$softMapper not defined in Ajax checkDupes

I just observed that in CRM_Contact_Page_AJAX::getDedupes $sortMapper must throw an enotice (picked up in IDE not on site but it is not defined & appears to be a copy & paste error)

$sort = isset($_REQUEST['iSortCol_0']) ? $sortMapper[CRM_Utils_Type::escape($_REQUEST['iSortCol_0'], 'Integer')] : 'sort_name';