Index: src/wp-includes/category.php
===================================================================
--- src/wp-includes/category.php	(revision 47928)
+++ src/wp-includes/category.php	(working copy)
@@ -283,7 +283,8 @@
  * @see get_terms() For list of arguments to pass.
  *
  * @param string|array $args Tag arguments to use when retrieving tags.
- * @return WP_Term[]|int $tags Array of 'post_tag' term objects, or a count thereof.
+ * @return WP_Term[]|int|WP_Error $tags Array of 'post_tag' term objects, a count thereof, or WP_Error if any
+ *                                      explicitly specified taxonomies do not exist.
  */
 function get_tags( $args = '' ) {
 	$defaults = array( 'taxonomy' => 'post_tag' );