title: The configuration key is unsupported for definition "parameters"
body: <p>I'm using Symfony DI component. I'm trying to pass string parameter into service constructor as follows:</p>
  
  <pre><code>services:
     parameters:
          config.directory: './../../../'
     _defaults:
          public: true
     settings:
          class: Bar\Foo\Service
          arguments: ['%config.directory%']
  </code></pre>
  
  <p>I'm compiling container by:</p>
  
  <pre><code>$containerBuilder = new ContainerBuilder();
  $loader = new YamlFileLoader($containerBuilder, new FileLocator($dir));
  $loader-&gt;load('services.yaml');
  $containerBuilder-&gt;compile();
  </code></pre>
  
  <p>Exception:</p>
  
  <blockquote>
    <p>Fatal error: Uncaught
    Symfony\Component\DependencyInjection\Exception\InvalidArgumentException:
    The configuration key "config.directory" is unsupported for definition
    "parameters"</p>
  </blockquote>