[libcxx-commits] [libcxx] [libc++] Implement P0429R9 `std::flat_map` (PR #98643)

[A. Jiang via libcxx-commits]

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@@ -137,6 +137,11 @@ _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR __exception_guard<_Rollback> __make_exce
   return __exception_guard<_Rollback>(std::move(__rollback));
 }
 
+template <class _Rollback>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR __exception_guard_exceptions<_Rollback> __make_scoped_guard(_Rollback __rollback) {
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frederick-vs-ja wrote:

I guess `_LIBCPP_CONSTEXPR_SINCE_CXX20` should be used. Or perhaps we can use plain `constexpr` and guard this with `_LIBCPP_STD_VER >= 23`?

https://github.com/llvm/llvm-project/pull/98643