diff --git a/src/dict.c b/src/dict.c
index 5581a55..051ba2f 100644
--- a/src/dict.c
+++ b/src/dict.c
@@ -951,6 +951,11 @@
 	}
 	if (evaluate)
 	{
+	    if (vim9script && check_for_string(&tvkey) == FAIL)
+	    {
+		clear_tv(&tvkey);
+		goto failret;
+	    }
 	    key = tv_get_string_buf_chk(&tvkey, buf);
 	    if (key == NULL)
 	    {