[Dlang-study] [lifetime] On Existing Owning Types - A useful stopgap?

[Matt Kline]

While this research group's initial and foremost focus is on the 
future of lifetimes and reference counting in D, the existing 
owning types still need improvement. Though not safe from escapes 
(as Andrei has demonstrated) they, at the very least, prove to be 
a useful stopgap while new language work is done.

Unique and RefCounted have suffered from bit rot and should be 
revamped to remove some of their warts and historical 
restrictions. A few months back, I worked successfully with 
Martin Nowak, Dicebot, and Jakob Ovrum to fix up Unique 
(https://github.com/D-Programming-Language/phobos/pull/3139). 
Unfortunately it was backed out right before 2.068 due to a few 
lingering issues surrounding destruction of objects referenced 
via their interfaces. As far as I know, Martin did some later 
work at https://github.com/MartinNowak/phobos/tree/smartRefs 
before being drawn away by other concerns, and I disappeared due 
to some events in my personal life. Hopefully Martin sees this, 
as I'd love to coordinate and put what finishing touches remain 
to get Unique (hopefully followed by RefCounted) into an improved 
state, but I don't know how to best contact him "out of band".

You can find the dialogue surrounding these changes at the 
previously-linked PR (#3139), and also 
https://github.com/D-Programming-Language/phobos/pull/3225. I'd 
love to get feedback regarding the semantics discussed there.