AST: store the attributes directly on function arguments.

cristianoc · cristianoc · commit 5429398fef06 · 2025-07-18T08:46:02.000+02:00
Functions of several arguments are stored as nested `Ptyp_arrow` ast nodes, with attributes at toplevel in the node.
This change adds an attribute field to type arguments, makin it impossible to distinguish attributes on arguments from attributes on the entire function.
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -19,6 +19,7 @@
 #### :nail_care: Polish
 
 - Add missing backtick and spaces to `Belt.Map.map` doc comment. https://github.com/rescript-lang/rescript/pull/7632
+- AST: store the attributes directly on function arguments. https://github.com/rescript-lang/rescript/pull/7660
 
 #### :house: Internal
 
diff --git a/compiler/frontend/ast_core_type.ml b/compiler/frontend/ast_core_type.ml
@@ -95,7 +95,7 @@ let from_labels ~loc arity labels : t =
   in
   let args =
     Ext_list.map2 labels tyvars (fun label tyvar ->
-        {Parsetree.lbl = Asttypes.Labelled label; typ = tyvar})
+        {Parsetree.attrs = []; lbl = Asttypes.Labelled label; typ = tyvar})
   in
   Typ.arrows ~loc args result_type
 
@@ -143,7 +143,8 @@ let mk_fn_type (new_arg_types_ty : param_type list) (result : t) : t =
     Ext_list.fold_right new_arg_types_ty result
       (fun {label; ty; attr; loc} acc ->
         Ast_helper.Typ.arrow ~loc ~attrs:attr ~arity:None
-          {lbl = label; typ = ty} acc)
+          {attrs = []; lbl = label; typ = ty}
+          acc)
   in
   match t.ptyp_desc with
   | Ptyp_arrow arr ->
@@ -156,12 +157,7 @@ let list_of_arrow (ty : t) : t * param_type list =
     match ty.ptyp_desc with
     | Ptyp_arrow {arg; ret; arity} when arity = None || acc = [] ->
       aux ret
-        (({
-            label = arg.lbl;
-            ty = arg.typ;
-            attr = ty.ptyp_attributes;
-            loc = ty.ptyp_loc;
-          }
+        (({label = arg.lbl; ty = arg.typ; attr = arg.attrs; loc = ty.ptyp_loc}
            : param_type)
         :: acc)
     | Ptyp_poly (_, ty) ->
diff --git a/compiler/frontend/ast_derive_abstract.ml b/compiler/frontend/ast_derive_abstract.ml
@@ -84,7 +84,7 @@ let handle_tdcl light (tdcl : Parsetree.type_declaration) :
         ( [],
           (if has_optional_field then
              Ast_helper.Typ.arrow ~loc ~arity:None
-               {lbl = Nolabel; typ = Ast_literal.type_unit ()}
+               {attrs = []; lbl = Nolabel; typ = Ast_literal.type_unit ()}
                core_type
            else core_type),
           [] )
@@ -116,19 +116,19 @@ let handle_tdcl light (tdcl : Parsetree.type_declaration) :
             if is_optional then
               let optional_type = Ast_core_type.lift_option_type pld_type in
               ( Ast_helper.Typ.arrow ~loc:pld_loc ~arity
-                  {lbl = Asttypes.Optional pld_name; typ = pld_type}
+                  {attrs = []; lbl = Asttypes.Optional pld_name; typ = pld_type}
                   maker,
                 Val.mk ~loc:pld_loc
                   (if light then pld_name
                    else {pld_name with txt = pld_name.txt ^ "Get"})
                   ~attrs:get_optional_attrs ~prim
                   (Ast_helper.Typ.arrow ~loc ~arity:(Some 1)
-                     {lbl = Nolabel; typ = core_type}
+                     {attrs = []; lbl = Nolabel; typ = core_type}
                      optional_type)
                 :: acc )
             else
               ( Ast_helper.Typ.arrow ~loc:pld_loc ~arity
-                  {lbl = Asttypes.Labelled pld_name; typ = pld_type}
+                  {attrs = []; lbl = Asttypes.Labelled pld_name; typ = pld_type}
                   maker,
                 Val.mk ~loc:pld_loc
                   (if light then pld_name
@@ -140,7 +140,7 @@ let handle_tdcl light (tdcl : Parsetree.type_declaration) :
                        [External_arg_spec.dummy] Return_identity
                        (Js_get {js_get_name = prim_as_name; js_get_scopes = []}))
                   (Ast_helper.Typ.arrow ~loc ~arity:(Some 1)
-                     {lbl = Nolabel; typ = core_type}
+                     {attrs = []; lbl = Nolabel; typ = core_type}
                      pld_type)
                 :: acc )
           in
@@ -149,9 +149,9 @@ let handle_tdcl light (tdcl : Parsetree.type_declaration) :
             if is_current_field_mutable then
               let setter_type =
                 Ast_helper.Typ.arrow ~arity:(Some 2)
-                  {lbl = Nolabel; typ = core_type}
+                  {attrs = []; lbl = Nolabel; typ = core_type}
                   (Ast_helper.Typ.arrow ~arity:None
-                     {lbl = Nolabel; typ = pld_type} (* setter *)
+                     {attrs = []; lbl = Nolabel; typ = pld_type} (* setter *)
                      (Ast_literal.type_unit ()))
               in
               Val.mk ~loc:pld_loc
diff --git a/compiler/frontend/ast_derive_js_mapper.ml b/compiler/frontend/ast_derive_js_mapper.ml
@@ -69,7 +69,9 @@ let erase_type_str =
   Str.primitive
     (Val.mk ~prim:["%identity"]
        {loc = noloc; txt = erase_type_lit}
-       (Ast_helper.Typ.arrow ~arity:(Some 1) {lbl = Nolabel; typ = any} any))
+       (Ast_helper.Typ.arrow ~arity:(Some 1)
+          {attrs = []; lbl = Nolabel; typ = any}
+          any))
 
 let unsafe_index = "_index"
 
@@ -79,8 +81,11 @@ let unsafe_index_get =
     (Val.mk ~prim:[""]
        {loc = noloc; txt = unsafe_index}
        ~attrs:[Ast_attributes.get_index]
-       (Ast_helper.Typ.arrow ~arity:None {lbl = Nolabel; typ = any}
-          (Ast_helper.Typ.arrow ~arity:None {lbl = Nolabel; typ = any} any)))
+       (Ast_helper.Typ.arrow ~arity:None
+          {attrs = []; lbl = Nolabel; typ = any}
+          (Ast_helper.Typ.arrow ~arity:None
+             {attrs = []; lbl = Nolabel; typ = any}
+             any)))
 
 let unsafe_index_get_exp = Exp.ident {loc = noloc; txt = Lident unsafe_index}
 
@@ -132,7 +137,7 @@ let app1 = Ast_compatible.app1
 let app2 = Ast_compatible.app2
 
 let ( ->~ ) a b =
-  Ast_helper.Typ.arrow ~arity:(Some 1) {lbl = Nolabel; typ = a} b
+  Ast_helper.Typ.arrow ~arity:(Some 1) {attrs = []; lbl = Nolabel; typ = a} b
 
 let raise_when_not_found_ident =
   Longident.Ldot (Lident Primitive_modules.util, "raiseWhenNotFound")
@@ -305,7 +310,7 @@ let init () =
               let to_js_type result =
                 Ast_comb.single_non_rec_val pat_to_js
                   (Ast_helper.Typ.arrow ~arity:(Some 1)
-                     {lbl = Nolabel; typ = core_type}
+                     {attrs = []; lbl = Nolabel; typ = 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
@@ -137,7 +137,7 @@ let init () =
                 Ext_list.map label_declarations (fun {pld_name; pld_type} ->
                     Ast_comb.single_non_rec_val ?attrs:gentype_attrs pld_name
                       (Ast_helper.Typ.arrow ~arity:(Some 1)
-                         {lbl = Nolabel; typ = core_type}
+                         {attrs = []; lbl = Nolabel; typ = core_type}
                          pld_type
                          (*arity will alwys be 1 since these are single param functions*)))
               | Ptype_variant constructor_declarations ->
@@ -170,7 +170,8 @@ let init () =
                       {loc; txt = Ext_string.uncapitalize_ascii con_name}
                       (Ext_list.fold_right pcd_args annotate_type (fun x acc ->
                            Ast_helper.Typ.arrow ~arity:None
-                             {lbl = Nolabel; typ = x} acc)
+                             {attrs = []; lbl = Nolabel; typ = x}
+                             acc)
                       |> add_arity ~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
@@ -43,7 +43,7 @@ let handle_external loc (x : string) : Parsetree.expression =
         Ast_external_mk.local_external_apply loc ~pval_prim:["#raw_expr"]
           ~pval_type:
             (Ast_helper.Typ.arrow ~arity:(Some 1)
-               {lbl = Nolabel; typ = Ast_helper.Typ.any ()}
+               {attrs = []; lbl = Nolabel; typ = Ast_helper.Typ.any ()}
                (Ast_helper.Typ.any ()))
           [str_exp];
     }
@@ -72,7 +72,7 @@ let handle_debugger loc (payload : Ast_payload.t) =
     Ast_external_mk.local_external_apply loc ~pval_prim:["%debugger"]
       ~pval_type:
         (Ast_helper.Typ.arrow ~arity:(Some 1)
-           {lbl = Nolabel; typ = Ast_helper.Typ.any ()}
+           {attrs = []; lbl = Nolabel; typ = Ast_helper.Typ.any ()}
            (Ast_literal.type_unit ()))
       [Ast_literal.val_unit ~loc ()]
   | _ ->
@@ -99,7 +99,7 @@ let handle_raw ~kind loc payload =
         Ast_external_mk.local_external_apply loc ~pval_prim:["#raw_expr"]
           ~pval_type:
             (Ast_helper.Typ.arrow ~arity:(Some 1)
-               {lbl = Nolabel; typ = Ast_helper.Typ.any ()}
+               {attrs = []; lbl = Nolabel; typ = Ast_helper.Typ.any ()}
                (Ast_helper.Typ.any ()))
           [exp];
       pexp_attributes =
@@ -128,11 +128,16 @@ let handle_ffi ~loc ~payload =
       let unit = Ast_literal.type_unit ~loc () in
       let rec arrow ~arity =
         if arity = 0 then
-          Ast_helper.Typ.arrow ~arity:None ~loc {lbl = Nolabel; typ = unit} any
+          Ast_helper.Typ.arrow ~arity:None ~loc
+            {attrs = []; lbl = Nolabel; typ = unit}
+            any
         else if arity = 1 then
-          Ast_helper.Typ.arrow ~arity:None ~loc {lbl = Nolabel; typ = any} any
+          Ast_helper.Typ.arrow ~arity:None ~loc
+            {attrs = []; lbl = Nolabel; typ = any}
+            any
         else
-          Ast_helper.Typ.arrow ~loc ~arity:None {lbl = Nolabel; typ = any}
+          Ast_helper.Typ.arrow ~loc ~arity:None
+            {attrs = []; lbl = Nolabel; typ = any}
             (arrow ~arity:(arity - 1))
       in
       match !is_function with
@@ -152,7 +157,7 @@ let handle_ffi ~loc ~payload =
           Ast_external_mk.local_external_apply loc ~pval_prim:["#raw_expr"]
             ~pval_type:
               (Ast_helper.Typ.arrow ~arity:(Some 1)
-                 {lbl = Nolabel; typ = Ast_helper.Typ.any ()}
+                 {attrs = []; lbl = Nolabel; typ = Ast_helper.Typ.any ()}
                  (Ast_helper.Typ.any ()))
             [exp];
         pexp_attributes =
@@ -171,7 +176,7 @@ let handle_raw_structure loc payload =
           Ast_external_mk.local_external_apply loc ~pval_prim:["#raw_stmt"]
             ~pval_type:
               (Ast_helper.Typ.arrow ~arity:(Some 1)
-                 {lbl = Nolabel; typ = Ast_helper.Typ.any ()}
+                 {attrs = []; lbl = Nolabel; typ = Ast_helper.Typ.any ()}
                  (Ast_helper.Typ.any ()))
             [exp];
       }
diff --git a/compiler/frontend/ast_typ_uncurry.ml b/compiler/frontend/ast_typ_uncurry.ml
@@ -32,7 +32,9 @@ let to_method_callback_type loc (mapper : Bs_ast_mapper.mapper)
   let first_arg = mapper.typ mapper first_arg in
   let typ = mapper.typ mapper typ in
   let meth_type =
-    Ast_helper.Typ.arrow ~loc ~arity:None {lbl = label; typ = first_arg} typ
+    Ast_helper.Typ.arrow ~loc ~arity:None
+      {attrs = []; lbl = label; typ = first_arg}
+      typ
   in
   let arity = Ast_core_type.get_uncurry_arity meth_type in
   match arity with
@@ -58,7 +60,9 @@ let to_uncurry_type loc (mapper : Bs_ast_mapper.mapper)
   let typ = mapper.typ mapper typ in
 
   let fn_type =
-    Ast_helper.Typ.arrow ~loc ~arity:None {lbl = label; typ = first_arg} typ
+    Ast_helper.Typ.arrow ~loc ~arity:None
+      {attrs = []; lbl = label; typ = first_arg}
+      typ
   in
   let arity = Ast_core_type.get_uncurry_arity fn_type in
   let fn_type =
diff --git a/compiler/ml/ast_mapper_from0.ml b/compiler/ml/ast_mapper_from0.ml
@@ -99,8 +99,8 @@ module T = struct
     | Ptyp_var s -> Typ.var ~loc ~attrs s
     | Ptyp_arrow (lbl, t1, t2) ->
       let lbl = Asttypes.to_arg_label lbl in
-      Typ.arrow ~loc ~attrs ~arity:None
-        {lbl; typ = sub.typ sub t1}
+      Typ.arrow ~loc ~arity:None
+        {attrs; lbl; typ = sub.typ sub t1}
         (sub.typ sub t2)
     | Ptyp_tuple tyl -> Typ.tuple ~loc ~attrs (List.map (sub.typ sub) tyl)
     | Ptyp_constr (lid, tl) -> (
diff --git a/compiler/ml/parsetree.ml b/compiler/ml/parsetree.ml
@@ -73,7 +73,7 @@ and core_type = {
   ptyp_attributes: attributes; (* ... [@id1] [@id2] *)
 }
 
-and arg = {lbl: arg_label; typ: core_type}
+and arg = {attrs: attributes; lbl: arg_label; typ: core_type}
 
 and core_type_desc =
   | Ptyp_any (*  _ *)
diff --git a/compiler/ml/pprintast.ml b/compiler/ml/pprintast.ml
@@ -285,11 +285,15 @@ let tyvar f str = pp f "'%s" str
 let tyvar_loc f str = pp f "'%s" str.txt
 let string_quot f x = pp f "`%s" x
 
-let rec type_with_label ctxt f (label, c) =
-  match label with
-  | Nolabel -> core_type1 ctxt f c (* otherwise parenthesize *)
-  | Labelled {txt = s} -> pp f "%s:%a" s (core_type1 ctxt) c
-  | Optional {txt = s} -> pp f "?%s:%a" s (core_type1 ctxt) c
+let rec type_with_label ctxt f arg =
+  match arg.lbl with
+  | Nolabel ->
+    pp f "%a%a" (core_type1 ctxt) arg.typ (attributes ctxt) arg.attrs
+    (* otherwise parenthesize *)
+  | Labelled {txt = s} ->
+    pp f "%s:%a%a" s (core_type1 ctxt) arg.typ (attributes ctxt) arg.attrs
+  | Optional {txt = s} ->
+    pp f "?%s:%a%a" s (core_type1 ctxt) arg.typ (attributes ctxt) arg.attrs
 
 and core_type ctxt f x =
   if x.ptyp_attributes <> [] then
@@ -300,7 +304,7 @@ and core_type ctxt f x =
     match x.ptyp_desc with
     | Ptyp_arrow {arg; ret; arity} ->
       pp f "@[<2>%a@;->@;%a%s@]" (* FIXME remove parens later *)
-        (type_with_label ctxt) (arg.lbl, arg.typ) (core_type ctxt) ret
+        (type_with_label ctxt) arg (core_type ctxt) ret
         (match arity with
         | None -> ""
         | Some n -> " (a:" ^ string_of_int n ^ ")")
diff --git a/compiler/syntax/src/jsx_v4.ml b/compiler/syntax/src/jsx_v4.ml
@@ -918,20 +918,16 @@ let transform_structure_item ~config item =
         |> Option.map Jsx_common.typ_vars_of_core_type
         |> Option.value ~default:[]
       in
-      let rec get_prop_types types
-          ({ptyp_loc; ptyp_desc; ptyp_attributes} as full_type) =
+      let rec get_prop_types types ({ptyp_loc; ptyp_desc} as full_type) =
         match ptyp_desc with
         | Ptyp_arrow {arg; ret = {ptyp_desc = Ptyp_arrow _} as typ2}
           when is_labelled arg.lbl || is_optional arg.lbl ->
-          get_prop_types
-            ((arg.lbl, ptyp_attributes, ptyp_loc, arg.typ) :: types)
-            typ2
+          get_prop_types ((arg.lbl, arg.attrs, ptyp_loc, arg.typ) :: types) typ2
         | Ptyp_arrow {arg = {lbl = Nolabel}; ret} -> get_prop_types types ret
         | Ptyp_arrow {arg; ret = return_value}
           when is_labelled arg.lbl || is_optional arg.lbl ->
           ( return_value,
-            (arg.lbl, ptyp_attributes, return_value.ptyp_loc, arg.typ) :: types
-          )
+            (arg.lbl, arg.attrs, return_value.ptyp_loc, arg.typ) :: types )
         | _ -> (full_type, types)
       in
       let inner_type, prop_types = get_prop_types [] pval_type in
@@ -1027,9 +1023,7 @@ let transform_signature_item ~config item =
         match ptyp_desc with
         | Ptyp_arrow {arg; ret = {ptyp_desc = Ptyp_arrow _} as rest}
           when is_optional arg.lbl || is_labelled arg.lbl ->
-          get_prop_types
-            ((arg.lbl, arg.typ.ptyp_attributes, ptyp_loc, arg.typ) :: types)
-            rest
+          get_prop_types ((arg.lbl, arg.attrs, ptyp_loc, arg.typ) :: types) rest
         | Ptyp_arrow
             {
               arg =
@@ -1045,8 +1039,7 @@ let transform_signature_item ~config item =
         | Ptyp_arrow {arg; ret = return_value}
           when is_optional arg.lbl || is_labelled arg.lbl ->
           ( return_value,
-            (arg.lbl, arg.typ.ptyp_attributes, return_value.ptyp_loc, arg.typ)
-            :: types )
+            (arg.lbl, arg.attrs, return_value.ptyp_loc, arg.typ) :: types )
         | _ -> (full_type, types)
       in
       let inner_type, prop_types = get_prop_types [] pval_type in
diff --git a/compiler/syntax/src/res_core.ml b/compiler/syntax/src/res_core.ml
@@ -4039,7 +4039,8 @@ and parse_poly_type_expr ?current_type_name_path ?inline_types_context p =
         let typ = Ast_helper.Typ.var ~loc:var.loc var.txt in
         let return_type = parse_typ_expr ~alias:false p in
         let loc = mk_loc typ.Parsetree.ptyp_loc.loc_start p.prev_end_pos in
-        Ast_helper.Typ.arrow ~loc ~arity:(Some 1) {lbl = Nolabel; typ}
+        Ast_helper.Typ.arrow ~loc ~arity:(Some 1)
+          {attrs = []; lbl = Nolabel; typ}
           return_type
       | _ -> Ast_helper.Typ.var ~loc:var.loc var.txt)
     | _ -> assert false)
@@ -4400,7 +4401,7 @@ and parse_es6_arrow_type ~attrs p =
     Parser.expect EqualGreater p;
     let return_type = parse_typ_expr ~alias:false p in
     let loc = mk_loc start_pos p.prev_end_pos in
-    Ast_helper.Typ.arrow ~loc ~attrs ~arity:None {lbl; typ} return_type
+    Ast_helper.Typ.arrow ~loc ~arity:None {attrs; lbl; typ} return_type
   | DocComment _ -> assert false
   | _ ->
     let parameters = parse_type_parameters p in
@@ -4429,7 +4430,7 @@ and parse_es6_arrow_type ~attrs p =
             | _ -> arity
           in
           let t_arg =
-            Ast_helper.Typ.arrow ~loc ~attrs ~arity:None {lbl = arg_lbl; typ} t
+            Ast_helper.Typ.arrow ~loc ~arity:None {attrs; lbl = arg_lbl; typ} t
           in
           if param_num = 1 then
             (param_num - 1, Ast_uncurried.uncurried_type ~arity t_arg, 1)
@@ -4493,7 +4494,9 @@ and parse_arrow_type_rest ~es6_arrow ~start_pos typ p =
     Parser.next p;
     let return_type = parse_typ_expr ~alias:false p in
     let loc = mk_loc start_pos p.prev_end_pos in
-    Ast_helper.Typ.arrow ~loc ~arity:(Some 1) {lbl = Nolabel; typ} return_type
+    Ast_helper.Typ.arrow ~loc ~arity:(Some 1)
+      {attrs = []; lbl = Nolabel; typ}
+      return_type
   | _ -> typ
 
 and parse_typ_expr_region p =
@@ -5151,7 +5154,8 @@ and parse_type_equation_or_constr_decl p =
         let return_type = parse_typ_expr ~alias:false p in
         let loc = mk_loc uident_start_pos p.prev_end_pos in
         let arrow_type =
-          Ast_helper.Typ.arrow ~loc ~arity:(Some 1) {lbl = Nolabel; typ}
+          Ast_helper.Typ.arrow ~loc ~arity:(Some 1)
+            {attrs = []; lbl = Nolabel; typ}
             return_type
         in
         let typ = parse_type_alias p arrow_type in
diff --git a/compiler/syntax/src/res_parsetree_viewer.ml b/compiler/syntax/src/res_parsetree_viewer.ml
diff --git a/compiler/syntax/src/res_parsetree_viewer.mli b/compiler/syntax/src/res_parsetree_viewer.mli
diff --git a/compiler/syntax/src/res_printer.ml b/compiler/syntax/src/res_printer.ml
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
diff --git a/tests/syntax_tests/data/ppx/react/expected/mangleKeyword.res.txt b/tests/syntax_tests/data/ppx/react/expected/mangleKeyword.res.txt
diff --git a/tests/syntax_tests/data/printer/typexpr/expected/arrow.res.txt b/tests/syntax_tests/data/printer/typexpr/expected/arrow.res.txt

Original file line number	Diff line number	Diff line change
`@@ -73,7 +73,7 @@ and core_type = {`
`73`	`73`	`ptyp_attributes: attributes; (* ... [@id1] [@id2] *)`
`74`	`74`	`}`
`75`	`75`
`76`		`-and arg = {lbl: arg_label; typ: core_type}`
	`76`	`+and arg = {attrs: attributes; lbl: arg_label; typ: core_type}`
`77`	`77`
`78`	`78`	`and core_type_desc =`
`79`	`79`	`\| Ptyp_any (* _ *)`