@Yurii, I would like to caution against a C accelerator for the typing module. My reasoning follows:

1. The maintenance burden is higher. typing is already somewhat complex in Python (lots of MRO/metaclass wizardry). A C module would require knowledge of the C API.

2. Following from 1., I fear it may raise the barrier for contributions. This is purely anecdotal but I think there are more contributors who know Python than Python + C API.

3. C API code is much more error-prone than Python code.

4. It's very hard to find available reviewers for typing-related C changes.

5. Backports become harder due to point 3. and 4. Also C code needs much more scrutiny. If we cause some obscure bug in Python, it raises an exception; in C it potentially segfaults and kills the interpreter.

6. Third-party monkey-patching becomes harder.

Unfortunately, I can't offer a good solution to this issue at the moment either.