No one knows, and I don't think there's been (a public) discussion about it by projects leads. The only guarantee is that 1.x will not break anything (according to some definition of "break").
There needs to be more experience with widespread use and multiple releases, to see how far that backcompat can be held. Perhaps after 10 releases, it should be a lot more clear whether or not a Rust 2.0 will be needed.
There needs to be more experience with widespread use and multiple releases, to see how far that backcompat can be held. Perhaps after 10 releases, it should be a lot more clear whether or not a Rust 2.0 will be needed.