diff --git a/src/eval.c b/src/eval.c
index 6522f0f..f5fd3e0 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -5298,6 +5298,9 @@
 	return &pos;
     }
 
+    if (in_vim9script() && check_for_string_arg(varp, 0) == FAIL)
+	return NULL;
+
     name = tv_get_string_chk(varp);
     if (name == NULL)
 	return NULL;