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The Prusti Project: Formal Verification for Rust

Part of the Lecture Notes in Computer Science book series (LNCS,volume 13260)


Rust is a modern systems programming language designed to offer both performance and static safety. A key distinguishing feature is a strong type system, which enforces by default that memory is either shared or mutable, but never both. This guarantee is used to prevent common pitfalls such as memory errors and data races. It can also be used to greatly simplify formal verification, as we demonstrated by developing the Prusti verifier, which can verify rich correctness properties of Rust programs with a very modest annotation overhead. In this paper, we provide an overview of the Prusti project. We outline its main design goals, illustrate examples of its use, and discuss important outcomes from the perspectives of a user, a verification expert, and a tool developer.


  • Rust
  • Deductive verification
  • Separation logic

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  1. 1.

    or its siblings , , , etc.

  2. 2.

    In slight contrast to classical loop invariants, a need only hold for every loop iteration reaching this location inside the loop body.

  3. 3.

    The construct is standard Rust, branching on whether the value can be pattern-matched against (taking the second branch if not, i.e. for ).

  4. 4.

    Values of generic type are compared with the library function from trait , which is specified to satisfy the standard properties of total orders using an external specification; this Prusti feature is explained in Sect. 2.4.

  5. 5.

    External specifications can also be used for functions inside the same crate, allowing developers to apply Prusti without modifying source files, if desired.

  6. 6.

    See for example for an optimisation that used to copy non-duplicable mutable references.


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We warmly thank Nicholas D. Matsakis, Nick Cameron, Derek Dreyer and Ralf Jung for extensive discussions and feedback in the early stages of this project, and are very grateful to Florian Hahn for his work on a precursor to Prusti [20], as well as numerous Master’s and undergraduate students who have since contributed via projects.

This work was partially funded by the Swiss National Science Foundation (SNSF) (Grant No. 200021_169503), the Natural Sciences and Engineering Research Council of Canada (NSERC) (ref. RGPIN-2020-06072), Amazon Research Awards, Meta (then Facebook) Research and the Interchain Foundation.

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Astrauskas, V. et al. (2022). The Prusti Project: Formal Verification for Rust. In: Deshmukh, J.V., Havelund, K., Perez, I. (eds) NASA Formal Methods. NFM 2022. Lecture Notes in Computer Science, vol 13260. Springer, Cham.

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