[Async-sig] Preventing `yield` inside certain context managers

[Nathaniel Smith]

This proposal might be of interest to folks here:
https://discuss.python.org/t/preventing-yield-inside-certain-context-managers/1091

I posted the main text there instead of here because it's a change to
the core interpreter, but the motivation is async APIs.

Probably best to post replies there, to keep the discussion consolidated.

-n

-- 
Nathaniel J. Smith -- https://vorpus.org