Imagine swapping your car's entire engine while it's still speeding down the highway, no stopping, no downtime.
That's essentially what the Bun team just pulled off.
Bun is the blazing-fast JavaScript runtime that's been giving Node.js serious competition. Its core was originally written in a language called Zig.
The problem? Zig is fast and powerful, but it leaves plenty of room for memory management mistakes, the kind that cause memory leaks, where your app quietly eats up more and more RAM without letting go.
The fix? Rewrite all 535,000 lines of code in Rust, a language with a built-in safety net called the borrow checker that catches these memory errors before they ever happen.
This kind of rewrite was originally estimated to take a full year of dedicated engineering work.
With AI assistance, the team finished it in just four months, eliminating a huge number of memory-related bugs along the way.
This isn't just a technical milestone, it's proof that AI has moved beyond writing simple snippets into becoming a genuine partner in massive infrastructure rewrites.
The future isn't about replacing engineers, it's about engineers who use AI well suddenly doing in months what used to take years.
🔗 Original Source & Reference: https://www.infoq.com/news/2026/09/bun-AI-rewrite-zig-rust-4-months/?utm_campaign=infoq_content&utm_source=infoq&utm_medium=feed&utm_term=global
Published automatically via FeedMind AI Content Pipeline.
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