Add \Drupal\system\Entity\Menu::toString()

The error text is seen in the AJAX response and has no stack trace and is similar in the php error log:
"The website encountered an unexpected error. Try again later.

Exception: Object of type Drupal\system\Entity\Menu cannot be printed. in Drupal\Core\Template\TwigExtension->escapeFilter() (line 459 of core/lib/Drupal/Core/Template/TwigExtension.php)."

Reproduce: It occurs in the module tb_megamenu using module nd_visualshortcodes which at some point includes a template with the twig processing. Some code would be needed to mock this up - but the core code: (core/lib/Drupal/Core/Template/TwigExtension.php) expects there to be a toRenderable() or __toString() or toString() method on any Object that's passed - so why not just add it? (see patch file)

The main module is https://www.drupal.org/project/tb_megamenu

nd_visualshortcodes is a custom module - part of a theme package.

The menu is in a block and when edited looks like the attached image (menu_issue.png). You click the edit icon in the + Menu strip to get the problem.

Hopefully all Entities will have a toString() method if there is any chance they will be used in Twig templates. Maybe a change the interface or the Twig filter to add a method to get the Entity metadata ('configuration entity class')?
eg in core/modules/system/src/Entity/Menu.php

* @ConfigEntityType(
 *   id = "menu",
 *   label = @Translation("Menu"),
...

👍

@cilefen the background is explained above - but if you really want a stack trace just pass a Menu entity to a twig template and you'll get one, eg In a controller:

use Drupal\system\Entity\Menu;
....
$m = new Menu(['id'=>'mymenuid', 'label'=>'mymenulabel'], 'menu');
$renderable = [
   '#theme' => 'my_template',
   '#test_var' => $m,
];
return  \Drupal::service('renderer')->renderPlain($renderable);