July 16, 2026
Rewrite Club: speed dates safety
How Our Rust-to-Zig Rewrite Is Going
Roc’s giant code makeover is real, and the comments are already fighting about speed vs safety
TLDR: Roc’s team says its long rewrite is finally caught up with the old version, a big step toward a public release. Commenters immediately turned that win into a messy debate over whether faster coding tools are worth giving up some of Rust’s reputation for protection against nasty mistakes.
A small programming language project called Roc just hit a huge milestone: after 487 days of rewriting its compiler from Rust into Zig, the new version can finally do everything the old one could. The team is celebrating with a cute little game, Rocci Bird, now running on the new setup with a much smaller file size. Very wholesome, very nerd victory lap. But in the comments? Instant chaos.
The loudest reaction was pure surprise. One person basically blurted out, wait, Roc is still alive? That set the tone: half the crowd was impressed this ambitious project is still charging ahead, while the other half treated the rewrite like the opening bell for yet another speed versus safety cage match. Zig fans were drooling over ultra-fast rebuild times, with one commenter saying 35 milliseconds was the detail that “sold” them. That’s computer-nerd catnip: less waiting, more doing.
But the skeptics came armed. One summed up the mood perfectly: they want to go fast, “but not… just to shoot my foot off.” Ouch. Another pushed back on the post’s framing around unsafe memory tricks, basically saying, hold on, that’s being overstated. And then came the classic comments-section energy: someone went full receipt mode, questioning whether Zig’s safety claims around nasty memory bugs really hold up. So yes, Roc got its big win — but the real spectacle was the crowd turning it into a dramatic referendum on whether faster tools are worth feeling a little more exposed.
Key Points
- •Roc’s compiler rewrite from roughly 300,000 lines of Rust to Zig has reached feature parity with the original compiler after 487 days.
- •The milestone enabled the WASM-4 game Rocci Bird to run on the new compiler, with a reported 31KB WebAssembly output using `roc build --opt=size`.
- •The article states this is not a formal release, and the team is targeting Roc version 0.1.0 later this year.
- •The post credits numerous contributors for work on the parser, type-checker, lambda set resolution, browser support, package APIs, bug investigation, and educational materials.
- •The article compares Roc’s rewrite duration with Bun’s 11-day Zig-to-Rust rewrite and says the difference reflects different goals, especially that Roc’s rewrite involved major changes rather than a direct port.