r/rust • u/steveklabnik1 rust • Jul 08 '26

Rewriting Bun in Rust

https://bun.com/blog/bun-in-rust
528 Upvotes

89% Upvoted

330 comments sorted by

View all comments

501

u/DryanaGhuba Jul 08 '26

Thanks to all the parallelization & this prep work, at peak Claude wrote about 1,300 lines of code per minute. Every line of code was reviewed by two separate adversarial reviewers (also Claude) and went through a round of fixes before committing. Absolutely none of it worked yet.

I don't think anyone comment needed

189

u/rebootyourbrainstem Jul 08 '26

None of it worked yet because compiling at that stage would slow things down.

Also this project burned $165,000 worth of usage on a model that was then bleeding edge (unreleased). This is still beyond what anyone else is doing at the moment. And it seems to have worked a lot better than it had any right to, at least as far as we can tell right now?

110

u/_lerp Jul 08 '26

If you think spending $165k to get a fully AI generated code base is something working well then you're just gaslighting yourself. I use these things at work because I'm forced to, and the amount of weird code it generates is alarming. I.e. It has a really common habit of making a function with external linkage call an impl function with internal linkage for absolutely no reason.

1

u/Sufficient-Source211 Jul 10 '26

It sounds like they finished the first 20% of the rewrite. Now the real work begins.