Worked on the ocaml/ocaml repository to enhance error reporting for recursive modules by introducing an abstract typing environment that safely prints type cycles and clarifies error messages. Leveraged OCaml and expertise in type system design, error handling, and module systems to address issues where recursive module signatures could previously cause infinite loops or obscure errors. Developed explicit error messages that detail the origin of abstract types within recursive module signatures, improving clarity for developers. Added comprehensive tests to ensure correctness and termination of the new error reporting approach, resulting in faster debugging and more reliable type-checking for complex module structures.