diff --git a/core/lib/Drupal/Core/Validation/ConstraintManager.php b/core/lib/Drupal/Core/Validation/ConstraintManager.php
index d2e84c7..da1ddc6 100644
--- a/core/lib/Drupal/Core/Validation/ConstraintManager.php
+++ b/core/lib/Drupal/Core/Validation/ConstraintManager.php
@@ -47,7 +47,7 @@ class ConstraintManager extends DefaultPluginManager {
    *   The module handler to invoke the alter hook with.
    */
   public function __construct(\Traversable $namespaces, CacheBackendInterface $cache_backend, LanguageManager $language_manager, ModuleHandlerInterface $module_handler) {
-    parent::__construct('Plugin/Validation/Constraint', $namespaces);
+    parent::__construct('Plugin/Validation/Constraint', $namespaces, 'Drupal\Core\Validation\Annotation\Constraint');
     $this->discovery = new StaticDiscoveryDecorator($this->discovery, array($this, 'registerDefinitions'));
     $this->alterInfo($module_handler, 'validation_constraint');
     $this->setCacheBackend($cache_backend, $language_manager, 'validation_constraint_plugins');