About

I am an incoming Assistant Professor in the Department of Computer Science at the University of Toronto in Fall 2023.
From Fall 2022, I will also work as a research scientist at Google Brain.
Currently, I am a research associate at University of Cambridge. I finished my Ph.D. in the Programming Languages Group at University of Hong Kong in 2021.

I'm actively looking for self-motivated Ph.D. students. Please take a look at this link if you're interested.

News

• (Pinned) I am currently on the program committee of HOPE 2022, ML 2022, ICFP 2022, SPLASH 2022 SRC, and POPL 2023. Please consider submitting a paper!

• 2022 July New paper conditionally accepted at OOPSLA 2022.

• 2022 May New paper accepted at ECOOP 2022.

• 2022 Jan New paper accepted at MLSys 2022.

• 2021 Nov New paper accepted at PEPM 2022.

• 2021 Sept New work accepted at POPL 2022.

Publications

• First-class Names for Effect Handlers
  Ningning Xie, Youyou Cong, Kazuki Ikemori, Daan Leijen
  OOPSLA 2022 (conditionally accepted)

• Union Types with Disjoint Switches
  Baber Rehman, Xuejing Huang, Ningning Xie, Bruno C. d. S. Oliveira
  ECOOP 2022 [doi] [paper]

• Synthesizing Optimal Parallelism Placement and Reduction Strategies on Hierarchical Systems for Deep Learning
  Ningning Xie, Tamara Norman, Dominik Grewe, Dimitrios Vytiniotis
  MLSys 2022 [url] [paper]

• Staging with Class: A Specification for Typed Template Haskell
  Ningning Xie, Matthew Pickering, Andres Löh, Nicolas Wu, Jeremy Yallop, Meng Wang
  POPL 2022 [doi] [paper] [appendix] [slides]

• Generalized Evidence Passing for Effect Handlers: Efficient Compilation of Effect Handlers to C
  Ningning Xie, Daan Leijen
  ICFP 2021 [doi] [paper] [technical report] [slides] [Haskell implementation] [mpeff on Hackage] [artifact]

• Perceus: Garbage Free Reference Counting with Reuse
  Ningning Xie*, Alex Reinking*, Leonardo de Moura, Daan Leijen (*Equal contributions)
  PLDI 2021 [doi] [paper] [technical report] [slides] [artifact]
  ACM SIGPLAN Distinguished Paper Award

• Effect Handlers in Haskell, Evidently.
  Ningning Xie, Daan Leijen
  Haskell 2020 [doi] [paper] [slides] [Haskell implementation] [eveff on Hackage]

• Effect Handlers, Evidently.
  Ningning Xie, Jonathan Brachthäuser, Daniel Hillerström, Philipp Schuster, Daan Leijen
  ICFP 2020 [doi] [paper] [technical report] [slides]

• Kind Inference for Datatypes.
  Ningning Xie, Richard A. Eisenberg, Bruno C. d. S. Oliveira
  POPL 2020 [doi] [paper] [slides] [appendix]
  ACM SIGPLAN Distinguished Paper Award

• Row and Bounded Polymorphism via Disjoint Polymorphism.
  Ningning Xie, Bruno C. d. S. Oliveira, Xuan Bi, Tom Schrijvers
  ECOOP 2020 [doi] [paper] [appendix] [slides] [Coq proof] [poster]

• Consistent Subtyping for All.
  Ningning Xie, Xuan Bi, Bruno C. d. S. Oliveira, Tom Schrijvers
  ACM Transactions on Programming Languages and Systems 2020
  [doi] [paper] [slides] [Coq proof, Haskell implementation]

• Coherence of Type Class Resolution.
  Gert-Jan Bottu, Ningning Xie, Koar Marntirosian, Tom Schrijvers
  ICFP 2019 [doi] [paper] [appendix]

• Distributive Disjoint Polymorphism for Compositional Programming.
  Xuan Bi, Ningning Xie, Bruno C. d. S. Oliveira, Tom Schrijvers
  ESOP 2019 [doi] [paper] [slides] [Coq proof, Haskell implementation] [poster]

• Consistent Subtyping for All.
  Ningning Xie, Xuan Bi, Bruno C. d. S. Oliveira
  ESOP 2018 [doi] [paper] [slides] [Coq proof, Haskell implementation]
  Selected for Special Issue of ACM Transactions on Programming Languages and Systems
  

• Let Arguments Go First.
  Ningning Xie, Bruno C. d. S. Oliveira
  ESOP 2018 [doi] [paper] [appendix] [slides] [Coq proof]

Workshop

• Parallel Algebraic Effect Handlers
  Ningning Xie*, Daniel D. Johnson*, Dougal Maclaurin, Adam Paszke (*Equal contributions)
  ACM SIGPLAN Workshop on Partial Evaluation and Program Manipulation 2022 [pdf] [Arxiv]

• First-class Names for Effect Handlers
  Ningning Xie, Youyou Cong, Daan Leijen
  ACM SIGPLAN Workshop on Higher-Order Programming with Effects 2021 [extended abstract]

• Coercion Quantification.
  Ningning Xie, Richard A. Eisenberg
  Haskell Implementors' Workshop 2018 [extended abstract] [slides] [Haskell implementation]

• Towards Unification for Dependent Types.
  Ningning Xie, Bruno C. d. S. Oliveira
  Trends in Functional Programming 2017 [extended abstract] [slides]

Dissertation

• Higher-rank Polymorphism: Type Inference and Extensions.
  Ph.D. Dissertation. 2021. [thesis]
  Advisor: Bruno Oliveira. External committee: Simon Peyton Jones.

Service

• Steering Committee: Haskell Symposium (2020 - 2023).
• Special Session Organizer: MFPS 2022.
• Program Chair: Haskell Implementor's Workshop 2021.
• Program Committee: Haskell Implementors' Workshop 2019. Haskell 2019. PADL 2021. FLOPS 2022. TFP 2022. ICFP 2022. Scala 2022. HOPE 2022. ML 2022. SPLASH SRC 2022. POPL 2023.
• Artifact Evaluation Committee: ICFP 2019. PLDI 2020.
• Sub-Reviewer: APLAS 2016, 2017. ESOP 2017. FLOPS 2018. ECOOP 2019. ICFP 2019.
• Student Volunteer: APSys 2016. PLDI 2018. ICFP 2018. ETAPS 2019.

Mentoring

• Panelists. PLMW @ PLDI 2022.
• Long-term Mentor. SIGPLAN-M.
• Mentor. PLMW @ POPL 2021.
• Mentor. PLMW @ SPLASH 2020.

Teaching

• Tutorial. Programming with Effect Handlers and FBIP in Koka. ICFP 2021. Aug 2021.
• Instructor. Haskell 101. Google, New York City. November 2019.
• Teaching Assistant. Principles of Programming Languages. The University of Hong Kong. Spring 2019.
• Teaching Assistant. Functional Programming. The University of Hong Kong. Fall 2017.

Misc

• Literature Review of GHC Core. June 2018.
• I was a funded participant of DeepSpec Summer School 2017.
• I passed Japanese-Language Proficiency Test N2. 日本語能力試験N2に合格しました。2016.
• Software Foundations, Chinese edition.