K Leino
Programming Language Designer Formal Verification Expert Tool Builder Writer And Teacher
Bellevue, Washington, United States
Summary
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Rockstar🎓
Top SchoolK Leino is a programming language designer and formal verification expert with over a decade of experience building verification-aware tools and compilers. After a long research and engineering career spanning Microsoft, Compaq/DEC, and AWS, he now works independently designing languages, tools, and teaching verified software engineering. He has contributed core back-end and compiler work to prominent verification projects like Dafny and Boogie—adding JavaScript compilation support, runtime type descriptors for generics, let expressions, and solver-robust fixes. His profile blends deep theory (PhD in CS from Caltech) with practical system-building and production-grade verifier engineering. As a published teacher and co-instructor at MIT, he translates formal methods into usable curricula and tools that developers can adopt. Outside work he balances hacker-level coding with a lively personal side, summed up aptly as “lover by day, hacker by night.”
10 years of coding experience
33 years of employment as a software developer
Bachelor of Arts (BA) with Special Honors in Computer Science, Computer Science, Bachelor of Arts (BA) with Special Honors in Computer Science, Computer Science at The University of Texas at AustinCalifornia Institute of Technology
Github Skills (10)
language-design10
compiler-development10
text-parsing9
parsing9
code-optimization8
data-structure7
data-structures7
algorithm7
algorithms7
javascript7
Programming languages (13)
Github contributions (5)
dafny-lang/dafny
Sep 2017 - Jan 2023
Dafny is a verification-aware programming language
Role in this project:
Back-end Developer
Back-end DeveloperContributions:13 releases, 1126 reviews, 724 commits in 5 years 4 months
Contributions summary:K appears to be working on the core functionality of the Dafny programming language, based on the commit messages and code changes. They were involved in removing machine-local output from previous commits and adding support for JavaScript compilation, specifically by introducing "run-time type descriptors" for generics and compiling extern statements. They also contributed to compiler optimizations.
compilerdafnyprogramming-languageverification
boogie-org/boogie
Jul 2018 - Aug 2021
Boogie
Role in this project:Back-end Developer & System Architect
Back-end Developer & System ArchitectContributions:73 reviews, 31 commits, 41 PRs in 3 years 2 months
Contributions summary:K contributed to the Boogie project, a program verifier, by addressing Z3 version dependencies and improving test output. They implemented let expressions in the Boogie language, enhancing its expressiveness. Additionally, the user fixed lambda-lifting issues, which involved correcting how free variables are computed and how holes are replaced in triggers. The contributions include changes to the parser, core language features, and model parsing, and include work on making the verifier robust to the characteristics of different SMT solvers.
boogie
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