TypeDis: A Type System for Disentanglement
Year: 2026
Type: article
Abstract: Disentanglement is a runtime property of parallel programs guaranteeing that parallel tasks remain oblivious to each other’s allocations. As demonstrated in the MaPLe compiler and run-time system, disentanglement can be exploited for fast automatic memory management, especially task-local garbage collection with no synchronization between parallel tasks. However, as a low-level property, disentanglement can be difficult to reason about for programmers. The only means of statically verifying disentanglement so far has been DisLog, an Iris-fueled variant of separation logic, mechanized in the Rocq proof assistant. DisLog is a fully-featured program logic, allowing for proof of functional correctness as well as verification of disentanglement. Yet its employment requires significant expertise and per-program proof effort. This paper explores the route of automatic verification via a type system, ensuring that any well-typed program is disentangled and lifting the burden of carrying out manual proofs from the programmer. It contributes TypeDis, a type system inspired by region types, where each type is annotated with a timestamp, identifying the task that allocated it. TypeDis supports iso-recursive types as well as polymorphism over both types and timestamps. Crucially, timestamps are allowed to change during type-checking, at join points as well as via a form of subtyping, dubbed subtiming . The paper illustrates TypeDis and its features on a range of examples. The soundness of TypeDis and the examples are mechanized in the Rocq proof assistant, using an improved version of DisLog, dubbed DisLog2.
DOI: 10.1145/3776655
Authors: Alexandre Moine, Stephanie Balzer, Alex Xu, Sam Westrick
Institutions: New York University, Carnegie Mellon University
Language: English
Subfield: Artificial Intelligence
Field: Computer Science
Domain: Physical Sciences
Open Access status: diamond
OpenAlex ID: W4416931768