diff --git a/src/proto/typval.pro b/src/proto/typval.pro
index f6dd01e..b1864bc 100644
--- a/src/proto/typval.pro
+++ b/src/proto/typval.pro
@@ -11,6 +11,7 @@
 float_T tv_get_float(typval_T *varp);
 int check_for_string_arg(typval_T *args, int idx);
 int check_for_nonempty_string_arg(typval_T *args, int idx);
+int check_for_number_arg(typval_T *args, int idx);
 int check_for_dict_arg(typval_T *args, int idx);
 char_u *tv_get_string(typval_T *varp);
 char_u *tv_get_string_strict(typval_T *varp);