Waleed Khan

Compiler engineer on the Scala Language & Tools team. Visiting engineer on Source Control team.

• Led team of 4 to develop tool to manage Git sparse checkouts derived from Bazel.
  • Presented at Git Merge 2022.
  • Typical git status time: 3sec → 200ms.
• Migrated compiler rulesets, code generation pipelines from Pants to Bazel.
• Integrated formatting and linting tooling into command-line workflows.

Compiler engineer working on improving the scalability of the Hack programming language.

• Formalized and proved the correctness of Hack's incremental typechecking algorithm.
• Migrated Hack to use the Language Server Protocol, providing support for all major editors.
• Developed a linting system for Hack code written in Hack itself, now supporting hundreds of lint rules.
• Developed a refactoring system suitable for monorepo-scale code migrations. Typical job time: 12hr → 15min.
• Developed low-latency IDE server. Worst-case startup time: 5min → 10sec.

• Created "stacked diffs" dependency graph visualization for Phabricator code review tool.

• Developed alerting for upcoming large-scale pre-order release events in order to provision machines preemptively.

• Streamlined automatic-grading web application. Core workflow: 6 clicks → 1 click.

Monorepo-scale workflow for Git, based off of the Mercurial workflows at companies like Google and Facebook.

ML email bot which detects unsolicited recruiter email and responds with compensation/leveling requirements.

Spaced-repetition training app for the fighting game Super Smash Bros. Ultimate. Approximately 200 monthly users.