eccube-3.0.16をみると、このファイルのここで作ってるみたいです。
new \Twig_SimpleFunction('form_widget',・・・って箇所かと思います。
eccube-3.0.16\vendor\symfony\twig-bridge\Extension\FormExtension.php
PHP
123
4public function getFunctions()
5{
6 return array(
7 new \Twig_SimpleFunction('form_enctype', null, array('node_class' => 'Symfony\Bridge\Twig\Node\FormEnctypeNode', 'is_safe' => array('html'), 'deprecated' => true, 'alternative' => 'form_start')),
8 new \Twig_SimpleFunction('form_widget', null, array('node_class' => 'Symfony\Bridge\Twig\Node\SearchAndRenderBlockNode', 'is_safe' => array('html'))),
9 new \Twig_SimpleFunction('form_errors', null, array('node_class' => 'Symfony\Bridge\Twig\Node\SearchAndRenderBlockNode', 'is_safe' => array('html'))),
10 new \Twig_SimpleFunction('form_label', null, array('node_class' => 'Symfony\Bridge\Twig\Node\SearchAndRenderBlockNode', 'is_safe' => array('html'))),
11 new \Twig_SimpleFunction('form_row', null, array('node_class' => 'Symfony\Bridge\Twig\Node\SearchAndRenderBlockNode', 'is_safe' => array('html'))),
12 new \Twig_SimpleFunction('form_rest', null, array('node_class' => 'Symfony\Bridge\Twig\Node\SearchAndRenderBlockNode', 'is_safe' => array('html'))),
13 new \Twig_SimpleFunction('form', null, array('node_class' => 'Symfony\Bridge\Twig\Node\RenderBlockNode', 'is_safe' => array('html'))),
14 new \Twig_SimpleFunction('form_start', null, array('node_class' => 'Symfony\Bridge\Twig\Node\RenderBlockNode', 'is_safe' => array('html'))),
15 new \Twig_SimpleFunction('form_end', null, array('node_class' => 'Symfony\Bridge\Twig\Node\RenderBlockNode', 'is_safe' => array('html'))),
16 new \Twig_SimpleFunction('csrf_token', array($this, 'renderCsrfToken')),
17 );
18}