ECOOP 2020
Sun 15 - Tue 17 November 2020 Online Conference
co-located with SPLASH 2020
Mon 16 Nov 2020 06:00 - 06:20 at SPLASH-I - S-6 Chair(s): Jeremy Gibbons, Olivier Flückiger
Sun 15 Nov 2020 18:00 - 18:20 at SPLASH-I - S-6 Chair(s): Shigeru Chiba, Tiark Rompf

The Scala programming language makes all reference types implicitly nullable. This is a problem, because null references do not support most operations that do make sense on regular objects, leading to runtime errors. In this paper, we present a modification to the Scala type system that makes nullability explicit in the types. Specifically, we make reference types non-nullable by default, while still allowing for nullable types via union types. We have implemented this design for explicit nulls as a fork of the Dotty (Scala 3) compiler. We evaluate our scheme by migrating a number of Scala libraries to use explicit nulls. Finally, we give a denotational semantics of type nullification, the interoperability layer between Java and Scala with explicit nulls. We show a soundness theorem stating that, for variants of System F omega that model Java and Scala, nullification preserves elements of ground types.

Sun 15 Nov
Times are displayed in time zone: Central Time (US & Canada) change

17:00 - 18:20: S-6Research Papers at SPLASH-I +12h
Chair(s): Shigeru ChibaThe University of Tokyo, Tiark RompfPurdue University
17:00 - 17:20
Talk
Research Papers
Julia GabetImperial College London, Nobuko YoshidaImperial College London
Link to publication DOI Media Attached
17:20 - 17:40
Talk
Research Papers
Vlastimil DortCharles University, Ondřej LhotákUniversity of Waterloo
Link to publication DOI Media Attached
17:40 - 18:00
Talk
Research Papers
Keigo ImaiGifu University, Rumyana NeykovaBrunel University London, Nobuko YoshidaImperial College London, Shoji YuenNagoya University
Link to publication DOI Media Attached
18:00 - 18:20
Talk
Research Papers
Abel NietoAarhus University, Yaoyu ZhaoUniversity of Waterloo, Ondřej LhotákUniversity of Waterloo, Angela ChangUniversity of Waterloo, Justin PuUniversity of Waterloo
Link to publication DOI Pre-print Media Attached

Mon 16 Nov
Times are displayed in time zone: Central Time (US & Canada) change

05:00 - 06:20: S-6Research Papers at SPLASH-I
Chair(s): Jeremy GibbonsDepartment of Computer Science, University of Oxford, Olivier FlückigerNortheastern University
05:00 - 05:20
Talk
Research Papers
Julia GabetImperial College London, Nobuko YoshidaImperial College London
Link to publication DOI Media Attached
05:20 - 05:40
Talk
Research Papers
Vlastimil DortCharles University, Ondřej LhotákUniversity of Waterloo
Link to publication DOI Media Attached
05:40 - 06:00
Talk
Research Papers
Keigo ImaiGifu University, Rumyana NeykovaBrunel University London, Nobuko YoshidaImperial College London, Shoji YuenNagoya University
Link to publication DOI Media Attached
06:00 - 06:20
Talk
Research Papers
Abel NietoAarhus University, Yaoyu ZhaoUniversity of Waterloo, Ondřej LhotákUniversity of Waterloo, Angela ChangUniversity of Waterloo, Justin PuUniversity of Waterloo
Link to publication DOI Pre-print Media Attached