Path dependent types with path-equality

Abstract

While the Scala type system provides expressive features like objects with type members, the lack of equality checking between path-dependent types prohibits some programming idioms. One such an example is abstract domain combinators in implementing static analyzers. In this paper, we propose to extend the Scala type system with path-equality, and formalize it as a DOT variant, π DOT, which supports records with type members and elds. We show that π DOT has the normalization property and prove its type soundness.