diff --git a/core/core.services.yml b/core/core.services.yml
index 69adbd8..1f27366 100644
--- a/core/core.services.yml
+++ b/core/core.services.yml
@@ -753,10 +753,12 @@ services:
     class: Drupal\Core\Path\PathValidator
     arguments: ['@router', '@router.no_access_checks', '@current_user', '@path_processor_manager']
 
-# The first argument of the hashing service (constructor of PhpPassword) is the
-# 'cost' option of password_hash().
-# @todo increase by 1 every Drupal version in order to counteract increases in
-# the speed and power of computers available to crack the hashes.
+  # The first argument of the hashing service (constructor of PhpPassword) is
+  # the 'cost' option of password_hash(). In Drupal 8 the 'cost' has the default
+  # value used by password_hash() which is 10. Future versions of Drupal may
+  # increase this value in order to counteract increases in the speed and power
+  # of computers available to crack the hashes. Note that an increase of 1 will
+  # double the time needed for password hashing.
   password:
     class: Drupal\Core\Password\PhpPassword
     arguments: ['%password_hash_cost%', '@drupal7_password']
diff --git a/core/lib/Drupal/Core/Password/PasswordInterface.php b/core/lib/Drupal/Core/Password/PasswordInterface.php
index 9726f69..40b9658 100644
--- a/core/lib/Drupal/Core/Password/PasswordInterface.php
+++ b/core/lib/Drupal/Core/Password/PasswordInterface.php
@@ -15,6 +15,11 @@
 interface PasswordInterface {
 
   /**
+   * Maximum password length.
+   */
+  const PASSWORD_MAX_LENGTH = 512;
+
+  /**
    * Hash a password using a secure hash.
    *
    * @param string $password
diff --git a/core/lib/Drupal/Core/Password/PhpPassword.php b/core/lib/Drupal/Core/Password/PhpPassword.php
index 35036e4..f271d81 100644
--- a/core/lib/Drupal/Core/Password/PhpPassword.php
+++ b/core/lib/Drupal/Core/Password/PhpPassword.php
@@ -25,11 +25,6 @@
 class PhpPassword implements PasswordInterface {
 
   /**
-   * Maximum password length.
-   */
-  const PASSWORD_MAX_LENGTH = 512;
-
-  /**
    * The algorithmic cost that should be used.
    *
    * @var int
@@ -94,7 +89,7 @@ public function check($password, UserInterface $account) {
    */
   public function userNeedsNewHash(UserInterface $account) {
     // The PHP 5.5 password_needs_rehash() will return TRUE in two cases:
-    // - The the password is a Drupal 6 or 7 password and it has been rehashed
+    // - The password is a Drupal 6 or 7 password and it has been rehashed
     //   during the migration. In this case the rehashed legacy hash is prefixed
     //   to indicate and old-Drupal hash and will not comply with the expected
     //   password_needs_rehash() format.
diff --git a/core/modules/simpletest/src/KernelTestBase.php b/core/modules/simpletest/src/KernelTestBase.php
index 8ffd3dd..0615020 100644
--- a/core/modules/simpletest/src/KernelTestBase.php
+++ b/core/modules/simpletest/src/KernelTestBase.php
@@ -15,7 +15,6 @@
 use Drupal\Core\Entity\Sql\SqlEntityStorageInterface;
 use Drupal\Core\KeyValueStore\KeyValueMemoryFactory;
 use Drupal\Core\Language\Language;
-use Drupal\Core\Password\PhpassHashedPassword;
 use Drupal\Core\Site\Settings;
 use Symfony\Component\DependencyInjection\Parameter;
 use Drupal\Core\StreamWrapper\StreamWrapperInterface;
diff --git a/core/modules/user/src/Tests/UserLoginTest.php b/core/modules/user/src/Tests/UserLoginTest.php
index 8628780..9546b70 100644
--- a/core/modules/user/src/Tests/UserLoginTest.php
+++ b/core/modules/user/src/Tests/UserLoginTest.php
@@ -8,7 +8,6 @@
 namespace Drupal\user\Tests;
 
 use Drupal\simpletest\WebTestBase;
-use Drupal\user\Entity\User;
 use Drupal\user\UserInterface;
 
 /**