With the possible exception of tail calls (which would require a bit of work), I don't see how any of those issues won't be better served by JS than by WASM, ev

With the possible exception of tail calls (which would require a bit of work), I don't see how any of those issues won't be better served by JS than by WASM, even if you did work against the JIT, and for less effort and with more features. It's just really hard to beat decent JITs with AOT compilation for an untyped language -- and V8's JIT is more than just decent -- even when the JIT is having a bad day, not without some very powerful whole-program analysis, and that costs a lot of time and money. But V8 is especially well optimized for a "broken", or "preempted" control flow, as that's just how JS is written, with or without async/await. Native targets are another matter, of course. Anyway, it would be interesting to see results. Beating BEAM's performance is not hard. Thank you for your answer.