Symfony密码重置无FOS捆绑包

我正在尝试制作一个用户可以轻松更改密码的表单。我希望我的逻辑是正确的，但是我得到了如下错误；

Expected argument of type "string", "AppBundle'Form'ChangePasswordType" given

这是我的控制器；

public function changePasswdAction(Request $request)
{
    $changePasswordModel = new ChangePassword();
    $form = $this->createForm(new ChangePasswordType(), $changePasswordModel);
    $form->handleRequest($request);
    if ($form->isSubmitted() && $form->isValid()) {
        // perform some action,
        // such as encoding with MessageDigestPasswordEncoder and persist
        return $this->redirect($this->generateUrl('homepage'));
    }
    return $this->render(':security:changepassword.html.twig', array(
        'form' => $form->createView(),
    ));
}

这是我的模型；

class ChangePassword
{
/**
 * @SecurityAssert'UserPassword(
 *     message = "Wrong value for your current password"
 * )
 */
protected $oldPassword;
/**
 * @Assert'Length(
 *     min = 6,
 *     minMessage = "Password should by at least 6 chars long"
 * )
 */
protected $newPassword;
/**
 * @return mixed
 */
public function getOldPassword()
{
    return $this->oldPassword;
}
/**
 * @param mixed $oldPassword
 */
public function setOldPassword($oldPassword)
{
    $this->oldPassword = $oldPassword;
}
/**
 * @return mixed
 */
public function getNewPassword()
{
    return $this->newPassword;
}
/**
 * @param mixed $newPassword
 */
public function setNewPassword($newPassword)
{
    $this->newPassword = $newPassword;
}   

}

这是我的更改密码类型；

use Symfony'Component'Form'AbstractType;
use Symfony'Component'Form'FormBuilderInterface;
use Symfony'Component'OptionsResolver'OptionsResolver;
class ChangePasswordType extends AbstractType
{
    public function buildForm(FormBuilderInterface $builder, array $options)
    {
        $builder->add('oldPassword', 'password');
        $builder->add('newPassword', 'repeated', array(
            'type' => 'password',
            'invalid_message' => 'The password fields must match.',
            'required' => true,
            'first_options'  => array('label' => 'Password'),
            'second_options' => array('label' => 'Repeat Password'),
        ));
    }
}

这是我的观众；

{{ form_widget(form.current_password) }}
{{ form_widget(form.plainPassword.first) }}
{{ form_widget(form.plainPassword.second) }}

@dragste提到的解决方案对我来说效果很好。我更改了

$form = $this->createForm(new ChangePasswordType(), $changePasswordModel);

用这条线；

$form = $this->createForm(ChangePasswordType::class, $changePasswordModel);