diff --git a/core/includes/bootstrap.inc b/core/includes/bootstrap.inc
index 56e5f43..3e0a14b 100644
--- a/core/includes/bootstrap.inc
+++ b/core/includes/bootstrap.inc
@@ -2040,7 +2040,8 @@ function drupal_array_merge_deep_array($arrays) {
 /**
  * Generates a default anonymous $user object.
  *
- * @return Object - the user object.
+ * @return Drupal\user\User
+ *   The user object.
  */
 function drupal_anonymous_user() {
   $user = new stdClass();
@@ -3346,7 +3347,7 @@ function registry_update() {
  *
  * Example:
  * @code
- * function user_access($string, $account = NULL) {
+ * function user_access($string, User $account = NULL) {
  *   // Use the advanced drupal_static() pattern, since this is called very often.
  *   static $drupal_static_fast;
  *   if (!isset($drupal_static_fast)) {
diff --git a/core/includes/password.inc b/core/includes/password.inc
index b052a4a..f89156d 100644
--- a/core/includes/password.inc
+++ b/core/includes/password.inc
@@ -13,6 +13,8 @@
  * user_needs_new_hash() functions.
  */
 
+use Drupal\user\User;
+
 /**
  * The standard log2 number of iterations for password stretching. This should
  * increase by 1 every Drupal version in order to counteract increases in the
@@ -221,13 +223,13 @@ function user_hash_password($password, $count_log2 = 0) {
  *
  * @param $password
  *   A plain-text password
- * @param $account
+ * @param Drupal\user\User $account
  *   A user object with at least the fields from the {users} table.
  *
  * @return
  *   TRUE or FALSE.
  */
-function user_check_password($password, $account) {
+function user_check_password($password, User $account) {
   if (substr($account->pass, 0, 2) == 'U$') {
     // This may be an updated password from user_update_7000(). Such hashes
     // have 'U' added as the first character and need an extra md5() (see the
@@ -270,13 +272,13 @@ function user_check_password($password, $account) {
  * Alternative implementations of this function might use other criteria based
  * on the fields in $account.
  *
- * @param $account
+ * @param Drupal\user\User $account
  *   A user object with at least the fields from the {users} table.
  *
  * @return
  *   TRUE or FALSE.
  */
-function user_needs_new_hash($account) {
+function user_needs_new_hash(User $account) {
   // Check whether this was an updated password.
   if ((substr($account->pass, 0, 3) != '$S$') || (strlen($account->pass) != DRUPAL_HASH_LENGTH)) {
     return TRUE;
diff --git a/core/modules/block/block.module b/core/modules/block/block.module
index 2592137..63fd9d2 100644
--- a/core/modules/block/block.module
+++ b/core/modules/block/block.module
@@ -5,6 +5,8 @@
  * Controls the visual building blocks a page is constructed with.
  */
 
+use Drupal\user\User;
+
 /**
  * Denotes that a block is not enabled in any region and should not be shown.
  */
@@ -641,7 +643,7 @@ function block_field_extra_fields() {
 /**
  * Implements hook_user_presave().
  */
-function block_user_presave($account) {
+function block_user_presave(User $account) {
   if (isset($account->block)) {
     $account->data['block'] = $account->block;
   }
diff --git a/core/modules/comment/comment.module b/core/modules/comment/comment.module
index 8ab8070..4a92a65 100644
--- a/core/modules/comment/comment.module
+++ b/core/modules/comment/comment.module
@@ -1444,7 +1444,7 @@ function comment_node_search_result(Node $node) {
 /**
  * Implements hook_user_cancel().
  */
-function comment_user_cancel($edit, $account, $method) {
+function comment_user_cancel($edit, User $account, $method) {
   switch ($method) {
     case 'user_cancel_block_unpublish':
       $comments = entity_load_multiple_by_properties('comment', array('uid' => $account->uid));
@@ -1467,7 +1467,7 @@ function comment_user_cancel($edit, $account, $method) {
 /**
  * Implements hook_user_predelete().
  */
-function comment_user_predelete($account) {
+function comment_user_predelete(User $account) {
   $cids = db_query('SELECT c.cid FROM {comment} c WHERE uid = :uid', array(':uid' => $account->uid))->fetchCol();
   comment_delete_multiple($cids);
 }
diff --git a/core/modules/contact/contact.module b/core/modules/contact/contact.module
index 1ba70b9..156a072 100644
--- a/core/modules/contact/contact.module
+++ b/core/modules/contact/contact.module
@@ -5,6 +5,8 @@
  * Enables the use of personal and site-wide contact forms.
  */
 
+use Drupal\user\User;
+
 /**
  * Implements hook_help().
  */
@@ -109,12 +111,12 @@ function contact_menu() {
 /**
  * Access callback: Checks access for a user's personal contact form.
  *
- * @param $account
+ * @param Drupal\user\User $account
  *   The user object of the user whose contact form is being requested.
  *
  * @see contact_menu()
  */
-function _contact_personal_tab_access($account) {
+function _contact_personal_tab_access(User $account) {
   global $user;
 
   // Anonymous users cannot have contact forms.
@@ -233,7 +235,7 @@ function contact_form_user_profile_form_alter(&$form, &$form_state) {
 /**
  * Implements hook_user_presave().
  */
-function contact_user_presave($account) {
+function contact_user_presave(User $account) {
   $account->data['contact'] = isset($account->contact) ? $account->contact : config('contact.settings')->get('user_default_enabled');
 }
 
diff --git a/core/modules/contact/lib/Drupal/contact/Tests/ContactPersonalTest.php b/core/modules/contact/lib/Drupal/contact/Tests/ContactPersonalTest.php
index 16d26b0..539634d 100644
--- a/core/modules/contact/lib/Drupal/contact/Tests/ContactPersonalTest.php
+++ b/core/modules/contact/lib/Drupal/contact/Tests/ContactPersonalTest.php
@@ -7,6 +7,7 @@
 
 namespace Drupal\contact\Tests;
 
+use Drupal\user\User;
 use Drupal\simpletest\WebTestBase;
 
 /**
@@ -159,12 +160,12 @@ class ContactPersonalTest extends WebTestBase {
   /**
    * Fills out a user's personal contact form and submits it.
    *
-   * @param $account
+   * @param Drupal\user\User $account
    *   A user object of the user being contacted.
    * @param $message
    *   An optional array with the form fields being used.
    */
-  protected function submitPersonalContact($account, array $message = array()) {
+  protected function submitPersonalContact(User $account, array $message = array()) {
     $message += array(
       'subject' => $this->randomName(16),
       'message' => $this->randomName(64),
diff --git a/core/modules/field/field.api.php b/core/modules/field/field.api.php
index d77eca1..2b8f2a9 100644
--- a/core/modules/field/field.api.php
+++ b/core/modules/field/field.api.php
@@ -2666,13 +2666,13 @@ function hook_field_storage_purge($entity_type, $entity, $field, $instance) {
  *   The type of $entity; for example, 'node' or 'user'.
  * @param $entity
  *   (optional) The entity for the operation.
- * @param $account
+ * @param Drupal\user\User $account
  *   (optional) The account to check; if not given use currently logged in user.
  *
  * @return
  *   TRUE if the operation is allowed, and FALSE if the operation is denied.
  */
-function hook_field_access($op, $field, $entity_type, $entity, $account) {
+function hook_field_access($op, $field, $entity_type, $entity, Drupal\user\User $account) {
   if ($field['field_name'] == 'field_of_interest' && $op == 'edit') {
     return user_access('edit field of interest', $account);
   }
diff --git a/core/modules/field/field.module b/core/modules/field/field.module
index 8157971..7654b04 100644
--- a/core/modules/field/field.module
+++ b/core/modules/field/field.module
@@ -4,6 +4,7 @@
  * Attach custom data fields to Drupal entities.
  */
 
+use Drupal\user\User;
 use Drupal\entity\EntityFieldQuery;
 
 /*
@@ -995,14 +996,14 @@ function field_has_data($field) {
  *   The type of $entity; e.g., 'node' or 'user'.
  * @param $entity
  *   (optional) The entity for the operation.
- * @param $account
+ * @param Drupal\user\User $account
  *   (optional) The account to check, if not given use currently logged in user.
  *
  * @return
  *   TRUE if the operation is allowed;
  *   FALSE if the operation is denied.
  */
-function field_access($op, $field, $entity_type, $entity = NULL, $account = NULL) {
+function field_access($op, $field, $entity_type, $entity = NULL, User $account = NULL) {
   global $user;
 
   if (!isset($account)) {
diff --git a/core/modules/field/tests/modules/field_test/field_test.field.inc b/core/modules/field/tests/modules/field_test/field_test.field.inc
index 8933d8b..1d5f1b2 100644
--- a/core/modules/field/tests/modules/field_test/field_test.field.inc
+++ b/core/modules/field/tests/modules/field_test/field_test.field.inc
@@ -6,6 +6,7 @@
  */
 
 use Drupal\field\FieldException;
+use Drupal\user\User;
 
 /**
  * Implements hook_field_info().
@@ -405,7 +406,7 @@ function field_test_default_value($entity_type, $entity, $field, $instance) {
 /**
  * Implements hook_field_access().
  */
-function field_test_field_access($op, $field, $entity_type, $entity, $account) {
+function field_test_field_access($op, $field, $entity_type, $entity, User $account) {
   if ($field['field_name'] == "field_no_{$op}_access") {
     return FALSE;
   }
diff --git a/core/modules/filter/filter.module b/core/modules/filter/filter.module
index 4d9bfef..8d5b910 100644
--- a/core/modules/filter/filter.module
+++ b/core/modules/filter/filter.module
@@ -389,7 +389,7 @@ function filter_modules_disabled($modules) {
 /**
  * Retrieve a list of text formats, ordered by weight.
  *
- * @param $account
+ * @param Drupal\user\User $account
  *   (optional) If provided, only those formats that are allowed for this user
  *   account will be returned. All formats will be returned otherwise.
  * @return
@@ -398,7 +398,7 @@ function filter_modules_disabled($modules) {
  *
  * @see filter_formats_reset()
  */
-function filter_formats($account = NULL) {
+function filter_formats(User $account = NULL) {
   $language_interface = language(LANGUAGE_TYPE_INTERFACE);
   $formats = &drupal_static(__FUNCTION__, array());
 
@@ -499,7 +499,7 @@ function filter_get_formats_by_role($rid) {
  * returned by filter_fallback_format() should be used, since that is intended
  * to be a safe, consistent format that is always available to all users.
  *
- * @param $account
+ * @param Drupal\user\User $account
  *   (optional) The user account to check. Defaults to the currently logged-in
  *   user.
  * @return
@@ -507,7 +507,7 @@ function filter_get_formats_by_role($rid) {
  *
  * @see filter_fallback_format()
  */
-function filter_default_format($account = NULL) {
+function filter_default_format(User $account = NULL) {
   global $user;
   if (!isset($account)) {
     $account = $user;
@@ -981,14 +981,14 @@ function theme_text_format_wrapper($variables) {
  *
  * @param $format
  *   An object representing the text format.
- * @param $account
+ * @param Drupal\user\User $account
  *   (optional) The user account to check access for; if omitted, the currently
  *   logged-in user is used.
  *
  * @return
  *   Boolean TRUE if the user is allowed to access the given format.
  */
-function filter_access($format, $account = NULL) {
+function filter_access($format, User $account = NULL) {
   global $user;
   if (!isset($account)) {
     $account = $user;
diff --git a/core/modules/node/node.api.php b/core/modules/node/node.api.php
index a73b851..765be5d 100644
--- a/core/modules/node/node.api.php
+++ b/core/modules/node/node.api.php
@@ -181,7 +181,7 @@ use Drupal\entity\EntityInterface;
  * sure to restore your {node_access} record after node_access_rebuild() is
  * called.
  *
- * @param $account
+ * @param Drupal\user\User $account
  *   The user object whose grants are requested.
  * @param $op
  *   The node operation to be performed, such as "view", "update", or "delete".
@@ -196,7 +196,7 @@ use Drupal\entity\EntityInterface;
  * @see node_access_rebuild()
  * @ingroup node_access
  */
-function hook_node_grants($account, $op) {
+function hook_node_grants(Drupal\user\User $account, $op) {
   if (user_access('access private content', $account)) {
     $grants['example'] = array(1);
   }
@@ -363,7 +363,7 @@ function hook_node_access_records_alter(&$grants, Drupal\node\Node $node) {
  *
  * @param $grants
  *   The $grants array returned by hook_node_grants().
- * @param $account
+ * @param Drupal\user\User $account
  *   The user account requesting access to content.
  * @param $op
  *   The operation being performed, 'view', 'update' or 'delete'.
@@ -373,7 +373,7 @@ function hook_node_access_records_alter(&$grants, Drupal\node\Node $node) {
  * @see hook_node_access_records_alter()
  * @ingroup node_access
  */
-function hook_node_grants_alter(&$grants, $account, $op) {
+function hook_node_grants_alter(&$grants, Drupal\user\User $account, $op) {
   // Our sample module never allows certain roles to edit or delete
   // content. Since some other node access modules might allow this
   // permission, we expressly remove it by returning an empty $grants
@@ -594,7 +594,7 @@ function hook_node_load($nodes, $types) {
  *   - "delete"
  *   - "update"
  *   - "view"
- * @param object $account
+ * @param Drupal\user\User $account
  *   The user object to perform the access check operation on.
  * @param object $langcode
  *   The language code to perform the access check operation on.
@@ -606,7 +606,7 @@ function hook_node_load($nodes, $types) {
  *
  * @ingroup node_access
  */
-function hook_node_access($node, $op, $account, $langcode) {
+function hook_node_access($node, $op, Drupal\user\User $account, $langcode) {
   $type = is_string($node) ? $node : $node->type;
 
   $configured_types = node_permissions_get_configured_types();
diff --git a/core/modules/node/node.module b/core/modules/node/node.module
index 89032d1..20d1e4a 100644
--- a/core/modules/node/node.module
+++ b/core/modules/node/node.module
@@ -1667,7 +1667,7 @@ function node_user_cancel($edit, $account, $method) {
 /**
  * Implements hook_user_predelete().
  */
-function node_user_predelete($account) {
+function node_user_predelete(User $account) {
   // Delete nodes (current revisions).
   // @todo Introduce node_mass_delete() or make node_mass_update() more flexible.
   $nodes = db_select('node', 'n')
@@ -1723,7 +1723,7 @@ function theme_node_search_admin($variables) {
  *   The node to check.
  * @param $op
  *   (optional) The specific operation being checked. Defaults to 'view.'
- * @param object $account
+ * @param Drupal\user\User $account
  *   (optional) A user object representing the user for whom the operation is
  *   to be performed. Determines access for a user other than the current user.
  * @param $langcode
@@ -1736,7 +1736,7 @@ function theme_node_search_admin($variables) {
  *
  * @see node_menu()
  */
-function _node_revision_access(Node $node, $op = 'view', $account = NULL, $langcode = NULL) {
+function _node_revision_access(Node $node, $op = 'view', User $account = NULL, $langcode = NULL) {
   $access = &drupal_static(__FUNCTION__, array());
 
   $map = array(
@@ -2864,7 +2864,7 @@ function node_form_system_themes_admin_form_submit($form, &$form_state) {
  * @param Drupal\node\Node|string|stdClass $node
  *   The node entity on which the operation is to be performed, or the node type
  *   object, or node type string (e.g., 'forum') for the 'create' operation.
- * @param $account
+ * @param Drupal\user\User $account
  *   (optional) A user object representing the user for whom the operation is to
  *   be performed. Determines access for a user other than the current user.
  * @param $langcode
@@ -2881,7 +2881,7 @@ function node_form_system_themes_admin_form_submit($form, &$form_state) {
  *   Add langcode support to node_access schema / queries.
  *   http://drupal.org/node/1658846
  */
-function node_access($op, $node, $account = NULL, $langcode = NULL) {
+function node_access($op, $node, User $account = NULL, $langcode = NULL) {
   $rights = &drupal_static(__FUNCTION__, array());
 
   if (!$node || !in_array($op, array('view', 'update', 'delete', 'create'), TRUE)) {
@@ -2987,7 +2987,7 @@ function node_access($op, $node, $account = NULL, $langcode = NULL) {
 /**
  * Implements hook_node_access().
  */
-function node_node_access($node, $op, $account) {
+function node_node_access($node, $op, User $account) {
   $type = is_string($node) ? $node : $node->type;
 
   $configured_types = node_permissions_get_configured_types();
@@ -3080,7 +3080,7 @@ function node_permissions_get_configured_types() {
  *
  * @param $op
  *   The operation that the user is trying to perform.
- * @param $account
+ * @param Drupal\user\User $account
  *   (optional) The user object for the user performing the operation. If
  *   omitted, the current user is used.
  *
@@ -3088,7 +3088,7 @@ function node_permissions_get_configured_types() {
  *   An associative array in which the keys are realms, and the values are
  *   arrays of grants for those realms.
  */
-function node_access_grants($op, $account = NULL) {
+function node_access_grants($op, User $account = NULL) {
 
   if (!isset($account)) {
     $account = $GLOBALS['user'];
@@ -3114,7 +3114,7 @@ function node_access_grants($op, $account = NULL) {
  * 'node_access'; when this function returns TRUE, no node access joins are
  * added to the query.
  *
- * @param $account
+ * @param Drupal\user\User $account
  *   (optional) The user object for the user whose access is being checked. If
  *   omitted, the current user is used.
  *
@@ -3124,7 +3124,7 @@ function node_access_grants($op, $account = NULL) {
  * @see hook_node_grants()
  * @see _node_query_node_access_alter()
  */
-function node_access_view_all_nodes($account = NULL) {
+function node_access_view_all_nodes(User $account = NULL) {
   global $user;
   if (!$account) {
     $account = $user;
diff --git a/core/modules/node/tests/modules/node_access_test/node_access_test.module b/core/modules/node/tests/modules/node_access_test/node_access_test.module
index 402093f..13bdb21 100644
--- a/core/modules/node/tests/modules/node_access_test/node_access_test.module
+++ b/core/modules/node/tests/modules/node_access_test/node_access_test.module
@@ -14,7 +14,7 @@ use Drupal\node\Node;
 /**
  * Implements hook_node_grants().
  */
-function node_access_test_node_grants($account, $op) {
+function node_access_test_node_grants(User $account, $op) {
   $grants = array();
   // First grant a grant to the author for own content.
   $grants['node_access_test_author'] = array($account->uid);
diff --git a/core/modules/node/tests/modules/node_test/node_test.module b/core/modules/node/tests/modules/node_test/node_test.module
index bfad466..2d40199 100644
--- a/core/modules/node/tests/modules/node_test/node_test.module
+++ b/core/modules/node/tests/modules/node_test/node_test.module
@@ -7,6 +7,7 @@
  */
 
 use Drupal\node\Node;
+use Drupal\user\User;
 
 /**
  * Implements hook_node_load().
@@ -54,7 +55,7 @@ function node_test_node_view(Node $node, $view_mode) {
 /**
  * Implements hook_node_grants().
  */
-function node_test_node_grants($account, $op) {
+function node_test_node_grants(User $account, $op) {
   // Give everyone full grants so we don't break other node tests.
   // Our node access tests asserts three realms of access.
   // See testGrantAlter().
@@ -117,7 +118,7 @@ function node_test_node_access_records_alter(&$grants, Node $node) {
 /**
  * Implements hook_node_grants_alter().
  */
-function node_test_node_grants_alter(&$grants, $account, $op) {
+function node_test_node_grants_alter(&$grants, User $account, $op) {
   // Return an empty array of grants to prove that we can alter by reference.
   $grants = array();
 }
diff --git a/core/modules/openid/openid.api.php b/core/modules/openid/openid.api.php
index bd286ff..0b4064a 100644
--- a/core/modules/openid/openid.api.php
+++ b/core/modules/openid/openid.api.php
@@ -15,10 +15,10 @@
  *
  * @param $request
  *   An associative array of request parameters.
- * @param $service
+ * @param Drupal\user\User $service
  *   A service array as returned by openid_discovery().
  */
-function hook_openid_request_alter(&$request, $service) {
+function hook_openid_request_alter(&$request, Drupal\user\User $service) {
   if ($request['openid.mode'] == 'checkid_setup') {
     $request['openid.identity'] = 'http://myname.myopenid.com/';
   }
@@ -29,11 +29,11 @@ function hook_openid_request_alter(&$request, $service) {
  *
  * @param $response
  *   Response values from the OpenID Provider.
- * @param $account
+ * @param Drupal\user\User $account
  *   The Drupal user account that logged in
  *
  */
-function hook_openid_response($response, $account) {
+function hook_openid_response($response, User $account) {
   if (isset($response['openid.ns.ax'])) {
     _mymodule_store_ax_fields($response, $account);
   }
diff --git a/core/modules/openid/openid.module b/core/modules/openid/openid.module
index 51d3f5c..4a2096f 100644
--- a/core/modules/openid/openid.module
+++ b/core/modules/openid/openid.module
@@ -5,6 +5,8 @@
  * Implement OpenID Relying Party support for Drupal
  */
 
+use Drupal\user\User;
+
 /**
  * Implements hook_menu().
  */
@@ -83,7 +85,7 @@ function openid_help($path, $arg) {
 /**
  * Implements hook_user_insert().
  */
-function openid_user_insert($account) {
+function openid_user_insert(User $account) {
   if (!empty($account->openid_claimed_id)) {
     // The user has registered after trying to log in via OpenID.
     if (config('user.settings')->get('verify_mail')) {
@@ -100,7 +102,7 @@ function openid_user_insert($account) {
  *
  * Save openid_identifier to visitor cookie.
  */
-function openid_user_login(&$edit, $account) {
+function openid_user_login(&$edit, User $account) {
   if (isset($_SESSION['openid'])) {
     // The user has logged in via OpenID.
     user_cookie_save(array_intersect_key($_SESSION['openid']['user_login_values'], array_flip(array('openid_identifier'))));
@@ -113,7 +115,7 @@ function openid_user_login(&$edit, $account) {
  *
  * Delete any openid_identifier in visitor cookie.
  */
-function openid_user_logout($account) {
+function openid_user_logout(User $account) {
   if (isset($_COOKIE['Drupal_visitor_openid_identifier'])) {
     user_cookie_delete('openid_identifier');
   }
diff --git a/core/modules/openid/tests/openid_test.module b/core/modules/openid/tests/openid_test.module
index 89f3ddf..17009a3 100644
--- a/core/modules/openid/tests/openid_test.module
+++ b/core/modules/openid/tests/openid_test.module
@@ -20,6 +20,7 @@
  * key is used for verifying the signed messages from the provider.
  */
 
+use Drupal\user\User;
 use Symfony\Component\HttpFoundation\RedirectResponse;
 use Symfony\Component\HttpFoundation\Response;
 use Symfony\Component\HttpKernel\Exception\NotFoundHttpException;
@@ -362,7 +363,7 @@ function openid_test_openid_request_alter(&$request, $service) {
 /**
  * Implements hook_openid_response().
  */
-function openid_test_openid_response($response, $account) {
+function openid_test_openid_response($response, User $account) {
   variable_set('openid_test_hook_openid_response_response', $response);
   variable_set('openid_test_hook_openid_response_account', $account ? $account : FALSE);
 }
diff --git a/core/modules/overlay/overlay.module b/core/modules/overlay/overlay.module
index 3aaed7d..dc2feb6 100644
--- a/core/modules/overlay/overlay.module
+++ b/core/modules/overlay/overlay.module
@@ -5,6 +5,7 @@
  * Displays the Drupal administration interface in an overlay.
  */
 
+use Drupal\user\User;
 use Symfony\Component\HttpFoundation\Response;
 use Symfony\Component\HttpKernel\Exception\AccessDeniedHttpException;
 
@@ -105,7 +106,7 @@ function overlay_form_user_profile_form_alter(&$form, &$form_state) {
 /**
  * Implements hook_user_presave().
  */
-function overlay_user_presave($account) {
+function overlay_user_presave(User $account) {
   if (isset($account->overlay)) {
     $account->data['overlay'] = $account->overlay;
   }
diff --git a/core/modules/poll/poll.module b/core/modules/poll/poll.module
index dc4722e..849987b 100644
--- a/core/modules/poll/poll.module
+++ b/core/modules/poll/poll.module
@@ -7,6 +7,7 @@
  */
 
 use Drupal\node\Node;
+use Drupal\user\User;
 
 /**
  * Implements hook_help().
@@ -964,7 +965,7 @@ function poll_cancel($form, &$form_state) {
 /**
  * Implements hook_user_cancel().
  */
-function poll_user_cancel($edit, $account, $method) {
+function poll_user_cancel($edit, User $account, $method) {
   switch ($method) {
     case 'user_cancel_reassign':
       db_update('poll_vote')
@@ -978,7 +979,7 @@ function poll_user_cancel($edit, $account, $method) {
 /**
  * Implements hook_user_predelete().
  */
-function poll_user_predelete($account) {
+function poll_user_predelete(User $account) {
   db_delete('poll_vote')
     ->condition('uid', $account->uid)
     ->execute();
diff --git a/core/modules/rdf/lib/Drupal/rdf/Tests/CommentAttributesTest.php b/core/modules/rdf/lib/Drupal/rdf/Tests/CommentAttributesTest.php
index e765436..3cbe7ab 100644
--- a/core/modules/rdf/lib/Drupal/rdf/Tests/CommentAttributesTest.php
+++ b/core/modules/rdf/lib/Drupal/rdf/Tests/CommentAttributesTest.php
@@ -163,10 +163,10 @@ class CommentAttributesTest extends CommentTestBase {
    *
    * @param $comment
    *   Comment object.
-   * @param $account
+   * @param Drupal\user\User $account
    *   An array containing information about an anonymous user.
    */
-  function _testBasicCommentRdfaMarkup($comment, $account = array()) {
+  function _testBasicCommentRdfaMarkup($comment, User $account) {
     $comment_container = $this->xpath('//div[contains(@class, "comment") and contains(@typeof, "sioct:Comment")]');
     $this->assertTrue(!empty($comment_container), t("Comment RDF type for comment found."));
     $comment_title = $this->xpath('//div[contains(@class, "comment") and contains(@typeof, "sioct:Comment")]//h3[@property="dc:title"]');
diff --git a/core/modules/shortcut/shortcut.admin.inc b/core/modules/shortcut/shortcut.admin.inc
index 3345c59..4fe6ab4 100644
--- a/core/modules/shortcut/shortcut.admin.inc
+++ b/core/modules/shortcut/shortcut.admin.inc
@@ -5,6 +5,7 @@
  * Administrative page callbacks for the shortcut module.
  */
 
+use Drupal\user\User;
 use Symfony\Component\HttpKernel\Exception\AccessDeniedHttpException;
 
 /**
@@ -14,7 +15,7 @@ use Symfony\Component\HttpKernel\Exception\AccessDeniedHttpException;
  *   An associative array containing the structure of the form.
  * @param $form_state
  *   An associative array containing the current state of the form.
- * @param $account
+ * @param Drupal\user\User $account
  *   (optional) The user account whose shortcuts will be switched. Defaults to
  *   the current logged-in user.
  *
@@ -25,7 +26,7 @@ use Symfony\Component\HttpKernel\Exception\AccessDeniedHttpException;
  * @see shortcut_set_switch_validate()
  * @see shortcut_set_switch_submit()
  */
-function shortcut_set_switch($form, &$form_state, $account = NULL) {
+function shortcut_set_switch($form, &$form_state, User $account = NULL) {
   global $user;
   if (!isset($account)) {
     $account = $user;
diff --git a/core/modules/shortcut/shortcut.api.php b/core/modules/shortcut/shortcut.api.php
index 2fcbdc9..d653710 100644
--- a/core/modules/shortcut/shortcut.api.php
+++ b/core/modules/shortcut/shortcut.api.php
@@ -24,13 +24,13 @@
  * modules implement this hook, the last (i.e., highest weighted) module which
  * returns a valid shortcut set name will prevail.
  *
- * @param $account
+ * @param Drupal\user\User $account
  *   The user account whose default shortcut set is being requested.
  * @return
  *   The name of the shortcut set that this module recommends for that user, if
  *   there is one.
  */
-function hook_shortcut_default_set($account) {
+function hook_shortcut_default_set(Drupal\user\User $account) {
   // Use a special set of default shortcuts for administrators only.
   if (in_array(config('user.settings')->get('admin_role'), $account->roles)) {
     return variable_get('mymodule_shortcut_admin_default_set');
diff --git a/core/modules/shortcut/shortcut.module b/core/modules/shortcut/shortcut.module
index 27eb8c2..2dedf76 100644
--- a/core/modules/shortcut/shortcut.module
+++ b/core/modules/shortcut/shortcut.module
@@ -5,6 +5,8 @@
  * Allows users to manage customizable lists of shortcut links.
  */
 
+use Drupal\user\User;
+
 /**
  * The name of the default shortcut set.
  *
@@ -256,7 +258,7 @@ function shortcut_set_delete_access($shortcut_set) {
 /**
  * Access callback for switching the shortcut set assigned to a user account.
  *
- * @param object $account
+ * @param Drupal\user\User $account
  *   (optional) The user account whose shortcuts will be switched. If not set,
  *   permissions will be checked for switching the logged-in user's own
  *   shortcut set.
@@ -265,7 +267,7 @@ function shortcut_set_delete_access($shortcut_set) {
  *   TRUE if the current user has access to switch the shortcut set of the
  *   provided account, FALSE otherwise.
  */
-function shortcut_set_switch_access($account = NULL) {
+function shortcut_set_switch_access(User $account = NULL) {
   global $user;
 
   if (user_access('administer shortcuts')) {
@@ -435,10 +437,10 @@ function shortcut_set_reset_link_weights(&$shortcut_set) {
  *
  * @param $shortcut_set
  *   An object representing the shortcut set.
- * @param $account
+ * @param Drupal\user\User $account
  *   A user account that will be assigned to use the set.
  */
-function shortcut_set_assign_user($shortcut_set, $account) {
+function shortcut_set_assign_user($shortcut_set, User $account) {
   db_merge('shortcut_set_users')
     ->key(array('uid' => $account->uid))
     ->fields(array('set_name' => $shortcut_set->set_name))
@@ -451,7 +453,7 @@ function shortcut_set_assign_user($shortcut_set, $account) {
  *
  * The user will go back to using whatever default set applies.
  *
- * @param $account
+ * @param Drupal\user\User $account
  *   A user account that will be removed from the shortcut set assignment.
  *
  * @return
@@ -459,7 +461,7 @@ function shortcut_set_assign_user($shortcut_set, $account) {
  *   successfully removed from it. FALSE if the user was already not assigned
  *   to any set.
  */
-function shortcut_set_unassign_user($account) {
+function shortcut_set_unassign_user(User $account) {
   $deleted = db_delete('shortcut_set_users')
     ->condition('uid', $account->uid)
     ->execute();
@@ -469,7 +471,7 @@ function shortcut_set_unassign_user($account) {
 /**
  * Returns the current displayed shortcut set for the provided user account.
  *
- * @param $account
+ * @param Drupal\user\User $account
  *   (optional) The user account whose shortcuts will be returned. Defaults to
  *   the currently logged-in user.
  *
@@ -478,7 +480,7 @@ function shortcut_set_unassign_user($account) {
  *   current user. If the user does not have an explicit shortcut set defined,
  *   the default set is returned.
  */
-function shortcut_current_displayed_set($account = NULL) {
+function shortcut_current_displayed_set(Drupal\user\User $account = NULL) {
   $shortcut_sets = &drupal_static(__FUNCTION__, array());
   global $user;
   if (!isset($account)) {
@@ -510,7 +512,7 @@ function shortcut_current_displayed_set($account = NULL) {
 /**
  * Returns the default shortcut set for a given user account.
  *
- * @param object $account
+ * @param Drupal\user\User $account
  *   (optional) The user account whose default shortcut set will be returned.
  *   If not provided, the function will return the currently logged-in user's
  *   default shortcut set.
@@ -518,7 +520,7 @@ function shortcut_current_displayed_set($account = NULL) {
  * @return
  *   An object representing the default shortcut set.
  */
-function shortcut_default_set($account = NULL) {
+function shortcut_default_set(User $account = NULL) {
   global $user;
   if (!isset($account)) {
     $account = $user;
diff --git a/core/modules/simpletest/lib/Drupal/simpletest/WebTestBase.php b/core/modules/simpletest/lib/Drupal/simpletest/WebTestBase.php
index 25139e6..52117a4 100644
--- a/core/modules/simpletest/lib/Drupal/simpletest/WebTestBase.php
+++ b/core/modules/simpletest/lib/Drupal/simpletest/WebTestBase.php
@@ -369,7 +369,7 @@ abstract class WebTestBase extends TestBase {
    *   Array of permission names to assign to user. Note that the user always
    *   has the default permissions derived from the "authenticated users" role.
    *
-   * @return object|false
+   * @return \Drupal\user\User|false
    *   A fully loaded user object with pass_raw property, or FALSE if account
    *   creation fails.
    */
@@ -515,7 +515,7 @@ abstract class WebTestBase extends TestBase {
    *   $account->pass_raw = $pass_raw;
    * @endcode
    *
-   * @param $user
+   * @param \Drupal\user\User $user
    *   User object representing the user to log in.
    *
    * @see drupalCreateUser()
diff --git a/core/modules/statistics/lib/Drupal/statistics/Tests/StatisticsAdminTest.php b/core/modules/statistics/lib/Drupal/statistics/Tests/StatisticsAdminTest.php
index a24ec95..92ceff6 100644
--- a/core/modules/statistics/lib/Drupal/statistics/Tests/StatisticsAdminTest.php
+++ b/core/modules/statistics/lib/Drupal/statistics/Tests/StatisticsAdminTest.php
@@ -24,7 +24,7 @@ class StatisticsAdminTest extends WebTestBase {
   /**
    * A user that has permission to administer and access statistics.
    *
-   * @var object|FALSE
+   * @var \Drupal\user\User|false
    *
    * A fully loaded user object, or FALSE if user creation failed.
    */
diff --git a/core/modules/statistics/statistics.module b/core/modules/statistics/statistics.module
index 35f625a..b9cd00c 100644
--- a/core/modules/statistics/statistics.module
+++ b/core/modules/statistics/statistics.module
@@ -6,6 +6,7 @@
  */
 
 use Drupal\node\Node;
+use Drupal\user\User;
 
 /**
  * Implements hook_help().
@@ -206,7 +207,7 @@ function statistics_menu() {
 /**
  * Implements hook_user_cancel().
  */
-function statistics_user_cancel($edit, $account, $method) {
+function statistics_user_cancel($edit, User $account, $method) {
   switch ($method) {
     case 'user_cancel_reassign':
       db_update('accesslog')
@@ -220,7 +221,7 @@ function statistics_user_cancel($edit, $account, $method) {
 /**
  * Implements hook_user_predelete().
  */
-function statistics_user_predelete($account) {
+function statistics_user_predelete(User $account) {
   db_delete('accesslog')
     ->condition('uid', $account->uid)
     ->execute();
diff --git a/core/modules/system/system.module b/core/modules/system/system.module
index de7241f..30bb8d7 100644
--- a/core/modules/system/system.module
+++ b/core/modules/system/system.module
@@ -5,6 +5,7 @@
  * Configuration system that lets administrators modify the workings of the site.
  */
 
+use Drupal\user\User;
 use Drupal\Core\Utility\ModuleInfo;
 
 use Symfony\Component\HttpFoundation\JsonResponse;
@@ -2237,7 +2238,7 @@ function system_form_user_register_form_alter(&$form, &$form_state) {
 /**
  * Implements hook_user_presave().
  */
-function system_user_presave($account) {
+function system_user_presave(User $account) {
   if (variable_get('configurable_timezones', 1) && empty($account->timezone) && !variable_get('user_default_timezone', DRUPAL_USER_TIMEZONE_DEFAULT)) {
     $account->timezone = variable_get('date_default_timezone', '');
   }
@@ -2246,7 +2247,7 @@ function system_user_presave($account) {
 /**
  * Implements hook_user_login().
  */
-function system_user_login(&$edit, $account) {
+function system_user_login(&$edit, User $account) {
   // If the user has a NULL time zone, notify them to set a time zone.
   if (!$account->timezone && variable_get('configurable_timezones', 1) && variable_get('empty_timezone_message', 0)) {
     drupal_set_message(t('Configure your <a href="@user-edit">account time zone setting</a>.', array('@user-edit' => url("user/$account->uid/edit", array('query' => drupal_get_destination(), 'fragment' => 'edit-timezone')))));
diff --git a/core/modules/system/tests/modules/session_test/session_test.module b/core/modules/system/tests/modules/session_test/session_test.module
index 689ff09..c1fe030 100644
--- a/core/modules/system/tests/modules/session_test/session_test.module
+++ b/core/modules/system/tests/modules/session_test/session_test.module
@@ -1,5 +1,7 @@
 <?php
 
+use Drupal\user\User;
+
 /**
  * Implements hook_menu().
  */
@@ -153,7 +155,7 @@ function _session_test_set_not_started() {
 /**
  * Implements hook_user().
  */
-function session_test_user_login($edit = array(), $user = NULL) {
+function session_test_user_login($edit = array(), User $user = NULL) {
   if ($user->name == 'session_test_user') {
     // Exit so we can verify that the session was regenerated
     // before hook_user() was called.
diff --git a/core/modules/tracker/tracker.module b/core/modules/tracker/tracker.module
index 7060a87..f4ced98 100644
--- a/core/modules/tracker/tracker.module
+++ b/core/modules/tracker/tracker.module
@@ -157,8 +157,8 @@ function tracker_cron() {
 /**
  * Access callback: Determines access permission for a user's own account.
  *
- * @param int $account
- *   The account ID to check.
+ * @param Drupal\user\User $account
+ *   The user object to check.
  *
  * @return boolean
  *   TRUE if a user is accessing tracking info for their own account and
@@ -166,7 +166,7 @@ function tracker_cron() {
  *
  * @see tracker_menu()
  */
-function _tracker_myrecent_access($account) {
+function _tracker_myrecent_access(User $account) {
   // This path is only allowed for authenticated users looking at their own content.
   return $account->uid && ($GLOBALS['user']->uid == $account->uid) && user_access('access content');
 }
diff --git a/core/modules/tracker/tracker.pages.inc b/core/modules/tracker/tracker.pages.inc
index f012264..cc890e5 100644
--- a/core/modules/tracker/tracker.pages.inc
+++ b/core/modules/tracker/tracker.pages.inc
@@ -12,12 +12,15 @@
  * Queries the database for info, adds RDFa info if applicable, and generates
  * the render array that will be used to render the page.
  *
+ * @param Drupal\user\User $account
+ *   The account object for the user whose name is to be formatted.
+ *
  * @return array
  *   A renderable array.
  *
  * @see tracker_menu()
  */
-function tracker_page($account = NULL, $set_title = FALSE) {
+function tracker_page(User $account = NULL, $set_title = FALSE) {
   if ($account) {
     $query = db_select('tracker_user', 't')
       ->extend('Drupal\Core\Database\Query\PagerSelectExtender');
diff --git a/core/modules/user/lib/Drupal/user/Tests/UserLoginTest.php b/core/modules/user/lib/Drupal/user/Tests/UserLoginTest.php
index b5e8882..12212dc 100644
--- a/core/modules/user/lib/Drupal/user/Tests/UserLoginTest.php
+++ b/core/modules/user/lib/Drupal/user/Tests/UserLoginTest.php
@@ -7,6 +7,7 @@
 
 namespace Drupal\user\Tests;
 
+use Drupal\user\User;
 use Drupal\simpletest\WebTestBase;
 
 /**
@@ -124,13 +125,13 @@ class UserLoginTest extends WebTestBase {
   /**
    * Make an unsuccessful login attempt.
    *
-   * @param $account
-   *   A user object with name and pass_raw attributes for the login attempt.
+   * @param Drupal\user\User $account
+   *   A user entity with name and pass_raw attributes for the login attempt.
    * @param $flood_trigger
    *   Whether or not to expect that the flood control mechanism will be
    *   triggered.
    */
-  function assertFailedLogin($account, $flood_trigger = NULL) {
+  function assertFailedLogin(User $account, $flood_trigger = NULL) {
     $edit = array(
       'name' => $account->name,
       'pass' => $account->pass_raw,
diff --git a/core/modules/user/lib/Drupal/user/Tests/UserRolesAssignmentTest.php b/core/modules/user/lib/Drupal/user/Tests/UserRolesAssignmentTest.php
index eaabdd2..3884d38 100644
--- a/core/modules/user/lib/Drupal/user/Tests/UserRolesAssignmentTest.php
+++ b/core/modules/user/lib/Drupal/user/Tests/UserRolesAssignmentTest.php
@@ -83,7 +83,7 @@ class UserRolesAssignmentTest extends WebTestBase {
   /**
    * Check role on user object.
    *
-   * @param object $account
+   * @param \Drupal\user\User $account
    *   The user account to check.
    * @param string $rid
    *   The role ID to search for.
@@ -91,7 +91,7 @@ class UserRolesAssignmentTest extends WebTestBase {
    *   (optional) Whether to assert that $rid exists (TRUE) or not (FALSE).
    *   Defaults to TRUE.
    */
-  private function userLoadAndCheckRoleAssigned($account, $rid, $is_assigned = TRUE) {
+  private function userLoadAndCheckRoleAssigned(User $account, $rid, $is_assigned = TRUE) {
     $account = user_load($account->uid, TRUE);
     if ($is_assigned) {
       $this->assertTrue(array_key_exists($rid, $account->roles), t('The role is present in the user object.'));
diff --git a/core/modules/user/user.api.php b/core/modules/user/user.api.php
index 98b9887..1cf9bd6 100644
--- a/core/modules/user/user.api.php
+++ b/core/modules/user/user.api.php
@@ -42,13 +42,13 @@ function hook_user_load($users) {
  * Modules should additionally implement hook_user_cancel() to process stored
  * user data for other account cancellation methods.
  *
- * @param $account
+ * @param Drupal\user\User $account
  *   The account that is about to be deleted.
  *
  * @see hook_user_delete()
  * @see user_delete_multiple()
  */
-function hook_user_predelete($account) {
+function hook_user_predelete(Drupal\user\User $account) {
   db_delete('mytable')
     ->condition('uid', $account->uid)
     ->execute();
@@ -63,13 +63,13 @@ function hook_user_predelete($account) {
  * Modules should additionally implement hook_user_cancel() to process stored
  * user data for other account cancellation methods.
  *
- * @param $account
+ * @param Drupal\user\User $account
  *   The account that has been deleted.
  *
  * @see hook_user_predelete()
  * @see user_delete_multiple()
  */
-function hook_user_delete($account) {
+function hook_user_delete(Drupal\user\User $account) {
   drupal_set_message(t('User: @name has been deleted.', array('@name' => $account->name)));
 }
 
@@ -91,7 +91,7 @@ function hook_user_delete($account) {
  *
  * @param $edit
  *   The array of form values submitted by the user.
- * @param $account
+ * @param Drupal\user\User $account
  *   The user object on which the operation is being performed.
  * @param $method
  *   The account cancellation method.
@@ -99,7 +99,7 @@ function hook_user_delete($account) {
  * @see user_cancel_methods()
  * @see hook_user_cancel_methods_alter()
  */
-function hook_user_cancel($edit, $account, $method) {
+function hook_user_cancel($edit, Drupal\user\User $account, $method) {
   switch ($method) {
     case 'user_cancel_block_unpublish':
       // Unpublish nodes (current revisions).
@@ -182,12 +182,12 @@ function hook_user_cancel_methods_alter(&$methods) {
  * @param $name
  *   The string that user_format_name() will return.
  *
- * @param $account
+ * @param Drupal\user\User $account
  *   The account object passed to user_format_name().
  *
  * @see user_format_name()
  */
-function hook_user_format_name_alter(&$name, $account) {
+function hook_user_format_name_alter(&$name, Drupal\user\User $account) {
   // Display the user's uid instead of name.
   if (isset($account->uid)) {
     $name = t('User !uid', array('!uid' => $account->uid));
@@ -238,13 +238,13 @@ function hook_user_operations() {
  * add their properties to $account->data in order to have their data serialized
  * on save.
  *
- * @param $account
+ * @param Drupal\user\User $account
  *   The user account object.
  *
  * @see hook_user_insert()
  * @see hook_user_update()
  */
-function hook_user_presave($account) {
+function hook_user_presave(Drupal\user\User $account) {
   // Make sure that our form value 'mymodule_foo' is stored as
   // 'mymodule_bar' in the 'data' (serialized) column.
   if (isset($account->mymodule_foo)) {
@@ -255,13 +255,13 @@ function hook_user_presave($account) {
 /**
  * Respond to creation of a new user account.
  *
- * @param $account
+ * @param Drupal\user\User $account
  *   The user account object.
  *
  * @see hook_user_presave()
  * @see hook_user_update()
  */
-function hook_user_insert($account) {
+function hook_user_insert(Drupal\user\User $account) {
   db_insert('user_changes')
     ->fields(array(
       'uid' => $account->uid,
@@ -273,13 +273,13 @@ function hook_user_insert($account) {
 /**
  * Respond to updates to a user account.
  *
- * @param $account
+ * @param Drupal\user\User $account
  *   The user account object.
  *
  * @see hook_user_presave()
  * @see hook_user_insert()
  */
-function hook_user_update($account) {
+function hook_user_update(Drupal\user\User $account) {
   db_insert('user_changes')
     ->fields(array(
       'uid' => $account->uid,
@@ -293,10 +293,10 @@ function hook_user_update($account) {
  *
  * @param $edit
  *   The array of form values submitted by the user.
- * @param $account
+ * @param Drupal\user\User $account
  *   The user object on which the operation was just performed.
  */
-function hook_user_login(&$edit, $account) {
+function hook_user_login(&$edit, Drupal\user\User $account) {
   // If the user has a NULL time zone, notify them to set a time zone.
   if (!$account->timezone && variable_get('configurable_timezones', 1) && variable_get('empty_timezone_message', 0)) {
     drupal_set_message(t('Configure your <a href="@user-edit">account time zone setting</a>.', array('@user-edit' => url("user/$account->uid/edit", array('query' => drupal_get_destination(), 'fragment' => 'edit-timezone')))));
@@ -306,10 +306,10 @@ function hook_user_login(&$edit, $account) {
 /**
  * The user just logged out.
  *
- * @param $account
+ * @param Drupal\user\User $account
  *   The user object on which the operation was just performed.
  */
-function hook_user_logout($account) {
+function hook_user_logout(Drupal\user\User $account) {
   db_insert('logouts')
     ->fields(array(
       'uid' => $account->uid,
@@ -324,7 +324,7 @@ function hook_user_logout($account) {
  * The module should format its custom additions for display and add them to the
  * $account->content array.
  *
- * @param $account
+ * @param Drupal\user\User $account
  *   The user object on which the operation is being performed.
  * @param $view_mode
  *   View mode, e.g. 'full'.
@@ -334,7 +334,7 @@ function hook_user_logout($account) {
  * @see hook_user_view_alter()
  * @see hook_entity_view()
  */
-function hook_user_view($account, $view_mode, $langcode) {
+function hook_user_view(Drupal\user\User $account, $view_mode, $langcode) {
   $account->content['user_picture'] = array(
     '#markup' => theme('user_picture', array('account' => $account)),
     '#weight' => -10,
diff --git a/core/modules/user/user.module b/core/modules/user/user.module
index e90c907..b252136 100644
--- a/core/modules/user/user.module
+++ b/core/modules/user/user.module
@@ -91,11 +91,11 @@ function user_help($path, $arg) {
  * @param $edit
  *   An associative array variable containing form values to be passed
  *   as the first parameter of the hook function.
- * @param $account
+ * @param Drupal\user\User $account
  *   The user account object to be passed as the second parameter of the hook
  *   function.
  */
-function user_module_invoke($type, &$edit, $account) {
+function user_module_invoke($type, &$edit, User $account) {
   foreach (module_implements('user_' . $type) as $module) {
     $function = $module . '_user_' . $type;
     $function($edit, $account);
@@ -257,7 +257,7 @@ function user_field_extra_fields() {
  * @param string $authname
  *   The external authentication username.
  *
- * @return
+ * @return Drupal\user\User|false
  *   A fully-loaded user object if the user is found or FALSE if not found.
  */
 function user_external_load($authname) {
@@ -315,11 +315,9 @@ function user_load_multiple(array $uids = NULL, $reset = FALSE) {
  *   TRUE to reset the internal cache and load from the database; FALSE
  *   (default) to load from the internal cache, if set.
  *
- * @return object
+ * @return Drupal\user\User|false
  *   A fully-loaded user object upon successful user load, or FALSE if the user
  *   cannot be loaded.
- *
- * @see user_load_multiple()
  */
 function user_load($uid, $reset = FALSE) {
   return entity_load('user', $uid, $reset);
@@ -330,7 +328,7 @@ function user_load($uid, $reset = FALSE) {
  *
  * @param string $mail
  *   String with the account's e-mail address.
- * @return object|bool
+ * @return Drupal\user\User|false
  *   A fully-loaded $user object upon successful user load or FALSE if user
  *   cannot be loaded.
  *
@@ -346,7 +344,7 @@ function user_load_by_mail($mail) {
  *
  * @param string $name
  *   String with the account's user name.
- * @return object|bool
+ * @return Drupal\user\User|false
  *   A fully-loaded $user object upon successful user load or FALSE if user
  *   cannot be loaded.
  *
@@ -494,7 +492,7 @@ function user_role_permissions($roles = array()) {
  *
  * @param $string
  *   The permission, such as "administer nodes", being checked for.
- * @param $account
+ * @param Drupal\user\User $account
  *   (optional) The account to check, if not given use currently logged in user.
  *
  * @return
@@ -504,7 +502,7 @@ function user_role_permissions($roles = array()) {
  * way, we guarantee consistent behavior, and ensure that the superuser
  * can perform all actions.
  */
-function user_access($string, $account = NULL) {
+function user_access($string, User $account = NULL) {
   global $user;
 
   if (!isset($account)) {
@@ -684,7 +682,7 @@ function user_search_execute($keys = NULL, $conditions = NULL) {
 /**
  * Implements hook_user_view().
  */
-function user_user_view($account) {
+function user_user_view(User $account) {
   $account->content['user_picture'] = array(
     '#markup' => theme('user_picture', array('account' => $account)),
     '#weight' => -10,
@@ -908,7 +906,7 @@ function user_preprocess_block(&$variables) {
  *
  * @see hook_user_format_name_alter()
  *
- * @param $account
+ * @param Drupal\user\User $account
  *   The account object for the user whose name is to be formatted.
  *
  * @return
@@ -916,7 +914,7 @@ function user_preprocess_block(&$variables) {
  *   this result must ensure that check_plain() is called on it before it is
  *   printed to the page.
  */
-function user_format_name($account) {
+function user_format_name(User $account) {
   $name = !empty($account->name) ? $account->name : config('user.settings')->get('anonymous');
   drupal_alter('user_format_name', $name, $account);
   return $name;
@@ -1128,6 +1126,8 @@ function user_register_access() {
  *
  * @param $account
  *   Can either be a full user object or a $uid.
+ *
+ * @todo: refactor into seperate functions.
  */
 function user_view_access($account) {
   $uid = is_object($account) ? $account->uid : (int) $account;
@@ -1152,7 +1152,7 @@ function user_view_access($account) {
 /**
  * Access callback for user account editing.
  */
-function user_edit_access($account) {
+function user_edit_access(User $account) {
   return (($GLOBALS['user']->uid == $account->uid) || user_access('administer users')) && $account->uid > 0;
 }
 
@@ -1162,7 +1162,7 @@ function user_edit_access($account) {
  * Limit access to users with the 'cancel account' permission or administrative
  * users, and prevent the anonymous user from cancelling the account.
  */
-function user_cancel_access($account) {
+function user_cancel_access(User $account) {
   return ((($GLOBALS['user']->uid == $account->uid) && user_access('cancel account')) || user_access('administer users')) && $account->uid > 0;
 }
 
@@ -1472,7 +1472,7 @@ function user_uid_only_optional_to_arg($arg) {
  * @param $uid
  *   An optional user ID of the user to load. If not provided, the current
  *   user's ID will be used.
- * @return
+ * @return Drupal\user\User|false
  *   A fully-loaded $user object upon successful user load, FALSE if user
  *   cannot be loaded.
  *
@@ -1532,7 +1532,7 @@ function user_get_authmaps($authname = NULL) {
  * Save mappings of which external authentication module(s) authenticated
  * a user. Maps external usernames to user ids in the users table.
  *
- * @param $account
+ * @param Drupal\user\User $account
  *   A user object.
  * @param $authmaps
  *   An associative array with a compound key and the username as the value.
@@ -1540,7 +1540,7 @@ function user_get_authmaps($authname = NULL) {
  *   module.
  * @see user_external_login_register()
  */
-function user_set_authmaps($account, $authmaps) {
+function user_set_authmaps(User $account, $authmaps) {
   foreach ($authmaps as $key => $value) {
     $module = explode('_', $key, 2);
     if ($value) {
@@ -1815,8 +1815,8 @@ function user_external_login_register($name, $module) {
 /**
  * Generates a unique URL for a user to login and reset their password.
  *
- * @param object $account
- *   An object containing the user account.
+ * @param Drupal\user\User $account
+ *   A user object.
  * @param array $options
  *   (optional) A keyed array of settings. Supported options are:
  *   - langcode: A language code to be used when generating locale-sensitive
@@ -1826,7 +1826,7 @@ function user_external_login_register($name, $module) {
  *   A unique URL that provides a one-time log in for the user, from which
  *   they can change their password.
  */
-function user_pass_reset_url($account, $options = array()) {
+function user_pass_reset_url(User $account, $options = array()) {
   $timestamp = REQUEST_TIME;
   $url_options = array('absolute' => TRUE);
   if (isset($options['langcode'])) {
@@ -1841,7 +1841,7 @@ function user_pass_reset_url($account, $options = array()) {
 /**
  * Generates a URL to confirm an account cancellation request.
  *
- * @param object $account
+ * @param Drupal\user\User $account
  *   The user account object, which must contain at least the following
  *   properties:
  *   - uid: The user uid number.
@@ -1859,7 +1859,7 @@ function user_pass_reset_url($account, $options = array()) {
  * @see user_mail_tokens()
  * @see user_cancel_confirm()
  */
-function user_cancel_url($account, $options = array()) {
+function user_cancel_url(User $account, $options = array()) {
   $timestamp = REQUEST_TIME;
   $url_options = array('absolute' => TRUE);
   if (isset($options['langcode'])) {
@@ -1959,7 +1959,7 @@ function user_cancel($edit, $uid, $method) {
  *
  * @see user_cancel()
  */
-function _user_cancel($edit, $account, $method) {
+function _user_cancel($edit, User $account, $method) {
   global $user;
 
   switch ($method) {
@@ -2082,7 +2082,7 @@ function user_view_page($account) {
  * To theme user profiles, copy modules/user/user-profile.tpl.php
  * to your theme directory, and edit it as instructed in that file's comments.
  *
- * @param $account
+ * @param Drupal\user\User $account
  *   A user object.
  * @param $view_mode
  *   View mode, e.g. 'full'.
@@ -2093,7 +2093,7 @@ function user_view_page($account) {
  * @return
  *   An array as expected by drupal_render().
  */
-function user_view($account, $view_mode = 'full', $langcode = NULL) {
+function user_view(User $account, $view_mode = 'full', $langcode = NULL) {
   if (!isset($langcode)) {
     $langcode = language(LANGUAGE_TYPE_CONTENT)->langcode;
   }
@@ -2121,7 +2121,7 @@ function user_view($account, $view_mode = 'full', $langcode = NULL) {
 /**
  * Builds a structured array representing the profile content.
  *
- * @param $account
+ * @param Drupal\user\User $account
  *   A user object.
  * @param $view_mode
  *   View mode, e.g. 'full'.
@@ -2129,7 +2129,7 @@ function user_view($account, $view_mode = 'full', $langcode = NULL) {
  *   (optional) A language code to use for rendering. Defaults to the global
  *   content language of the current request.
  */
-function user_build_content($account, $view_mode = 'full', $langcode = NULL) {
+function user_build_content(User $account, $view_mode = 'full', $langcode = NULL) {
   if (!isset($langcode)) {
     $langcode = language(LANGUAGE_TYPE_CONTENT)->langcode;
   }
@@ -2982,13 +2982,13 @@ function theme_user_signature($variables) {
  * choose a preferred language, or is the anonymous user, the $default
  * value, or if it is not set, the site default language will be returned.
  *
- * @param $account
+ * @param Drupal\user\User $account
  *   User account to look up language for.
  * @param $default
  *   Optional default language object to return if the account
  *   has no valid language.
  */
-function user_preferred_language($account, $default = NULL) {
+function user_preferred_language(User $account, $default = NULL) {
   $language_list = language_list();
   if (!empty($account->preferred_langcode) && isset($language_list[$account->preferred_langcode])) {
     return $language_list[$account->preferred_langcode];
@@ -3018,7 +3018,7 @@ function user_preferred_language($account, $default = NULL) {
  *   - 'cancel_confirm': Account cancellation request.
  *   - 'status_canceled': Account canceled.
  *
- * @param $account
+ * @param Drupal\user\User $account
  *   The user object of the account being notified. Must contain at
  *   least the fields 'uid', 'name', and 'mail'.
  * @param $language
@@ -3028,7 +3028,7 @@ function user_preferred_language($account, $default = NULL) {
  *   The return value from drupal_mail_system()->mail(), if ends up being
  *   called.
  */
-function _user_mail_notify($op, $account, $language = NULL) {
+function _user_mail_notify($op, User $account, $language = NULL) {
   // By default, we always notify except for canceled and blocked.
   $notify = config('user.settings')->get('notify.' . $op);
   if ($notify || ($op != 'status_canceled' && $op != 'status_blocked')) {