[clang] [clang-tools-extra] [clang] Improve nested name specifier AST representation (PR #147835)

[Matheus Izvekov via cfe-commits]

mizvekov wrote:

> Thanks! However, for the following piece of code
> `getOriginalDecl()` called on the pointed-to type gives the forward-declaration from the 3rd line, and the forward-declaration from the 1st line for its canonical type.

Yes that is correct.

The 3rd line is what declaration was found by type lookup at that point, and the canonical declaration has long been established in clang as the first declaration.

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