Variant Region Types

Region-based memory management has been shown to be an effective alternative that can co-exist with garbage collectors in memory managed languages especially for Real-Time and Big Data applications. In this paper we propose a novel variant region type system that extends our previous Java region types to Generic Java. The main difficulties are given by the type variables used by Generic Java. Our proposal is based on a modular flow analysis that captures regions lifetime relations via subtyping constraints at the method boundary. Our variant region type system guarantees that well-typed Generic Java programs use lexically-scoped regions and never create dangling references in the store and on the program stack.