[PATCH] Have 'this'-returning constructors and destructors to take advantage of the new backend 'returned' attribute

[Stephen Lin]

> Enabling a new and not-necessarily-deeply-tested feature/optimization is
> actually specifically the sort of thing we try *not* to do right before a
> release branch. :)

Oh OK. Well, I just thought it'd be better if the backend and frontend
portions of this went out in the same release. If it's not really
worth it at this point then I'm OK waiting. Let me know.

-Stephen