Two main papers about this topic AFAIK are: «Counting Immutable Beans» by Sebastian Ullrich and Leonardo de Moura (https://arxiv.org/pdf/1908.05647.pdf) and «Perceus: Garbage Free Reference Counting with Reuse» by Alex Reinking, Ningning Xie,Leonardo de Moura, Daan Leijen (https://dl.acm.org/doi/pdf/10.1145/3453483.3454032).

See also Anton Felix Lorenzen's master thesis: https://antonlorenzen.de/master_thesis_perceus_borrowing.pdf

Mr. Feldman also mentioned some «alias analysis» library «Morphic Solver» from Berkley University, but I cannot find anything about it.

BTW compile time reference counting was already discussed on HN, for example here: https://news.ycombinator.com/item?id=19567666

> Example: A linked list.

IIUC recursive data structures like linked list and trees are not the problem for the static reference counting. Mutation (and, therefore, link cycles) _is_ a problem, but Roc is a clean language with no explicit mutation. =)

> I can see so many basic cases in which it doesn't work

Sometimes runtime reference counting is still used. But, of course, in way more complex situations than just processing a linked list.

> Nitpick: Rc and Arc are not traits.

Of course, my fault. I haven't written on Rust for a long time (and never used this language in a serious project).

edit: link added