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.