From the end of the safety document:
> Overall, Carbon is making a compromise around safety in order to give a path for C++ to evolve. C++ developers must be comfortable migrating their codebases, and able to do so in a largely automated manner. In order to achieve automated migration, Carbon cannot require fundamental redesigns of migrated C++ code. While a migration tool could in theory mark all migrated code as unsafe, Carbon should use a safety strategy that degrades gracefully and offers improvements for C++ code, whether migrated or not.
> That does not mean Carbon will never adopt guaranteed safety by default, only that performance and migration of C++ code takes priority, and any design will need to be considered in the context of other goals. It should still be possible to adopt guaranteed safety later, although it will require identifying a migration path.
That's very interesting and pragmatic. It would be interesting if they can eventually come up with the same level of safety guarantees via a different path than Rust's borrow checker.
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Since one of their goals is to automatically translate modern C++ to Carbon, I do wonder how well that is going to work in general.
I definitely welcome an alternative to C++ that would be easier to read and understand. That would be a benefit to the world.