[clang] [PATCH 1/6] [clang] Improve nested name specifier AST representation (PR #147835)

[Erich Keane via cfe-commits]

https://github.com/erichkeane approved this pull request.

I did as thorough of a review as I could.  a small nit, else this is LGTM once the other reviewers who have commented are happy.

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