opEquals footprint

[Erik Rasmussen]

I've looked all around in the documentation and forum discussions, and I 
can't find the answer to this simple, but all-important question:

***** What should the type of the parameter to opEquals be??? *****

I can see two possibilities:

A) Object.  This would force you to check the type of the object passed 
in as part of your equivalence check.  Could this perhaps be done at 
compile-time with an is() expression?

B) The same type as the class.  This is fine, but I don't think 
subclasses properly override the superclass's opEquals implementations 
when this is the case.

Can someone settle this?  What is the proper way to implement opEquals??

Thanks,
Erik