BUG #14300: Empty cube representation

The following bug has been logged on the website:

Bug reference: 14300
Logged by: Alexander Ustimenko
Email address: a(at)ustimen(dot)co
PostgreSQL version: 9.5.4
Operating system: Debian 4.9.2-10 64-bit
Description:

ACTUAL:

SELECT CUBE(ARRAY[]::INTEGER[]);
-- Gives '()'

SELECT '()'::CUBE;
-- Gives 'ERROR: bad cube representation'

SHOULD BE?:

SELECT CUBE(ARRAY[]::INTEGER[]);
-- Should give some 'ERROR: bad cube representation' ?

QUESTION:

Does cube type wrong or cube parser wrong?