diff --git a/core/lib/Drupal/Core/Entity/Plugin/Validation/Constraint/CompositeConstraintBase.php b/core/lib/Drupal/Core/Entity/Plugin/Validation/Constraint/CompositeConstraintBase.php
new file mode 100644
index 0000000..43936a5
--- /dev/null
+++ b/core/lib/Drupal/Core/Entity/Plugin/Validation/Constraint/CompositeConstraintBase.php
@@ -0,0 +1,34 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Core\Entity\Plugin\Validation\Constraint\CompositeConstraintBase.
+ */
+
+namespace Drupal\Core\Entity\Plugin\Validation\Constraint;
+
+use Symfony\Component\Validator\Constraint;
+
+/**
+ * Provides a base class for constraints validating multiple fields.
+ *
+ * The constraint must be defined on entity-level; i.e., added to the entity
+ * type.
+ *
+ * With that the $values in CompositeConstraintValidatorBase::doValidate() will
+ * return an array keyed with 'name', 'uid' and 'entity', with 'entity' being
+ * the actual full entity.
+ *
+ * @see \Drupal\Core\Entity\EntityType::addConstraint
+ */
+abstract class CompositeConstraintBase extends Constraint {
+
+  /**
+   * An array of entity fields which should be passed to the validator.
+   *
+   * @return string[]
+   *   An array of field names.
+   */
+  abstract public function coversFields();
+
+}
diff --git a/core/modules/comment/src/Entity/Comment.php b/core/modules/comment/src/Entity/Comment.php
index f83f54b..ba539f9 100644
--- a/core/modules/comment/src/Entity/Comment.php
+++ b/core/modules/comment/src/Entity/Comment.php
@@ -258,7 +258,7 @@ public static function baseFieldDefinitions(EntityTypeInterface $entity_type) {
       ->setTranslatable(TRUE)
       ->setSetting('max_length', 60)
       ->setDefaultValue('')
-      ->addConstraint('CommentName', array());
+      ->addConstraint('CommentName');
 
     $fields['mail'] = BaseFieldDefinition::create('email')
       ->setLabel(t('Email'))
diff --git a/core/modules/comment/src/Plugin/Validation/Constraint/CommentNameConstraint.php b/core/modules/comment/src/Plugin/Validation/Constraint/CommentNameConstraint.php
index d387542..15611e1 100644
--- a/core/modules/comment/src/Plugin/Validation/Constraint/CommentNameConstraint.php
+++ b/core/modules/comment/src/Plugin/Validation/Constraint/CommentNameConstraint.php
@@ -7,7 +7,7 @@
 
 namespace Drupal\comment\Plugin\Validation\Constraint;
 
-use Symfony\Component\Validator\Constraint;
+use Drupal\Core\Entity\Plugin\Validation\Constraint\CompositeConstraintBase;
 
 /**
  * Supports validating comment author names.
@@ -17,7 +17,7 @@
  *   label = @Translation("Comment author name", context = "Validation")
  * )
  */
-class CommentNameConstraint extends Constraint {
+class CommentNameConstraint extends CompositeConstraintBase {
 
   /**
    * Message shown when an anonymous user comments using a registered name.
@@ -40,4 +40,11 @@ class CommentNameConstraint extends Constraint {
    */
   public $messageMatch = 'The specified author name does not match the comment author.';
 
+  /**
+   * {@inheritdoc}
+   */
+  public function coversFields() {
+    return ['name', 'uid'];
+  }
+
 }
diff --git a/core/modules/comment/src/Plugin/Validation/Constraint/CommentNameConstraintValidator.php b/core/modules/comment/src/Plugin/Validation/Constraint/CommentNameConstraintValidator.php
index f6397e0..8d52479 100644
--- a/core/modules/comment/src/Plugin/Validation/Constraint/CommentNameConstraintValidator.php
+++ b/core/modules/comment/src/Plugin/Validation/Constraint/CommentNameConstraintValidator.php
@@ -8,6 +8,7 @@
 namespace Drupal\comment\Plugin\Validation\Constraint;
 
 use Drupal\Core\DependencyInjection\ContainerInjectionInterface;
+use Drupal\Core\Entity\Plugin\Validation\Constraint\CompositeConstraintValidatorBase;
 use Drupal\user\UserStorageInterface;
 use Symfony\Component\DependencyInjection\ContainerInterface;
 use Drupal\comment\CommentInterface;
@@ -46,40 +47,35 @@ public static function create(ContainerInterface $container) {
   /**
    * {@inheritdoc}
    */
-  public function validate($items, Constraint $constraint) {
-    /** @var CommentNameConstraint $constraint */
-    if (!isset($items)) {
+  public function validate($value, Constraint $constraint) {
+    if (!isset($value)) {
       return;
     }
-    /** @var CommentInterface $comment */
-    $comment = $items->getEntity();
 
-    if (!isset($comment)) {
-      // Looks like we are validating a field not being part of a comment,
-      // nothing we can do then.
-      return;
-    }
-    $author_name = $items->first()->value;
+    $entity = $value->getEntity();
+
+    $author_name = $entity->name->value;
+    $owner_id = (int) $entity->uid->target_id;
 
     // Do not allow unauthenticated comment authors to use a name that is
     // taken by a registered user.
-    if (isset($author_name) && $author_name !== '' && $comment->getOwnerId() === 0) {
+    if (isset($author_name) && $author_name !== '' && $owner_id === 0) {
       $users = $this->userStorage->loadByProperties(array('name' => $author_name));
       if (!empty($users)) {
         $this->context->addViolation($constraint->messageNameTaken, array('%name' => $author_name));
       }
     }
     // If an author name and owner are given, make sure they match.
-    elseif (isset($author_name) && $author_name !== '' && $comment->getOwnerId()) {
-      $owner = $comment->getOwner();
+    elseif (isset($author_name) && $author_name !== '' && $owner_id) {
+      $owner = $this->userStorage->load($owner_id);
       if ($owner->getUsername() != $author_name) {
         $this->context->addViolation($constraint->messageMatch);
       }
     }
 
     // Anonymous account might be required - depending on field settings.
-    if ($comment->getOwnerId() === 0 && empty($author_name) &&
-      $this->getAnonymousContactDetailsSetting($comment) === COMMENT_ANONYMOUS_MUST_CONTACT) {
+    if ($owner_id === 0 && empty($author_name) &&
+      $this->getAnonymousContactDetailsSetting($entity) === COMMENT_ANONYMOUS_MUST_CONTACT) {
       $this->context->addViolation($constraint->messageRequired);
     }
   }
diff --git a/core/modules/system/src/Tests/Entity/FieldWidgetConstraintValidatorTest.php b/core/modules/system/src/Tests/Entity/FieldWidgetConstraintValidatorTest.php
index 4a56198..1be9696 100644
--- a/core/modules/system/src/Tests/Entity/FieldWidgetConstraintValidatorTest.php
+++ b/core/modules/system/src/Tests/Entity/FieldWidgetConstraintValidatorTest.php
@@ -37,7 +37,7 @@ protected function setUp() {
    */
   public function testValidation() {
     $entity_type = 'entity_test_constraint_violation';
-    $entity = entity_create($entity_type, array('id' => 1, 'revision_id' => 1));
+    $entity = entity_create($entity_type, array('id' => 1, 'revision_id' => 1, 'name' => 'test', 'type' => 'test2'));
     $display = entity_get_form_display($entity_type, $entity_type, 'default');
     $form = array();
     $form_state = new FormState();
@@ -55,6 +55,7 @@ public function testValidation() {
 
     $errors = $form_state->getErrors();
     $this->assertEqual($errors['name'], 'Widget constraint has failed.', 'Constraint violation is generated correctly');
+    $this->assertEqual($errors['type'], 'Multiple fields are validated', 'Constraint violation is generated correctly');
   }
 
 }
diff --git a/core/modules/system/tests/modules/entity_test/src/Entity/EntityTestConstraintViolation.php b/core/modules/system/tests/modules/entity_test/src/Entity/EntityTestConstraintViolation.php
index 48b27ab..9d83bed 100644
--- a/core/modules/system/tests/modules/entity_test/src/Entity/EntityTestConstraintViolation.php
+++ b/core/modules/system/tests/modules/entity_test/src/Entity/EntityTestConstraintViolation.php
@@ -44,6 +44,13 @@ public static function baseFieldDefinitions(EntityTypeInterface $entity_type) {
     ));
     $fields['name']->addConstraint('FieldWidgetConstraint', array());
 
+    $fields['type']->setDisplayOptions('form', array(
+      'type' => 'string',
+      'weight' => 0,
+    ));
+
+    $fields['type']->addConstraint('EntityTestCompositeConstraint', array());
+
     return $fields;
   }
 
diff --git a/core/modules/system/tests/modules/entity_test/src/Plugin/Validation/Constraint/EntityTestCompositeConstraint.php b/core/modules/system/tests/modules/entity_test/src/Plugin/Validation/Constraint/EntityTestCompositeConstraint.php
new file mode 100644
index 0000000..8e6c4d5
--- /dev/null
+++ b/core/modules/system/tests/modules/entity_test/src/Plugin/Validation/Constraint/EntityTestCompositeConstraint.php
@@ -0,0 +1,31 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\entity_test\Plugin\Validation\Constraint\EntityTestCompositeConstraint.
+ */
+
+namespace Drupal\entity_test\Plugin\Validation\Constraint;
+
+use Drupal\Core\Entity\Plugin\Validation\Constraint\CompositeConstraintBase;
+
+/**
+ * Constraint with multiple fields.
+ *
+ * @Plugin(
+ *   id = "EntityTestCompositeConstraint",
+ *   label = @Translation("Constraint with multiple fields.")
+ * )
+ */
+class EntityTestCompositeConstraint extends CompositeConstraintBase {
+
+  public $message = 'Multiple fields are validated';
+
+  /**
+   * {@inheritdoc}
+   */
+  public function coversFields() {
+    return ['name', 'type'];
+  }
+
+}
diff --git a/core/modules/system/tests/modules/entity_test/src/Plugin/Validation/Constraint/EntityTestCompositeConstraintValidator.php b/core/modules/system/tests/modules/entity_test/src/Plugin/Validation/Constraint/EntityTestCompositeConstraintValidator.php
new file mode 100644
index 0000000..7c3dcee
--- /dev/null
+++ b/core/modules/system/tests/modules/entity_test/src/Plugin/Validation/Constraint/EntityTestCompositeConstraintValidator.php
@@ -0,0 +1,31 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\entity_test\Plugin\Validation\Constraint\EntityTestCompositeConstraintValidator.
+ */
+
+namespace Drupal\entity_test\Plugin\Validation\Constraint;
+
+use Symfony\Component\Validator\Constraint;
+use Symfony\Component\Validator\ConstraintValidator;
+
+class EntityTestCompositeConstraintValidator extends ConstraintValidator {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function validate($value, Constraint $constraint) {
+    if (!isset($value)) {
+      return;
+    }
+
+    $entity = $value->getEntity();
+
+    if ($entity->name->value === 'test' && $entity->type->value === 'test2') {
+      $this->context->addViolation($constraint->message);
+    }
+
+  }
+
+}