Failure using static class attribute as class name

[danog]

Code:

<?php

class a { public static $fun = 'a'; }

$a = new a::$fun();

Result:

[daniil@daniil-arch jav]$ jppm start
-> linux
-> app:run 
-> install 

Fatal error: Uncaught ParseError: Syntax error, unexpected ')' in res://4.php on line 6, position 17
Stack Trace:
#0 {main}
  thrown in res://4.php on line 6