I'm not sure I quite see the analogy to COMEFROM. The "problem" with COMEFROM is that at the "target" location (the one control comes from) there is no in-sour

I'm not sure I quite see the analogy to COMEFROM. The "problem" with COMEFROM is that at the "target" location (the one control comes from) there is no in-source indication of the control flow transfer. So what looks like linear code turns out to have this unexpected detour to the location of the COMEFROM instruction. This hinders understandability of the code. "await" in JS doesn't have that problem: there is an explicit control flow operation, in the form of resolving a promise, that eventually transfers control to the location of the "await" call. And even then, it's async from a run-to-completion perspective, so doesn't affect linear code, modulo other await calls. I guess the concern is that you could have linear code that calls a function, which does an "await" and you would effectively have a control flow detour that's hidden from view? In that sense, I guess this is sort of like COMEFROM... At least you have to explicitly opt in (via "async function", or async module) for it to be a problem. Anyway, a better analogy from my point of view is that async/await is a very limited form of call-with-current-continuation or so. And with generator functions, JS already had that sort of, but without some of the nice ergonomics.