Worked on the rust-lang/gcc repository to enhance type safety and maintainability within the GCC codebase. Focused on compiler development using C++ and deep knowledge of type systems, the work involved fixing a bug by enforcing that CONJ_EXPR is used exclusively with COMPLEX_TYPE in tree-cfg.cc, thereby tightening type verification and reducing the risk of incorrect abstract syntax tree construction. Additionally, the error handling logic was refactored to improve code readability and facilitate future maintenance. These changes increased the reliability of CONJ_EXPR handling and laid a stronger foundation for ongoing improvements in type checking and compiler robustness.