interface reference not compatible to Object?

[Frank Benoit (keinfarbton)]

>> Is this the intended behaviour? If *every* object in D is a Object, then
>> every interface reference refers to an Object also. This said, the above
>> should compile?

And as already said in #d : I wonder why this even compiles. Why is C
not enforced to "reimplement" the methods from IObject?

Wouldn't it be consistent if the compiler implicitly inherit all
interfaces without a super-interface from this IObject?