A Kotlin for Rust would be a drop-in replacement where you could have a crate or even just a module written in this hypothetical language and it just works. No bridging or FFI. That’s not Swift.
You all need to stop with the hair-splitting – it's tiresome.
My intention was to offer something that might be of interest to the person I replied to – not to write the official definition of "Kotlin for Rust" which everybody has to agree to. If you think my answer is nonsense, just skip it and read the next one. No need to reply. Nobody profits from this discourse.