Designing Expressive Effect Systems

Par

Matthew Lutze

Aarhus University

Lundi 16 février 2026, 10:30-11:30 EST, Salle 6214

Pavillon André-Aisenstadt, Université de Montréal, 2920 Chemin de la Tour

Abstract: An effect system is a way for a programming language to track the possible actions taken by a program before the program is ever run. Information about effects is important for both security and optimization of code, as well as supporting programmers through built-in documentation. In this talk, I will introduce the concept of effect systems through the lens of the Flix programming language. I will cover the unique features of Flix's effect system, including effect exclusion (ICFP 2023) and associated effects (PLDI 2024), and then discuss some ongoing and future work in the domain.

Bio: Matthew Lutze is a postdoctoral researcher in the Programming Languages group at Aarhus University. Before earning his PhD at Aarhus in 2026, he earned his master's degree at Université Paris Cité in 2022. His research has covered several topics in programming language design and implementation, including effect systems, type inference, set-theoretic typing, and monomorphization, and has been published at top programming language venues including PLDI, POPL, ICFP, and OOPSLA. As a principal contributor to the Flix programming language, he has leveraged his research to implement several features for Flix's type and effect system.