BUG #1518: Conversions to (undocumented) SQL year-month and day-time interval types silently discard data

The following bug has been logged online:

Bug reference:      1518
Logged by:          Roy Badami
Email address:      roy@gnomon.org.uk
PostgreSQL version: 8.0.1
Operating system:   Solaris 9
Description:        Conversions to (undocumented) SQL year-month and
day-time interval types silently discard data
Details:

Conversions to the (undocumented) SQL year-month and day-time intervals
silently discard data, instead of raising an exception.

Note, the following examples intentinally use non-standard interval syntax,
since SQL standard interval syntax appears to be broken...

radius=# create table foo (year_month interval year to month);
CREATE TABLE
radius=# insert into foo values ('1 year 1 month');
INSERT 19963 1
radius=# select * from foo;
  year_month
--------------
 1 year 1 mon
(1 row)

-- correct

radius=# insert into foo values ('1 hour 1 minute');
INSERT 19964 1

-- should be an error, I think?

radius=# select * from foo;
  year_month
--------------
 1 year 1 mon
 00:00:00
(2 rows)

-- but instead the interval has been replaced by a zero interval

radius=# create table bar (day_time interval day to second);
CREATE TABLE
radius=# insert into bar values ('1 hour 1 minute');
INSERT 19968 1
radius=# select * from bar;
 day_time
----------
 01:01:00
(1 row)

-- correct

radius=# insert into bar values ('1 year 1 month');
INSERT 19969 1

-- should be an error, I think?

radius=# select * from bar;
 day_time
----------
 01:01:00
 00:00:00
(2 rows)

-- but instead has been converted to a zero interval