Symfony crashes when using provider

[jsgoupil]

When using a provider, Symfony 2.2 crashes

{% highlight 'php' ['geshi'] %}
test
{% endhighlight %}

outputs this:

ob_start();        // line 41
echo "            test
";
$context['source_321381366344038'] = new Twig_Markup(ob_get_clean(), $this->env->getCharset());
$context['language_321381366344038'] = $this->getAttribute("php", "geshi", array(), "array"); // CRASHES HERE
$context['provider_321381366344038'] = null;

The error is:

Impossible to access a key ("geshi") on a "string" variable in ...twig

[jsgoupil]

The workaround is to not put the provider inside an array like.
So
{% highlight 'php' 'geshi' %} works