How do I get an array of user roles to use in #options? Trying to convert my module to D8 and running into a problem using the D7: user_roles() function. Here's my D7 module code:

$form['role_vis_settings']['tynt_roles'] = array(
  '#type'          =&gt; 'checkboxes',
  '#title'         =&gt; t('Add tracking for specific roles'),
  '#default_value' =&gt; variable_get('tynt_roles', array()),
  '#options'       =&gt; user_roles(),
  '#description'   =&gt; t('Add tracking only for the selected role(s). If none of the roles are selected, all users will be tracked. If a user has any of the roles checked, that user will be tracked.'),
);


And what I've got so far for D8:

$form['role_vis_settings']['tynt_roles'] = array(
  '#type'          =&gt; 'checkboxes',
  '#title'         =&gt; $this-&gt;t('Add tracking for specific roles'),
  '#default_value' =&gt; $settings['tynt_roles'],
  '#options'       =&gt; user_roles(),
  '#description'   =&gt; $this-&gt;t('Add tracking only for the selected role(s). If none of the roles are selected, all users will be tracked. If a user has any of the roles checked, that user will be tracked.'),
);


But get:

The website encountered an unexpected error. Please try again later.


I've looked at:


https://api.drupal.org/api/drupal/core!modules!user!src!Entity!User.php/function/User%3A%3AgetRoles/8
https://api.drupal.org/api/drupal/core!modules!user!user.module/function/user_roles/8


The second was closet but not a format the #options array would allow (https://api.drupal.org/api/drupal/developer!topics!forms_api_reference.html/8#options).

Anyone have any ideas?
The correct function name is:

user_role_names()