Drupal-code being called from CiviCRM

On ~line 622 of CRM/Core/BAO/Navigation.php, something that looks like:

($config->userSystem->is_drupal) &&
((module_exists('toolbar') && user_access('access toolbar')) ||
module_exists('admin_menu') && user_access('access administration menu')
)

This is obviously bad for lots of reasons. CiviCRM should basically never call into Drupal. In my case, it's attempting to call functions that no longer exist in Drupal 8.