Attempting to alias keywords results in a cryptic Parse error

[Girgias]

Description

This issue is most notable with the array keyword as it is also a built-in type name.

Indeed trying to alias int:

<?php

use int as I;

Parses just fine (however it is impossible to actually use I as a type declaration as you would get the following error Fatal error: Cannot use 'int' as class name as it is reserved in /in/nNOgL on line 5 (see https://3v4l.org/nNOgL) which is its own mess that we might want to catch early)

However, with array (https://3v4l.org/fWrTK):

<?php

use array as a;

We get the following error message:

Parse error: syntax error, unexpected token "array" in /in/F6SlE on line 3

I don't even know if this is actually fixable as this seems like some parser shenanigans.

PHP Version

PHP 8.0.22 - master

Operating System

No response

[olleharstedt]

Also the list keyword...

[cmb69]

PHP distinguishes between keywords and reserved words (array is a keyword; int is a reserved word). That should explain the reported behavior.

Since it doesn't make sense to alias non class-ish names, and the keyword/reserved word distinction is already documented, I'm closing this ticket.