> Rust is a complex language prone to refactoring avalanches

This may be so, but LLMs are great at slogging through such tedious repercussions.

I would say if the language prevents sloppy intermediate states, that actually makes it more amenable to AI; if you just half-ass a refactor into a conceptually inconsistent state, it’s possible for bad tests to fail to catch it in Python, say. But if many such incomplete states are just forbidden, then the compiler errors provide a clean objective function that the LLM can keep iterating on.