Joanna is a PhD Student at the University of Kent. Their research interests involve improving the experience programmers have when debugging software written in Functional programming languages, particularly issues that arise with type error debugging.
We present a simple method for locating the cause of a type error in a functional program. Understanding the cause of a type error can be hard and for over 30 years researchers have proposed many sophisticated solutions which then hardly made it into practice. We apply Zeller's isolating delta debugging algorithm, using the compiler as a black box. The algorithm uses simple line-based program slicing in the search for a type error location. To improve speed, we incorporate a special handling of parse errors. We implemented the method in a tool and evaluated it for Haskell programs and also some OCaml programs, to demonstrate that it is language agnostic.Slides