Hi there, I am the Nick whose design we're discussing. You raise some valid points: the blog post enumerates some limitations with Rust's model, but my design (as written) only resolves a subset of those limitations. We probably should have made that a bit clearer.

That said, there is still hope! I have been iterating on the design over the last 9 months and am fairly confident that I can model graphs, as long as a few restrictions are imposed, such as not being able to delete nodes. But I can't prove this will work yet, so we will need to wait and see what the next design iteration looks like. I'm fairly confident that the next iteration will be more powerful than the version presented in OP's blog post.

Good luck! I look forward to seeing the results.