Try `rustup target add aarch64-apple-ios` and see how far you get. It's a tier 2 platform so it usually has builds available. But the iOS targets are some of th

Try `rustup target add aarch64-apple-ios` and see how far you get. It's a tier 2 platform so it usually has builds available. But the iOS targets are some of the least tested for Rust. I have no idea if they work! The process for adding tier 2 platforms isn't well defined but is closely related to ease of automation. If it can be done in a Docker container then it is simple to build std and ship it. Right now we're enthusiastic about this level of support - we can provide builds of std for lots of things. As long as somebody cares just enough to keep std building, which is pretty easy to do. Whether those builds work at all is a different matter! We don't run tests on most tier 2 platforms. It's a big commitment to do so, even more to keep the tree green. Personally, I really want to say that in time Rust will have perfect test and build automation on all platforms that matter even a little bit. All platforms are on a slow treadmill to perfection. They all come with maintenance burden, but the more successful the project is the more maintenance (and perfection) we can afford. Hm, I hope that's how it works...