diff --git a/core/modules/update/update.api.php b/core/modules/update/update.api.php
index b5c8120..720e04e 100644
--- a/core/modules/update/update.api.php
+++ b/core/modules/update/update.api.php
@@ -23,7 +23,7 @@
  * report. In rare cases, a module might want to alter the data associated with
  * a project already in the list.
  *
- * @param $projects
+ * @param array $projects
  *   Reference to an array of the projects installed on the system. This
  *   includes all the metadata documented in the comments below for each project
  *   (either module or theme) that is currently enabled. The array is initially
@@ -34,7 +34,7 @@
  * @see update_get_projects()
  * @see \Drupal\Core\Utility\ProjectInfo->processInfoList()
  */
-function hook_update_projects_alter(&$projects) {
+function hook_update_projects_alter(array &$projects) {
   // Hide a site-specific module from the list.
   unset($projects['site_specific_module']);
 
@@ -76,13 +76,13 @@ function hook_update_projects_alter(&$projects) {
 /**
  * Alter the information about available updates for projects.
  *
- * @param $projects
+ * @param array $projects
  *   Reference to an array of information about available updates to each
  *   project installed on the system.
  *
  * @see update_calculate_project_data()
  */
-function hook_update_status_alter(&$projects) {
+function hook_update_status_alter(array &$projects) {
   $settings = \Drupal::config('update_advanced.settings')->get('projects');
   foreach ($projects as $project => $project_info) {
     if (isset($settings[$project]) && isset($settings[$project]['check']) &&
@@ -112,7 +112,7 @@ function hook_update_status_alter(&$projects) {
  * @param string $directory
  *   The directory that the archive was extracted into.
  *
- * @return
+ * @return array
  *   If there are any problems, return an array of error messages. If there are
  *   no problems, return an empty array.
  *
diff --git a/core/modules/update/update.authorize.inc b/core/modules/update/update.authorize.inc
index 8709e56..288de45 100644
--- a/core/modules/update/update.authorize.inc
+++ b/core/modules/update/update.authorize.inc
@@ -11,6 +11,7 @@
  */
 
 use Drupal\Core\Updater\UpdaterException;
+use Drupal\Core\FileTransfer;
 
 /**
  * Updates existing projects when invoked by authorize.php.
@@ -18,10 +19,10 @@
  * Callback for system_authorized_init() in
  * update_manager_update_ready_form_submit().
  *
- * @param $filetransfer
+ * @param \Drupal\Core\FileTransfer $filetransfer
  *   The FileTransfer object created by authorize.php for use during this
  *   operation.
- * @param $projects
+ * @param array $projects
  *   A nested array of projects to install into the live webroot, keyed by
  *   project name. Each subarray contains the following keys:
  *   - project: The canonical project short name.
@@ -29,7 +30,7 @@
  *     for this project.
  *   - local_url: The locally installed location of new code to update with.
  */
-function update_authorize_run_update($filetransfer, $projects) {
+function update_authorize_run_update(FileTransfer $filetransfer, array $projects) {
   $operations = array();
   foreach ($projects as $project_info) {
     $operations[] = array(
@@ -62,7 +63,7 @@ function update_authorize_run_update($filetransfer, $projects) {
  * Callback for system_authorized_init() in
  * update_manager_install_form_submit().
  *
- * @param FileTransfer $filetransfer
+ * @param \Drupal\Core\FileTransfer $filetransfer
  *   The FileTransfer object created by authorize.php for use during this
  *   operation.
  * @param string $project
@@ -75,7 +76,7 @@ function update_authorize_run_update($filetransfer, $projects) {
  *   The URL to the locally installed temp directory where the project has
  *   already been downloaded and extracted into.
  */
-function update_authorize_run_install($filetransfer, $project, $updater_name, $local_url) {
+function update_authorize_run_install(FileTransfer $filetransfer, $project, $updater_name, $local_url) {
   $operations[] = array(
     'update_authorize_batch_copy_project',
     array(
@@ -112,12 +113,12 @@ function update_authorize_run_install($filetransfer, $project, $updater_name, $l
  * @param string $local_url
  *   The URL to the locally installed temp directory where the project has
  *   already been downloaded and extracted into.
- * @param FileTransfer $filetransfer
+ * @param \Drupal\Core\FileTransfer $filetransfer
  *   The FileTransfer object to use for performing this operation.
  * @param array $context
  *   Reference to an array used for Batch API storage.
  */
-function update_authorize_batch_copy_project($project, $updater_name, $local_url, $filetransfer, &$context) {
+function update_authorize_batch_copy_project($project, $updater_name, $local_url, FileTransfer $filetransfer, array &$context) {
 
   // Initialize some variables in the Batch API $context array.
   if (!isset($context['results']['log'])) {
@@ -180,12 +181,12 @@ function update_authorize_batch_copy_project($project, $updater_name, $local_url
  * authorize.php will render a report. Also responsible for putting the site
  * back online and clearing the update status storage after a successful update.
  *
- * @param $success
+ * @param bool $success
  *   TRUE if the batch operation was successful; FALSE if there were errors.
- * @param $results
+ * @param array $results
  *   An associative array of results from the batch operation.
  */
-function update_authorize_update_batch_finished($success, $results) {
+function update_authorize_update_batch_finished($success, array $results) {
   foreach ($results['log'] as $messages) {
     if (!empty($messages['#abort'])) {
       $success = FALSE;
@@ -246,12 +247,12 @@ function update_authorize_update_batch_finished($success, $results) {
  * authorize.php will render a report. Also responsible for putting the site
  * back online after a successful install if necessary.
  *
- * @param $success
+ * @param bool $success
  *   TRUE if the batch operation was a success; FALSE if there were errors.
- * @param $results
+ * @param array $results
  *   An associative array of results from the batch operation.
  */
-function update_authorize_install_batch_finished($success, $results) {
+function update_authorize_install_batch_finished($success, array $results) {
   foreach ($results['log'] as $messages) {
     if (!empty($messages['#abort'])) {
       $success = FALSE;
@@ -308,7 +309,7 @@ function update_authorize_install_batch_finished($success, $results) {
  *   (optional) TRUE if the operation the message is about was a success, FALSE
  *   if there were errors. Defaults to TRUE.
  */
-function _update_batch_create_message(&$project_results, $message, $success = TRUE) {
+function _update_batch_create_message(array &$project_results, $message, $success = TRUE) {
   $project_results[] = array('message' => $message, 'success' => $success);
 }
 
diff --git a/core/modules/update/update.compare.inc b/core/modules/update/update.compare.inc
index 86f7244..f36d65d 100644
--- a/core/modules/update/update.compare.inc
+++ b/core/modules/update/update.compare.inc
@@ -23,7 +23,7 @@
  * module or theme but do not visit certain pages that automatically clear this
  * data.
  *
- * @return
+ * @return array
  *   An associative array of currently enabled projects keyed by the
  *   machine-readable project short name. Each project contains:
  *   - name: The machine-readable project short name.
@@ -64,10 +64,10 @@ function update_get_projects() {
  * installed versions, and other information that is required before we can
  * compare against the available releases to produce the status report.
  *
- * @param $projects
+ * @param array $projects
  *   Array of project information from update_get_projects().
  */
-function update_process_project_info(&$projects) {
+function update_process_project_info(array &$projects) {
   foreach ($projects as $key => $project) {
     // Assume an official release until we see otherwise.
     $install_type = 'official';
@@ -123,7 +123,7 @@ function update_process_project_info(&$projects) {
  * @param array $available
  *   Data about available project releases.
  *
- * @return
+ * @return array
  *   An array of installed projects with current update status information.
  *
  * @see update_get_available()
@@ -131,7 +131,7 @@ function update_process_project_info(&$projects) {
  * @see update_process_project_info()
  * @see update_project_storage()
  */
-function update_calculate_project_data($available) {
+function update_calculate_project_data(array $available) {
   // Retrieve the projects from storage, if present.
   $projects = update_project_storage('update_project_data');
   // If $projects is empty, then the data must be rebuilt.
@@ -216,12 +216,12 @@ function update_calculate_project_data($available) {
  * version (e.g., 5.x-1.5-beta1, 5.x-1.5-beta2, and 5.x-1.5). Development
  * snapshots for a given major version are always listed last.
  *
- * @param $project_data
+ * @param array $project_data
  *   An array containing information about a specific project.
- * @param $available
+ * @param array $available
  *   Data about available project releases of a specific project.
  */
-function update_calculate_project_update_status(&$project_data, $available) {
+function update_calculate_project_update_status(array &$project_data, array $available) {
   foreach (array('title', 'link') as $attribute) {
     if (!isset($project_data[$attribute]) && isset($available[$attribute])) {
       $project_data[$attribute] = $available[$attribute];
@@ -560,11 +560,11 @@ function update_calculate_project_update_status(&$project_data, $available) {
  * 'update_available_releases' collection -- it needs to persist longer than 1
  * hour and never get invalidated just by visiting a page on the site.
  *
- * @param $key
+ * @param string $key
  *   The key of data to return. Valid options are 'update_project_data' and
  *   'update_project_projects'.
  *
- * @return
+ * @return array
  *   The stored value of the $projects array generated by
  *   update_calculate_project_data() or update_get_projects(), or an empty array
  *   when the storage is cleared.
diff --git a/core/modules/update/update.fetch.inc b/core/modules/update/update.fetch.inc
index eeb28d4..59c0e2f 100644
--- a/core/modules/update/update.fetch.inc
+++ b/core/modules/update/update.fetch.inc
@@ -72,4 +72,3 @@ function _update_cron_notify() {
     }
   }
 }
-
diff --git a/core/modules/update/update.install b/core/modules/update/update.install
index 328288b..213afc9 100644
--- a/core/modules/update/update.install
+++ b/core/modules/update/update.install
@@ -10,19 +10,18 @@
 /**
  * Implements hook_requirements().
  *
- * @return
- *   An array describing the status of the site regarding available updates. If
- *   there is no update data, only one record will be returned, indicating that
- *   the status of core can't be determined. If data is available, there will be
- *   two records: one for core, and another for all of contrib (assuming there
- *   are any contributed modules or themes enabled on the site). In addition to
- *   the fields expected by hook_requirements ('value', 'severity', and
- *   optionally 'description'), this array will contain a 'reason' attribute,
- *   which is an integer constant to indicate why the given status is being
- *   returned (UPDATE_NOT_SECURE, UPDATE_NOT_CURRENT, or UPDATE_UNKNOWN). This
- *   is used for generating the appropriate email notification messages during
- *   update_cron(), and might be useful for other modules that invoke
- *   update_requirements() to find out if the site is up to date or not.
+ * Returns an array describing the status of the site regarding available
+ * updates. If there is no update data, only one record will be returned,
+ * indicating that the status of core can't be determined. If data is available,
+ * there will be two records: one for core, and another for all of contrib
+ * (assuming there are any contributed modules or themes enabled on the site).
+ * In addition to the fields expected by hook_requirements ('value', 'severity',
+ * and optionally 'description'), this array will contain a 'reason' attribute,
+ * which is an integer constant to indicate why the given status is being
+ * returned (UPDATE_NOT_SECURE, UPDATE_NOT_CURRENT, or UPDATE_UNKNOWN). This is
+ * used for generating the appropriate email notification messages during
+ * update_cron(), and might be useful for other modules that invoke
+ * update_requirements() to find out if the site is up to date or not.
  *
  * @see _update_message_text()
  * @see _update_cron_notify()
@@ -83,20 +82,20 @@ function update_uninstall() {
  * This is shared for both core and contrib to generate the right elements in
  * the array for hook_requirements().
  *
- * @param $project
+ * @param array $project
  *   Array of information about the project we're testing as returned by
  *   update_calculate_project_data().
- * @param $type
+ * @param string $type
  *   What kind of project this is ('core' or 'contrib').
  *
- * @return
+ * @return array
  *   An array to be included in the nested $requirements array.
  *
  * @see hook_requirements()
  * @see update_requirements()
  * @see update_calculate_project_data()
  */
-function _update_requirement_check($project, $type) {
+function _update_requirement_check(array $project, $type) {
   $requirement = array();
   if ($type == 'core') {
     $requirement['title'] = t('Drupal core update status');
diff --git a/core/modules/update/update.manager.inc b/core/modules/update/update.manager.inc
index 41866c7..3572f86 100644
--- a/core/modules/update/update.manager.inc
+++ b/core/modules/update/update.manager.inc
@@ -41,12 +41,12 @@
 /**
  * Batch callback: Performs actions when the download batch is completed.
  *
- * @param $success
+ * @param bool $success
  *   TRUE if the batch operation was successful, FALSE if there were errors.
- * @param $results
+ * @param array $results
  *   An associative array of results from the batch operation.
  */
-function update_manager_download_batch_finished($success, $results) {
+function update_manager_download_batch_finished($success, array $results) {
   if (!empty($results['errors'])) {
     $item_list = array(
       '#theme' => 'item_list',
@@ -76,12 +76,12 @@ function update_manager_download_batch_finished($success, $results) {
  *   The update manager operation we're in the middle of. Can be either 'update'
  *   or 'install'. Use to provide operation-specific interface text.
  *
- * @return
+ * @return bool
  *   TRUE if the update manager should continue to the next step in the
  *   workflow, or FALSE if we've hit a fatal configuration and must halt the
  *   workflow.
  */
-function _update_manager_check_backends(&$form, $operation) {
+function _update_manager_check_backends(array &$form, $operation) {
   // If file transfers will be performed locally, we do not need to display any
   // warnings or notices to the user and should automatically continue the
   // workflow, since we won't be using a FileTransfer backend that requires
@@ -146,6 +146,7 @@ function _update_manager_check_backends(&$form, $operation) {
  *   The Archiver object used to extract the archive.
  *
  * @throws Exception
+ *   Was unable to extract the archive.
  */
 function update_manager_archive_extract($file, $directory) {
   $archiver = archiver_get_archiver($file);
@@ -197,7 +198,7 @@ function update_manager_archive_verify($project, $archive_file, $directory) {
  *
  * Returns the local path if the file has already been downloaded.
  *
- * @param $url
+ * @param string $url
  *   The URL of the file on the server.
  *
  * @return string
@@ -239,7 +240,7 @@ function update_manager_file_get($url) {
  *
  * @see update_manager_download_page()
  */
-function update_manager_batch_project_get($project, $url, &$context) {
+function update_manager_batch_project_get($project, $url, array &$context) {
   // This is here to show the user that we are in the process of downloading.
   if (!isset($context['sandbox']['started'])) {
     $context['sandbox']['started'] = TRUE;
@@ -294,7 +295,7 @@ function update_manager_batch_project_get($project, $url, &$context) {
  * it. However, it is supported here because it is a common configuration on
  * shared hosting, and there is nothing Drupal can do to prevent it.
  *
- * @return
+ * @return bool
  *   TRUE if local file transfers are allowed on this server, or FALSE if not.
  *
  * @see install_check_requirements()
diff --git a/core/modules/update/update.module b/core/modules/update/update.module
index 0619dbb..60c7a6f 100644
--- a/core/modules/update/update.module
+++ b/core/modules/update/update.module
@@ -16,7 +16,6 @@
 use Drupal\Core\Form\FormStateInterface;
 use Drupal\Core\Routing\RouteMatchInterface;
 use Drupal\Core\Site\Settings;
-use Symfony\Cmf\Component\Routing\RouteObjectInterface;
 
 // These are internally used constants for this code, do not modify.
 
@@ -257,7 +256,8 @@ function update_themes_installed($themes) {
 /**
  * Implements hook_themes_uninstalled().
  *
- * If themes are uninstalled, we invalidate the information of available updates.
+ * If themes are uninstalled, we invalidate the information of available
+ * updates.
  */
 function update_themes_uninstalled($themes) {
   // Clear all update module data.
@@ -381,7 +381,7 @@ function update_get_available($refresh = FALSE) {
  *
  * @see \Drupal\update\UpdateFetcher::createFetchTask()
  */
-function update_create_fetch_task($project) {
+function update_create_fetch_task(array $project) {
   \Drupal::service('update.processor')->createFetchTask($project);
 }
 
@@ -408,14 +408,14 @@ function update_fetch_data() {
 /**
  * Batch callback: Performs actions when all fetch tasks have been completed.
  *
- * @param $success
+ * @param bool $success
  *   TRUE if the batch operation was successful; FALSE if there were errors.
- * @param $results
+ * @param array $results
  *   An associative array of results from the batch operation, including the key
  *   'updated' which holds the total number of projects we fetched available
  *   update data for.
  */
-function update_fetch_data_finished($success, $results) {
+function update_fetch_data_finished($success, array $results) {
   if ($success) {
     if (!empty($results)) {
       if (!empty($results['updated'])) {
@@ -450,7 +450,7 @@ function update_fetch_data_finished($success, $results) {
  * @see _update_cron_notify()
  * @see _update_message_text()
  */
-function update_mail($key, &$message, $params) {
+function update_mail($key, array &$message, array $params) {
   $langcode = $message['langcode'];
   $language = \Drupal::languageManager()->getLanguage($langcode);
   $message['subject'] .= t('New release(s) available for !site_name', array('!site_name' => \Drupal::config('system.site')->get('name')), array('langcode' => $langcode));
@@ -574,10 +574,11 @@ function _update_message_text($msg_type, $msg_reason, $report_link = FALSE, $lan
  *   for the keys used.
  *
  * @return int
+ *   Callback return value for uasort().
  *
  * @see update_requirements()
  */
-function _update_project_status_sort($a, $b) {
+function _update_project_status_sort(array $a, array $b) {
   // The status constants are numerically in the right order, so we can
   // usually subtract the two to compare in the order we want. However,
   // negative status values should be treated as if they are huge, since we
@@ -600,12 +601,9 @@ function _update_project_status_sort($a, $b) {
  *   An associative array containing:
  *   - last: The timestamp when the site last checked for available updates.
  *
- * @return string
- *   Rendered HTML for the last time we checked for update data.
- *
  * @see theme_update_report()
  */
-function template_preprocess_update_last_check(&$variables) {
+function template_preprocess_update_last_check(array &$variables) {
   $variables['time'] = \Drupal::service('date.formatter')->formatInterval(REQUEST_TIME - $variables['last']);
   $variables['link'] = \Drupal::l(t('Check manually'), new Url('update.manual_status', array(), array('query' => drupal_get_destination())));
 }
diff --git a/core/modules/update/update.report.inc b/core/modules/update/update.report.inc
index 61146b4..ef49122 100644
--- a/core/modules/update/update.report.inc
+++ b/core/modules/update/update.report.inc
@@ -20,7 +20,7 @@
  *
  * @ingroup themeable
  */
-function template_preprocess_update_report(&$variables) {
+function template_preprocess_update_report(array &$variables) {
   $data = $variables['data'];
 
   $last = \Drupal::state()->get('update.last_check') ?: 0;
@@ -130,7 +130,7 @@ function template_preprocess_update_report(&$variables) {
  *
  * @ingroup themeable
  */
-function template_preprocess_update_project_status(&$variables) {
+function template_preprocess_update_project_status(array &$variables) {
   // Storing by reference because we are sorting the project values.
   $project = &$variables['project'];
   $includes_status = $variables['includes_status'];