Worked on the swiftlang/swift-build repository to address CI instability and reduce noise in Xcode builds by implementing a targeted bug fix. The solution involved disabling ASAN container overflow checks specifically for Xcode projects through the introduction of a new libcxx compiler flag, -D_LIBCPP_HAS_ASAN=0. This approach preserved existing build behavior while preventing false positives from the sanitizer, ensuring smoother development workflows. The update included corresponding changes to the test suite to validate the new configuration. The work demonstrated proficiency in C++ and Swift, with a focus on build systems, compiler flags, and testing to maintain compatibility and reliability.