diff --git a/core/modules/node/src/Form/DeleteMultiple.php b/core/modules/node/src/Form/DeleteMultiple.php
index a5686dc..68923ac 100644
--- a/core/modules/node/src/Form/DeleteMultiple.php
+++ b/core/modules/node/src/Form/DeleteMultiple.php
@@ -97,8 +97,11 @@ public function getConfirmText() {
    * {@inheritdoc}
    */
   public function buildForm(array $form, FormStateInterface $form_state) {
-    $this->nodes = $this->tempStoreFactory->get('node_multiple_delete_confirm')->get(\Drupal::currentUser()->id());
+    $current_user_id = $this->currentUser()->id();
+    $node_temp_store = $this->tempStoreFactory->get('node_multiple_delete_confirm');
+    $this->nodes = $node_temp_store->get($current_user_id);
     if (empty($this->nodes)) {
+      $node_temp_store->delete($current_user_id);
       throw new AccessDeniedHttpException();
     }
 
diff --git a/core/modules/simpletest/src/Form/SimpletestResultsForm.php b/core/modules/simpletest/src/Form/SimpletestResultsForm.php
index 7d39496..e2798b1 100644
--- a/core/modules/simpletest/src/Form/SimpletestResultsForm.php
+++ b/core/modules/simpletest/src/Form/SimpletestResultsForm.php
@@ -15,7 +15,6 @@
 use Drupal\Core\Url;
 use Drupal\simpletest\TestDiscovery;
 use Symfony\Component\DependencyInjection\ContainerInterface;
-use Symfony\Component\HttpFoundation\RedirectResponse;
 
 /**
  * Test results form for $test_id.
@@ -114,7 +113,7 @@ public function buildForm(array $form, FormStateInterface $form_state, $test_id
 
     if (is_numeric($test_id) && !$results = $this->getResults($test_id)) {
       drupal_set_message($this->t('No test results to display.'), 'error');
-      return new RedirectResponse($this->url('simpletest.test_form', array(), array('absolute' => TRUE)));
+      return $this->redirect('simpletest.test_form');
     }
 
     // Load all classes and include CSS.
diff --git a/core/modules/simpletest/src/Tests/SimpleTestTest.php b/core/modules/simpletest/src/Tests/SimpleTestTest.php
index d2949a6..278e2f1 100644
--- a/core/modules/simpletest/src/Tests/SimpleTestTest.php
+++ b/core/modules/simpletest/src/Tests/SimpleTestTest.php
@@ -129,6 +129,10 @@ function testWebTestRunner() {
       // Regression test for #290316.
       // Check that test_id is incrementing.
       $this->assertTrue($this->test_ids[0] != $this->test_ids[1], 'Test ID is incrementing.');
+
+      // Attempt to retrieve results for a non-existent test run ID.
+      $this->drupalGet('admin/config/development/testing/results/' . ($this->test_ids[1] + 1));
+      $this->assertRaw('No test results to display');
     }
   }
 
diff --git a/core/modules/system/src/Form/CronForm.php b/core/modules/system/src/Form/CronForm.php
index cfb82fd..5956c34 100644
--- a/core/modules/system/src/Form/CronForm.php
+++ b/core/modules/system/src/Form/CronForm.php
@@ -14,7 +14,6 @@
 use Drupal\Core\State\StateInterface;
 use Drupal\Core\Form\ConfigFormBase;
 use Symfony\Component\DependencyInjection\ContainerInterface;
-use Symfony\Component\HttpFoundation\RedirectResponse;
 
 /**
  * Configure cron settings for this site.
@@ -144,7 +143,7 @@ public function submitCron(array &$form, FormStateInterface $form_state) {
       drupal_set_message(t('Cron run failed.'), 'error');
     }
 
-    return new RedirectResponse($this->url('system.cron_settings', array(), array('absolute' => TRUE)));
+    return $this->redirect('system.cron_settings');
   }
 
 }
diff --git a/core/modules/user/src/Form/UserMultipleCancelConfirm.php b/core/modules/user/src/Form/UserMultipleCancelConfirm.php
index 45f340f..17ec9fb 100644
--- a/core/modules/user/src/Form/UserMultipleCancelConfirm.php
+++ b/core/modules/user/src/Form/UserMultipleCancelConfirm.php
@@ -15,6 +15,7 @@
 use Drupal\user\TempStoreFactory;
 use Drupal\user\UserStorageInterface;
 use Symfony\Component\DependencyInjection\ContainerInterface;
+use Symfony\Component\HttpKernel\Exception\AccessDeniedHttpException;
 
 /**
  * Provides a confirmation form for cancelling multiple user accounts.
@@ -101,12 +102,13 @@ public function getConfirmText() {
    * {@inheritdoc}
    */
   public function buildForm(array $form, FormStateInterface $form_state) {
+    $current_user_id = $this->currentUser()->id();
+    $user_temp_store = $this->tempStoreFactory->get('user_user_operations_cancel');
     // Retrieve the accounts to be canceled from the temp store.
-    $accounts = $this->tempStoreFactory
-      ->get('user_user_operations_cancel')
-      ->get($this->currentUser()->id());
+    $accounts = $user_temp_store->get($current_user_id);
     if (!$accounts) {
-      return $this->redirect('user.admin_account');
+      $user_temp_store->delete($current_user_id);
+      throw new AccessDeniedHttpException();
     }
 
     $form['accounts'] = array('#prefix' => '<ul>', '#suffix' => '</ul>', '#tree' => TRUE);
@@ -130,6 +132,7 @@ public function buildForm(array $form, FormStateInterface $form_state) {
       drupal_set_message($message, $redirect ? 'error' : 'warning');
       // If only user 1 was selected, redirect to the overview.
       if ($redirect) {
+        $user_temp_store->delete($current_user_id);
         return $this->redirect('user.admin_account');
       }
     }
diff --git a/core/modules/user/src/Tests/UserCancelTest.php b/core/modules/user/src/Tests/UserCancelTest.php
index de3d1ae..9f39078 100644
--- a/core/modules/user/src/Tests/UserCancelTest.php
+++ b/core/modules/user/src/Tests/UserCancelTest.php
@@ -92,9 +92,10 @@ function testUserCancelUid1() {
     $this->drupalLogin($this->admin_user);
     $edit = array(
       'action' => 'user_cancel_user_action',
-      'user_bulk_form[0]' => TRUE,
+      'user_bulk_form[1]' => TRUE,
     );
     $this->drupalPostForm('admin/people', $edit, t('Apply'));
+    $this->assertResponse(200);
 
     // Verify that uid 1's account was not cancelled.
     $user1 = user_load(1, TRUE);
@@ -141,6 +142,10 @@ function testUserCancelInvalid() {
     // Confirm user's content has not been altered.
     $test_node = node_load($node->id(), TRUE);
     $this->assertTrue(($test_node->getOwnerId() == $account->id() && $test_node->isPublished()), 'Node of the user has not been altered.');
+
+    // Attempt to visit the bulk user cancel page without selecting users.
+    $this->drupalGet('admin/people/cancel');
+    $this->assertResponse(403);
   }
 
   /**
diff --git a/core/modules/views_ui/src/Form/Ajax/ViewsFormBase.php b/core/modules/views_ui/src/Form/Ajax/ViewsFormBase.php
index 6d558cd..809abb7 100644
--- a/core/modules/views_ui/src/Form/Ajax/ViewsFormBase.php
+++ b/core/modules/views_ui/src/Form/Ajax/ViewsFormBase.php
@@ -15,7 +15,6 @@
 use Drupal\views\Ajax;
 use Drupal\Core\Ajax\AjaxResponse;
 use Drupal\Core\Ajax\CloseModalDialogCommand;
-use Symfony\Component\HttpFoundation\RedirectResponse;
 
 /**
  * Provides a base class for Views UI AJAX forms.
@@ -149,7 +148,7 @@ public function getForm(ViewStorageInterface $view, $display_id, $js) {
       $form_state->setUserInput(array());
       $form_path = views_ui_build_form_path($form_state);
       if (!$form_state->get('ajax')) {
-        return new RedirectResponse(_url($form_path, array('absolute' => TRUE)));
+        return $this->redirect(_url($form_path));
       }
       $form_state->set('path', $form_path);
       $response = views_ajax_form_wrapper($form_class, $form_state);
@@ -157,7 +156,7 @@ public function getForm(ViewStorageInterface $view, $display_id, $js) {
     elseif (!$form_state->get('ajax')) {
       // if nothing on the stack, non-js forms just go back to the main view editor.
       $display_id = $form_state->get('display_id');
-      return new RedirectResponse($this->url('entity.view.edit_display_form', ['view' => $view->id(), 'display_id' => $display_id], ['absolute' => TRUE]));
+      return $this->redirect('entity.view.edit_display_form', ['view' => $view->id(), 'display_id' => $display_id]);
     }
     else {
       $response = new AjaxResponse();