[clang] [Serialization] Fix source location data loss during decoding. (PR #145529)

[Chuanqi Xu via cfe-commits]

ChuanqiXu9 wrote:

Yeah, and for what it worth, maybe you want to take a look at: https://discourse.llvm.org/t/rfc-c-modules-stop-using-abbrev-and-drop-the-maintainance/87063/2

https://github.com/llvm/llvm-project/pull/145529