[Lldb-commits] [lldb] [lldb] Fix expressions that involve nested structs/classes/unions. (PR #77029)

[Michael Buch via lldb-commits]

Michael137 wrote:

> So we never get a query again to find anything inside of this class. That being said, I am not sure anything ever was doing another external AST lookup in this class after we completed it. But if we are able to add debugger specific support into the external AST virtual interface, we might be able to gets asked "withing this 'class A' please find me a contained type" and then modify the compiler to use the external AST source when a lookup in a class decl context fails.

Right, what we want is for the `DeclContext::lookup` [here](https://github.com/llvm/llvm-project/blob/c6b5ea339d9f257b64f4ca468e447f0e29a909a4/clang/lib/Sema/SemaLookup.cpp#L1123-L1130) to consult LLDB, but it doesn't because the containing type was already marked as not having external storage. Haven't had the chance yet to look at what it would mean for us to drop the `setHasExternalLexicalStorage` calls with the current type-completion infrastructure, but [D101950](https://reviews.llvm.org/D101950) which we're trying to revive (where we pull definitions in more eagerly) gets rid of them

https://github.com/llvm/llvm-project/pull/77029