diff --git a/core/modules/action/tests/Drupal/action/Tests/Menu/ActionLocalTasksTest.php b/core/modules/action/tests/Drupal/action/Tests/Menu/ActionLocalTasksTest.php
index 891db5b..729d314 100644
--- a/core/modules/action/tests/Drupal/action/Tests/Menu/ActionLocalTasksTest.php
+++ b/core/modules/action/tests/Drupal/action/Tests/Menu/ActionLocalTasksTest.php
@@ -26,7 +26,7 @@ public static function getInfo() {
   }
 
   public function setUp() {
-    $this->moduleList = array('action' => 'core/modules/action/action.info.yml');
+    $this->moduleList = array('action' => 'core/modules/action/action.module');
     parent::setUp();
   }
 
diff --git a/core/modules/aggregator/tests/Drupal/aggregator/Tests/Menu/AggregatorLocalTasksTest.php b/core/modules/aggregator/tests/Drupal/aggregator/Tests/Menu/AggregatorLocalTasksTest.php
index 67bedd8..5119603 100644
--- a/core/modules/aggregator/tests/Drupal/aggregator/Tests/Menu/AggregatorLocalTasksTest.php
+++ b/core/modules/aggregator/tests/Drupal/aggregator/Tests/Menu/AggregatorLocalTasksTest.php
@@ -26,7 +26,7 @@ public static function getInfo() {
   }
 
   public function setUp() {
-    $this->moduleList = array('aggregator' => 'core/modules/aggregator/aggregator.info.yml');
+    $this->moduleList = array('aggregator' => 'core/modules/aggregator/aggregator.module');
     parent::setUp();
   }
 
diff --git a/core/modules/block/block.module b/core/modules/block/block.module
index 4d96430..e27af49 100644
--- a/core/modules/block/block.module
+++ b/core/modules/block/block.module
@@ -5,16 +5,12 @@
  * Controls the visual building blocks a page is constructed with.
  */
 
+use Drupal\block\BlockInterface;
 use Drupal\Component\Plugin\Exception\PluginException;
 use Drupal\Component\Utility\NestedArray;
 use Symfony\Cmf\Component\Routing\RouteObjectInterface;
 
 /**
- * Denotes that a block is not enabled in any region and should not be shown.
- */
-const BLOCK_REGION_NONE = -1;
-
-/**
  * Shows this block on every page except the listed pages.
  */
 const BLOCK_VISIBILITY_NOTLISTED = 0;
@@ -308,15 +304,15 @@ function _block_rehash($theme = NULL) {
     $region = $block->get('region');
     $status = $block->status();
     // Disable blocks in invalid regions.
-    if (!empty($region) && $region != BLOCK_REGION_NONE && !isset($regions[$region]) && $status) {
+    if (!empty($region) && $region != BlockInterface::BLOCK_REGION_NONE && !isset($regions[$region]) && $status) {
       drupal_set_message(t('The block %info was assigned to the invalid region %region and has been disabled.', array('%info' => $block_id, '%region' => $region)), 'warning');
-      // Disabled modules are moved into the BLOCK_REGION_NONE later so no
-      // need to move the block to another region.
+      // Disabled modules are moved into the BlockInterface::BLOCK_REGION_NONE
+      // later so no need to move the block to another region.
       $block->disable()->save();
     }
     // Set region to none if not enabled.
     if (!$status) {
-      $block->set('region', BLOCK_REGION_NONE);
+      $block->set('region', BlockInterface::BLOCK_REGION_NONE);
       $block->save();
     }
   }
diff --git a/core/modules/block/custom_block/tests/Drupal/custom_blocks/Tests/Menu/CustomBlockLocalTasksTest.php b/core/modules/block/custom_block/tests/Drupal/custom_blocks/Tests/Menu/CustomBlockLocalTasksTest.php
index 96866fd..39ddc54 100644
--- a/core/modules/block/custom_block/tests/Drupal/custom_blocks/Tests/Menu/CustomBlockLocalTasksTest.php
+++ b/core/modules/block/custom_block/tests/Drupal/custom_blocks/Tests/Menu/CustomBlockLocalTasksTest.php
@@ -27,8 +27,8 @@ public static function getInfo() {
 
   public function setUp() {
     $this->moduleList = array(
-      'block' => 'core/modules/block/block.info.yml',
-      'custom_block' => 'core/modules/block/custom_block/custom_block.info.yml',
+      'block' => 'core/modules/block/block.module',
+      'custom_block' => 'core/modules/block/custom_block/custom_block.module',
     );
     parent::setUp();
   }
diff --git a/core/modules/block/lib/Drupal/block/BlockFormController.php b/core/modules/block/lib/Drupal/block/BlockFormController.php
index 92d3696..e2692a4 100644
--- a/core/modules/block/lib/Drupal/block/BlockFormController.php
+++ b/core/modules/block/lib/Drupal/block/BlockFormController.php
@@ -259,7 +259,7 @@ public function form(array $form, array &$form_state) {
       '#title' => $this->t('Region'),
       '#description' => $this->t('Select the region where this block should be displayed.'),
       '#default_value' => $entity->get('region'),
-      '#empty_value' => BLOCK_REGION_NONE,
+      '#empty_value' => BlockInterface::BLOCK_REGION_NONE,
       '#options' => system_region_list($theme, REGIONS_VISIBLE),
       '#prefix' => '<div id="edit-block-region-wrapper">',
       '#suffix' => '</div>',
diff --git a/core/modules/block/lib/Drupal/block/BlockInterface.php b/core/modules/block/lib/Drupal/block/BlockInterface.php
index 0ffbcfc..de0d9de 100644
--- a/core/modules/block/lib/Drupal/block/BlockInterface.php
+++ b/core/modules/block/lib/Drupal/block/BlockInterface.php
@@ -20,6 +20,11 @@
   const BLOCK_LABEL_VISIBLE = 'visible';
 
   /**
+   * Denotes that a block is not enabled in any region and should not be shown.
+   */
+  const BLOCK_REGION_NONE = -1;
+
+  /**
    * Returns the plugin instance.
    *
    * @return \Drupal\block\BlockPluginInterface
diff --git a/core/modules/block/lib/Drupal/block/BlockListController.php b/core/modules/block/lib/Drupal/block/BlockListController.php
index 30d0afd..874ff35 100644
--- a/core/modules/block/lib/Drupal/block/BlockListController.php
+++ b/core/modules/block/lib/Drupal/block/BlockListController.php
@@ -155,7 +155,7 @@ public function buildForm(array $form, array &$form_state) {
     $form['#attributes']['class'][] = 'clearfix';
 
     // Add a last region for disabled blocks.
-    $block_regions_with_disabled = $this->regions + array(BLOCK_REGION_NONE => BLOCK_REGION_NONE);
+    $block_regions_with_disabled = $this->regions + array(BlockInterface::BLOCK_REGION_NONE => BlockInterface::BLOCK_REGION_NONE);
     $form['block_regions'] = array(
       '#type' => 'value',
       '#value' => $block_regions_with_disabled,
@@ -219,7 +219,7 @@ public function buildForm(array $form, array &$form_state) {
         ),
       );
       $form['blocks'][$region]['title'] = array(
-        '#markup' => $region != BLOCK_REGION_NONE ? $title : t('Disabled'),
+        '#markup' => $region != BlockInterface::BLOCK_REGION_NONE ? $title : t('Disabled'),
         '#wrapper_attributes' => array(
           'colspan' => 5,
         ),
@@ -263,7 +263,7 @@ public function buildForm(array $form, array &$form_state) {
           $form['blocks'][$entity_id]['region-theme']['region'] = array(
             '#type' => 'select',
             '#default_value' => $region,
-            '#empty_value' => BLOCK_REGION_NONE,
+            '#empty_value' => BlockInterface::BLOCK_REGION_NONE,
             '#title' => t('Region for @block block', array('@block' => $info['admin_label'])),
             '#title_display' => 'invisible',
             '#options' => $this->regions,
@@ -404,7 +404,7 @@ public function submitForm(array &$form, array &$form_state) {
     foreach ($entities as $entity_id => $entity) {
       $entity->set('weight', $form_state['values']['blocks'][$entity_id]['weight']);
       $entity->set('region', $form_state['values']['blocks'][$entity_id]['region']);
-      if ($entity->get('region') == BLOCK_REGION_NONE) {
+      if ($entity->get('region') == BlockInterface::BLOCK_REGION_NONE) {
         $entity->disable();
       }
       else {
diff --git a/core/modules/block/lib/Drupal/block/Entity/Block.php b/core/modules/block/lib/Drupal/block/Entity/Block.php
index 67d10e4..020b970 100644
--- a/core/modules/block/lib/Drupal/block/Entity/Block.php
+++ b/core/modules/block/lib/Drupal/block/Entity/Block.php
@@ -71,7 +71,7 @@ class Block extends ConfigEntityBase implements BlockInterface {
    *
    * @var string
    */
-  protected $region = BLOCK_REGION_NONE;
+  protected $region = self::BLOCK_REGION_NONE;
 
   /**
    * The block weight.
@@ -163,7 +163,7 @@ public static function sort($a, $b) {
       return $status;
     }
     // Sort by weight, unless disabled.
-    if ($a->get('region') != BLOCK_REGION_NONE) {
+    if ($a->get('region') != static::BLOCK_REGION_NONE) {
       $weight = $a->get('weight') - $b->get('weight');
       if ($weight) {
         return $weight;
diff --git a/core/modules/block/tests/Drupal/block/Tests/BlockFormControllerTest.php b/core/modules/block/tests/Drupal/block/Tests/BlockFormControllerTest.php
index e01c9f1..8394d03 100644
--- a/core/modules/block/tests/Drupal/block/Tests/BlockFormControllerTest.php
+++ b/core/modules/block/tests/Drupal/block/Tests/BlockFormControllerTest.php
@@ -10,11 +10,6 @@
 use Drupal\block\BlockFormController;
 use Drupal\Tests\UnitTestCase;
 
-// @todo Remove once the constants are replaced with constants on classes.
-if (!defined('BLOCK_REGION_NONE')) {
-  define('BLOCK_REGION_NONE', -1);
-}
-
 /**
  * Tests the block form controller.
  *
diff --git a/core/modules/block/tests/Drupal/block/Tests/Menu/BlockLocalTasksTest.php b/core/modules/block/tests/Drupal/block/Tests/Menu/BlockLocalTasksTest.php
index 59b26f8..989a7ec 100644
--- a/core/modules/block/tests/Drupal/block/Tests/Menu/BlockLocalTasksTest.php
+++ b/core/modules/block/tests/Drupal/block/Tests/Menu/BlockLocalTasksTest.php
@@ -26,7 +26,7 @@ public static function getInfo() {
   }
 
   public function setUp() {
-    $this->moduleList = array('block' => 'core/modules/block/block.info.yml');
+    $this->moduleList = array('block' => 'core/modules/block/block.module');
     parent::setUp();
 
     $config_factory = $this->getConfigFactoryStub(array('system.theme' => array(
diff --git a/core/modules/book/tests/Drupal/book/Tests/Menu/BookLocalTasksTest.php b/core/modules/book/tests/Drupal/book/Tests/Menu/BookLocalTasksTest.php
index 2f8d749..c1f1434 100644
--- a/core/modules/book/tests/Drupal/book/Tests/Menu/BookLocalTasksTest.php
+++ b/core/modules/book/tests/Drupal/book/Tests/Menu/BookLocalTasksTest.php
@@ -27,8 +27,8 @@ public static function getInfo() {
 
   public function setUp() {
     $this->moduleList = array(
-      'book' => 'core/modules/book/book.info.yml',
-      'node' => 'core/modules/node/node.info.yml',
+      'book' => 'core/modules/book/book.module',
+      'node' => 'core/modules/node/node.module',
     );
     parent::setUp();
   }
diff --git a/core/modules/config/tests/Drupal/config/Tests/Menu/ConfigLocalTasksTest.php b/core/modules/config/tests/Drupal/config/Tests/Menu/ConfigLocalTasksTest.php
index ad00f10..43640c5 100644
--- a/core/modules/config/tests/Drupal/config/Tests/Menu/ConfigLocalTasksTest.php
+++ b/core/modules/config/tests/Drupal/config/Tests/Menu/ConfigLocalTasksTest.php
@@ -26,7 +26,7 @@ public static function getInfo() {
   }
 
   public function setUp() {
-    $this->moduleList = array('config' => 'core/modules/config/config.info.yml');
+    $this->moduleList = array('config' => 'core/modules/config/config.module');
     parent::setUp();
   }
 
diff --git a/core/modules/content_translation/lib/Drupal/content_translation/Plugin/Derivative/ContentTranslationLocalTasks.php b/core/modules/content_translation/lib/Drupal/content_translation/Plugin/Derivative/ContentTranslationLocalTasks.php
index 558bdfd..f87ff77 100644
--- a/core/modules/content_translation/lib/Drupal/content_translation/Plugin/Derivative/ContentTranslationLocalTasks.php
+++ b/core/modules/content_translation/lib/Drupal/content_translation/Plugin/Derivative/ContentTranslationLocalTasks.php
@@ -120,15 +120,15 @@ public function alterLocalTasks(array &$local_tasks) {
    *   Returns the local task ID of the parent task, otherwise return FALSE.
    */
   protected function getTaskFromRoute($route_name, &$local_tasks) {
-    $local_task = FALSE;
+    $parent_local_task = FALSE;
     foreach ($local_tasks as $plugin_id => $local_task) {
       if ($local_task['route_name'] == $route_name) {
-        $local_task = $plugin_id;
+        $parent_local_task = $plugin_id;
         break;
       }
     }
 
-    return $local_task;
+    return $parent_local_task;
   }
 
   /**
diff --git a/core/modules/content_translation/tests/Drupal/content_translation/Tests/Menu/ContentTranslationLocalTasksTest.php b/core/modules/content_translation/tests/Drupal/content_translation/Tests/Menu/ContentTranslationLocalTasksTest.php
index cde6985..7b0c1c0 100644
--- a/core/modules/content_translation/tests/Drupal/content_translation/Tests/Menu/ContentTranslationLocalTasksTest.php
+++ b/core/modules/content_translation/tests/Drupal/content_translation/Tests/Menu/ContentTranslationLocalTasksTest.php
@@ -27,8 +27,8 @@ public static function getInfo() {
 
   public function setUp() {
     $this->moduleList = array(
-      'content_translation' => 'core/modules/content_translation/content_translation.info.yml',
-      'node' => 'core/modules/node/node.info.yml',
+      'content_translation' => 'core/modules/content_translation/content_translation.module',
+      'node' => 'core/modules/node/node.module',
     );
     parent::setUp();
 
diff --git a/core/modules/language/tests/Drupal/language/Tests/Menu/LanguageLocalTasks.php b/core/modules/language/tests/Drupal/language/Tests/Menu/LanguageLocalTasks.php
index 36ea469..cd3cd2f 100644
--- a/core/modules/language/tests/Drupal/language/Tests/Menu/LanguageLocalTasks.php
+++ b/core/modules/language/tests/Drupal/language/Tests/Menu/LanguageLocalTasks.php
@@ -27,7 +27,7 @@ public static function getInfo() {
 
   public function setUp() {
     $this->moduleList = array(
-      'language' => 'core/modules/language/language.info.yml',
+      'language' => 'core/modules/language/language.module',
     );
     parent::setUp();
   }
diff --git a/core/modules/locale/tests/Drupal/locale/Tests/Menu/LocaleLocalTasksTest.php b/core/modules/locale/tests/Drupal/locale/Tests/Menu/LocaleLocalTasksTest.php
index 4c18831..f8db54f 100644
--- a/core/modules/locale/tests/Drupal/locale/Tests/Menu/LocaleLocalTasksTest.php
+++ b/core/modules/locale/tests/Drupal/locale/Tests/Menu/LocaleLocalTasksTest.php
@@ -27,7 +27,7 @@ public static function getInfo() {
 
   public function setUp() {
     $this->moduleList = array(
-      'locale' => 'core/modules/locale/locale.info.yml',
+      'locale' => 'core/modules/locale/locale.module',
     );
     parent::setUp();
   }
diff --git a/core/modules/shortcut/tests/Drupal/shortcut/Tests/Menu/ShortcutLocalTasksTest.php b/core/modules/shortcut/tests/Drupal/shortcut/Tests/Menu/ShortcutLocalTasksTest.php
index ff8bd7e..edc5e8b 100644
--- a/core/modules/shortcut/tests/Drupal/shortcut/Tests/Menu/ShortcutLocalTasksTest.php
+++ b/core/modules/shortcut/tests/Drupal/shortcut/Tests/Menu/ShortcutLocalTasksTest.php
@@ -27,8 +27,8 @@ public static function getInfo() {
 
   public function setUp() {
     $this->moduleList = array(
-      'shortcut' => 'core/modules/shortcut/shortcut.info.yml',
-      'user' => 'core/modules/user/user.info.yml',
+      'shortcut' => 'core/modules/shortcut/shortcut.module',
+      'user' => 'core/modules/user/user.module',
     );
     parent::setUp();
   }
diff --git a/core/modules/taxonomy/tests/Drupal/taxonomy/Tests/Menu/TaxonomyLocalTasksTest.php b/core/modules/taxonomy/tests/Drupal/taxonomy/Tests/Menu/TaxonomyLocalTasksTest.php
index 6151cb2..52708a4 100644
--- a/core/modules/taxonomy/tests/Drupal/taxonomy/Tests/Menu/TaxonomyLocalTasksTest.php
+++ b/core/modules/taxonomy/tests/Drupal/taxonomy/Tests/Menu/TaxonomyLocalTasksTest.php
@@ -26,7 +26,7 @@ public static function getInfo() {
   }
 
   public function setUp() {
-    $this->moduleList = array('taxonomy' => 'core/modules/taxonomy/taxonomy.info.yml');
+    $this->moduleList = array('taxonomy' => 'core/modules/taxonomy/taxonomy.module');
     parent::setUp();
   }
 
diff --git a/core/modules/user/tests/Drupal/user/Tests/Menu/UserLocalTasksTest.php b/core/modules/user/tests/Drupal/user/Tests/Menu/UserLocalTasksTest.php
index a978178..5fb9f40 100644
--- a/core/modules/user/tests/Drupal/user/Tests/Menu/UserLocalTasksTest.php
+++ b/core/modules/user/tests/Drupal/user/Tests/Menu/UserLocalTasksTest.php
@@ -26,7 +26,7 @@ public static function getInfo() {
   }
 
   public function setUp() {
-    $this->moduleList = array('user' => 'core/modules/user/user.info.yml');
+    $this->moduleList = array('user' => 'core/modules/user/user.module');
     parent::setUp();
   }