Haskell's "mixin modules" AKA backpack are I think the closest thing you're going to get outside of SML (they are a different trade off in the design space, it's not 1-to-1), but they have languished in the broader community due to a couple social factors. They are excellent for many of the same things you use modules for, though, and work just fine in my experience.

On the same note, the lack of some kind of module system along these lines (broadly all defined in terms of "holes" in a compilation unit which are "plugged up" later on at instantiation time), is one of my biggest complaints about Rust. The extensive usage of traits in the broader ecosystem results in this phenomenon (identical to Haskell) where global coherence requires your dependency tree gets tied up in the location of types and their trait impls. In other words, you cannot abstract over your dependencies in a truly modular way.

Global coherence requirements are fine (preferable even!) for many things but if it's the only hammer you have, well, you know the rest of the metaphor.

> Anyway I think there is a proposal for it so it'll probably work its way in eventually.

Modular implicits have been shelved indefinitely from what I understand, if that's what you're referring to.