diff --git a/core/core.services.yml b/core/core.services.yml
index d1a0e6c..8fb7a70 100644
--- a/core/core.services.yml
+++ b/core/core.services.yml
@@ -472,7 +472,10 @@ services:
     lazy: true
   module_listing:
     class: Drupal\Core\Extension\ModuleExtensionList
-    arguments: ['@app.root', 'module', '@cache.default', '@info_parser', '@module_handler', '@config.factory']
+    arguments: ['@app.root', 'module', '@cache.default', '@info_parser', '@module_handler', '@state', '@config.factory', '@profile_listing']
+  profile_listing:
+    class: Drupal\Core\Extension\ProfileExtensionList
+    arguments: ['@app.root', 'profile', '@cache.default', '@info_parser', '@module_handler', '@state']
   content_uninstall_validator:
     class: Drupal\Core\Entity\ContentUninstallValidator
     tags:
diff --git a/core/includes/bootstrap.inc b/core/includes/bootstrap.inc
index 5eeaf3c..3f59276 100644
--- a/core/includes/bootstrap.inc
+++ b/core/includes/bootstrap.inc
@@ -198,11 +198,17 @@ function drupal_get_filename($type, $name, $filename = NULL) {
     return 'core/core.info.yml';
   }
 
-  // Profiles are converted into modules in system_rebuild_module_data().
-  // @todo Remove false-exposure of profiles as modules.
-  if ($type == 'profile') {
-    $type = 'module';
+  if ($type === 'module' || $type === 'profile') {
+    $service = $type . '_listing';
+    if (isset($filename)) {
+      // Manually add the info file path of an extension.
+      return \Drupal::service($service)->setFilename($name);
+    }
+    else {
+      return \Drupal::service($service)->getFilename($name);
+    }
   }
+
   if (!isset($files[$type])) {
     $files[$type] = array();
   }
@@ -211,15 +217,6 @@ function drupal_get_filename($type, $name, $filename = NULL) {
     $files[$type][$name] = $filename;
   }
   elseif (!isset($files[$type][$name])) {
-    // If the pathname of the requested extension is not known, try to retrieve
-    // the list of extension pathnames from various providers, checking faster
-    // providers first.
-    // Retrieve the current module list (derived from the service container).
-    if ($type == 'module' && \Drupal::hasService('module_handler')) {
-      foreach (\Drupal::moduleHandler()->getModuleList() as $module_name => $module) {
-        $files[$type][$module_name] = $module->getPathname();
-      }
-    }
     // If still unknown, retrieve the file list prepared in state by
     // system_rebuild_module_data() and
     // \Drupal\Core\Extension\ThemeHandlerInterface::rebuildThemeData().
@@ -251,9 +248,6 @@ function drupal_get_filename($type, $name, $filename = NULL) {
  *   The path to the requested item or an empty string if the item is not found.
  */
 function drupal_get_path($type, $name) {
-  if ($type === 'module' || $type === 'profile') {
-    return dirname(\Drupal::service('module_listing')->getFilenames()[$name]);
-  }
   return dirname(drupal_get_filename($type, $name));
 }
 
diff --git a/core/includes/module.inc b/core/includes/module.inc
index 027b236..cd2575c 100644
--- a/core/includes/module.inc
+++ b/core/includes/module.inc
@@ -57,7 +57,6 @@ function system_list($type) {
  */
 function system_list_reset() {
   drupal_static_reset('system_list');
-  drupal_static_reset('system_rebuild_module_data');
   \Drupal::service('module_listing')->reset();
   \Drupal::cache('bootstrap')->delete('system_list');
 }
diff --git a/core/lib/Drupal/Core/Extension/ExtensionList.php b/core/lib/Drupal/Core/Extension/ExtensionList.php
index 3e98d84..a0f9a7e 100644
--- a/core/lib/Drupal/Core/Extension/ExtensionList.php
+++ b/core/lib/Drupal/Core/Extension/ExtensionList.php
@@ -7,8 +7,9 @@
 
 namespace Drupal\Core\Extension;
 
-use Drupal\Component\Utility\SafeMarkup;
+use Drupal\Component\Render\FormattableMarkup;
 use Drupal\Core\Cache\CacheBackendInterface;
+use Drupal\Core\State\StateInterface;
 
 /**
  * Provides available extensions.
@@ -37,6 +38,11 @@
   protected $cache;
 
   /**
+   * The state service.
+   */
+  protected $state;
+
+  /**
    * Default information added to every extension.
    *
    * @var array
@@ -74,11 +80,28 @@
   /**
    * A list of extension folder names keyed by extension name.
    *
-   * @var string
+   * @var string[]
    */
   protected $fileNames;
 
   /**
+   * A list of extension folder names directly added in code (not discovered).
+   *
+   * It is important to keep a separate list to ensure that it takes priority
+   * over the discovered extension folder.
+   *
+   * @var string[]
+   */
+  protected $addedFileNames;
+
+  /**
+   * The extension discovery service.
+   *
+   * @var \Drupal\Core\Extension\ExtensionDiscovery
+   */
+  protected $extensionDiscovery;
+
+  /**
    * Constructs a new ExtensionList instance.
    *
    * @param string $root
@@ -91,25 +114,30 @@
    *   The info parser.
    * @param \Drupal\Core\Extension\ModuleHandlerInterface $module_handler
    *   The module handler.
+   * @param \Drupal\Core\State\StateInterface $state
+   *   The state service.
    */
-  public function __construct($root, $type, CacheBackendInterface $cache, InfoParserInterface $info_parser, ModuleHandlerInterface $module_handler) {
+  public function __construct($root, $type, CacheBackendInterface $cache, InfoParserInterface $info_parser, ModuleHandlerInterface $module_handler, StateInterface $state) {
     $this->root = $root;
     $this->type = $type;
     $this->cache = $cache;
+    $this->state = $state;
     $this->infoParser = $info_parser;
     $this->moduleHandler = $module_handler;
+    $this->extensionDiscovery = new ExtensionDiscovery($root);
   }
 
   /**
    * Resets the stored extension list.
    */
   public function reset() {
-    $this->extensions = NULL;
+    $this->addedFileNames = NULL;
     $this->cache->delete($this->getCacheId());
     $this->extensionInfo = NULL;
     $this->cache->delete("system.{$this->type}.info");
     $this->fileNames = NULL;
-    \Drupal::state()->delete("system.{$this->type}.files");
+    $this->state->delete("system.{$this->type}.files");
+    $this->extensions = NULL;
     return $this;
   }
 
@@ -125,18 +153,21 @@ protected function getCacheId() {
   /**
    * Returns the human readable name of the extension.
    *
-   * @param string $name
+   * @param string $machine_name
    *   The extension name.
    *
    * @return string
    *   The human readable name of the extension.
+   *
+   * @throws \InvalidArgumentException
+   *   If there is no extension with the supplied machine name.
    */
-  public function getName($name) {
+  public function getName($machine_name) {
     $extensions = $this->listExtensions();
-    if (isset($extensions[$name])) {
-      return $extensions[$name]->info['name'];
+    if (isset($extensions[$machine_name])) {
+      return $extensions[$machine_name]->info['name'];
     }
-    throw new \InvalidArgumentException(SafeMarkup::format('The @type %name does not exist.', ['@type' => $this->type, '%name' => $name]));
+    throw new \InvalidArgumentException(new FormattableMarkup('The @type %name does not exist.', ['@type' => $this->type, '%name' => $machine_name]));
   }
 
   /**
@@ -146,6 +177,9 @@ public function getName($name) {
    *   The extension name.
    *
    * @return \Drupal\Core\Extension\Extension
+   *
+   * @throws \InvalidArgumentException
+   *   If there is no extension with the supplied name.
    */
   public function getExtension($name) {
     $extensions = $this->listExtensions();
@@ -153,7 +187,7 @@ public function getExtension($name) {
       return $extensions[$name];
     }
 
-    throw new \InvalidArgumentException(SafeMarkup::format('The @type %name does not exist.', ['@type' => $this->type, '%name' => $name]));
+    throw new \InvalidArgumentException(new FormattableMarkup('The @type %name does not exist.', ['@type' => $this->type, '%name' => $name]));
   }
 
   /**
@@ -181,13 +215,10 @@ public function listExtensions() {
    * Overriding this method gives other code the chance to add additional
    * extensions to this raw listing.
    *
-   * @param \Drupal\Core\Extension\ExtensionDiscovery $discovery
-   *   The extension discovery.
-   *
    * @return \Drupal\Core\Extension\Extension[]
    */
-  protected function doScanExtensions(ExtensionDiscovery $discovery) {
-    return $discovery->scan($this->type);
+  protected function doScanExtensions() {
+    return $this->extensionDiscovery->scan($this->type);
   }
 
   /**
@@ -196,10 +227,8 @@ protected function doScanExtensions(ExtensionDiscovery $discovery) {
    * @return \Drupal\Core\Extension\Extension[]
    */
   protected function doListExtensions() {
-    $listing = new ExtensionDiscovery($this->root);
-
     // Find extensions.
-    $extensions = $this->doScanExtensions($listing);
+    $extensions = $this->doScanExtensions();
 
     // Read info files for each extension.
     foreach ($extensions as $name => $extension) {
@@ -215,7 +244,6 @@ protected function doListExtensions() {
 
       // Invoke hook_system_info_alter() to give installed modules a chance to
       // modify the data in the .info.yml files if necessary.
-      // @todo Remove $type argument, obsolete with $module->getType().
       $this->moduleHandler->alter('system_info', $extensions[$name]->info, $extensions[$name], $this->type);
     }
 
@@ -223,23 +251,36 @@ protected function doListExtensions() {
   }
 
   /**
+   * Returns information about a specified module or theme.
+   *
+   * This function returns the contents of the .info.yml file for the specified
+   * installed module or theme.
+   *
+   * @param string $name
+   *   The name of a module or theme whose information shall be returned. If
+   *   $name does not exist or is not enabled, an empty array will be returned.
+   *
+   * @return array|null
+   *   An associative array of module or theme information. NULL if the module
+   *   is disabled or does not exist.
+   */
+  public function getInfo($name) {
+    // Ensure that $this->extensionInfo is primed.
+    $this->getAllInfo();
+    return isset($this->extensionInfo[$name]) ? $this->extensionInfo[$name] : NULL;
+  }
+
+  /**
    * Returns an array of information about enabled modules or themes.
    *
    * This function returns the contents of the .info.yml file for each installed
    * module or theme.
    *
-   * @param string $name
-   *   (optional) The name of a module or theme whose information shall be
-   *   returned. If omitted, all records for the provided $type will be returned.
-   *   If $name does not exist in the provided $type or is not enabled, an empty
-   *   array will be returned.
-   *
    * @return array
-   *   An associative array of module or theme information keyed by name, or only
-   *   information for $name, if given. If no records are available, an empty
-   *   array is returned.
+   *   An associative array of module or theme information keyed by name. If no
+   *   records are available, an empty array is returned.
    */
-  public function getInfo($name = NULL) {
+  public function getAllInfo() {
     if (!isset($this->extensionInfo)) {
       if ($cache = $this->cache->get("system.{$this->type}.info")) {
         $info = $cache->data;
@@ -249,33 +290,36 @@ public function getInfo($name = NULL) {
       }
       $this->extensionInfo = $info;
     }
-    if (isset($name)) {
-      return isset($this->extensionInfo[$name]) ? $this->extensionInfo[$name] : [];
-    }
     return $this->extensionInfo;
   }
 
+  /**
+   * Generates the information from .info.yml files for extensions of this type.
+   *
+   * The information is placed in cache with the "system.{extension_type}.info"
+   * key.
+   *
+   * @return array
+   *   An array of arrays of .info.yml entries keyed by the extension name.
+   */
   protected function recalculateInfo() {
     $info = [];
     foreach ($this->listExtensions() as $name => $extension) {
       $info[$name] = $extension->info;
     }
-    // Store the module information in cache. This cache is cleared by
-    // calling system_rebuild_module_data(), for example, when listing
-    // modules, (un)installing modules, importing configuration, updating
-    // the site and when flushing all the caches.
+    // Store the module information in cache.
     $this->cache->set("system.{$this->type}.info", $info);
     return $info;
   }
 
   /**
-   * Return a list of extension folder names keyed by extension name.
+   * Returns a list of extension folder names keyed by extension name.
    *
    * @return string[]
    */
   public function getFilenames() {
     if (!isset($this->fileNames)) {
-      $file_names = \Drupal::state()->get("system.{$this->type}.files");
+      $file_names = $this->state->get("system.{$this->type}.files");
       if (!isset($file_names)) {
         $file_names = $this->recalculateFilenames();
       }
@@ -284,6 +328,15 @@ public function getFilenames() {
     return $this->fileNames;
   }
 
+  /**
+   * Generates a sorted list of .info.yml file locations for all extensions.
+   *
+   * The information is placed in state with the "system.{extension_type}.files"
+   * key.
+   *
+   * @return array
+   *   An array of .info.yml file locations keyed by the extension name.
+   */
   protected function recalculateFilenames() {
     $file_names = [];
     $extensions = $this->listExtensions();
@@ -291,8 +344,78 @@ protected function recalculateFilenames() {
     foreach ($extensions as $name => $extension) {
       $file_names[$name] = $extension->getPathname();
     }
-//    \Drupal::state()->set("system.{$this->type}.files", $file_names);
+    $this->state->set("system.{$this->type}.files", $file_names);
     return $file_names;
   }
 
+  /**
+   * Sets the filename for an extension.
+   *
+   * @param string $extension_name
+   *   The name of the extension for which the filename is requested.
+   * @param string $filename
+   *   The filename of the item which is to be set explicitly rather
+   *   than by consulting the dynamic modules listing.
+   */
+  public function setFilename($extension_name, $filename) {
+    $this->addedFileNames[$extension_name] = $filename;
+  }
+
+  /**
+   * Gets the filename for a system resource.
+   *
+   * The filename, whether provided, cached, or retrieved from the database, is
+   * only returned if the file exists.
+   *
+   * This function plays a key role in allowing Drupal's resources (modules
+   * and themes) to be located in different places depending on a site's
+   * configuration. For example, a module 'foo' may legally be located
+   * in any of these three places:
+   *
+   * core/modules/foo/foo.info.yml
+   * modules/foo/foo.info.yml
+   * sites/example.com/modules/foo/foo.info.yml
+   * core/themes/foo/foo.info.yml
+   * themes/foo/foo.info.yml
+   *
+   * Calling ExtensionList::getFilename('foo') will give you one of the above,
+   * depending on where the extension is located and what type it is.
+   *
+   * @param string $extension_name
+   *   The name of the item for which the filename is requested. Ignored for
+   *   $type 'core'.
+   *
+   * @return string
+   *   The filename of the requested item if it is found. An error is triggered
+   *   if it is not.
+   */
+  public function getFilename($extension_name) {
+    // Ensure that $this->fileNames is primed.
+    $this->getFilenames();
+    if (isset($this->addedFileNames[$extension_name])) {
+      return $this->addedFileNames[$extension_name];
+    }
+    else if (isset($this->fileNames[$extension_name])) {
+      return $this->fileNames[$extension_name];
+    }
+    else {
+      trigger_error(new FormattableMarkup('The following @type is missing from the file system: @name', array('@type' => $this->type, '@name' => $extension_name)), E_USER_WARNING);
+    }
+  }
+
+
+  /**
+   * Gets the path to an extension of a specific type (module, theme, etc.).
+   *
+   * @param string $extension_name
+   *   The name of the extension for which the path is requested.
+   *
+   * @return string
+   *   The drupal root-relative path to the specified extension. An error is
+   *   triggered if the extension is not found.
+   */
+  public function getPath($extension_name) {
+    return dirname($this->getFilename($extension_name));
+  }
+
 }
diff --git a/core/lib/Drupal/Core/Extension/ModuleExtensionList.php b/core/lib/Drupal/Core/Extension/ModuleExtensionList.php
index 9e7763e..e925aac 100644
--- a/core/lib/Drupal/Core/Extension/ModuleExtensionList.php
+++ b/core/lib/Drupal/Core/Extension/ModuleExtensionList.php
@@ -9,6 +9,7 @@
 
 use Drupal\Core\Cache\CacheBackendInterface;
 use Drupal\Core\Config\ConfigFactoryInterface;
+use Drupal\Core\State\StateInterface;
 use Drupal\Core\StringTranslation\StringTranslationTrait;
 
 /**
@@ -37,6 +38,13 @@ class ModuleExtensionList extends ExtensionList {
   protected $configFactory;
 
   /**
+   * The profile list needed by this module list.
+   *
+   * @var \Drupal\Core\Extension\ExtensionList
+   */
+  protected $profileList;
+
+  /**
    * Constructs a new ModuleExtensionList instance.
    *
    * @param string $root
@@ -49,23 +57,28 @@ class ModuleExtensionList extends ExtensionList {
    *   The info parser.
    * @param \Drupal\Core\Extension\ModuleHandlerInterface $module_handler
    *   The module handler.
+   * @param \Drupal\Core\State\StateInterface $state
+   *   The state service.
    * @param \Drupal\Core\Config\ConfigFactoryInterface $config_factory
    *   The config factory.
+   * @param \Drupal\Core\Extension\ExtensionList $profile_list
+   *   The site profile listing.
    */
-  public function __construct($root, $type, CacheBackendInterface $cache, InfoParserInterface $info_parser, ModuleHandlerInterface $module_handler, ConfigFactoryInterface $config_factory) {
-    parent::__construct($root, $type, $cache, $info_parser, $module_handler);
+  public function __construct($root, $type, CacheBackendInterface $cache, InfoParserInterface $info_parser, ModuleHandlerInterface $module_handler, StateInterface $state, ConfigFactoryInterface $config_factory, ExtensionList $profile_list) {
+    parent::__construct($root, $type, $cache, $info_parser, $module_handler, $state);
 
     $this->configFactory = $config_factory;
+    $this->profileList = $profile_list;
   }
 
   /**
    * {@inheritdoc}
    */
-  protected function doScanExtensions(ExtensionDiscovery $discovery) {
-    $extensions = parent::doScanExtensions($discovery);
+  protected function doScanExtensions() {
+    $extensions = parent::doScanExtensions();
 
     // Find installation profiles.
-    $profiles = $discovery->scan('profile');
+    $profiles = $this->profileList->listExtensions();
 
     // Include the installation profile in modules that are loaded.
     if ($profile = drupal_get_profile()) {
@@ -81,19 +94,16 @@ protected function doScanExtensions(ExtensionDiscovery $discovery) {
    * {@inheritdoc}
    */
   protected function doListExtensions() {
-    $listing = new ExtensionDiscovery($this->root);
-
     // Find installation profiles. This needs to happen before performing a
-    // module scan as the module scan requires knowing what the active profile is.
-    // @todo Remove as part of https://www.drupal.org/node/2186491
-    $profiles = $listing->scan('profile');
+    // module scan as the module scan needs to know what the active profile is.
+    $profiles = $this->profileList->listExtensions();
     $profile = drupal_get_profile();
     if ($profile && isset($profiles[$profile])) {
-      // Prime the drupal_get_filename() static cache with the profile info file
-      // location so we can use drupal_get_path() on the active profile during
-      // the module scan.
-      // @todo Remove as part of https://www.drupal.org/node/2186491
-      drupal_get_filename('profile', $profile, $profiles[$profile]->getPathname());
+      // Set the profile in the ExtensionDiscovery so we can scan from the right
+      // profile directory.
+      $this->extensionDiscovery->setProfileDirectories([
+        $profile => $profiles[$profile]->getPathname(),
+      ]);
     }
 
     // Find modules.
@@ -101,7 +111,7 @@ protected function doListExtensions() {
     // It is possible that a module was marked as required by
     // hook_system_info_alter() and modules that it depends on are not required.
     foreach ($extensions as $extension) {
-      $this->moduleDataEnsureRequired($extension, $extensions);
+      $this->ensureRequiredDependencies($extension, $extensions);
     }
 
     if ($profile) {
@@ -143,7 +153,7 @@ protected function doListExtensions() {
    * @param \Drupal\Core\Extension\Extension[] $modules
    *   The array of all module info.
    */
-  protected function moduleDataEnsureRequired(Extension $module, array $modules = []) {
+  protected function ensureRequiredDependencies(Extension $module, array $modules = []) {
     if (!empty($module->info['required'])) {
       foreach ($module->info['dependencies'] as $dependency) {
         $dependency_name = ModuleHandler::parseDependency($dependency)['name'];
@@ -151,7 +161,7 @@ protected function moduleDataEnsureRequired(Extension $module, array $modules =
           $modules[$dependency_name]->info['required'] = TRUE;
           $modules[$dependency_name]->info['explanation'] = $this->t('Dependency of required module @module', array('@module' => $module->info['name']));
           // Ensure any dependencies it has are required.
-         $this->moduleDataEnsureRequired($modules[$dependency_name], $modules);
+         $this->ensureRequiredDependencies($modules[$dependency_name], $modules);
         }
       }
     }
diff --git a/core/lib/Drupal/Core/Extension/ModuleInstaller.php b/core/lib/Drupal/Core/Extension/ModuleInstaller.php
index 9c652ba..36e8ed8 100644
--- a/core/lib/Drupal/Core/Extension/ModuleInstaller.php
+++ b/core/lib/Drupal/Core/Extension/ModuleInstaller.php
@@ -190,7 +190,7 @@ public function install(array $module_list, $enable_dependencies = TRUE) {
         // Clear the static cache of system_rebuild_module_data() to pick up the
         // new module, since it merges the installation status of modules into
         // its statically cached list.
-        drupal_static_reset('system_rebuild_module_data');
+        \Drupal::service('module_listing')->reset();
 
         // Update the kernel to include it.
         $this->updateKernel($module_filenames);
@@ -426,10 +426,10 @@ public function uninstall(array $module_list, $uninstall_dependents = TRUE) {
       // Remove any potential cache bins provided by the module.
       $this->removeCacheBins($module);
 
-      // Clear the static cache of system_rebuild_module_data() to pick up the
+      // Clear the static cache of ModuleExtensionList to pick up the
       // new module, since it merges the installation status of modules into
       // its statically cached list.
-      drupal_static_reset('system_rebuild_module_data');
+      \Drupal::service('module_listing')->reset();
 
       // Clear plugin manager caches.
       \Drupal::getContainer()->get('plugin.cache_clearer')->clearCachedDefinitions();
diff --git a/core/lib/Drupal/Core/Extension/ProfileExtensionList.php b/core/lib/Drupal/Core/Extension/ProfileExtensionList.php
new file mode 100644
index 0000000..8bae168
--- /dev/null
+++ b/core/lib/Drupal/Core/Extension/ProfileExtensionList.php
@@ -0,0 +1,18 @@
+<?php
+
+namespace Drupal\Core\Extension;
+
+class ProfileExtensionList extends ExtensionList {
+
+  /**
+   * {@inheritdoc}
+   */
+  protected $defaults = [
+    'dependencies' => [],
+    'description' => '',
+    'package' => 'Other',
+    'version' => NULL,
+    'php' => DRUPAL_MINIMUM_PHP,
+  ];
+
+}
diff --git a/core/modules/book/src/Tests/BookUninstallTest.php b/core/modules/book/src/Tests/BookUninstallTest.php
index b46901e..45dac11 100644
--- a/core/modules/book/src/Tests/BookUninstallTest.php
+++ b/core/modules/book/src/Tests/BookUninstallTest.php
@@ -81,11 +81,7 @@ public function testBookUninstall() {
 
     $book_node->delete();
     // No nodes exist therefore the book module is not required.
-    $module_data = _system_rebuild_module_data();
-    /** @var \Drupal\Core\Extension\ModuleExtensionList $module_listing */
-    $module_listing = \Drupal::service('module_listing');
-    $module_listing->reset();
-    $module_data = $module_listing->listExtensions();
+    $module_data = \Drupal::service('module_listing')->reset()->listExtensions();
     $this->assertFalse(isset($module_data['book']->info['required']), 'The book module is not required.');
 
     $node = Node::create(array('title' => $this->randomString(), 'type' => $content_type->id()));
diff --git a/core/modules/system/src/Tests/Bootstrap/GetFilenameUnitTest.php b/core/modules/system/src/Tests/Bootstrap/GetFilenameUnitTest.php
index 27ca162..dc6763a 100644
--- a/core/modules/system/src/Tests/Bootstrap/GetFilenameUnitTest.php
+++ b/core/modules/system/src/Tests/Bootstrap/GetFilenameUnitTest.php
@@ -26,8 +26,6 @@ function testDrupalGetFilename() {
     $install_state['parameters']['profile'] = 'testing';
 
     // Rebuild system.module.files state data.
-    // @todo Remove as part of https://www.drupal.org/node/2186491
-    drupal_static_reset('system_rebuild_module_data');
     system_rebuild_module_data();
 
     // Retrieving the location of a module.
diff --git a/core/modules/system/system.module b/core/modules/system/system.module
index e7c61ab..9e541c4 100644
--- a/core/modules/system/system.module
+++ b/core/modules/system/system.module
@@ -888,9 +888,7 @@ function system_check_directory($form_element, FormStateInterface $form_state) {
  */
 function system_get_info($type, $name = NULL) {
   if ($type == 'module') {
-    /** @var \Drupal\Core\Extension\ModuleExtensionList $module_listing */
-    $module_listing = \Drupal::service('module_listing');
-    return $module_listing->getInfo($name);
+    return \Drupal::service('module_listing')->getInfo($name);
   }
   else {
     // @todo
@@ -915,8 +913,7 @@ function system_get_info($type, $name = NULL) {
  *   An associative array of module information.
  */
 function _system_rebuild_module_data() {
-  \Drupal::service('module_listing')->reset();
-  return \Drupal::service('module_listing')->listExtensions();
+  return \Drupal::service('module_listing')->reset()->listExtensions();
 }
 
 /**
@@ -926,9 +923,7 @@ function _system_rebuild_module_data() {
  *   Array of all available modules and their data.
  */
 function system_rebuild_module_data() {
-  \Drupal::service('module_listing')->reset();
-  $modules_cache = \Drupal::service('module_listing')->listExtensions();
-  return $modules_cache;
+  return \Drupal::service('module_listing')->reset()->listExtensions();
 }
 
 /**
diff --git a/core/modules/system/tests/src/Kernel/Extension/ModuleHandlerTest.php b/core/modules/system/tests/src/Kernel/Extension/ModuleHandlerTest.php
index 1dd99cd..413f912 100644
--- a/core/modules/system/tests/src/Kernel/Extension/ModuleHandlerTest.php
+++ b/core/modules/system/tests/src/Kernel/Extension/ModuleHandlerTest.php
@@ -119,7 +119,6 @@ function testDependencyResolution() {
     // Color will depend on Config, which depends on a non-existing module Foo.
     // Nothing should be installed.
     \Drupal::state()->set('module_test.dependency', 'missing dependency');
-    drupal_static_reset('system_rebuild_module_data');
     \Drupal::service('module_listing')->reset();
 
     try {
@@ -135,7 +134,6 @@ function testDependencyResolution() {
     // Fix the missing dependency.
     // Color module depends on Config. Config depends on Help module.
     \Drupal::state()->set('module_test.dependency', 'dependency');
-    drupal_static_reset('system_rebuild_module_data');
     \Drupal::service('module_listing')->reset();
 
     $result = $this->moduleInstaller()->install(array('color'));
@@ -168,7 +166,6 @@ function testDependencyResolution() {
     // dependency on a specific version of Help module in its info file. Make
     // sure that Drupal\Core\Extension\ModuleHandler::install() still works.
     \Drupal::state()->set('module_test.dependency', 'version dependency');
-    drupal_static_reset('system_rebuild_module_data');
     \Drupal::service('module_listing')->reset();
 
     $result = $this->moduleInstaller()->install(array('color'));
@@ -199,8 +196,7 @@ function testUninstallProfileDependency() {
     drupal_get_filename('profile', $profile, 'core/profiles/' . $profile . '/' . $profile . '.info.yml');
     $this->enableModules(array('module_test', $profile));
 
-    drupal_static_reset('system_rebuild_module_data');
-    $data = system_rebuild_module_data();
+    $data = \Drupal::service('module_listing')->reset()->listExtensions();
     $this->assertTrue(isset($data[$profile]->requires[$dependency]));
 
     $this->moduleInstaller()->install(array($dependency));
@@ -238,7 +234,7 @@ function testUninstallContentDependency() {
     // entity_test will depend on help. This way help can not be uninstalled
     // when there is test content preventing entity_test from being uninstalled.
     \Drupal::state()->set('module_test.dependency', 'dependency');
-    drupal_static_reset('system_rebuild_module_data');
+    \Drupal::service('module_listing')->reset();
 
     // Create an entity so that the modules can not be disabled.
     $entity = entity_create('entity_test', array('name' => $this->randomString()));