Why are opEquals/opCmp arguments not in or const for Objects?

[Stewart Gordon]

On 19/03/2013 00:19, Jakob Ovrum wrote:
<snip>
> It's worth noting that including a standard interface (as in the
> interface keyword) for stuff like Comparable, Hashable etc. is a
> possibility that can be explored to enable runtime polymorphism akin to
> the current Object for programs that need it. Either way, I'm glad it's
> on its way out of Object.

Can you think a use case that can't be fulfilled by using an 
IsExpression to test whether a type supports such an operation?

Stewart.