C++20 actually [changed the semantics of consume](https://devblogs.microsoft.com/oldnewthing/20230427-00/?p=10...), but Rust doesn't include it. And last I remember compilers still treat it as acquire, so it's not worth the bytes it's stored in.

In the current drafts of C++ (I don't know which version it landed in), memory_order::consume is fully dead and listed as deprecated in the standard.