diff --git a/src/wp-includes/class-wp-comment-query.php b/src/wp-includes/class-wp-comment-query.php
index 25b7fcf1a8..42c5bd1e94 100644
--- a/src/wp-includes/class-wp-comment-query.php
+++ b/src/wp-includes/class-wp-comment-query.php
@@ -935,6 +935,8 @@ class WP_Comment_Query {
 	 * the descendant trees for all matched top-level comments.
 	 *
 	 * @since 4.4.0
+	 * 
+	 * @global wpdb $wpdb WordPress database abstraction object.
 	 *
 	 * @param array $comments Array of top-level comments whose descendants should be filled in.
 	 * @return array