Inside Facebook Mobile

Pyrefly is a faster, open-source Python type checker written in Rust, succeeding Pyre. But what prompted the rewrite and what besides the language choice ended up making it faster? Host Pascal talks to Maggie, Rebecca and returning guest Neil about the unexpected complexities of building an incremental type checker that scales to mono repositories in episode 75. Got feedback? Send it to us on Threads (https://threads.net/@metatechpod), Instagram (https://instagram.com/metatechpod) and don’t forget to follow our host Pascal (https://mastodon.social/@passy, https://threads.net/@passy_). Fancy working with us? Check out https://www.metacareers.com/. Links Pyrefly: https://pyrefly.org/ Pyre: https://pyre-check.org/  Ruff: https://github.com/astral-sh/ruff  PEP 484: https://peps.python.org/pep-0484/  Timestamps Intro    0:06 Rebecca Introduction    1:45 Maggie Introduction    2:45 Neil (Re-)Introduction    3:12 Team Mission    3:56 History of Typing in Python    4:29 The State of Typed Pyth