Update to Drupal 8.2.6. For more information, see https://www.drupal.org/project/drupal/releases/8.2.6

vendor/symfony/validator/Context/ExecutionContext.php

@@ -27,8 +27,6 @@ use Symfony\Component\Validator\Violation\ConstraintViolationBuilder;
 /**
  * The context used and created by {@link ExecutionContextFactory}.
  *
- * @since  2.5
- *
  * @author Bernhard Schussek <bschussek@gmail.com>
  *
  * @see ExecutionContextInterface
@@ -289,6 +287,11 @@ class ExecutionContext implements ExecutionContextInterface
         return $this->group;
     }
 
+    public function getConstraint()
+    {
+        return $this->constraint;
+    }
+
     /**
      * {@inheritdoc}
      */