We present improvements we made to our tool coq-of-solidity to formally verify Solidity smart contracts for any advanced properties, relying on the proof assistant 🐓 Coq. The idea is to be able to prove the full absence of bugs ✨ in very complex contracts, like L1 verifiers for zero-knowledge L2s 🕵️, or contracts with very large amounts of money 💰 (in the billions).
In this blog post, we present how we developed an effect inference mechanism to translate optimized Yul code combining variable mutations and control flow with loops and nested premature returns (break, continue, and leave) to a clean 🧼 purely functional representation in the proof system Coq.