diff --git a/src/proto/vim9compile.pro b/src/proto/vim9compile.pro
index 49213c8..fbee55c 100644
--- a/src/proto/vim9compile.pro
+++ b/src/proto/vim9compile.pro
@@ -1,6 +1,7 @@
 /* vim9compile.c */
 int check_defined(char_u *p, size_t len, cctx_T *cctx);
 int check_compare_types(exptype_T type, typval_T *tv1, typval_T *tv2);
+int use_typecheck(type_T *actual, type_T *expected);
 int get_script_item_idx(int sid, char_u *name, int check_writable, cctx_T *cctx);
 imported_T *find_imported(char_u *name, size_t len, cctx_T *cctx);
 imported_T *find_imported_in_script(char_u *name, size_t len, int sid);