diff --git a/src/proto/vim9class.pro b/src/proto/vim9class.pro
index a746eb7..1ed175e 100644
--- a/src/proto/vim9class.pro
+++ b/src/proto/vim9class.pro
@@ -1,5 +1,7 @@
 /* vim9class.c */
 int object_index_from_itf_index(class_T *itf, int is_method, int idx, class_T *cl);
+int is_valid_builtin_obj_methodname(char_u *funcname);
+ufunc_T *class_get_builtin_method(class_T *cl, class_builtin_T builtin_method, int *method_idx);
 void ex_class(exarg_T *eap);
 type_T *oc_member_type(class_T *cl, int is_object, char_u *name, char_u *name_end, int *member_idx);
 type_T *oc_member_type_by_idx(class_T *cl, int is_object, int member_idx);
@@ -34,6 +36,10 @@
 void defcompile_class(class_T *cl);
 void defcompile_classes_in_script(void);
 int is_class_name(char_u *name, typval_T *rettv);
+void protected_method_access_errmsg(char_u *method_name);
+int object_empty(object_T *obj);
+int object_len(object_T *obj);
+char_u *object_string(object_T *obj, char_u *numbuf, int copyID, int echo_style, int restore_copyID, int composite_val);
 int class_instance_of(class_T *cl, class_T *other_cl);
 void f_instanceof(typval_T *argvars, typval_T *rettv);
 /* vim: set ft=c : */