error: async function is not directly supported yet, but see https://cxx.rs/async.html for a working approach, and https://github.com/pcwalton/cxx-async for some helpers; eventually what you wrote will work but it isn't integrated into the cxx::bridge macro yet --> tests/ui/async_fn.rs:4:9 | 4 | async fn f(); | ^^^^^^^^^^^^^ error: async function is not directly supported yet, but see https://cxx.rs/async.html for a working approach, and https://github.com/pcwalton/cxx-async for some helpers; eventually what you wrote will work but it isn't integrated into the cxx::bridge macro yet --> tests/ui/async_fn.rs:8:9 | 8 | async fn g(); | ^^^^^^^^^^^^^