operator does not exist

Hello,

we updated one of our systems from postgresql 8.2 to 8.3 and now some
queries are generating errors that no operator matches the given name
and argument type. That is not surprising as in v8.3 the automatic
casting was removed what troubles me is that sometimes it still casts

select '1' = 1 results in true

while select sum(msg_price) from messages where msg_itemid = 0 results
in error:
ERROR:  operator does not exist: character varying = integer
LINE 1: select sum(msg_price) from messages where msg_itemid = 0

I will add the operator ant then we'll fix the queries, but is the first
example ok? Should it not raise error ?

--
Julius Tuskenis
Programavimo skyriaus vadovas
UAB nSoft
mob. +37068233050