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refulgentistoday at 2:17 AM2 repliesview on HN

I've seen this sentiment and am a big fan of it, but I was confused by the blog post, and based on your comment you might be able to help: how does Lean help me? FWIW, context is: code Dart/Flutter day to day.

I can think of some strawmen: for example, prove a state machine in Lean, then port the proven version to Dart? But I'm not familiar enough with Lean to know if that's like saying "prove moon made of cheese with JavaScript, then deploy to the US mainframe"


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baqtoday at 10:07 AM

yesterday I had to tell a frontier model to translate my code to tla+ to find a tricky cache invalidation bug which nothing could find - gpt 5.4, gemini 3.1, opus 4.6 all failed. translation took maybe 5 mins, the bug was found in seconds, total time to fix from idea to commit - about 15 mins.

if you can get a model to quickly translate a relevant subset of your code to lean to find tricky bugs and map lean fixes back to your codebase space, you've got yourself a huge unlock. (spoiler alert: you basically can, today)

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Paracompacttoday at 3:01 AM

I don't think he's referring to Lean specifically, but any sort of executable testing methodology. It removes the human in the loop in the confidence assurance story, or at least greatly reduces their labor. You cannot ever get such assurance just by saying, "Well this model seems really smart to me!" At best, you would wind up with AI-Jim.

(One way Lean or Rocq could help you directly, though, would be if you coded your program in it and then compiled it to C via their built-in support for it. Such is very difficult at the moment, however, and in the industry is mostly reserved for low-level, high-consequence systems.)

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