Jukka Lehtosalo

> Unfortunately TypeChecker cannot parse type expressions itself; only the earlier SemanticAnalyzer pass can do that. What are the reasons for this? Maybe we can adjust something to make it...

And thanks for working on this! This will be a useful feature, and will enable many new use cases.

> Again, if TypeChecker could parse a type expression itself there would be no need to store a parsed Type on an Expression (subclass) at all. I'm no longer sure...

Here is some more brainstorming, mainly about how to make the current approach more efficient. 1. `NameExpr` and `MemberExpr` (for things like `int` and `typing.Any`) can be resolved to type...

> I investigated whether a TypeAnalyzer could be created inside the TypeChecker pass. This may be impractical, since symbol tables for local variables (including type aliases) are only available during...

The release will likely be based on commit 8241059c14f99ad750ae3ac0de6a4795bf990f61 from Jun 11.

We have some basic documentation now, but various corner cases should still be documented in more detail.

It looks like the errors coming from CPython and psutil? ``` python: Objects/typeobject.c:3129: _PyType_Lookup: Assertion `!PyErr_Occurred()' failed. ... ImportError: /home/runner/work/mypy/mypy/.tox/py/lib/python3.8/site-packages/psutil/_psutil_linux.abi3.so: undefined symbol: PyModule_Create2 ``` I wonder if the tests would...

We are working on supporting metaclasses, with some performance penalty. The idea is to make it possible to explicitly request some classes to be non-extension classes. These classes could then...

python/mypy#5423 was fixed but this is still happening. The best course of action may be to accept the `None` type.