Given `int foo, bar;`, TraverseAST reveals this tree:
TranslationUnitDecl
- foo
- bar
Before this patch, with the TraversalScope set to {foo}, TraverseAST yields:
foo
After this patch it yields:
TranslationUnitDecl
- foo
Also, TraverseDecl(TranslationUnitDecl) now respects the traversal scope.
---
The main effect of this today is that clang-tidy checks that match the
translationUnitDecl(), either in order to traverse it or check
parentage, should work.
Differential Revision: https://reviews.llvm.org/D104071