Worked on the facebook/react repository to enhance the React compiler’s validation logic for useEffect hooks involving namespace imports. Addressed a subtle bug where setState calls inside useEffect were not correctly recognized when accessed via namespace imports, leading to false negatives in static analysis. Implemented a targeted fix in TypeScript and JavaScript, refining the compiler’s validation pathways to ensure accurate detection of these patterns. Added a regression test fixture to lock in the correction and prevent future regressions. Focused on compiler development, static analysis, and testing, the work improved long-term code quality and reliability for developers using React with namespace imports.