Typing Non-uniform Concurrent Objects

Concurrent objects may o#er services non-uniformly, constraining the acceptance of messages on the states of objects. We advocate a looser view of communication errors. Safe programmes must guarantee that every message has a chance of being received if it requests a method that may become enabled at some point in the future. We formalise non-uniform concurrent objects in T yCO, a name-passing object calculus, and ensure program safety via a type system. Types are terms of a process algebra that describes dynamic aspects of the behaviour of objects