diff --git a/compiler/frontend/ast_core_type.ml b/compiler/frontend/ast_core_type.ml
index 9d3c7e05f2..faf9b8f954 100644
--- a/compiler/frontend/ast_core_type.ml
+++ b/compiler/frontend/ast_core_type.ml
@@ -156,7 +156,7 @@ let mk_fn_type (new_arg_types_ty : param_type list) (result : t) : t =
 let list_of_arrow (ty : t) : t * param_type list =
   let rec aux (ty : t) acc =
     match ty.ptyp_desc with
-    | Ptyp_arrow (label, t1, t2, _) ->
+    | Ptyp_arrow (label, t1, t2, arity) when arity = None || acc = [] ->
       aux t2
         (({label; ty = t1; attr = ty.ptyp_attributes; loc = ty.ptyp_loc}
            : param_type)
diff --git a/compiler/frontend/ast_derive_js_mapper.ml b/compiler/frontend/ast_derive_js_mapper.ml
index 7596e970a5..7336fcc0db 100644
--- a/compiler/frontend/ast_derive_js_mapper.ml
+++ b/compiler/frontend/ast_derive_js_mapper.ml
@@ -130,7 +130,7 @@ let app1 = Ast_compatible.app1
 let app2 = Ast_compatible.app2
 
 let ( ->~ ) a b =
-  Ast_uncurried.uncurried_type ~loc:Location.none ~arity:1
+  Ast_uncurried.uncurried_type ~arity:1
     (Ast_compatible.arrow ~arity:(Some 1) a b)
 
 let raise_when_not_found_ident =
@@ -295,7 +295,7 @@ let init () =
               let pat_from_js = {Asttypes.loc; txt = from_js} in
               let to_js_type result =
                 Ast_comb.single_non_rec_val pat_to_js
-                  (Ast_uncurried.uncurried_type ~loc:Location.none ~arity:1
+                  (Ast_uncurried.uncurried_type ~arity:1
                      (Ast_compatible.arrow ~arity:(Some 1) core_type result))
               in
               let new_type, new_tdcl =
diff --git a/compiler/frontend/ast_derive_projector.ml b/compiler/frontend/ast_derive_projector.ml
index a35972018e..26c94a51ca 100644
--- a/compiler/frontend/ast_derive_projector.ml
+++ b/compiler/frontend/ast_derive_projector.ml
@@ -120,9 +120,8 @@ let init () =
             Ext_list.flat_map tdcls handle_tdcl);
         signature_gen =
           (fun (tdcls : Parsetree.type_declaration list) _explict_nonrec ->
-            let handle_uncurried_type_tranform ~loc ~arity t =
-              if arity > 0 then Ast_uncurried.uncurried_type ~loc ~arity t
-              else t
+            let handle_uncurried_type_tranform ~arity t =
+              if arity > 0 then Ast_uncurried.uncurried_type ~arity t else t
             in
             let handle_tdcl tdcl =
               let core_type =
@@ -142,8 +141,7 @@ let init () =
                     Ast_comb.single_non_rec_val ?attrs:gentype_attrs pld_name
                       (Ast_compatible.arrow ~arity:None core_type pld_type
                       (*arity will alwys be 1 since these are single param functions*)
-                      |> handle_uncurried_type_tranform ~arity:1
-                           ~loc:pld_name.loc))
+                      |> handle_uncurried_type_tranform ~arity:1))
               | Ptype_variant constructor_declarations ->
                 Ext_list.map constructor_declarations
                   (fun
@@ -170,7 +168,7 @@ let init () =
                       {loc; txt = Ext_string.uncapitalize_ascii con_name}
                       (Ext_list.fold_right pcd_args annotate_type (fun x acc ->
                            Ast_compatible.arrow ~arity:None x acc)
-                      |> handle_uncurried_type_tranform ~arity ~loc))
+                      |> handle_uncurried_type_tranform ~arity))
               | Ptype_open | Ptype_abstract ->
                 Ast_derive_util.not_applicable tdcl.ptype_loc deriving_name;
                 []
diff --git a/compiler/frontend/ast_exp_handle_external.ml b/compiler/frontend/ast_exp_handle_external.ml
index 27f7afa502..437e12dbe2 100644
--- a/compiler/frontend/ast_exp_handle_external.ml
+++ b/compiler/frontend/ast_exp_handle_external.ml
@@ -133,7 +133,7 @@ let handle_ffi ~loc ~payload =
       match !is_function with
       | Some arity ->
         let type_ =
-          Ast_uncurried.uncurried_type ~loc
+          Ast_uncurried.uncurried_type
             ~arity:(if arity = 0 then 1 else arity)
             (arrow ~arity)
         in
diff --git a/compiler/frontend/ast_external_process.ml b/compiler/frontend/ast_external_process.ml
index c5464862fa..ebf393852f 100644
--- a/compiler/frontend/ast_external_process.ml
+++ b/compiler/frontend/ast_external_process.ml
@@ -938,7 +938,7 @@ let handle_attributes (loc : Bs_loc.t) (type_annotation : Parsetree.core_type)
     | {ptyp_desc = Ptyp_arrow (_, _, _, Some _); _} as t ->
       ( t,
         fun ~arity (x : Parsetree.core_type) ->
-          Ast_uncurried.uncurried_type ~loc ~arity x )
+          Ast_uncurried.uncurried_type ~arity x )
     | _ -> (type_annotation, fun ~arity:_ x -> x)
   in
   let result_type, arg_types_ty =
diff --git a/compiler/frontend/ast_typ_uncurry.ml b/compiler/frontend/ast_typ_uncurry.ml
index c79daf08ba..0b4f2a8692 100644
--- a/compiler/frontend/ast_typ_uncurry.ml
+++ b/compiler/frontend/ast_typ_uncurry.ml
@@ -66,5 +66,5 @@ let to_uncurry_type loc (mapper : Bs_ast_mapper.mapper)
     | _ -> assert false
   in
   match arity with
-  | Some arity -> Ast_uncurried.uncurried_type ~loc ~arity fn_type
+  | Some arity -> Ast_uncurried.uncurried_type ~arity fn_type
   | None -> assert false
diff --git a/compiler/ml/ast_mapper_from0.ml b/compiler/ml/ast_mapper_from0.ml
index b20d40ecf8..3578f7866e 100644
--- a/compiler/ml/ast_mapper_from0.ml
+++ b/compiler/ml/ast_mapper_from0.ml
@@ -120,10 +120,7 @@ module T = struct
           | _ -> assert false
         in
         let arity = arity_from_type t_arity in
-        let fun_t =
-          {fun_t with ptyp_desc = Ptyp_arrow (lbl, t1, t2, Some arity)}
-        in
-        {typ0 with ptyp_desc = Ptyp_constr (lid, [fun_t])}
+        {fun_t with ptyp_desc = Ptyp_arrow (lbl, t1, t2, Some arity)}
       | _ -> typ0)
     | Ptyp_object (l, o) ->
       object_ ~loc ~attrs (List.map (object_field sub) l) o
diff --git a/compiler/ml/ast_mapper_to0.ml b/compiler/ml/ast_mapper_to0.ml
index 57ff7f440d..2f30496b9b 100644
--- a/compiler/ml/ast_mapper_to0.ml
+++ b/compiler/ml/ast_mapper_to0.ml
@@ -98,20 +98,21 @@ module T = struct
     match desc with
     | Ptyp_any -> any ~loc ~attrs ()
     | Ptyp_var s -> var ~loc ~attrs s
-    | Ptyp_arrow (lab, t1, t2, _) ->
-      arrow ~loc ~attrs lab (sub.typ sub t1) (sub.typ sub t2)
+    | Ptyp_arrow (lab, t1, t2, arity) -> (
+      let typ0 = arrow ~loc ~attrs lab (sub.typ sub t1) (sub.typ sub t2) in
+      match arity with
+      | None -> typ0
+      | Some arity ->
+        let arity_string = "Has_arity" ^ string_of_int arity in
+        let arity_type =
+          Ast_helper0.Typ.variant ~loc
+            [Rtag (Location.mknoloc arity_string, [], true, [])]
+            Closed None
+        in
+        Ast_helper0.Typ.constr ~loc
+          {txt = Lident "function$"; loc}
+          [typ0; arity_type])
     | Ptyp_tuple tyl -> tuple ~loc ~attrs (List.map (sub.typ sub) tyl)
-    | Ptyp_constr
-        ( ({txt = Lident "function$"} as lid),
-          [({ptyp_desc = Ptyp_arrow (_, _, _, Some arity)} as t_arg)] ) ->
-      let encode_arity_string arity = "Has_arity" ^ string_of_int arity in
-      let arity_type ~loc arity =
-        Ast_helper0.Typ.variant ~loc
-          [Rtag ({txt = encode_arity_string arity; loc}, [], true, [])]
-          Closed None
-      in
-      constr ~loc ~attrs (map_loc sub lid)
-        [sub.typ sub t_arg; arity_type ~loc:Location.none arity]
     | Ptyp_constr (lid, tl) ->
       constr ~loc ~attrs (map_loc sub lid) (List.map (sub.typ sub) tl)
     | Ptyp_object (l, o) ->
diff --git a/compiler/ml/ast_uncurried.ml b/compiler/ml/ast_uncurried.ml
index 6c12b2731b..d93fb94bfc 100644
--- a/compiler/ml/ast_uncurried.ml
+++ b/compiler/ml/ast_uncurried.ml
@@ -1,13 +1,10 @@
 (* Uncurried AST *)
 
-let uncurried_type ~loc ~arity (t_arg : Parsetree.core_type) =
-  let t_arg =
-    match t_arg.ptyp_desc with
-    | Ptyp_arrow (l, t1, t2, _) ->
-      {t_arg with ptyp_desc = Ptyp_arrow (l, t1, t2, Some arity)}
-    | _ -> assert false
-  in
-  Ast_helper.Typ.constr ~loc {txt = Lident "function$"; loc} [t_arg]
+let uncurried_type ~arity (t_arg : Parsetree.core_type) =
+  match t_arg.ptyp_desc with
+  | Ptyp_arrow (l, t1, t2, _) ->
+    {t_arg with ptyp_desc = Ptyp_arrow (l, t1, t2, Some arity)}
+  | _ -> assert false
 
 let uncurried_fun ~arity fun_expr =
   let fun_expr =
@@ -44,8 +41,9 @@ let tarrow_to_arity_opt (t_arity : Types.type_expr) =
   | _ -> None
 
 let make_uncurried_type ~env ~arity (t : Types.type_expr) =
-  let lid : Longident.t = Lident "function$" in
-  let path = Env.lookup_type lid env in
+  (* let lid : Longident.t = Lident "function$" in
+     let path = Env.lookup_type lid env in *)
+  let _ = env in
   let t =
     match t.desc with
     | Tarrow (l, t1, t2, c, _) ->
@@ -54,17 +52,13 @@ let make_uncurried_type ~env ~arity (t : Types.type_expr) =
     | Tvar _ -> t
     | _ -> assert false
   in
-  Ctype.newconstr path [t]
+  t
 
 let uncurried_type_get_arity ~env typ =
-  match (Ctype.expand_head env typ).desc with
-  | Tconstr (Pident {name = "function$"}, [t], _) -> tarrow_to_arity t
-  | _ -> assert false
+  tarrow_to_arity (Ctype.expand_head env typ)
 
 let uncurried_type_get_arity_opt ~env typ =
-  match (Ctype.expand_head env typ).desc with
-  | Tconstr (Pident {name = "function$"}, [t], _) -> Some (tarrow_to_arity t)
-  | _ -> None
+  tarrow_to_arity_opt (Ctype.expand_head env typ)
 
 let remove_function_dollar ?env typ =
   match
@@ -73,15 +67,12 @@ let remove_function_dollar ?env typ =
     | None -> Ctype.repr typ)
       .desc
   with
-  | Tconstr (Pident {name = "function$"}, [t], _) -> t
   | _ -> typ
 
 let core_type_remove_function_dollar (typ : Parsetree.core_type) =
   match typ.ptyp_desc with
-  | Ptyp_constr ({txt = Lident "function$"}, [t]) -> t
   | _ -> typ
 
 let tcore_type_remove_function_dollar (typ : Typedtree.core_type) =
   match typ.ctyp_desc with
-  | Ttyp_constr (Pident {name = "function$"}, _, [t]) -> t
   | _ -> typ
diff --git a/compiler/ml/oprint.ml b/compiler/ml/oprint.ml
index 93dd3afe4f..153d68fb18 100644
--- a/compiler/ml/oprint.ml
+++ b/compiler/ml/oprint.ml
@@ -249,7 +249,7 @@ let rec print_out_type ppf = function
   | ty -> print_out_type_1 ppf ty
 
 and print_out_type_1 ppf = function
-  | Otyp_arrow (lab, ty1, ty2) ->
+  | Otyp_arrow (lab, ty1, ty2, _) ->
     pp_open_box ppf 0;
     if lab <> "" then (
       pp_print_string ppf lab;
@@ -271,24 +271,6 @@ and print_simple_out_type ppf = function
     fprintf ppf "@[%a%s#%a@]" print_typargs tyl
       (if ng then "_" else "")
       print_ident id
-  | Otyp_constr (Oide_dot (Oide_dot (Oide_ident "Js", "Fn"), name), [tyl]) ->
-    let res =
-      if name = "arity0" then
-        Otyp_arrow ("", Otyp_constr (Oide_ident "unit", []), tyl)
-      else tyl
-    in
-    fprintf ppf "@[<0>(%a@ [@bs])@]" print_out_type_1 res
-  | Otyp_constr (Oide_dot (Oide_dot (Oide_ident "Js_OO", "Meth"), name), [tyl])
-    ->
-    let res =
-      if name = "arity0" then
-        Otyp_arrow ("", Otyp_constr (Oide_ident "unit", []), tyl)
-      else tyl
-    in
-    fprintf ppf "@[<0>(%a@ [@meth])@]" print_out_type_1 res
-  | Otyp_constr (Oide_dot (Oide_dot (Oide_ident "Js_OO", "Callback"), _), [tyl])
-    ->
-    fprintf ppf "@[<0>(%a@ [@this])@]" print_out_type_1 tyl
   | Otyp_constr (id, tyl) ->
     pp_open_box ppf 0;
     print_typargs ppf tyl;
diff --git a/compiler/ml/outcometree.ml b/compiler/ml/outcometree.ml
index dcd620b5e6..13724209fa 100644
--- a/compiler/ml/outcometree.ml
+++ b/compiler/ml/outcometree.ml
@@ -53,7 +53,7 @@ type out_type =
   | Otyp_abstract
   | Otyp_open
   | Otyp_alias of out_type * string
-  | Otyp_arrow of string * out_type * out_type
+  | Otyp_arrow of string * out_type * out_type * Asttypes.arity
   | Otyp_class of bool * out_ident * out_type list
   | Otyp_constr of out_ident * out_type list
   | Otyp_manifest of out_type * out_type
diff --git a/compiler/ml/parsetree.ml b/compiler/ml/parsetree.ml
index 7ee86f3d17..c4f56214c1 100644
--- a/compiler/ml/parsetree.ml
+++ b/compiler/ml/parsetree.ml
@@ -224,8 +224,7 @@ and expression_desc =
     (* let P1 = E1 and ... and Pn = EN in E       (flag = Nonrecursive)
        let rec P1 = E1 and ... and Pn = EN in E   (flag = Recursive)
     *)
-  | Pexp_fun of
-      arg_label * expression option * pattern * expression * int option
+  | Pexp_fun of arg_label * expression option * pattern * expression * arity
     (* fun P -> E1                          (Simple, None)
        fun ~l:P -> E1                       (Labelled l, None)
        fun ?l:P -> E1                       (Optional l, None)
diff --git a/compiler/ml/printtyp.ml b/compiler/ml/printtyp.ml
index ab990159e7..90a9fa1289 100644
--- a/compiler/ml/printtyp.ml
+++ b/compiler/ml/printtyp.ml
@@ -587,7 +587,7 @@ let rec tree_of_typexp sch ty =
         let non_gen = is_non_gen sch ty in
         let name_gen = if non_gen then new_weak_name ty else new_name in
         Otyp_var (non_gen, name_of_type name_gen ty)
-      | Tarrow (l, ty1, ty2, _, _) ->
+      | Tarrow (l, ty1, ty2, _, arity) ->
         let pr_arrow l ty1 ty2 =
           let lab = string_of_label l in
           let t1 =
@@ -599,7 +599,8 @@ let rec tree_of_typexp sch ty =
               | _ -> Otyp_stuff "<hidden>"
             else tree_of_typexp sch ty1
           in
-          Otyp_arrow (lab, t1, tree_of_typexp sch ty2)
+          (* should pass arity here? *)
+          Otyp_arrow (lab, t1, tree_of_typexp sch ty2, arity)
         in
         pr_arrow l ty1 ty2
       | Ttuple tyl -> Otyp_tuple (tree_of_typlist sch tyl)
diff --git a/compiler/ml/typecore.ml b/compiler/ml/typecore.ml
index 8ef3fbfa89..deb9a2b63a 100644
--- a/compiler/ml/typecore.ml
+++ b/compiler/ml/typecore.ml
@@ -75,7 +75,6 @@ type error =
   | Literal_overflow of string
   | Unknown_literal of string * char
   | Illegal_letrec_pat
-  | Labels_omitted of string list
   | Empty_record_literal
   | Uncurried_arity_mismatch of type_expr * int * int
   | Field_not_optional of string * type_expr
@@ -1945,7 +1944,7 @@ let rec list_labels_aux env visited ls ty_fun =
   if List.memq ty visited then (List.rev ls, false)
   else
     match ty.desc with
-    | Tarrow (l, _, ty_res, _, _) ->
+    | Tarrow (l, _, ty_res, _, arity) when arity = None || visited = [] ->
       list_labels_aux env (ty :: visited) (l :: ls) ty_res
     | _ -> (List.rev ls, is_Tvar ty)
 
@@ -3539,7 +3538,7 @@ and type_application ?type_clash_context total_app env funct (sargs : sargs) :
       in
       unify_exp env funct uncurried_typ
     else if
-      Ast_uncurried.tarrow_to_arity_opt
+      Ast_uncurried.uncurried_type_get_arity_opt ~env
         (Ast_uncurried.remove_function_dollar ~env funct.exp_type)
       = None
     then
@@ -3700,23 +3699,6 @@ and type_application ?type_clash_context total_app env funct (sargs : sargs) :
       type_unknown_args max_arity ~args ~top_arity omitted ty_fun0
         sargs (* This is the hot path for non-labeled function*)
   in
-  let () =
-    let ls, tvar = list_labels env funct.exp_type in
-    if not tvar then
-      let labels = Ext_list.filter ls (fun l -> not (is_optional l)) in
-      if
-        Ext_list.same_length labels sargs
-        && List.for_all (fun (l, _) -> l = Nolabel) sargs
-        && List.exists (fun l -> l <> Nolabel) labels
-      then
-        raise
-          (Error
-             ( funct.exp_loc,
-               env,
-               Labels_omitted
-                 (List.map Printtyp.string_of_label
-                    (Ext_list.filter labels (fun x -> x <> Nolabel))) ))
-  in
   if total_app then force_uncurried_type funct;
   let ty, max_arity = extract_uncurried_type funct in
   let top_arity = if total_app then Some max_arity else None in
@@ -3728,7 +3710,7 @@ and type_application ?type_clash_context total_app env funct (sargs : sargs) :
     in
     let exp = type_expect env sarg ty_arg in
     (match (expand_head env exp.exp_type).desc with
-    | Tarrow _ ->
+    | Tarrow _ when not total_app ->
       Location.prerr_warning exp.exp_loc Warnings.Partial_application
     | Tvar _ ->
       Delayed_checks.add_delayed_check (fun () ->
@@ -4345,23 +4327,6 @@ let report_error env ppf error =
     let arity_a = arity_a |> string_of_int in
     let arity_b = arity_b |> string_of_int in
     report_arity_mismatch ~arity_a ~arity_b ppf
-  | Expr_type_clash
-      ( ( _,
-          {
-            desc =
-              Tconstr
-                (Pdot (Pdot (Pident {name = "Js_OO"}, "Meth", _), a, _), _, _);
-          } )
-        :: ( _,
-             {
-               desc =
-                 Tconstr
-                   (Pdot (Pdot (Pident {name = "Js_OO"}, "Meth", _), b, _), _, _);
-             } )
-        :: _,
-        _ )
-    when a <> b ->
-    fprintf ppf "This method has %s but was expected %s" a b
   | Expr_type_clash (trace, type_clash_context) ->
     (* modified *)
     fprintf ppf "@[<v>";
@@ -4544,16 +4509,6 @@ let report_error env ppf error =
     fprintf ppf "Unknown modifier '%c' for literal %s%c" m n m
   | Illegal_letrec_pat ->
     fprintf ppf "Only variables are allowed as left-hand side of `let rec'"
-  | Labels_omitted [label] ->
-    fprintf ppf
-      "Label ~%s was omitted in the application of this labeled function." label
-  | Labels_omitted labels ->
-    let labels_string =
-      labels |> List.map (fun label -> "~" ^ label) |> String.concat ", "
-    in
-    fprintf ppf
-      "Labels %s were omitted in the application of this labeled function."
-      labels_string
   | Empty_record_literal ->
     fprintf ppf
       "Empty record literal {} should be type annotated or used in a record \
diff --git a/compiler/ml/typecore.mli b/compiler/ml/typecore.mli
index 35749847b0..6d69191021 100644
--- a/compiler/ml/typecore.mli
+++ b/compiler/ml/typecore.mli
@@ -118,7 +118,6 @@ type error =
   | Literal_overflow of string
   | Unknown_literal of string * char
   | Illegal_letrec_pat
-  | Labels_omitted of string list
   | Empty_record_literal
   | Uncurried_arity_mismatch of type_expr * int * int
   | Field_not_optional of string * type_expr
diff --git a/compiler/ml/typedtree.ml b/compiler/ml/typedtree.ml
index e909a46b9f..43d13cf450 100644
--- a/compiler/ml/typedtree.ml
+++ b/compiler/ml/typedtree.ml
@@ -78,7 +78,7 @@ and expression_desc =
   | Texp_let of rec_flag * value_binding list * expression
   | Texp_function of {
       arg_label: arg_label;
-      arity: int option;
+      arity: arity;
       param: Ident.t;
       case: case;
       partial: partial;
diff --git a/compiler/ml/typedtree.mli b/compiler/ml/typedtree.mli
index f75fdfa8f7..d6c6988078 100644
--- a/compiler/ml/typedtree.mli
+++ b/compiler/ml/typedtree.mli
@@ -132,7 +132,7 @@ and expression_desc =
          *)
   | Texp_function of {
       arg_label: arg_label;
-      arity: int option;
+      arity: arity;
       param: Ident.t;
       case: case;
       partial: partial;
diff --git a/compiler/syntax/src/res_core.ml b/compiler/syntax/src/res_core.ml
index e678dd9092..80a2ce2dde 100644
--- a/compiler/syntax/src/res_core.ml
+++ b/compiler/syntax/src/res_core.ml
@@ -4074,7 +4074,7 @@ and parse_poly_type_expr p =
         let t_fun =
           Ast_helper.Typ.arrow ~loc ~arity:None Asttypes.Nolabel typ return_type
         in
-        Ast_uncurried.uncurried_type ~loc ~arity:1 t_fun
+        Ast_uncurried.uncurried_type ~arity:1 t_fun
       | _ -> Ast_helper.Typ.var ~loc:var.loc var.txt)
     | _ -> assert false)
   | _ -> parse_typ_expr p
@@ -4429,7 +4429,7 @@ and parse_es6_arrow_type ~attrs p =
             Ast_helper.Typ.arrow ~loc ~attrs ~arity:None arg_lbl typ t
           in
           if param_num = 1 then
-            (param_num - 1, Ast_uncurried.uncurried_type ~loc ~arity t_arg, 1)
+            (param_num - 1, Ast_uncurried.uncurried_type ~arity t_arg, 1)
           else (param_num - 1, t_arg, arity + 1))
         parameters
         (List.length parameters, return_type, return_type_arity + 1)
@@ -4489,7 +4489,7 @@ and parse_arrow_type_rest ~es6_arrow ~start_pos typ p =
     let arrow_typ =
       Ast_helper.Typ.arrow ~loc ~arity:None Asttypes.Nolabel typ return_type
     in
-    Ast_uncurried.uncurried_type ~loc ~arity:1 arrow_typ
+    Ast_uncurried.uncurried_type ~arity:1 arrow_typ
   | _ -> typ
 
 and parse_typ_expr_region p =
@@ -5098,9 +5098,7 @@ and parse_type_equation_or_constr_decl p =
         let arrow_type =
           Ast_helper.Typ.arrow ~loc ~arity:None Asttypes.Nolabel typ return_type
         in
-        let arrow_type =
-          Ast_uncurried.uncurried_type ~loc ~arity:1 arrow_type
-        in
+        let arrow_type = Ast_uncurried.uncurried_type ~arity:1 arrow_type in
 
         let typ = parse_type_alias p arrow_type in
         (Some typ, Asttypes.Public, Parsetree.Ptype_abstract)
diff --git a/compiler/syntax/src/res_outcome_printer.ml b/compiler/syntax/src/res_outcome_printer.ml
index 80feaf742b..e8b97c7815 100644
--- a/compiler/syntax/src/res_outcome_printer.ml
+++ b/compiler/syntax/src/res_outcome_printer.ml
@@ -82,7 +82,8 @@ let print_out_attributes_doc (attrs : Outcometree.out_attribute list) =
 
 let rec collect_arrow_args (out_type : Outcometree.out_type) args =
   match out_type with
-  | Otyp_arrow (label, arg_type, return_type) ->
+  | Otyp_arrow (label, arg_type, return_type, arity)
+    when arity = None || args = [] ->
     let arg = (label, arg_type) in
     collect_arrow_args return_type (arg :: args)
   | _ as return_type -> (List.rev args, return_type)
@@ -147,21 +148,6 @@ let rec print_out_type_doc (out_type : Outcometree.out_type) =
         Doc.text alias_txt;
         Doc.rparen;
       ]
-  | Otyp_constr (Oide_dot (Oide_dot (Oide_ident "Js", "Fn"), "arity0"), [typ])
-    ->
-    (* Compatibility with compiler up to v10.x *)
-    Doc.concat [Doc.text "(. ()) => "; print_out_type_doc typ]
-  | Otyp_constr
-      ( Oide_dot (Oide_dot (Oide_ident "Js", "Fn"), _),
-        [(Otyp_arrow _ as arrow_type)] ) ->
-    (* Compatibility with compiler up to v10.x *)
-    print_out_arrow_type arrow_type
-  | Otyp_constr (Oide_ident "function$", [(Otyp_arrow _ as arrow_type)]) ->
-    (* function$<(int, int) => int> -> (int, int) => int *)
-    print_out_arrow_type arrow_type
-  | Otyp_constr (Oide_ident "function$", [Otyp_var _]) ->
-    (* function$<'a, arity> -> _ => _ *)
-    print_out_type_doc (Otyp_stuff "_ => _")
   | Otyp_constr (out_ident, []) ->
     print_out_ident_doc ~allow_uident:false out_ident
   | Otyp_manifest (typ1, typ2) ->
@@ -295,12 +281,7 @@ and print_out_arrow_type typ =
   let args_doc =
     let needs_parens =
       match typ_args with
-      | [
-       ( _,
-         ( Otyp_tuple _ | Otyp_arrow _
-         | Otyp_constr (Oide_ident "function$", [Otyp_arrow _]) ) );
-      ] ->
-        true
+      | [(_, (Otyp_tuple _ | Otyp_arrow _))] -> true
       (* single argument should not be wrapped *)
       | [("", _)] -> false
       | _ -> true
diff --git a/compiler/syntax/src/res_parsetree_viewer.ml b/compiler/syntax/src/res_parsetree_viewer.ml
index 56d91114de..b61ae36951 100644
--- a/compiler/syntax/src/res_parsetree_viewer.ml
+++ b/compiler/syntax/src/res_parsetree_viewer.ml
@@ -1,12 +1,15 @@
 open Parsetree
 
-let arrow_type ?(max_arity = max_int) ?(attrs = []) ct =
+let arrow_type ?(max_arity = max_int) ct =
   let has_as_attr attrs =
     Ext_list.exists attrs (fun (x, _) -> x.Asttypes.txt = "as")
   in
   let rec process attrs_before acc typ arity =
     match typ with
-    | typ when arity < 0 -> (attrs_before, List.rev acc, typ)
+    | _ when arity < 0 -> (attrs_before, List.rev acc, typ)
+    | {ptyp_desc = Ptyp_arrow (_, _, _, Some _); ptyp_attributes = []}
+      when acc <> [] ->
+      (attrs_before, List.rev acc, typ)
     | {
      ptyp_desc = Ptyp_arrow ((Nolabel as lbl), typ1, typ2, _);
      ptyp_attributes = [];
@@ -51,9 +54,8 @@ let arrow_type ?(max_arity = max_int) ?(attrs = []) ct =
       ptyp_desc = Ptyp_arrow (Nolabel, _typ1, _typ2, _);
       ptyp_attributes = attrs1;
     } as typ ->
-    let attrs = attrs @ attrs1 in
-    process attrs [] {typ with ptyp_attributes = []} max_arity
-  | typ -> process attrs [] typ max_arity
+    process attrs1 [] {typ with ptyp_attributes = []} max_arity
+  | typ -> process [] [] typ max_arity
 
 let functor_type modtype =
   let rec process acc modtype =
diff --git a/compiler/syntax/src/res_parsetree_viewer.mli b/compiler/syntax/src/res_parsetree_viewer.mli
index 56629acd89..f478f1e633 100644
--- a/compiler/syntax/src/res_parsetree_viewer.mli
+++ b/compiler/syntax/src/res_parsetree_viewer.mli
@@ -3,7 +3,6 @@
    * we restructure the tree into (a, b, c) and its returnType d *)
 val arrow_type :
   ?max_arity:int ->
-  ?attrs:Parsetree.attributes ->
   Parsetree.core_type ->
   Parsetree.attributes
   * (Parsetree.attributes * Asttypes.arg_label * Parsetree.core_type) list
diff --git a/compiler/syntax/src/res_printer.ml b/compiler/syntax/src/res_printer.ml
index 6f88b4fc65..a6b3ba0cad 100644
--- a/compiler/syntax/src/res_printer.ml
+++ b/compiler/syntax/src/res_printer.ml
@@ -1587,9 +1587,6 @@ and print_label_declaration ~state (ld : Parsetree.label_declaration) cmt_tbl =
        ])
 
 and print_typ_expr ~(state : State.t) (typ_expr : Parsetree.core_type) cmt_tbl =
-  let parent_attrs =
-    ParsetreeViewer.filter_parsing_attrs typ_expr.ptyp_attributes
-  in
   let print_arrow ~arity typ_expr =
     let max_arity =
       match arity with
@@ -1597,7 +1594,7 @@ and print_typ_expr ~(state : State.t) (typ_expr : Parsetree.core_type) cmt_tbl =
       | None -> max_int
     in
     let attrs_before, args, return_type =
-      ParsetreeViewer.arrow_type ~max_arity ~attrs:parent_attrs typ_expr
+      ParsetreeViewer.arrow_type ~max_arity typ_expr
     in
     let return_type_needs_parens =
       match return_type.ptyp_desc with
diff --git a/tests/analysis_tests/tests-reanalyze/deadcode/expected/deadcode.txt b/tests/analysis_tests/tests-reanalyze/deadcode/expected/deadcode.txt
index 860577fc40..7b5b08f55d 100644
--- a/tests/analysis_tests/tests-reanalyze/deadcode/expected/deadcode.txt
+++ b/tests/analysis_tests/tests-reanalyze/deadcode/expected/deadcode.txt
@@ -981,7 +981,7 @@
   addValueDeclaration +make ImportHookDefault.res:6:0 path:+ImportHookDefault
   addRecordLabelDeclaration name ImportHookDefault.res:2:2 path:+ImportHookDefault.person
   addRecordLabelDeclaration age ImportHookDefault.res:3:2 path:+ImportHookDefault.person
-  addRecordLabelDeclaration person ImportHookDefault.res:8:2 path:+ImportHookDefault.props
+  addRecordLabelDeclaration person ImportHookDefault.res:7:15 path:+ImportHookDefault.props
   addRecordLabelDeclaration children ImportHookDefault.res:9:2 path:+ImportHookDefault.props
   addRecordLabelDeclaration renderMe ImportHookDefault.res:11:5 path:+ImportHookDefault.props
   Scanning ImportHooks.cmt Source:ImportHooks.res
@@ -989,7 +989,7 @@
   addValueDeclaration +foo ImportHooks.res:20:0 path:+ImportHooks
   addRecordLabelDeclaration name ImportHooks.res:3:2 path:+ImportHooks.person
   addRecordLabelDeclaration age ImportHooks.res:4:2 path:+ImportHooks.person
-  addRecordLabelDeclaration person ImportHooks.res:15:2 path:+ImportHooks.props
+  addRecordLabelDeclaration person ImportHooks.res:14:15 path:+ImportHooks.props
   addRecordLabelDeclaration children ImportHooks.res:16:2 path:+ImportHooks.props
   addRecordLabelDeclaration renderMe ImportHooks.res:18:5 path:+ImportHooks.props
   Scanning ImportIndex.cmt Source:ImportIndex.res
@@ -1195,7 +1195,9 @@
   addValueReference OptArg.res:1:4 --> OptArg.res:1:29
   addValueReference OptArg.res:3:4 --> OptArg.res:3:17
   addValueReference OptArg.res:3:4 --> OptArg.res:3:27
+  DeadOptionalArgs.addReferences foo called with optional argNames:x argNamesMaybe: OptArg.res:5:7
   addValueReference OptArg.res:5:7 --> OptArg.res:1:4
+  DeadOptionalArgs.addReferences bar called with optional argNames: argNamesMaybe: OptArg.res:7:7
   addValueReference OptArg.res:7:7 --> OptArg.res:3:4
   addValueReference OptArg.res:9:4 --> OptArg.res:9:20
   addValueReference OptArg.res:9:4 --> OptArg.res:9:26
@@ -1204,20 +1206,25 @@
   addValueReference OptArg.res:9:4 --> OptArg.res:9:23
   addValueReference OptArg.res:9:4 --> OptArg.res:9:29
   addValueReference OptArg.res:9:4 --> OptArg.res:9:35
+  DeadOptionalArgs.addReferences threeArgs called with optional argNames:c, a argNamesMaybe: OptArg.res:11:7
   addValueReference OptArg.res:11:7 --> OptArg.res:9:4
+  DeadOptionalArgs.addReferences threeArgs called with optional argNames:a argNamesMaybe: OptArg.res:12:7
   addValueReference OptArg.res:12:7 --> OptArg.res:9:4
   addValueReference OptArg.res:14:4 --> OptArg.res:14:18
   addValueReference OptArg.res:14:4 --> OptArg.res:14:24
   addValueReference OptArg.res:14:4 --> OptArg.res:14:15
   addValueReference OptArg.res:14:4 --> OptArg.res:14:21
   addValueReference OptArg.res:14:4 --> OptArg.res:14:27
+  DeadOptionalArgs.addReferences twoArgs called with optional argNames: argNamesMaybe: OptArg.res:16:7
   addValueReference OptArg.res:16:12 --> OptArg.res:14:4
   addValueReference OptArg.res:18:4 --> OptArg.res:18:17
   addValueReference OptArg.res:18:4 --> OptArg.res:18:14
   addValueReference OptArg.res:18:4 --> OptArg.res:18:24
+  DeadOptionalArgs.addReferences oneArg called with optional argNames:a argNamesMaybe:a OptArg.res:20:30
   addValueReference OptArg.res:20:4 --> OptArg.res:20:18
   addValueReference OptArg.res:20:4 --> OptArg.res:20:24
   addValueReference OptArg.res:20:4 --> OptArg.res:18:4
+  DeadOptionalArgs.addReferences wrapOneArg called with optional argNames:a argNamesMaybe: OptArg.res:22:7
   addValueReference OptArg.res:22:7 --> OptArg.res:20:4
   addValueReference OptArg.res:24:4 --> OptArg.res:24:19
   addValueReference OptArg.res:24:4 --> OptArg.res:24:25
@@ -1228,15 +1235,20 @@
   addValueReference OptArg.res:24:4 --> OptArg.res:24:28
   addValueReference OptArg.res:24:4 --> OptArg.res:24:34
   addValueReference OptArg.res:24:4 --> OptArg.res:24:40
+  DeadOptionalArgs.addReferences fourArgs called with optional argNames:c, b, a argNamesMaybe:c, b, a OptArg.res:26:44
   addValueReference OptArg.res:26:4 --> OptArg.res:26:20
   addValueReference OptArg.res:26:4 --> OptArg.res:26:26
   addValueReference OptArg.res:26:4 --> OptArg.res:26:32
   addValueReference OptArg.res:26:4 --> OptArg.res:26:38
   addValueReference OptArg.res:26:4 --> OptArg.res:24:4
+  DeadOptionalArgs.addReferences wrapfourArgs called with optional argNames:c, a argNamesMaybe: OptArg.res:28:7
   addValueReference OptArg.res:28:7 --> OptArg.res:26:4
+  DeadOptionalArgs.addReferences wrapfourArgs called with optional argNames:c, b argNamesMaybe: OptArg.res:29:7
   addValueReference OptArg.res:29:7 --> OptArg.res:26:4
   addValueReference OptArg.resi:1:0 --> OptArg.res:1:4
+  OptionalArgs.addFunctionReference OptArg.resi:1:0 OptArg.res:1:4
   addValueReference OptArg.resi:2:0 --> OptArg.res:3:4
+  OptionalArgs.addFunctionReference OptArg.resi:2:0 OptArg.res:3:4
   Scanning OptArg.cmti Source:OptArg.resi
   addValueDeclaration +foo OptArg.resi:1:0 path:OptArg
   addValueDeclaration +bar OptArg.resi:2:0 path:OptArg
@@ -1438,10 +1450,12 @@
   addValueDeclaration +bar TestOptArg.res:5:4 path:+TestOptArg
   addValueDeclaration +notSuppressesOptArgs TestOptArg.res:9:4 path:+TestOptArg
   addValueDeclaration +liveSuppressesOptArgs TestOptArg.res:14:4 path:+TestOptArg
+  DeadOptionalArgs.addReferences OptArg.bar called with optional argNames:z argNamesMaybe: TestOptArg.res:1:7
   addValueReference TestOptArg.res:1:7 --> OptArg.resi:2:0
   addValueReference TestOptArg.res:3:4 --> TestOptArg.res:3:14
   addValueReference TestOptArg.res:3:4 --> TestOptArg.res:3:11
   addValueReference TestOptArg.res:3:4 --> TestOptArg.res:3:17
+  DeadOptionalArgs.addReferences foo called with optional argNames:x argNamesMaybe: TestOptArg.res:5:16
   addValueReference TestOptArg.res:5:4 --> TestOptArg.res:3:4
   addValueReference TestOptArg.res:7:7 --> TestOptArg.res:5:4
   addValueReference TestOptArg.res:9:4 --> TestOptArg.res:9:31
@@ -1451,6 +1465,7 @@
   addValueReference TestOptArg.res:9:4 --> TestOptArg.res:9:34
   addValueReference TestOptArg.res:9:4 --> TestOptArg.res:9:40
   addValueReference TestOptArg.res:9:4 --> TestOptArg.res:9:46
+  DeadOptionalArgs.addReferences notSuppressesOptArgs called with optional argNames: argNamesMaybe: TestOptArg.res:11:8
   addValueReference TestOptArg.res:11:8 --> TestOptArg.res:9:4
   addValueReference TestOptArg.res:14:4 --> TestOptArg.res:14:32
   addValueReference TestOptArg.res:14:4 --> TestOptArg.res:14:38
@@ -1459,6 +1474,7 @@
   addValueReference TestOptArg.res:14:4 --> TestOptArg.res:14:35
   addValueReference TestOptArg.res:14:4 --> TestOptArg.res:14:41
   addValueReference TestOptArg.res:14:4 --> TestOptArg.res:14:47
+  DeadOptionalArgs.addReferences liveSuppressesOptArgs called with optional argNames:x argNamesMaybe: TestOptArg.res:16:8
   addValueReference TestOptArg.res:16:8 --> TestOptArg.res:14:4
   Scanning TestPromise.cmt Source:TestPromise.res
   addValueDeclaration +convert TestPromise.res:14:4 path:+TestPromise
@@ -1667,11 +1683,13 @@
   addTypeReference Unison.res:37:20 --> Unison.res:14:2
   addValueReference Unison.res:37:0 --> Unison.res:26:8
   addTypeReference Unison.res:38:20 --> Unison.res:15:2
+  DeadOptionalArgs.addReferences group called with optional argNames:break argNamesMaybe: Unison.res:38:25
   addTypeReference Unison.res:38:38 --> Unison.res:5:2
   addValueReference Unison.res:38:25 --> Unison.res:17:4
   addTypeReference Unison.res:38:53 --> Unison.res:14:2
   addValueReference Unison.res:38:0 --> Unison.res:26:8
   addTypeReference Unison.res:39:20 --> Unison.res:15:2
+  DeadOptionalArgs.addReferences group called with optional argNames:break argNamesMaybe: Unison.res:39:25
   addTypeReference Unison.res:39:38 --> Unison.res:6:2
   addValueReference Unison.res:39:25 --> Unison.res:17:4
   addTypeReference Unison.res:39:52 --> Unison.res:14:2
@@ -2501,6 +2519,70 @@ File References
   DeadTest.res:153:1-28
   deadIncorrect  is annotated @dead but is live
 
+  Warning Unused Argument
+  TestOptArg.res:9:1-65
+  optional argument x of function notSuppressesOptArgs is never used
+
+  Warning Unused Argument
+  TestOptArg.res:9:1-65
+  optional argument y of function notSuppressesOptArgs is never used
+
+  Warning Unused Argument
+  TestOptArg.res:9:1-65
+  optional argument z of function notSuppressesOptArgs is never used
+
+  Warning Redundant Optional Argument
+  TestOptArg.res:3:1-28
+  optional argument x of function foo is always supplied (1 calls)
+
+  Warning Redundant Optional Argument
+  Unison.res:17:1-60
+  optional argument break of function group is always supplied (2 calls)
+
+  Warning Unused Argument
+  OptArg.resi:2:1-50
+  optional argument x of function bar is never used
+
+  Warning Redundant Optional Argument
+  OptArg.res:26:1-70
+  optional argument c of function wrapfourArgs is always supplied (2 calls)
+
+  Warning Unused Argument
+  OptArg.res:24:1-63
+  optional argument d of function fourArgs is never used
+
+  Warning Redundant Optional Argument
+  OptArg.res:20:1-51
+  optional argument a of function wrapOneArg is always supplied (1 calls)
+
+  Warning Unused Argument
+  OptArg.res:14:1-42
+  optional argument a of function twoArgs is never used
+
+  Warning Unused Argument
+  OptArg.res:14:1-42
+  optional argument b of function twoArgs is never used
+
+  Warning Unused Argument
+  OptArg.res:9:1-54
+  optional argument b of function threeArgs is never used
+
+  Warning Redundant Optional Argument
+  OptArg.res:9:1-54
+  optional argument a of function threeArgs is always supplied (2 calls)
+
+  Warning Unused Argument
+  OptArg.res:3:1-38
+  optional argument x of function bar is never used
+
+  Warning Unused Argument
+  OptArg.res:1:1-48
+  optional argument y of function foo is never used
+
+  Warning Unused Argument
+  OptArg.res:1:1-48
+  optional argument z of function foo is never used
+
   Warning Dead Module
   AutoAnnotate.res:0:1
   AutoAnnotate is a dead module as all its items are dead.
@@ -4167,4 +4249,4 @@ File References
   <-- line 96
   type variant1Object = | @dead("variant1Object.R") R(payload)
   
-  Analysis reported 286 issues (Incorrect Dead Annotation:1, Warning Dead Exception:2, Warning Dead Module:21, Warning Dead Type:87, Warning Dead Value:174, Warning Dead Value With Side Effects:1)
+  Analysis reported 302 issues (Incorrect Dead Annotation:1, Warning Dead Exception:2, Warning Dead Module:21, Warning Dead Type:87, Warning Dead Value:174, Warning Dead Value With Side Effects:1, Warning Redundant Optional Argument:5, Warning Unused Argument:11)
diff --git a/tests/analysis_tests/tests/src/expected/SignatureHelp.res.txt b/tests/analysis_tests/tests/src/expected/SignatureHelp.res.txt
index 09576665b9..1d86e2147d 100644
--- a/tests/analysis_tests/tests/src/expected/SignatureHelp.res.txt
+++ b/tests/analysis_tests/tests/src/expected/SignatureHelp.res.txt
@@ -9,11 +9,12 @@ ContextPath Value[someFunc]
 Path someFunc
 argAtCursor: unlabelled<0>
 extracted params: 
-[int, ~two: string=?, ~three: unit => unit, ~four: someVariant, unit]
+[(
+  int, ~two: string=?, ~three: unit => unit, ~four: someVariant, unit]
 {
   "signatures": [{
     "label": "(\n  int,\n  ~two: string=?,\n  ~three: unit => unit,\n  ~four: someVariant,\n  unit,\n) => unit",
-    "parameters": [{"label": [4, 7], "documentation": {"kind": "markdown", "value": ""}}, {"label": [11, 25], "documentation": {"kind": "markdown", "value": ""}}, {"label": [29, 49], "documentation": {"kind": "markdown", "value": ""}}, {"label": [53, 71], "documentation": {"kind": "markdown", "value": "```rescript\ntype someVariant = One | Two | Three\n```\nGo to: [Type definition](command:rescript-vscode.go_to_location?%5B%22SignatureHelp.res%22%2C0%2C0%5D)"}}, {"label": [75, 79], "documentation": {"kind": "markdown", "value": ""}}],
+    "parameters": [{"label": [0, 7], "documentation": {"kind": "markdown", "value": ""}}, {"label": [11, 25], "documentation": {"kind": "markdown", "value": ""}}, {"label": [29, 49], "documentation": {"kind": "markdown", "value": ""}}, {"label": [53, 71], "documentation": {"kind": "markdown", "value": "```rescript\ntype someVariant = One | Two | Three\n```\nGo to: [Type definition](command:rescript-vscode.go_to_location?%5B%22SignatureHelp.res%22%2C0%2C0%5D)"}}, {"label": [75, 79], "documentation": {"kind": "markdown", "value": ""}}],
     "documentation": {"kind": "markdown", "value": " Does stuff. "}
   }],
   "activeSignature": 0,
@@ -31,11 +32,12 @@ ContextPath Value[someFunc]
 Path someFunc
 argAtCursor: unlabelled<0>
 extracted params: 
-[int, ~two: string=?, ~three: unit => unit, ~four: someVariant, unit]
+[(
+  int, ~two: string=?, ~three: unit => unit, ~four: someVariant, unit]
 {
   "signatures": [{
     "label": "(\n  int,\n  ~two: string=?,\n  ~three: unit => unit,\n  ~four: someVariant,\n  unit,\n) => unit",
-    "parameters": [{"label": [4, 7], "documentation": {"kind": "markdown", "value": ""}}, {"label": [11, 25], "documentation": {"kind": "markdown", "value": ""}}, {"label": [29, 49], "documentation": {"kind": "markdown", "value": ""}}, {"label": [53, 71], "documentation": {"kind": "markdown", "value": "```rescript\ntype someVariant = One | Two | Three\n```\nGo to: [Type definition](command:rescript-vscode.go_to_location?%5B%22SignatureHelp.res%22%2C0%2C0%5D)"}}, {"label": [75, 79], "documentation": {"kind": "markdown", "value": ""}}],
+    "parameters": [{"label": [0, 7], "documentation": {"kind": "markdown", "value": ""}}, {"label": [11, 25], "documentation": {"kind": "markdown", "value": ""}}, {"label": [29, 49], "documentation": {"kind": "markdown", "value": ""}}, {"label": [53, 71], "documentation": {"kind": "markdown", "value": "```rescript\ntype someVariant = One | Two | Three\n```\nGo to: [Type definition](command:rescript-vscode.go_to_location?%5B%22SignatureHelp.res%22%2C0%2C0%5D)"}}, {"label": [75, 79], "documentation": {"kind": "markdown", "value": ""}}],
     "documentation": {"kind": "markdown", "value": " Does stuff. "}
   }],
   "activeSignature": 0,
@@ -53,11 +55,12 @@ ContextPath Value[someFunc]
 Path someFunc
 argAtCursor: ~two
 extracted params: 
-[int, ~two: string=?, ~three: unit => unit, ~four: someVariant, unit]
+[(
+  int, ~two: string=?, ~three: unit => unit, ~four: someVariant, unit]
 {
   "signatures": [{
     "label": "(\n  int,\n  ~two: string=?,\n  ~three: unit => unit,\n  ~four: someVariant,\n  unit,\n) => unit",
-    "parameters": [{"label": [4, 7], "documentation": {"kind": "markdown", "value": ""}}, {"label": [11, 25], "documentation": {"kind": "markdown", "value": ""}}, {"label": [29, 49], "documentation": {"kind": "markdown", "value": ""}}, {"label": [53, 71], "documentation": {"kind": "markdown", "value": "```rescript\ntype someVariant = One | Two | Three\n```\nGo to: [Type definition](command:rescript-vscode.go_to_location?%5B%22SignatureHelp.res%22%2C0%2C0%5D)"}}, {"label": [75, 79], "documentation": {"kind": "markdown", "value": ""}}],
+    "parameters": [{"label": [0, 7], "documentation": {"kind": "markdown", "value": ""}}, {"label": [11, 25], "documentation": {"kind": "markdown", "value": ""}}, {"label": [29, 49], "documentation": {"kind": "markdown", "value": ""}}, {"label": [53, 71], "documentation": {"kind": "markdown", "value": "```rescript\ntype someVariant = One | Two | Three\n```\nGo to: [Type definition](command:rescript-vscode.go_to_location?%5B%22SignatureHelp.res%22%2C0%2C0%5D)"}}, {"label": [75, 79], "documentation": {"kind": "markdown", "value": ""}}],
     "documentation": {"kind": "markdown", "value": " Does stuff. "}
   }],
   "activeSignature": 0,
@@ -75,11 +78,12 @@ ContextPath Value[someFunc]
 Path someFunc
 argAtCursor: ~two
 extracted params: 
-[int, ~two: string=?, ~three: unit => unit, ~four: someVariant, unit]
+[(
+  int, ~two: string=?, ~three: unit => unit, ~four: someVariant, unit]
 {
   "signatures": [{
     "label": "(\n  int,\n  ~two: string=?,\n  ~three: unit => unit,\n  ~four: someVariant,\n  unit,\n) => unit",
-    "parameters": [{"label": [4, 7], "documentation": {"kind": "markdown", "value": ""}}, {"label": [11, 25], "documentation": {"kind": "markdown", "value": ""}}, {"label": [29, 49], "documentation": {"kind": "markdown", "value": ""}}, {"label": [53, 71], "documentation": {"kind": "markdown", "value": "```rescript\ntype someVariant = One | Two | Three\n```\nGo to: [Type definition](command:rescript-vscode.go_to_location?%5B%22SignatureHelp.res%22%2C0%2C0%5D)"}}, {"label": [75, 79], "documentation": {"kind": "markdown", "value": ""}}],
+    "parameters": [{"label": [0, 7], "documentation": {"kind": "markdown", "value": ""}}, {"label": [11, 25], "documentation": {"kind": "markdown", "value": ""}}, {"label": [29, 49], "documentation": {"kind": "markdown", "value": ""}}, {"label": [53, 71], "documentation": {"kind": "markdown", "value": "```rescript\ntype someVariant = One | Two | Three\n```\nGo to: [Type definition](command:rescript-vscode.go_to_location?%5B%22SignatureHelp.res%22%2C0%2C0%5D)"}}, {"label": [75, 79], "documentation": {"kind": "markdown", "value": ""}}],
     "documentation": {"kind": "markdown", "value": " Does stuff. "}
   }],
   "activeSignature": 0,
@@ -97,11 +101,12 @@ ContextPath Value[someFunc]
 Path someFunc
 argAtCursor: ~four
 extracted params: 
-[int, ~two: string=?, ~three: unit => unit, ~four: someVariant, unit]
+[(
+  int, ~two: string=?, ~three: unit => unit, ~four: someVariant, unit]
 {
   "signatures": [{
     "label": "(\n  int,\n  ~two: string=?,\n  ~three: unit => unit,\n  ~four: someVariant,\n  unit,\n) => unit",
-    "parameters": [{"label": [4, 7], "documentation": {"kind": "markdown", "value": ""}}, {"label": [11, 25], "documentation": {"kind": "markdown", "value": ""}}, {"label": [29, 49], "documentation": {"kind": "markdown", "value": ""}}, {"label": [53, 71], "documentation": {"kind": "markdown", "value": "```rescript\ntype someVariant = One | Two | Three\n```\nGo to: [Type definition](command:rescript-vscode.go_to_location?%5B%22SignatureHelp.res%22%2C0%2C0%5D)"}}, {"label": [75, 79], "documentation": {"kind": "markdown", "value": ""}}],
+    "parameters": [{"label": [0, 7], "documentation": {"kind": "markdown", "value": ""}}, {"label": [11, 25], "documentation": {"kind": "markdown", "value": ""}}, {"label": [29, 49], "documentation": {"kind": "markdown", "value": ""}}, {"label": [53, 71], "documentation": {"kind": "markdown", "value": "```rescript\ntype someVariant = One | Two | Three\n```\nGo to: [Type definition](command:rescript-vscode.go_to_location?%5B%22SignatureHelp.res%22%2C0%2C0%5D)"}}, {"label": [75, 79], "documentation": {"kind": "markdown", "value": ""}}],
     "documentation": {"kind": "markdown", "value": " Does stuff. "}
   }],
   "activeSignature": 0,
@@ -119,11 +124,12 @@ ContextPath Value[someFunc]
 Path someFunc
 argAtCursor: ~four
 extracted params: 
-[int, ~two: string=?, ~three: unit => unit, ~four: someVariant, unit]
+[(
+  int, ~two: string=?, ~three: unit => unit, ~four: someVariant, unit]
 {
   "signatures": [{
     "label": "(\n  int,\n  ~two: string=?,\n  ~three: unit => unit,\n  ~four: someVariant,\n  unit,\n) => unit",
-    "parameters": [{"label": [4, 7], "documentation": {"kind": "markdown", "value": ""}}, {"label": [11, 25], "documentation": {"kind": "markdown", "value": ""}}, {"label": [29, 49], "documentation": {"kind": "markdown", "value": ""}}, {"label": [53, 71], "documentation": {"kind": "markdown", "value": "```rescript\ntype someVariant = One | Two | Three\n```\nGo to: [Type definition](command:rescript-vscode.go_to_location?%5B%22SignatureHelp.res%22%2C0%2C0%5D)"}}, {"label": [75, 79], "documentation": {"kind": "markdown", "value": ""}}],
+    "parameters": [{"label": [0, 7], "documentation": {"kind": "markdown", "value": ""}}, {"label": [11, 25], "documentation": {"kind": "markdown", "value": ""}}, {"label": [29, 49], "documentation": {"kind": "markdown", "value": ""}}, {"label": [53, 71], "documentation": {"kind": "markdown", "value": "```rescript\ntype someVariant = One | Two | Three\n```\nGo to: [Type definition](command:rescript-vscode.go_to_location?%5B%22SignatureHelp.res%22%2C0%2C0%5D)"}}, {"label": [75, 79], "documentation": {"kind": "markdown", "value": ""}}],
     "documentation": {"kind": "markdown", "value": " Does stuff. "}
   }],
   "activeSignature": 0,
@@ -141,11 +147,11 @@ ContextPath Value[otherFunc]
 Path otherFunc
 argAtCursor: unlabelled<0>
 extracted params: 
-[string, int, float]
+[(string, int, float]
 {
   "signatures": [{
     "label": "(string, int, float) => unit",
-    "parameters": [{"label": [1, 7], "documentation": {"kind": "markdown", "value": ""}}, {"label": [9, 12], "documentation": {"kind": "markdown", "value": ""}}, {"label": [14, 19], "documentation": {"kind": "markdown", "value": ""}}]
+    "parameters": [{"label": [0, 7], "documentation": {"kind": "markdown", "value": ""}}, {"label": [9, 12], "documentation": {"kind": "markdown", "value": ""}}, {"label": [14, 19], "documentation": {"kind": "markdown", "value": ""}}]
   }],
   "activeSignature": 0,
   "activeParameter": 0
@@ -162,11 +168,11 @@ ContextPath Value[otherFunc]
 Path otherFunc
 argAtCursor: unlabelled<0>
 extracted params: 
-[string, int, float]
+[(string, int, float]
 {
   "signatures": [{
     "label": "(string, int, float) => unit",
-    "parameters": [{"label": [1, 7], "documentation": {"kind": "markdown", "value": ""}}, {"label": [9, 12], "documentation": {"kind": "markdown", "value": ""}}, {"label": [14, 19], "documentation": {"kind": "markdown", "value": ""}}]
+    "parameters": [{"label": [0, 7], "documentation": {"kind": "markdown", "value": ""}}, {"label": [9, 12], "documentation": {"kind": "markdown", "value": ""}}, {"label": [14, 19], "documentation": {"kind": "markdown", "value": ""}}]
   }],
   "activeSignature": 0,
   "activeParameter": 0
@@ -183,11 +189,11 @@ ContextPath Value[otherFunc]
 Path otherFunc
 argAtCursor: unlabelled<2>
 extracted params: 
-[string, int, float]
+[(string, int, float]
 {
   "signatures": [{
     "label": "(string, int, float) => unit",
-    "parameters": [{"label": [1, 7], "documentation": {"kind": "markdown", "value": ""}}, {"label": [9, 12], "documentation": {"kind": "markdown", "value": ""}}, {"label": [14, 19], "documentation": {"kind": "markdown", "value": ""}}]
+    "parameters": [{"label": [0, 7], "documentation": {"kind": "markdown", "value": ""}}, {"label": [9, 12], "documentation": {"kind": "markdown", "value": ""}}, {"label": [14, 19], "documentation": {"kind": "markdown", "value": ""}}]
   }],
   "activeSignature": 0,
   "activeParameter": 2
@@ -204,11 +210,11 @@ ContextPath Value[Completion, Lib, foo]
 Path Completion.Lib.foo
 argAtCursor: ~age
 extracted params: 
-[~age: int, ~name: string]
+[(~age: int, ~name: string]
 {
   "signatures": [{
     "label": "(~age: int, ~name: string) => string",
-    "parameters": [{"label": [1, 10], "documentation": {"kind": "markdown", "value": ""}}, {"label": [12, 25], "documentation": {"kind": "markdown", "value": ""}}]
+    "parameters": [{"label": [0, 10], "documentation": {"kind": "markdown", "value": ""}}, {"label": [12, 25], "documentation": {"kind": "markdown", "value": ""}}]
   }],
   "activeSignature": 0,
   "activeParameter": 0
@@ -247,11 +253,11 @@ ContextPath Value[otherFunc]
 Path otherFunc
 argAtCursor: unlabelled<1>
 extracted params: 
-[string, int, float]
+[(string, int, float]
 {
   "signatures": [{
     "label": "(string, int, float) => unit",
-    "parameters": [{"label": [1, 7], "documentation": {"kind": "markdown", "value": ""}}, {"label": [9, 12], "documentation": {"kind": "markdown", "value": ""}}, {"label": [14, 19], "documentation": {"kind": "markdown", "value": ""}}]
+    "parameters": [{"label": [0, 7], "documentation": {"kind": "markdown", "value": ""}}, {"label": [9, 12], "documentation": {"kind": "markdown", "value": ""}}, {"label": [14, 19], "documentation": {"kind": "markdown", "value": ""}}]
   }],
   "activeSignature": 0,
   "activeParameter": 1
@@ -268,11 +274,11 @@ ContextPath Value[fn]
 Path fn
 argAtCursor: unlabelled<1>
 extracted params: 
-[int, string, int]
+[(int, string, int]
 {
   "signatures": [{
     "label": "(int, string, int) => unit",
-    "parameters": [{"label": [1, 4], "documentation": {"kind": "markdown", "value": ""}}, {"label": [6, 12], "documentation": {"kind": "markdown", "value": ""}}, {"label": [14, 17], "documentation": {"kind": "markdown", "value": ""}}]
+    "parameters": [{"label": [0, 4], "documentation": {"kind": "markdown", "value": ""}}, {"label": [6, 12], "documentation": {"kind": "markdown", "value": ""}}, {"label": [14, 17], "documentation": {"kind": "markdown", "value": ""}}]
   }],
   "activeSignature": 0,
   "activeParameter": 1
@@ -289,11 +295,11 @@ ContextPath Value[fn]
 Path fn
 argAtCursor: unlabelled<1>
 extracted params: 
-[int, string, int]
+[(int, string, int]
 {
   "signatures": [{
     "label": "(int, string, int) => unit",
-    "parameters": [{"label": [1, 4], "documentation": {"kind": "markdown", "value": ""}}, {"label": [6, 12], "documentation": {"kind": "markdown", "value": ""}}, {"label": [14, 17], "documentation": {"kind": "markdown", "value": ""}}]
+    "parameters": [{"label": [0, 4], "documentation": {"kind": "markdown", "value": ""}}, {"label": [6, 12], "documentation": {"kind": "markdown", "value": ""}}, {"label": [14, 17], "documentation": {"kind": "markdown", "value": ""}}]
   }],
   "activeSignature": 0,
   "activeParameter": 1
@@ -310,11 +316,11 @@ ContextPath Value[fn]
 Path fn
 argAtCursor: unlabelled<2>
 extracted params: 
-[int, string, int]
+[(int, string, int]
 {
   "signatures": [{
     "label": "(int, string, int) => unit",
-    "parameters": [{"label": [1, 4], "documentation": {"kind": "markdown", "value": ""}}, {"label": [6, 12], "documentation": {"kind": "markdown", "value": ""}}, {"label": [14, 17], "documentation": {"kind": "markdown", "value": ""}}]
+    "parameters": [{"label": [0, 4], "documentation": {"kind": "markdown", "value": ""}}, {"label": [6, 12], "documentation": {"kind": "markdown", "value": ""}}, {"label": [14, 17], "documentation": {"kind": "markdown", "value": ""}}]
   }],
   "activeSignature": 0,
   "activeParameter": 2
@@ -358,11 +364,12 @@ ContextPath Value[someFunc]
 Path someFunc
 argAtCursor: unlabelled<0>
 extracted params: 
-[int, ~two: string=?, ~three: unit => unit, ~four: someVariant, unit]
+[(
+  int, ~two: string=?, ~three: unit => unit, ~four: someVariant, unit]
 {
   "signatures": [{
     "label": "(\n  int,\n  ~two: string=?,\n  ~three: unit => unit,\n  ~four: someVariant,\n  unit,\n) => unit",
-    "parameters": [{"label": [4, 7], "documentation": {"kind": "markdown", "value": ""}}, {"label": [11, 25], "documentation": {"kind": "markdown", "value": ""}}, {"label": [29, 49], "documentation": {"kind": "markdown", "value": ""}}, {"label": [53, 71], "documentation": {"kind": "markdown", "value": "```rescript\ntype someVariant = One | Two | Three\n```\nGo to: [Type definition](command:rescript-vscode.go_to_location?%5B%22SignatureHelp.res%22%2C0%2C0%5D)"}}, {"label": [75, 79], "documentation": {"kind": "markdown", "value": ""}}],
+    "parameters": [{"label": [0, 7], "documentation": {"kind": "markdown", "value": ""}}, {"label": [11, 25], "documentation": {"kind": "markdown", "value": ""}}, {"label": [29, 49], "documentation": {"kind": "markdown", "value": ""}}, {"label": [53, 71], "documentation": {"kind": "markdown", "value": "```rescript\ntype someVariant = One | Two | Three\n```\nGo to: [Type definition](command:rescript-vscode.go_to_location?%5B%22SignatureHelp.res%22%2C0%2C0%5D)"}}, {"label": [75, 79], "documentation": {"kind": "markdown", "value": ""}}],
     "documentation": {"kind": "markdown", "value": " Does stuff. "}
   }],
   "activeSignature": 0,
@@ -449,11 +456,11 @@ Signature help src/SignatureHelp.res 105:9
 Signature help src/SignatureHelp.res 113:42
 argAtCursor: unlabelled<1>
 extracted params: 
-[array<int>, int => int]
+[(array<int>, int => int]
 {
   "signatures": [{
     "label": "(array<int>, int => int) => array<int>",
-    "parameters": [{"label": [1, 11], "documentation": {"kind": "markdown", "value": ""}}, {"label": [13, 23], "documentation": {"kind": "markdown", "value": ""}}],
+    "parameters": [{"label": [0, 11], "documentation": {"kind": "markdown", "value": ""}}, {"label": [13, 23], "documentation": {"kind": "markdown", "value": ""}}],
     "documentation": {"kind": "markdown", "value": "\n`map(array, fn)` returns a new array with all elements from `array`, each element transformed using the provided `fn`.\n\nSee [`Array.map`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/map) on MDN.\n\n## Examples\n```rescript\nlet array = [\"Hello\", \"Hi\", \"Good bye\"]\nlet mappedArray = array->Array.map(greeting => greeting ++ \" to you\")\n\nConsole.log(mappedArray) // [\"Hello to you\", \"Hi to you\", \"Good bye to you\"]\n```\n"}
   }],
   "activeSignature": 0,
@@ -463,11 +470,11 @@ extracted params:
 Signature help src/SignatureHelp.res 132:18
 argAtCursor: unlabelled<0>
 extracted params: 
-[x, tt]
+[(x, tt]
 {
   "signatures": [{
     "label": "(x, tt) => string",
-    "parameters": [{"label": [1, 2], "documentation": {"kind": "markdown", "value": "```rescript\ntype x = {age?: int, name?: string}\n```\nGo to: [Type definition](command:rescript-vscode.go_to_location?%5B%22SignatureHelp.res%22%2C117%2C0%5D)"}}, {"label": [4, 6], "documentation": {"kind": "markdown", "value": "```rescript\ntype tt = One\n```\nGo to: [Type definition](command:rescript-vscode.go_to_location?%5B%22SignatureHelp.res%22%2C123%2C0%5D)"}}],
+    "parameters": [{"label": [0, 2], "documentation": {"kind": "markdown", "value": "```rescript\ntype x = {age?: int, name?: string}\n```\nGo to: [Type definition](command:rescript-vscode.go_to_location?%5B%22SignatureHelp.res%22%2C117%2C0%5D)"}}, {"label": [4, 6], "documentation": {"kind": "markdown", "value": "```rescript\ntype tt = One\n```\nGo to: [Type definition](command:rescript-vscode.go_to_location?%5B%22SignatureHelp.res%22%2C123%2C0%5D)"}}],
     "documentation": {"kind": "markdown", "value": " Some stuff "}
   }],
   "activeSignature": 0,
@@ -477,11 +484,11 @@ extracted params:
 Signature help src/SignatureHelp.res 135:22
 argAtCursor: unlabelled<1>
 extracted params: 
-[x, tt]
+[(x, tt]
 {
   "signatures": [{
     "label": "(x, tt) => string",
-    "parameters": [{"label": [1, 2], "documentation": {"kind": "markdown", "value": "```rescript\ntype x = {age?: int, name?: string}\n```\nGo to: [Type definition](command:rescript-vscode.go_to_location?%5B%22SignatureHelp.res%22%2C117%2C0%5D)"}}, {"label": [4, 6], "documentation": {"kind": "markdown", "value": "```rescript\ntype tt = One\n```\nGo to: [Type definition](command:rescript-vscode.go_to_location?%5B%22SignatureHelp.res%22%2C123%2C0%5D)"}}],
+    "parameters": [{"label": [0, 2], "documentation": {"kind": "markdown", "value": "```rescript\ntype x = {age?: int, name?: string}\n```\nGo to: [Type definition](command:rescript-vscode.go_to_location?%5B%22SignatureHelp.res%22%2C117%2C0%5D)"}}, {"label": [4, 6], "documentation": {"kind": "markdown", "value": "```rescript\ntype tt = One\n```\nGo to: [Type definition](command:rescript-vscode.go_to_location?%5B%22SignatureHelp.res%22%2C123%2C0%5D)"}}],
     "documentation": {"kind": "markdown", "value": " Some stuff "}
   }],
   "activeSignature": 0,
diff --git a/tests/syntax_tests/data/parsing/errors/other/expected/labelledParameters.res.txt b/tests/syntax_tests/data/parsing/errors/other/expected/labelledParameters.res.txt
index e054529696..06b15e81f8 100644
--- a/tests/syntax_tests/data/parsing/errors/other/expected/labelledParameters.res.txt
+++ b/tests/syntax_tests/data/parsing/errors/other/expected/labelledParameters.res.txt
@@ -34,4 +34,4 @@
 let f [arity:3]x ?(y= 2)  z = (x + y) + z
 let g [arity:3]~x:((x)[@res.namedArgLoc ])  ?y:(((y)[@res.namedArgLoc ])= 2) 
   ~z:((z)[@res.namedArgLoc ])  = (x + y) + z
-type nonrec f = (x:int -> y:int -> int (a:2)) function$
\ No newline at end of file
+type nonrec f = x:int -> y:int -> int (a:2)
\ No newline at end of file
diff --git a/tests/syntax_tests/data/parsing/errors/other/expected/regionMissingComma.res.txt b/tests/syntax_tests/data/parsing/errors/other/expected/regionMissingComma.res.txt
index 40a466d444..8cc3ca5763 100644
--- a/tests/syntax_tests/data/parsing/errors/other/expected/regionMissingComma.res.txt
+++ b/tests/syntax_tests/data/parsing/errors/other/expected/regionMissingComma.res.txt
@@ -23,9 +23,9 @@
   Did you forget a `,` here?
 
 external make :
-  (?style:((ReactDOMRe.Style.t)[@res.namedArgLoc ]) ->
-     ?image:((bool)[@res.namedArgLoc ]) -> React.element (a:2))
-    function$ = "ModalContent"
+  ?style:((ReactDOMRe.Style.t)[@res.namedArgLoc ]) ->
+    ?image:((bool)[@res.namedArgLoc ]) -> React.element (a:2) =
+    "ModalContent"
 type nonrec 'extraInfo student =
   {
   name: string ;
diff --git a/tests/syntax_tests/data/parsing/errors/structure/expected/external.res.txt b/tests/syntax_tests/data/parsing/errors/structure/expected/external.res.txt
index aef3cb83a4..42d4421955 100644
--- a/tests/syntax_tests/data/parsing/errors/structure/expected/external.res.txt
+++ b/tests/syntax_tests/data/parsing/errors/structure/expected/external.res.txt
@@ -8,5 +8,4 @@
 
   An external requires the name of the JS value you're referring to, like "setTimeout".
 
-external setTimeout :
-  ((unit -> unit (a:1)) function$ -> int -> float (a:2)) function$
\ No newline at end of file
+external setTimeout : (unit -> unit (a:1)) -> int -> float (a:2)
\ No newline at end of file
diff --git a/tests/syntax_tests/data/parsing/errors/typeDef/expected/inlineRecord.res.txt b/tests/syntax_tests/data/parsing/errors/typeDef/expected/inlineRecord.res.txt
index 1b559e5e21..872b3da415 100644
--- a/tests/syntax_tests/data/parsing/errors/typeDef/expected/inlineRecord.res.txt
+++ b/tests/syntax_tests/data/parsing/errors/typeDef/expected/inlineRecord.res.txt
@@ -45,7 +45,5 @@ type nonrec user =
   address: < street: string  ;country: string   >  }
 let make
   [arity:1](props :
-             <
-               handleClick: (Click.t -> unit (a:1)) function$  ;value: 
-                                                                  string   > )
+             < handleClick: Click.t -> unit (a:1)  ;value: string   > )
   = render props
\ No newline at end of file
diff --git a/tests/syntax_tests/data/parsing/errors/typeDef/expected/namedParameters.res.txt b/tests/syntax_tests/data/parsing/errors/typeDef/expected/namedParameters.res.txt
index ded012ea92..b6b90fb587 100644
--- a/tests/syntax_tests/data/parsing/errors/typeDef/expected/namedParameters.res.txt
+++ b/tests/syntax_tests/data/parsing/errors/typeDef/expected/namedParameters.res.txt
@@ -7,4 +7,4 @@
 
   A labeled parameter starts with a `~`. Did you mean: `~stroke`?
 
-type nonrec draw = (stroke:pencil -> unit (a:1)) function$
\ No newline at end of file
+type nonrec draw = stroke:pencil -> unit (a:1)
\ No newline at end of file
diff --git a/tests/syntax_tests/data/parsing/errors/typeDef/expected/typeParams.res.txt b/tests/syntax_tests/data/parsing/errors/typeDef/expected/typeParams.res.txt
index 6c631c9719..c4024a1fac 100644
--- a/tests/syntax_tests/data/parsing/errors/typeDef/expected/typeParams.res.txt
+++ b/tests/syntax_tests/data/parsing/errors/typeDef/expected/typeParams.res.txt
@@ -62,16 +62,16 @@ type nonrec 'a node = {
 type nonrec ('from, 'for) derivedNode =
   {
   mutable value: 'to_ ;
-  updateF: ('from -> 'to_ (a:1)) function$ }
+  updateF: 'from -> 'to_ (a:1) }
 type nonrec ('from, ') derivedNode =
   {
   mutable value: 'to_ ;
-  updateF: ('from -> 'to_ (a:1)) function$ }
+  updateF: 'from -> 'to_ (a:1) }
 type nonrec ('from, ') derivedNode =
   {
   mutable value: 'to_ ;
-  updateF: ('from -> 'to_ (a:1)) function$ }
+  updateF: 'from -> 'to_ (a:1) }
 type nonrec ('from, 'foo) derivedNode =
   {
   mutable value: 'to_ ;
-  updateF: ('from -> 'to_ (a:1)) function$ }
\ No newline at end of file
+  updateF: 'from -> 'to_ (a:1) }
\ No newline at end of file
diff --git a/tests/syntax_tests/data/parsing/errors/typexpr/expected/arrow.res.txt b/tests/syntax_tests/data/parsing/errors/typexpr/expected/arrow.res.txt
index e5ccd919a6..4a76a16f95 100644
--- a/tests/syntax_tests/data/parsing/errors/typexpr/expected/arrow.res.txt
+++ b/tests/syntax_tests/data/parsing/errors/typexpr/expected/arrow.res.txt
@@ -33,16 +33,15 @@
 
   Did you forget a `:` here? It signals the start of a type
 
-external add_nat : (nat -> int (a:1)) function$ = "add_nat_bytecode"
+external add_nat : nat -> int (a:1) = "add_nat_bytecode"
 module Error2 =
   struct
     type nonrec observation =
       {
       observed: int ;
       onStep:
-        (currentValue:((unit)[@res.namedArgLoc ]) ->
-           [%rescript.typehole ] (a:1))
-          function$
+        currentValue:((unit)[@res.namedArgLoc ]) ->
+          [%rescript.typehole ] (a:1)
         }
   end
 module Error3 =
diff --git a/tests/syntax_tests/data/parsing/errors/typexpr/expected/bsObjSugar.res.txt b/tests/syntax_tests/data/parsing/errors/typexpr/expected/bsObjSugar.res.txt
index dfe23855db..ebb718e555 100644
--- a/tests/syntax_tests/data/parsing/errors/typexpr/expected/bsObjSugar.res.txt
+++ b/tests/syntax_tests/data/parsing/errors/typexpr/expected/bsObjSugar.res.txt
@@ -142,7 +142,7 @@ type nonrec state =
     > 
 type nonrec state = < url: string  ;protocols: [%rescript.typehole ]   > 
 type nonrec state =
-  < send: (string -> [%rescript.typehole ] (a:1)) function$ [@meth ]  > 
+  < send: string -> [%rescript.typehole ] (a:1) [@meth ]  > 
 type nonrec state = < age: [%rescript.typehole ]  ;name: string   > 
 type nonrec state = < age: [%rescript.typehole ] [@set ] ;name: string   > 
 type nonrec state = < age: [%rescript.typehole ]   ;.. > 
diff --git a/tests/syntax_tests/data/parsing/errors/typexpr/expected/garbage.res.txt b/tests/syntax_tests/data/parsing/errors/typexpr/expected/garbage.res.txt
index a4e8c44541..bce429c7f3 100644
--- a/tests/syntax_tests/data/parsing/errors/typexpr/expected/garbage.res.txt
+++ b/tests/syntax_tests/data/parsing/errors/typexpr/expected/garbage.res.txt
@@ -9,5 +9,5 @@
   I'm not sure what to parse here when looking at "?".
 
 external printName :
-  (name:((unit)[@res.namedArgLoc ]) -> unit (a:1)) function$ = "printName"
-[@@module {js|moduleName|js}]
\ No newline at end of file
+  name:((unit)[@res.namedArgLoc ]) -> unit (a:1) = "printName"[@@module
+                                                                {js|moduleName|js}]
\ No newline at end of file
diff --git a/tests/syntax_tests/data/parsing/grammar/expressions/expected/UncurriedByDefault.res.txt b/tests/syntax_tests/data/parsing/grammar/expressions/expected/UncurriedByDefault.res.txt
index 679e19d559..873c89937e 100644
--- a/tests/syntax_tests/data/parsing/grammar/expressions/expected/UncurriedByDefault.res.txt
+++ b/tests/syntax_tests/data/parsing/grammar/expressions/expected/UncurriedByDefault.res.txt
@@ -6,42 +6,36 @@ let mixFun [arity:3]a b c [arity:3]d e f [arity:2]g h = 4
 let bracesFun [arity:1]x [arity:1]y = x + y
 let cFun2 [arity:2]x y = 3
 let uFun2 [arity:2]x y = 3
-type nonrec cTyp = (string -> int (a:1)) function$
-type nonrec uTyp = (string -> int (a:1)) function$
+type nonrec cTyp = string -> int (a:1)
+type nonrec uTyp = string -> int (a:1)
 type nonrec mixTyp =
-  (string ->
-     string ->
-       string ->
-         (string ->
-            string -> string -> (string -> string -> int (a:2)) function$ (a:3))
-           function$ (a:3))
-    function$
-type nonrec bTyp =
-  (string -> (string -> int (a:1)) function$ (a:1)) function$
-type nonrec cTyp2 = (string -> string -> int (a:2)) function$
-type nonrec uTyp2 = (string -> string -> int (a:2)) function$
-type nonrec cu = (unit -> int (a:1)) function$
-type nonrec cp = (unit -> int (a:1)) function$
-type nonrec cuu = (unit -> (unit -> int (a:1)) function$ (a:1)) function$
-type nonrec cpu = (unit -> (unit -> int (a:1)) function$ (a:1)) function$
-type nonrec cup = (unit -> (unit -> int (a:1)) function$ (a:1)) function$
-type nonrec cpp = (unit -> (unit -> int (a:1)) function$ (a:1)) function$
-type nonrec cu2 = (unit -> unit -> unit (a:2)) function$
-type nonrec cp2 = (unit -> unit -> unit (a:2)) function$
-type nonrec uu = (unit -> int (a:1)) function$
-type nonrec up = (unit -> int (a:1)) function$
-type nonrec uuu = (unit -> (unit -> int (a:1)) function$ (a:1)) function$
-type nonrec upu = (unit -> (unit -> int (a:1)) function$ (a:1)) function$
-type nonrec uup = (unit -> (unit -> int (a:1)) function$ (a:1)) function$
-type nonrec upp = (unit -> (unit -> int (a:1)) function$ (a:1)) function$
-type nonrec uu2 = (unit -> unit -> unit (a:2)) function$
-type nonrec up2 = (unit -> unit -> unit (a:2)) function$
-type nonrec cnested =
-  ((string -> unit (a:1)) function$ -> unit (a:1)) function$
-type nonrec unested =
-  ((string -> unit (a:1)) function$ -> unit (a:1)) function$
-let (uannpoly : ('a -> string (a:1)) function$) = xx
-let (uannint : (int -> string (a:1)) function$) = xx
+  string ->
+    string ->
+      string ->
+        string -> string -> string -> string -> string -> int (a:2) (a:3) (a:3)
+type nonrec bTyp = string -> string -> int (a:1) (a:1)
+type nonrec cTyp2 = string -> string -> int (a:2)
+type nonrec uTyp2 = string -> string -> int (a:2)
+type nonrec cu = unit -> int (a:1)
+type nonrec cp = unit -> int (a:1)
+type nonrec cuu = unit -> unit -> int (a:1) (a:1)
+type nonrec cpu = unit -> unit -> int (a:1) (a:1)
+type nonrec cup = unit -> unit -> int (a:1) (a:1)
+type nonrec cpp = unit -> unit -> int (a:1) (a:1)
+type nonrec cu2 = unit -> unit -> unit (a:2)
+type nonrec cp2 = unit -> unit -> unit (a:2)
+type nonrec uu = unit -> int (a:1)
+type nonrec up = unit -> int (a:1)
+type nonrec uuu = unit -> unit -> int (a:1) (a:1)
+type nonrec upu = unit -> unit -> int (a:1) (a:1)
+type nonrec uup = unit -> unit -> int (a:1) (a:1)
+type nonrec upp = unit -> unit -> int (a:1) (a:1)
+type nonrec uu2 = unit -> unit -> unit (a:2)
+type nonrec up2 = unit -> unit -> unit (a:2)
+type nonrec cnested = (string -> unit (a:1)) -> unit (a:1)
+type nonrec unested = (string -> unit (a:1)) -> unit (a:1)
+let (uannpoly : 'a -> string (a:1)) = xx
+let (uannint : int -> string (a:1)) = xx
 let _ = ((fun [arity:1]x -> 34)[@att ])
 let _ = ((fun [arity:1]x -> 34)[@res.async ][@att ])
 let _ = preserveAttr ((fun [arity:1]x -> 34)[@att ])
@@ -53,15 +47,13 @@ let t3 (type a) (type b) [arity:2](l : a list) (x : a) = x :: l
 let t4 (type a) (type b) [arity:2](l : a list) (x : a) = x :: l
 let t5 (type a) (type b) [arity:2](l : a list) (x : a) = x :: l
 let t6 (type a) (type b) [arity:2](l : a list) (x : a) = x :: l
-type nonrec arrowPath1 = (int -> string (a:1)) function$
-type nonrec arrowPath2 = (I.t -> string (a:1)) function$
-type nonrec arrowPath3 = (int -> string (a:1)) function$
-type nonrec arrowPath4 = (I.t -> string (a:1)) function$
-type nonrec callback1 =
-  (ReactEvent.Mouse.t -> unit (a:1)) function$ as 'callback
-type nonrec callback2 = (ReactEvent.Mouse.t -> unit as 'u (a:1)) function$
-type nonrec callback3 =
-  (ReactEvent.Mouse.t -> unit (a:1)) function$ as 'callback
+type nonrec arrowPath1 = int -> string (a:1)
+type nonrec arrowPath2 = I.t -> string (a:1)
+type nonrec arrowPath3 = int -> string (a:1)
+type nonrec arrowPath4 = I.t -> string (a:1)
+type nonrec callback1 = (ReactEvent.Mouse.t -> unit (a:1)) as 'callback
+type nonrec callback2 = ReactEvent.Mouse.t -> unit as 'u (a:1)
+type nonrec callback3 = (ReactEvent.Mouse.t -> unit (a:1)) as 'callback
 let cApp = foo 3
 let uApp = foo 3
 let cFun [arity:1]x = 3
@@ -71,44 +63,37 @@ let bracesFun [arity:1]x [arity:1]y = x + y
 let cFun2 [arity:2]x y = 3
 let uFun2 [arity:2]x y = 3
 let cFun2Dots [arity:2]x y = 3
-type nonrec cTyp = (string -> int (a:1)) function$
-type nonrec uTyp = (string -> int (a:1)) function$
+type nonrec cTyp = string -> int (a:1)
+type nonrec uTyp = string -> int (a:1)
 type nonrec mixTyp =
-  (string ->
-     (string ->
-        string ->
-          (string ->
-             string -> string -> string -> (string -> int (a:1)) function$ (a:4))
-            function$ (a:2))
-       function$ (a:1))
-    function$
-type nonrec bTyp =
-  (string -> (string -> int (a:1)) function$ (a:1)) function$
-type nonrec cTyp2 = (string -> string -> int (a:2)) function$
-type nonrec uTyp2 = (string -> string -> int (a:2)) function$
-type nonrec cu = (unit -> int (a:1)) function$
-type nonrec cp = (unit -> int (a:1)) function$
-type nonrec cuu = (unit -> (unit -> int (a:1)) function$ (a:1)) function$
-type nonrec cpu = (unit -> (unit -> int (a:1)) function$ (a:1)) function$
-type nonrec cup = (unit -> (unit -> int (a:1)) function$ (a:1)) function$
-type nonrec cpp = (unit -> (unit -> int (a:1)) function$ (a:1)) function$
-type nonrec cu2 = (unit -> unit -> unit (a:2)) function$
-type nonrec cp2 = (unit -> unit -> unit (a:2)) function$
-type nonrec uu = (unit -> int (a:1)) function$
-type nonrec up = (unit -> int (a:1)) function$
-type nonrec uuu = (unit -> (unit -> int (a:1)) function$ (a:1)) function$
-type nonrec upu = (unit -> (unit -> int (a:1)) function$ (a:1)) function$
-type nonrec uup = (unit -> (unit -> int (a:1)) function$ (a:1)) function$
-type nonrec upp = (unit -> (unit -> int (a:1)) function$ (a:1)) function$
-type nonrec uu2 = (unit -> unit -> unit (a:2)) function$
-type nonrec up2 = (unit -> unit -> unit (a:2)) function$
-type nonrec cnested =
-  ((string -> unit (a:1)) function$ -> unit (a:1)) function$
-type nonrec unested =
-  ((string -> unit (a:1)) function$ -> unit (a:1)) function$
+  string ->
+    string ->
+      string ->
+        string -> string -> string -> string -> string -> int (a:1) (a:4) (a:2) (a:1)
+type nonrec bTyp = string -> string -> int (a:1) (a:1)
+type nonrec cTyp2 = string -> string -> int (a:2)
+type nonrec uTyp2 = string -> string -> int (a:2)
+type nonrec cu = unit -> int (a:1)
+type nonrec cp = unit -> int (a:1)
+type nonrec cuu = unit -> unit -> int (a:1) (a:1)
+type nonrec cpu = unit -> unit -> int (a:1) (a:1)
+type nonrec cup = unit -> unit -> int (a:1) (a:1)
+type nonrec cpp = unit -> unit -> int (a:1) (a:1)
+type nonrec cu2 = unit -> unit -> unit (a:2)
+type nonrec cp2 = unit -> unit -> unit (a:2)
+type nonrec uu = unit -> int (a:1)
+type nonrec up = unit -> int (a:1)
+type nonrec uuu = unit -> unit -> int (a:1) (a:1)
+type nonrec upu = unit -> unit -> int (a:1) (a:1)
+type nonrec uup = unit -> unit -> int (a:1) (a:1)
+type nonrec upp = unit -> unit -> int (a:1) (a:1)
+type nonrec uu2 = unit -> unit -> unit (a:2)
+type nonrec up2 = unit -> unit -> unit (a:2)
+type nonrec cnested = (string -> unit (a:1)) -> unit (a:1)
+type nonrec unested = (string -> unit (a:1)) -> unit (a:1)
 let pipe1 = 3 |.u f
-let (uannpoly : ('a -> string (a:1)) function$) = xx
-let (uannint : (int -> string (a:1)) function$) = xx
+let (uannpoly : 'a -> string (a:1)) = xx
+let (uannint : int -> string (a:1)) = xx
 let _ = ((fun [arity:1]x -> 34)[@att ])
 let _ = ((fun [arity:1]x -> 34)[@res.async ][@att ])
 let _ = preserveAttr ((fun [arity:1]x -> 34)[@att ])
@@ -117,12 +102,10 @@ let t0 (type a) (type b) [arity:2](l : a list) (x : a) = x :: l
 let t1 (type a) (type b) [arity:2](l : a list) (x : a) = x :: l
 let t2 (type a) (type b) [arity:2](l : a list) (x : a) = x :: l
 let t3 (type a) (type b) [arity:2](l : a list) (x : a) = x :: l
-type nonrec arrowPath1 = (int -> string (a:1)) function$
-type nonrec arrowPath2 = (I.t -> string (a:1)) function$
-type nonrec arrowPath3 = (int -> string (a:1)) function$
-type nonrec arrowPath4 = (I.t -> string (a:1)) function$
-type nonrec callback1 =
-  (ReactEvent.Mouse.t -> unit (a:1)) function$ as 'callback
-type nonrec callback2 = (ReactEvent.Mouse.t -> unit as 'u (a:1)) function$
-type nonrec callback3 =
-  (ReactEvent.Mouse.t -> unit (a:1)) function$ as 'callback
\ No newline at end of file
+type nonrec arrowPath1 = int -> string (a:1)
+type nonrec arrowPath2 = I.t -> string (a:1)
+type nonrec arrowPath3 = int -> string (a:1)
+type nonrec arrowPath4 = I.t -> string (a:1)
+type nonrec callback1 = (ReactEvent.Mouse.t -> unit (a:1)) as 'callback
+type nonrec callback2 = ReactEvent.Mouse.t -> unit as 'u (a:1)
+type nonrec callback3 = (ReactEvent.Mouse.t -> unit (a:1)) as 'callback
\ No newline at end of file
diff --git a/tests/syntax_tests/data/parsing/grammar/expressions/expected/arrow.res.txt b/tests/syntax_tests/data/parsing/grammar/expressions/expected/arrow.res.txt
index eef2983731..08267a2656 100644
--- a/tests/syntax_tests/data/parsing/grammar/expressions/expected/arrow.res.txt
+++ b/tests/syntax_tests/data/parsing/grammar/expressions/expected/arrow.res.txt
@@ -83,5 +83,5 @@ let un = (() : u)
 type nonrec ('a, 'b) d = ('a * 'b)
 let c [arity:1]() = ((1, 2) : ('a, 'b) d)
 let fn [arity:1]f = f
-type nonrec f = (int -> unit (a:1)) function$
+type nonrec f = int -> unit (a:1)
 let a = fn (fun [arity:1]_ -> () : f)
\ No newline at end of file
diff --git a/tests/syntax_tests/data/parsing/grammar/expressions/expected/block.res.txt b/tests/syntax_tests/data/parsing/grammar/expressions/expected/block.res.txt
index 9035f13ee8..4c6941882b 100644
--- a/tests/syntax_tests/data/parsing/grammar/expressions/expected/block.res.txt
+++ b/tests/syntax_tests/data/parsing/grammar/expressions/expected/block.res.txt
@@ -53,8 +53,7 @@ let reifyStyle (type a) [arity:1](x : 'a) =
          let instanceOf =
            ([%raw
               (({js|function(x,y) {return +(x instanceof y)}|js})
-                [@res.template ])] : ('a -> constructor -> bool (a:2))
-                                       function$)
+                [@res.template ])] : 'a -> constructor -> bool (a:2))
        end in
        ((if (Js.typeof x) = {js|string|js}
          then Obj.magic String
diff --git a/tests/syntax_tests/data/parsing/grammar/expressions/expected/locallyAbstractTypes.res.txt b/tests/syntax_tests/data/parsing/grammar/expressions/expected/locallyAbstractTypes.res.txt
index 132e76632f..21ac8611c1 100644
--- a/tests/syntax_tests/data/parsing/grammar/expressions/expected/locallyAbstractTypes.res.txt
+++ b/tests/syntax_tests/data/parsing/grammar/expressions/expected/locallyAbstractTypes.res.txt
@@ -13,8 +13,7 @@ let f = ((fun (type t) -> ((fun (type s) ->
   [@attr ]))[@attr ])
 let cancel_and_collect_callbacks :
   'a 'u 'c .
-    (packed_callbacks list ->
-       ('a, 'u, 'c) promise -> packed_callbacks list (a:2))
-      function$
+    packed_callbacks list ->
+      ('a, 'u, 'c) promise -> packed_callbacks list (a:2)
   = fun (type x) ->
   fun [arity:2]callbacks_accumulator -> fun (p : (_, _, c) promise) -> ()
\ No newline at end of file
diff --git a/tests/syntax_tests/data/parsing/grammar/modexpr/expected/functor.res.txt b/tests/syntax_tests/data/parsing/grammar/modexpr/expected/functor.res.txt
index 8e18c0f55b..834302dc14 100644
--- a/tests/syntax_tests/data/parsing/grammar/modexpr/expected/functor.res.txt
+++ b/tests/syntax_tests/data/parsing/grammar/modexpr/expected/functor.res.txt
@@ -14,13 +14,12 @@ module F() = Map
 module F = ((functor () -> Map)[@functorAttr ])
 include functor () -> Map
 include ((functor () -> Map)[@functorAttr ])
-module Make(Cmp:sig type nonrec t val eq : (t -> t -> bool (a:2)) function$
-                end) :
+module Make(Cmp:sig type nonrec t val eq : t -> t -> bool (a:2) end) :
   sig
     type nonrec key = Cmp.t
     type nonrec coll
     val empty : coll
-    val add : (coll -> key -> coll (a:2)) function$
+    val add : coll -> key -> coll (a:2)
   end =
   struct
     open Cmp
diff --git a/tests/syntax_tests/data/parsing/grammar/modtype/expected/parenthesized.res.txt b/tests/syntax_tests/data/parsing/grammar/modtype/expected/parenthesized.res.txt
index 051ed166ba..7a409bd420 100644
--- a/tests/syntax_tests/data/parsing/grammar/modtype/expected/parenthesized.res.txt
+++ b/tests/syntax_tests/data/parsing/grammar/modtype/expected/parenthesized.res.txt
@@ -4,11 +4,11 @@ module type Bt  = ((Btree)[@attrIdent ][@attrParens ])
 module type MyHash  =
   sig
     include module type of struct include Hashtbl end
-    val replace : (('a, 'b) t -> 'a -> 'b -> unit (a:3)) function$
+    val replace : ('a, 'b) t -> 'a -> 'b -> unit (a:3)
   end
 module type MyHash  =
   sig
     include
       ((module type of struct include Hashtbl end)[@onModTypeOf ][@onParens ])
-    val replace : (('a, 'b) t -> 'a -> 'b -> unit (a:3)) function$
+    val replace : ('a, 'b) t -> 'a -> 'b -> unit (a:3)
   end
\ No newline at end of file
diff --git a/tests/syntax_tests/data/parsing/grammar/modtype/expected/typeof.res.txt b/tests/syntax_tests/data/parsing/grammar/modtype/expected/typeof.res.txt
index 616d14735d..7cf210a905 100644
--- a/tests/syntax_tests/data/parsing/grammar/modtype/expected/typeof.res.txt
+++ b/tests/syntax_tests/data/parsing/grammar/modtype/expected/typeof.res.txt
@@ -1,10 +1,10 @@
 module type MyHash  =
   sig
     include module type of struct include Hashtbl end
-    val replace : (('a, 'b) t -> 'a -> 'b -> unit (a:3)) function$
+    val replace : ('a, 'b) t -> 'a -> 'b -> unit (a:3)
   end
 module type MyHash  =
   sig
     include ((module type of struct include Hashtbl end)[@onModuleTypeOf ])
-    val replace : (('a, 'b) t -> 'a -> 'b -> unit (a:3)) function$
+    val replace : ('a, 'b) t -> 'a -> 'b -> unit (a:3)
   end
\ No newline at end of file
diff --git a/tests/syntax_tests/data/parsing/grammar/modtype/expected/with.res.txt b/tests/syntax_tests/data/parsing/grammar/modtype/expected/with.res.txt
index e139cf5be9..24bd049351 100644
--- a/tests/syntax_tests/data/parsing/grammar/modtype/expected/with.res.txt
+++ b/tests/syntax_tests/data/parsing/grammar/modtype/expected/with.res.txt
@@ -29,11 +29,8 @@ module type A  =
   (Foo with module X.Bar := Belt.Array and module X.Bar := Belt.Array and
     module X.Bar := Belt.Array)
 module type Printable  =
-  sig
-    type nonrec t
-    val print : (Format.formatter -> t -> unit (a:2)) function$
-  end
+  sig type nonrec t val print : Format.formatter -> t -> unit (a:2) end
 module type Comparable  =
-  sig type nonrec t val compare : (t -> t -> int (a:2)) function$ end
+  sig type nonrec t val compare : t -> t -> int (a:2) end
 module type PrintableComparable  =
   sig include Printable include (Comparable with type  t :=  t) end
\ No newline at end of file
diff --git a/tests/syntax_tests/data/parsing/grammar/signature/expected/external.res.txt b/tests/syntax_tests/data/parsing/grammar/signature/expected/external.res.txt
index fdd4cf2d6f..196499d2a1 100644
--- a/tests/syntax_tests/data/parsing/grammar/signature/expected/external.res.txt
+++ b/tests/syntax_tests/data/parsing/grammar/signature/expected/external.res.txt
@@ -2,10 +2,9 @@ module type Signature  =
   sig
     type nonrec t
     external linkProgram :
-      (t -> program:((webGlProgram)[@res.namedArgLoc ]) -> unit (a:2))
-        function$ = "linkProgram"[@@send ]
-    external add_nat :
-      (nat -> int -> int -> int (a:3)) function$ = "add_nat_bytecode"
-    external svg : (unit -> React.element (a:1)) function$ = "svg"
-    external svg : (unit -> React.element (a:1)) function$ = "svg"
+      t -> program:((webGlProgram)[@res.namedArgLoc ]) -> unit (a:2) =
+        "linkProgram"[@@send ]
+    external add_nat : nat -> int -> int -> int (a:3) = "add_nat_bytecode"
+    external svg : unit -> React.element (a:1) = "svg"
+    external svg : unit -> React.element (a:1) = "svg"
   end
\ No newline at end of file
diff --git a/tests/syntax_tests/data/parsing/grammar/signature/expected/recModule.res.txt b/tests/syntax_tests/data/parsing/grammar/signature/expected/recModule.res.txt
index 189a6fdf7a..07e1700d8c 100644
--- a/tests/syntax_tests/data/parsing/grammar/signature/expected/recModule.res.txt
+++ b/tests/syntax_tests/data/parsing/grammar/signature/expected/recModule.res.txt
@@ -5,7 +5,7 @@ module type Signature  =
         type nonrec t =
           | Leaf of string 
           | Node of ASet.t 
-        val compare : (t -> t -> int (a:2)) function$
+        val compare : t -> t -> int (a:2)
       end
     and ASet: (Set.S with type  elt =  A.t)
     and BTree: (Btree.S with type  elt =  A.t)
@@ -14,7 +14,7 @@ module type Signature  =
         type nonrec t =
           | Leaf of string 
           | Node of ASet.t 
-        val compare : (t -> t -> int (a:2)) function$
+        val compare : t -> t -> int (a:2)
       end[@@onFirstAttr ]
     and ASet: (Set.S with type  elt =  A.t)[@@onSecondAttr ]
     module rec A: Btree[@@parsableOnNext ]
diff --git a/tests/syntax_tests/data/parsing/grammar/structure/expected/externalDefinition.res.txt b/tests/syntax_tests/data/parsing/grammar/structure/expected/externalDefinition.res.txt
index f711d90b41..94f22ade32 100644
--- a/tests/syntax_tests/data/parsing/grammar/structure/expected/externalDefinition.res.txt
+++ b/tests/syntax_tests/data/parsing/grammar/structure/expected/externalDefinition.res.txt
@@ -1,12 +1,11 @@
-external clear : (t -> int -> unit (a:2)) function$ = "clear"
-external add_nat : (nat -> int (a:1)) function$ = "add_nat_bytecode"
+external clear : t -> int -> unit (a:2) = "clear"
+external add_nat : nat -> int (a:1) = "add_nat_bytecode"
 external attachShader :
-  (t ->
-     program:((webGlProgram)[@res.namedArgLoc ]) ->
-       shader:((webGlShader)[@res.namedArgLoc ]) -> unit (a:3))
-    function$ = "attachShader"[@@send ]
-external svg : (unit -> React.element (a:1)) function$ = "svg"
-external svg : (unit -> React.element (a:1)) function$ = "svg"
-external createDate : (unit -> unit -> date (a:2)) function$ = "Date"
-[@@new ]
+  t ->
+    program:((webGlProgram)[@res.namedArgLoc ]) ->
+      shader:((webGlShader)[@res.namedArgLoc ]) -> unit (a:3) =
+    "attachShader"[@@send ]
+external svg : unit -> React.element (a:1) = "svg"
+external svg : unit -> React.element (a:1) = "svg"
+external createDate : unit -> unit -> date (a:2) = "Date"[@@new ]
 let foobar = (createDate ()) ()
\ No newline at end of file
diff --git a/tests/syntax_tests/data/parsing/grammar/typedefinition/expected/constructorDeclaration.res.txt b/tests/syntax_tests/data/parsing/grammar/typedefinition/expected/constructorDeclaration.res.txt
index 7cc204d5cf..e2396030d8 100644
--- a/tests/syntax_tests/data/parsing/grammar/typedefinition/expected/constructorDeclaration.res.txt
+++ b/tests/syntax_tests/data/parsing/grammar/typedefinition/expected/constructorDeclaration.res.txt
@@ -83,11 +83,11 @@ type nonrec (_, 'value) node =
   mutable cachedValue: 'value ;
   parent: (_, 'value) node ;
   root: (root, 'value) node ;
-  updateF: ('value -> 'value (a:1)) function$ ;
+  updateF: 'value -> 'value (a:1) ;
   mutable updatedTime: float } -> (derived, 'value) node 
 type nonrec delta =
-  | Compute of (< blocked_ids: unit   >  -> unit (a:1)) function$ 
+  | Compute of (< blocked_ids: unit   >  -> unit (a:1)) 
 type nonrec queryDelta =
-  | Compute of (< blocked_ids: unit   >  -> unit (a:1)) function$ 
-  | Compute of (< blocked_ids: unit   >  -> unit (a:1)) function$ *
-  (< allowed_ids: unit   >  -> unit (a:1)) function$ 
\ No newline at end of file
+  | Compute of (< blocked_ids: unit   >  -> unit (a:1)) 
+  | Compute of (< blocked_ids: unit   >  -> unit (a:1)) *
+  (< allowed_ids: unit   >  -> unit (a:1)) 
\ No newline at end of file
diff --git a/tests/syntax_tests/data/parsing/grammar/typedefinition/expected/privateTypeEquation.res.txt b/tests/syntax_tests/data/parsing/grammar/typedefinition/expected/privateTypeEquation.res.txt
index 92f00566f2..1bc71f372b 100644
--- a/tests/syntax_tests/data/parsing/grammar/typedefinition/expected/privateTypeEquation.res.txt
+++ b/tests/syntax_tests/data/parsing/grammar/typedefinition/expected/privateTypeEquation.res.txt
@@ -2,11 +2,11 @@ type nonrec t = private 'a
 type nonrec t = private string
 type nonrec t = private _
 type nonrec t = private int
-type nonrec t = private (int -> int (a:1)) function$
-type nonrec t = private (int -> int (a:1)) function$
-type nonrec t = private (int -> (int -> int (a:1)) function$ (a:1)) function$
+type nonrec t = private int -> int (a:1)
+type nonrec t = private int -> int (a:1)
+type nonrec t = private int -> int -> int (a:1) (a:1)
 type nonrec t = private
-  (int -> x:((string)[@res.namedArgLoc ]) -> float -> unit (a:3)) function$
+  int -> x:((string)[@res.namedArgLoc ]) -> float -> unit (a:3)
 type nonrec t = private string as 'x
 type nonrec t = private [%ext ]
 type nonrec t = private [%ext {js|console.log|js}]
diff --git a/tests/syntax_tests/data/parsing/grammar/typedefinition/expected/typeInformation.res.txt b/tests/syntax_tests/data/parsing/grammar/typedefinition/expected/typeInformation.res.txt
index b802141178..82373a51cd 100644
--- a/tests/syntax_tests/data/parsing/grammar/typedefinition/expected/typeInformation.res.txt
+++ b/tests/syntax_tests/data/parsing/grammar/typedefinition/expected/typeInformation.res.txt
@@ -70,8 +70,6 @@ type nonrec t = private
 type nonrec t = {
   x: int ;
   y: int }
-type nonrec callback =
-  (ReactEvent.Mouse.t -> unit (a:1)) function$ as 'callback
-type nonrec callback = (ReactEvent.Mouse.t -> unit as 'u (a:1)) function$
-type nonrec callback =
-  (ReactEvent.Mouse.t -> unit (a:1)) function$ as 'callback
\ No newline at end of file
+type nonrec callback = (ReactEvent.Mouse.t -> unit (a:1)) as 'callback
+type nonrec callback = ReactEvent.Mouse.t -> unit as 'u (a:1)
+type nonrec callback = (ReactEvent.Mouse.t -> unit (a:1)) as 'callback
\ No newline at end of file
diff --git a/tests/syntax_tests/data/parsing/grammar/typexpr/expected/alias.res.txt b/tests/syntax_tests/data/parsing/grammar/typexpr/expected/alias.res.txt
index b5d5ea85e6..5c9e904bf5 100644
--- a/tests/syntax_tests/data/parsing/grammar/typexpr/expected/alias.res.txt
+++ b/tests/syntax_tests/data/parsing/grammar/typexpr/expected/alias.res.txt
@@ -1,10 +1,10 @@
 type nonrec t = string as 's
 type nonrec t = _ as 'underscore
 type nonrec t = parenthesizedType as 'parens
-type nonrec t = (int -> unit (a:1)) function$ as 'arrow
-type nonrec t = (int -> unit as 'unitAlias (a:1)) function$
-type nonrec t = (int -> float -> unit (a:2)) function$ as 'arrowAlias
-type nonrec t = (int -> float -> unit as 'unitAlias (a:2)) function$
+type nonrec t = (int -> unit (a:1)) as 'arrow
+type nonrec t = int -> unit as 'unitAlias (a:1)
+type nonrec t = (int -> float -> unit (a:2)) as 'arrowAlias
+type nonrec t = int -> float -> unit as 'unitAlias (a:2)
 type nonrec t = int as 'myNumber
 type nonrec t = Mod.Sub.t as 'longidentAlias
 type nonrec t = (int as 'r, int as 'g, int as 'b) color as 'rgb
@@ -16,10 +16,10 @@ type nonrec tup = ((int as 'x) * (int as 'y)) as 'tupleAlias
 let (t : string as 's) = ()
 let (t : _ as 'underscore) = ()
 let (t : parenthesizedType as 'parens) = ()
-let (t : (int -> unit (a:1)) function$ as 'arrow) = ()
-let (t : (int -> unit as 'unitAlias (a:1)) function$) = ()
-let (t : (int -> float -> unit (a:2)) function$ as 'arrowAlias) = ()
-let (t : (int -> float -> unit as 'unitAlias (a:2)) function$) = ()
+let (t : (int -> unit (a:1)) as 'arrow) = ()
+let (t : int -> unit as 'unitAlias (a:1)) = ()
+let (t : (int -> float -> unit (a:2)) as 'arrowAlias) = ()
+let (t : int -> float -> unit as 'unitAlias (a:2)) = ()
 let (t : int as 'myNumber) = ()
 let (t : Mod.Sub.t as 'longidentAlias) = ()
 let (t : (int as 'r, int as 'g, int as 'b) color as 'rgb) = ()
diff --git a/tests/syntax_tests/data/parsing/grammar/typexpr/expected/es6Arrow.res.txt b/tests/syntax_tests/data/parsing/grammar/typexpr/expected/es6Arrow.res.txt
index 4320d463c7..1caf71d444 100644
--- a/tests/syntax_tests/data/parsing/grammar/typexpr/expected/es6Arrow.res.txt
+++ b/tests/syntax_tests/data/parsing/grammar/typexpr/expected/es6Arrow.res.txt
@@ -1,71 +1,49 @@
-type nonrec t = (x -> unit (a:1)) function$
-type nonrec t = (x -> unit (a:1)) function$
-type nonrec t = (int -> string -> unit (a:2)) function$
+type nonrec t = x -> unit (a:1)
+type nonrec t = x -> unit (a:1)
+type nonrec t = int -> string -> unit (a:2)
 type nonrec t =
-  (a:((int)[@res.namedArgLoc ]) -> b:((int)[@res.namedArgLoc ]) -> int (a:2))
-    function$
+  a:((int)[@res.namedArgLoc ]) -> b:((int)[@res.namedArgLoc ]) -> int (a:2)
 type nonrec t =
-  (?a:((int)[@res.namedArgLoc ]) ->
-     ?b:((int)[@res.namedArgLoc ]) -> int (a:2))
-    function$
+  ?a:((int)[@res.namedArgLoc ]) -> ?b:((int)[@res.namedArgLoc ]) -> int (a:2)
+type nonrec t = int -> int -> int -> int (a:1) (a:1) (a:1)
 type nonrec t =
-  (int -> (int -> (int -> int (a:1)) function$ (a:1)) function$ (a:1))
-    function$
-type nonrec t =
-  (a:((int)[@res.namedArgLoc ]) ->
-     (b:((int)[@res.namedArgLoc ]) ->
-        (c:((int)[@res.namedArgLoc ]) -> int (a:1)) function$ (a:1))
-       function$ (a:1))
-    function$
-let (f : (x -> unit (a:1)) function$) = xf
-let (f : (x -> unit (a:1)) function$) = xf
-let (f : (int -> string -> unit (a:2)) function$) = xf
-let (t :
-  (a:((int)[@res.namedArgLoc ]) -> b:((int)[@res.namedArgLoc ]) -> int (a:2))
-    function$)
-  = xf
+  a:((int)[@res.namedArgLoc ]) ->
+    b:((int)[@res.namedArgLoc ]) ->
+      c:((int)[@res.namedArgLoc ]) -> int (a:1) (a:1) (a:1)
+let (f : x -> unit (a:1)) = xf
+let (f : x -> unit (a:1)) = xf
+let (f : int -> string -> unit (a:2)) = xf
 let (t :
-  (?a:((int)[@res.namedArgLoc ]) ->
-     ?b:((int)[@res.namedArgLoc ]) -> int (a:2))
-    function$)
+  a:((int)[@res.namedArgLoc ]) -> b:((int)[@res.namedArgLoc ]) -> int (a:2))
   = xf
 let (t :
-  (int -> (int -> (int -> int (a:1)) function$ (a:1)) function$ (a:1))
-    function$)
+  ?a:((int)[@res.namedArgLoc ]) -> ?b:((int)[@res.namedArgLoc ]) -> int (a:2))
   = xf
+let (t : int -> int -> int -> int (a:1) (a:1) (a:1)) = xf
 let (t :
-  (a:((int)[@res.namedArgLoc ]) ->
-     (b:((int)[@res.namedArgLoc ]) ->
-        (c:((int)[@res.namedArgLoc ]) -> int (a:1)) function$ (a:1))
-       function$ (a:1))
-    function$)
+  a:((int)[@res.namedArgLoc ]) ->
+    b:((int)[@res.namedArgLoc ]) ->
+      c:((int)[@res.namedArgLoc ]) -> int (a:1) (a:1) (a:1))
   = xf
 type nonrec t = f:((int)[@res.namedArgLoc ]) -> string
 type nonrec t = ?f:((int)[@res.namedArgLoc ]) -> string
 let (f : f:((int)[@res.namedArgLoc ]) -> string) = fx
 let (f : ?f:((int)[@res.namedArgLoc ]) -> string) = fx
-type nonrec t = (f:((int)[@res.namedArgLoc ]) -> string (a:1)) function$
+type nonrec t = f:((int)[@res.namedArgLoc ]) -> string (a:1)
 type nonrec t = f:((int)[@res.namedArgLoc ]) -> string
-type nonrec t =
-  (f:(((int -> string (a:1)) function$)[@res.namedArgLoc ]) -> float (a:1))
-    function$
-type nonrec t =
-  f:(((int -> string (a:1)) function$)[@res.namedArgLoc ]) -> float
-type nonrec t =
-  f:((int)[@res.namedArgLoc ]) -> (string -> float (a:1)) function$
+type nonrec t = f:((int -> string (a:1))[@res.namedArgLoc ]) -> float (a:1)
+type nonrec t = f:((int -> string (a:1))[@res.namedArgLoc ]) -> float
+type nonrec t = f:((int)[@res.namedArgLoc ]) -> string -> float (a:1)
 type nonrec t =
   ((a:((int)[@res.namedArgLoc ]) ->
       ((b:((int)[@res.namedArgLoc ]) -> ((float)[@attr ]) -> unit)[@attrBeforeLblB
                                                                     ]) (a:3))
-    [@attrBeforeLblA ]) function$
+  [@attrBeforeLblA ])
 type nonrec t =
-  (((a:((int)[@res.namedArgLoc ]) ->
-       (((b:((int)[@res.namedArgLoc ]) ->
-            (((float)[@attr ]) -> unit (a:1)) function$ (a:1))
-           function$)[@attrBeforeLblB ]) (a:1))
-      function$)[@attrBeforeLblA ])
+  ((a:((int)[@res.namedArgLoc ]) ->
+      ((b:((int)[@res.namedArgLoc ]) -> ((float)[@attr ]) -> unit (a:1) (a:1))
+      [@attrBeforeLblB ]) (a:1))[@attrBeforeLblA ])
 type nonrec t = ((a:((int)[@res.namedArgLoc ]) -> unit)[@attr ])
 type nonrec 'a getInitialPropsFn =
-  (< query: string dict  ;req: 'a Js.t Js.Nullable.t   >  ->
-     'a Js.t Js.Promise.t (a:1))
-    function$
\ No newline at end of file
+  < query: string dict  ;req: 'a Js.t Js.Nullable.t   >  ->
+    'a Js.t Js.Promise.t (a:1)
\ No newline at end of file
diff --git a/tests/syntax_tests/data/parsing/grammar/typexpr/expected/firstClassModules.res.txt b/tests/syntax_tests/data/parsing/grammar/typexpr/expected/firstClassModules.res.txt
index 105320cdf3..10dc94f361 100644
--- a/tests/syntax_tests/data/parsing/grammar/typexpr/expected/firstClassModules.res.txt
+++ b/tests/syntax_tests/data/parsing/grammar/typexpr/expected/firstClassModules.res.txt
@@ -2,7 +2,7 @@ type nonrec t = (module Hashmap)
 type nonrec t = (module Hashmap with type key = string)
 type nonrec t = (module Hashmap with type key = string and type value = int)
 type nonrec toValueLikeInstance =
-  ('a t -> (module RxValueLikeInstance.S with type a = 'a) (a:1)) function$
+  'a t -> (module RxValueLikeInstance.S with type a = 'a) (a:1)
 type nonrec 'a t = (module Test with type a = 'a)
 type nonrec t = (module Console) ref
 let (devices : (string, (module DEVICE)) Hastbl.t) = Hashtbl.creat 17
\ No newline at end of file
diff --git a/tests/syntax_tests/data/parsing/grammar/typexpr/expected/objectTypeSpreading.res.txt b/tests/syntax_tests/data/parsing/grammar/typexpr/expected/objectTypeSpreading.res.txt
index eb2c9f1c7a..bfe62dd69d 100644
--- a/tests/syntax_tests/data/parsing/grammar/typexpr/expected/objectTypeSpreading.res.txt
+++ b/tests/syntax_tests/data/parsing/grammar/typexpr/expected/objectTypeSpreading.res.txt
@@ -3,10 +3,9 @@ type nonrec u = < a ;u: int   >
 type nonrec v = < v: int  ;a  > 
 type nonrec w = < j: int  ;a ;k: int  ;v  > 
 type nonrec t = < a ;u: int   >  as 'a
-type nonrec t = (< a ;u: int   >  -> unit (a:1)) function$
-type nonrec t = ((< a ;u: int   >  as 'a) -> unit (a:1)) function$
-type nonrec t =
-  (< a ;u: int   >  -> < a ;v: int   >  -> unit (a:2)) function$
+type nonrec t = < a ;u: int   >  -> unit (a:1)
+type nonrec t = (< a ;u: int   >  as 'a) -> unit (a:1)
+type nonrec t = < a ;u: int   >  -> < a ;v: int   >  -> unit (a:2)
 type nonrec user = < name: string   > 
 let (steve : < user ;age: int   > ) =
   [%obj { name = {js|Steve|js}; age = 30 }]
diff --git a/tests/syntax_tests/data/parsing/grammar/typexpr/expected/parenthesized.res.txt b/tests/syntax_tests/data/parsing/grammar/typexpr/expected/parenthesized.res.txt
index 566d9ac548..67be279695 100644
--- a/tests/syntax_tests/data/parsing/grammar/typexpr/expected/parenthesized.res.txt
+++ b/tests/syntax_tests/data/parsing/grammar/typexpr/expected/parenthesized.res.txt
@@ -1,2 +1 @@
-type nonrec t =
-  (((a:((int)[@res.namedArgLoc ]) -> unit (a:1)) function$)[@attr ])
\ No newline at end of file
+type nonrec t = ((a:((int)[@res.namedArgLoc ]) -> unit (a:1))[@attr ])
\ No newline at end of file
diff --git a/tests/syntax_tests/data/parsing/grammar/typexpr/expected/poly.res.txt b/tests/syntax_tests/data/parsing/grammar/typexpr/expected/poly.res.txt
index 65b49722d1..cca42fdbb7 100644
--- a/tests/syntax_tests/data/parsing/grammar/typexpr/expected/poly.res.txt
+++ b/tests/syntax_tests/data/parsing/grammar/typexpr/expected/poly.res.txt
@@ -1,12 +1,8 @@
 external getLogger :
-  (unit ->
-     <
-       log: ('a -> unit (a:1)) function$  ;log2: 'a .
-                                                   (int -> int (a:1))
-                                                     function$  ;log3: 
-                                                                   'a 'b .
-                                                                    ('a ->
-                                                                    'b -> int (a:2))
-                                                                    function$
-                                                                     >  (a:1))
-    function$ = "./src/logger.mock.js"
\ No newline at end of file
+  unit ->
+    <
+      log: 'a -> unit (a:1)  ;log2: 'a . int -> int (a:1)  ;log3: 'a 'b .
+                                                                    'a ->
+                                                                    'b -> int (a:2)
+                                                                >  (a:1) =
+    "./src/logger.mock.js"
\ No newline at end of file
diff --git a/tests/syntax_tests/data/parsing/grammar/typexpr/expected/polyVariant.res.txt b/tests/syntax_tests/data/parsing/grammar/typexpr/expected/polyVariant.res.txt
index de6fd665c0..a60c0bbb66 100644
--- a/tests/syntax_tests/data/parsing/grammar/typexpr/expected/polyVariant.res.txt
+++ b/tests/syntax_tests/data/parsing/grammar/typexpr/expected/polyVariant.res.txt
@@ -3,13 +3,11 @@ module type Conjunctive  =
   sig
     type nonrec u1 = [ `A  | `B ]
     type nonrec u2 = [ `A  | `B  | `C ]
-    val f : ([< `T of [< u2]&[< u2]&[< u1] ] -> unit (a:1)) function$
-    val g : ([< `S of [< u2]&[< u2]&[< u1] ] -> unit (a:1)) function$
+    val f : [< `T of [< u2]&[< u2]&[< u1] ] -> unit (a:1)
+    val g : [< `S of [< u2]&[< u2]&[< u1] ] -> unit (a:1)
     val g :
-      ([<
-         `Exotic-S+ of [< `Exotic-u2+ ]&[< `Exotic-u2- ]&[< `Exotic-u1+++ ] ]
-         -> unit (a:1))
-        function$
+      [< `Exotic-S+ of [< `Exotic-u2+ ]&[< `Exotic-u2- ]&[< `Exotic-u1+++ ] ]
+        -> unit (a:1)
   end
 type nonrec t = [ s]
 type nonrec t = [ ListStyleType.t]
diff --git a/tests/syntax_tests/data/parsing/grammar/typexpr/expected/uncurried.res.txt b/tests/syntax_tests/data/parsing/grammar/typexpr/expected/uncurried.res.txt
index 5f9275519c..94510d9656 100644
--- a/tests/syntax_tests/data/parsing/grammar/typexpr/expected/uncurried.res.txt
+++ b/tests/syntax_tests/data/parsing/grammar/typexpr/expected/uncurried.res.txt
@@ -1,25 +1,18 @@
+type nonrec t = {
+  mutable field: float -> int -> bool -> unit (a:3) }
+type nonrec t = float -> int -> bool -> unit (a:3)
 type nonrec t =
-  {
-  mutable field: (float -> int -> bool -> unit (a:3)) function$ }
-type nonrec t = (float -> int -> bool -> unit (a:3)) function$
+  ((float)[@attr ]) ->
+    ((int)[@attr2 ]) -> ((bool)[@attr3 ]) -> ((string)[@attr4 ]) -> unit (a:4)
 type nonrec t =
-  (((float)[@attr ]) ->
-     ((int)[@attr2 ]) -> ((bool)[@attr3 ]) -> ((string)[@attr4 ]) -> unit (a:4))
-    function$
+  ((float ->
+      ((int)[@attr2 ]) ->
+        ((bool -> ((string)[@attr4 ]) -> unit (a:1) (a:1))[@attr3 ]) (a:1) (a:1))
+  [@attr ])
 type nonrec t =
-  (((float ->
-       (((int)[@attr2 ]) ->
-          (((bool -> (((string)[@attr4 ]) -> unit (a:1)) function$ (a:1))
-              function$)[@attr3 ]) (a:1))
-         function$ (a:1))
-      function$)[@attr ])
-type nonrec t =
-  (((float)[@attr ]) ->
-     ((int)[@attr2 ]) -> ((bool)[@attr3 ]) -> ((string)[@attr4 ]) -> unit (a:4))
-    function$
+  ((float)[@attr ]) ->
+    ((int)[@attr2 ]) -> ((bool)[@attr3 ]) -> ((string)[@attr4 ]) -> unit (a:4)
 external setTimeout :
-  ((unit -> unit (a:1)) function$ -> int -> timerId (a:2)) function$ =
-    "setTimeout"[@@val ]
+  (unit -> unit (a:1)) -> int -> timerId (a:2) = "setTimeout"[@@val ]
 external setTimeout :
-  ((unit -> unit (a:1)) function$ -> int -> timerId (a:2)) function$ =
-    "setTimeout"
\ No newline at end of file
+  (unit -> unit (a:1)) -> int -> timerId (a:2) = "setTimeout"
\ No newline at end of file
diff --git a/tests/syntax_tests/data/parsing/grammar/typexpr/expected/unit.res.txt b/tests/syntax_tests/data/parsing/grammar/typexpr/expected/unit.res.txt
index 9f8e5effc3..9a676f8bea 100644
--- a/tests/syntax_tests/data/parsing/grammar/typexpr/expected/unit.res.txt
+++ b/tests/syntax_tests/data/parsing/grammar/typexpr/expected/unit.res.txt
@@ -1,9 +1,9 @@
 type nonrec t = unit
-type nonrec t = (unit -> unit (a:1)) function$
-type nonrec t = (unit -> unit -> unit (a:2)) function$
-type nonrec t = (unit -> unit (a:1)) function$
-let f [arity:1](f : (unit -> unit (a:1)) function$) = f ()
-let f [arity:1](f : (unit -> unit (a:1)) function$) = f ()
-let f [arity:1](f : (unit -> unit -> unit (a:2)) function$) = f () ()
-external svg : (unit -> React.element (a:1)) function$ = "svg"
-external thing : (unit -> unit (a:1)) function$ = "svg"
\ No newline at end of file
+type nonrec t = unit -> unit (a:1)
+type nonrec t = unit -> unit -> unit (a:2)
+type nonrec t = unit -> unit (a:1)
+let f [arity:1](f : unit -> unit (a:1)) = f ()
+let f [arity:1](f : unit -> unit (a:1)) = f ()
+let f [arity:1](f : unit -> unit -> unit (a:2)) = f () ()
+external svg : unit -> React.element (a:1) = "svg"
+external thing : unit -> unit (a:1) = "svg"
\ No newline at end of file
diff --git a/tests/syntax_tests/data/parsing/infiniteLoops/expected/nonRecTypes.res.txt b/tests/syntax_tests/data/parsing/infiniteLoops/expected/nonRecTypes.res.txt
index 68389b0146..c15c53f0c6 100644
--- a/tests/syntax_tests/data/parsing/infiniteLoops/expected/nonRecTypes.res.txt
+++ b/tests/syntax_tests/data/parsing/infiniteLoops/expected/nonRecTypes.res.txt
@@ -88,29 +88,27 @@ include
         ;;int
         ;;(t value) = {js||js}
         ;;{js|BS:6.0.1\x84\x95\xa6\xbe\0\0\0#\0\0\0\r\0\0\0&\0\0\0#\x91\xa0\xa0A\xa0$size@\xa0\xa0A\xa0$root@\xa0\xa0A\xa0'compare@@|js}
-        external sizeSet : ('value t -> int -> unit (a:2)) function$ = "size"
+        external sizeSet : 'value t -> int -> unit (a:2) = "size"
         ;;{js|BS:6.0.1\x84\x95\xa6\xbe\0\0\0\x15\0\0\0\t\0\0\0\x1a\0\0\0\x19\xb0\xa0\xa0A\x91@\xa0\xa0A\x04\x03@E\x97\xa0$size@|js}
         ;;[|(({js|use sizeGet instead or use {abstract = light} explicitly|js})
             [@ocaml.deprecated ])|]
-        external size : ('value t -> int (a:1)) function$ = ""
+        external size : 'value t -> int (a:1) = ""
         ;;{js|BS:6.0.1\x84\x95\xa6\xbe\0\0\0\x10\0\0\0\x07\0\0\0\x14\0\0\0\x13\xb0\xa0\xa0A\x91@@A\x98\xa0$size@|js}
-        external sizeGet : ('value t -> int (a:1)) function$ = ""
+        external sizeGet : 'value t -> int (a:1) = ""
         ;;{js|BS:6.0.1\x84\x95\xa6\xbe\0\0\0\x10\0\0\0\x07\0\0\0\x14\0\0\0\x13\xb0\xa0\xa0A\x91@@A\x98\xa0$size@|js}
         external rootSet :
-          ('value t -> 'value node option -> unit (a:2)) function$ = "root"
+          'value t -> 'value node option -> unit (a:2) = "root"
         ;;{js|BS:6.0.1\x84\x95\xa6\xbe\0\0\0\x15\0\0\0\t\0\0\0\x1a\0\0\0\x19\xb0\xa0\xa0A\x91@\xa0\xa0A\x04\x03@E\x97\xa0$root@|js}
         ;;[|(({js|use rootGet instead or use {abstract = light} explicitly|js})
             [@ocaml.deprecated ])|]
-        external root : ('value t -> 'value node option (a:1)) function$ = ""
+        external root : 'value t -> 'value node option (a:1) = ""
         ;;{js|BS:6.0.1\x84\x95\xa6\xbe\0\0\0\x10\0\0\0\x07\0\0\0\x14\0\0\0\x13\xb0\xa0\xa0A\x91@@A\x98\xa0$root@|js}
-        external rootGet :
-          ('value t -> 'value node option (a:1)) function$ = ""
+        external rootGet : 'value t -> 'value node option (a:1) = ""
         ;;{js|BS:6.0.1\x84\x95\xa6\xbe\0\0\0\x10\0\0\0\x07\0\0\0\x14\0\0\0\x13\xb0\xa0\xa0A\x91@@A\x98\xa0$root@|js}
         ;;[|(({js|use compareGet instead or use {abstract = light} explicitly|js})
             [@ocaml.deprecated ])|]
         external compare :
-          ('value t -> [ [%rescript.typehole ]] Js.Internal.fn (a:1))
-            function$
+          'value t -> [ [%rescript.typehole ]] Js.Internal.fn (a:1)
         ;;(({js|Arity_2('value, 'value)], int) =
             ""
             "BS:6.0.1\x84\x95\xa6\xbe\0\0\0\x13\0\0\0\x07\0\0\0\x14\0\0\0\x13\xb0\xa0\xa0A\x91@@A\x98\xa0'compare@";
diff --git a/tests/syntax_tests/data/parsing/recovery/pattern/expected/constrained.res.txt b/tests/syntax_tests/data/parsing/recovery/pattern/expected/constrained.res.txt
index 3ec1fdf0e8..1f05add130 100644
--- a/tests/syntax_tests/data/parsing/recovery/pattern/expected/constrained.res.txt
+++ b/tests/syntax_tests/data/parsing/recovery/pattern/expected/constrained.res.txt
@@ -10,4 +10,4 @@
 
   Did you forget a `)` here?
 
-;;match x with | (a : (int -> unit (a:1)) function$) -> [%rescript.exprhole ]
\ No newline at end of file
+;;match x with | (a : int -> unit (a:1)) -> [%rescript.exprhole ]
\ No newline at end of file
diff --git a/tests/syntax_tests/data/ppx/react/expected/firstClassModules.res.txt b/tests/syntax_tests/data/ppx/react/expected/firstClassModules.res.txt
index 934880c83a..6d4c3beee9 100644
--- a/tests/syntax_tests/data/ppx/react/expected/firstClassModules.res.txt
+++ b/tests/syntax_tests/data/ppx/react/expected/firstClassModules.res.txt
@@ -50,7 +50,7 @@ module External = {
     props<
       module(T with type t = 'a and type key = 'key),
       option<'key>,
-      option<'key> => unit,
+      (option<'key> => unit),
       array<'a>,
     >,
     React.element,
diff --git a/tests/syntax_tests/data/ppx/react/expected/firstClassModules.resi.txt b/tests/syntax_tests/data/ppx/react/expected/firstClassModules.resi.txt
index 556f6b9f0e..54bfc7895c 100644
--- a/tests/syntax_tests/data/ppx/react/expected/firstClassModules.resi.txt
+++ b/tests/syntax_tests/data/ppx/react/expected/firstClassModules.resi.txt
@@ -17,7 +17,7 @@ module Select: {
     props<
       module(T with type t = 'a and type key = 'key),
       option<'key>,
-      option<'key> => unit,
+      (option<'key> => unit),
       array<'a>,
     >,
     React.element,
diff --git a/tests/syntax_tests/data/printer/typexpr/expected/arrow.res.txt b/tests/syntax_tests/data/printer/typexpr/expected/arrow.res.txt
index cd0180e929..0392485cb0 100644
--- a/tests/syntax_tests/data/printer/typexpr/expected/arrow.res.txt
+++ b/tests/syntax_tests/data/printer/typexpr/expected/arrow.res.txt
@@ -132,7 +132,7 @@ type t = @attr (foo, @attr2 ~f: bar, @attr3 ~f: baz) => unit
 type t = @attr (string => @attr (int => unit))
 type t = @attr (string, int) => @attr (int, float) => unit
 type t = @attr (int => @attr (int, float) => @attr (unit => unit => unit))
-type t = @attr (@attr2 ~f: int, @attr3 ~g: float) => unit
+type t = (@attr @attr2 ~f: int, @attr3 ~g: float) => unit
 
 type f = (
   @attr @attr @attr @attr @attr @attr @attr @attr @attr ~f: superLong,
diff --git a/tests/tests/src/gpr_2614_test.mjs b/tests/tests/src/gpr_2614_test.mjs
index 29ee32cd3d..27235a950b 100644
--- a/tests/tests/src/gpr_2614_test.mjs
+++ b/tests/tests/src/gpr_2614_test.mjs
@@ -17,16 +17,11 @@ function ff() {
   v.l = 2;
 }
 
-let partial_arg = "x";
-
-function h0(param) {
-  let tmp = {
+function h0(extra) {
+  return {
+    "lo-x": "x",
     hi: 2
   };
-  if (partial_arg !== undefined) {
-    tmp["lo-x"] = Primitive_option.valFromOption(partial_arg);
-  }
-  return tmp;
 }
 
 let h1 = {