symfony/symfony-docs — pull request #2051 by vmelnik-ukraine (2012-12-19 20:15:08+00:00)
Title: fixed namespace in form.type_extension code example

Hello. If file hosts in src/Acme/MainBundle/Form/Type/MyFormTypeExtension.php, namespace must be a Acme\MainBundle\Form\Type, not a Acme\MainBundle\Form\Type\MyFormTypeExtension

reference / dic_tags.rst