Jak zobrazovat chybové hlášky v šabloně? (Nette 3.0)

Ahoj všem,

seznamuji se s Nette 3.0 a tvořím přihlašování uživatelů s ověřováním v databázi. Vycházím ze Sandboxu https://github.com/nette/sandbox Mám problém s tím, jak zobrazovat v šabloně chybové hlášky, uložené přes $form->addError. Pokud přidám do šablony toto:

<ul class="errors" n:if="$form->hasErrors()">
        <li n:foreach="$form->errors as $error">{$error}</li>
</ul>

zahlásí mi to Undefined variable: form. Poradíte mi, prosím, kde dělám chybu? Děkuji předem za informace.

App\Config\common.neon

parameters:

php:
	date.timezone: Europe/Prague

application:
	errorPresenter: Error
	mapping:
		*: App\*Module\Presenters\*Presenter

session:
	expiration: 14 days
	autoStart: true

services:
	- App\Model\UserModel
	- App\Forms\FormFactory
	- App\Forms\PrihlaseniFormFactory
	router: App\Router\RouterFactory::createRouter

App\Forms\FormFactory.php

<?php

declare(strict_types=1);

namespace App\Forms;

use Nette;
use Nette\Application\UI\Form;


final class FormFactory
{
	use Nette\SmartObject;
	public function create(): Form
	{
		$form = new Form;
		return $form;
	}
}
?>

App\Forms\PrihlaseniFormFactory.php

<?php

declare(strict_types=1);

namespace App\Forms;

use Nette;
use Nette\Application\UI\Form;
use Nette\Security\User;


final class PrihlaseniFormFactory
{
	use Nette\SmartObject;

	/** @var FormFactory */
	private $factory;

	/** @var User */
	private $user;


	public function __construct(FormFactory $factory, User $user)
	{
		$this->factory = $factory;
		$this->user = $user;
	}

	public function create(callable $onSuccess): Form
	{
		$form = $this->factory->create();
		$form->addText('inputEmail', 'E-mail:')
			->setRequired('Zadejte e-mailovou adresu.')
			->setHtmlAttribute('placeholder', 'E-mail');
		$form->addPassword('inputPassword', 'Heslo:')
			->setRequired('Zadejte heslo.')
			->setHtmlAttribute('placeholder', 'Heslo');
		$form->addSubmit('buttonLogin', 'Přihlásit');

		$form->onSuccess[] = function (Form $form, \stdClass $values) use ($onSuccess): void {
			try {
				$this->user->login($values->inputEmail, $values->inputPassword);
			} catch (\Nette\Security\AuthenticationException $e) {
				$form->addError('Neplatné uživatelské jméno nebo heslo.');
				return;
			}
			$onSuccess();
		};

		return $form;
	}
}
?>

App\Model\UserModel.php

<?php

declare(strict_types=1);

namespace App\Model;

use Nette;
use Nette\Security\Passwords;

final class UserModel implements Nette\Security\IAuthenticator
{
	use Nette\SmartObject;

	private const
	TABLE_NAME = 'bm_users',
	COLUMN_ID = 'id',
	COLUMN_ACTIVE = 'active',
	COLUMN_NAME = 'username',
	COLUMN_PASSWORD_HASH = 'password',
	COLUMN_ROLE = 'role';

	/** @var Nette\Database\Context */
	private $database;

	/** @var Passwords */
	private $passwords;

	public function __construct(Nette\Database\Context $database, Passwords $passwords)
	{
		$this->database = $database;
		$this->passwords = $passwords;
	}

	/**
	* Performs an authentication.
	* @throws Nette\Security\AuthenticationException
	*/
	public function authenticate(array $credentials): Nette\Security\IIdentity
	{
		[$username, $password] = $credentials;

		$row = $this->database->table(self::TABLE_NAME)
		->where(self::COLUMN_NAME, $username)
		->fetch();

		$row = $this->database->table(self::TABLE_NAME)
				->where(self::COLUMN_NAME, $username)
				->fetch();
		if(!$row)
		{
			throw new Nette\Security\AuthenticationException('The username is incorrect.', self::IDENTITY_NOT_FOUND);
		}
		elseif(!$this->passwords->verify($password, $row[self::COLUMN_PASSWORD_HASH]))
		{
			throw new Nette\Security\AuthenticationException('Heslo není správné!', self::INVALID_CREDENTIAL);
		}
		elseif($row[self::COLUMN_ACTIVE] == 1)
		{
			throw new Nette\Security\AuthenticationException('Uživatelský účet není aktivní!', self::NOT_APPROVED);
		}
		elseif($this->passwords->NeedsRehash($row[self::COLUMN_PASSWORD_HASH]))
		{
			$row->update(array(self::COLUMN_PASSWORD_HASH => $this->passwords->hash($password)));
		}
		$arr = $row->toArray();
		unset($arr[self::COLUMN_PASSWORD_HASH]);
		return new Nette\Security\Identity($row[self::COLUMN_ID], $row[self::COLUMN_ROLE], $arr);
	}

}
?>

App\Presenters\templates\Components\Forms.latte

{define form-1 $formName}
	<div n:foreach="$flashes as $flash" class="alert {$flash->type} alert-dismissible fade show" role="alert">
		{$flash->message|noescape}
		<button type="button" class="close" data-dismiss="alert" aria-label="Close">
			<span aria-hidden="true">&times;</span>
		</button>
	</div>

	<form n:name=$formName class=form-horizontal>
		<div class="form-group mb-2">
			{input inputEmail class => 'form-control form-control-sm'}
		</div>
		<div class="form-group mb-2">
			{input inputPassword class => 'form-control form-control-sm'}
		</div>
		<div class="text-left">
			{input buttonLogin class => 'btn btn-sm btn-success mb-0 font-weight-bold'}
			<a n:href="Prihlaseni:novyUcet" class="btn btn-sm btn-danger mb-0 float-right"><strong>Nový účetet</strong></a>
		</div>
		<div class="clearfix text-center mt-2">
			<a n:href="Prihlaseni:obnoveniHesla" class="fsize-3">Nepamatuji si heslo</a>
		</div>
	</form>
{/define}

App\Presenters\templates\@layout.latte

{import 'Components/Forms.latte'}
<!DOCTYPE html>
<html lang="cs-cz">
.
.
.
</html>

App\Presenters\templates\Homepage\default.latte

{block title}{/block}
{block description}{/block}
{block keywords}{/block}
{block content}

{include form-1 prihlaseniForm}

{/block}

App\Presenters\BasePresenter.php

<?php

declare(strict_types=1);

namespace App\Presenters;

use Nette;
use Nette\Application\UI\Form;
use App\Forms;


abstract class BasePresenter extends Nette\Application\UI\Presenter
{
	/** @persistent */
	public $backlink = '';

	/** @var Forms\PrihlaseniFormFactory */
	private $prihlaseniFactory;


	public function __construct(Forms\PrihlaseniFormFactory $prihlaseniFactory)
	{
		$this->prihlaseniFactory = $prihlaseniFactory;

	}

	/**
	 * Prihlaseni form factory.
	 */
	protected function createComponentPrihlaseniForm(): Form
	{
		return $this->prihlaseniFactory->create(function (): void {
			$this->redirect('Homepage:');
		});
	}

	public function actionOdhlaseni(): void
	{
		$this->getUser()->logout();
	}
}
?>