Validator/Constraints/ExpressionValidator.php
public function validate($value, Constraint $constraint)
    {
        if (null === $value) {
            return;
        }

        if (!$constraint->type) {
            throw new ConstraintDefinitionException('"type" must be specified on constraint Expression');
        }

        if(!$this->registry->has($constraint->type)) {
            return;
        }

        $this->context->getValidator()
            ->inContext($this->context)
            ->validate($value, $this->registry->get($constraint->type));
    }
public function validate($value, Constraint $constraint)
    {
        if (null === $value) {
            return;
        }

        if (!$constraint->type) {
            throw new ConstraintDefinitionException('"type" must be specified on constraint Expression');
        }

        if(!$this->registry->has($constraint->type)) {
            return;
        }

        $this->context->getValidator()
            ->inContext($this->context)
            ->validate($value, $this->registry->get($constraint->type));
    }
{@inheritdoc}