[clang] [Clang] A lone `[` does not an attribute make (PR #147306)

[Aaron Ballman via cfe-commits]

https://github.com/AaronBallman commented:

I think the old code was not handling Microsoft attributes and I think the new code is also not handling Microsoft attributes, just in a different way.

AIUI, Microsoft attributes are deprecated (https://godbolt.org/z/Ma45KKMvG) and only used on a declaration, thus they really don't need tentative parse disambiguation support. However, HLSL uses this style of attributes and I'm far less familiar with the usage there. @llvm-beanz do you know if HLSL has to worry about tentative parsing for these?

If not, then I think this LGTM.

https://github.com/llvm/llvm-project/pull/147306