Worked on the zed-industries/zed repository to address a critical macOS font fallback issue, focusing on stability and platform-specific reliability. Using Rust and CoreFoundation, refactored the font descriptor handling logic by replacing a lazy iterator map with a for loop, ensuring that side effects required by CFArrayAppendValue were properly executed. This change resolved missing font descriptors in the fallback path, leading to more consistent font rendering on macOS and reducing user-facing font issues. The work emphasized disciplined code refactoring and maintainability, aligning the implementation with expected system behavior while prioritizing correctness and robustness over new feature development.