Resubmit overload v2 (#31123)
Summary:
Resubmit of https://github.com/pytorch/pytorch/pull/30356 and https://github.com/pytorch/pytorch/pull/31014 :'(
The last commit contains the fix. There was an internal FBcode error not able to compile the previous `impl_default->second.equal(default_val.second))` line. I tried various fixes in C++ internally but couldn't figure anything out. This is a good example of the programming costs of going from python -> c++ for different types of objects, because the conceptual overhead has expanded in scope from (python) -> (python, c++, pybind).
Pull Request resolved: https://github.com/pytorch/pytorch/pull/31123
Differential Revision: D18936128
Pulled By: eellison
fbshipit-source-id: 7d8fd66a6dd4a3e9838f3a0b68c219b6565a9462
