About

I finished my Ph.D. in the Programming Language Group at University of Hong Kong. Before that, I obtained my B.S. (with Honors) from Zhejiang Unversity.
I had the pleasure to work with a lot of amazing people during my Ph.D. journey. Check out my wonderful collaborators!
I am a former research intern at the RiSE team at Microsoft Research Redmond, and more previously a software engineer intern at Google Search in New York City.
I am a steering committee member of the Haskell Symposium.

News

• 2021 July Will serve on the program committee of FLOPS 2022. Please consider submitting a paper!

• 2021 June New talk accepted at HOPE 2021.

• 2021 May Thrilled to share that Perceus won the ACM SIGPLAN Distinguished Paper Award at PLDI 2021.

• 2021 May New work conditionally accepted at ICFP 2021.

• 2021 April I defended my thesis!

• 2021 Mar Haskell Implementors' Workshop Call for talks is up! Please consider submitting your coolest ideas about Haskell implementations/libraries/etc!

• 2021 Mar New paper conditionally accepted at PLDI 2021.

• 2020 Nov Excited to serve as a mentor at PLMW @ SPLASH.

Publications

• Generalized Evidence Passing for Effect Handlers (or, Efficient Compilation of Effect Handlers to C)
  Ningning Xie, Daan Leijen
  ICFP 2021 [paper] [technical report] [artifact]

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

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

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

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

• 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

• 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]

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

• Consistent Subtyping for All.
  Ningning Xie, Xuan Bi, Bruno C. d. S. Oliveira, Tom Schrijvers
  TOPLAS [doi] [paper] [Coq proof, Haskell implementation]

• Consistent Subtyping for All.
  Ningning Xie, Xuan Bi, Bruno C. d. S. Oliveira
  ESOP 2018 [doi] [paper] [Coq proof, Haskell implementation]
  Selected for TOPLAS Special Issue
  

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

Dissertation

• Higher-rank Polymorphism: Type Inference and Extensions.
  Ph.D. Dissertation. [thesis]
  Committee: Bruno Oliveira (advisor), Sergio Lourenco (chair), Zhiyi Huang, Giulio Chiribella, Simon Peyton Jones (external)

Workshop Talks

• First-class Names for Effect Handlers
  Ningning Xie, Youyou Cong, Daan Leijen
  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]

Talks

• Perceus: Garbage Free Reference Counting with Reuse
  Invited talk. LFCS. The University of Edinburgh. Mar 2021. [slides]

• Type-based Language Design.
  Invited talk. Peking University. Dec 2020.
  Invited talk. JHC. Shanghai Jiao Tong University. Dec 2020.

• Inferring Datatypes.
  Lightning talk. Haskell Implementors' Workshop 2019. Aug 2019. [slides]

• Dependent Types in Haskell.
  Invited talk. Hong Kong Functional Programming Meetup. Dec 2018. [code] [slides]

• Consistent Subtyping for All.
  Invited talk. Penn PLClub. University of Pennsylvania. May 2018. [slides]

Service

• FLOPS 2022. Program Committee.
• Haskell Symposium. Steering Committee.
• Haskell Implementor's Workshop 2021. Program Chair.
• PADL 2021. Program Committee.
• Haskell Implementors' Workshop 2019. Program Committee.
• Haskell 2019. Program Committee.
• ICFP 2019. PLDI 2020. Artifact Evaluation Committee.
• APLAS 2016, 2017. ESOP 2017. FLOPS 2018. ECOOP 2019. ICFP 2019. Sub-Reviewer.
• APSys 2016. PLDI 2018. ICFP 2018. ETAPS 2019. Student Volunteer.

Mentoring

• PLMW@POPL 2021. Mentor.
• PLMW@SPLASH 2020. Mentor.

Teaching

• 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.
• Software Foundations, Chinese edition.