I think Hindley Milner (for decidability) + Linear Types (for resource management) + Refinement Types (for lightly asserting invariants) + Delimited Continuation based Effects (for tracking effectful code) + Unison style Content Addressability (for corralling code changes, documentation, and tests) would make a really nice language for an LLM.

That's in large parts Scala.

It doesn't have Hindley-Milner type inference, but it has very strong type inference.

We will get linearity soon thanks to and as part of the Capybara[1] effort.

Refinement types are already long a reality.

The whole new effect tracking thing is based on delimited continuations.

The Unison style content addressability comes up now and then, maybe it will become a reality at some point. It's though mostly not a language thing but more a build system thing.

Scala is already great for for LLMs also for other reasons:

https://arxiv.org/html/2510.11151v1

[1] https://2025.workshop.scala-lang.org/details/scala-2025/6/Sy...