I’m a big fan of how C# handles this. The standard library is versioned like any other library. Your program is explicit about the major version of the standard library you’re pulling in. And all major versions of the standard library continue to work.

For rust, this would mean something like adding std = 1.0.6 to your cargo.toml. The advantage is it means the standard library can deprecate and replace features. Upgrading std is an explicit step by the developer. Annoying, but in the age of LLMs it should be pretty easy.

The one big question I can’t answer is what happens if your dependencies use a different version of std? Are std v1 Strings compatible with std v2 strings? Oof.