Keep field renames in object spreads

Signed-off-by: Cristiano Calcagno <cristianoc@users.noreply.github.com>

Author: cristianoc

CHANGELOG.md

@@ -37,6 +37,7 @@
 #### :bug: Bug fix
 
 - Fix the side-effect analysis treating bigint exponentiation and bounds-checked array and string reads as pure, which let dead-code elimination drop an unused one that throws: `let _ = 2n ** -1n` no longer raised. https://github.com/rescript-lang/rescript/pull/8617
+- Preserve record field `@as` annotations when formatting object types containing spreads. https://github.com/rescript-lang/rescript/pull/8619
 - Fix excessive parentheses and indentation in function assignments to refs, align record and array assignment formatting across refs and fields, and preserve function return-type parentheses and consistent JSX fragment layout in callbacks. https://github.com/rescript-lang/rescript/pull/8611
 - Report an error instead of crashing when an integer in a variant constructor's `@as` annotation exceeds the compiler's integer range. https://github.com/rescript-lang/rescript/pull/8619
 - Warn about an `@as` on a record field whose payload does not name the field, such as `@as(42)`. It renamed nothing and was silently accepted. https://github.com/rescript-lang/rescript/pull/8619

compiler/syntax/src/res_core.ml

@@ -5892,13 +5892,13 @@ and parse_spread_tail_classified ?current_type_name_path ?inline_types_context
       (* Object-style: build an object type that inherits the spread *)
       let obj_fields =
         let convert (ld : Parsetree.label_declaration) =
-          let ({Parsetree.pld_name; pld_type; pld_attributes; _}
-                : Parsetree.label_declaration) =
+          let ({Parsetree.pld_name; pld_type; _} : Parsetree.label_declaration)
+              =
             ld
           in
           match pld_name.txt with
           | "..." -> Parsetree.Oinherit pld_type
-          | _ -> Otag (pld_name, pld_attributes, pld_type)
+          | _ -> Otag (pld_name, Ast_helper.Type.field_attributes ld, pld_type)
         in
         Parsetree.Oinherit spread_typ :: List.map convert fields
       in
@@ -5979,7 +5979,9 @@ and parse_record_or_object_decl ?current_type_name_path ?inline_types_context p
           Ext_list.map fields (fun ld ->
               match ld.pld_name.txt with
               | "..." -> Parsetree.Oinherit ld.pld_type
-              | _ -> Otag (ld.pld_name, ld.pld_attributes, ld.pld_type))
+              | _ ->
+                Otag
+                  (ld.pld_name, Ast_helper.Type.field_attributes ld, ld.pld_type))
         in
         let dot_field = Parsetree.Oinherit typ in
         let typ_obj = Ast_helper.Typ.object_ (dot_field :: fields) Closed in

tests/syntax_tests/data/printer/ObjectSpreadFieldAs.res

@@ -0,0 +1,3 @@
+type base = {"a": int}
+
+type extended = {...base, @as("renamed") "b": int}

tests/syntax_tests/data/printer/expected/ObjectSpreadFieldAs.res.txt

@@ -0,0 +1,3 @@
+type base = {"a": int}
+
+type extended = {...base, @as("renamed") "b": int}