RACE: Semantic-linker approach to stable cross-crate ABI without runtime overhead

You're right that this is high-level. The post was intentionally framed as a concept exploration rather than an implementation proposal - the goal was to get exactly this kind of feedback on where the hard parts actually are. The linker question and the polymorphisation history are gaps I wasn't aware of. Would you say the BTF/CO-RE direction is more tractable than the Swift Witness Tables approach for Rust's use cases?