re: Issue: REST-LIST-ALLOCATION (Version 3)

[Kim A. Barrett <IIM@ECLA.USC.EDU>]

NEWLY-ALLOCATED: NO
MUST-SHARE: NO

I feel that both of these take away too much implementation freedom.  Which
leaves us with ...

MAY-SHARE: YES.

But I'd like to see something added that allows the programmer to force copying
when she cares, without requiring an explicit call to COPY-LIST (possibly
featurized).  Note that most cases of COPY-LIST on &REST parameters that I've
seen had nothing to do with the question of whether apply => &rest could share;
they were put in to deal with implementations which always stack-cons &rest
lists.