As other pointed out, if Arc is not an option, then a well encapsulated raw pointer might just be what's needed. I've implemented several of such data structur

As other pointed out, if Arc is not an option, then a well encapsulated raw pointer might just be what's needed. I've implemented several of such data structures, there is not that many tradeoffs available : safe and easy, or unsafe and fast. The unsafe parts are still much better than raw C. I don't agree that the language and ecosystem is missing a "big piece". Everything is already there.