Bun Has Been Converted to Rust. Now What?

Anthropic's AI agents converted Bun's JavaScript runtime from Zig to Rust in nine days, achieving a 99.8% test pass rate and a smaller binary with neutral-to-faster performance. However, the rewrite contains over 10,000 unsafe blocks across 700+ files—two orders of magnitude more than comparable Rust projects—because the translation faithfully ported Zig's manual memory management rather than embracing Rust's idiomatic safety features, meaning the stated goal of compiler-assisted memory safety was not actually achieved.