[clang] [clang] Instantiate attributes on other decl types (PR #115924)

[Eric Astor via cfe-commits]

ericastor wrote:

> Still need tests for namespacealiasdecl, typedefnamedecl, and typealiastemplatedecl actually being instantiated.
> 
> Also, is there a reason why the only way to currently test these are with the plugins? I would expect there to be SOME builtin attribute that could be validated for all of those as well.

Since I'm not fully familiar with all of the attributes that could be applied to those decls, I'm withdrawing those parts of this PR for now. I'll be happy to help with those separately.

I'll look into whether I can test it without using plugins, but I first wanted to get *any* test working with LabelDecl, and (as mentioned) I wasn't sure what built-in attributes would apply. I'll follow up with more tests.

https://github.com/llvm/llvm-project/pull/115924