Worked on the nim-lang/Nim repository to enhance compiler correctness and memory safety, focusing on resolving two critical bugs. Addressed a false-positive use-before-initialization error by refining type evaluation logic, and corrected a use-after-free issue in cursor inference by extending variable liveness during mutation. Both fixes were validated with targeted regression tests and comprehensive compatibility checks across multiple memory management modes, including arc, orc, and refc. Leveraged expertise in Nim, compiler development, and static analysis to ensure reliability and maintain performance neutrality. The work demonstrated careful root-cause analysis and thorough validation, strengthening the compiler’s robustness across diverse code paths.