added failing test for derived class

[exeba]

When a derived class redeclares a private member of the base class, the
"Exporter" class fails to recognize that.

[exeba]

sebastianbergmann/exporter#35 will make tests pass

[sebastianbergmann]

Even with sebastianbergmann/exporter#35, I do not understand what it is you are trying to report.

[exeba]

class Base 
{
    private $privateField;
    
    public function __construct($value)
    {
        $this->privateField = $value;
    }

}

class Derived extends Base 
{
    private $privateField;

    public function __construct($value, $parentValue)
    {
        parent::__consturct($parentValue);
        $this->privateField = $value;
    }
}

$object1 = new Derived(10, 200);
$object2 = new Derived(100, 200);

The two objects should be considered different, but since Derived declares a private field that already exists in Base, the field by field comparison considers only the $privateField in the Base class, ingoring the one in Derived.