Inconsistent behavior on Array & Is Null?

Joe,

First off, pardon me if these are known things which are already fixed in CVS.
Also, let me again thank you for all the work on Arrays in 7.4; I've been
able to tremendously simplify quite a number of procedures in my databases
thanks to the new array support.

Now, the issue:
I'm noticing some inconsistent behavior regarding empty arrays and IS NULL
status. For example:

net_test=# select array_upper('{}'::INT[], 1);
array_upper
-------------

(1 row)

net_test=# select array_upper('{}'::INT[], 1) IS NULL;
?column?
----------
t
(1 row)

net_test=# select '{}'::INT[] IS NULL;
?column?
----------
f
(1 row)

I feel that this is confusing; an empty array should be considered NULL
everywhere or nowhere. For that matter, the new array declaration syntax
does not support empty arrays:

net_test=# select ARRAY[ ]::INT[];
ERROR: syntax error at or near "]" at character 15
net_test=# select ARRAY[]::INT[];
ERROR: syntax error at or near "]" at character 14
net_test=#

--
-Josh Berkus
Aglio Database Solutions
San Francisco