Work

Modeling Reachability Types with Logical Relations: Semantic Type Soundness, Termination, Effect Safety, and Equational Theory

Year: 2025

Type: article

Abstract: Reachability types are a recent proposal to bring Rust-style reasoning about memory properties to higher-level languages, with a focus on higher-order functions, parametric types, and shared mutable state - features that are only partially supported by current techniques as employed in Rust. While prior work has established key type soundness results for reachability types using the usual syntactic techniques of progress and preservation, stronger metatheoretic properties have so far been unexplored. This paper presents an alternative semantic model of reachability types using logical relations, providing a framework in which we study key properties of interest: (1) semantic type soundness, including of not syntactically well-typed code fragments, (2) termination, especially in the presence of higher-order mutable references, (3) effect safety, especially the absence of observable mutation, and, finally, (4) program equivalence, especially reordering of non-interfering expressions for parallelization or compiler optimization.

Source: Proceedings of the ACM on Programming Languages

DOI: 10.1145/3763116

Authors: Yuyan Bao, Songlin Jia, Guannan Wei, Oliver Bračevac, Tiark Rompf

Institutions: Augusta University, Purdue University West Lafayette, Tufts University, École Polytechnique Fédérale de Lausanne

Language: English

Topic: Logic, programming, and type systems

Subfield: Artificial Intelligence

Field: Computer Science

Domain: Physical Sciences

Open Access status: diamond

Funders: National Science Foundation, VMware

Award: CRII: SHF: Theoretical Foundations of Verifying Function Values and Reducing Annotation Overhead in Automatic Deductive Verification