BUG #3695: Pgsql does not report non existing function

The following bug has been logged online:

Bug reference: 3695
Logged by: Roger
Email address: ramoloney(at)hotmail(dot)com
PostgreSQL version: 8.3
Operating system: Windows
Description: Pgsql does not report non existing function
Details:

I've looked at 8.3 on windows and I'm using 8.2.5 actively for a large
company project on linux.

I have a big problem with Postgres not reporting functions that do not
exist. It makes developing on large projects very very awkward.

For example, if I have a pgsql function which makes a call to
x := DAY(timestamp);

This is not reported. It does not exist. Likewise, if I had a function
MyFunc which does exist which requires 3 parameters, the following also are
not reported:

x := myfunc();
x := myfunc(p1)
x := myfunc(p2);

Sureley, the plgsql parser SHOULD report this. It occurs frequently when
porting to postgres from existing database systems.

Am I missing some switch that I can turn on ?
Thanks in advance.