Currently the `bias` attribute of `torch.nn.Linear` (and `Bilinear`) is typed incorrectly, because it relies on the implicit `Module.__getattr__` which types it as `Tensor | Module`. This has two issues:
- It hides the fact that `bias` is optional, and can be `None`, which in turn can hide actual bugs on user side.
- It blurs the type due to having `Module` in the union, which can require unnecessary `isistance(linear.bias, Tensor)` on user side.
This PR types the `bias` attribute explicitly to fix these issues.
CC @ezyang @Skylion007
Pull Request resolved: https://github.com/pytorch/pytorch/pull/142326
Approved by: https://github.com/ezyang
Re-enable type checking for distributed_c10d.py
Type checking for distributed_c10d.py was inadvertently turned off in issues that have accumulated since.
Note: the backwards compatibility linter does not like some of these changes. But they were incorrect before. This needs human verification, however.
#suppress-api-compatibility-check
Pull Request resolved: https://github.com/pytorch/pytorch/pull/115223
Approved by: https://github.com/wconstab
