Intersections and Unions in Practice; Failure of Type Preservation with Unions
I discuss the perhaps surprising fact that union and intersection types are quite actively used and promoted for languages like TypeScript, also OO languages like Scala. I also try to explain briefly a counterexample to type preservation with union types, which you can find at the start of Section 2 of Barbanera and Dezani-Ciancaglini's paper "Intersection and Union Types: Syntax and Semantics", where it is attributed to Benjamin Pierce.
Iowa Type Theory Commute
en-usMarch 22, 2021