Happy new week Rustaceans!
In this issue, we cover Rust’s LLM policy, spotlight a project, and highlight 10 awesome links of the week.
Here’s issue 131.
Five teams inside the Rust project has adopted a formal LLM policy for the rust-lang/rust monorepo, and it’s a pretty smart middle finger to the current chaos. Authored by Jynn Nelson, the rules don’t ban AI outright.
Instead they draw a clear line, LLMs are fine for asking questions, analyzing, distilling, suggesting, or reviewing. They’re heavily restricted when it comes to creating. If your code, issue report, or GitHub comment was cooked up by a model, you have to say so. No more stealthing polished patches that look human but smell like autocomplete on steroids.
The motivation is painfully familiar to anyone who’s spent time in a high-volume repo. Polished PRs used to signal that someone actually understood the change and might stick around. Now they just signal that someone typed a good prompt. Review bandwidth gets hammered by shotgun submissions. And the classic copy-paste loop is pure time theft. Reviewers aren’t here to debate with a chatbot. They want your brain, not the model’s temperature setting.
What’s cool is how pragmatic the rules feel. LLM-generated code has to clear a higher bar than human work: tests are mandatory, soundness-critical changes are basically off-limits unless you’re already a domain expert, and disclosure is non-negotiable.
Reviewers can close non-compliant PRs without guilt and point people to a mentoring channel. No one’s forced to review AI output if they don’t want to. Personally, I like the honesty of it.
A lot of projects are still pretending the AI flood isn’t happening or swinging between total bans and free-for-alls. Rust is treating it like any other contribution risk: make the expectations public so new people don’t get blindsided and existing maintainers don’t burn out.
It’s not perfect, and the author admits as much, but writing the rules down beats the previous wild west with occasional moderation notes approach. At least now everyone knows the game.
Just remember, if your PR looks too good to be true, someone’s going to ask whether you or Claude wrote it. Better have an answer ready.
libc provides all of the definitions necessary to easily interoperate with C code (or C-like code) on each of the platforms that Rust supports.
Libc exists because interoperating with C (and C-like) system libraries is messy, platform-specific, and easy to get wrong.
Here’s why it’s still the default choice years later:
Everything lives at the crate root. No hunting through modules, just libc::c_int, libc::EINVAL, libc::malloc.
The definitions are platform-accurate by construction. What you see is what the OS actually provides.
It’s the shared foundation for a huge chunk of the ecosystem. When something low-level needs to work everywhere, this is usually how it starts.
Libc is open-source at https://github.com/rust-lang/libc.
Polonius Alpha borrow checker got enabled on nightly with flow-sensitive lifetime analysis aiming for stabilization later this year after testing. Rust Funding Team raises $350K for Maintainer-in-Residence program, with year-long flat-rate contracts prioritizing key teams, and first announcements due end of August.
David Tolnay open-sourced chapter-tgz, a crate for creating .tar.gz files with embedded chapter markers that enable O(1) skipping of entry groups and true parallel decompression.
Last week marked 10 years since Tokio was announced. A decade later, it's still the async runtime everyone ends up using. Not bad for a ‘temporary’ dependency.
Cargo-fixit is a prototype drop-in replacement for cargo fix that is significantly faster.
Serhii’s Branchless Rust shows how a filter avoids unpredictable ifs via always-write + conditional index advance, making the 50% worst case ~4× faster on shuffled data.
The Rustaceans at Deno open-sourced celld, a daemon that runs Cloudflare Workers and Durable Objects on your own machines.
Nia Deckers (RustNL-sponsored compiler engineer) discusses her Rust journey, the Move trait, effect systems, Miri FFI segfault handling, and contributing to the project. [video]
Ed Page’s vision for Cargo outlines improved dependency discovery and auditing, faster builds, greater adaptability via plumbing commands, and stronger maintenance elevating Rust’s workflow.
Eshed Schacham wrote Downcasting Arcs in Rust to concrete types with raw pointers, using assert_unchecked to guarantee alignment and optimize assembly.
ImplRust published a tutorial showing how to blink the STM32 Blue Pill’s onboard LED (PC13) with Embedded Rust using stm32f1xx-hal, ST-LINK, and a simple delay loop.
CodeCrafters created amazing Rust courses that push your skills beyond the basics.
You’ll have fun building real-world projects from scratch, including Git, Docker, Redis, Kafka, SQLite, Grep, BitTorrent, HTTP Server, an Interpreter, and DNS.
The courses are self-paced, so you can learn at your own speed.
Join for free and get 40% off when you upgrade. [affiliate]
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Started playing Among Us and I am really enjoying the game.
See you next week!
John & Elley.
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