An annotation system for specifying aliasing invariants on object fields

Aliasing is an essential concept in programming languages, used to represent self-referential structures and share data between components. Unfortunately, it is also a common source of software bugs that are often hard to find and fix. In response, a plethora of methods have been proposed to tame aliasing. They usually rely on uniqueness and/or immutability to establish strong safety guarantees, but are often too restrictive to write common idioms, as they generally enforce a single-writer policy. This paper suggests to relax this constraint by focusing on the specific parts of an object representation for which aliasing should be controlled, otherwise allowing unrestricted mutations of its fields.