reverted:
--- b/core/modules/hal/tests/src/Functional/EntityResource/Node/NodeHalJsonCookieTranslationsTest.php
+++ /dev/null
@@ -1,198 +0,0 @@
-<?php
-
-namespace Drupal\Tests\hal\Functional\EntityResource\Node;
-
-use Drupal\Component\Utility\NestedArray;
-use Drupal\Core\Cache\Cache;
-use Drupal\language\Entity\ConfigurableLanguage;
-use Drupal\language\Entity\ContentLanguageSettings;
-use Drupal\Tests\hal\Functional\EntityResource\HalEntityNormalizationTrait;
-use Drupal\user\Entity\User;
-use GuzzleHttp\RequestOptions;
-
-/**
- * @group hal
- */
-class NodeHalJsonCookieTranslationsTest extends NodeHalJsonCookieTest {
-
-  use HalEntityNormalizationTrait;
-
-  /**
-   * {@inheritdoc}
-   */
-  public static $modules = ['hal', 'content_translation'];
-
-  /**
-   * {@inheritdoc}
-   */
-  protected static $format = 'hal_json';
-
-  /**
-   * {@inheritdoc}
-   */
-  protected static $mimeType = 'application/hal+json';
-
-  /**
-   * {@inheritdoc}
-   */
-  protected static $patchProtectedFieldNames = [
-    'changed',
-    'revision_timestamp',
-    'revision_uid',
-  ];
-
-  /**
-   * {@inheritdoc}
-   */
-  protected function getExpectedCacheContexts() {
-    return Cache::mergeContexts(
-      parent::getExpectedCacheContexts(),
-      ['languages:language_content', 'languages:language_interface']
-    );
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  protected function setUpAuthorization($method) {
-    parent::setUpAuthorization($method);
-    $this->grantPermissionsToTestedRole(['translate any entity', 'administer nodes']);
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  protected function createEntity() {
-    if (!ConfigurableLanguage::load('de')) {
-      ConfigurableLanguage::createFromLangcode('de')->save();
-    }
-
-    /** @var \Drupal\node\NodeInterface $node */
-    $node = parent::createEntity();
-
-    ContentLanguageSettings::loadByEntityTypeBundle('node', 'camelids')
-      ->setLanguageAlterable(TRUE)
-      ->setDefaultLangcode('en')
-      ->save();
-
-    $translation = $node->addTranslation('de', $node->toArray());
-    $translation->get('title')->value = 'Lama';
-    $node->save();
-    return $node;
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  protected function getExpectedNormalizedEntity() {
-    $normalization = parent::getExpectedNormalizedEntity();
-
-    foreach ($this->entity->getFieldDefinitions() as $field_name => $field_definition) {
-      // @todo It seems that currently two items exist if the *storage* is
-      //   translatable, should be when the field is?
-      if ($field_definition->getFieldStorageDefinition()->isTranslatable() && isset($normalization[$field_name])) {
-        $normalization[$field_name][1] = [
-          'lang' => 'de',
-        ] + $normalization[$field_name][0];
-      }
-    }
-
-    $normalization['title'][1]['value'] = 'Lama';
-    $normalization['langcode'][1]['value'] = 'de';
-    $normalization['default_langcode'][1]['value'] = '0';
-
-    $author = User::load($this->entity->getOwnerId());
-    $normalization['_links'][$this->baseUrl . '/rest/relation/node/camelids/uid'][1] = [
-      'href' => $this->baseUrl . '/user/' . $author->id() . '?_format=hal_json',
-      'lang' => 'de',
-    ];
-    $normalization['_embedded'][$this->baseUrl . '/rest/relation/node/camelids/uid'][1] = [
-      '_links' => [
-        'self' => [
-          'href' => $this->baseUrl . '/user/' . $author->id() . '?_format=hal_json',
-        ],
-        'type' => [
-          'href' => $this->baseUrl . '/rest/type/user/user',
-        ],
-      ],
-      'uuid' => [
-        ['value' => $author->uuid()]
-      ],
-      'lang' => 'de',
-    ];
-
-    return $normalization;
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function testPost() {
-    parent::testPost();
-
-    // Create an entity with a translation.
-    $normalized_entity = $this->getExpectedNormalizedEntity();
-    unset($normalized_entity['nid']);
-    unset($normalized_entity['vid']);
-    unset($normalized_entity['uuid']);
-    unset($normalized_entity['changed']);
-    unset($normalized_entity['revision_timestamp']);
-    unset($normalized_entity['_embedded'][$this->baseUrl . '/rest/relation/node/camelids/revision_uid']);
-    $entity_body_with_a_translations = $this->serializer->encode($normalized_entity, static::$format);
-
-    $request_options = [];
-    $request_options[RequestOptions::HEADERS]['Content-Type'] = static::$mimeType;
-    $request_options[RequestOptions::BODY] = $entity_body_with_a_translations;
-    $request_options = NestedArray::mergeDeep($request_options, $this->getAuthenticationRequestOptions('POST'));
-
-    $url = $this->getPostUrl();
-    $url->setOption('query', ['_format' => static::$format]);
-
-    // 201 for well-formed request.
-    $response = $this->request('POST', $url, $request_options);
-    $this->assertResourceResponse(201, FALSE, $response);
-    /** @var \Drupal\node\NodeInterface $created_node */
-    $created_node = $this->serializer->deserialize((string) $response->getBody(), get_class($this->entity), static::$format);
-    $this->assertSame([$created_node->toUrl('canonical')->setAbsolute(TRUE)->toString()], $response->getHeader('Location'));
-    $this->assertFalse($response->hasHeader('X-Drupal-Cache'));
-
-    $this->assertSame('Llama', $created_node->getTitle());
-    $this->assertSame('Lama', $created_node->getTranslation('de')->getTitle());
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function testPatch() {
-    parent::testPatch();
-
-    $title_with_translation = $this->getNormalizedPatchEntity();
-    $title_with_translation['title'][0]['lang'] = 'en';
-    $title_with_translation['title'][1] = [
-      'value' => 'Drama-Lama',
-      'lang' => 'de',
-    ];
-
-    $entity_body_title_with_translation = $this->serializer->encode($title_with_translation, static::$format);
-
-    $request_options = [];
-    $request_options[RequestOptions::HEADERS]['Content-Type'] = static::$mimeType;
-    $request_options[RequestOptions::BODY] = $entity_body_title_with_translation;
-    $request_options = NestedArray::mergeDeep($request_options, $this->getAuthenticationRequestOptions('POST'));
-
-    $url = $this->getUrl();
-    $url->setOption('query', ['_format' => static::$format]);
-
-    $response = $this->request('PATCH', $url, $request_options);
-    $this->assertResourceResponse(200, FALSE, $response);
-    $this->assertFalse($response->hasHeader('X-Drupal-Cache'));
-
-    $storage = \Drupal::entityTypeManager()->getStorage('node');
-    $storage->resetCache();
-
-    $patched_node = $storage->load($this->entity->id());
-    $this->assertSame('Dramallama', $patched_node->getTitle());
-    $this->assertSame('Drama-Lama', $patched_node->getTranslation('de')->getTitle());
-  }
-
-}
diff -u b/core/modules/rest/src/Plugin/rest/resource/EntityResourceValidationTrait.php b/core/modules/rest/src/Plugin/rest/resource/EntityResourceValidationTrait.php
--- b/core/modules/rest/src/Plugin/rest/resource/EntityResourceValidationTrait.php
+++ b/core/modules/rest/src/Plugin/rest/resource/EntityResourceValidationTrait.php
@@ -13,7 +13,7 @@
  */
 trait EntityResourceValidationTrait {
 
-  /**->getTranslation($langcode)
+  /**
    * Verifies that the whole entity does not violate any validation constraints.
    *
    * @param \Drupal\Core\Entity\ContentEntityInterface $entity