diff --git a/src/proto/vim9compile.pro b/src/proto/vim9compile.pro
index 2b62b6c..5910c67 100644
--- a/src/proto/vim9compile.pro
+++ b/src/proto/vim9compile.pro
@@ -17,6 +17,7 @@
 int assignment_len(char_u *p, int *heredoc);
 void vim9_declare_error(char_u *name);
 int check_vim9_unlet(char_u *name);
+int check_global_and_subst(char_u *cmd, char_u *arg);
 int compile_def_function(ufunc_T *ufunc, int check_return_type, compiletype_T compile_type, cctx_T *outer_cctx);
 void set_function_type(ufunc_T *ufunc);
 void delete_instr(isn_T *isn);