Again, the ABI issue has nothing to do with editions. You can already build a binary today with three editions (though I forget if 2021 has any actual changes implemented yet) in the same executable. Part of the reason I said what I said is that every time we have this conversation you say you want to see how it plays out in practice, and we have shown you how multi-edition projects work, and how you can try it today, and you keep not listening. It’s FUD at this point.
It is different because those are frozen, editions are not (though in practice editions other than 2015 will rarely change). They make no guarantees about interop, and my understanding is that it might work, but isn’t guaranteed. If you have sources to the contrary I’d love to see them!
There is the similarity that the editions don't really matter for ABI, but otherwise editions are substantially different from the std switch.
C/C++ std switches freeze the entire language and disable newer features. Editions don't. Rust 2015 edition isn't an old version of Rust. It's the latest version of Rust, except it allows `async` as an identifier.
Editions don't really have an equivalent in C, but they're closer to being like trigraphs than the std compilation switch.
That only works because the Editions get updated after being released.
The same can happen to ISO C and C++, that is what technical revision documents are for.
> Therefore, the answer to the question of, say, “what is a valid C++14 program?” changes over time, up until the publication of C++17, and so forth. In practice, the situation is a bit more complicated when compiler vendors offer conformance modes for specific language revisions (e.g. -std=c++11, -std=c++17). Vendors may consider defect resolutions to apply to any historic revision that contains the defect (whereas ISO considers only the most recent publication as the Standard).
It is different because those are frozen, editions are not (though in practice editions other than 2015 will rarely change). They make no guarantees about interop, and my understanding is that it might work, but isn’t guaranteed. If you have sources to the contrary I’d love to see them!