^^&&^^

Edit File: ConstantTest.php

<?php

/*
 * This file is part of Twig.
 *
 * (c) Fabien Potencier
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

namespace Twig\Node\Expression\Test;

use Twig\Compiler;
use Twig\Node\Expression\TestExpression;

/**
 * Checks if a variable is the exact same value as a constant.
 *
 *    {% if post.status is constant('Post::PUBLISHED') %}
 *      the status attribute is exactly the same as Post::PUBLISHED
 *    {% endif %}
 *
 * @author Fabien Potencier <fabien@symfony.com>
 */
class ConstantTest extends TestExpression
{
    public function compile(Compiler $compiler)
    {
        $compiler
            ->raw('(')
            ->subcompile($this->getNode('node'))
            ->raw(' === constant(')
        ;

if ($this->getNode('arguments')->hasNode(1)) {
            $compiler
                ->raw('get_class(')
                ->subcompile($this->getNode('arguments')->getNode(1))
                ->raw(')."::".')
            ;
        }

$compiler
            ->subcompile($this->getNode('arguments')->getNode(0))
            ->raw('))')
        ;
    }
}

class_alias('Twig\Node\Expression\Test\ConstantTest', 'Twig_Node_Expression_Test_Constant');