diff --git a/core/lib/Drupal/Core/Entity/EntityTypeRepository.php b/core/lib/Drupal/Core/Entity/EntityTypeRepository.php
index d89b75e3ffce9c4db8293d27cc100205fbcd13a9..f63965a8b341e0900bdd56da523c91dd70e9e82f 100644
--- a/core/lib/Drupal/Core/Entity/EntityTypeRepository.php
+++ b/core/lib/Drupal/Core/Entity/EntityTypeRepository.php
@@ -102,6 +102,7 @@ public function getEntityTypeFromClass($class_name) {
    * {@inheritdoc}
    */
   public function clearCachedDefinitions() {
+    @trigger_error(__METHOD__ . ' is deprecated in drupal:8.0.0 and is removed in drupal:9.0.0', E_USER_DEPRECATED);
     $this->classNameEntityTypeMap = [];
   }
 
diff --git a/core/lib/Drupal/Core/Entity/EntityTypeRepositoryInterface.php b/core/lib/Drupal/Core/Entity/EntityTypeRepositoryInterface.php
index 5bb2c8dcab73587168b48497e262a339d0a4a68e..7ab7736462065eca484f4a8558f1433d0d8fae1e 100644
--- a/core/lib/Drupal/Core/Entity/EntityTypeRepositoryInterface.php
+++ b/core/lib/Drupal/Core/Entity/EntityTypeRepositoryInterface.php
@@ -45,9 +45,7 @@ public function getEntityTypeFromClass($class_name);
   /**
    * Clear the static cache.
    *
-   * @deprecated in Drupal 8.0.0, will be removed before Drupal 9.0.0.
-   *
-   * @todo Remove in https://www.drupal.org/node/2549143.
+   * @deprecated in drupal:8.0.0 and is removed in drupal:9.0.0.
    */
   public function clearCachedDefinitions();
 
diff --git a/core/modules/system/tests/src/Functional/Entity/Traits/EntityDefinitionTestTrait.php b/core/modules/system/tests/src/Functional/Entity/Traits/EntityDefinitionTestTrait.php
index 00148b466baba5117159af0eb2a0d532be83b08a..175a8106983457b2ea9d038de7ea9476bba0139d 100644
--- a/core/modules/system/tests/src/Functional/Entity/Traits/EntityDefinitionTestTrait.php
+++ b/core/modules/system/tests/src/Functional/Entity/Traits/EntityDefinitionTestTrait.php
@@ -456,7 +456,6 @@ protected function getUpdatedEntityTypeDefinition($revisionable = FALSE, $transl
     $this->container->get('entity_type.manager')->clearCachedDefinitions();
     $this->container->get('entity_type.bundle.info')->clearCachedBundles();
     $this->container->get('entity_field.manager')->clearCachedFieldDefinitions();
-    $this->container->get('entity_type.repository')->clearCachedDefinitions();
 
     return $entity_type;
   }