protection for superclass

[Jari-Matti Mäkelä]

Sean Kelly wrote:
> Frank Benoit wrote:
>> If I do this
>>
>> class T : private D {
>> }
>>
>> the functionality from Object is no more visible to a user of T.
>> e.g. container can complain, they cannot access opEqual. Is this the
>> wanted behaviour?
> 
> I'd say it is, as in some cases this might actually be desirable.  The
> class could still be compared as an Object:
> 
> Object o = new T;
> Object p = o;
> 
> assert( o == p );
> 

Well, this might be true in C++, where you can limit the visibility of
superclass members in derived classes. AFAIK, in Java public inheritance
is the only way to do it:

 class derived extends base { } [Java] is actually
 class derived : public base { } [C++]

Now what if [D code here]

 interface I { void foo() {} }
 class Base : I { }
 class Derived : private Base { }

 Derived abc = new Derived();
 Base cba = abc;
 I bar = cba;

Then abc.foo() would be illegal, but both cba.foo() and bar.foo() would
be correct. Sounds _somewhat_ confusing to me.

-- 
Jari-Matti