Tom Schrijvers, Simon Peyton Jones, Martin Sulzmann, and Dimitrios Vytiniotis
GADTs have proven to be an invaluable language extension, a.o. for ensuring data invariants and program correctness. Unfortunately, they pose a tough problem for type inference: we lose the principal-type property, which is necessary for modular type inference.
We present a novel and simplified type inference approach for local type assumptions from GADT pattern matches. Our approach is complete and decidable, while more liberal than previous such approaches.
In Proceedings of the 14th ACM SIGPLAN International Conference on Functional Programming
Publisher Association for Computing Machinery, Inc.
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