diff -u b/core/lib/Drupal/Component/Utility/Settings.php b/core/lib/Drupal/Component/Utility/Settings.php
--- b/core/lib/Drupal/Component/Utility/Settings.php
+++ b/core/lib/Drupal/Component/Utility/Settings.php
@@ -1,8 +1,14 @@
 <?php
 
+/**
+ * @file
+ * Contains Drupal\Component\Utility\Settings.
+ */
+
 namespace Drupal\Component\Utility;
 
 class Settings {
+
   /**
    * @var array
    */
@@ -22,17 +28,6 @@
   }
 
   /**
-   * Trying to set a property is not allowed.
-   *
-   * @param $name
-   * @param $value
-   * @throws \Exception
-   */
-  function __set($name, $value) {
-    throw new \Exception('Nope.');
-  }
-
-  /**
    * Returns a setting.
    *
    * Settings can be set in settings.php in the $settings array and requested