Good tools can bring mechanical verification to programs written in mainstream functional languages. We use <pre>hs-to-coq</pre> to translate significant portions of Haskell’s <pre>containers</pre> library into Coq, and verify it against specifications that we derive from a variety of sources including type class laws, the library’s test suite, and interfaces from Coq’s standard library. Our work shows that it is feasible to verify mature, widely-used, highly optimized, and unmodified Haskell code. We also learn more about the theory of weight-balanced trees, extend <pre>hs-to-coq</pre> to handle partiality, and – since we found no bugs – attest to the superb quality of well-tested functional code.

@article{paperbot294,
  title = {Ready, set, verify! applying hs-to-coq to real-world Haskell code (experience report)},
  author = {Joachim Breitner and Antal Spector-Zabusky and Yao Li and Christine Rizkallah and John Wiegley and Stephanie Weirich},
  journal = {Proceedings of the ACM on Programming Languages},
  volume = {2},
  number = {ICFP},
  year = {2018},
  doi = {10.1145/3236784}
}