With the understanding that you can have multiple specs if one is entirely more permissive than the other (and as such, programmers must conform to the least permissive spec, that is, the spec that allows the smallest number of things)
But the problem is, Rust doesn't even have this least permissive spec. Or any other.
It does not, and at the current pace, it might never have a spec.
The reason there is no spec - not even an hypothetical spec in my head - is that the exact semantics of Rust has not been settled.
With the constraints the Rust project are operating with, the only way forward I can think of is following the ideas laid out in post
https://faultlore.com/blah/tower-of-weakenings/
With the understanding that you can have multiple specs if one is entirely more permissive than the other (and as such, programmers must conform to the least permissive spec, that is, the spec that allows the smallest number of things)
But the problem is, Rust doesn't even have this least permissive spec. Or any other.