C2Rust is a transpiler that converts C99-compliant code to Rust.
The tool addresses the challenge of migrating large C codebases to Rust by automatically translating C code into unsafe Rust that preserves the original functionality. The transpiler produces output that closely mirrors the input C code, ensuring that existing test suites continue to pass after translation. This approach prioritizes correctness and compatibility over idiomatic Rust, treating the transpiled code as a starting point rather than a finished product.
The project is designed for teams managing substantial C codebases who want to gain Rust's memory safety guarantees without rewriting from scratch. It suits projects where preserving exact behavior during migration is critical. The tool acknowledges that its output is unsafe and unidiomatic, requiring additional refinement work. To support this refinement, C2Rust provides a deterministic refactoring tool for automated cleanup and an LLM-powered postprocessor for more complex transformations, though the latter can introduce errors and should be paired with robust testing. The transpiler can be tested interactively through Compiler Explorer without installation.
Development activity shows consistent engagement with the codebase through regular commits addressing both new features and bug fixes. The project maintains active documentation efforts, including an in-tree manual that receives updates, though some older online documentation has not been synchronized. The build system demonstrates careful attention to platform compatibility, with explicit support for multiple LLVM versions and detailed installation instructions across Ubuntu, Debian, Arch Linux, NixOS, and macOS. The master branch is noted as under constant development with potential for instability, indicating active experimentation alongside the stable release channel available through standard package managers.
