What "non-OO" methods for representing cyclical data structures are you referring to? The only one I can think of is lots of indirection (e.g. how petgraph does

What "non-OO" methods for representing cyclical data structures are you referring to? The only one I can think of is lots of indirection (e.g. how petgraph does it), which can be too slow (especially for systems programming). As far as I can tell, Rust's model for verified code is pretty hostile to cyclical structures, especially if you want inhomogeneous references (i.e. not everything is an edge on a graph). I don't think you can just sweep this under the rug as "lack of understanding" of Rust's better ways of doing things.