diff -u b/core/modules/language/src/Plugin/Block/LanguageBlock.php b/core/modules/language/src/Plugin/Block/LanguageBlock.php
--- b/core/modules/language/src/Plugin/Block/LanguageBlock.php
+++ b/core/modules/language/src/Plugin/Block/LanguageBlock.php
@@ -8,7 +8,7 @@
 namespace Drupal\language\Plugin\Block;
 
 use Drupal\Core\Block\BlockBase;
-use Drupal\Core\Path\PathMatcher;
+use Drupal\Core\Path\PathMatcherInterface;
 use Drupal\Core\Session\AccountInterface;
 use Drupal\Core\Language\LanguageManagerInterface;
 use Drupal\Core\Plugin\ContainerFactoryPluginInterface;
@@ -37,7 +37,7 @@
   /**
    * The path matcher.
    *
-   * @var \Drupal\Core\Path\PathMatcher
+   * @var \Drupal\Core\Path\PathMatcherInterface
    */
   protected $pathMatcher;
 
@@ -52,10 +52,10 @@
    *   The plugin implementation definition.
    * @param \Drupal\Core\Language\LanguageManagerInterface $language_manager
    *   The language manager.
-   * @param \Drupal\Core\Path\PathMatcher $path_matcher
+   * @param \Drupal\Core\Path\PathMatcherInterface $path_matcher
    *   The path matcher.
    */
-  public function __construct(array $configuration, $plugin_id, $plugin_definition, LanguageManagerInterface $language_manager, PathMatcher $path_matcher) {
+  public function __construct(array $configuration, $plugin_id, $plugin_definition, LanguageManagerInterface $language_manager, PathMatcherInterface $path_matcher) {
     parent::__construct($configuration, $plugin_id, $plugin_definition);
     $this->languageManager = $language_manager;
     $this->pathMatcher = $path_matcher;