I've skimmed through the "mutable value semantics" paper: do I understand correctly that authors suggest replacing references and pointers with either: a) nested structs (with some indirection via `Any` with runtime-checks); b) array indices?

The following phrases got my eye: "It is reasonable to ask, then, how we can use mutable value types to represent self-referential data structures, such as doubly linked lists and directed graphs. In fact, any arbitrary graph can be represented as an adjacency list. For example, a vertex set might be represented as an array, each element of which contains an array of outgoing edge destination indices.". I don't see how one can reasonably implement doubly-linked list without re-inventing memory heap and some kind of garbage collection in the implementation.

UPD: found some discussion at https://github.com/orgs/val-lang/discussions/736 , seems that there will be some escape hatches akin to Rust's `unsafe`. That resolves all issues, and "whether the safe subset of Val is enough for reasonable application" question is open to long years of debate.