Comment by zozbot234

You can do it by combining ghostcell/qcell along with some bespoke "static/compile-time reference counting" for the double links part. But ghostcell/qcell is quite difficult to use with Rust's current feature set (it has to use lifetime hacks to place a safe "brand" on type instantiations, a kind of quasi-capability construct), so it hasn't become a part of standard rust so far.