diff --git a/core/includes/bootstrap.inc b/core/includes/bootstrap.inc
index cf0e3dd..3230171 100644
--- a/core/includes/bootstrap.inc
+++ b/core/includes/bootstrap.inc
@@ -2554,12 +2554,12 @@ function language_default_locked_languages($weight = 0) {
  * @param string $langcode
  *   The language code.
  *
- * @return Drupal\core\Language\Language | FALSE
- *   A fully-populated language object or FALSE.
+ * @return Drupal\core\Language\Language|null
+ *   A fully-populated language object or NULL.
  */
 function language_load($langcode) {
   $languages = language_list(Language::STATE_ALL);
-  return isset($languages[$langcode]) ? $languages[$langcode] : FALSE;
+  return isset($languages[$langcode]) ? $languages[$langcode] : NULL;
 }
 
 /**
diff --git a/core/includes/menu.inc b/core/includes/menu.inc
index 6038fa5..a3ba8e7 100644
--- a/core/includes/menu.inc
+++ b/core/includes/menu.inc
@@ -559,7 +559,7 @@ function _menu_load_objects(&$item, &$map) {
           $return = $function($value);
         }
         // If callback returned an error or there is no callback, trigger 404.
-        if ($return === FALSE) {
+        if (empty($return)) {
           $item['access'] = FALSE;
           $map = FALSE;
           return FALSE;
diff --git a/core/modules/block/custom_block/custom_block.module b/core/modules/block/custom_block/custom_block.module
index e290cd4..94688ee 100644
--- a/core/modules/block/custom_block/custom_block.module
+++ b/core/modules/block/custom_block/custom_block.module
@@ -125,8 +125,8 @@ function custom_block_theme($existing, $type, $theme, $path) {
  * @param int $id
  *   The ID of the custom block type to load.
  *
- * @return Drupal\custom_block\Plugin\Core\Entity\CustomBlockType|false
- *   A CustomBlockType object or FALSE if the requested $id does not exist.
+ * @return Drupal\custom_block\Plugin\Core\Entity\CustomBlockType|null
+ *   A CustomBlockType object or NULL if the requested $id does not exist.
  */
 function custom_block_type_load($id) {
   return entity_load('custom_block_type', $id);
@@ -138,8 +138,8 @@ function custom_block_type_load($id) {
  * @param int $id
  *   The id of the custom block.
  *
- * @return Drupal\custom_block\Plugin\Core\Entity\CustomBlock|false
- *   A CustomBlock object or FALSE if the requested $id does not exist.
+ * @return Drupal\custom_block\Plugin\Core\Entity\CustomBlock|null
+ *   A CustomBlock object or NULL if the requested $id does not exist.
  */
 function custom_block_load($id) {
   return entity_load('custom_block', $id);
diff --git a/core/modules/breakpoint/breakpoint.module b/core/modules/breakpoint/breakpoint.module
index b467011..9384b2a 100644
--- a/core/modules/breakpoint/breakpoint.module
+++ b/core/modules/breakpoint/breakpoint.module
@@ -294,8 +294,8 @@ function breakpoint_get_module_media_queries($module) {
  * @param string $id
  *   The id of the breakpoint group to load.
  *
- * @return Drupal\breakpoint\Plugin\Core\Entity\BreakpointGroup|false
- *   The breakpoint group, or FALSE if there is no entity with the given id.
+ * @return Drupal\breakpoint\Plugin\Core\Entity\BreakpointGroup|null
+ *   The breakpoint group, or NULL if there is no entity with the given id.
  *
  * @todo Remove this in a follow-up issue.
  * @see http://drupal.org/node/1798214
@@ -311,7 +311,7 @@ function breakpoint_group_load($id) {
  *   The id of the breakpoint to load.
  *
  * @return Drupal\breakpoint\Plugin\Core\Entity\Breakpoint
- *   The entity object, or FALSE if there is no entity with the given id.
+ *   The entity object, or NULL if there is no entity with the given id.
  *
  * @todo Remove this in a follow-up issue.
  * @see http://drupal.org/node/1798214
diff --git a/core/modules/contact/contact.module b/core/modules/contact/contact.module
index 64d97b2..d45d10b 100644
--- a/core/modules/contact/contact.module
+++ b/core/modules/contact/contact.module
@@ -232,8 +232,8 @@ function contact_field_extra_fields() {
  * @param $id
  *   The ID of the contact category to load.
  *
- * @return Drupal\contact\Plugin\Core\Entity\Category|false
- *   A Category object or FALSE if the requested $id does not exist.
+ * @return Drupal\contact\Plugin\Core\Entity\Category|null
+ *   A Category object or NULL if the requested $id does not exist.
  */
 function contact_category_load($id) {
   return entity_load('contact_category', $id);
diff --git a/core/modules/editor/editor.module b/core/modules/editor/editor.module
index a0e78a6..82c6522 100644
--- a/core/modules/editor/editor.module
+++ b/core/modules/editor/editor.module
@@ -302,8 +302,8 @@ function editor_form_filter_admin_format_submit($form, &$form_state) {
 /**
  * Loads an individual configured text editor based on text format ID.
  *
- * @return \Drupal\editor\Plugin\Core\Entity\Editor|FALSE
- *   A text editor object, or FALSE.
+ * @return \Drupal\editor\Plugin\Core\Entity\Editor|null
+ *   A text editor object, or NULL.
  */
 function editor_load($format_id) {
   // Load all the editors at once here, assuming that either no editors or more
@@ -311,7 +311,7 @@ function editor_load($format_id) {
   // formats for administrators). Loading a small number of editors all at once
   // is more efficient than loading multiple editors individually.
   $editors = entity_load_multiple('editor');
-  return isset($editors[$format_id]) ? $editors[$format_id] : FALSE;
+  return isset($editors[$format_id]) ? $editors[$format_id] : NULL;
 }
 
 /**
diff --git a/core/modules/file/file.module b/core/modules/file/file.module
index f7a7c86..5567a07 100644
--- a/core/modules/file/file.module
+++ b/core/modules/file/file.module
@@ -119,14 +119,13 @@ function file_load_multiple(array $fids = NULL, $reset = FALSE) {
  *   Whether to reset the internal file_load_multiple() cache.
  *
  * @return \Drupal\file\FileInterface
- *   A file entity or FALSE if the file was not found.
+ *   A file entity or NULL if the file was not found.
  *
  * @see hook_file_load()
  * @see file_load_multiple()
  */
 function file_load($fid, $reset = FALSE) {
-  $files = file_load_multiple(array($fid), $reset);
-  return reset($files);
+  return entity_load('file', $fid, $reset);
 }
 
 /**
diff --git a/core/modules/filter/filter.module b/core/modules/filter/filter.module
index 1b90cde..d438d01 100644
--- a/core/modules/filter/filter.module
+++ b/core/modules/filter/filter.module
@@ -163,7 +163,7 @@ function filter_menu() {
  * @return
  *   A fully-populated text format object, if the requested format exists and
  *   is enabled. If the format does not exist, or exists in the database but
- *   has been marked as disabled, FALSE is returned.
+ *   has been marked as disabled, NULL is returned.
  *
  * @see filter_format_exists()
  *
@@ -171,7 +171,7 @@ function filter_menu() {
  */
 function filter_format_load($format_id) {
   $formats = filter_formats();
-  return isset($formats[$format_id]) ? $formats[$format_id] : FALSE;
+  return isset($formats[$format_id]) ? $formats[$format_id] : NULL;
 }
 
 /**
diff --git a/core/modules/image/image.module b/core/modules/image/image.module
index 53cb813..37dbddf 100644
--- a/core/modules/image/image.module
+++ b/core/modules/image/image.module
@@ -889,7 +889,7 @@ function image_effect_definitions() {
  */
 function image_effect_definition_load($effect) {
   $definitions = image_effect_definitions();
-  return isset($definitions[$effect]) ? $definitions[$effect] : FALSE;
+  return isset($definitions[$effect]) ? $definitions[$effect] : NULL;
 }
 
 /**
@@ -907,7 +907,7 @@ function image_effect_definition_load($effect) {
  *   - "name": The name of the effect definition that powers this image effect.
  *   - "data": An array of configuration options for this image effect.
  *   Besides these keys, the entirety of the image definition is merged into
- *   the image effect array. Returns FALSE if the specified effect cannot be
+ *   the image effect array. Returns NULL if the specified effect cannot be
  *   found.
  * @see image_effect_definition_load()
  */
@@ -926,7 +926,7 @@ function image_effect_load($ieid, $style_name) {
     $effect['ieid'] = $ieid;
     return $effect;
   }
-  return FALSE;
+  return NULL;
 }
 
 /**
diff --git a/core/modules/menu/menu.module b/core/modules/menu/menu.module
index 68c3125..808c0a5 100644
--- a/core/modules/menu/menu.module
+++ b/core/modules/menu/menu.module
@@ -238,7 +238,7 @@ function menu_enable() {
  * @param $menu_name
  *   The unique name of a custom menu to load.
  * @return
- *   Array defining the custom menu, or FALSE if the menu doesn't exist.
+ *   Array defining the custom menu, or NULL if the menu doesn't exist.
  */
 function menu_load($menu_name) {
   return entity_load('menu', $menu_name);
diff --git a/core/modules/menu_link/menu_link.module b/core/modules/menu_link/menu_link.module
index 579737c..222aa83 100644
--- a/core/modules/menu_link/menu_link.module
+++ b/core/modules/menu_link/menu_link.module
@@ -31,8 +31,8 @@ function menu_link_uri(MenuLink $menu_link) {
  * @param bool $reset
  *   (optional) Whether to reset the menu_link_load_multiple() cache.
  *
- * @return \Drupal\menu_link\Plugin\Core\Entity\MenuLink|false
- *   A menu link entity, or FALSE if there is no entity with the given ID.
+ * @return \Drupal\menu_link\Plugin\Core\Entity\MenuLink|null
+ *   A menu link entity, or NULL if there is no entity with the given ID.
  */
 function menu_link_load($mlid = NULL, $reset = FALSE) {
   return entity_load('menu_link', $mlid, $reset);
diff --git a/core/modules/node/node.module b/core/modules/node/node.module
index fbdf07d..a120a9c 100644
--- a/core/modules/node/node.module
+++ b/core/modules/node/node.module
@@ -425,11 +425,11 @@ function node_types_rebuild() {
  *   The machine name of a node type to load.
  *
  * @return
- *   A node type object or FALSE if $name does not exist.
+ *   A node type object or NULL if $name does not exist.
  */
 function node_type_load($name) {
   $types = _node_types_build()->types;
-  return isset($types[$name]) ? $types[$name] : FALSE;
+  return isset($types[$name]) ? $types[$name] : NULL;
 }
 
 /**
@@ -890,12 +890,12 @@ function node_load_multiple(array $nids = NULL, $reset = FALSE) {
  *   (optional) Whether to reset the node_load_multiple() cache. Defaults to
  *   FALSE.
  *
- * @return Drupal\node\Node|false
- *   A fully-populated node entity, or FALSE if the node is not found.
+ * @return Drupal\node\Node|null
+ *   A fully-populated node entity, or NULL if the node is not found.
  */
 function node_load($nid = NULL, $reset = FALSE) {
   $entity = entity_load('node', $nid, $reset);
-  return $entity ? $entity->getBCEntity() : FALSE;
+  return $entity ? $entity->getBCEntity() : NULL;
 }
 
 /**
@@ -904,8 +904,8 @@ function node_load($nid = NULL, $reset = FALSE) {
  * @param int $nid
  *   The node revision id.
  *
- * @return Drupal\node\Node|false
- *   A fully-populated node entity, or FALSE if the node is not found.
+ * @return Drupal\node\Node|null
+ *   A fully-populated node entity, or NULL if the node is not found.
  */
 function node_revision_load($vid = NULL) {
   return entity_revision_load('node', $vid);
diff --git a/core/modules/picture/picture.module b/core/modules/picture/picture.module
index ef6ee48..08494df 100644
--- a/core/modules/picture/picture.module
+++ b/core/modules/picture/picture.module
@@ -105,7 +105,7 @@ function picture_library_info() {
  *   The id of the picture mapping to load.
  *
  * @return Drupal\picture\Picture
- *   The entity object, or FALSE if there is no entity with the given id.
+ *   The entity object, or NULL if there is no entity with the given id.
  *
  * @todo Needed for menu_callback
  *
diff --git a/core/modules/shortcut/shortcut.module b/core/modules/shortcut/shortcut.module
index a14a3e7..f06d76b 100644
--- a/core/modules/shortcut/shortcut.module
+++ b/core/modules/shortcut/shortcut.module
@@ -278,7 +278,7 @@ function shortcut_menu_link_delete($menu_link) {
  *   - 'id': The internal name of the shortcut set.
  *   - 'label': The title of the shortcut set.
  *   - 'links': An array of links associated with this shortcut set.
- *   If the shortcut set does not exist, the function returns FALSE.
+ *   If the shortcut set does not exist, the function returns NULL.
  */
 function shortcut_set_load($id) {
   return entity_load('shortcut', $id);
diff --git a/core/modules/system/system.api.php b/core/modules/system/system.api.php
index e9e69c5..4b26440 100644
--- a/core/modules/system/system.api.php
+++ b/core/modules/system/system.api.php
@@ -663,9 +663,9 @@ function hook_menu_get_item_alter(&$router_item, $path, $original_map) {
  * This 'abc' object will then be passed into the callback functions defined
  * for the menu item, such as the page callback function mymodule_abc_edit()
  * to replace the integer 1 in the argument array. Note that a load function
- * should return FALSE when it is unable to provide a loadable object. For
+ * should return NULL when it is unable to provide a loadable object. For
  * example, the node_load() function for the 'node/%node/edit' menu item will
- * return FALSE for the path 'node/999/edit' if a node with a node ID of 999
+ * return NULL for the path 'node/999/edit' if a node with a node ID of 999
  * does not exist. The menu routing system will return a 404 error in this case.
  *
  * @subsection sub_argument_wildcards Argument Wildcards
diff --git a/core/modules/system/tests/modules/entity_test/entity_test.module b/core/modules/system/tests/modules/entity_test/entity_test.module
index 55d0dac..5f2c46f 100644
--- a/core/modules/system/tests/modules/entity_test/entity_test.module
+++ b/core/modules/system/tests/modules/entity_test/entity_test.module
@@ -285,7 +285,7 @@ function entity_test_edit(EntityInterface $entity) {
  *   A boolean indicating that the internal cache should be reset.
  *
  * @return \Drupal\entity_test\Plugin\Core\Entity\EntityTest
- *   The loaded entity object, or FALSE if the entity cannot be loaded.
+ *   The loaded entity object, or NULL if the entity cannot be loaded.
  */
 function entity_test_load($id, $reset = FALSE) {
   return entity_load('entity_test', $id, $reset);
@@ -300,7 +300,7 @@ function entity_test_load($id, $reset = FALSE) {
  *   A boolean indicating that the internal cache should be reset.
  *
  * @return \Drupal\entity_test\Plugin\Core\Entity\EntityTestRev
- *   The loaded entity object, or FALSE if the entity cannot be loaded.
+ *   The loaded entity object, or NULL if the entity cannot be loaded.
  */
 function entity_test_rev_load($id, $reset = FALSE) {
   return entity_load('entity_test_rev', $id, $reset);
@@ -330,7 +330,7 @@ function entity_test_mul_load($id, $reset = FALSE) {
  *   A boolean indicating that the internal cache should be reset.
  *
  * @return \Drupal\entity_test\Plugin\Core\Entity\EntityTestMulRev
- *   The loaded entity object, or FALSE if the entity cannot be loaded.
+ *   The loaded entity object, or NULL if the entity cannot be loaded.
  */
 function entity_test_mulrev_load($id, $reset = FALSE) {
   return entity_load('entity_test_mulrev', $id, $reset);
diff --git a/core/modules/system/tests/modules/menu_test/menu_test.module b/core/modules/system/tests/modules/menu_test/menu_test.module
index efafe6b..e1b25ab 100644
--- a/core/modules/system/tests/modules/menu_test/menu_test.module
+++ b/core/modules/system/tests/modules/menu_test/menu_test.module
@@ -513,12 +513,12 @@ function menu_test_menu_local_tasks_alter(&$data, $router_item, $root_path) {
  *   A parameter passed in via the URL.
  *
  * @return false
- *   Always return FALSE.
+ *   Always return NULL.
  *
  * @see menu_test_menu();
  */
 function menu_test_argument_load($arg1) {
-  return FALSE;
+  return NULL;
 }
 
 /**
@@ -528,12 +528,12 @@ function menu_test_argument_load($arg1) {
  *   A parameter passed in via the URL.
  *
  * @return false
- *   Always return FALSE.
+ *   Always return NULL.
  *
  * @see menu_test_menu();
  */
 function menu_test_other_argument_load($arg1) {
-  return FALSE;
+  return NULL;
 }
 
 /**
diff --git a/core/modules/taxonomy/taxonomy.module b/core/modules/taxonomy/taxonomy.module
index b2c6b83..d6b997c 100644
--- a/core/modules/taxonomy/taxonomy.module
+++ b/core/modules/taxonomy/taxonomy.module
@@ -835,8 +835,8 @@ function taxonomy_vocabulary_sort(array &$vocabularies = array()) {
  * @param int $vid
  *   The vocabulary's ID.
  *
- * @return Drupal\taxonomy\Plugin\Core\Entity\Vocabulary|false
- *   The taxonomy vocabulary entity, if exists, FALSE otherwise. Results are
+ * @return Drupal\taxonomy\Plugin\Core\Entity\Vocabulary|null
+ *   The taxonomy vocabulary entity, if exists, NULL otherwise. Results are
  *   statically cached.
  */
 function taxonomy_vocabulary_load($vid) {
@@ -849,13 +849,13 @@ function taxonomy_vocabulary_load($vid) {
  * @param $tid
  *   A term's ID
  *
- * @return Drupal\taxonomy\Plugin\Core\Entity\Term|false
- *   A taxonomy term entity, or FALSE if the term was not found. Results are
+ * @return Drupal\taxonomy\Plugin\Core\Entity\Term|null
+ *   A taxonomy term entity, or NULL if the term was not found. Results are
  *   statically cached.
  */
 function taxonomy_term_load($tid) {
   if (!is_numeric($tid)) {
-    return FALSE;
+    return NULL;
   }
   return entity_load('taxonomy_term', $tid);
 }
diff --git a/core/modules/user/user.module b/core/modules/user/user.module
index e7ee37a..317df36 100644
--- a/core/modules/user/user.module
+++ b/core/modules/user/user.module
@@ -302,14 +302,14 @@ function user_load_multiple(array $uids = NULL, $reset = FALSE) {
  *   (default) to load from the internal cache, if set.
  *
  * @return object
- *   A fully-loaded user object upon successful user load, or FALSE if the user
+ *   A fully-loaded user object upon successful user load, or NULL if the user
  *   cannot be loaded.
  *
  * @see user_load_multiple()
  */
 function user_load($uid, $reset = FALSE) {
   $user = entity_load('user', $uid, $reset);
-  return $user ? $user->getBCEntity() : FALSE;
+  return $user ? $user->getBCEntity() : NULL;
 }
 
 /**
@@ -1098,7 +1098,7 @@ function user_uid_only_optional_to_arg($arg) {
  *   An optional user ID of the user to load. If not provided, the current
  *   user's ID will be used.
  * @return
- *   A fully-loaded $user object upon successful user load, FALSE if user
+ *   A fully-loaded $user object upon successful user load, NULL if user
  *   cannot be loaded.
  *
  * @see user_load()
@@ -1866,7 +1866,7 @@ function user_roles($membersonly = FALSE, $permission = NULL) {
  *   A string representing the role ID.
  *
  * @return
- *   A fully-loaded role object if a role with the given ID exists, or FALSE
+ *   A fully-loaded role object if a role with the given ID exists, or NULL
  *   otherwise.
  */
 function user_role_load($rid) {