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deductive-verification-with-dafny-and-why3

Use when an imperative program needs pre-conditions, post-conditions, and loop invariants proved automatically by SMT in Dafny or Why3, short of a tactic prover.

.devin/skills/deductive-verification-with-dafny-and-why3/SKILL.md

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# Deductive verification with Dafny and Why3

## Contract

| Field | Bound contract |
|---|---|
| Trigger | The task is to prove the pre-conditions, post-conditions, and loop invariants of imperative code with an SMT-backed prover: Dafny for annotate-then-verify on executable code, Why3 for multi-prover goals over WhyML. Methodology stays with proof-driven. |
| Authority | Reversible local: writes only Dafny and WhyML source files, prover configuration, and session files under the project; rollback is version control. No remote mutation. |
| Side effect | Local writes to annotated sources, the Why3 user configuration, and `.why3session.xml` proof sessions. No remote mutation. |
| Done | The module verifies with no unproved obligations: `dafny verify` reports zero errors, or every Why3 goal is Valid and `why3 replay` re-confirms the session. |

## Inputs

- Code to verify: Dafny sources (`.dfy`) or WhyML sources (`.mlw`), new or existing.