> On the other hand, this doesn't sound to me like an upside. Of course it's fine and well if it's easy to do this. But hopefully you'd prefer not to have to... ?

Why wouldn't you? You can often make your code simpler and more performant by using certain allocation strategy rather than relying on global allocator. Malloc/Free style strategy is also very error prone with complex hierarchical data structures where for example arena allocation can tie the whole lifetime to a single deallocation.

> Would appreciate some explanation of the theory here. Though it does occur to me that the languages I can easily think of with "coloured" async also don't exactly statically link everything all the ti

Async is moot point, it does not exist in zig right now, it used to but it was removed. There are plans to reintroduce it back, but using async as any sort of benefit for zig is not being honest.

Regarding async I kind of agree with you right now, but the new design is there and currently getting implemented. If you don’t believe it will work out or need to use async right now sure, use something else. It is not a stable language yet and very much WIP. I don’t think it’s dishonest to write about something that has a design and is worked on right now with a realistic chance of working out.

Sure and I'm excited for it (especially stackless), but I'd be wary of marketing something that doesn't actually exist yet.