Right, but that's what I mean by encoding the assumption of known lifetimes in the language. The design is intended for cases where most lifetimes are known, an

Right, but that's what I mean by encoding the assumption of known lifetimes in the language. The design is intended for cases where most lifetimes are known, and only a few need ref counting, and you can reason about lifetimes and relationships well enough in advance to avoid cycles. At least, that's my understanding (my Rust-fu is shamefully poor).