Professionally, Scala was always my favorite language to work in and I was lucky to get to use it most of my career. It is, however, probably the worst language I’ve experienced using with LLMs. Next worst is any dynamic language: it’s just so hard to not introduce strange bugs after iterating on a large-ish project across multiple agent sessions.

I’ve had good enough experiences with Rust, but actually OCaml has been hands down the language I’ve seen best results with. The quality (and performance) of code is just phenomenal — and the main issue when working as a solo human with the language, namely smaller pool of community libraries, just isn’t an issue any more. Jane Street has really done tremendous work modernizing the language and tooling.