In a sense, kinda? The function colour problem is that you can't call an async API from a non-async caller without modifying the entire call chain (or blocking

In a sense, kinda? The function colour problem is that you can't call an async API from a non-async caller without modifying the entire call chain (or blocking the full thread). In async/await languages the conflict comes from changing the return types; the syntax is orthogonal. Maybe in practice some properties of code are better off being whole-program than represented as types, even if they're less modular or harder to check. Also thanks for the reference, I haven't touched Haskell in ages; I'm more of an F# and OCaml guy.