diff --git a/src/mlw/ocaml_printer.ml b/src/mlw/ocaml_printer.ml
index 716550b297a10f5f6a41d63fd542e05a165670af..462782d8893e26471ea7894f5ab30e3a4f58aa0b 100644
--- a/src/mlw/ocaml_printer.ml
+++ b/src/mlw/ocaml_printer.ml
@@ -588,7 +588,7 @@ module Print = struct
       match cs_args with
       | [] -> fprintf fmt "@[<hov 4>| %a@]" (print_uident info) id
       | l -> fprintf fmt "@[<hov 4>| %a of %a@]" (print_uident info) id
-               (print_list star (print_ty ~paren:false info)) l in
+               (print_list star (print_ty ~paren:true info)) l in
     let print_field fmt (is_mutable, id, ty) =
       fprintf fmt "%s%a: @[%a@];" (if is_mutable then "mutable " else "")
         (print_lident info) id (print_ty ~paren:false info) ty in