If I create a new empty file, save it as test.js, and type doc, the code completion dialog automatically displays document along with a short description of the interface and a link to the MDN Web APIs page.

However, if I create a new empty file, save it as test.php and type <?php followed by the name of a standard PHP function or class (e.g. DateTime), the code completion dialog doesn't display.

More specifically, typing array displays the word completion options array and array_key_exists, but no documentation of the interface to array_key_exists() (i.e. details from the PHP manual).

I am running Arch Linux and I have tried both the AUR package and manually building from source. It seems to apply to versions 10 and above.