What we learned with Clippy's feature freeze

Oct. 22, 2025 · blyxyas on behalf of the Clippy team

The feature freeze affecting Clippy has reached its end date. This means that the Clippy project has been accepting pull requests that add new features (and new lints) for a while.

The Clippy team has reviewed the results, and we can say that it's been a success 🎉. It has been so great that we managed to create an all-time peak in the number of pull requests opened in a week.

In this plot we can observe that peak (the red lines mark the start and end of the feature freeze)

Plot of PRs per week, we can see an all-time peak when the feature freeze happens

After some data crunching of those pull requests opened after June 26th, we had 18 pull requests open in that period that added lints. With 326 pull requests open by both new and old contributors, we want to highlight all the new people that started contributing to Clippy, 47 new contributors who opened a total of 195 pull requests.

On a team meeting, we concluded that the results of the feature freeze were positive enough to warrant a future one. The cadence and duration of these is still being decided.

58% of all pull requests by new contributors (114 out of the total 195) were opened by the same person. We held a meeting with her (ada4a on Github) to iron out some of the details of the codebase and our procedures for new contributors. We are currently analyzing that meeting in order to improve the experience for future and current contributors.

We also asked some questions to Ada (ada4a) to include as a mini Q&A, here are some of the answers.

Ada's Q&A

Why do you like contributing to Clippy? What's so fun about it?

I came to enjoy improving the suggestions that Clippy makes: they are fascinating in how they point out the exact part of code that is problematic, and show the (sometimes pretty complex) manipulations required to fix it. Also, It has been empowering to learn the machinery behind the compiler, and use that knowledge to refine these diagnostics even further.

Would you recommend contributing to Clippy? Why or why not?

Yes, for multiple reasons:

  • Rust is (in)famously hard to learn, and to me, Clippy is one of the parts of the toolchain most helpful for beginners, as it teaches idiomatic style and helps discover helpful functions from std -- thus, contributing to it helps reduce the entry barrier of the language.
  • If you, like me, wanted to learn the inner workings of the compiler and contribute to it some day, but were intimidated by the development setup required for that, Clippy could be a nice stepping stone, as hacking on it doesn't require compiling rustc, but it interacts with a lot of compiler's data structures and APIs.