diff --git a/src/vim9cmds.c b/src/vim9cmds.c
index 6295090..d4ffb93 100644
--- a/src/vim9cmds.c
+++ b/src/vim9cmds.c
@@ -99,7 +99,7 @@
     if (name[1] != ':' || vim_strchr((char_u *)"gwtb", *name) == NULL)
     {
 	// "unlet s:var" is allowed in legacy script.
-	if (*name == 's' && !script_is_vim9())
+	if (*name == 's' && !in_vim9script())
 	    return OK;
 	semsg(_(e_cannot_unlet_str), name);
 	return FAIL;