All menus under 'Reports' gives php warning stating
Warning: Illegal offset type in CRM_Report_Form_Instance::buildForm() (line 138 of /Users/vasanthakaje/Sites/devdesktop/drupal819/libraries/civicrm/CRM/Report/Form/Instance.php). => Array
In Drupal 7 $user_roles_array used to be an array with values as
[integer => 'string']
In Drupal 8, $user_roles_array is changed to an array with values as
['string' => array]
Hence trying to store value using $value (thinking it is a string) is causing issue. Changed it to $key and it works fine.