title: Symfony ExceptionHandler throwing an error about itself
body: <p>I'm working on an upgrade of an application to use Symfony 3 and PHP 7. I keep getting this error. I'm not sure where it stems from or how to fix it.</p>
  
  <blockquote>
    <p>Symfony\Component\Debug\ExceptionHandler::handle() must be an instance of Exception</p>
  </blockquote>