Final by default?

[Walter Bright]

On 3/12/2014 11:44 PM, Manu wrote:
> But you understand the danger in creating a situation where experts can't
> optimise their code even if they want to; if at some later time it becomes an
> issue, or some new customer comes along with more stringent requirements.
> These are not unrealistic hypothetical scenarios. Libraries exist, and they have
> customers by definition. Requirements change over time. Defaulting to an
> inflexible position is dangerous.

As I pointed out in another post, virtuality is hardly the only thing that can 
change in an interface that strongly affects performance. The existence of 
destructors is another. About everything about an interface affects performance.