In November 2025, Matt Leppanen enhanced linting accuracy in the astral-sh/ruff repository by extending the used-dummy-variable rule to detect dummy variables within comprehensions, including list, dict, set, and generator expressions. He refined the static analysis scope and binding model in Rust, introducing support for generator scopes and loop variable bindings to close gaps in dummy variable detection. The work involved a thoughtful refactor of scope validation logic for clarity and maintainability, and was validated with comprehensive test coverage using cargo test. Leveraging both Python and Rust development skills, Matt delivered a targeted, well-tested improvement to static analysis quality.