FormTestValidateRequiredNoTitleForm.php

<?php

declare (strict_types=1);
namespace Drupal\form_test\Form;

use Drupal\Core\Form\FormBase;
use Drupal\Core\Form\FormStateInterface;

/**
 * Form constructor to test the #required property without #title.
 *
 * @internal
 */
class FormTestValidateRequiredNoTitleForm extends FormBase {
  
  /**
   * {@inheritdoc}
   */
  public function getFormId() {
    return 'form_test_validate_required_form_no_title';
  }
  
  /**
   * {@inheritdoc}
   */
  public function buildForm(array $form, FormStateInterface $form_state) {
    $form['textfield'] = [
      '#type' => 'textfield',
      '#required' => TRUE,
    ];
    $form['actions'] = [
      '#type' => 'actions',
    ];
    $form['actions']['submit'] = [
      '#type' => 'submit',
      '#value' => 'Submit',
    ];
    return $form;
  }
  
  /**
   * {@inheritdoc}
   */
  public function submitForm(array &$form, FormStateInterface $form_state) {
    $this->messenger()
      ->addStatus('The form_test_validate_required_form_no_title form was submitted successfully.');
  }

}