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