Symfony3 "The option "placeholder" does not exist."
<p>I want to create a user settings panel.</p>

<p>In the form I would like to have a placeholder with the current value the user has for his param.</p>

<p>Here is a sample code:</p>

<pre><code>//...

$form = $this-&gt;createFormBuilder($user)
            -&gt;add('Username', TextType::class, array(
                'label' =&gt; "Change UserName",
                'placeholder' =&gt; $userData[0]-&gt;getUsername()
            ))
//...
</code></pre>

<p>Using such values I get this error in the browser:</p>

<blockquote>
  <p>The option "placeholder" does not exist. Defined options are:
  "action", "allow_extra_fields", "attr", "auto_initialize",
  "block_name", "by_reference", "compound", "constraints",
  "csrf_field_name", "csrf_message", "csrf_protection", "csrf_token_id",
  "csrf_token_manager", "data", "data_class", "disabled", "empty_data",
  "error_bubbling", "error_mapping", "extra_fields_message",
  "inherit_data", "invalid_message", "invalid_message_parameters",
  "label", "label_attr", "label_format", "mapped", "method",
  "post_max_size_message", "property_path", "required",
  "translation_domain", "trim", "upload_max_size_message",
  "validation_groups".</p>
</blockquote>

<p>The problem is only with the parameter itself because <code>'data' =&gt; $userData[0]-&gt;getUsername()</code> works and displays the correct information.</p>

<p>Here are the use parameters of my page:</p>

<pre><code>namespace AppBundle\Controller;

use Sensio\Bundle\FrameworkExtraBundle\Configuration\Route;
use AppBundle\Entity\Task;
use Symfony\Bundle\FrameworkBundle\Controller\Controller;
use Symfony\Component\Form\Extension\Core\Type\TextareaType;
use Symfony\Component\HttpFoundation\Request;
use Symfony\Component\Form\Extension\Core\Type\TextType;
use Symfony\Component\Form\Extension\Core\Type\SubmitType;
use AppBundle\Entity\Post;
use AppBundle\Entity\User; 
</code></pre>