Drupal Twig extension breaks the twig debug node printer

Problem/Motivation

Twig has a wonderful AST debug printer which is broken with Drupal.

Steps to reproduce

$twig = \Drupal::service('twig');
$string = '{{ foo }}';
$stream = $twig->tokenize(new \Twig\Source($string, '{# inline_template_start #}'));
$nodes = $twig->parse($stream);
$twig->compile($nodes);
print $nodes;

errors out with var_export does not handle circular references Node.php:56

I believe I have hunted the problem to the class resolver https://gist.github.com/chx/df272b847b2770be00f6b7b8bf1b5ff8 but it's not yet clear what are the next steps. To be continued tomorrow.

Proposed resolution

Note adding DependencySerializationTrait to TwigExtension does not help -- especially because ClassResolver already has it. Yet, the problem lies somewhere there. Hiding the container from the eyes of var_export does help, ContainerAwareTrait could store https://gist.github.com/chx/6a0388e79b527b6bbcea6956f5225821 instead of the raw container. This is, of course, extremely ugly. To be continued tomorrow.

Remaining tasks

User interface changes

API changes

Data model changes

Release notes snippet