This one's a killer to explain.  The following code should print 1; instead it prints 0.  This is apparently caused by too many inherited instances of A, with one reference to the object getting one indexed pointer and the other object getting the other for whatever reason.  So when the equivalency operator attempts to align the two instances, it gets two different pointers and bails.

    interface A
    {
        void call (A other);
    }

    interface Ab : A
    {
    }

    class B : A
    {
        void call (A other)
        {
            printf ("%d\n", this === other);
        }
    }

    class C : B, Ab
    {
    }

    void main ()
    {
        C b = new C ();

        b.call (b);
    }

I can work around the problem.

Yeah... I've already posted about this one.  It's in DStress.  See "=== No Damn Good"

Burton Radons wrote:
> This one's a killer to explain.  The following code should print 1; instead it prints 0.  This is apparently caused by too many inherited instances of A, with one reference to the object getting one indexed pointer and the other object getting the other for whatever reason.  So when the equivalency operator attempts to align the two instances, it gets two different pointers and bails.
> 
>     interface A
>     {
>         void call (A other);
>     }
> 
>     interface Ab : A
>     {
>     }
> 
>     class B : A
>     {
>         void call (A other)
>         {
>             printf ("%d\n", this === other);
>         }
>     }
> 
>     class C : B, Ab
>     {
>     }
> 
>     void main ()
>     {
>         C b = new C ();
> 
>         b.call (b);
>     }
> 
> I can work around the problem.