> Is the mut marking also for consistency (and/or non-message methods)? Presumably each actor/object would only process one message at a time so could always have full access to all its data.
This is indeed correct: processes have exclusive access to their data and run a single message at a time. Still having to tag methods as mutable is to prevent you from accidentally mutating data, and to keep it consistent with regular methods.
This is all an amazing achievement, congrats on making it so far/long.
I always felt that Rust wasn't a local maxima and there was something that could be added/removed. The only thing I'm not sold on is async (outside of actor use) vs futures where waiting explicitly blocks the waiter, but can be composed without waits. There seems to be some debate around Rust's choice of implementation.
