Rust is popular because it helps developers write fast, safe, and reliable software. But one common frustration is slow compile times, especially as projects grow larger and dependencies pile up. This can turn what should be quick builds into lengthy waits, slowing down your workflow. Luckily, there are several practical ways to make Rust compile faster without major changes to your habits.

Keep Your Toolchain Updated and Consistent

The simplest step is to ensure your Rust toolchain is always up to date. Running rustup update regularly brings in the latest compiler improvements and optimizations. These updates often include tweaks to rustc and LLVM, which can significantly reduce compile times over time. If you’re working on a team or want consistency across projects, you can pin your project’s Rust version to a specific release. This helps avoid unexpected slowdowns caused by incompatible updates, while still benefiting from targeted improvements.

Using a fixed version can be done by adding a configuration file that specifies the desired Rust channel, such as “1.85”. Keeping your toolchain current ensures you’re taking advantage of ongoing efforts to make compilation faster and more efficient.

Minimize Work During Development with Checks and Caching

One of the best ways to speed up development is to avoid unnecessary full compilations. Instead of building everything from scratch every time, developers can run cargo check. This command quickly verifies if the code would compile without actually producing compiled binaries. Since it skips the heavy parts of compilation, it’s much faster and is great for routine syntax and type checks.

Keep in mind that cargo check still needs to compile dependencies if they haven’t been built before. Once dependencies are built, subsequent checks run much faster. To further improve build times, tools like sccache can cache compiler artifacts. This is especially useful in team environments where multiple developers share build artifacts. Using a shared cache reduces redundant work and speeds up rebuilds across multiple projects or team members.

Another trick is to modularize your code by turning some dependencies into dynamically linked libraries. While not native to Rust, this approach allows parts of your code to be compiled separately and linked at runtime, cutting down on compilation time for changes in other parts of your project.

Optimize Your Build Process and Dependencies

Reducing the number of dependencies and simplifying build scripts can also help. Large dependency trees mean more code to compile, which adds to build times. Regularly reviewing and trimming unnecessary dependencies can make a noticeable difference. Additionally, enabling incremental compilation allows rustc to reuse parts of previous builds, making subsequent compilations faster.

Using features like cargo’s incremental mode or compiler flags to limit re-compilation scope can further speed things up. Also, consider splitting large projects into smaller crates or modules. This way, changes in one part don’t require rebuilding the entire project, saving you time and frustration.

In sum, while Rust’s compile times can sometimes be frustrating, there are many strategies to improve speed. Keeping your tools updated, avoiding unnecessary full builds, caching, and optimizing dependencies are all effective steps. With these in place, developers can enjoy the benefits of Rust without the long waits, making development smoother and more productive.

Inspired by

• https://www.infoworld.com/article/4115425/rust-slow-to-compile-heres-how-to-speed-it-up.html

Sources

• github.com
• github.com
• kra.hn
• feldera.com
• rust-lang.org