Tracking those can help to provide much better diagnostics in many cases.
In general, most of the visitor machinery should be refactored to allow
tracking the origin of arbitrary values.
rdar://36039765
Differential Revision: https://reviews.llvm.org/D51131
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@340475 91177308-0d34-0410-b5e6-96231b3b80d8
George Karpenkov