SPLASH 2025
Sun 12 - Sat 18 October 2025 Singapore
co-located with ICFP/SPLASH 2025
Fri 17 Oct 2025 13:45 - 14:00 at Orchid West - Type 1 Chair(s): Lionel Parreaux

In many programming paradigms, some program entities are only valid within delimited regions of the program, such as resources that might be automatically deallocated at the end of specific scopes. Outside their live scopes, the corresponding entities are no longer valid – they are permanently invalidated. Sometimes, even within the live scope of a resource, the use of that resource must become temporarily invalid, such as when iterating over a mutable collection, as mutating the collection during iteration might lead to undefined behavior. However, high-level general-purpose programming languages rarely allow this information to be reflected on the type level. Most previously proposed solutions to this problem have relied on restricting either the aliasing or the capture of variables, which can reduce the expressiveness of the language. In this paper, we propose a higher-rank polymorphic type-and-effect system to statically track the permanent and temporary invalidation of sensitive values and resources, doing so without any aliasing or capture restrictions. We use Boolean-algebraic types (unions, intersections, and negations) to precisely model the side effect of program terms and guarantee they are invalidation-safe. Moreover, we present a complete and practical type inference algorithm, whereby programmers only need to annotate the types of higher-rank and polymorphically-recursive functions. Our system, nicknamed InvalML, has a wide range of applications where tracking invalidation is needed, including stack-based and region-based memory management, iterator invalidation, data-race-free concurrency, mutable state encapsulation, type-safe exception and effect handlers, and even scope-safe metaprogramming.

Fri 17 Oct

Displayed time zone: Perth change

13:45 - 15:30
Type 1OOPSLA at Orchid West
Chair(s): Lionel Parreaux HKUST (The Hong Kong University of Science and Technology)
13:45
15m
Talk
A Lightweight Type-and-Effect System for Invalidation Safety: Tracking Permanent and Temporary Invalidation With Constraint-Based Subtype Inference
OOPSLA
Cunyuan Gao HKUST, Lionel Parreaux HKUST (The Hong Kong University of Science and Technology)
DOI
14:00
15m
Talk
MTP: A Meaning-Typed Language Abstraction for AI-Integrated Programming
OOPSLA
Jayanaka Dantanarayana University of Michigan, Yiping Kang University of Michigan, Kugesan Sivasothynathan Jaseci Labs, Christopher Clarke University of Michigan, Baichuan Li University of Michigan, Savini Kashmira University of Michigan, Krisztian Flautner University of Michigan, Lingjia Tang University of Michigan, Jason Mars University of Michigan
14:15
15m
Talk
Modeling Reachability Types with Logical Relations -- Semantic Type Soundness, Termination, Effect Safety, and Equational Theory
OOPSLA
Yuyan Bao Augusta University, Songlin Jia Purdue University, USA, Guannan Wei Tufts University, Oliver Bračevac EPFL, LAMP, Tiark Rompf Purdue University
14:30
15m
Talk
Qualified Types with Boolean Algebras
OOPSLA
Edward Lee University of Waterloo; University of Toronto Scarborough, Jonathan Lindegaard Starup , Ondřej Lhoták University of Waterloo, Magnus Madsen Aarhus University
14:45
15m
Talk
RestPi: Path-Sensitive Type Inference for REST APIs
OOPSLA
Mark W. Aldrich Tufts University, Kyla H. Levin University of Massachusetts Amherst, USA, Michael Coblenz University of California, San Diego, Jeffrey S. Foster Tufts University
15:00
15m
Talk
Type-Outference with Label-Listeners: Foundations for Decidable Type-Consistency for Nominal Object-Oriented Generics
OOPSLA
Ross Tate Independent Researcher and Consultant
DOI Pre-print
15:15
15m
Talk
Type-Preserving Flat Closure Optimization
OOPSLA
Adam T. Geller University of British Columbia, Sean Bocirnea University of British Columbia, Chester Gould University of British Columbia, Paulette Koronkevich University of British Columbia, William J. Bowman University of British Columbia
DOI