Twig i18n : Unexpected tag name “trans”

Question

I'm trying to do some i18n on some Twig templates. The relevant code in index.php is as follows :

// Twig
$app->register(new Silex\Provider\TwigServiceProvider(), array(
    'twig.path' => __DIR__ . '/../src/views',
));
$twig = new \Twig_Environment($app['twig.loader.filesystem']);
$twig->addExtension(new \Twig_Extensions_Extension_I18n());

// User Controller Service Provider for SimpleUser
$app->register($u = new SimpleUser\UserServiceProvider());
$app['twig.loader.filesystem']->addPath(__DIR__.'/../src/views/user','user');
$app['user.controller']->setLayoutTemplate('layout.twig');
$app->mount('/silex-ror/user', $u);

Then, in the twig template being rendered I wrote :

<h1>{% trans %}List users{% endtrans %}</h1>

But I get an error :

Unexpected tag name "trans"

Since I don't get any error when adding the extension, I assume it's simply being completely ignored when I try to render the template, but I'm not sure where I'm making a mistake.

Any help appreciated.

Answer 1

Register the Translation Provider before:

$app->register(new Silex\Provider\TranslationServiceProvider(), array(
  'locale_fallbacks' => array('en'),
));

and then register Twig:

$app->register(new Silex\Provider\TwigServiceProvider(), array(
  'twig.path' => __DIR__ . '/../src/views',
));

there is no need to register the Twig i18n extension!

See also Silex TranslationServiceProvider