PPX v4: mark props type in externals as @live.

CHANGELOG.md

@@ -28,6 +28,7 @@
 #### :bug: Bug Fix
 
 - Fix unhandled cases for exotic idents (allow to use exotic PascalCased identifiers for types). https://github.com/rescript-lang/rescript-compiler/pull/6777
+- PPX v4: mark props type in externals as `@live` to avoid dead code warnings for prop fields in the editor tooling. https://github.com/rescript-lang/rescript-compiler/pull/6796
 
 #### :house: Internal
 

jscomp/syntax/src/jsx_v4.ml

@@ -327,15 +327,15 @@ let make_label_decls named_type_list =
            Type.field ~loc ~attrs {txt = label; loc}
              (Typ.var @@ safe_type_from_value @@ Labelled label))
 
-let make_type_decls props_name loc named_type_list =
+let make_type_decls ~attrs props_name loc named_type_list =
   let label_decl_list = make_label_decls named_type_list in
   (* 'id, 'className, ... *)
   let params =
     make_props_type_params_tvar named_type_list
     |> List.map (fun core_type -> (core_type, Invariant))
   in
   [
-    Type.mk ~loc ~params {txt = props_name; loc}
+    Type.mk ~attrs ~loc ~params {txt = props_name; loc}
       ~kind:(Ptype_record label_decl_list);
   ]
 
@@ -346,22 +346,26 @@ let make_type_decls_with_core_type props_name loc core_type typ_vars =
       ~manifest:core_type;
   ]
 
+let live_attr = ({txt = "live"; loc = Location.none}, PStr [])
+
 (* type props<'x, 'y, ...> = { x: 'x, y?: 'y, ... } *)
-let make_props_record_type ~core_type_of_attr ~typ_vars_of_core_type props_name
-    loc named_type_list =
+let make_props_record_type ~core_type_of_attr ~external_ ~typ_vars_of_core_type
+    props_name loc named_type_list =
+  let attrs = if external_ then [live_attr] else [] in
   Str.type_ Nonrecursive
     (match core_type_of_attr with
-    | None -> make_type_decls props_name loc named_type_list
+    | None -> make_type_decls ~attrs props_name loc named_type_list
     | Some core_type ->
       make_type_decls_with_core_type props_name loc core_type
         typ_vars_of_core_type)
 
 (* type props<'x, 'y, ...> = { x: 'x, y?: 'y, ... } *)
-let make_props_record_type_sig ~core_type_of_attr ~typ_vars_of_core_type
-    props_name loc named_type_list =
+let make_props_record_type_sig ~core_type_of_attr ~external_
+    ~typ_vars_of_core_type props_name loc named_type_list =
+  let attrs = if external_ then [live_attr] else [] in
   Sig.type_ Nonrecursive
     (match core_type_of_attr with
-    | None -> make_type_decls props_name loc named_type_list
+    | None -> make_type_decls ~attrs props_name loc named_type_list
     | Some core_type ->
       make_type_decls_with_core_type props_name loc core_type
         typ_vars_of_core_type)
@@ -950,8 +954,8 @@ let map_binding ~config ~empty_loc ~pstr_loc ~file_name ~rec_flag binding =
     let named_type_list = List.fold_left arg_to_type [] named_arg_list in
     (* type props = { ... } *)
     let props_record_type =
-      make_props_record_type ~core_type_of_attr ~typ_vars_of_core_type "props"
-        pstr_loc named_type_list
+      make_props_record_type ~core_type_of_attr ~external_:false
+        ~typ_vars_of_core_type "props" pstr_loc named_type_list
     in
     let inner_expression =
       Exp.apply
@@ -1211,8 +1215,8 @@ let transform_structure_item ~config item =
       in
       (* type props<'x, 'y> = { x: 'x, y?: 'y, ... } *)
       let props_record_type =
-        make_props_record_type ~core_type_of_attr ~typ_vars_of_core_type "props"
-          pstr_loc named_type_list
+        make_props_record_type ~core_type_of_attr ~external_:true
+          ~typ_vars_of_core_type "props" pstr_loc named_type_list
       in
       (* can't be an arrow because it will defensively uncurry *)
       let new_external_type =
@@ -1317,9 +1321,10 @@ let transform_signature_item ~config item =
             | [] -> []
             | _ -> [Typ.any ()]))
       in
+      let external_ = psig_desc.pval_prim <> [] in
       let props_record_type =
-        make_props_record_type_sig ~core_type_of_attr ~typ_vars_of_core_type
-          "props" psig_loc named_type_list
+        make_props_record_type_sig ~core_type_of_attr ~external_
+          ~typ_vars_of_core_type "props" psig_loc named_type_list
       in
       (* can't be an arrow because it will defensively uncurry *)
       let new_external_type =

jscomp/syntax/tests/ppx/react/expected/externalWithCustomName.res.txt

@@ -13,6 +13,7 @@ let t = React.createElement(Foo.component, Foo.componentProps(~a=1, ~b={"1"}, ()
 @@jsxConfig({version: 4, mode: "classic"})
 
 module Foo = {
+  @live
   type props<'a, 'b> = {a: 'a, b: 'b}
 
   @module("Foo")
@@ -24,6 +25,7 @@ let t = React.createElement(Foo.component, {a: 1, b: "1"})
 @@jsxConfig({version: 4, mode: "automatic"})
 
 module Foo = {
+  @live
   type props<'a, 'b> = {a: 'a, b: 'b}
 
   @module("Foo")

jscomp/syntax/tests/ppx/react/expected/externalWithRef.res.txt

@@ -18,6 +18,7 @@ module V3 = {
 @@jsxConfig({version: 4, mode: "classic"})
 
 module V4C = {
+  @live
   type props<'x, 'ref> = {
     x: 'x,
     ref?: 'ref,
@@ -28,9 +29,21 @@ module V4C = {
     "component"
 }
 
+module type V4CType = {
+  @live
+  type props<'x, 'y> = {
+    x: 'x,
+    y: 'y,
+  }
+
+  @module("someModule")
+  external make: React.componentLike<props<string, string>, React.element> = "component"
+}
+
 @@jsxConfig({version: 4, mode: "automatic"})
 
 module V4C = {
+  @live
   type props<'x, 'ref> = {
     x: 'x,
     ref?: 'ref,

jscomp/syntax/tests/ppx/react/expected/externalWithTypeVariables.res.txt

@@ -16,6 +16,7 @@ module V3 = {
 @@jsxConfig({version: 4, mode: "classic"})
 
 module V4C = {
+  @live
   type props<'x, 'children> = {
     x: 'x,
     children: 'children,
@@ -28,6 +29,7 @@ module V4C = {
 @@jsxConfig({version: 4, mode: "automatic"})
 
 module V4C = {
+  @live
   type props<'x, 'children> = {
     x: 'x,
     children: 'children,

jscomp/syntax/tests/ppx/react/expected/firstClassModules.res.txt

@@ -88,6 +88,7 @@ module External = {
     type key
     type t
   }
+  @live
   type props<'model, 'selected, 'onChange, 'items> = {
     model: 'model,
     selected: 'selected,

jscomp/syntax/tests/ppx/react/expected/mangleKeyword.res.txt

@@ -47,6 +47,7 @@ module C4C0 = {
   }
 }
 module C4C1 = {
+  @live
   type props<'T_open, 'T_type> = {@as("open") _open: 'T_open, @as("type") _type: 'T_type}
 
   external make: @as("open") React.componentLike<props<string, string>, React.element> = "default"
@@ -68,6 +69,7 @@ module C4A0 = {
   }
 }
 module C4A1 = {
+  @live
   type props<'T_open, 'T_type> = {@as("open") _open: 'T_open, @as("type") _type: 'T_type}
 
   external make: @as("open") React.componentLike<props<string, string>, React.element> = "default"

jscomp/syntax/tests/ppx/react/expected/noPropsWithKey.res.txt

@@ -12,6 +12,7 @@ module V4CA = {
 }
 
 module V4CB = {
+  @live
   type props = {}
 
   @module("c")
@@ -51,6 +52,7 @@ module V4CA = {
 }
 
 module V4CB = {
+  @live
   type props = {}
 
   @module("c")

jscomp/syntax/tests/ppx/react/expected/v4.res.txt

@@ -35,12 +35,14 @@ module type TUncurried = {
 }
 
 module E = {
+  @live
   type props<'x> = {x: 'x}
 
   external make: React.componentLike<props<string>, React.element> = "default"
 }
 
 module EUncurried = {
+  @live
   type props<'x> = {x: 'x}
 
   external make: React.componentLike<props<string>, React.element> = "default"

jscomp/syntax/tests/ppx/react/externalWithRef.res

@@ -18,6 +18,14 @@ module V4C = {
     ) => React.element = "component"
 }
 
+module type V4CType = {
+  @module("someModule") @react.component
+    external make: (
+      ~x: string,
+      ~y: string,
+    ) => React.element = "component"
+}
+
 @@jsxConfig({version: 4, mode: "automatic"})
 
 module V4C = {