Worked on the rust-lang/rust repository to reorganize and enhance the Rust test suite for language features, focusing on improving regression testing for macro patterns and borrow-checker scenarios. The approach involved consolidating test files, migrating issues to dedicated directories, and renaming files to clarify test intent and maintain tidy standards. Added detailed descriptions and issue links to test files, which improved documentation and made test coverage more explicit. Leveraged skills in Rust, software testing, and documentation to reduce regression risk and streamline onboarding for contributors, resulting in clearer testing semantics and a more maintainable test infrastructure for future development.