diff --git a/src/mlw/ocaml_printer.ml b/src/mlw/ocaml_printer.ml
index c6d1559b66fa55f45fa67db0337ce0a1dbd31d42..468b4e3bb46b4215a2d028a2374b4bab60ab4391 100644
--- a/src/mlw/ocaml_printer.ml
+++ b/src/mlw/ocaml_printer.ml
@@ -589,7 +589,7 @@ 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