Cannot login when userfield is id

[stevepiercy]

Use this sample code. For some reason, authentication fails whenever the userfield is set to id, but it will work when the userfield is any other column.

$db -> settable('user')
$s_user -> userfield = 'id'
$s_user -> login(-username=$s_id, -password=($f -> getvalue('password')))
$s_auth_id = integer($s_user -> id_user)

$out -> append($db -> action_statement)
$out -> append('<br>')
$out -> append($db -> found_count)
$out -> append('<br>')
$out -> append($s_user -> auth)
$out -> append('<br>')
$out -> append($s_user -> id_user)