diff --git a/core/modules/user/lib/Drupal/user/AccountFormController.php b/core/modules/user/lib/Drupal/user/AccountFormController.php
index 6002298..2f91f60 100644
--- a/core/modules/user/lib/Drupal/user/AccountFormController.php
+++ b/core/modules/user/lib/Drupal/user/AccountFormController.php
@@ -308,9 +308,13 @@ public function validate(array $form, array &$form_state) {
     parent::validate($form, $form_state);
 
     $account = $this->entity;
+    $mail = $form_state['values']['mail'];
+
     // Validate new or changing username.
     if (isset($form_state['values']['name'])) {
-      if ($error = user_validate_name($form_state['values']['name'])) {
+      $name = $form_state['values']['name'];
+
+      if ($error = user_validate_name($name)) {
         $this->setFormError('name', $form_state, $error);
       }
       // Cast the user ID as an integer. It might have been set to NULL, which
@@ -318,19 +322,23 @@ public function validate(array $form, array &$form_state) {
       else {
         $name_taken = (bool) $this->entityQuery->get('user')
           ->condition('uid', (int) $account->id(), '<>')
-          ->condition('name', $form_state['values']['name'])
+          ->condition('name', $name)
           ->range(0, 1)
           ->count()
           ->execute();
 
         if ($name_taken) {
-          $this->setFormError('name', $form_state, $this->t('The name %name is already taken.', array('%name' => $form_state['values']['name'])));
+          $this->setFormError('name', $form_state, $this->t('The name %name is already taken.', array('%name' => $name)));
+        }
+
+        // Check whether the user name provided is an email address, if so, make
+        // sure it matches the mail value.
+        if (filter_var($name, FILTER_VALIDATE_EMAIL) && ($name !== $mail)) {
+          $this->setFormError('name', $form_state, $this->t('If your username is an email address, it must match your email.'));
         }
       }
     }
 
-    $mail = $form_state['values']['mail'];
-
     if (!empty($mail)) {
       $mail_taken = (bool) $this->entityQuery->get('user')
         ->condition('uid', (int) $account->id(), '<>')
diff --git a/core/modules/user/lib/Drupal/user/Tests/UserEditedOwnAccountTest.php b/core/modules/user/lib/Drupal/user/Tests/UserEditedOwnAccountTest.php
index 50f1081b..7726168 100644
--- a/core/modules/user/lib/Drupal/user/Tests/UserEditedOwnAccountTest.php
+++ b/core/modules/user/lib/Drupal/user/Tests/UserEditedOwnAccountTest.php
@@ -47,14 +47,15 @@ function testUserEditedOwnAccount() {
     $edit['name'] = $this->randomName() . '@example.com';
     $this->drupalPostForm('user/' . $account->id() . '/edit', $edit, t('Save'));
     $this->assertText(t('If your username is an email address, it must match your email.'), 'Error message found when an email username does not match user email.');
+    $this->assertNoText(t('The changes have been saved.'), 'The user account was not saved.');
 
     // Lookup user by name to make sure we didn't actually change the name.
-    $accounts = entity_load_multiple_by_properties('user', array('name' => $edit['name']));
+    $accounts = \Drupal::entityManager()->getStorageController('user')->loadByProperties(array('name' => $edit['name']));
     $this->assertTrue(empty($accounts), 'Username was not changed to email address other than my own.');
 
     // Change username to my email address.
     $edit['name'] = $account->getEmail();
     $this->drupalPostForm('user/' . $account->id() . '/edit', $edit, t('Save'));
-
+    $this->assertText(t('The changes have been saved.'), 'The user account was saved.');
   }
 }
diff --git a/core/modules/user/lib/Drupal/user/Tests/UserRegistrationTest.php b/core/modules/user/lib/Drupal/user/Tests/UserRegistrationTest.php
index b7ce21f..240eb53 100644
--- a/core/modules/user/lib/Drupal/user/Tests/UserRegistrationTest.php
+++ b/core/modules/user/lib/Drupal/user/Tests/UserRegistrationTest.php
@@ -175,12 +175,14 @@ function testRegistrationEmailAsUsername() {
     $this->drupalPostForm('user/register', $edit, t('Create new account'));
     $this->assertText(t('If your username is an email address, it must match your email.'), 'Email username does not match user email error message found.');
     $this->assertNoText(t('Registration successful. You are now logged in.'), 'The user was not created and logged in.');
-    $this->drupalLogout();
 
     // Attempt to create new account using matching email address.
     $edit['name'] = $edit['mail'] = $this->randomName() . '@example.com';
+
     $this->drupalPostForm('user/register', $edit, t('Create new account'));
-    $accounts = entity_load_multiple_by_properties('user', array('name' => $edit['name']));
+    $this->assertText(t('Registration successful. You are now logged in.'), 'The user was created and logged in with matching email.');
+
+    $accounts = \Drupal::entityManager()->getStorageController('user')->loadByProperties(array('name' => $edit['name']));
     $new_user = reset($accounts);
     $this->assertTrue(($new_user->getUsername() === $edit['name']) && ($new_user->getEmail() === $edit['mail']), 'Created user with matching username and email address.');