Explorer Mechanised Verification Patterns for Dafny

In Dafny, the program text is used to both specify and implement programs in the same language [24]. It then uses a fully automated theorem prover to verify that the implementation satisfies the specification. However, the prover often needs further guidance from the user, and another role of the language is to provide such necessary hints and guidance. In this paper, we present a set of verification patterns to support this process. In previous work, we have developed a tactic language for Dafny, where users can encode their verification patterns and re-apply them for several proof tasks [16]. We extend this language with new features, implement our patterns in this tactic language and show, through experiments, generality of the patterns, and applicability of the tactic language.