Limited member function templates?

[Nathan Reed]

Yigal Chripun wrote:
> I may be mistaken, but isn't it enough to use the following:
> ----
> interface Collection (T) {
>    void addAll(T) (Collection!(T) toAdd);
> }
> ----
> a bicycle should conform to a is-a relationship
> (a bicycle is a vehicle). so you can in fact add them all due to 
> inheritance. or am I missing something here?

Unfortunately that doesn't quite work.  Even if a bicycle is-a vehicle, 
it doesn't follow that a collection of bicycles is-a collection of 
vehicles.  Consider that you can add a car to a collection of vehicles, 
but it would be an error to add a car to a collection of bicycles.

Thanks,
Nathan Reed