)
-      ; pmod_loc
-      ; pmod_attributes= [] } ->
-        let xbody = sub_mod ~ctx body_me in
-        let xmty, after =
-          match body_mt with
-          | None -> (None, body_me.pmod_loc)
-          | Some body_mt -> (Some (sub_mty ~ctx body_mt), body_mt.pmty_loc)
-        in
-        Cmts.relocate c.cmts ~src:pmod_loc ~before:body_me.pmod_loc ~after ;
-        (xbody, xmty, body_mm)
-    | _ -> (xbody, None, [])
+  let xmodes_id, xmty, xmodes, xbody =
+    extract_module_binding_constraints c ctx pmb.pmb_modes pmb.pmb_expr
   in
   Cmts.fmt c pmb.pmb_loc
     (fmt_module ~rec_:rec_flag c ctx keyword ~rec_flag:(rec_flag && first)
-       ~eqty:":" pmb_name (Modes xmodes) pmb.pmb_args (Some xbody) xmty
-       ~attrs )
+       ~eqty:":" pmb_name (Modes xmodes_id) pmb.pmb_args (Some xbody) xmty
+       (Modes xmodes) ~attrs )
 
 let fmt_toplevel_directive c ~semisemi dir =
   let fmt_dir_arg = function
diff --git a/test/passing/tests/module_modes.ml b/test/passing/tests/module_modes.ml
index 191bc9bebb..a3e2c117e7 100644
--- a/test/passing/tests/module_modes.ml
+++ b/test/passing/tests/module_modes.ml
@@ -70,3 +70,100 @@ let () =
 let () =
   let module (* 38 *) M (* 39 *) @ (* 40 *) m (* 41 *) = (* 42 *) M (* 43 *) in
   ()
+
+(* test mode on ident *)
+
+module (M @ foo) = struct end
+
+module (M @ foo) : S = struct end
+
+(* No functor args: [bar] should move onto [M] *)
+
+module (M @ foo) @ bar = struct end
+
+module (M @ foo) : S @ bar = struct end
+
+module (F @ foo) () = struct end
+
+module (F @ foo) () : S = struct end
+
+(* There are functor args: [bar] is not allowed to move *)
+
+module (F @ foo) () @ bar = struct end
+
+module (F @ foo) () : S @ bar = struct end
+
+module rec (M @ foo) : S @ bar = struct end
+and (N @ foo) : S @ bar = struct end
+
+module rec (F @ foo) () : S @ bar = struct end
+and (G @ foo) () : S @ bar = struct end
+
+(* attributes *)
+
+module[@a] (M @ foo) = struct end
+
+module[@a] (M @ foo) : S = struct end
+
+module[@a] (M @ foo) @ bar = struct end
+
+module[@a] (M @ foo) : S @ bar = struct end
+
+module[@a] (F @ foo) () = struct end
+
+module[@a] (F @ foo) () : S = struct end
+
+module[@a] (F @ foo) () @ bar = struct end
+
+module[@a] (F @ foo) () : S @ bar = struct end
+
+module rec (M @ foo) = (struct end : S @ bar) [@a]
+and (N @ foo) = (struct end : S @ bar) [@a]
+
+module rec (F @ foo) () = (struct end : S @ bar) [@a]
+and (G @ foo) () = (struct end : S @ bar) [@a]
+
+module rec (M @ foo) : S @ bar = (struct end [@a])
+and (N @ foo) : S @ bar = (struct end [@a])
+
+module rec (F @ foo) () : S @ bar = (struct end [@a])
+and (G @ foo) () : S @ bar = (struct end [@a])
+
+let () =
+  let module (M @ foo) = struct end in ()
+
+let () =
+  let module (M @ foo) : S = struct end in ()
+
+let () =
+  let module (M @ foo) @ bar = struct end in ()
+
+let () =
+  let module (M @ foo) : S @ bar = struct end in ()
+
+let () =
+  let module (F @ foo) () = struct end in ()
+
+let () =
+  let module (F @ foo) () : S = struct end in ()
+
+let () =
+  let module (F @ foo) () @ bar = struct end in ()
+
+let () =
+  let module (F @ foo) () : S @ bar = struct end in ()
+
+(* comments *)
+
+module rec (* 44 *) ( (* 45 *) F (* 46 *) @ (* 47 *) foo (* 48 *)) (* 49 *) () (* 50 *)
+  : (* 51 *) S (* 52 *) @ (* 53 *) bar (* 54 *) = (* 55 *) (struct (* 55 *) end (* 56 *)
+    [@a]) (* 57 *)
+and (* 58 *) (G (* 59 *) @ (* 60 *) foo (* 61 *)) (* 62 *) () (* 63 *)
+  : (* 64 *) S (* 65 *) @ (* 66 *) bar (* 67 *) = (* 68 *) (struct (* 69 *) end (* 70 *)
+    [@a]) (* 71 *)
+
+module (* 72 *) ( (* 73 *) M (* 74 *) @ (* 75 *) foo (* 76 *)) (* 77 *) @ (* 78 *) bar
+  (* 79 *) = (* 80 *) struct (* 81 *) end (* 82 *)
+
+module (* 83 *) ( (* 84 *) M (* 85 *) @ (* 86 *) foo (* 87 *)) (* 88 *)
+  : (* 89 *) S (* 90 *) @ (* 91 *) bar (* 92 *) = (* 93 *) struct (* 94 *) end (* 95 *)
diff --git a/test/passing/tests/module_modes.ml.js-ref b/test/passing/tests/module_modes.ml.js-ref
index 374095ef58..acda94b315 100644
--- a/test/passing/tests/module_modes.ml.js-ref
+++ b/test/passing/tests/module_modes.ml.js-ref
@@ -105,3 +105,138 @@ let () =
   in
   ()
 ;;
+
+(* test mode on ident *)
+
+module (M @ foo) = struct end
+module (M @ foo) : S = struct end
+
+(* No functor args: [bar] should move onto [M] *)
+
+module (M @ foo) @ bar = struct end
+module (M @ foo) : S @ bar = struct end
+module (F @ foo) () = struct end
+module (F @ foo) () : S = struct end
+
+(* There are functor args: [bar] is not allowed to move *)
+
+module (F @ foo) () @ bar = struct end
+module (F @ foo) () : S @ bar = struct end
+
+module rec (M @ foo) : S @ bar = struct end
+and (N @ foo) : S @ bar = struct end
+
+module rec (F @ foo) () : S @ bar = struct end
+and (G @ foo) () : S @ bar = struct end
+
+(* attributes *)
+
+module [@a] (M @ foo) = struct end
+module [@a] (M @ foo) : S = struct end
+module [@a] (M @ foo) @ bar = struct end
+module [@a] (M @ foo) : S @ bar = struct end
+module [@a] (F @ foo) () = struct end
+module [@a] (F @ foo) () : S = struct end
+module [@a] (F @ foo) () @ bar = struct end
+module [@a] (F @ foo) () : S @ bar = struct end
+
+module rec (M @ foo) = (struct end : S @ bar) [@a]
+and (N @ foo) = (struct end : S @ bar) [@a]
+
+module rec (F @ foo) () = (struct end : S @ bar) [@a]
+and (G @ foo) () = (struct end : S @ bar) [@a]
+
+module rec (M @ foo) : S @ bar = struct end [@a]
+and (N @ foo) : S @ bar = struct end [@a]
+
+module rec (F @ foo) () : S @ bar = struct end [@a]
+and (G @ foo) () : S @ bar = struct end [@a]
+
+let () =
+  let module (M @ foo) = struct end in
+  ()
+;;
+
+let () =
+  let module (M @ foo) : S = struct end in
+  ()
+;;
+
+let () =
+  let module (M @ foo) @ bar = struct end in
+  ()
+;;
+
+let () =
+  let module (M @ foo) : S @ bar = struct end in
+  ()
+;;
+
+let () =
+  let module (F @ foo) () = struct end in
+  ()
+;;
+
+let () =
+  let module (F @ foo) () : S = struct end in
+  ()
+;;
+
+let () =
+  let module (F @ foo) () @ bar = struct end in
+  ()
+;;
+
+let () =
+  let module (F @ foo) () : S @ bar = struct end in
+  ()
+;;
+
+(* comments *)
+
+module rec ((* 44 *)
+            (* 45 *)
+  F
+  (* 46 *)
+  @ (* 47 *) foo (* 48 *))
+    (* 49 *)
+  () : (* 51 *) S (* 52 *) @ (* 53 *) bar (* 54 *) =
+(* 50 *)
+(* 55 *) struct
+  (* 55 *)
+end [@a]
+(* 56 *)
+(* 57 *)
+
+and ((* 58 *) G (* 59 *) @ (* 60 *) foo (* 61 *)) (* 62 *) () : (* 64 *) S (* 65 *)
+@ (* 66 *) bar (* 67 *) =
+(* 63 *)
+(* 68 *) struct
+  (* 69 *)
+end [@a]
+(* 70 *)
+(* 71 *)
+
+module ((* 72 *)
+        (* 73 *)
+  M
+  (* 74 *)
+  @ (* 75 *) foo (* 76 *))
+@ (* 78 *) bar (* 79 *) =
+(* 77 *)
+(* 80 *)
+struct
+  (* 81 *)
+end
+(* 82 *)
+
+module ((* 83 *)
+        (* 84 *)
+  M
+  (* 85 *)
+  @ (* 86 *) foo (* 87 *)) : (* 89 *) S (* 90 *) @ (* 91 *) bar (* 92 *) =
+(* 88 *)
+(* 93 *) struct
+  (* 94 *)
+end
+(* 95 *)
diff --git a/test/passing/tests/module_modes.ml.ref b/test/passing/tests/module_modes.ml.ref
index f44751a140..d72b9e1081 100644
--- a/test/passing/tests/module_modes.ml.ref
+++ b/test/passing/tests/module_modes.ml.ref
@@ -102,3 +102,148 @@ let () =
     (* 43 *)
   in
   ()
+
+(* test mode on ident *)
+
+module (M @ foo) = struct end
+
+module (M @ foo) : S = struct end
+
+(* No functor args: [bar] should move onto [M] *)
+
+module (M @ foo) @ bar = struct end
+
+module (M @ foo) : S @ bar = struct end
+
+module (F @ foo) () = struct end
+
+module (F @ foo) () : S = struct end
+
+(* There are functor args: [bar] is not allowed to move *)
+
+module (F @ foo) () @ bar = struct end
+
+module (F @ foo) () : S @ bar = struct end
+
+module rec (M @ foo) : S @ bar = struct end
+
+and (N @ foo) : S @ bar = struct end
+
+module rec (F @ foo) () : S @ bar = struct end
+
+and (G @ foo) () : S @ bar = struct end
+
+(* attributes *)
+
+module [@a] (M @ foo) = struct end
+
+module [@a] (M @ foo) : S = struct end
+
+module [@a] (M @ foo) @ bar = struct end
+
+module [@a] (M @ foo) : S @ bar = struct end
+
+module [@a] (F @ foo) () = struct end
+
+module [@a] (F @ foo) () : S = struct end
+
+module [@a] (F @ foo) () @ bar = struct end
+
+module [@a] (F @ foo) () : S @ bar = struct end
+
+module rec (M @ foo) = (struct end : S @ bar) [@a]
+
+and (N @ foo) = (struct end : S @ bar) [@a]
+
+module rec (F @ foo) () = (struct end : S @ bar) [@a]
+
+and (G @ foo) () = (struct end : S @ bar) [@a]
+
+module rec (M @ foo) : S @ bar = struct end [@a]
+
+and (N @ foo) : S @ bar = struct end [@a]
+
+module rec (F @ foo) () : S @ bar = struct end [@a]
+
+and (G @ foo) () : S @ bar = struct end [@a]
+
+let () =
+  let module (M @ foo) = struct end in
+  ()
+
+let () =
+  let module (M @ foo) : S = struct end in
+  ()
+
+let () =
+  let module (M @ foo) @ bar = struct end in
+  ()
+
+let () =
+  let module (M @ foo) : S @ bar = struct end in
+  ()
+
+let () =
+  let module (F @ foo) () = struct end in
+  ()
+
+let () =
+  let module (F @ foo) () : S = struct end in
+  ()
+
+let () =
+  let module (F @ foo) () @ bar = struct end in
+  ()
+
+let () =
+  let module (F @ foo) () : S @ bar = struct end in
+  ()
+
+(* comments *)
+
+module rec ((* 44 *)
+            (* 45 *)
+F
+(* 46 *)
+@ (* 47 *) foo (* 48 *))
+    (* 49 *)
+() : (* 51 *) S (* 52 *) @ (* 53 *) bar (* 54 *) =
+(* 50 *)
+(* 55 *) struct
+  (* 55 *)
+end [@a]
+(* 56 *)
+(* 57 *)
+
+and ((* 58 *) G (* 59 *) @ (* 60 *) foo (* 61 *)) (* 62 *) () : (* 64 *) S
+(* 65 *) @ (* 66 *) bar (* 67 *) =
+(* 63 *)
+(* 68 *) struct
+  (* 69 *)
+end [@a]
+(* 70 *)
+(* 71 *)
+
+module ((* 72 *)
+        (* 73 *)
+M
+(* 74 *)
+@ (* 75 *) foo (* 76 *))
+@ (* 78 *) bar (* 79 *) =
+(* 77 *)
+(* 80 *)
+struct
+  (* 81 *)
+end
+(* 82 *)
+
+module ((* 83 *)
+        (* 84 *)
+M
+(* 85 *)
+@ (* 86 *) foo (* 87 *)) : (* 89 *) S (* 90 *) @ (* 91 *) bar (* 92 *) =
+(* 88 *)
+(* 93 *) struct
+  (* 94 *)
+end
+(* 95 *)
diff --git a/vendor/parser-extended/ast_helper.ml b/vendor/parser-extended/ast_helper.ml
index 234547f653..299cc18a0e 100644
--- a/vendor/parser-extended/ast_helper.ml
+++ b/vendor/parser-extended/ast_helper.ml
@@ -160,7 +160,7 @@ module Exp = struct
   let indexop_access ?loc ?attrs pia_lhs pia_kind pia_paren pia_rhs =
     mk ?loc ?attrs (Pexp_indexop_access {pia_lhs; pia_kind; pia_paren; pia_rhs})
   let override ?loc ?attrs a = mk ?loc ?attrs (Pexp_override a)
-  let letmodule ?loc ?attrs a b c d = mk ?loc ?attrs (Pexp_letmodule (a, b, c, d))
+  let letmodule ?loc ?attrs a b c d e = mk ?loc ?attrs (Pexp_letmodule (a, b, c, d, e))
   let letexception ?loc ?attrs a b = mk ?loc ?attrs (Pexp_letexception (a, b))
   let assert_ ?loc ?attrs a = mk ?loc ?attrs (Pexp_assert a)
   let lazy_ ?loc ?attrs a = mk ?loc ?attrs (Pexp_lazy a)
@@ -432,9 +432,10 @@ end
 
 module Mb = struct
   let mk ?(loc = !default_loc) ?(attrs=Attr.ext_attrs ())
-        ?(docs = empty_docs) ?(text = []) name args expr =
+        ?(docs = empty_docs) ?(text = []) name modes args expr =
     {
      pmb_name = name;
+     pmb_modes = modes;
      pmb_args = args;
      pmb_expr = expr;
      pmb_ext_attrs = add_text_attrs' text (add_docs_attrs' docs attrs);
diff --git a/vendor/parser-extended/ast_mapper.ml b/vendor/parser-extended/ast_mapper.ml
index 9a791f7485..477627648b 100644
--- a/vendor/parser-extended/ast_mapper.ml
+++ b/vendor/parser-extended/ast_mapper.ml
@@ -665,8 +665,9 @@ module E = struct
     | Pexp_override sel ->
         override ~loc ~attrs
           (List.map (map_tuple (map_loc sub) (sub.expr sub)) sel)
-    | Pexp_letmodule (s, args, me, e) ->
+    | Pexp_letmodule (s, m, args, me, e) ->
         letmodule ~loc ~attrs (map_loc sub s)
+          (sub.modes sub m)
           (List.map (map_functor_param sub) args)
           (sub.module_expr sub me)
           (sub.expr sub e)
@@ -947,8 +948,9 @@ let default_mapper =
       );
 
     module_binding =
-      (fun this {pmb_name; pmb_args; pmb_expr; pmb_ext_attrs; pmb_loc} ->
+      (fun this {pmb_name; pmb_modes; pmb_args; pmb_expr; pmb_ext_attrs; pmb_loc} ->
          Mb.mk (map_loc this pmb_name)
+           (this.modes this pmb_modes)
            (List.map (map_functor_param this) pmb_args)
            (this.module_expr this pmb_expr)
            ~attrs:(this.ext_attrs this pmb_ext_attrs)
diff --git a/vendor/parser-extended/parser.mly b/vendor/parser-extended/parser.mly
index 95bed77997..ef64a6b87f 100644
--- a/vendor/parser-extended/parser.mly
+++ b/vendor/parser-extended/parser.mly
@@ -1697,14 +1697,15 @@ structure_item:
 %inline module_binding:
   MODULE
   ext = ext attrs1 = attributes
-  name = mkrhs(module_name)
+  name_ = module_name_modal(at_mode_expr)
   args = functor_args
   body = module_binding_body
   attrs2 = post_item_attributes
     { let docs = symbol_docs $sloc in
       let loc = make_loc $sloc in
       let attrs = Attr.ext_attrs ?ext ~before:attrs1 ~after:attrs2 () in
-      let body = Mb.mk name args body ~attrs ~loc ~docs in
+      let name, modes = name_ in
+      let body = Mb.mk name modes args body ~attrs ~loc ~docs in
       Pstr_module body }
 ;
 
@@ -1747,7 +1748,7 @@ module_binding_body:
   ext = ext
   attrs1 = attributes
   REC
-  name = mkrhs(module_name)
+  name_ = module_name_modal(at_mode_expr)
   args = functor_args
   body = module_binding_body
   attrs2 = post_item_attributes
@@ -1755,7 +1756,8 @@ module_binding_body:
     let loc = make_loc $sloc in
     let attrs = Attr.ext_attrs ?ext ~before:attrs1 ~after:attrs2 () in
     let docs = symbol_docs $sloc in
-    Mb.mk name args body ~attrs ~loc ~docs
+    let name, modes = name_ in
+    Mb.mk name modes args body ~attrs ~loc ~docs
   }
 ;
 
@@ -1763,7 +1765,7 @@ module_binding_body:
 %inline and_module_binding:
   AND
   attrs1 = attributes
-  name = mkrhs(module_name)
+  name_ = module_name_modal(at_mode_expr)
   args = functor_args
   body = module_binding_body
   attrs2 = post_item_attributes
@@ -1772,7 +1774,8 @@ module_binding_body:
     let attrs = Attr.ext_attrs ~before:attrs1 ~after:attrs2 () in
     let docs = symbol_docs $sloc in
     let text = symbol_text $symbolstartpos in
-    Mb.mk name args body ~attrs ~loc ~text ~docs
+    let name, modes = name_ in
+    Mb.mk name modes args body ~attrs ~loc ~text ~docs
   }
 ;
 
@@ -2703,8 +2706,9 @@ expr:
      { mkexp_exclave ~loc:$sloc $2 }
 ;
 %inline expr_attrs:
-  | LET MODULE ext_attributes mkrhs(module_name) functor_args module_binding_body IN seq_expr
-      { Pexp_letmodule($4, $5, $6, $8), $3 }
+  | LET MODULE ext_attributes module_name_modal(at_mode_expr) functor_args module_binding_body IN seq_expr
+      { let name, modes = $4 in
+        Pexp_letmodule(name, modes, $5, $6, $8), $3 }
   | LET EXCEPTION ext_attributes let_exception_declaration IN seq_expr
       { Pexp_letexception($4, $6), $3 }
   | LET OPEN override_flag ext_attributes module_expr IN seq_expr
diff --git a/vendor/parser-extended/parsetree.mli b/vendor/parser-extended/parsetree.mli
index 84c4f1ff6a..c74f81b753 100644
--- a/vendor/parser-extended/parsetree.mli
+++ b/vendor/parser-extended/parsetree.mli
@@ -499,7 +499,7 @@ and expression_desc =
   | Pexp_setinstvar of label loc * expression  (** [x <- 2] *)
   | Pexp_override of (label loc * expression) list
       (** [{< x1 = E1; ...; xn = En >}] *)
-  | Pexp_letmodule of string option loc * functor_parameter loc list * module_expr * expression
+  | Pexp_letmodule of string option loc * modes * functor_parameter loc list * module_expr * expression
       (** [let module M = ME in E] *)
   | Pexp_letexception of extension_constructor * expression
       (** [let exception C in E] *)
@@ -1290,6 +1290,8 @@ and value_bindings =
 and module_binding =
     {
      pmb_name: string option loc;
+     pmb_modes: modes;
+     (** The modes on the identifier *)
      pmb_args: functor_parameter loc list;
      pmb_expr: module_expr;
      pmb_ext_attrs : ext_attrs;
diff --git a/vendor/parser-extended/printast.ml b/vendor/parser-extended/printast.ml
index 6cdd1a6dfe..a8a7148662 100644
--- a/vendor/parser-extended/printast.ml
+++ b/vendor/parser-extended/printast.ml
@@ -513,8 +513,9 @@ and expression i ppf x =
   | Pexp_override (l) ->
       line i ppf "Pexp_override\n";
       list i string_x_expression ppf l;
-  | Pexp_letmodule (s, args, me, e) ->
+  | Pexp_letmodule (s, m, args, me, e) ->
       line i ppf "Pexp_letmodule %a\n" fmt_str_opt_loc s;
+      modes i ppf m;
       list i functor_parameter ppf args;
       module_expr i ppf me;
       expression i ppf e;
@@ -1214,6 +1215,7 @@ and module_declaration i ppf pmd =
 and module_binding i ppf x =
   line i ppf "module_binding %a %a\n" fmt_str_opt_loc x.pmb_name
     fmt_location x.pmb_loc;
+  modes i ppf x.pmb_modes;
   list i functor_parameter ppf x.pmb_args;
   ext_attrs i ppf x.pmb_ext_attrs;
   module_expr (i+1) ppf x.pmb_expr
diff --git a/vendor/parser-standard/parser.mly b/vendor/parser-standard/parser.mly
index aef0fdce3c..492b3adfc1 100644
--- a/vendor/parser-standard/parser.mly
+++ b/vendor/parser-standard/parser.mly
@@ -975,7 +975,10 @@ let unboxed_type sloc lident tys =
 let maybe_pmod_constraint mode expr =
   match mode with
   | [] -> expr
-  | _ :: _ -> Mod.constraint_ None mode expr
+  | _ :: _ ->
+      match expr.pmod_desc with
+      | Pmod_constraint (me, mty, []) -> { expr with pmod_desc = Pmod_constraint (me, mty, mode) }
+      | _ -> Mod.constraint_ None mode expr
 %}
 
 /* Tokens */