diff --git a/core/modules/comment/comment.install b/core/modules/comment/comment.install
index 04e1291..3462a31 100644
--- a/core/modules/comment/comment.install
+++ b/core/modules/comment/comment.install
@@ -29,7 +29,7 @@ function comment_uninstall() {
     variable_del('comment_subject_field_' . $node_type);
   }
 
-  // Remove states.
+  // Remove state setting.
   Drupal::state()->delete('comment.node_comment_statistics_scale');
 }
 
diff --git a/core/modules/comment/comment.module b/core/modules/comment/comment.module
index 808ac54..58bf81c 100644
--- a/core/modules/comment/comment.module
+++ b/core/modules/comment/comment.module
@@ -9,14 +9,12 @@
  * book page, etc.
  */
 
-use Drupal\node\NodeTypeInterface;
+use Drupal\Core\Entity\EntityInterface;
+use Drupal\comment\CommentInterface;
 use Drupal\entity\Entity\EntityDisplay;
 use Drupal\file\Entity\File;
-use Drupal\Core\Entity\EntityInterface;
 use Drupal\node\NodeInterface;
-use Symfony\Component\HttpFoundation\Request;
-use Symfony\Component\HttpKernel\Exception\NotFoundHttpException;
-use Symfony\Component\HttpKernel\HttpKernelInterface;
+use Drupal\node\NodeTypeInterface;
 
 /**
  * Comment is awaiting approval.
@@ -78,8 +76,6 @@
  */
 const COMMENT_NODE_OPEN = 2;
 
-use Drupal\comment\Entity\Comment;
-
 /**
  * Implements hook_help().
  */
@@ -118,7 +114,7 @@ function comment_entity_bundle_info() {
 /**
  * Entity URI callback.
  */
-function comment_uri(Comment $comment) {
+function comment_uri(CommentInterface $comment) {
   return array(
     'path' => 'comment/' . $comment->id(),
     'options' => array('fragment' => 'comment-' . $comment->id()),
@@ -376,10 +372,10 @@ function comment_permission() {
 /**
  * Finds the most recent comments that are available to the current user.
  *
- * @param integer $number
+ * @param int $number
  *   (optional) The maximum number of comments to find. Defaults to 10.
  *
- * @return
+ * @return array
  *   An array of comment objects or an empty array if there are no recent
  *   comments visible to the current user.
  */
@@ -409,15 +405,15 @@ function comment_get_recent($number = 10) {
 /**
  * Calculates the page number for the first new comment.
  *
- * @param $num_comments
+ * @param int $num_comments
  *   Number of comments.
- * @param $new_replies
+ * @param int $new_replies
  *   Number of new replies.
  * @param \Drupal\Core\Entity\EntityInterface $node
  *   The first new comment node.
  *
- * @return
- *   "page=X" if the page number is greater than zero; empty string otherwise.
+ * @return array|NULL
+ *   Array "page=X" if the page number is greater than zero; NULL otherwise.
  */
 function comment_new_page_count($num_comments, $new_replies, EntityInterface $node) {
   $mode = variable_get('comment_default_mode_' . $node->getType(), COMMENT_MODE_THREADED);
@@ -633,7 +629,7 @@ function comment_node_view_alter(&$build, EntityInterface $node, EntityDisplay $
  * @param \Drupal\Core\Entity\EntityInterface $node
  *   The node entity for which to build the comment-related elements.
  *
- * @return
+ * @return array
  *   A renderable array representing the comment-related page elements for the
  *   node.
  */
@@ -695,12 +691,12 @@ function comment_add(EntityInterface $node, $pid = NULL) {
  *
  * @param \Drupal\Core\Entity\EntityInterface $node
  *   The node whose comment(s) needs rendering.
- * @param $mode
+ * @param int $mode
  *   The comment display mode; COMMENT_MODE_FLAT or COMMENT_MODE_THREADED.
- * @param $comments_per_page
+ * @param int $comments_per_page
  *   The amount of comments to display per page.
  *
- * @return
+ * @return array
  *   An array of the IDs of the comment to be displayed.
  *
  * To display threaded comments in the correct order we keep a 'thread' field
@@ -813,7 +809,7 @@ function comment_prepare_thread(&$comments) {
   // A counter that helps track how indented we are.
   $divs = 0;
 
-  foreach ($comments as $key => $comment) {
+  foreach ($comments as $key => &$comment) {
     // The $divs element instructs #prefix whether to add an indent div or
     // close existing divs (a negative value).
     $comment->depth = count(explode('.', $comment->thread->value)) - 1;
@@ -827,7 +823,6 @@ function comment_prepare_thread(&$comments) {
         $divs--;
       }
     }
-    $comments[$key] = $comment;
   }
 
   // The final comment must close up some hanging divs
@@ -837,33 +832,33 @@ function comment_prepare_thread(&$comments) {
 /**
  * Generates an array for rendering a comment.
  *
- * @param Drupal\comment\Comment $comment
+ * @param \Drupal\comment\CommentInterface $comment
  *   The comment object.
  * @param $view_mode
- *   View mode, e.g. 'full', 'teaser'...
+ *   (optional) View mode, e.g. 'full', 'teaser'... Defaults to 'full'.
  * @param $langcode
  *   (optional) A language code to use for rendering. Defaults to the global
  *   content language of the current request.
  *
- * @return
+ * @return array
  *   An array as expected by drupal_render().
  */
-function comment_view(Comment $comment, $view_mode = 'full', $langcode = NULL) {
+function comment_view(CommentInterface $comment, $view_mode = 'full', $langcode = NULL) {
   return entity_view($comment, $view_mode, $langcode);
 }
 
 /**
  * Adds reply, edit, delete, etc. links, depending on user permissions.
  *
- * @param Drupal\comment\Comment $comment
+ * @param \Drupal\comment\CommentInterface $comment
  *   The comment object.
  * @param \Drupal\Core\Entity\EntityInterface $node
  *   The node the comment is attached to.
  *
- * @return
+ * @return array
  *   A structured array of links.
  */
-function comment_links(Comment $comment, EntityInterface $node) {
+function comment_links(CommentInterface $comment, EntityInterface $node) {
   $links = array();
   if ($node->comment->value == COMMENT_NODE_OPEN) {
     if ($comment->access('delete')) {
@@ -925,10 +920,11 @@ function comment_links(Comment $comment, EntityInterface $node) {
  * @param $view_mode
  *   View mode, e.g. 'full', 'teaser'...
  * @param $langcode
- *   A string indicating the language field values are to be shown in. If no
- *   language is provided the current content language is used.
+ *   (optional) A string indicating the language field values are to be shown
+ *   in. If no language is provided the current content language is used.
+ *   Defaults to NULL.
  *
- * @return
+ * @return array
  *   An array in the format expected by drupal_render().
  *
  * @see drupal_render()
@@ -1294,7 +1290,7 @@ function comment_load_multiple(array $cids = NULL, $reset = FALSE) {
  * @param bool $reset
  *   (optional) Whether to reset the internal static entity cache.
  *
- * @return
+ * @return \Drupal\comment\CommentInterface
  *   The comment object.
  */
 function comment_load($cid, $reset = FALSE) {
@@ -1304,13 +1300,12 @@ function comment_load($cid, $reset = FALSE) {
 /**
  * Gets the number of new comments for the current user and the specified node.
  *
- * @param $nid
+ * @param int $nid
  *   Node ID to count comments for.
- * @param $timestamp
- *   Time to count from (defaults to time of last user access
- *   to node).
+ * @param int $timestamp
+ *   Time to count from (defaults to time of last user access to node).
  *
- * @return
+ * @return int|FALSE
  *   The number of new comments or FALSE if the user is not logged in.
  */
 function comment_num_new($nid, $timestamp = 0) {
@@ -1342,12 +1337,12 @@ function comment_num_new($nid, $timestamp = 0) {
  * Count the number of comments which appear before the comment we want to
  * display, taking into account display settings and threading.
  *
- * @param $cid
+ * @param int $cid
  *   The comment ID.
- * @param $node_type
+ * @param string $node_type
  *   The node type of the comment's parent.
  *
- * @return
+ * @return int
  *   The display ordinal for the comment.
  *
  * @see comment_get_display_page()
@@ -1386,12 +1381,12 @@ function comment_get_display_ordinal($cid, $node_type) {
  * Finds the correct page number for a comment taking into account display
  * and paging settings.
  *
- * @param $cid
+ * @param int $cid
  *   The comment ID.
- * @param $node_type
+ * @param string $node_type
  *   The node type the comment is attached to.
  *
- * @return
+ * @return int
  *   The page number.
  */
 function comment_get_display_page($cid, $node_type) {
@@ -1403,9 +1398,13 @@ function comment_get_display_page($cid, $node_type) {
 /**
  * Generates a comment preview.
  *
- * @param Drupal\comment\Comment $comment
+ * @param \Drupal\comment\CommentInterface $comment
+ *   The comment entity to preview.
+ *
+ * @return array
+ *   An array as expected by drupal_render().
  */
-function comment_preview(Comment $comment) {
+function comment_preview(CommentInterface $comment) {
   global $user;
   $preview_build = array();
 
@@ -1467,10 +1466,13 @@ function comment_preprocess_block(&$variables) {
  * This helper handles anonymous authors in addition to registered comment
  * authors.
  *
- * @return \Drupal\user\Entity\User
+ * @param \Drupal\comment\CommentInterface $comment
+ *   The comment to which the author replied.
+ *
+ * @return \Drupal\user\UserInterface
  *   A user account, for use with theme_username() or the user_picture template.
  */
-function comment_prepare_author(Comment $comment) {
+function comment_prepare_author(CommentInterface $comment) {
   // The account has been pre-loaded by CommentRenderController::buildContent().
   $account = $comment->uid->entity;
   if (empty($account->uid->value)) {
diff --git a/core/modules/comment/comment.views.inc b/core/modules/comment/comment.views.inc
index d8887ff..861289c 100644
--- a/core/modules/comment/comment.views.inc
+++ b/core/modules/comment/comment.views.inc
@@ -98,7 +98,7 @@ function comment_views_data() {
     'help' => t('Hostname of user that posted the comment.'),
     'field' => array(
       'id' => 'standard',
-     ),
+    ),
     'filter' => array(
       'id' => 'string',
     ),
@@ -115,7 +115,7 @@ function comment_views_data() {
     'help' => t('E-mail of user that posted the comment. Will be empty if the author is a registered user.'),
     'field' => array(
       'id' => 'standard',
-     ),
+    ),
     'filter' => array(
       'id' => 'string',
     ),
diff --git a/core/modules/comment/lib/Drupal/comment/CommentInterface.php b/core/modules/comment/lib/Drupal/comment/CommentInterface.php
index 456b957..fb9c043 100644
--- a/core/modules/comment/lib/Drupal/comment/CommentInterface.php
+++ b/core/modules/comment/lib/Drupal/comment/CommentInterface.php
@@ -24,4 +24,5 @@
    *   UrlGenerator::generateFromPath().
    */
   public function permalink();
+
 }
diff --git a/core/modules/comment/lib/Drupal/comment/CommentStorageController.php b/core/modules/comment/lib/Drupal/comment/CommentStorageController.php
index 3dc7f2c..b1dece7 100644
--- a/core/modules/comment/lib/Drupal/comment/CommentStorageController.php
+++ b/core/modules/comment/lib/Drupal/comment/CommentStorageController.php
@@ -9,8 +9,6 @@
 
 use Drupal\Core\Entity\EntityInterface;
 use Drupal\Core\Entity\DatabaseStorageControllerNG;
-use Drupal\Component\Uuid\Uuid;
-use LogicException;
 
 /**
  * Defines the controller class for comments.
@@ -44,10 +42,9 @@ protected function buildQuery($ids, $revision_id = FALSE) {
    */
   protected function attachLoad(&$records, $load_revision = FALSE) {
     // Prepare standard comment fields.
-    foreach ($records as $key => $record) {
+    foreach ($records as $key => &$record) {
       $record->name = $record->uid ? $record->registered_name : $record->name;
       $record->node_type = 'comment_node_' . $record->node_type;
-      $records[$key] = $record;
     }
     parent::attachLoad($records, $load_revision);
   }
@@ -127,4 +124,5 @@ public function getChildCids(array $comments) {
       ->execute()
       ->fetchCol();
   }
+
 }
diff --git a/core/modules/comment/lib/Drupal/comment/Controller/CommentController.php b/core/modules/comment/lib/Drupal/comment/Controller/CommentController.php
index 48a23cd..dc2c35d 100644
--- a/core/modules/comment/lib/Drupal/comment/Controller/CommentController.php
+++ b/core/modules/comment/lib/Drupal/comment/Controller/CommentController.php
@@ -8,11 +8,10 @@
 namespace Drupal\comment\Controller;
 
 use Drupal\comment\CommentInterface;
-use Drupal\comment\Entity\Comment;
+use Drupal\node\NodeInterface;
 use Drupal\Core\Access\CsrfTokenGenerator;
 use Drupal\Core\Controller\ControllerBase;
 use Drupal\Core\DependencyInjection\ContainerInjectionInterface;
-use Drupal\Node\NodeInterface;
 use Drupal\Core\Session\AccountInterface;
 use Symfony\Component\DependencyInjection\ContainerInterface;
 use Symfony\Component\HttpFoundation\JsonResponse;
@@ -242,7 +241,7 @@ public function getReplyForm(Request $request, NodeInterface $node, $pid = NULL)
    * @param \Symfony\Component\HttpFoundation\Request $request
    *   The request of the page.
    *
-   * @return Symfony\Component\HttpFoundation\JsonResponse
+   * @return \Symfony\Component\HttpFoundation\JsonResponse
    *   The JSON response.
    */
   public function renderNewCommentsNodeLinks(Request $request) {
diff --git a/core/modules/comment/lib/Drupal/comment/Entity/Comment.php b/core/modules/comment/lib/Drupal/comment/Entity/Comment.php
index d46fb3d..e437fd57 100644
--- a/core/modules/comment/lib/Drupal/comment/Entity/Comment.php
+++ b/core/modules/comment/lib/Drupal/comment/Entity/Comment.php
@@ -55,7 +55,7 @@ class Comment extends EntityNG implements CommentInterface {
   /**
    * The comment ID.
    *
-   * @todo Rename to 'id'.
+   * @todo Rename to 'id'. https://drupal.org/node/2031935
    *
    * @var \Drupal\Core\Entity\Field\FieldInterface
    */
@@ -69,9 +69,9 @@ class Comment extends EntityNG implements CommentInterface {
   public $uuid;
 
   /**
-   * The parent comment ID if this is a reply to a comment.
+   * The parent comment ID if this is a reply to another comment.
    *
-   * @todo: Rename to 'parent_id'.
+   * @todo: Rename to 'parent_id'. https://drupal.org/node/2031931
    *
    * @var \Drupal\Core\Entity\Field\FieldInterface
    */
diff --git a/core/modules/comment/lib/Drupal/comment/Form/DeleteForm.php b/core/modules/comment/lib/Drupal/comment/Form/DeleteForm.php
index fd86ddf..df6f464 100644
--- a/core/modules/comment/lib/Drupal/comment/Form/DeleteForm.php
+++ b/core/modules/comment/lib/Drupal/comment/Form/DeleteForm.php
@@ -9,7 +9,6 @@
 
 use Drupal\Core\Cache\Cache;
 use Drupal\Core\Entity\EntityNGConfirmFormBase;
-use Symfony\Component\HttpFoundation\Request;
 
 /**
  * Provides the comment delete confirmation form.