an old topic (pun intended)

[Davidson Corry]

I want to point out (quick, before someone else does!) that the 
lowerings I have suggested for old! elsewhere in this thread are naïve. 
In the presence of inheritance, interface contracts, and/or multiple 
subtyping, things can get notably trickier.

That said,
1) I don't think it affects the utility of the old!symbol notation, and
2) old! would be useful even if inherited contracts weren't fully 
handled. (Much more so if they are, of course.)

-- Davidson