Description:
------------
As we have "late static bindings" now, would it be reasonable to have a "abstract static property"?

See the bellow example.

abstract class A {
    //If this could be declared as abstract to make 
    //the subclass have to redeclare it in order to
    //have it own $mTest to use.
    //If $mTest is not declared in one subclass, it would
    //change the $mTest of A which is shared by many 
    //subclasses, some unexpected things would happen.
    //The design is to make each subclass have its own
    //$mTest to use and it has to be existed.
    //$mTest in A is just for a skeleton purpose, even should
    //not be assigned a value.
    static $mTest;

    static function setTest($value) {
        static::$mTest = $value;
    }

    static function DumpTest () {
        echo 'static:' . static::$mTest . "\n";
        echo 'A-self:' . self::$mTest . "\n";
    }
}

class B extends A {
    static function DumpTest () {
        parent::DumpTest();
        echo 'B-self:' . self::$mTest . "\n";
        echo 'B-parent:' . parent::$mTest . "\n";
    }
}

class C extends A {
    static $mTest;
    static function DumpTest () {
        parent::DumpTest();
        echo 'C-self:' . self::$mTest . "\n";
        echo 'C-parent:' . parent::$mTest . "\n";
    }
}

class D extends C {
    static $mTest;
    static function DumpTest () {
        parent::DumpTest();
        echo 'D-self:' . self::$mTest . "\n";
        echo 'D-parent:' . parent::$mTest . "\n";
    }
}

B::setTest('test1');//This will change the $mStorages of class A
B::DumpTest();
//static:test1
//A-self:test1
//B-self:test1
//B-parent:test1
C::setTest('test2');
C::DumpTest();
//static:test2
//A-self:test1
//C-self:test2
//C-parent:test1
D::setTest('test3');
D::DumpTest();
static:test3
//A-self:test1
//C-self:test2
//C-parent:test1
//D-self:test3
//D-parent:test2