[libcxx-commits] [libcxx] [libc++] Diagnose unused variables of container types (PR #203084)

[Denis Yaroshevskiy via libcxx-commits]

DenisYaroshevskiy wrote:

This will cause us a lot of hassle because it causes "Unused variable" warning to start firing in many more places then it was before.

The only option for us, with this change, would be to disable the "unused variable" warning because the impact will be very widespread.

We'd appreciate it If you had introduced a macro instead of using `[[__gnu__::__warn_unused__]]` directly, so that we could keep the existing warnings, while disabling these ones with a targeted fix, hopefully temporarily. 

https://github.com/llvm/llvm-project/pull/203084