CFP: Workshop on the Implementation of Type Systems (WITS) '24

Call for contributions

3rd Workshop on the Implementation of Type Systems: WITS 2024
January 20, 2024
London, United Kingdom

WITS 2024 is the third Workshop on the Implementation of Type Systems. The
workshop will be held on January 20, 2024, in London, United Kingdom, co-located
with POPL. The goal of this workshop is to bring together the implementors of a
variety of languages with advanced type systems. The main focus is on the
practical issues that come up in the implementation of these systems, rather
than the theoretical frameworks that underlie them. In particular, we want to
encourage exchanging ideas between the communities around specific systems that
would otherwise be accessible to only a very select group.

The workshop will have a mix of invited and contributed talks, organized
discussion times, and informal collaboration time.


We invite participants to share their experiences, study differences among the
implementations, and generalize lessons from those. We also want to promote the
creation of a shared vocabulary and set of best practices for implementing type

Here are a few examples of topics we are interested to discuss:

  • syntax with binders and substitution
  • conversion modulo beta and eta
  • implicit arguments and metavariables
  • unification and constraint solving
  • metaprogramming and tactic languages
  • editor integration and automation
  • discoverability of language features
  • pretty printing and error messages

This list is not exhaustive, so please contact the PC chairs in case you are
unsure if a topic falls within the scope of the workshop.


WITS solicits two kinds of submissions:

  • Contributed talks on the basis of an abstract. This can be on recently
    published or submitted work, work in progress, or a project that is still in
    the idea phase.

  • Proposals for roundtable discussions. This can be on any topic within the
    scope of the workshop, but should have a broader scope than a contributed
    talk. If accepted, you will be in charge of leading a discussion of 45 minutes
    around the proposed topic together with other interested attendees.

Both kinds of proposals should be accompanied by an abstract of max. 1 page
(exclusive of references), formatted according to the guidelines for SIGPLAN
conferences: use the sigplan option to the acmart LaTeX document class. WITS
will have no published proceedings, so submitting to WITS does not interfere
with submission (before, after, or simultaneously) with other
venues. Submissions are handled via

Important Dates

  • Abstract submission deadline: 10 November, 2023 (AoE)
  • Notification: 1 December, 2023
  • Workshop in London: 20 January, 2024

Attendance and registration

WITS 2024 is colocated with POPL 2024 in London, UK. Information
on registration and attendance will be posted on the POPL website

Program Committee

Lennart Augustsson      Epic Games, Sweden
Edwin Brady             St. Andrews, UK
Jesper Cockx            TU Delft, Netherlands   co-chair
Richard Eisenberg       Jane Street, USA        co-chair
Jacques-Henri Jourdan   CRNS, France
Matthieu Sozeau         INRIA, France
Ningning Xie            U. of Toronto, Canada
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