Quentin Carbonneaux
Software Engineer at Stealth
France
Summary
🤩
Rockstar🎓
Top SchoolQuentin Carbonneaux is a research scientist with 14 years of experience at the intersection of programming languages, performance engineering, and formal verification, currently working in Meta’s programming language research lab. He blends low-level systems expertise with formal methods—contributing to high-profile open-source projects like HHVM and Zstandard where he improved type-checking, error diagnostics, and compression performance. His background includes scalable natural language understanding work at Google and JIT/type-checking research from internships at Inria and Facebook, backed by advanced training from École des Ponts, Université Paris Diderot (MPRI) and a PhD in Computer Science from Yale. Quentin has a knack for clarifying complex systems through code and documentation, evidenced by technical writing for the Rocq prover and careful refactors that both simplify APIs and recover performance. Colleagues would point to his dual talent for rigorous theory and pragmatic optimization—making proofs and production systems both safer and faster.
14 years of coding experience
9 years of employment as a software developer
Master's degree (MPRI), Computer Science, Master's degree (MPRI), Computer Science at Université Paris CitéDoctor of Philosophy - PhD, Computer Science, Doctor of Philosophy - PhD, Computer Science at Yale UniversityEngineer's degree, Mathematics and Computer Science, Engineer's degree, Mathematics and Computer Science at École nationale des ponts et chaussées
Github Skills (24)
algorithms10
proof-assistant10
dependent-types10
compress10
hacking10
c1110
hhvm10
c1710
type-system10
php10
coq10
performance-optimization10
hashtable10
compression10
theorem-proving10
Programming languages (12)
Github contributions (5)
facebook/hhvm
Jun 2016 - Aug 2022
A virtual machine for executing programs written in Hack.
Role in this project:
Back-end Developer
Back-end DeveloperContributions:75 commits, 7 comments in 6 years 3 months
Contributions summary:Quentin primarily contributed to the improvement of the HHVM virtual machine, specifically focusing on error messages and type-access related features within the Hack language. They fixed error messages for unsatisfiable constraints on constructors and cleaned up type access code by streamlining the expansion environment, removing unnecessary threading of data, and simplifying the create_root_from_type_constant function. The contributions indicate a focus on improving the type-checking and the overall efficiency of the Hack language.
virtual-machinehhvmphphacklang
facebook/zstd
Jan 2021 - Feb 2021
Zstandard - Fast real-time compression algorithm
Role in this project:Back-end Developer / Performance Engineer
Back-end Developer / Performance EngineerContributions:4 reviews, 8 commits, 2 PRs in 1 month
Contributions summary:Quentin focused on improving the performance and efficiency of the Zstandard compression algorithm. They implemented several performance improvements within the "ldm" (long distance matching) algorithm, specifically addressing code related to hash table management, sequence generation, and rolling hash computations. These changes included optimizing the hash table, improving the sequence generation process, and correcting implementation details. They also worked on refactoring code and fixing compiler warnings to increase code quality.
compression-algorithmzstandard
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