Rust 1.100 Arrives November 12 With Major Type And Cargo Changes
The upcoming Rust 1.100 release introduces the never type and updates the Cargo directory structure, prompting developers to test their projects against the beta channel.
Rust 1.100 launches on November 12. You can test your projects against the beta channel right now using cargo +beta test to catch compatibility issues ahead of the stable release.
Version 1.100 brings more breaking changes than standard minor updates, despite the team's backward compatibility efforts.
The main change is the stabilization of the never type. The compiler's type inference now infers certain expressions as the never type ! instead of the unit type (). If your codebase used workarounds for the never type on stable versions, you might see failures. This happens because the Infallible type now acts as an alias for the never type.
Cargo's directory layout also changes in this version. Target directory structure modifications can break build scripts and auxiliary tools that rely on specific file locations. Since these updates impact both primary project code and external dependencies, you need to verify your toolchains.
Running your current builds in the beta environment isolates problems caused by the new type inference rules and file structure changes before production workflows run into them. Technical pull requests and project documentation contain further details on these language and tool updates.