diff --git a/core/modules/comment/comment.module b/core/modules/comment/comment.module
index 08e938d..14254a2 100644
--- a/core/modules/comment/comment.module
+++ b/core/modules/comment/comment.module
@@ -127,11 +127,6 @@ function comment_entity_extra_field_info() {
           'description' => t('Author textfield'),
           'weight' => -2,
         ),
-        'subject' => array(
-          'label' => t('Subject'),
-          'description' => t('Subject textfield'),
-          'weight' => -1,
-        ),
       ),
     );
   }
diff --git a/core/modules/comment/config/schema/comment.schema.yml b/core/modules/comment/config/schema/comment.schema.yml
index 7a51d4f..59900c1 100644
--- a/core/modules/comment/config/schema/comment.schema.yml
+++ b/core/modules/comment/config/schema/comment.schema.yml
@@ -106,9 +106,6 @@ field.comment.instance_settings:
     anonymous:
       type: integer
       label: 'Mode'
-    subject:
-      type: boolean
-      label: 'Allow comment title'
     form_location:
       type: boolean
       label: ' Allow comment title'
diff --git a/core/modules/comment/src/CommentForm.php b/core/modules/comment/src/CommentForm.php
index 27d4a93..420ecfe 100644
--- a/core/modules/comment/src/CommentForm.php
+++ b/core/modules/comment/src/CommentForm.php
@@ -206,14 +206,6 @@ public function form(array $form, array &$form_state) {
       '#access' => $is_admin,
     );
 
-    $form['subject'] = array(
-      '#type' => 'textfield',
-      '#title' => $this->t('Subject'),
-      '#maxlength' => 64,
-      '#default_value' => $comment->getSubject(),
-      '#access' => $field_definition->getSetting('subject'),
-    );
-
     // Used for conditional validation of author fields.
     $form['is_anonymous'] = array(
       '#type' => 'value',
diff --git a/core/modules/comment/src/Entity/Comment.php b/core/modules/comment/src/Entity/Comment.php
index 1164756..990dedb 100644
--- a/core/modules/comment/src/Entity/Comment.php
+++ b/core/modules/comment/src/Entity/Comment.php
@@ -227,8 +227,13 @@ public static function baseFieldDefinitions(EntityTypeInterface $entity_type) {
 
     $fields['subject'] = FieldDefinition::create('string')
       ->setLabel(t('Subject'))
-      ->setDescription(t('The comment title or subject.'))
-      ->setSetting('max_length', 64);
+      ->setSetting('max_length', 64)
+      ->setDisplayOptions('form', array(
+        'type' => 'string',
+        // Default comment body field has weight 20.
+        'weight' => 10,
+      ))
+      ->setDisplayConfigurable('form', TRUE);
 
     $fields['uid'] = FieldDefinition::create('entity_reference')
       ->setLabel(t('User ID'))
diff --git a/core/modules/comment/src/Plugin/Field/FieldType/CommentItem.php b/core/modules/comment/src/Plugin/Field/FieldType/CommentItem.php
index 7fb70aa..35d5c0f 100644
--- a/core/modules/comment/src/Plugin/Field/FieldType/CommentItem.php
+++ b/core/modules/comment/src/Plugin/Field/FieldType/CommentItem.php
@@ -44,7 +44,6 @@ public static function defaultInstanceSettings() {
       'per_page' => 50,
       'form_location' => COMMENT_FORM_BELOW,
       'anonymous' => COMMENT_ANONYMOUS_MAYNOT_CONTACT,
-      'subject' => 1,
       'preview' => DRUPAL_OPTIONAL,
     ) + parent::defaultInstanceSettings();
   }
@@ -142,11 +141,6 @@ public function instanceSettingsForm(array $form, array &$form_state) {
       ),
       '#access' => $anonymous_user->hasPermission('post comments'),
     );
-    $element['comment']['subject'] = array(
-      '#type' => 'checkbox',
-      '#title' => t('Allow comment title'),
-      '#default_value' => $settings['subject'],
-    );
     $element['comment']['form_location'] = array(
       '#type' => 'checkbox',
       '#title' => t('Show reply form on the same page as comments'),
diff --git a/core/modules/comment/src/Tests/CommentAnonymousTest.php b/core/modules/comment/src/Tests/CommentAnonymousTest.php
index 03b88db..39794ca 100644
--- a/core/modules/comment/src/Tests/CommentAnonymousTest.php
+++ b/core/modules/comment/src/Tests/CommentAnonymousTest.php
@@ -69,7 +69,7 @@ function testAnonymous() {
     $edit = array(
       'name' => $this->admin_user->getUsername(),
       'mail' => $this->randomName() . '@example.com',
-      'subject' => $this->randomName(),
+      'subject[0][value]' => $this->randomName(),
       'comment_body[0][value]' => $this->randomName(),
     );
     $this->drupalPostForm('comment/reply/node/' . $this->node->id() . '/comment', $edit, t('Save'));
@@ -137,7 +137,7 @@ function testAnonymous() {
     // Attempt to view node-comment form while disallowed.
     $this->drupalGet('comment/reply/node/' . $this->node->id() . '/comment');
     $this->assertText('You are not authorized to post comments', 'Error attempting to post comment.');
-    $this->assertNoFieldByName('subject', '', 'Subject field not found.');
+    $this->assertNoFieldByName('subject[0][value]', '', 'Subject field not found.');
     $this->assertNoFieldByName('comment_body[0][value]', '', 'Comment field not found.');
 
     user_role_change_permissions(DRUPAL_ANONYMOUS_RID, array(
@@ -157,7 +157,7 @@ function testAnonymous() {
     ));
     $this->drupalGet('node/' . $this->node->id());
     $this->assertNoPattern('@<h2[^>]*>Comments</h2>@', 'Comments were not displayed.');
-    $this->assertFieldByName('subject', '', 'Subject field found.');
+    $this->assertFieldByName('subject[0][value]', '', 'Subject field found.');
     $this->assertFieldByName('comment_body[0][value]', '', 'Comment field found.');
 
     $this->drupalGet('comment/reply/node/' . $this->node->id() . '/comment/' . $anonymous_comment3->id());
diff --git a/core/modules/comment/src/Tests/CommentBookTest.php b/core/modules/comment/src/Tests/CommentBookTest.php
index 4d92e9d..de39c73 100644
--- a/core/modules/comment/src/Tests/CommentBookTest.php
+++ b/core/modules/comment/src/Tests/CommentBookTest.php
@@ -69,7 +69,7 @@ public function testBookCommentPrint() {
     $this->assertText($comment_subject, 'Comment subject found');
     $this->assertText($comment_body, 'Comment body found');
     $this->assertText(t('Add new comment'), 'Comment form found');
-    $this->assertField('subject', 'Comment form subject found');
+    $this->assertField('subject[0][value]', 'Comment form subject found');
 
     $this->drupalGet('book/export/html/' . $book_node->id());
 
@@ -78,7 +78,7 @@ public function testBookCommentPrint() {
     $this->assertText($comment_body, 'Comment body found');
 
     $this->assertNoText(t('Add new comment'), 'Comment form not found');
-    $this->assertNoField('subject', 'Comment form subject not found');
+    $this->assertNoField('subject[0][value]', 'Comment form subject not found');
   }
 
 }
diff --git a/core/modules/comment/src/Tests/CommentLanguageTest.php b/core/modules/comment/src/Tests/CommentLanguageTest.php
index aa3d5aa..d65e561 100644
--- a/core/modules/comment/src/Tests/CommentLanguageTest.php
+++ b/core/modules/comment/src/Tests/CommentLanguageTest.php
@@ -110,7 +110,7 @@ function testCommentLanguage() {
         $prefix = empty($prefixes[$langcode]) ? '' : $prefixes[$langcode] . '/';
         $comment_values[$node_langcode][$langcode] = $this->randomName();
         $edit = array(
-          'subject' => $this->randomName(),
+          'subject[0][value]' => $this->randomName(),
           'comment_body[0][value]' => $comment_values[$node_langcode][$langcode],
         );
         $this->drupalPostForm($prefix . 'node/' . $node->id(), $edit, t('Preview'));
diff --git a/core/modules/comment/src/Tests/CommentNonNodeTest.php b/core/modules/comment/src/Tests/CommentNonNodeTest.php
index f4f6fec..44d1ff4 100644
--- a/core/modules/comment/src/Tests/CommentNonNodeTest.php
+++ b/core/modules/comment/src/Tests/CommentNonNodeTest.php
@@ -102,18 +102,20 @@ function postComment(EntityInterface $entity, $comment, $subject = '', $contact
 
     $instance = FieldInstanceConfig::loadByName('entity_test', 'entity_test', 'comment');
     $preview_mode = $instance->getSetting('preview');
-    $subject_mode = $instance->getSetting('subject');
 
     // Must get the page before we test for fields.
     if ($entity !== NULL) {
       $this->drupalGet('comment/reply/entity_test/' . $entity->id() . '/comment');
     }
 
-    if ($subject_mode == TRUE) {
-      $edit['subject'] = $subject;
+    // Determine the visibility of subject form field.
+    if (entity_get_form_display('comment', 'comment', 'default')
+      ->getComponent('subject')) {
+      // Subject input allowed.
+      $edit['subject[0][value]'] = $subject;
     }
     else {
-      $this->assertNoFieldByName('subject', '', 'Subject field not found.');
+      $this->assertNoFieldByName('subject[0][value]', '', 'Subject field not found.');
     }
 
     if ($contact !== NULL && is_array($contact)) {
@@ -309,7 +311,7 @@ function testCommentFunctionality() {
     // Attempt to view test entity comment form while disallowed.
     $this->drupalGet('comment/reply/entity_test/' . $this->entity->id() . '/comment');
     $this->assertText('You are not authorized to post comments', 'Error attempting to post comment.');
-    $this->assertNoFieldByName('subject', '', 'Subject field not found.');
+    $this->assertNoFieldByName('subject[0][value]', '', 'Subject field not found.');
     $this->assertNoFieldByName('comment_body[0][value]', '', 'Comment field not found.');
 
     user_role_change_permissions(DRUPAL_ANONYMOUS_RID, array(
@@ -322,7 +324,7 @@ function testCommentFunctionality() {
     $this->assertPattern('@<h2[^>]*>Comments</h2>@', 'Comments were displayed.');
     $this->assertLink('Log in', 0, 'Link to log in was found.');
     $this->assertLink('register', 0, 'Link to register was found.');
-    $this->assertNoFieldByName('subject', '', 'Subject field not found.');
+    $this->assertNoFieldByName('subject[0][value]', '', 'Subject field not found.');
     $this->assertNoFieldByName('comment_body[0][value]', '', 'Comment field not found.');
 
     // Test the combination of anonymous users being able to post, but not view
@@ -336,7 +338,7 @@ function testCommentFunctionality() {
     ));
     $this->drupalGet('entity_test/' . $this->entity->id());
     $this->assertNoPattern('@<h2[^>]*>Comments</h2>@', 'Comments were not displayed.');
-    $this->assertFieldByName('subject', '', 'Subject field found.');
+    $this->assertFieldByName('subject[0][value]', '', 'Subject field found.');
     $this->assertFieldByName('comment_body[0][value]', '', 'Comment field found.');
 
     $this->drupalGet('comment/reply/entity_test/' . $this->entity->id() . '/comment/' . $comment1->id());
@@ -417,7 +419,7 @@ function testCommentFunctionality() {
     $this->assertNoField('edit-field-foobar-0-status-0');
 
     $this->drupalGet('comment/reply/entity_test/comment/' . $new_entity->id());
-    $this->assertNoFieldByName('subject', '', 'Subject field found.');
+    $this->assertNoFieldByName('subject[0][value]', '', 'Subject field found.');
     $this->assertNoFieldByName('comment_body[0][value]', '', 'Comment field found.');
   }
 
diff --git a/core/modules/comment/src/Tests/CommentPagerTest.php b/core/modules/comment/src/Tests/CommentPagerTest.php
index f712ce0..befed63 100644
--- a/core/modules/comment/src/Tests/CommentPagerTest.php
+++ b/core/modules/comment/src/Tests/CommentPagerTest.php
@@ -311,7 +311,6 @@ function testTwoPagers() {
     $comments = array();
     foreach (array('comment', 'comment_2') as $field_name) {
       $this->setCommentForm(TRUE, $field_name);
-      $this->setCommentSubject(TRUE, $field_name);
       $this->setCommentPreview(DRUPAL_OPTIONAL, $field_name);
       $this->setCommentSettings('default_mode', COMMENT_MODE_FLAT, 'Comment paging changed.', $field_name);
 
diff --git a/core/modules/comment/src/Tests/CommentPreviewTest.php b/core/modules/comment/src/Tests/CommentPreviewTest.php
index 1de62da..fbd29b5 100644
--- a/core/modules/comment/src/Tests/CommentPreviewTest.php
+++ b/core/modules/comment/src/Tests/CommentPreviewTest.php
@@ -54,17 +54,17 @@ function testCommentPreview() {
 
     // As the web user, fill in the comment form and preview the comment.
     $edit = array();
-    $edit['subject'] = $this->randomName(8);
+    $edit['subject[0][value]'] = $this->randomName(8);
     $edit['comment_body[0][value]'] = $this->randomName(16);
     $this->drupalPostForm('node/' . $this->node->id(), $edit, t('Preview'));
 
     // Check that the preview is displaying the title and body.
     $this->assertTitle(t('Preview comment | Drupal'), 'Page title is "Preview comment".');
-    $this->assertText($edit['subject'], 'Subject displayed.');
+    $this->assertText($edit['subject[0][value]'], 'Subject displayed.');
     $this->assertText($edit['comment_body[0][value]'], 'Comment displayed.');
 
     // Check that the title and body fields are displayed with the correct values.
-    $this->assertFieldByName('subject', $edit['subject'], 'Subject field displayed.');
+    $this->assertFieldByName('subject[0][value]', $edit['subject[0][value]'], 'Subject field displayed.');
     $this->assertFieldByName('comment_body[0][value]', $edit['comment_body[0][value]'], 'Comment field displayed.');
 
     // Check that the signature is displaying with the correct text format.
@@ -87,7 +87,7 @@ function testCommentEditPreviewSave() {
 
     $edit = array();
     $date = new DrupalDateTime('2008-03-02 17:23');
-    $edit['subject'] = $this->randomName(8);
+    $edit['subject[0][value]'] = $this->randomName(8);
     $edit['comment_body[0][value]'] = $this->randomName(16);
     $edit['name'] = $web_user->getUsername();
     $edit['date[date]'] = $date->format('Y-m-d');
@@ -96,18 +96,18 @@ function testCommentEditPreviewSave() {
     $expected_text_date = format_date($raw_date);
     $expected_form_date = $date->format('Y-m-d');
     $expected_form_time = $date->format('H:i:s');
-    $comment = $this->postComment($this->node, $edit['subject'], $edit['comment_body[0][value]'], TRUE);
+    $comment = $this->postComment($this->node, $edit['subject[0][value]'], $edit['comment_body[0][value]'], TRUE);
     $this->drupalPostForm('comment/' . $comment->id() . '/edit', $edit, t('Preview'));
 
     // Check that the preview is displaying the subject, comment, author and date correctly.
     $this->assertTitle(t('Preview comment | Drupal'), 'Page title is "Preview comment".');
-    $this->assertText($edit['subject'], 'Subject displayed.');
+    $this->assertText($edit['subject[0][value]'], 'Subject displayed.');
     $this->assertText($edit['comment_body[0][value]'], 'Comment displayed.');
     $this->assertText($edit['name'], 'Author displayed.');
     $this->assertText($expected_text_date, 'Date displayed.');
 
     // Check that the subject, comment, author and date fields are displayed with the correct values.
-    $this->assertFieldByName('subject', $edit['subject'], 'Subject field displayed.');
+    $this->assertFieldByName('subject[0][value]', $edit['subject[0][value]'], 'Subject field displayed.');
     $this->assertFieldByName('comment_body[0][value]', $edit['comment_body[0][value]'], 'Comment field displayed.');
     $this->assertFieldByName('name', $edit['name'], 'Author field displayed.');
     $this->assertFieldByName('date[date]', $edit['date[date]'], 'Date field displayed.');
@@ -119,7 +119,7 @@ function testCommentEditPreviewSave() {
 
     // Check that the comment fields are correct after loading the saved comment.
     $this->drupalGet('comment/' . $comment->id() . '/edit');
-    $this->assertFieldByName('subject', $edit['subject'], 'Subject field displayed.');
+    $this->assertFieldByName('subject[0][value]', $edit['subject[0][value]'], 'Subject field displayed.');
     $this->assertFieldByName('comment_body[0][value]', $edit['comment_body[0][value]'], 'Comment field displayed.');
     $this->assertFieldByName('name', $edit['name'], 'Author field displayed.');
     $this->assertFieldByName('date[date]', $expected_form_date, 'Date field displayed.');
@@ -127,7 +127,7 @@ function testCommentEditPreviewSave() {
 
     // Submit the form using the displayed values.
     $displayed = array();
-    $displayed['subject'] = (string) current($this->xpath("//input[@id='edit-subject']/@value"));
+    $displayed['subject[0][value]'] = (string) current($this->xpath("//input[@id='edit-subject-0-value']/@value"));
     $displayed['comment_body[0][value]'] = (string) current($this->xpath("//textarea[@id='edit-comment-body-0-value']"));
     $displayed['name'] = (string) current($this->xpath("//input[@id='edit-name']/@value"));
     $displayed['date[date]'] = (string) current($this->xpath("//input[@id='edit-date-date']/@value"));
@@ -136,7 +136,7 @@ function testCommentEditPreviewSave() {
 
     // Check that the saved comment is still correct.
     $comment_loaded = comment_load($comment->id(), TRUE);
-    $this->assertEqual($comment_loaded->getSubject(), $edit['subject'], 'Subject loaded.');
+    $this->assertEqual($comment_loaded->getSubject(), $edit['subject[0][value]'], 'Subject loaded.');
     $this->assertEqual($comment_loaded->comment_body->value, $edit['comment_body[0][value]'], 'Comment body loaded.');
     $this->assertEqual($comment_loaded->getAuthorName(), $edit['name'], 'Name loaded.');
     $this->assertEqual($comment_loaded->getCreatedTime(), $raw_date, 'Date loaded.');
diff --git a/core/modules/comment/src/Tests/CommentTestBase.php b/core/modules/comment/src/Tests/CommentTestBase.php
index a93110b..f365e83 100644
--- a/core/modules/comment/src/Tests/CommentTestBase.php
+++ b/core/modules/comment/src/Tests/CommentTestBase.php
@@ -113,18 +113,20 @@ public function postComment($entity, $comment, $subject = '', $contact = NULL, $
       $instance = FieldInstanceConfig::loadByName('node', 'article', $field_name);
     }
     $preview_mode = $instance->settings['preview'];
-    $subject_mode = $instance->settings['subject'];
 
     // Must get the page before we test for fields.
     if ($entity !== NULL) {
       $this->drupalGet('comment/reply/node/' . $entity->id() . '/' . $field_name);
     }
 
-    if ($subject_mode == TRUE) {
-      $edit['subject'] = $subject;
+    // Determine the visibility of subject form field.
+    if (entity_get_form_display('comment', 'comment', 'default')
+      ->getComponent('subject')) {
+      // Subject input allowed.
+      $edit['subject[0][value]'] = $subject;
     }
     else {
-      $this->assertNoFieldByName('subject', '', 'Subject field not found.');
+      $this->assertNoFieldByName('subject[0][value]', '', 'Subject field not found.');
     }
 
     if ($contact !== NULL && is_array($contact)) {
@@ -209,12 +211,20 @@ function deleteComment(CommentInterface $comment) {
    *
    * @param bool $enabled
    *   Boolean specifying whether the subject field should be enabled.
-   * @param string $field_name
-   *   (optional) Field name through which the comment should be posted.
-   *   Defaults to 'comment'.
    */
-  public function setCommentSubject($enabled, $field_name = 'comment') {
-    $this->setCommentSettings('subject', ($enabled ? '1' : '0'), 'Comment subject ' . ($enabled ? 'enabled' : 'disabled') . '.', $field_name);
+  public function setCommentSubject($enabled) {
+    $form_display = entity_get_form_display('comment', 'comment', 'default');
+    if ($enabled) {
+      $form_display->setComponent('subject', array(
+        'type' => 'string',
+      ));
+    }
+    else {
+      $form_display->removeComponent('subject');
+    }
+    $form_display->save();
+    // Display status message.
+    $this->pass('Comment subject ' . ($enabled ? 'enabled' : 'disabled') . '.');
   }
 
   /**
diff --git a/core/modules/comment/src/Tests/CommentTranslationUITest.php b/core/modules/comment/src/Tests/CommentTranslationUITest.php
index 7314c30..e4d2915 100644
--- a/core/modules/comment/src/Tests/CommentTranslationUITest.php
+++ b/core/modules/comment/src/Tests/CommentTranslationUITest.php
@@ -112,7 +112,7 @@ protected function createEntity($values, $langcode, $comment_type = 'comment_art
   protected function getNewEntityValues($langcode) {
     // Comment subject is not translatable hence we use a fixed value.
     return array(
-      'subject' => $this->subject,
+      'subject' => array(array('value' => $this->subject)),
       'comment_body' => array(array('value' => $this->randomName(16))),
     ) + parent::getNewEntityValues($langcode);
   }
diff --git a/core/modules/forum/src/Tests/ForumTest.php b/core/modules/forum/src/Tests/ForumTest.php
index 6217835..df243ce 100644
--- a/core/modules/forum/src/Tests/ForumTest.php
+++ b/core/modules/forum/src/Tests/ForumTest.php
@@ -456,7 +456,7 @@ function testForumWithNewPost() {
     $this->drupalLogin($this->post_comment_user);
     // Post a reply to the topic.
     $edit = array();
-    $edit['subject'] = $this->randomName();
+    $edit['subject[0][value]'] = $this->randomName();
     $edit['comment_body[0][value]'] = $this->randomName();
     $this->drupalPostForm('node/' . $node->id(), $edit, t('Save'));
     $this->assertResponse(200);
diff --git a/core/modules/search/src/Tests/SearchCommentCountToggleTest.php b/core/modules/search/src/Tests/SearchCommentCountToggleTest.php
index 64c1171..588c640 100644
--- a/core/modules/search/src/Tests/SearchCommentCountToggleTest.php
+++ b/core/modules/search/src/Tests/SearchCommentCountToggleTest.php
@@ -58,7 +58,7 @@ function setUp() {
 
     // Create a comment array
     $edit_comment = array();
-    $edit_comment['subject'] = $this->randomName();
+    $edit_comment['subject[0][value]'] = $this->randomName();
     $edit_comment['comment_body[0][value]'] = $this->randomName();
 
     // Post comment to the test node with comment
diff --git a/core/modules/search/src/Tests/SearchCommentTest.php b/core/modules/search/src/Tests/SearchCommentTest.php
index c825d2a..0c564d6 100644
--- a/core/modules/search/src/Tests/SearchCommentTest.php
+++ b/core/modules/search/src/Tests/SearchCommentTest.php
@@ -96,7 +96,7 @@ function testSearchResultsComment() {
     $node = $this->drupalCreateNode(array('type' => 'article'));
     // Post a comment using 'Full HTML' text format.
     $edit_comment = array();
-    $edit_comment['subject'] = 'Test comment subject';
+    $edit_comment['subject[0][value]'] = 'Test comment subject';
     $edit_comment['comment_body[0][value]'] = '<h1>' . $comment_body . '</h1>';
     $full_html_format_id = 'full_html';
     $edit_comment['comment_body[0][format]'] = $full_html_format_id;
@@ -108,12 +108,12 @@ function testSearchResultsComment() {
 
     // Search for the comment subject.
     $edit = array(
-      'keys' => "'" . $edit_comment['subject'] . "'",
+      'keys' => "'" . $edit_comment['subject[0][value]'] . "'",
     );
     $this->drupalPostForm('search/node', $edit, t('Search'));
     $node2 = node_load($node->id(), TRUE);
     $this->assertText($node2->label(), 'Node found in search results.');
-    $this->assertText($edit_comment['subject'], 'Comment subject found in search results.');
+    $this->assertText($edit_comment['subject[0][value]'], 'Comment subject found in search results.');
 
     // Search for the comment body.
     $edit = array(
@@ -159,7 +159,7 @@ function testSearchResultsCommentAccess() {
 
     // Post a comment using 'Full HTML' text format.
     $edit_comment = array();
-    $edit_comment['subject'] = $this->comment_subject;
+    $edit_comment['subject[0][value]'] = $this->comment_subject;
     $edit_comment['comment_body[0][value]'] = '<h1>' . $comment_body . '</h1>';
     $this->drupalPostForm('comment/reply/node/' . $this->node->id() . '/comment', $edit_comment, t('Save'));
 
diff --git a/core/modules/search/src/Tests/SearchRankingTest.php b/core/modules/search/src/Tests/SearchRankingTest.php
index 48410d6..96e990f 100644
--- a/core/modules/search/src/Tests/SearchRankingTest.php
+++ b/core/modules/search/src/Tests/SearchRankingTest.php
@@ -87,7 +87,7 @@ public function testRankings() {
 
     // Add a comment to one of the nodes.
     $edit = array();
-    $edit['subject'] = 'my comment title';
+    $edit['subject[0][value]'] = 'my comment title';
     $edit['comment_body[0][value]'] = 'some random comment';
     $this->drupalGet('comment/reply/node/' . $nodes['comments'][1]->id() . '/comment');
     $this->drupalPostForm(NULL, $edit, t('Preview'));
diff --git a/core/modules/tracker/src/Tests/TrackerTest.php b/core/modules/tracker/src/Tests/TrackerTest.php
index f4e9912..bbd6f73 100644
--- a/core/modules/tracker/src/Tests/TrackerTest.php
+++ b/core/modules/tracker/src/Tests/TrackerTest.php
@@ -108,7 +108,7 @@ function testTrackerUser() {
       'status' => 1,
     ));
     $comment = array(
-      'subject' => $this->randomName(),
+      'subject[0][value]' => $this->randomName(),
       'comment_body[0][value]' => $this->randomName(20),
     );
     $this->drupalPostForm('comment/reply/node/' . $other_published_my_comment->id() . '/comment', $comment, t('Save'));
@@ -186,7 +186,7 @@ function testTrackerNewComments() {
 
     // Add a comment to the page.
     $comment = array(
-      'subject' => $this->randomName(),
+      'subject[0][value]' => $this->randomName(),
       'comment_body[0][value]' => $this->randomName(20),
     );
     $this->drupalPostForm('comment/reply/node/' . $node->id() . '/comment', $comment, t('Save'));
@@ -207,7 +207,7 @@ function testTrackerNewComments() {
 
     // Add another comment as other_user.
     $comment = array(
-      'subject' => $this->randomName(),
+      'subject[0][value]' => $this->randomName(),
       'comment_body[0][value]' => $this->randomName(20),
     );
     // If the comment is posted in the same second as the last one then Drupal
@@ -239,7 +239,7 @@ function testTrackerOrderingNewComments() {
 
     // Add a comment to the first page.
     $comment = array(
-      'subject' => $this->randomName(),
+      'subject[0][value]' => $this->randomName(),
       'comment_body[0][value]' => $this->randomName(20),
     );
     $this->drupalPostForm('comment/reply/node/' . $node_one->id() . '/comment', $comment, t('Save'));
@@ -250,7 +250,7 @@ function testTrackerOrderingNewComments() {
 
     // Add a comment to the second page.
     $comment = array(
-      'subject' => $this->randomName(),
+      'subject[0][value]' => $this->randomName(),
       'comment_body[0][value]' => $this->randomName(20),
     );
     $this->drupalPostForm('comment/reply/node/' . $node_two->id() . '/comment', $comment, t('Save'));
@@ -270,7 +270,7 @@ function testTrackerOrderingNewComments() {
 
     // Add a comment to the second page.
     $comment = array(
-      'subject' => $this->randomName(),
+      'subject[0][value]' => $this->randomName(),
       'comment_body[0][value]' => $this->randomName(20),
     );
     $this->drupalPostForm('comment/reply/node/' . $node_one->id() . '/comment', $comment, t('Save'));
@@ -305,7 +305,7 @@ function testTrackerCronIndexing() {
     // Add a comment to the last node as other user.
     $this->drupalLogin($this->other_user);
     $comment = array(
-      'subject' => $this->randomName(),
+      'subject[0][value]' => $this->randomName(),
       'comment_body[0][value]' => $this->randomName(20),
     );
     $this->drupalPostForm('comment/reply/node/' . $nodes[3]->id() . '/comment', $comment, t('Save'));
diff --git a/core/modules/user/src/Tests/UserCancelTest.php b/core/modules/user/src/Tests/UserCancelTest.php
index 66c66af..03c1cd9 100644
--- a/core/modules/user/src/Tests/UserCancelTest.php
+++ b/core/modules/user/src/Tests/UserCancelTest.php
@@ -319,13 +319,13 @@ function testUserDelete() {
 
     // Create comment.
     $edit = array();
-    $edit['subject'] = $this->randomName(8);
+    $edit['subject[0][value]'] = $this->randomName(8);
     $edit['comment_body[0][value]'] = $this->randomName(16);
 
     $this->drupalPostForm('comment/reply/node/' . $node->id() . '/comment', $edit, t('Preview'));
     $this->drupalPostForm(NULL, array(), t('Save'));
     $this->assertText(t('Your comment has been posted.'));
-    $comments = entity_load_multiple_by_properties('comment', array('subject' => $edit['subject']));
+    $comments = entity_load_multiple_by_properties('comment', array('subject' => $edit['subject[0][value]']));
     $comment = reset($comments);
     $this->assertTrue($comment->id(), 'Comment found.');
 
diff --git a/core/modules/user/src/Tests/UserSignatureTest.php b/core/modules/user/src/Tests/UserSignatureTest.php
index ce6c5ff..75dfdc7 100644
--- a/core/modules/user/src/Tests/UserSignatureTest.php
+++ b/core/modules/user/src/Tests/UserSignatureTest.php
@@ -112,7 +112,7 @@ function testUserSignature() {
 
     // Create a comment.
     $edit = array();
-    $edit['subject'] = $this->randomName(8);
+    $edit['subject[0][value]'] = $this->randomName(8);
     $edit['comment_body[0][value]'] = $this->randomName(16);
     $this->drupalPostForm('comment/reply/node/' . $node->id() .'/comment', $edit, t('Preview'));
     $this->drupalPostForm(NULL, array(), t('Save'));
diff --git a/core/profiles/standard/src/Tests/StandardTest.php b/core/profiles/standard/src/Tests/StandardTest.php
index 3a1eead..7b483c2 100644
--- a/core/profiles/standard/src/Tests/StandardTest.php
+++ b/core/profiles/standard/src/Tests/StandardTest.php
@@ -85,7 +85,7 @@ function testStandard() {
     $this->drupalLogin($admin);
     $this->drupalGet('node/1');
     $this->drupalPostForm(NULL, array(
-      'subject' => 'Barfoo',
+      'subject[0][value]' => 'Barfoo',
       'comment_body[0][value]' => 'Then she picked out two somebodies, Sally and me',
     ), t('Save'));
     // Fetch the feed.