Richard talks with Predrag Gruevski, author of the cargo-semver-checks tool for detecting accidental semantic versioning mistakes in Rust packages, as well as Trustfall, which is an incredibly flexible query engine. They talk about why semantic versioning is so especially tricky to get right in Rust, tradeoffs in different package managers' approaches to semver in general, and how his work on cargo-semver-checks motivated him to create a tool for querying data in just about any format.