Description:
------------
A callable can be defined as an array containing class and method.

Calling call_user_func() with such an array has no issue.
If you try to use the array as a callable, then 'self' loose its special meaning and an error is triggered saying class self does not exists.

Test script:
---------------
<?php

class CallBySelf
{
    public static function foo()
    {
        echo 'Foo', PHP_EOL;
    }
    
    public static function testCall()
    {
        $method = ['self', 'foo'];
        var_dump(is_callable($method));
        
        echo 'Call via call_user_func: ';
        call_user_func($method);
        
        echo 'Direct call: ';
        $method();
    }
}

CallBySelf::testCall();

Expected result:
----------------
Call via call_user_func: Foo
Direct call: Foo


Actual result:
--------------
bool(true)
Call via call_user_func: Foo
Direct call: 
Fatal error: Class 'self' not found in /in/Ssgep on line 19