> there's an accepted proposal to bring them back, in which case any function that calls await, or that otherwise has a suspension point, would have to be transformed into a stackless coroutine by the compiler, yes. The plan is for that to happen transparently without requiring an `async` annotation in the function signature, like we already did in the past.

If the compiler will treat functions that call a library function (Future.await) as special and change how the call site is compiled, why not just have an `await` keyword that when present will convert it into a state machine that can be suspended/resumed?

In other words: What is gained by not having a keyword that changes how a function is emitted if the compiler will change it anyway based on detection of a library call?