diff --git a/core/core.services.yml b/core/core.services.yml
index 2f3a696..380ed6e 100644
--- a/core/core.services.yml
+++ b/core/core.services.yml
@@ -1208,13 +1208,13 @@ services:
     tags:
       - { name: event_subscriber }
   account_switcher:
-    class: Drupal\Core\Session\AccountSwitcher
+    class: Drupal\Core\Authentication\AccountSwitcher
     arguments: ['@current_user', '@session_handler.write_safe']
   user_permissions_hash_generator:
     class: Drupal\Core\Session\PermissionsHashGenerator
     arguments: ['@private_key', '@cache.default']
   current_user:
-    class: Drupal\Core\Session\AccountProxy
+    class: Drupal\Core\Authentication\AccountProxy
   session_configuration:
     class: Drupal\Core\Session\SessionConfiguration
     arguments: ['%session.storage.options%']
diff --git a/core/lib/Drupal.php b/core/lib/Drupal.php
index f949669..29eca34 100644
--- a/core/lib/Drupal.php
+++ b/core/lib/Drupal.php
@@ -240,7 +240,7 @@ public static function routeMatch() {
   /**
    * Gets the current active user.
    *
-   * @return \Drupal\Core\Session\AccountProxyInterface
+   * @return \Drupal\Core\Authentication\AccountProxyInterface
    */
   public static function currentUser() {
     return static::getContainer()->get('current_user');
diff --git a/core/lib/Drupal/Core/Authentication/AccountProxyInterface.php b/core/lib/Drupal/Core/Authentication/AccountProxyInterface.php
index 2ffa241..dc24a68 100644
--- a/core/lib/Drupal/Core/Authentication/AccountProxyInterface.php
+++ b/core/lib/Drupal/Core/Authentication/AccountProxyInterface.php
@@ -21,8 +21,8 @@
    * inject the desired user object into the dependent code directly.
    *
    * A preferable method of account impersonation is to use
-   * \Drupal\Core\Session\AccountSwitcherInterface::switchTo() and
-   * \Drupal\Core\Session\AccountSwitcherInterface::switchBack().
+   * \Drupal\Core\Authentication\AccountSwitcherInterface::switchTo() and
+   * \Drupal\Core\Authentication\AccountSwitcherInterface::switchBack().
    *
    * @param \Drupal\Core\Authentication\AccountInterface $account
    *   The current account.
diff --git a/core/lib/Drupal/Core/Cache/TimeZoneCacheContext.php b/core/lib/Drupal/Core/Cache/TimeZoneCacheContext.php
index ae0621c..3362129 100644
--- a/core/lib/Drupal/Core/Cache/TimeZoneCacheContext.php
+++ b/core/lib/Drupal/Core/Cache/TimeZoneCacheContext.php
@@ -10,7 +10,7 @@
 /**
  * Defines the TimeZoneCacheContext service, for "per time zone" caching.
  *
- * @see \Drupal\Core\Session\AccountProxy::setAccount()
+ * @see \Drupal\Core\Authentication\AccountProxy::setAccount()
  */
 class TimeZoneCacheContext implements CacheContextInterface {
 
diff --git a/core/lib/Drupal/Core/Cron.php b/core/lib/Drupal/Core/Cron.php
index 615489f..1fec276 100644
--- a/core/lib/Drupal/Core/Cron.php
+++ b/core/lib/Drupal/Core/Cron.php
@@ -13,7 +13,7 @@
 use Drupal\Core\Lock\LockBackendInterface;
 use Drupal\Core\Queue\QueueFactory;
 use Drupal\Core\Authentication\AnonymousUserSession;
-use Drupal\Core\Session\AccountSwitcherInterface;
+use Drupal\Core\Authentication\AccountSwitcherInterface;
 use Drupal\Core\Queue\SuspendQueueException;
 use Psr\Log\LoggerInterface;
 
@@ -53,7 +53,7 @@ class Cron implements CronInterface {
   /**
    * The account switcher service.
    *
-   * @var \Drupal\Core\Session\AccountSwitcherInterface
+   * @var \Drupal\Core\Authentication\AccountSwitcherInterface
    */
   protected $accountSwitcher;
 
@@ -82,7 +82,7 @@ class Cron implements CronInterface {
    *   The queue service.
    * @param \Drupal\Core\State\StateInterface $state
    *   The state service.
-   * @param \Drupal\Core\Session\AccountSwitcherInterface $account_switcher
+   * @param \Drupal\Core\Authentication\AccountSwitcherInterface $account_switcher
    *    The account switching service.
    * @param \Psr\Log\LoggerInterface $logger
    *   A logger instance.
diff --git a/core/lib/Drupal/Core/EventSubscriber/AuthenticationSubscriber.php b/core/lib/Drupal/Core/EventSubscriber/AuthenticationSubscriber.php
index 6fd0b99..a62b535 100644
--- a/core/lib/Drupal/Core/EventSubscriber/AuthenticationSubscriber.php
+++ b/core/lib/Drupal/Core/EventSubscriber/AuthenticationSubscriber.php
@@ -10,7 +10,7 @@
 use Drupal\Core\Authentication\AuthenticationProviderFilterInterface;
 use Drupal\Core\Authentication\AuthenticationProviderChallengeInterface;
 use Drupal\Core\Authentication\AuthenticationProviderInterface;
-use Drupal\Core\Session\AccountProxyInterface;
+use Drupal\Core\Authentication\AccountProxyInterface;
 use Symfony\Component\EventDispatcher\EventSubscriberInterface;
 use Symfony\Component\HttpKernel\Event\GetResponseEvent;
 use Symfony\Component\HttpKernel\Event\GetResponseForExceptionEvent;
@@ -49,7 +49,7 @@ class AuthenticationSubscriber implements EventSubscriberInterface {
   /**
    * Account proxy.
    *
-   * @var \Drupal\Core\Session\AccountProxyInterface
+   * @var \Drupal\Core\Authentication\AccountProxyInterface
    */
   protected $accountProxy;
 
@@ -58,7 +58,7 @@ class AuthenticationSubscriber implements EventSubscriberInterface {
    *
    * @param \Drupal\Core\Authentication\AuthenticationProviderInterface $authentication_provider
    *   An authentication provider.
-   * @param \Drupal\Core\Session\AccountProxyInterface $account_proxy
+   * @param \Drupal\Core\Authentication\AccountProxyInterface $account_proxy
    *   Account proxy.
    */
   public function __construct(AuthenticationProviderInterface $authentication_provider, AccountProxyInterface $account_proxy) {
diff --git a/core/modules/comment/src/Tests/Views/CommentUserNameTest.php b/core/modules/comment/src/Tests/Views/CommentUserNameTest.php
index 8bc932c..3f7e4d4 100644
--- a/core/modules/comment/src/Tests/Views/CommentUserNameTest.php
+++ b/core/modules/comment/src/Tests/Views/CommentUserNameTest.php
@@ -133,7 +133,7 @@ public function testUsername() {
     ]);
     $view->save();
 
-    /* @var \Drupal\Core\Session\AccountSwitcherInterface $account_switcher */
+    /* @var \Drupal\Core\Authentication\AccountSwitcherInterface $account_switcher */
     $account_switcher = \Drupal::service('account_switcher');
 
     /* @var \Drupal\Core\Render\RendererInterface $renderer */
diff --git a/core/modules/comment/tests/src/Unit/CommentLinkBuilderTest.php b/core/modules/comment/tests/src/Unit/CommentLinkBuilderTest.php
index 202f6a4..6dc87be 100644
--- a/core/modules/comment/tests/src/Unit/CommentLinkBuilderTest.php
+++ b/core/modules/comment/tests/src/Unit/CommentLinkBuilderTest.php
@@ -44,7 +44,7 @@ class CommentLinkBuilderTest extends UnitTestCase {
   /**
    * Current user proxy mock.
    *
-   * @var \Drupal\Core\Session\AccountProxyInterface|\PHPUnit_Framework_MockObject_MockObject
+   * @var \Drupal\Core\Authentication\AccountProxyInterface|\PHPUnit_Framework_MockObject_MockObject
    */
   protected $currentUser;
 
@@ -67,7 +67,7 @@ protected function setUp() {
     $this->commentManager = $this->getMock('\Drupal\comment\CommentManagerInterface');
     $this->stringTranslation = $this->getStringTranslationStub();
     $this->moduleHandler = $this->getMock('\Drupal\Core\Extension\ModuleHandlerInterface');
-    $this->currentUser = $this->getMock('\Drupal\Core\Session\AccountProxyInterface');
+    $this->currentUser = $this->getMock('\Drupal\Core\Authentication\AccountProxyInterface');
     $this->commentLinkBuilder = new CommentLinkBuilder($this->currentUser, $this->commentManager, $this->moduleHandler, $this->stringTranslation);
     $this->commentManager->expects($this->any())
       ->method('getFields')
diff --git a/core/modules/link/src/Plugin/Validation/Constraint/LinkAccessConstraintValidator.php b/core/modules/link/src/Plugin/Validation/Constraint/LinkAccessConstraintValidator.php
index 7011ff3..a48c6f9 100644
--- a/core/modules/link/src/Plugin/Validation/Constraint/LinkAccessConstraintValidator.php
+++ b/core/modules/link/src/Plugin/Validation/Constraint/LinkAccessConstraintValidator.php
@@ -7,7 +7,7 @@
 
 namespace Drupal\link\Plugin\Validation\Constraint;
 
-use Drupal\Core\Session\AccountProxyInterface;
+use Drupal\Core\Authentication\AccountProxyInterface;
 use Drupal\Core\DependencyInjection\ContainerInjectionInterface;
 use Symfony\Component\DependencyInjection\ContainerInterface;
 use Symfony\Component\Validator\Constraint;
@@ -29,14 +29,14 @@ class LinkAccessConstraintValidator implements ConstraintValidatorInterface, Con
   /**
    * Proxy for the current user account.
    *
-   * @var \Drupal\Core\Session\AccountProxyInterface
+   * @var \Drupal\Core\Authentication\AccountProxyInterface
    */
   protected $current_user;
 
   /**
    * Constructs an instance of the LinkAccessConstraintValidator class.
    *
-   * @param \Drupal\Core\Session\AccountProxyInterface $current_user
+   * @param \Drupal\Core\Authentication\AccountProxyInterface $current_user
    *   The current user account.
    */
   public function __construct(AccountProxyInterface $current_user) {
diff --git a/core/modules/link/tests/src/Plugin/Validation/Constraint/LinkAccessConstraintValidatorTest.php b/core/modules/link/tests/src/Plugin/Validation/Constraint/LinkAccessConstraintValidatorTest.php
index a3711ec..701d824 100644
--- a/core/modules/link/tests/src/Plugin/Validation/Constraint/LinkAccessConstraintValidatorTest.php
+++ b/core/modules/link/tests/src/Plugin/Validation/Constraint/LinkAccessConstraintValidatorTest.php
@@ -26,7 +26,7 @@ class LinkAccessConstraintValidatorTest extends UnitTestCase {
    *
    * @param \Drupal\link\LinkItemInterface $value
    *   The link item.
-   * @param \Drupal\Core\Session\AccountProxyInterface $user
+   * @param \Drupal\Core\Authentication\AccountProxyInterface $user
    *   The user account.
    * @param bool $valid
    *   A boolean indicating if the combination is expected to be valid.
@@ -86,7 +86,7 @@ public function providerValidate() {
         ->willReturn($url);
       // Mock a user object that returns a boolean indicating user access to all
       // links.
-      $user = $this->getMock('Drupal\Core\Session\AccountProxyInterface');
+      $user = $this->getMock('Drupal\Core\Authentication\AccountProxyInterface');
       $user->expects($this->any())
         ->method('hasPermission')
         ->with($this->equalTo('link to any page'))
diff --git a/core/modules/simpletest/src/TestBase.php b/core/modules/simpletest/src/TestBase.php
index 7f60ecc..6a506f5 100644
--- a/core/modules/simpletest/src/TestBase.php
+++ b/core/modules/simpletest/src/TestBase.php
@@ -17,8 +17,6 @@
 use Drupal\Core\Database\ConnectionNotDefinedException;
 use Drupal\Core\Config\StorageInterface;
 use Drupal\Core\Language\Language;
-use Drupal\Core\Session\AccountProxy;
-use Drupal\Core\Authentication\AnonymousUserSession;
 use Drupal\Core\Site\Settings;
 use Drupal\Core\StreamWrapper\PublicStream;
 use Drupal\Core\Utility\Error;
@@ -217,7 +215,7 @@
   /**
    * The original user, before testing began.
    *
-   * @var \Drupal\Core\Session\AccountProxyInterface
+   * @var \Drupal\Core\Authentication\AccountProxyInterface
    */
   protected $originalUser;
 
diff --git a/core/modules/system/core.api.php b/core/modules/system/core.api.php
index 304652b..f4eed23 100644
--- a/core/modules/system/core.api.php
+++ b/core/modules/system/core.api.php
@@ -635,7 +635,7 @@
  * - \Drupal\Core\Authentication\AccountInterface: The part of UserInterface that
  *   deals with access checking. In writing code that checks access, your
  *   method parameters should use this interface, not UserInterface.
- * - \Drupal\Core\Session\AccountProxyInterface: The interface for the
+ * - \Drupal\Core\Authentication\AccountProxyInterface: The interface for the
  *   current_user service (described above).
  * @}
  */
diff --git a/core/modules/user/src/Plugin/Validation/Constraint/ProtectedUserFieldConstraintValidator.php b/core/modules/user/src/Plugin/Validation/Constraint/ProtectedUserFieldConstraintValidator.php
index d99fc5d..68c5cb1 100644
--- a/core/modules/user/src/Plugin/Validation/Constraint/ProtectedUserFieldConstraintValidator.php
+++ b/core/modules/user/src/Plugin/Validation/Constraint/ProtectedUserFieldConstraintValidator.php
@@ -7,7 +7,7 @@
 namespace Drupal\user\Plugin\Validation\Constraint;
 
 use Drupal\Core\DependencyInjection\ContainerInjectionInterface;
-use Drupal\Core\Session\AccountProxyInterface;
+use Drupal\Core\Authentication\AccountProxyInterface;
 use Drupal\user\UserStorageInterface;
 use Symfony\Component\DependencyInjection\ContainerInterface;
 use Symfony\Component\Validator\Constraint;
@@ -28,7 +28,7 @@ class ProtectedUserFieldConstraintValidator extends ConstraintValidator implemen
   /**
    * The current user.
    *
-   * @var \Drupal\Core\Session\AccountProxyInterface
+   * @var \Drupal\Core\Authentication\AccountProxyInterface
    */
   protected $currentUser;
 
@@ -37,7 +37,7 @@ class ProtectedUserFieldConstraintValidator extends ConstraintValidator implemen
    *
    * @param \Drupal\user\UserStorageInterface $user_storage
    *   The user storage handler.
-   * @param \Drupal\Core\Session\AccountProxyInterface $current_user
+   * @param \Drupal\Core\Authentication\AccountProxyInterface $current_user
    *   The current user.
    */
   public function __construct(UserStorageInterface $user_storage, AccountProxyInterface $current_user) {
diff --git a/core/modules/user/src/PrivateTempStore.php b/core/modules/user/src/PrivateTempStore.php
index 79be710..4f00bf4 100644
--- a/core/modules/user/src/PrivateTempStore.php
+++ b/core/modules/user/src/PrivateTempStore.php
@@ -10,7 +10,7 @@
 use Drupal\Component\Utility\SafeMarkup;
 use Drupal\Core\KeyValueStore\KeyValueStoreExpirableInterface;
 use Drupal\Core\Lock\LockBackendInterface;
-use Drupal\Core\Session\AccountProxyInterface;
+use Drupal\Core\Authentication\AccountProxyInterface;
 use Symfony\Component\HttpFoundation\RequestStack;
 
 /**
@@ -51,7 +51,7 @@ class PrivateTempStore {
   /**
    * The current user.
    *
-   * @var \Drupal\Core\Session\AccountProxyInterface
+   * @var \Drupal\Core\Authentication\AccountProxyInterface
    */
   protected $currentUser;
 
diff --git a/core/modules/user/src/PrivateTempStoreFactory.php b/core/modules/user/src/PrivateTempStoreFactory.php
index bd62633..d438aba 100644
--- a/core/modules/user/src/PrivateTempStoreFactory.php
+++ b/core/modules/user/src/PrivateTempStoreFactory.php
@@ -9,7 +9,7 @@
 
 use Drupal\Core\KeyValueStore\KeyValueExpirableFactoryInterface;
 use Drupal\Core\Lock\LockBackendInterface;
-use Drupal\Core\Session\AccountProxyInterface;
+use Drupal\Core\Authentication\AccountProxyInterface;
 use Symfony\Component\HttpFoundation\RequestStack;
 
 /**
@@ -34,7 +34,7 @@ class PrivateTempStoreFactory {
   /**
    * The current user.
    *
-   * @var \Drupal\Core\Session\AccountProxyInterface
+   * @var \Drupal\Core\Authentication\AccountProxyInterface
    */
   protected $currentUser;
 
diff --git a/core/modules/user/tests/src/Unit/Plugin/Validation/Constraint/ProtectedUserFieldConstraintValidatorTest.php b/core/modules/user/tests/src/Unit/Plugin/Validation/Constraint/ProtectedUserFieldConstraintValidatorTest.php
index e0c068e..e7b754f 100644
--- a/core/modules/user/tests/src/Unit/Plugin/Validation/Constraint/ProtectedUserFieldConstraintValidatorTest.php
+++ b/core/modules/user/tests/src/Unit/Plugin/Validation/Constraint/ProtectedUserFieldConstraintValidatorTest.php
@@ -35,7 +35,7 @@ protected function createValidator() {
     $user_storage->expects($this->any())
       ->method('loadUnchanged')
       ->willReturn($unchanged_account);
-    $current_user = $this->getMock('Drupal\Core\Session\AccountProxyInterface');
+    $current_user = $this->getMock('Drupal\Core\Authentication\AccountProxyInterface');
     $current_user->expects($this->any())
       ->method('id')
       ->willReturn('current-user');
diff --git a/core/modules/user/tests/src/Unit/PrivateTempStoreTest.php b/core/modules/user/tests/src/Unit/PrivateTempStoreTest.php
index a2d3d95..6fe6765 100644
--- a/core/modules/user/tests/src/Unit/PrivateTempStoreTest.php
+++ b/core/modules/user/tests/src/Unit/PrivateTempStoreTest.php
@@ -42,7 +42,7 @@ class PrivateTempStoreTest extends UnitTestCase {
   /**
    * The current user.
    *
-   * @var \Drupal\Core\Session\AccountProxyInterface|\PHPUnit_Framework_MockObject_MockObject
+   * @var \Drupal\Core\Authentication\AccountProxyInterface|\PHPUnit_Framework_MockObject_MockObject
    */
   protected $currentUser;
 
@@ -75,7 +75,7 @@ protected function setUp() {
 
     $this->keyValue = $this->getMock('Drupal\Core\KeyValueStore\KeyValueStoreExpirableInterface');
     $this->lock = $this->getMock('Drupal\Core\Lock\LockBackendInterface');
-    $this->currentUser = $this->getMock('Drupal\Core\Session\AccountProxyInterface');
+    $this->currentUser = $this->getMock('Drupal\Core\Authentication\AccountProxyInterface');
     $this->currentUser->expects($this->any())
       ->method('id')
       ->willReturn(1);
diff --git a/core/modules/views/src/Tests/Handler/FieldFieldAccessTestBase.php b/core/modules/views/src/Tests/Handler/FieldFieldAccessTestBase.php
index 5554a8a..08ccff4 100644
--- a/core/modules/views/src/Tests/Handler/FieldFieldAccessTestBase.php
+++ b/core/modules/views/src/Tests/Handler/FieldFieldAccessTestBase.php
@@ -116,7 +116,7 @@ protected function assertFieldAccess($entity_type_id, $field_name, $field_conten
     ]);
     $entity->save();
 
-    /** @var \Drupal\Core\Session\AccountSwitcherInterface $account_switcher */
+    /** @var \Drupal\Core\Authentication\AccountSwitcherInterface $account_switcher */
     $account_switcher = \Drupal::service('account_switcher');
 
     /** @var \Drupal\Core\Render\RendererInterface $renderer */