BUG #8230: Time interval size overflow

The following bug has been logged on the website:

Bug reference: 8230
Logged by: Rok Kralj
Email address: rok(dot)kralj(at)gmail(dot)com
PostgreSQL version: 9.2.4
Operating system: Arch Linux
Description:

As far as I know, the INTERVAL type is represented using three int32, one
for months, days and milliseconds.

However, overflow detections seems to work correctly only on these three
types; if they get overflown indirectly, they do not get detected:

SELECT INTERVAL '3000000000 days'
ERROR: interval field value out of range: "3000000000 days"

SELECT INTERVAL '2000000000 years'
-147483648 years

I'm surprised this hasn't been reported yet. The expected behaviour is to
raise an error.