A versatile constraint-based type inference system
François Pottier · Nordic journal of computing · 2000
The combination of subtyping, conditional constraints and rows yields a powerful constraint-based type inference system. We illustrate this claim by proposing solutions to three delicate type inference problems: accurate pattern matchings, record concatenation, and first-class messages. Previously known solutions involved a different technique in each case: our theoretical contribution is in using only a single set of tools. On the practical side, this allows all three problems to benefit from a common set of constraint simplification techniques, a formal description of which is given in an appendix.