Require optional linking error

[Paul Sandoz]

On Aug 9, 2012, at 3:01 PM, Alan Bateman <Alan.Bateman at oracle.com> wrote
> There are anomalies with the current implementation that arise due to order.

Yep.


> In this case I think it should be an error due to the conflict (which I think is what you are saying too).

Yes.


> One could argue that it could succeed with z just not linked to y but that might be problematic if something in z were to meet up with a type from y at runtime.
> 

Exactly, errors would be pushed to compiler or even worse the runtime making it hard to diagnose the underlying cause.

Paul.