BUG #5793: tsquery error

The following bug has been logged online:

Bug reference:      5793
Logged by:
Email address:      ms@instytut.com.pl
PostgreSQL version: 8, 9
Operating system:   Linux
Description:        tsquery error
Details:

The expression 'a & !(c) | a & b' is interpreted as '( a | !c ) & a & b'.
select 'a & !(c) | a & b'::tsquery;

Subsequent "rewrites" of the same expression give inconsistent results:

select '(a & !(c | d)) | (a & b)'::tsquery; -> 'a & !(c | d) | a & b'
(correct)
select 'a & !(c | d) | a & b'::tsquery; -> '(a | !(c | d)) & a & b' (not
correct)