You've probably used a Python type checker or language server—but have you ever looked under the hood to see how they're built? Join a guided tour with one of the authors of ty, a fast Python type checker and language server. We'll explore the challenges of Python type checking: what it takes to provide detailed contextual diagnostics, responsive fine-grained incremental re-checking as you type, control-flow-sensitive type narrowing, gradual typing, and set-theoretic types (unions, intersections, and negations) — and keep it all running snappily.
An extensive community of contributors has helped build ty. By the end of this talk, you'll have the foundations to become the next contributor, or a ty user with a better understanding of your tools.