test_json results in stack overflow after the commit to implement __repr__ for weakset. This is very much similar to the one consistently occurring on my inspect module PR in Windows tests only for the past two weeks. My change was in changing inspect module and more specifically in importing ast at the top of inspect module. The relevant commit for buildbot failure is in implementing __repr__ for weakset.

Buildbot error : https://buildbot.python.org/all/#/builders/12/builds/2497

Error in my PR that is consistent and same : https://ci.appveyor.com/project/python/cpython/builds/24631185#L1547