[Form] Calling setDefault for data class does not associates form with binded class

[Koc]

public function buildForm(FormBuilderInterface $builder, array $options)
{
    $builder->add('firstName');
}

// form type not associated with User, no ctrl+click on "firstName"
$resolver->setDefault('data_class', User::class);

// works ok
$resolver->setDefaults(['data_class' => User::class]);

[Haehnchen]

done