[clang] [libcxx] [llvm] [Clang][CodeGen][Coroutines] Make coroutine startup exception-safe (CWG2935) (PR #177628)

[Yexuan Xiao via cfe-commits]

YexuanXiao wrote:

The failing test is unrelated to this PR; see https://github.com/llvm/llvm-project/issues/179006.

https://github.com/llvm/llvm-project/pull/177628