diff --git a/core/modules/system/lib/Drupal/system/SystemManager.php b/core/modules/system/lib/Drupal/system/SystemManager.php
index 00714b2..2712169 100644
--- a/core/modules/system/lib/Drupal/system/SystemManager.php
+++ b/core/modules/system/lib/Drupal/system/SystemManager.php
@@ -60,7 +60,7 @@ public function __construct(ModuleHandlerInterface $module_handler, Connection $
    */
   public function checkRequirements() {
     $requirements = $this->listRequirements();
-    return $this->getMaxSeverity($requirements) == REQUIREMENT_ERROR;
+    return $this->getMaxSeverity($requirements) == static::REQUIREMENT_ERROR;
   }
 
   /**
@@ -90,6 +90,8 @@ public function listRequirements() {
   }
 
   /**
+   * Fixes anonymous user on MySQL.
+   *
    * MySQL import might have set the uid of the anonymous user to autoincrement
    * value. Let's try fixing it. See http://drupal.org/node/204411
    */
@@ -113,7 +115,7 @@ public function fixAnonymousUid() {
    *   The highest severity in the array.
    */
   public function getMaxSeverity(&$requirements) {
-    $severity = REQUIREMENT_OK;
+    $severity = static::REQUIREMENT_OK;
     foreach ($requirements as $requirement) {
       if (isset($requirement['severity'])) {
         $severity = max($severity, $requirement['severity']);