Author here. The first draft of this post spent a lot more time talking about Move. But I think the real question is: What syntax would let us author self-refer

Author here. The first draft of this post spent a lot more time talking about Move. But I think the real question is: What syntax would let us author self-referential types. And, in a way that doesn't require Box-ing everything. (Rust's mantra is abstraction without overhead.) But then I thought about it more. Whatever you call it - Pin or Move - the point is to say "this struct contains a borrowed field". But we never needed Pin for local variables in functions - even when they're borrowed - because the borrow checker understands whats going on. The "Pin" is implicit. Pin also doesn't describe all the other semantics of a borrowed value correctly - like how borrowed values are immutable. I suspect if the borrow checker understood the semantics of borrowed struct fields (just like it does with local variables), then we might not need Pin or Move at all.