diff --git a/advanced_search.module b/advanced_search.module
index ed42223..7c55b92 100644
--- a/advanced_search.module
+++ b/advanced_search.module
@@ -40,7 +40,8 @@ function advanced_search_theme() {
 function advanced_search_library_info_alter(&$libraries, $extension) {
   if ($extension == 'facets') {
     // Override facets module javascript with customizations.
-    $path = '/' . drupal_get_path('module', 'advanced_search') . '/js/facets';
+    // https://www.drupal.org/node/2940438
+    $path = '/' . \Drupal::service('extension.list.module')->getPath('advanced_search') . '/js/facets';
     $libraries['soft-limit']['js'] = [
       "$path/soft-limit.js" => [],
     ];
diff --git a/src/Controller/AjaxBlocksController.php b/src/Controller/AjaxBlocksController.php
index c5e3fb8..74d1652 100644
--- a/src/Controller/AjaxBlocksController.php
+++ b/src/Controller/AjaxBlocksController.php
@@ -84,7 +84,7 @@ class AjaxBlocksController extends ControllerBase {
    * @param \Symfony\Component\DependencyInjection\ContainerInterface $container
    *   The drupal container.
    */
-  public function __construct(RendererInterface $renderer, CurrentPathStack $currentPath, RouterInterface $router, PathProcessorManager $pathProcessor, CurrentRouteMatch $currentRouteMatch, ContainerInterface $container) {
+  final public function __construct(RendererInterface $renderer, CurrentPathStack $currentPath, RouterInterface $router, PathProcessorManager $pathProcessor, CurrentRouteMatch $currentRouteMatch, ContainerInterface $container) {
     $this->storage = $this->entityTypeManager()->getStorage('block');
     $this->renderer = $renderer;
     $this->currentPath = $currentPath;
diff --git a/src/Form/AdvancedSearchForm.php b/src/Form/AdvancedSearchForm.php
index 372c2c0..bba7448 100644
--- a/src/Form/AdvancedSearchForm.php
+++ b/src/Form/AdvancedSearchForm.php
@@ -61,7 +61,7 @@ class AdvancedSearchForm extends FormBase {
   /**
    * Class constructor.
    */
-  public function __construct(Request $request, RouteMatchInterface $current_route_match) {
+  final public function __construct(Request $request, RouteMatchInterface $current_route_match) {
     $this->request = $request;
     $this->currentRouteMatch = $current_route_match;
   }
diff --git a/src/Form/SettingsForm.php b/src/Form/SettingsForm.php
index 5f511df..5c6fef9 100644
--- a/src/Form/SettingsForm.php
+++ b/src/Form/SettingsForm.php
@@ -35,7 +35,7 @@ class SettingsForm extends ConfigFormBase {
    * @param \Drupal\Core\Config\ConfigFactoryInterface $config_factory
    *   The factory for configuration objects.
    */
-  public function __construct(ConfigFactoryInterface $config_factory) {
+  final public function __construct(ConfigFactoryInterface $config_factory) {
     $this->setConfigFactory($config_factory);
   }
 
diff --git a/src/Plugin/Block/AdvancedSearchBlock.php b/src/Plugin/Block/AdvancedSearchBlock.php
index 22faf05..34bc541 100644
--- a/src/Plugin/Block/AdvancedSearchBlock.php
+++ b/src/Plugin/Block/AdvancedSearchBlock.php
@@ -88,7 +88,7 @@ class AdvancedSearchBlock extends BlockBase implements ContainerFactoryPluginInt
    * @param \Symfony\Component\HttpFoundation\Request $request
    *   A request object for the current request.
    */
-  public function __construct(array $configuration, $plugin_id, $plugin_definition, DisplayPluginManager $display_plugin_manager, FormBuilderInterface $form_builder, Request $request) {
+  final public function __construct(array $configuration, $plugin_id, $plugin_definition, DisplayPluginManager $display_plugin_manager, FormBuilderInterface $form_builder, Request $request) {
     parent::__construct($configuration, $plugin_id, $plugin_definition);
     $this->displayPluginManager = $display_plugin_manager;
     list($view_id, $display_id) = preg_split('/__/', $this->getDerivativeId(), 2);
diff --git a/src/Plugin/Block/SearchApiDisplayBlockDeriver.php b/src/Plugin/Block/SearchApiDisplayBlockDeriver.php
index 9b6011f..ca72b6b 100644
--- a/src/Plugin/Block/SearchApiDisplayBlockDeriver.php
+++ b/src/Plugin/Block/SearchApiDisplayBlockDeriver.php
@@ -40,6 +40,8 @@ abstract class SearchApiDisplayBlockDeriver implements ContainerDeriverInterface
    */
   abstract protected function label();
 
+  final public function __construct (ContainerInterface $container, $base_plugin_id) {}
+
   /**
    * {@inheritdoc}
    */
diff --git a/src/Plugin/Block/SearchResultsPagerBlock.php b/src/Plugin/Block/SearchResultsPagerBlock.php
index 4402519..fdf199f 100644
--- a/src/Plugin/Block/SearchResultsPagerBlock.php
+++ b/src/Plugin/Block/SearchResultsPagerBlock.php
@@ -46,7 +46,7 @@ class SearchResultsPagerBlock extends BlockBase implements ContainerFactoryPlugi
    * @param \Symfony\Component\HttpFoundation\Request $request
    *   A request object for the current request.
    */
-  public function __construct(array $configuration, $plugin_id, $plugin_definition, Request $request) {
+  final public function __construct(array $configuration, $plugin_id, $plugin_definition, Request $request) {
     parent::__construct($configuration, $plugin_id, $plugin_definition);
     $this->request = clone $request;
   }