UPGRADE FROM 2.5 to 2.6
=======================

Validator
---------

 * The internal method `setConstraint()` was added to
   `Symfony\Component\Validator\Context\ExecutionContextInterface`. With
   this method, the context is informed about the constraint that is currently
   being validated.

   If you implement this interface, make sure to add the method to your
   implementation. The easiest solution is to just implement an empty method:

   ```php
   public function setConstraint(Constraint $constraint)
   {
   }
   ```