diff --git a/core/authorize.php b/core/authorize.php
index d812f2e..2587c46 100644
--- a/core/authorize.php
+++ b/core/authorize.php
@@ -65,9 +65,8 @@ function authorize_access_allowed() {
 
 // We have to enable the user and system modules, even to check access and
 // display errors via the maintenance theme.
-$module_list['system'] = 'core/modules/system/system.module';
-$module_list['user'] = 'core/modules/user/user.module';
-\Drupal::moduleHandler()->setModuleList($module_list);
+\Drupal::moduleHandler()->add('system', 'core/modules/system');
+\Drupal::moduleHandler()->add('user', 'core/modules/user');
 \Drupal::moduleHandler()->load('system');
 \Drupal::moduleHandler()->load('user');
 
diff --git a/core/includes/bootstrap.inc b/core/includes/bootstrap.inc
index 222ac0c..33ee8f1 100644
--- a/core/includes/bootstrap.inc
+++ b/core/includes/bootstrap.inc
@@ -628,9 +628,9 @@ function _drupal_request_initialize() {
  * configuration. For example, a module 'foo' may legally be located
  * in any of these three places:
  *
- * core/modules/foo/foo.module
- * modules/foo/foo.module
- * sites/example.com/modules/foo/foo.module
+ * core/modules/foo/foo.info.yml
+ * modules/foo/foo.info.yml
+ * sites/example.com/modules/foo/foo.info.yml
  *
  * Calling drupal_get_filename('module', 'foo') will give you one of
  * the above, depending on where the module is located.
@@ -670,7 +670,9 @@ function drupal_get_filename($type, $name, $filename = NULL) {
     // providers first.
     // Retrieve the current module list (derived from the service container).
     if ($type == 'module' && \Drupal::hasService('module_handler')) {
-      $files[$type] += \Drupal::moduleHandler()->getModuleList();
+      foreach (\Drupal::moduleHandler()->getModuleList() as $module_name => $module) {
+        $files[$type][$module_name] = $module->getPathname();
+      }
     }
     // If still unknown, retrieve the file list prepared in state by
     // system_rebuild_module_data() and system_rebuild_theme_data().
@@ -685,7 +687,7 @@ function drupal_get_filename($type, $name, $filename = NULL) {
         $listing->setProfileDirectories(array());
       }
       foreach ($listing->scan($original_type) as $extension_name => $file) {
-        $files[$type][$extension_name] = $file->uri;
+        $files[$type][$extension_name] = $file->getPathname();
       }
     }
   }
diff --git a/core/includes/common.inc b/core/includes/common.inc
index 57095f7..578f584 100644
--- a/core/includes/common.inc
+++ b/core/includes/common.inc
@@ -4957,9 +4957,9 @@ function drupal_flush_all_caches() {
   // sufficient, since the list of enabled modules might have been adjusted
   // above due to changed code.
   $files = array();
-  foreach ($module_data as $module => $data) {
-    if (isset($data->uri) && $data->status) {
-      $files[$module] = $data->uri;
+  foreach ($module_data as $name => $extension) {
+    if ($extension->status) {
+      $files[$name] = $extension;
     }
   }
   \Drupal::service('kernel')->updateModules($module_handler->getModuleList(), $files);
diff --git a/core/includes/install.core.inc b/core/includes/install.core.inc
index f0e74e3..80349e3 100644
--- a/core/includes/install.core.inc
+++ b/core/includes/install.core.inc
@@ -492,7 +492,7 @@ function install_begin_request(&$install_state) {
   $module_handler = \Drupal::moduleHandler();
   if (!$module_handler->moduleExists('system')) {
     // Override the module list with a minimal set of modules.
-    $module_handler->setModuleList(array('system' => 'core/modules/system/system.module'));
+    $module_handler->add('system', 'core/modules/system');
   }
   // After setting up a custom and finite module list in a custom low-level
   // bootstrap like here, ensure to use ModuleHandler::loadAll() so that
@@ -507,7 +507,7 @@ function install_begin_request(&$install_state) {
 
   // Prime drupal_get_filename()'s static cache.
   foreach ($install_state['profiles'] as $name => $profile) {
-    drupal_get_filename('profile', $name, $profile->uri);
+    drupal_get_filename('profile', $name, $profile->getPathname());
   }
 
   // Prepare for themed output. We need to run this at the beginning of the
@@ -870,9 +870,7 @@ function install_tasks($install_state) {
   // Allow the installation profile to modify the full list of tasks.
   if (!empty($install_state['parameters']['profile'])) {
     $profile = $install_state['parameters']['profile'];
-    $profile_file = $install_state['profiles'][$profile]->uri;
-    if (file_exists($profile_file)) {
-      include_once DRUPAL_ROOT . '/' .  $profile_file;
+    if ($install_state['profiles'][$profile]->load()) {
       $function = $install_state['parameters']['profile'] . '_install_tasks_alter';
       if (function_exists($function)) {
         $function($tasks, $install_state);
@@ -1895,19 +1893,12 @@ function install_already_done_error() {
  *
  * @param $install_state
  *   An array of information about the current installation state. The loaded
- *   profile information will be added here, or an exception will be thrown if
- *   the profile cannot be loaded.
+ *   profile information will be added here.
  */
 function install_load_profile(&$install_state) {
   $profile = $install_state['parameters']['profile'];
-  $profile_file = $install_state['profiles'][$profile]->uri;
-  if (file_exists($profile_file)) {
-    include_once DRUPAL_ROOT . '/' . $profile_file;
-    $install_state['profile_info'] = install_profile_info($install_state['parameters']['profile'], $install_state['parameters']['langcode']);
-  }
-  else {
-    throw new Exception(t('Sorry, the profile you have chosen cannot be loaded.'));
-  }
+  $install_state['profiles'][$profile]->load();
+  $install_state['profile_info'] = install_profile_info($profile, $install_state['parameters']['langcode']);
 }
 
 /**
diff --git a/core/includes/install.inc b/core/includes/install.inc
index 3630e07..651228b 100644
--- a/core/includes/install.inc
+++ b/core/includes/install.inc
@@ -659,8 +659,9 @@ function drupal_install_system($install_state) {
     ->save();
 
   // Update the module list to include it. Reboot the kernel too.
-  \Drupal::moduleHandler()->setModuleList(array('system' => $system_path . '/system.module'));
-  $kernel->updateModules(array('system' => $system_path . '/system.module'));
+  \Drupal::moduleHandler()->add('system', 'core/modules/system');
+  $module_list = \Drupal::moduleHandler()->getModuleList();
+  $kernel->updateModules($module_list);
 
   \Drupal::service('config.installer')->installDefaultConfig('module', 'system');
 
diff --git a/core/includes/theme.maintenance.inc b/core/includes/theme.maintenance.inc
index 21c8d07..a0155e0 100644
--- a/core/includes/theme.maintenance.inc
+++ b/core/includes/theme.maintenance.inc
@@ -67,9 +67,8 @@ function _drupal_maintenance_theme() {
 
   // Ensure that system.module is loaded.
   if (!function_exists('_system_rebuild_theme_data')) {
-    $module_list['system'] = 'core/modules/system/system.module';
     $module_handler = \Drupal::moduleHandler();
-    $module_handler->setModuleList($module_list);
+    $module_handler->add('system', 'core/modules/system');
     $module_handler->load('system');
   }
 
diff --git a/core/lib/Drupal/Core/DrupalKernel.php b/core/lib/Drupal/Core/DrupalKernel.php
index 218e7da..054fa0c 100644
--- a/core/lib/Drupal/Core/DrupalKernel.php
+++ b/core/lib/Drupal/Core/DrupalKernel.php
@@ -81,12 +81,9 @@ class DrupalKernel implements DrupalKernelInterface, TerminableInterface {
   protected $newModuleList;
 
   /**
-   * An array of module data objects.
+   * List of available modules and installation profiles.
    *
-   * The data objects have the same data structure as returned by
-   * ExtensionDiscovery but only the uri property is used.
-   *
-   * @var array
+   * @var \Drupal\Core\Extension\Extension[]
    */
   protected $moduleData = array();
 
@@ -330,8 +327,8 @@ protected function moduleData($module) {
    */
   public function updateModules(array $module_list, array $module_filenames = array()) {
     $this->newModuleList = $module_list;
-    foreach ($module_filenames as $module => $filename) {
-      $this->moduleData[$module] = (object) array('uri' => $filename);
+    foreach ($module_filenames as $name => $extension) {
+      $this->moduleData[$name] = $extension;
     }
     // If we haven't yet booted, we don't need to do anything: the new module
     // list will take effect when boot() is called. If we have already booted,
@@ -414,7 +411,7 @@ protected function initializeContainer() {
       // from the container.
       $container_modules = $this->container->getParameter('container.modules');
       $namespaces_before = $this->classLoader->getPrefixes();
-      $this->registerNamespaces($this->getModuleNamespaces($container_modules));
+      $this->registerNamespaces($this->container->getParameter('container.namespaces'));
 
       // If 'container.modules' is wrong, the container must be rebuilt.
       if (!isset($this->moduleList)) {
@@ -502,7 +499,7 @@ protected function buildContainer() {
     $container = $this->getContainerBuilder();
     $container->set('kernel', $this);
     $container->setParameter('container.service_providers', $this->serviceProviderClasses);
-    $container->setParameter('container.modules', $this->getModuleFileNames());
+    $container->setParameter('container.modules', $this->getModulesParameter());
 
     // Get a list of namespaces and put it onto the container.
     $namespaces = $this->getModuleNamespaces($this->getModuleFileNames());
@@ -646,13 +643,32 @@ protected function storage() {
   }
 
   /**
+   * Returns an array of Extension class parameters for all enabled modules.
+   *
+   * @return array
+   */
+  protected function getModulesParameter() {
+    $extensions = array();
+    foreach ($this->moduleList as $name => $weight) {
+      if ($data = $this->moduleData($name)) {
+        $extensions[$name] = array(
+          'type' => $data->getType(),
+          'pathname' => $data->getPathname(),
+          'filename' => $data->getExtensionFilename(),
+        );
+      }
+    }
+    return $extensions;
+  }
+
+  /**
    * Returns the file name for each enabled module.
    */
   protected function getModuleFileNames() {
     $filenames = array();
     foreach ($this->moduleList as $module => $weight) {
       if ($data = $this->moduleData($module)) {
-        $filenames[$module] = $data->uri;
+        $filenames[$module] = $data->getPathname();
       }
     }
     return $filenames;
diff --git a/core/lib/Drupal/Core/Extension/Extension.php b/core/lib/Drupal/Core/Extension/Extension.php
index 97f3fa3..cc21c53 100644
--- a/core/lib/Drupal/Core/Extension/Extension.php
+++ b/core/lib/Drupal/Core/Extension/Extension.php
@@ -27,19 +27,9 @@ class Extension implements \Serializable {
   protected $pathname;
 
   /**
-   * The relative pathname of the main extension file (e.g., 'core/modules/node/node.module').
-   *
-   * @todo Remove this property and do not require .module/.profile files.
-   * @see https://drupal.org/node/340723
-   *
-   * @var string
-   */
-  public $uri;
-
-  /**
    * The filename of the main extension file (e.g., 'node.module').
    *
-   * @var string
+   * @var string|null
    */
   protected $filename;
 
@@ -61,14 +51,12 @@ class Extension implements \Serializable {
    *   The relative path and filename of the extension's info file; e.g.,
    *   'core/modules/node/node.info.yml'.
    * @param string $filename
-   *   The filename of the main extension file; e.g., 'node.module'.
+   *   (optional) The filename of the main extension file; e.g., 'node.module'.
    */
-  public function __construct($type, $pathname, $filename) {
+  public function __construct($type, $pathname, $filename = NULL) {
     $this->type = $type;
     $this->pathname = $pathname;
-    // Set legacy public properties.
     $this->filename = $filename;
-    $this->uri = dirname($pathname) . '/' . $filename;
   }
 
   /**
@@ -117,6 +105,40 @@ public function getFilename() {
   }
 
   /**
+   * Returns the relative path of the main extension file, if any.
+   *
+   * @return string|null
+   */
+  public function getExtensionPathname() {
+    if ($this->filename) {
+      return $this->getPath() . '/' . $this->filename;
+    }
+  }
+
+  /**
+   * Returns the name of the main extension file, if any.
+   *
+   * @return string|null
+   */
+  public function getExtensionFilename() {
+    return $this->filename;
+  }
+
+  /**
+   * Loads the main extension file, if any.
+   *
+   * @return bool
+   *   TRUE if this extension has a main extension file, FALSE otherwise.
+   */
+  public function load() {
+    if ($this->filename) {
+      include_once DRUPAL_ROOT . '/' . $this->getPath() . '/' . $this->filename;
+      return TRUE;
+    }
+    return FALSE;
+  }
+
+  /**
    * Re-routes method calls to SplFileInfo.
    *
    * Offers all SplFileInfo methods to consumers; e.g., $extension->getMTime().
@@ -153,14 +175,9 @@ public function serialize() {
     $data = array(
       'type' => $this->type,
       'pathname' => $this->pathname,
+      'filename' => $this->filename,
     );
 
-    // Include legacy public properties.
-    // @todo Remove this property and do not require .module/.profile files.
-    // @see https://drupal.org/node/340723
-    // @see Extension::$filename
-    $data['filename'] = basename($this->uri);
-
     // @todo ThemeHandler::listInfo(), ThemeHandler::rebuildThemeData(), and
     //   system_list() are adding custom properties to the Extension object.
     $info = new \ReflectionObject($this);
@@ -178,12 +195,6 @@ public function unserialize($data) {
     $data = unserialize($data);
     $this->type = $data['type'];
     $this->pathname = $data['pathname'];
-
-    // Restore legacy public properties.
-    // @todo Remove these properties and do not require .module/.profile files.
-    // @see https://drupal.org/node/340723
-    // @see Extension::$filename
-    $this->uri = dirname($data['pathname']) . '/' . $data['filename'];
     $this->filename = $data['filename'];
 
     // @todo ThemeHandler::listInfo(), ThemeHandler::rebuildThemeData(), and
diff --git a/core/lib/Drupal/Core/Extension/ExtensionDiscovery.php b/core/lib/Drupal/Core/Extension/ExtensionDiscovery.php
index aba0c2f..e9cfefa 100644
--- a/core/lib/Drupal/Core/Extension/ExtensionDiscovery.php
+++ b/core/lib/Drupal/Core/Extension/ExtensionDiscovery.php
@@ -375,6 +375,9 @@ protected function scanDirectory($dir, $include_tests) {
       else {
         $filename = $name . '.' . $type;
       }
+      if (!file_exists(dirname($pathname) . '/' . $filename)) {
+        $filename = NULL;
+      }
 
       $extension = new Extension($type, $pathname, $filename);
       // Inject the existing RecursiveDirectoryIterator object to avoid
diff --git a/core/lib/Drupal/Core/Extension/ModuleHandler.php b/core/lib/Drupal/Core/Extension/ModuleHandler.php
index 89cd73e..003486f 100644
--- a/core/lib/Drupal/Core/Extension/ModuleHandler.php
+++ b/core/lib/Drupal/Core/Extension/ModuleHandler.php
@@ -30,9 +30,7 @@ class ModuleHandler implements ModuleHandlerInterface {
   /**
    * List of installed modules.
    *
-   * @var array
-   *   An associative array whose keys are the names of the modules and whose
-   *   values are the module filenames.
+   * @var \Drupal\Core\Extension\Extension[]
    */
   protected $moduleList;
 
@@ -69,14 +67,17 @@ class ModuleHandler implements ModuleHandlerInterface {
    *
    * @param array $module_list
    *   An associative array whose keys are the names of installed modules and
-   *   whose values are the module filenames. This is normally the
+   *   whose values are Extension class parameters. This is normally the
    *   %container.modules% parameter being set up by DrupalKernel.
    *
    * @see \Drupal\Core\DrupalKernel
    * @see \Drupal\Core\CoreServiceProvider
    */
   public function __construct(array $module_list = array()) {
-    $this->moduleList = $module_list;
+    $this->moduleList = array();
+    foreach ($module_list as $name => $module) {
+      $this->moduleList[$name] = new Extension($module['type'], $module['pathname'], $module['filename']);
+    }
   }
 
   /**
@@ -88,8 +89,7 @@ public function load($name) {
     }
 
     if (isset($this->moduleList[$name])) {
-      $filename = $this->moduleList[$name];
-      include_once DRUPAL_ROOT . '/' . $filename;
+      $this->moduleList[$name]->load();
       $this->loadedFiles[$name] = TRUE;
       return TRUE;
     }
@@ -101,8 +101,8 @@ public function load($name) {
    */
   public function loadAll() {
     if (!$this->loaded) {
-      foreach ($this->moduleList as $module => $filename) {
-        $this->load($module);
+      foreach ($this->moduleList as $name => $module) {
+        $this->load($name);
       }
       $this->loaded = TRUE;
     }
@@ -140,6 +140,13 @@ public function setModuleList(array $module_list = array()) {
     $this->resetImplementations();
   }
 
+  public function add($name, $path) {
+    $pathname = "$path/$name.info.yml";
+    $filename = file_exists($path . "/$name.module") ? "$name.module" : NULL;
+    $this->moduleList[$name] = new Extension('module', $pathname, $filename);
+    $this->resetImplementations();
+  }
+
   /**
    * Implements \Drupal\Core\Extension\ModuleHandlerInterface::buildModuleDependencies().
    */
@@ -190,7 +197,7 @@ public function loadInclude($module, $type, $name = NULL) {
 
     $name = $name ?: $module;
     if (isset($this->moduleList[$module])) {
-      $file = DRUPAL_ROOT . '/' . dirname($this->moduleList[$module]) . "/$name.$type";
+      $file = DRUPAL_ROOT . '/' . $this->moduleList[$module]->getPath() . "/$name.$type";
       if (is_file($file)) {
         require_once $file;
         return $file;
@@ -586,7 +593,10 @@ public function install(array $module_list, $enable_dependencies = TRUE) {
             $module_filenames[$name] = $current_module_filenames[$name];
           }
           else {
-            $module_filenames[$name] = drupal_get_filename('module', $name);
+            $module_path = drupal_get_path('module', $name);
+            $pathname = "$module_path/$name.info.yml";
+            $filename = file_exists($module_path . "/$name.module") ? "$name.module" : NULL;
+            $module_filenames[$name] = new Extension('module', $pathname, $filename);
           }
         }
 
@@ -819,8 +829,8 @@ protected function removeCacheBins($module) {
    */
   public function getModuleDirectories() {
     $dirs = array();
-    foreach ($this->getModuleList() as $module => $filename) {
-      $dirs[$module] = DRUPAL_ROOT . '/' . dirname($filename);
+    foreach ($this->getModuleList() as $name => $module) {
+      $dirs[$name] = DRUPAL_ROOT . '/' . $module->getPath();
     }
     return $dirs;
   }
diff --git a/core/lib/Drupal/Core/Extension/ThemeHandler.php b/core/lib/Drupal/Core/Extension/ThemeHandler.php
index 060d796..db22e5f 100644
--- a/core/lib/Drupal/Core/Extension/ThemeHandler.php
+++ b/core/lib/Drupal/Core/Extension/ThemeHandler.php
@@ -290,7 +290,7 @@ public function rebuildThemeData() {
       // Defaults to 'twig' (see $defaults above).
       $engine = $theme->info['engine'];
       if (isset($engines[$engine])) {
-        $theme->owner = $engines[$engine]->uri;
+        $theme->owner = $engines[$engine]->getExtensionPathname();
         $theme->prefix = $engines[$engine]->getName();
       }
 
diff --git a/core/lib/Drupal/Core/Template/TwigEnvironment.php b/core/lib/Drupal/Core/Template/TwigEnvironment.php
index 06a8dcc..2fed4e4 100644
--- a/core/lib/Drupal/Core/Template/TwigEnvironment.php
+++ b/core/lib/Drupal/Core/Template/TwigEnvironment.php
@@ -40,8 +40,8 @@ public function __construct(\Twig_LoaderInterface $loader = NULL, $options = arr
 
     // Set twig path namespace for themes and modules.
     $namespaces = array();
-    foreach ($module_handler->getModuleList() as $name => $filename) {
-      $namespaces[$name] = dirname($filename);
+    foreach ($module_handler->getModuleList() as $name => $extension) {
+      $namespaces[$name] = $extension->getPath();
     }
     foreach ($theme_handler->listInfo() as $name => $extension) {
       $namespaces[$name] = $extension->getPath();
diff --git a/core/modules/action/tests/action_bulk_test/action_bulk_test.module b/core/modules/action/tests/action_bulk_test/action_bulk_test.module
deleted file mode 100644
index b3d9bbc..0000000
--- a/core/modules/action/tests/action_bulk_test/action_bulk_test.module
+++ /dev/null
@@ -1 +0,0 @@
-<?php
diff --git a/core/modules/aggregator/tests/modules/aggregator_test/aggregator_test.module b/core/modules/aggregator/tests/modules/aggregator_test/aggregator_test.module
deleted file mode 100644
index b3d9bbc..0000000
--- a/core/modules/aggregator/tests/modules/aggregator_test/aggregator_test.module
+++ /dev/null
@@ -1 +0,0 @@
-<?php
diff --git a/core/modules/aggregator/tests/modules/aggregator_test_views/aggregator_test_views.module b/core/modules/aggregator/tests/modules/aggregator_test_views/aggregator_test_views.module
deleted file mode 100644
index b3d9bbc..0000000
--- a/core/modules/aggregator/tests/modules/aggregator_test_views/aggregator_test_views.module
+++ /dev/null
@@ -1 +0,0 @@
-<?php
diff --git a/core/modules/block/tests/modules/block_test_views/block_test_views.module b/core/modules/block/tests/modules/block_test_views/block_test_views.module
deleted file mode 100644
index b3d9bbc..0000000
--- a/core/modules/block/tests/modules/block_test_views/block_test_views.module
+++ /dev/null
@@ -1 +0,0 @@
-<?php
diff --git a/core/modules/comment/tests/modules/comment_test_views/comment_test_views.module b/core/modules/comment/tests/modules/comment_test_views/comment_test_views.module
deleted file mode 100644
index b3d9bbc..0000000
--- a/core/modules/comment/tests/modules/comment_test_views/comment_test_views.module
+++ /dev/null
@@ -1 +0,0 @@
-<?php
diff --git a/core/modules/config/tests/config_events_test/config_events_test.module b/core/modules/config/tests/config_events_test/config_events_test.module
deleted file mode 100644
index aa52475..0000000
--- a/core/modules/config/tests/config_events_test/config_events_test.module
+++ /dev/null
@@ -1,6 +0,0 @@
-<?php
-
-/**
- * @file
- * Provides Config event listeners for testing purposes.
- */
diff --git a/core/modules/config/tests/config_integration_test/config_integration_test.module b/core/modules/config/tests/config_integration_test/config_integration_test.module
deleted file mode 100644
index 9c92696..0000000
--- a/core/modules/config/tests/config_integration_test/config_integration_test.module
+++ /dev/null
@@ -1,6 +0,0 @@
-<?php
-
-/**
- * @file
- * ConfigTest entity integration test module.
- */
diff --git a/core/modules/config/tests/config_other_module_config/config_other_module_config.module b/core/modules/config/tests/config_other_module_config/config_other_module_config.module
deleted file mode 100644
index 3d68fc0..0000000
--- a/core/modules/config/tests/config_other_module_config/config_other_module_config.module
+++ /dev/null
@@ -1,6 +0,0 @@
-<?php
-
-/**
- * @file
- * Test module which supplies a configuration entity owned by another module.
- */
diff --git a/core/modules/config/tests/config_override/config_override.module b/core/modules/config/tests/config_override/config_override.module
deleted file mode 100644
index 0261055..0000000
--- a/core/modules/config/tests/config_override/config_override.module
+++ /dev/null
@@ -1,6 +0,0 @@
-<?php
-
-/**
- * @file
- * Provides Config module for testing overrides.
- */
diff --git a/core/modules/config/tests/config_test_invalid_name/config_test_invalid_name.module b/core/modules/config/tests/config_test_invalid_name/config_test_invalid_name.module
deleted file mode 100644
index 890776d..0000000
--- a/core/modules/config/tests/config_test_invalid_name/config_test_invalid_name.module
+++ /dev/null
@@ -1,6 +0,0 @@
-<?php
-
-/**
- * @file
- * Test module containing a configuration file with an invalid name.
- */
diff --git a/core/modules/config_translation/lib/Drupal/config_translation/ConfigMapperManager.php b/core/modules/config_translation/lib/Drupal/config_translation/ConfigMapperManager.php
index 1227382..bdfbe55 100644
--- a/core/modules/config_translation/lib/Drupal/config_translation/ConfigMapperManager.php
+++ b/core/modules/config_translation/lib/Drupal/config_translation/ConfigMapperManager.php
@@ -68,8 +68,8 @@ public function __construct(CacheBackendInterface $cache_backend, LanguageManage
 
     // Look at all themes and modules.
     $directories = array();
-    foreach ($module_handler->getModuleList() as $module => $filename) {
-      $directories[$module] = dirname($filename);
+    foreach ($module_handler->getModuleList() as $name => $module) {
+      $directories[$name] = $module->getPath();
     }
     foreach ($theme_handler->listInfo() as $theme) {
       $directories[$theme->getName()] = $theme->getPath();
diff --git a/core/modules/contact/tests/modules/contact_test_views/contact_test_views.module b/core/modules/contact/tests/modules/contact_test_views/contact_test_views.module
deleted file mode 100644
index b3d9bbc..0000000
--- a/core/modules/contact/tests/modules/contact_test_views/contact_test_views.module
+++ /dev/null
@@ -1 +0,0 @@
-<?php
diff --git a/core/modules/content_translation/tests/modules/content_translation_test_views/content_translation_test_views.module b/core/modules/content_translation/tests/modules/content_translation_test_views/content_translation_test_views.module
deleted file mode 100644
index b3d9bbc..0000000
--- a/core/modules/content_translation/tests/modules/content_translation_test_views/content_translation_test_views.module
+++ /dev/null
@@ -1 +0,0 @@
-<?php
diff --git a/core/modules/dblog/tests/modules/dblog_test_views/dblog_test_views.module b/core/modules/dblog/tests/modules/dblog_test_views/dblog_test_views.module
deleted file mode 100644
index b3d9bbc..0000000
--- a/core/modules/dblog/tests/modules/dblog_test_views/dblog_test_views.module
+++ /dev/null
@@ -1 +0,0 @@
-<?php
diff --git a/core/modules/entity_reference/tests/modules/entity_reference_test/entity_reference_test.module b/core/modules/entity_reference/tests/modules/entity_reference_test/entity_reference_test.module
deleted file mode 100644
index 37dc050..0000000
--- a/core/modules/entity_reference/tests/modules/entity_reference_test/entity_reference_test.module
+++ /dev/null
@@ -1,6 +0,0 @@
-<?php
-
-/**
- * @file
- * Helper module for the Entity Reference tests.
- */
diff --git a/core/modules/field/tests/modules/field_test_config/field_test_config.module b/core/modules/field/tests/modules/field_test_config/field_test_config.module
deleted file mode 100644
index 3d7730d..0000000
--- a/core/modules/field/tests/modules/field_test_config/field_test_config.module
+++ /dev/null
@@ -1,6 +0,0 @@
-<?php
-
-/**
- * @file
- * Helper module for the Field API configuration tests.
- */
diff --git a/core/modules/field/tests/modules/field_test_views/field_test_views.module b/core/modules/field/tests/modules/field_test_views/field_test_views.module
deleted file mode 100644
index b3d9bbc..0000000
--- a/core/modules/field/tests/modules/field_test_views/field_test_views.module
+++ /dev/null
@@ -1 +0,0 @@
-<?php
diff --git a/core/modules/field_ui/tests/modules/field_ui_test/field_ui_test.module b/core/modules/field_ui/tests/modules/field_ui_test/field_ui_test.module
deleted file mode 100644
index dae31c6..0000000
--- a/core/modules/field_ui/tests/modules/field_ui_test/field_ui_test.module
+++ /dev/null
@@ -1,6 +0,0 @@
-<?php
-
-/**
- * @file
- * Field UI test module.
- */
diff --git a/core/modules/file/tests/modules/file_test_views/file_test_views.module b/core/modules/file/tests/modules/file_test_views/file_test_views.module
deleted file mode 100644
index b3d9bbc..0000000
--- a/core/modules/file/tests/modules/file_test_views/file_test_views.module
+++ /dev/null
@@ -1 +0,0 @@
-<?php
diff --git a/core/modules/forum/tests/modules/forum_test_views/forum_test_views.module b/core/modules/forum/tests/modules/forum_test_views/forum_test_views.module
deleted file mode 100644
index b3d9bbc..0000000
--- a/core/modules/forum/tests/modules/forum_test_views/forum_test_views.module
+++ /dev/null
@@ -1 +0,0 @@
-<?php
diff --git a/core/modules/migrate/migrate.module b/core/modules/migrate/migrate.module
deleted file mode 100644
index e69de29..0000000
diff --git a/core/modules/migrate_drupal/migrate_drupal.module b/core/modules/migrate_drupal/migrate_drupal.module
deleted file mode 100644
index e69de29..0000000
diff --git a/core/modules/node/tests/modules/node_test_config/node_test_config.module b/core/modules/node/tests/modules/node_test_config/node_test_config.module
deleted file mode 100644
index 00522b5..0000000
--- a/core/modules/node/tests/modules/node_test_config/node_test_config.module
+++ /dev/null
@@ -1,6 +0,0 @@
-<?php
-
-/**
- * @file
- * Helper module for node configuration tests.
- */
diff --git a/core/modules/node/tests/modules/node_test_views/node_test_views.module b/core/modules/node/tests/modules/node_test_views/node_test_views.module
deleted file mode 100644
index b3d9bbc..0000000
--- a/core/modules/node/tests/modules/node_test_views/node_test_views.module
+++ /dev/null
@@ -1 +0,0 @@
-<?php
diff --git a/core/modules/rest/tests/modules/rest_test_views/rest_test_views.module b/core/modules/rest/tests/modules/rest_test_views/rest_test_views.module
deleted file mode 100644
index b3d9bbc..0000000
--- a/core/modules/rest/tests/modules/rest_test_views/rest_test_views.module
+++ /dev/null
@@ -1 +0,0 @@
-<?php
diff --git a/core/modules/search/tests/modules/search_extra_type/search_extra_type.module b/core/modules/search/tests/modules/search_extra_type/search_extra_type.module
deleted file mode 100644
index 4600708..0000000
--- a/core/modules/search/tests/modules/search_extra_type/search_extra_type.module
+++ /dev/null
@@ -1,7 +0,0 @@
-<?php
-
-/**
- * @file
- * Dummy module implementing a search type for search module testing.
- */
-
diff --git a/core/modules/serialization/tests/serialization_test/serialization_test.module b/core/modules/serialization/tests/serialization_test/serialization_test.module
deleted file mode 100644
index c4e35c7..0000000
--- a/core/modules/serialization/tests/serialization_test/serialization_test.module
+++ /dev/null
@@ -1,7 +0,0 @@
-<?php
-
-/**
- * @file
- * Helper module for serialization tests. This file is empty, because all
- * implementation is in autoloaded classes.
- */
diff --git a/core/modules/simpletest/lib/Drupal/simpletest/DrupalUnitTestBase.php b/core/modules/simpletest/lib/Drupal/simpletest/DrupalUnitTestBase.php
index d10ce9f..ab18f48 100644
--- a/core/modules/simpletest/lib/Drupal/simpletest/DrupalUnitTestBase.php
+++ b/core/modules/simpletest/lib/Drupal/simpletest/DrupalUnitTestBase.php
@@ -343,19 +343,17 @@ protected function installSchema($module, $tables) {
   protected function enableModules(array $modules) {
     // Set the list of modules in the extension handler.
     $module_handler = $this->container->get('module_handler');
-    $module_filenames = $module_handler->getModuleList();
     // Write directly to active storage to avoid early instantiation of
     // the event dispatcher which can prevent modules from registering events.
     $active_storage =  \Drupal::service('config.storage');
     $system_config = $active_storage->read('system.module');
     foreach ($modules as $module) {
-      $module_filenames[$module] = drupal_get_filename('module', $module);
+      $module_handler->add($module, drupal_get_path('module', $module));
       // Maintain the list of enabled modules in configuration.
       $system_config['enabled'][$module] = 0;
     }
     $active_storage->write('system.module', $system_config);
-    $module_handler->setModuleList($module_filenames);
-    $module_handler->resetImplementations();
+    $module_filenames = $module_handler->getModuleList();
     // Update the kernel to make their services available.
     $this->kernel->updateModules($module_filenames, $module_filenames);
 
diff --git a/core/modules/simpletest/simpletest.module b/core/modules/simpletest/simpletest.module
index 8da7e4c..9b6e9cc 100644
--- a/core/modules/simpletest/simpletest.module
+++ b/core/modules/simpletest/simpletest.module
@@ -552,7 +552,7 @@ function simpletest_classloader_register() {
     $extensions = array();
     foreach ($types as $type) {
       foreach ($listing->scan($type, TRUE) as $name => $file) {
-        $extensions[$type][$name] = $file->uri;
+        $extensions[$type][$name] = $file->getPathname();
       }
     }
     \Drupal::cache()->set($cid, $extensions);
diff --git a/core/modules/statistics/tests/modules/statistics_test_views/statistics_test_views.module b/core/modules/statistics/tests/modules/statistics_test_views/statistics_test_views.module
deleted file mode 100644
index e69de29..0000000
diff --git a/core/modules/system/system.module b/core/modules/system/system.module
index 60c7c4e..e58c1cf 100644
--- a/core/modules/system/system.module
+++ b/core/modules/system/system.module
@@ -1463,7 +1463,7 @@ function system_rebuild_module_data() {
       $module->weight = isset($installed_modules[$name]) ? $installed_modules[$name] : 0;
       $module->status = (int) isset($installed_modules[$name]);
       $module->schema_version = SCHEMA_UNINSTALLED;
-      $files[$name] = $module->uri;
+      $files[$name] = $module->getPathname();
     }
     $modules = \Drupal::moduleHandler()->buildModuleDependencies($modules);
     $modules_cache = $modules;
@@ -1510,7 +1510,7 @@ function system_rebuild_theme_data() {
   $files = array();
   foreach ($themes as $name => $theme) {
     $theme->status = (int) isset($enabled_themes[$name]);
-    $files[$name] = $theme->uri;
+    $files[$name] = $theme->getPathname();
   }
   // Replace last known theme data state.
   // @todo Obsolete with proper installation status for themes.
diff --git a/core/modules/system/tests/modules/action_test/action_test.module b/core/modules/system/tests/modules/action_test/action_test.module
deleted file mode 100644
index b3d9bbc..0000000
--- a/core/modules/system/tests/modules/action_test/action_test.module
+++ /dev/null
@@ -1 +0,0 @@
-<?php
diff --git a/core/modules/system/tests/modules/cache_test/cache_test.module b/core/modules/system/tests/modules/cache_test/cache_test.module
deleted file mode 100644
index 3d2e68d..0000000
--- a/core/modules/system/tests/modules/cache_test/cache_test.module
+++ /dev/null
@@ -1,6 +0,0 @@
-<?php
-
-/**
- * @file
- * Support module for testing the cache system.
- */
diff --git a/core/modules/system/tests/modules/condition_test/condition_test.module b/core/modules/system/tests/modules/condition_test/condition_test.module
deleted file mode 100644
index b3d9bbc..0000000
--- a/core/modules/system/tests/modules/condition_test/condition_test.module
+++ /dev/null
@@ -1 +0,0 @@
-<?php
diff --git a/core/modules/system/tests/modules/drupal_system_listing_compatible_test/drupal_system_listing_compatible_test.module b/core/modules/system/tests/modules/drupal_system_listing_compatible_test/drupal_system_listing_compatible_test.module
deleted file mode 100644
index b3d9bbc..0000000
--- a/core/modules/system/tests/modules/drupal_system_listing_compatible_test/drupal_system_listing_compatible_test.module
+++ /dev/null
@@ -1 +0,0 @@
-<?php
diff --git a/core/modules/system/tests/modules/drupal_system_listing_incompatible_test/drupal_system_listing_incompatible_test.module b/core/modules/system/tests/modules/drupal_system_listing_incompatible_test/drupal_system_listing_incompatible_test.module
deleted file mode 100644
index b3d9bbc..0000000
--- a/core/modules/system/tests/modules/drupal_system_listing_incompatible_test/drupal_system_listing_incompatible_test.module
+++ /dev/null
@@ -1 +0,0 @@
-<?php
diff --git a/core/modules/system/tests/modules/error_test/error_test.module b/core/modules/system/tests/modules/error_test/error_test.module
deleted file mode 100644
index b3d9bbc..0000000
--- a/core/modules/system/tests/modules/error_test/error_test.module
+++ /dev/null
@@ -1 +0,0 @@
-<?php
diff --git a/core/modules/system/tests/modules/image_test/image_test.module b/core/modules/system/tests/modules/image_test/image_test.module
deleted file mode 100644
index 92f1ca2..0000000
--- a/core/modules/system/tests/modules/image_test/image_test.module
+++ /dev/null
@@ -1,6 +0,0 @@
-<?php
-
-/**
- * @file
- * Helper module for the image tests.
- */
diff --git a/core/modules/system/tests/modules/invalid_module_name_over_the_maximum_allowed_character_length/invalid_module_name_over_the_maximum_allowed_character_length.module b/core/modules/system/tests/modules/invalid_module_name_over_the_maximum_allowed_character_length/invalid_module_name_over_the_maximum_allowed_character_length.module
deleted file mode 100644
index d0dc049..0000000
--- a/core/modules/system/tests/modules/invalid_module_name_over_the_maximum_allowed_character_length/invalid_module_name_over_the_maximum_allowed_character_length.module
+++ /dev/null
@@ -1,8 +0,0 @@
-<?php
-
-/**
- * @file
- * Module with a module name over the maximum allowed number of characters.
- *
- * @see DRUPAL_MODULE_NAME_MAX_LENGTH
- */
diff --git a/core/modules/system/tests/modules/module_autoload_test/module_autoload_test.module b/core/modules/system/tests/modules/module_autoload_test/module_autoload_test.module
deleted file mode 100644
index a4abe2d..0000000
--- a/core/modules/system/tests/modules/module_autoload_test/module_autoload_test.module
+++ /dev/null
@@ -1,2 +0,0 @@
-<?php
-
diff --git a/core/modules/system/tests/modules/paramconverter_test/paramconverter_test.module b/core/modules/system/tests/modules/paramconverter_test/paramconverter_test.module
deleted file mode 100644
index c37a9e2..0000000
--- a/core/modules/system/tests/modules/paramconverter_test/paramconverter_test.module
+++ /dev/null
@@ -1,6 +0,0 @@
-<?php
-
-/**
- * @file
- * Intentionally blank file.
- */
diff --git a/core/modules/system/tests/modules/requirements1_test/requirements1_test.module b/core/modules/system/tests/modules/requirements1_test/requirements1_test.module
deleted file mode 100644
index e52266b..0000000
--- a/core/modules/system/tests/modules/requirements1_test/requirements1_test.module
+++ /dev/null
@@ -1,7 +0,0 @@
-<?php
-
-/**
- * @file
- * Tests that a module is not installed when it fails
- * hook_requirements('install').
- */
diff --git a/core/modules/system/tests/modules/requirements2_test/requirements2_test.module b/core/modules/system/tests/modules/requirements2_test/requirements2_test.module
deleted file mode 100644
index a4f4305..0000000
--- a/core/modules/system/tests/modules/requirements2_test/requirements2_test.module
+++ /dev/null
@@ -1,7 +0,0 @@
-<?php
-
-/**
- * @file
- * Tests that a module is not installed when the one it depends on fails
- * hook_requirements('install').
- */
diff --git a/core/modules/system/tests/modules/service_provider_test/service_provider_test.module b/core/modules/system/tests/modules/service_provider_test/service_provider_test.module
deleted file mode 100644
index b3d9bbc..0000000
--- a/core/modules/system/tests/modules/service_provider_test/service_provider_test.module
+++ /dev/null
@@ -1 +0,0 @@
-<?php
diff --git a/core/modules/system/tests/modules/system_dependencies_test/system_dependencies_test.module b/core/modules/system/tests/modules/system_dependencies_test/system_dependencies_test.module
deleted file mode 100644
index b3d9bbc..0000000
--- a/core/modules/system/tests/modules/system_dependencies_test/system_dependencies_test.module
+++ /dev/null
@@ -1 +0,0 @@
-<?php
diff --git a/core/modules/system/tests/modules/system_incompatible_core_version_dependencies_test/system_incompatible_core_version_dependencies_test.module b/core/modules/system/tests/modules/system_incompatible_core_version_dependencies_test/system_incompatible_core_version_dependencies_test.module
deleted file mode 100644
index b3d9bbc..0000000
--- a/core/modules/system/tests/modules/system_incompatible_core_version_dependencies_test/system_incompatible_core_version_dependencies_test.module
+++ /dev/null
@@ -1 +0,0 @@
-<?php
diff --git a/core/modules/system/tests/modules/system_incompatible_core_version_test/system_incompatible_core_version_test.module b/core/modules/system/tests/modules/system_incompatible_core_version_test/system_incompatible_core_version_test.module
deleted file mode 100644
index b3d9bbc..0000000
--- a/core/modules/system/tests/modules/system_incompatible_core_version_test/system_incompatible_core_version_test.module
+++ /dev/null
@@ -1 +0,0 @@
-<?php
diff --git a/core/modules/system/tests/modules/system_incompatible_module_version_dependencies_test/system_incompatible_module_version_dependencies_test.module b/core/modules/system/tests/modules/system_incompatible_module_version_dependencies_test/system_incompatible_module_version_dependencies_test.module
deleted file mode 100644
index b3d9bbc..0000000
--- a/core/modules/system/tests/modules/system_incompatible_module_version_dependencies_test/system_incompatible_module_version_dependencies_test.module
+++ /dev/null
@@ -1 +0,0 @@
-<?php
diff --git a/core/modules/system/tests/modules/system_incompatible_module_version_test/system_incompatible_module_version_test.module b/core/modules/system/tests/modules/system_incompatible_module_version_test/system_incompatible_module_version_test.module
deleted file mode 100644
index b3d9bbc..0000000
--- a/core/modules/system/tests/modules/system_incompatible_module_version_test/system_incompatible_module_version_test.module
+++ /dev/null
@@ -1 +0,0 @@
-<?php
diff --git a/core/modules/system/tests/modules/system_mail_failure_test/system_mail_failure_test.module b/core/modules/system/tests/modules/system_mail_failure_test/system_mail_failure_test.module
deleted file mode 100644
index 6acb6c4..0000000
--- a/core/modules/system/tests/modules/system_mail_failure_test/system_mail_failure_test.module
+++ /dev/null
@@ -1,7 +0,0 @@
-<?php
-
-/**
- * @file
- * Disables the email function for testing purposes.
- */
-
diff --git a/core/modules/system/tests/modules/twig_theme_test/modules/twig_namespace_a/twig_namespace_a.module b/core/modules/system/tests/modules/twig_theme_test/modules/twig_namespace_a/twig_namespace_a.module
deleted file mode 100644
index 37a5536..0000000
--- a/core/modules/system/tests/modules/twig_theme_test/modules/twig_namespace_a/twig_namespace_a.module
+++ /dev/null
@@ -1,6 +0,0 @@
-<?php
-
-/**
- * @file
- * twig_namespace_a.module
- */
diff --git a/core/modules/system/tests/modules/twig_theme_test/modules/twig_namespace_b/twig_namespace_b.module b/core/modules/system/tests/modules/twig_theme_test/modules/twig_namespace_b/twig_namespace_b.module
deleted file mode 100644
index 03d8ef7..0000000
--- a/core/modules/system/tests/modules/twig_theme_test/modules/twig_namespace_b/twig_namespace_b.module
+++ /dev/null
@@ -1,6 +0,0 @@
-<?php
-
-/**
- * @file
- * twig_namespace_b.module
- */
diff --git a/core/modules/system/tests/modules/update_test_0/update_test_0.module b/core/modules/system/tests/modules/update_test_0/update_test_0.module
deleted file mode 100644
index b3d9bbc..0000000
--- a/core/modules/system/tests/modules/update_test_0/update_test_0.module
+++ /dev/null
@@ -1 +0,0 @@
-<?php
diff --git a/core/modules/system/tests/modules/update_test_1/update_test_1.module b/core/modules/system/tests/modules/update_test_1/update_test_1.module
deleted file mode 100644
index b3d9bbc..0000000
--- a/core/modules/system/tests/modules/update_test_1/update_test_1.module
+++ /dev/null
@@ -1 +0,0 @@
-<?php
diff --git a/core/modules/system/tests/modules/update_test_2/update_test_2.module b/core/modules/system/tests/modules/update_test_2/update_test_2.module
deleted file mode 100644
index b3d9bbc..0000000
--- a/core/modules/system/tests/modules/update_test_2/update_test_2.module
+++ /dev/null
@@ -1 +0,0 @@
-<?php
diff --git a/core/modules/system/tests/modules/update_test_3/update_test_3.module b/core/modules/system/tests/modules/update_test_3/update_test_3.module
deleted file mode 100644
index b3d9bbc..0000000
--- a/core/modules/system/tests/modules/update_test_3/update_test_3.module
+++ /dev/null
@@ -1 +0,0 @@
-<?php
diff --git a/core/modules/system/tests/modules/update_test_invalid_hook/update_test_invalid_hook.module b/core/modules/system/tests/modules/update_test_invalid_hook/update_test_invalid_hook.module
deleted file mode 100644
index b3d9bbc..0000000
--- a/core/modules/system/tests/modules/update_test_invalid_hook/update_test_invalid_hook.module
+++ /dev/null
@@ -1 +0,0 @@
-<?php
diff --git a/core/modules/system/tests/modules/update_test_with_7x/update_test_with_7x.module b/core/modules/system/tests/modules/update_test_with_7x/update_test_with_7x.module
deleted file mode 100644
index b3d9bbc..0000000
--- a/core/modules/system/tests/modules/update_test_with_7x/update_test_with_7x.module
+++ /dev/null
@@ -1 +0,0 @@
-<?php
diff --git a/core/modules/system/tests/modules/url_alter_test/url_alter_test.module b/core/modules/system/tests/modules/url_alter_test/url_alter_test.module
deleted file mode 100644
index b3d9bbc..0000000
--- a/core/modules/system/tests/modules/url_alter_test/url_alter_test.module
+++ /dev/null
@@ -1 +0,0 @@
-<?php
diff --git a/core/modules/taxonomy/tests/modules/taxonomy_test_views/taxonomy_test_views.module b/core/modules/taxonomy/tests/modules/taxonomy_test_views/taxonomy_test_views.module
deleted file mode 100644
index b3d9bbc..0000000
--- a/core/modules/taxonomy/tests/modules/taxonomy_test_views/taxonomy_test_views.module
+++ /dev/null
@@ -1 +0,0 @@
-<?php
diff --git a/core/modules/tracker/tests/modules/tracker_test_views/tracker_test_views.module b/core/modules/tracker/tests/modules/tracker_test_views/tracker_test_views.module
deleted file mode 100644
index b3d9bbc..0000000
--- a/core/modules/tracker/tests/modules/tracker_test_views/tracker_test_views.module
+++ /dev/null
@@ -1 +0,0 @@
-<?php
diff --git a/core/modules/update/tests/aaa_update_test/aaa_update_test.module b/core/modules/update/tests/aaa_update_test/aaa_update_test.module
deleted file mode 100644
index 4d67b8e..0000000
--- a/core/modules/update/tests/aaa_update_test/aaa_update_test.module
+++ /dev/null
@@ -1,6 +0,0 @@
-<?php
-
-/**
- * @file
- * Dummy module for testing Update status.
- */
diff --git a/core/modules/update/tests/modules/aaa_update_test/aaa_update_test.module b/core/modules/update/tests/modules/aaa_update_test/aaa_update_test.module
deleted file mode 100644
index 4d67b8e..0000000
--- a/core/modules/update/tests/modules/aaa_update_test/aaa_update_test.module
+++ /dev/null
@@ -1,6 +0,0 @@
-<?php
-
-/**
- * @file
- * Dummy module for testing Update status.
- */
diff --git a/core/modules/update/tests/modules/bbb_update_test/bbb_update_test.module b/core/modules/update/tests/modules/bbb_update_test/bbb_update_test.module
deleted file mode 100644
index 4d67b8e..0000000
--- a/core/modules/update/tests/modules/bbb_update_test/bbb_update_test.module
+++ /dev/null
@@ -1,6 +0,0 @@
-<?php
-
-/**
- * @file
- * Dummy module for testing Update status.
- */
diff --git a/core/modules/update/tests/modules/ccc_update_test/ccc_update_test.module b/core/modules/update/tests/modules/ccc_update_test/ccc_update_test.module
deleted file mode 100644
index 4d67b8e..0000000
--- a/core/modules/update/tests/modules/ccc_update_test/ccc_update_test.module
+++ /dev/null
@@ -1,6 +0,0 @@
-<?php
-
-/**
- * @file
- * Dummy module for testing Update status.
- */
diff --git a/core/modules/user/tests/modules/user_custom_phpass_params_test/user_custom_phpass_params_test.module b/core/modules/user/tests/modules/user_custom_phpass_params_test/user_custom_phpass_params_test.module
deleted file mode 100644
index e69de29..0000000
diff --git a/core/modules/user/tests/modules/user_form_test/user_form_test.module b/core/modules/user/tests/modules/user_form_test/user_form_test.module
deleted file mode 100644
index aefc9d3..0000000
--- a/core/modules/user/tests/modules/user_form_test/user_form_test.module
+++ /dev/null
@@ -1,6 +0,0 @@
-<?php
-
-/**
- * @file
- * Dummy module implementing a form to test user password validation
- */
diff --git a/core/modules/user/tests/modules/user_test_views/user_test_views.module b/core/modules/user/tests/modules/user_test_views/user_test_views.module
deleted file mode 100644
index b3d9bbc..0000000
--- a/core/modules/user/tests/modules/user_test_views/user_test_views.module
+++ /dev/null
@@ -1 +0,0 @@
-<?php
diff --git a/core/modules/views/tests/modules/views_test_config/views_test_config.module b/core/modules/views/tests/modules/views_test_config/views_test_config.module
deleted file mode 100644
index b3d9bbc..0000000
--- a/core/modules/views/tests/modules/views_test_config/views_test_config.module
+++ /dev/null
@@ -1 +0,0 @@
-<?php
diff --git a/core/profiles/testing/modules/drupal_system_listing_compatible_test/drupal_system_listing_compatible_test.module b/core/profiles/testing/modules/drupal_system_listing_compatible_test/drupal_system_listing_compatible_test.module
deleted file mode 100644
index b3d9bbc..0000000
--- a/core/profiles/testing/modules/drupal_system_listing_compatible_test/drupal_system_listing_compatible_test.module
+++ /dev/null
@@ -1 +0,0 @@
-<?php
diff --git a/core/profiles/testing/modules/drupal_system_listing_incompatible_test/drupal_system_listing_incompatible_test.module b/core/profiles/testing/modules/drupal_system_listing_incompatible_test/drupal_system_listing_incompatible_test.module
deleted file mode 100644
index b3d9bbc..0000000
--- a/core/profiles/testing/modules/drupal_system_listing_incompatible_test/drupal_system_listing_incompatible_test.module
+++ /dev/null
@@ -1 +0,0 @@
-<?php
diff --git a/core/profiles/testing/testing.profile b/core/profiles/testing/testing.profile
deleted file mode 100644
index 3df8aa2..0000000
--- a/core/profiles/testing/testing.profile
+++ /dev/null
@@ -1,5 +0,0 @@
-<?php
-/**
- * @file
- * Installation profile for tests.
- */
diff --git a/core/tests/Drupal/Tests/Core/Extension/ThemeHandlerTest.php b/core/tests/Drupal/Tests/Core/Extension/ThemeHandlerTest.php
index bae3c9a..94df741 100644
--- a/core/tests/Drupal/Tests/Core/Extension/ThemeHandlerTest.php
+++ b/core/tests/Drupal/Tests/Core/Extension/ThemeHandlerTest.php
@@ -269,7 +269,7 @@ public function testRebuildThemeData() {
     $this->assertInstanceOf('Drupal\Core\Extension\Extension', $info);
     $this->assertEquals('seven', $info->getName());
     $this->assertEquals(DRUPAL_ROOT . '/core/themes/seven/seven.info.yml', $info->getPathname());
-    $this->assertEquals(DRUPAL_ROOT . '/core/themes/seven/seven.theme', $info->uri);
+    $this->assertEquals(DRUPAL_ROOT . '/core/themes/seven/seven.theme', $info->getExtensionPathname());
     $this->assertEquals(DRUPAL_ROOT . '/core/themes/engines/twig/twig.engine', $info->owner);
     $this->assertEquals('twig', $info->prefix);
 
diff --git a/core/themes/engines/phptemplate/phptemplate.engine b/core/themes/engines/phptemplate/phptemplate.engine
index cab86fd..0521092 100644
--- a/core/themes/engines/phptemplate/phptemplate.engine
+++ b/core/themes/engines/phptemplate/phptemplate.engine
@@ -11,9 +11,7 @@
  * Implements hook_init().
  */
 function phptemplate_init(Extension $theme) {
-  if (file_exists($theme->uri)) {
-    include_once DRUPAL_ROOT . '/' . $theme->uri;
-  }
+  $theme->load();
 }
 
 /**
diff --git a/core/themes/engines/twig/twig.engine b/core/themes/engines/twig/twig.engine
index 2985ddc..fd988da 100644
--- a/core/themes/engines/twig/twig.engine
+++ b/core/themes/engines/twig/twig.engine
@@ -28,9 +28,7 @@ function twig_extension() {
  * Implements hook_init().
  */
 function twig_init(Extension $theme) {
-  if (file_exists($theme->uri)) {
-    include_once DRUPAL_ROOT . '/' . $theme->uri;
-  }
+  $theme->load();
 }
 
 /**
diff --git a/core/update.php b/core/update.php
index 433d5cf..1adf244 100644
--- a/core/update.php
+++ b/core/update.php
@@ -252,9 +252,8 @@ function update_access_allowed() {
   // so we fall back on requiring that the user be logged in as user #1.
   try {
     $module_handler = \Drupal::moduleHandler();
+    $module_handler->add('user', 'core/modules/user');
     $module_filenames = $module_handler->getModuleList();
-    $module_filenames['user'] = 'core/modules/user/user.module';
-    $module_handler->setModuleList($module_filenames);
     $module_handler->reload();
     \Drupal::service('kernel')->updateModules($module_filenames, $module_filenames);
     return user_access('administer software updates');