Worked on the rust-lang/rust repository to improve build reliability by addressing a macro used for LLVM version checks. Focused on compiler design and C++ development, the work involved correcting a conditional macro from LLVM_VERSION_LE to LLVM_VERSION_LT, ensuring accurate version gating for LLVM dependencies. This change enhanced the stability and maintainability of the build process, reducing the risk of misbehavior in continuous integration and downstream tooling. The approach prioritized correctness and clarity in macro usage, supporting future updates to LLVM version requirements. No new features were introduced during this period, with efforts concentrated on bug resolution and codebase maintainability.