These days we're updating the Symfony Demo app to use the new service configuration proposed for Symfony 3.3. See https://github.com/symfony/symfony-demo/pull/483/files

One of the things I like the least is this config:

services:
    AppBundle\Twig\AppExtension:
        $locales: '%app_locales%'

    AppBundle\EventListener\RedirectToPreferredLocaleSubscriber:
        $locales: '%app_locales%'

    AppBundle\EventListener\CommentNotificationSubscriber:
        $sender: '%app.notifications.email_sender%'

Having to create that boring config just to pass some container parameters destroys the purpose of this new config being RAD, etc.

Proposal

Would it make any sense to "autowire the parameters"?

Before

class AppExtension extends \Twig_Extension
{
    // ...

    public function __construct(Markdown $parser, $locales)
    {
        // ...
    }

    // ...
}

services:
    AppBundle\Twig\AppExtension:
        $locales: '%app_locales%'

After

class AppExtension extends \Twig_Extension
{
    // ...

    public function __construct(Markdown $parser, $locales = '%app_locales%')
    {
        // ...
    }

    // ...
}