diff -u b/core/lib/Drupal/Core/Block/BlockBase.php b/core/lib/Drupal/Core/Block/BlockBase.php
--- b/core/lib/Drupal/Core/Block/BlockBase.php
+++ b/core/lib/Drupal/Core/Block/BlockBase.php
@@ -21,6 +21,7 @@
 use Drupal\Core\Language\Language;
 use Drupal\Core\Cache\Cache;
 use Drupal\Core\Session\AccountInterface;
+use Drupal\Component\Transliteration\TransliterationInterface;
 
 /**
  * Defines a base block implementation that most blocks plugins will extend.
@@ -440,6 +441,16 @@
   }
 
   /**
+   * Sets the transliteration service.
+   *
+   * @param \Drupal\Component\Transliteration\TransliterationInterface $transliteration
+   *   The transliteration service.
+   */
+  public function setTransliteration(TransliterationInterface $transliteration) {
+    $this->transliteration = $transliteration;
+  }
+
+  /**
    * Returns the cache contexts required for this block.
    *
    * @return array
@@ -552,3 +563,2 @@
   }
-
 }
reverted:
--- b/core/modules/block/tests/modules/block_test/src/Plugin/Block/TestBlockInstantiation.php
+++ a/core/modules/block/tests/modules/block_test/src/Plugin/Block/TestBlockInstantiation.php
@@ -10,7 +10,6 @@
 use Drupal\Core\Block\BlockBase;
 use Drupal\Core\Form\FormStateInterface;
 use Drupal\Core\Session\AccountInterface;
-use Drupal\Component\Transliteration\TransliterationInterface;
 
 /**
  * Provides a basic block for testing block instantiation and configuration.
@@ -66,16 +65,4 @@
     );
   }
 
-  /**
-   * Sets the transliteration service.
-   *
-   * @param \Drupal\Component\Transliteration\TransliterationInterface $transliteration
-   *   The transliteration service.
-   *
-   * @return $this
-   */
-  public function setTransliteration(TransliterationInterface $transliteration) {
-    $this->transliteration = $transliteration;
-    return $this;
-  }
 }