[clang] [PATCH 1/7] [clang] Improve nested name specifier AST representation (PR #147835)

[Yanzuo Liu via cfe-commits]

zwuis wrote:

I added comment `// FIXME (GH147000): duplicate diagnostics` to `clang/test/SemaCXX/nested-name-spec.cpp` in #147003. Please remove the comment if that issue is fixed by this patch.

https://github.com/llvm/llvm-project/pull/147835