title: Symfony 2: How do I check if a user is not logged in inside a template?
body: <p>In Symfony 2 templates (using Twig), how can I effectively check whether a user is not logged in?</p>
  
  <p>I don't want to use <code>ROLE</code> checks. I want a straightforward way to check if a user is not logged in.</p>
  
  <p>I'm aware that comparing <code>app.user.username</code> with <code>anon</code> works, but that just doesn't feel right to me.</p>