Increasing the Expressiveness of a Gradual Verifier

Abstract: Static verification provides strong correctness guarantees for code; however, fully specifying programs for static verification is a complex, burdensome process for users. Gradual verification was introduced to make this process easier by supporting the verification of partially specified programs. The only currently working gradual verifier, Gradual C0, successfully verifies heap manipulating programs, but lacks expressiveness in its specification language. This paper describes the design and implementation of an extension to Gradual C0 that supports unfolding expressions, which allow more intuitive specifications of recursive heap data structures.