Note Moonbit is a language/platform for industrial usage(not an academic language), I contributed to OCaml so that I am familiar with the good/bad parts of a type system. Its aim is to build fast and run fast, and generate the tiny Wasm output.
Type system is sound, you can take it as Rust(- some features hinder fast compilation) with GC and an emphasis on data oriented programming, so we have ADT, generics, interface and ad-hoc polymorphism. We also plan to make the pattern match more expressive with first class pattern support.
The async story is constrained by the WASM runtime, we will evolve with the Wasm proposal.