Index: src/wp-includes/class-wp-comment-query.php
===================================================================
--- src/wp-includes/class-wp-comment-query.php	(revision 38113)
+++ src/wp-includes/class-wp-comment-query.php	(working copy)
@@ -151,6 +151,7 @@
 	 * @since 4.4.0 Order by `comment__in` was added. `$update_comment_meta_cache`, `$no_found_rows`,
 	 *              `$hierarchical`, and `$update_comment_post_cache` were added.
 	 * @since 4.5.0 Introduced the `$author_url` argument.
+	 * @since 4.6.0 Introduced the `$cache_domain` argument.
 	 * @access public
 	 *
 	 * @param string|array $query {
@@ -254,6 +255,8 @@
 	 *                                                   Default true.
 	 *     @type bool         $update_comment_post_cache Whether to prime the cache for comment posts.
 	 *                                                   Default false.
+ 	 *     @type string       $cache_domain              Unique cache key to be produced when this query is stored in
+	 *                                                   an object cache. Default is 'core'.
 	 * }
 	 */
 	public function __construct( $query = '' ) {
@@ -301,6 +304,7 @@
 			'hierarchical' => false,
 			'update_comment_meta_cache' => true,
 			'update_comment_post_cache' => false,
+			'cache_domain' => 'core',
 		);
 
 		if ( ! empty( $query ) ) {