diff -u b/core/modules/forum/src/Breadcrumb/ForumBreadcrumbBuilderBase.php b/core/modules/forum/src/Breadcrumb/ForumBreadcrumbBuilderBase.php
--- b/core/modules/forum/src/Breadcrumb/ForumBreadcrumbBuilderBase.php
+++ b/core/modules/forum/src/Breadcrumb/ForumBreadcrumbBuilderBase.php
@@ -68,6 +68,8 @@
    *   The forum manager service.
    * @param \Drupal\Core\StringTranslation\TranslationInterface $string_translation
    *   The string translation service.
+   * @param \Drupal\Core\Entity\EntityRepositoryInterface $entity_repository
+   *   The entity repository service.
    */
   public function __construct(EntityTypeManagerInterface $entity_type_manager, ConfigFactoryInterface $config_factory, ForumManagerInterface $forum_manager, TranslationInterface $string_translation, EntityRepositoryInterface $entity_repository) {
     $this->entityTypeManager = $entity_type_manager;
diff -u b/core/modules/forum/tests/src/Unit/Breadcrumb/ForumListingBreadcrumbBuilderTest.php b/core/modules/forum/tests/src/Unit/Breadcrumb/ForumListingBreadcrumbBuilderTest.php
--- b/core/modules/forum/tests/src/Unit/Breadcrumb/ForumListingBreadcrumbBuilderTest.php
+++ b/core/modules/forum/tests/src/Unit/Breadcrumb/ForumListingBreadcrumbBuilderTest.php
@@ -53,13 +53,12 @@
     $entity_repository = $this->createMock('Drupal\Core\Entity\EntityRepositoryInterface');
 
     // Make an object to test.
-    $builder = new ForumListingBreadcrumbBuilder($entity_type_manager, $config_factory, $forum_manager, $translation_manager);
+    $builder = new ForumListingBreadcrumbBuilder($entity_type_manager, $config_factory, $forum_manager, $translation_manager, $entity_repository);
 
     $route_match = $this->createMock('Drupal\Core\Routing\RouteMatchInterface');
     $route_match->expects($this->once())
         $forum_manager,
         $translation_manager,
-        $entity_repository,
       ])
       ->setMethods(NULL)
       ->getMock();
@@ -81,6 +80,10 @@
       ->disableOriginalConstructor()
       ->getMock();
 
+    $prophecy = $this->prophesize('Drupal\Core\Language\Language');
+    $prophecy->getId()->willReturn('en');
+    $language = $prophecy->reveal();
+
     return [
       [
         FALSE,
@@ -89,10 +92,6 @@
       ->disableOriginalConstructor()
       ->getMock();
 
-    $prophecy = $this->prophesize('Drupal\Core\Language\Language');
-    $prophecy->getId()->willReturn('en');
-    $language = $prophecy->reveal();
-
     return [
       [
         FALSE,
diff -u b/core/modules/forum/tests/src/Unit/Breadcrumb/ForumNodeBreadcrumbBuilderTest.php b/core/modules/forum/tests/src/Unit/Breadcrumb/ForumNodeBreadcrumbBuilderTest.php
--- b/core/modules/forum/tests/src/Unit/Breadcrumb/ForumNodeBreadcrumbBuilderTest.php
+++ b/core/modules/forum/tests/src/Unit/Breadcrumb/ForumNodeBreadcrumbBuilderTest.php
@@ -58,14 +58,13 @@
     $entity_repository = $this->createMock('Drupal\Core\Entity\EntityRepositoryInterface');
 
     // Make an object to test.
-    $builder = new ForumNodeBreadcrumbBuilder($entity_type_manager, $config_factory, $forum_manager, $translation_manager);
+    $builder = new ForumNodeBreadcrumbBuilder($entity_type_manager, $config_factory, $forum_manager, $translation_manager, $entity_repository);
 
     $route_match = $this->createMock('Drupal\Core\Routing\RouteMatchInterface');
     $route_match->expects($this->once())
           $config_factory,
           $forum_manager,
           $translation_manager,
-          $entity_repository,
         ]
       )
       ->setMethods(NULL)