## Summary Implement linear-time variance inference for type variables (https://github.com/astral-sh/ty/issues/488). Inspired by Martin Huschenbett's [PyCon 2025 Talk](https://www.youtube.com/watch?v=7uixlNTOY4s&t=9705s). ## Test Plan update tests, add new tests, including for mutually recursive classes --------- Co-authored-by: Carl Meyer <carl@astral.sh>
Markdown files within the mdtest/ subdirectory are tests of type inference and type checking;
executed by the tests/mdtest.rs integration test.
See crates/ty_test/README.md for documentation of this test format.