PHP variable class static method call

I have a property that stores a class name as a string. I then want to use this to call a static method of said class. As far as I know, this is possible since PHP 5.3. I am running 5.6.x on a vagrant box.

I want to do this:

$item = $this->className::getItem($id);

But I get the following error:

Parse error: syntax error, unexpected '::' (T_PAAMAYIM_NEKUDOTAYIM)...

The following works fine:

$c = $this->className;
$item = $c::getItem($id);

Any idea why? Is this not the same thing?

Answer

The problem is that you are access are property from a class in the first useage, but then in the second try you are parsing the value of the class property (into $c), what is a classname as string, and this can used for static calls to static class functions. The first try, trys to access the static method on an string (the class property).

class a {
     static function b(){echo'works';}
}
$a='a';
$a::b();

But the real issue of the error is, that this ->FooBar:: is an syntax error in PHP.