Scaling Up Delta Debugging of Type Errors

Type error messages of compilers of statically typed functional languages are often inaccurate, making type error debugging hard. Many solutions to the problem have been proposed, but most have been evaluated only with short programs, that is, of fewer than 30 lines. In this paper we note that our own tool for delta debugging type errors scales poorly for large programs. In response we present a new tool that applies a new algorithm for segmenting a large program before the delta debugging algorithm is applied. We propose a framework for quantifying the quality of type error debuggers and apply it to our new tool demonstrating substantial improvement.