Worked on stabilizing AddressSanitizer (ASAN) detection in the facebook/folly repository to address test flakiness on iOS builds with the new Xcode toolchain. Focused on C++ development and compiler feature detection, the solution replaced reliance on deprecated ASAN macros by implementing a clang-based fallback using __has_feature(address_sanitizer). This approach ensured accurate sanitizer detection across toolchains, reducing false positives and improving continuous integration reliability. The patch enhanced memory management diagnostics and streamlined debugging by aligning ASAN checks with updated toolchain behavior. All changes were reviewed and merged through a dedicated differential revision, reflecting careful attention to cross-platform compatibility and build stability.