diff --git a/core/modules/user/user.module b/core/modules/user/user.module
index 4219728..b26bf48 100644
--- a/core/modules/user/user.module
+++ b/core/modules/user/user.module
@@ -1208,7 +1208,7 @@ function user_preprocess_block(&$variables) {
  *   this result must ensure that check_plain() is called on it before it is
  *   printed to the page.
  */
-function user_format_name($account) {
+function user_format_name(User $account) {
   $name = !empty($account->name) ? $account->name : variable_get('anonymous', t('Anonymous'));
   drupal_alter('user_format_name', $name, $account);
   return $name;