The warning is correct.
It is not correct - the use statement has effect, as documented in manual http://php.net/manual/en/language.namespaces.importing.php.
The manual is wrong. Importing global object is use \ArrayObject - note the \.
From the look of it it seems like the page there has all \'s in the code skipped (compare comments to the code). Could somebody from the docs team please fix it?
--
Stanislav Malyshev, Zend Software Architect
stas@zend.com http://www.zend.com/
(408)253-8829 MSN: stas@zend.com