[charliermarsh]

Woah, Pyright is written in Node? And it has its own [parser](https://github.com/microsoft/pyright/blob/b74be3b2cb2c5d35b9...)? That's really interesting. I wonder how it compares to Mypy on speed.

> The main thing that eventually forced decision was a flaky (depends on cache) mypy crash using paramspecs half a year ago. At time paramspec support was still in progress and there’s a good chance that specific issue is fixed.

I actually think I ran into this exact issue (ParamSpec-related, only fails when reading from cache, etc.), which led me to pin a Mypy development version for a while and was fixed recently.

[anuragsoni]

> I wonder how it compares to Mypy on speed.

I use pyright at work at my current job, and used mypy at my previous job. Pyright has been better in almost every aspect in my experience. Its been more robust, and performs a lot better than mypy at type-checking in a fairly large mono-repo.