BUG #6242: ERROR: unexpected CASE WHEN clause: 333

The following bug has been logged online:

Bug reference:      6242
Logged by:          Sergey
Email address:      sergey-1987@yandex.ru
PostgreSQL version: 8.4.4
Operating system:   FreeBSD 8.1-RELEASE
Description:        ERROR: unexpected CASE WHEN clause: 333
Details:

create view test_view as
select
    case n when null then 1 when 1 then 2 when 2 then 3 end
from (
    values (null), (1), (2)
) as t(n)

pg_dump then fail with error: "ERROR: unexpected CASE WHEN clause: 333" but
select * from test_view does not.

This error occurs with the configuration "transform_null_equals".