Algebraic Data Types for Language-Integrated Queries

We combine the type error slicing and heuristics based approaches to type error diagnostic improvement within the context of type based security analysis on a let-polymorphic call by value lambda calculus exteded by lists, pairs and the security specific constructs declassify and protect. We define and motivate four classes of heuristics that help diagnose inconsistencies among the constraints, and show their effect on a selection of security incorrect programs.