diff --git a/src/userfunc.c b/src/userfunc.c
index 8579c3b..b49cef1 100644
--- a/src/userfunc.c
+++ b/src/userfunc.c
@@ -82,7 +82,8 @@
     }
 
     // Vim9 script: cannot use script var name for argument.
-    if (argtypes != NULL && script_var_exists(arg, p - arg, FALSE, NULL) == OK)
+    if (!skip && argtypes != NULL && script_var_exists(arg, p - arg,
+							    FALSE, NULL) == OK)
     {
 	semsg(_(e_variable_already_declared_in_script), arg);
 	return arg;