I doubt those languages would have the same level of traction as Rust, especially now that Rust has already gotten said traction over the past decade with even the Linux kernel using them. It's more likely that Rust will be written as today and then these extra features are added for more type safety in certain functions as like I said in another comment I doubt people are going to write type contracts for every single function (maybe LLMs will, but that's an orthogonal discussion).