diff --git a/src/Symfony/Component/Validator/Test/ConstraintValidatorTestCase.php b/src/Symfony/Component/Validator/Test/ConstraintValidatorTestCase.php
index ea07316ac6..3d1fc81c9a 100644
--- a/src/Symfony/Component/Validator/Test/ConstraintValidatorTestCase.php
+++ b/src/Symfony/Component/Validator/Test/ConstraintValidatorTestCase.php
@@ -341,6 +341,9 @@ class ConstraintViolationAssertion
     }
 }
 
+/**
+ * @internal
+ */
 class AssertingContextualValidator implements ContextualValidatorInterface
 {
     private $expectNoValidate = false;