Edit File: ExtensionSet.php
<?php use Twig\ExtensionSet; class_exists('Twig\ExtensionSet'); @trigger_error(sprintf('Using the "Twig_ExtensionSet" class is deprecated since Twig version 2.7, use "Twig\ExtensionSet" instead.'), E_USER_DEPRECATED); if (\false) { /** @deprecated since Twig 2.7, use "Twig\ExtensionSet" instead */ class Twig_ExtensionSet extends ExtensionSet { } }