diff --git a/core/core.services.yml b/core/core.services.yml
index f9449bb..d65e113 100644
--- a/core/core.services.yml
+++ b/core/core.services.yml
@@ -545,6 +545,7 @@ services:
       - { name: event_subscriber }
   route_special_attributes_subscriber:
     class: Drupal\Core\EventSubscriber\SpecialAttributesRouteSubscriber
+    arguments: ['@messenger']
     tags:
       - { name: event_subscriber }
   route_http_method_subscriber:
diff --git a/core/includes/bootstrap.inc b/core/includes/bootstrap.inc
index 5570249..cfe0810 100644
--- a/core/includes/bootstrap.inc
+++ b/core/includes/bootstrap.inc
@@ -922,7 +922,7 @@ function watchdog($type, $message, array $variables = array(), $severity = WATCH
  *   Use \Drupal::service('messenger')->addMessage() instead.
  */
 function drupal_set_message($message = NULL, $type = 'status', $repeat = FALSE) {
-  /** @var \Drupal\Core\Messenger\MessengerInterface $messenger */
+  /* @var \Drupal\Core\Messenger\MessengerInterface $messenger */
   $messenger = \Drupal::service('messenger');
   $messenger->addMessage($message, $type, $repeat);
   return $messenger->getMessages();
diff --git a/core/lib/Drupal/Core/EventSubscriber/SpecialAttributesRouteSubscriber.php b/core/lib/Drupal/Core/EventSubscriber/SpecialAttributesRouteSubscriber.php
index bf62c68..2022287 100644
--- a/core/lib/Drupal/Core/EventSubscriber/SpecialAttributesRouteSubscriber.php
+++ b/core/lib/Drupal/Core/EventSubscriber/SpecialAttributesRouteSubscriber.php
@@ -8,7 +8,7 @@
 namespace Drupal\Core\EventSubscriber;
 
 use Drupal\Component\Utility\String;
-use Drupal\Core\Messenger\MessengerTrait;
+use Drupal\Core\Messenger\MessengerInterface;
 use Drupal\Core\Routing\RouteBuildEvent;
 use Drupal\Core\Routing\RouteSubscriberBase;
 use Symfony\Cmf\Component\Routing\RouteObjectInterface;
@@ -18,7 +18,23 @@
  * Provides a route subscriber which checks for invalid pattern variables.
  */
 class SpecialAttributesRouteSubscriber extends RouteSubscriberBase {
-  use MessengerTrait;
+
+  /**
+   * The messenger service.
+   *
+   * @var \Drupal\Core\Messenger\MessengerInterface
+   */
+  protected $messenger;
+
+  /**
+   * Creates a new special attributes route subscriber.
+   *
+   * @param \Drupal\Core\Messenger\MessengerInterface $messenger
+   *   The messenger service.
+   */
+  public function __construct(MessengerInterface $messenger) {
+    $this->messenger = $messenger;
+  }
 
   /**
    * {@inheritdoc}
@@ -39,7 +55,7 @@ protected function alterRoutes(RouteCollection $collection) {
     foreach ($collection->all() as $route) {
       if ($not_allowed_variables = array_intersect($route->compile()->getVariables(), $special_variables)) {
         $placeholders = array('@variables' => implode(', ', $not_allowed_variables));
-        $this->addMessage(String::format('The following variables are reserved names by drupal: @variables', $placeholders));
+        $this->messenger->addMessage(String::format('The following variables are reserved names by drupal: @variables', $placeholders));
         watchdog('error', 'The following variables are reserved names by drupal: @variables', $placeholders);
         return FALSE;
       }
diff --git a/core/lib/Drupal/Core/Messenger/Messenger.php b/core/lib/Drupal/Core/Messenger/Messenger.php
index f7dac0b..13a5b7b 100644
--- a/core/lib/Drupal/Core/Messenger/Messenger.php
+++ b/core/lib/Drupal/Core/Messenger/Messenger.php
@@ -6,6 +6,7 @@
  */
 
 namespace Drupal\Core\Messenger;
+use Drupal\Component\Utility\SafeMarkup;
 
 /**
  * Provides a session-based messenger.
@@ -23,7 +24,10 @@ public function addMessage($message, $type = self::STATUS, $repeat = FALSE) {
       $_SESSION = array();
     }
     if ($repeat || !array_key_exists('messages', $_SESSION) || !array_key_exists($type, $_SESSION['messages']) || !in_array($message, $_SESSION['messages'][$type])) {
-      $_SESSION['messages'][$type][] = $message;
+      $_SESSION['messages'][$type][] = array(
+        'safe' => SafeMarkup::isSafe($message),
+        'message' => $message,
+      );
     }
 
     return $this;
diff --git a/core/lib/Drupal/Core/Messenger/MessengerTrait.php b/core/lib/Drupal/Core/Messenger/MessengerTrait.php
deleted file mode 100644
index 628e18e..0000000
--- a/core/lib/Drupal/Core/Messenger/MessengerTrait.php
+++ /dev/null
@@ -1,68 +0,0 @@
-<?php
-
-/**
- * @file
- * Contains \Drupal\Core\Messenger\MessengerTrait.
- */
-
-namespace Drupal\Core\Messenger;
-
-/**
- * Wrapper methods for \Drupal\Core\Messenger\Messenger.
- *
- * This utility trait should only be used in application-level code, such as
- * classes that would implement ContainerInjectionInterface. Services registered
- * in the Container should not use this trait but inject the appropriate service
- * directly for easier testing.
- */
-trait MessengerTrait {
-
-  /**
-   * The messenger service.
-   *
-   * @var \Drupal\Core\Messenger\MessengerInterface
-   */
-  protected $messenger;
-
-  /**
-   * Adds a new message to the queue.
-   *
-   * See \Drupal\Core\Messenger\MessengerInterface::addMessage() for details.
-   *
-   * @return $this
-   */
-  protected function addMessage($message, $type = MessengerInterface::STATUS, $repeat = FALSE) {
-    $this->getMessenger()->addMessage($message, $type, $repeat);
-    return $this;
-  }
-
-  /**
-   * Gets the messenger service.
-   *
-   * @return \Drupal\Core\Messenger\MessengerInterface
-   *   The messenger service.
-   */
-  protected function getMessenger() {
-    if (!$this->messenger) {
-      $this->messenger = \Drupal::service('messenger');
-    }
-
-    return $this->messenger;
-  }
-
-  /**
-   * Sets the messenger service to use.
-   *
-   * @param \Drupal\Core\Messenger\MessengerInterface $messenger
-   *   The messenger service.
-   *
-   * @return $this
-   */
-  public function setMessenger(MessengerInterface $messenger) {
-    $this->messenger = $messenger;
-
-    return $this;
-  }
-
-
-}
diff --git a/core/tests/Drupal/Tests/Core/Messenger/MessengerTraitTest.php b/core/tests/Drupal/Tests/Core/Messenger/MessengerTraitTest.php
deleted file mode 100644
index 8a7fa9c..0000000
--- a/core/tests/Drupal/Tests/Core/Messenger/MessengerTraitTest.php
+++ /dev/null
@@ -1,85 +0,0 @@
-<?php
-
-/**
- * @file
- * Contains \Drupal\Tests\Core\Messenger\MessengerTraitTest.
- */
-
-namespace Drupal\Tests\Core\Messenger;
-
-use Drupal\Core\Messenger\MessengerTrait;
-use Drupal\Tests\UnitTestCase;
-
-/**
- * @coversDefaultClass \Drupal\Core\Messenger\MessengerTrait
- */
-class MessengerTraitTest extends UnitTestCase {
-
-  /**
-   * A reflection of self::$messenger.
-   *
-   * @var \ReflectionClass
-   */
-  protected $reflection;
-
-  /**
-   * The mock under test that uses MessengerTraitTest.
-   *
-   * @var object
-   * @see PHPUnit_Framework_MockObject_Generator::getObjectForTrait()
-   */
-  protected $messengerTrait;
-
-  /**
-   * {@inheritdoc}
-   */
-  public static function getInfo() {
-    return array(
-      'name' => 'Messenger trait',
-      'description' => 'Tests the messenger trait.',
-      'group' => 'Messenger',
-    );
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function setUp() {
-    $this->messengerTrait = $this->getObjectForTrait('\Drupal\Core\Messenger\MessengerTrait');
-
-    $this->reflection = new \ReflectionClass(get_class($this->messengerTrait));
-  }
-
-  /**
-   * @covers ::addMessage
-   */
-  public function testAddMessage() {
-    $stub = $this->getMock('\Drupal\Core\Messenger\MessengerInterface');
-    $this->messengerTrait->setMessenger($stub);
-
-    $message_string = 'Beep boop';
-
-    $stub->expects($this->once())
-         ->method('addMessage')
-         ->with($this->equalTo($message_string));
-
-    $method = $this->reflection->getMethod('addMessage');
-    $method->setAccessible(TRUE);
-
-    $this->assertEquals($this->messengerTrait, $method->invoke($this->messengerTrait, $message_string));
-  }
-
-  /**
-   * @covers ::getMessenger
-   */
-  public function testGetMessenger() {
-    $stub = $this->getMock('\Drupal\Core\Messenger\MessengerInterface');
-    $this->messengerTrait->setMessenger($stub);
-
-    $method = $this->reflection->getMethod('getMessenger');
-    $method->setAccessible(TRUE);
-
-    $this->assertSame($stub, $method->invoke($this->messengerTrait));
-  }
-
-}