Leonard Chan contributed to compiler and systems programming projects, focusing on stability and maintainability. In the llvm/clangir repository, he improved the StackProtector by ensuring that aliased __stack_chk_fail calls in CrossDSOCFI builds are correctly marked as noreturn, preventing runtime crashes and enhancing compiler analysis for non-returning paths. Using C++ and LLVM IR, he addressed low-level crash scenarios in security-critical code. In the rust-lang/rust repository, Leonard streamlined cross-platform support by removing Fuchsia as a sleep target in the Rust standard library’s thread module, reducing maintenance complexity. His work demonstrated depth in Rust, LLVM, and low-level systems programming.