Worked on enhancing code safety and maintainability in the ruby/ruby and ruby/prism repositories by addressing switch statement fall-through behavior in C code. Introduced the PRISM_FALLTHROUGH macro to explicitly mark intentional fall-through cases, enabling compiler warnings for unintended behavior and reducing the risk of silent bugs. Leveraged C programming, Makefile build systems, and compiler flags to align code analysis practices across both repositories. The approach improved code clarity and traceability by unifying fall-through handling, supporting static analysis integration, and ensuring consistent safety standards. These changes contributed to more robust and maintainable codebases without introducing new bugs during the development period.