diff --git a/src/userfunc.c b/src/userfunc.c
index e496bce..2e93f3e 100644
--- a/src/userfunc.c
+++ b/src/userfunc.c
@@ -570,7 +570,7 @@
 					    &varargs, NULL, FALSE, NULL, NULL);
     if (ret == FAIL
 		  || (s = skip_arrow(*arg, equal_arrow, &ret_type,
-				   equal_arrow ? &white_error : NULL)) == NULL)
+		equal_arrow || in_vim9script() ? &white_error : NULL)) == NULL)
     {
 	if (types_optional)
 	    ga_clear_strings(&argtypes);