[sweetsocks21]

OCaml has full multicore support with algebraic effects now. The effect system makes things like async very nice as there's no function "coloring" problem: https://discuss.ocaml.org/t/ocaml-5-0-0-is-out/10974

But I don't believe the effects are tracked in the type system yet, but that's on it way.

[lambda_foo]

The type system for effects is an ongoing research effort. For now you get unhandled effect exceptions at runtime.

With Multicore OCaml we gained thread sanitizer support and a reasonable memory model. Combined they give you tools for reasoning about data races and finding them. https://ocaml.org/manual/5.3/tsan.html