Kryxen worked on the dart-lang/sdk repository, focusing on enabling dynamic evaluation of FFI usage within expressions. They implemented FFI use-site transformations during expression compilation, allowing APIs such as StructPointer.ref and sizeOf<T>() to be evaluated dynamically. Their approach included adding regression tests to verify both the correctness of these transformations and the robustness of error reporting for unsupported operations. Using Dart and applying principles of compiler design and error handling, Kryxen strengthened the VM expression evaluation path. The work addressed dynamic FFI scenarios, improved test coverage, and enhanced the reliability of expression compilation in the Dart SDK.