Worked on enhancing macro systems in both rust-lang/rust and rust-lang/rust-analyzer, focusing on expanding macro capabilities and improving developer experience. Introduced support for lifetime repeats in macros, enabling more flexible macro definitions and updating parsing logic to handle lifetime separators. Refactored macro expansion pretty printing to better distinguish identifier types, which improved test output correctness and readability. Addressed formatting inconsistencies in macro expansion tests, particularly around lifetime identifiers, to ensure reliable test results. Leveraged expertise in Rust, macro development, and code refactoring to deliver four features and one bug fix, demonstrating depth in Rust compiler internals and metaprogramming techniques.