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How to speed up the Rust compiler in September 2026

279 points · 171 comments · trickypr

  1. slowin · · focus · HN ↗
    I've moved from Rust to Go for most things because in the era of agents, being able to iterate quickly on a project is a huge advantage and Rust is way, way slower than Go for compilation. There are times when Rust is more appropriate, but for the vast majority of things Go is perfectly fine.
    1. Bolwin · · focus · HN ↗
      I don't really understand why Rust seems to be the go-to language for llms. Yes sure it has a good type system, but in practice llms seem to trip over it as much as I do, and given how fast llms are at writing code, that just makes compile times a much larger bottleneck.
      1. GuB-42 · · focus · HN ↗
        Rust and LLMs are a good match.

        Rust is built on the idea that code that compile must be correct, to the best of its abilities. LLMs are fast and sloppy, Rust keeps them in check by not letting them get away with preventable bugs.

        Of course, Rust can't do anything for spec bugs, like making the stop light green when it should be red, but it can help with crashes and vulnerabilities.

        1. GuB-42 · · focus · HN ↗
          Another thing I might add is that Rust is a relatively popular language, with a culture of writing high quality code. Many people, starting by those of Mozilla chose Rust to write security-critical, efficient software. They wouldn't chose it for throwaway, low skill, non-critical code, as there are languages that are more appropriate for this.

          The result is a large amount of high quality code a LLM can train on. Compare to Zig for instance, which is a fine language, but not as popular so lacking in volume for good training. You then can understand why Anthropic ported Bun from Zig to Rust if they intend to vibe code. Languages like PHP, while actually quite decent today, have a long history of terrible code, so not great for a LLM as most of its training dataset is poisoned.

          The unfortunate part is that it may not last. If Rust becomes the de-facto language for LLM production, overall quality may decrease. It is a common problem with many machine learning techniques including LLMs: feeding them their own output tend to decrease quality.

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