CRUST-Bench: A Comprehensive Benchmark for C-to-safe-Rust Transpilation
Authors: name: Anirudh Khatry; name: Robert Zhang; name: Jia Pan; name: Ziteng Wang; name: Qiaochu Chen; name: Greg Durrett; name: Isil Dillig
Published: 2025-04-21 17:33:33

Abstract: C-to-Rust transpilation is essential for modernizing legacy C code while
enhancing safety and interoperability with modern Rust ecosystems. However, no
dataset currently exists for evaluating whether a system can transpile C into
safe Rust that passes a set of test cases. We introduce CRUST-Bench, a dataset
of 100 C repositories, each paired with manually-written interfaces in safe
Rust as well as test cases that can be used to validate correctness of the
transpilation. By considering entire repositories rather than isolated
functions, CRUST-Bench captures the challenges of translating complex projects
with dependencies across multiple files. The provided Rust interfaces provide
explicit specifications that ensure adherence to idiomatic, memory-safe Rust
patterns, while the accompanying test cases enforce functional correctness. We
evaluate state-of-the-art large language models (LLMs) on this task and find
that safe and idiomatic Rust generation is still a challenging problem for
various state-of-the-art methods and techniques. We also provide insights into
the errors LLMs usually make in transpiling code from C to safe Rust. The best
performing model, OpenAI o1, is able to solve only 15 tasks in a single-shot
setting. Improvements on CRUST-Bench would lead to improved transpilation
systems that can reason about complex scenarios and help in migrating legacy
codebases from C into languages like Rust that ensure memory safety. You can
find the dataset and code at https://github.com/anirudhkhatry/CRUST-bench.