src/Tomahawk/Templating/Twig/Bridge/TwigEngine.php
public function exists($name)
    {
        if ($name instanceof \Twig_Template) {
            return true;
        }

        $loader = $this->environment->getLoader();

        if ($loader instanceof \Twig_ExistsLoaderInterface || method_exists($loader, 'exists')) {
            return $loader->exists((string) $name);
        }

        try {
            // cast possible TemplateReferenceInterface to string because the
            // EngineInterface supports them but Twig_LoaderInterface does not
            $loader->getSourceContext((string) $name)->getCode();
        } catch (\Twig_Error_Loader $e) {
            return false;
        }

        return true;
    }
public function exists($name)
    {
        if ($name instanceof \Twig_Template) {
            return true;
        }

        $loader = $this->environment->getLoader();

        if ($loader instanceof \Twig_ExistsLoaderInterface || method_exists($loader, 'exists')) {
            return $loader->exists((string) $name);
        }

        try {
            // cast possible TemplateReferenceInterface to string because the
            // EngineInterface supports them but Twig_LoaderInterface does not
            $loader->getSourceContext((string) $name)->getCode();
        } catch (\Twig_Error_Loader $e) {
            return false;
        }

        return true;
    }
{@inheritdoc}

It also supports \Twig_Template as name parameter.