Fengyun Liu
Senior Researcher at Oracle
Lausanne, Vaud, Switzerland
Summary
🤩
Rockstar🎓
Top SchoolFengyun Liu is a Senior Researcher and compiler engineer with 14 years of experience building language tools and developer-facing platforms, currently working on GraalVM at Oracle. He has deep expertise in the Scala ecosystem—contributing to the Scala 3 compiler, porting ScalaTest and plugin systems to Dotty, and improving pattern matching, inlining, and Java interop—alongside notable open-source work on sbt and other widely used projects. His background blends academic rigor (EPFL PhD) with hands-on product experience from running a Rails studio and shipping backend systems, giving him a rare combination of formal-methods thinking and pragmatic engineering. He often tackles subtle correctness and compatibility issues—such as compiler macros, exhaustivity checks, and binary compatibility—making compilers and tooling both safer and more usable. Based in Lausanne, he pairs research-led solutions with production-grade contributions to major community projects.
14 years of coding experience
9 years of employment as a software developer
Bachelor, Software Engineering, Bachelor, Software Engineering at 南京大学Master's degree, Informatik, Master's degree, Informatik at Ecole polytechnique fédérale de Lausanne
English, French
Stackoverflow
101reputation
75kreached
2answers
0questions
Github Skills (41)
debug10
benchmark10
graalvm10
back-end-development10
testing10
macros10
compiler-plugin10
sbt10
benchmarking10
rails10
test-framework10
refactor10
java10
scala10
dotty10
Programming languages (9)
Github contributions (5)
ari/jobsworth
Oct 2011 - Jan 2013
Project Management, Collaboration and Time Tracking.
Role in this project:
Back-end Developer
Back-end DeveloperContributions:864 commits in 1 year 3 months
Contributions summary:Fengyun primarily focused on migrating and upgrading the project's codebase. They implemented new asset management techniques using Rails 3.1 sprockets-style and refactored various parts of the application, including code related to tasks, milestones and emails. They also addressed and fixed several bugs, including those related to the handling of user permissions, the display of time estimates, and resolving potential issues with task dependencies. The user also adjusted database schema and resolved some deployment related problems.
collaborationtime-trackingtrackingproject-planningrefactoring
scala/scala3
Mar 2016 - Dec 2022
The Scala 3 compiler, also known as Dotty.
Role in this project:Back-end Developer
Back-end DeveloperContributions:1233 reviews, 1984 commits, 1029 PRs in 6 years 9 months
Contributions summary:Fengyun contributed to the Scala 3 compiler, primarily by fixing issues related to inline accessors, the ReplPrinter, and the reflect API. The commits demonstrate a focus on improving code generation, resolving type-related problems, and enhancing the printing functionality within the compiler. The user also implemented changes to better support language features, such as the handling of union types and the inclusion of Java interop features.
compilerscala3scaladottyepfl
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