Rust 1.100 Released with Stabilized Never Type and Allocator API

Rust 1.100.0 has been released, marking the first time the version number reaches three digits. The most anticipated change is the stabilization of the never type (!) after about 10 years and five attempts, along with the stabilization of core parts of the Allocator API, bringing significant improvements in type system expressiveness and memory allocation control for systems developers.

The never type (!) denotes computations that never return, and with its stabilization, Infallible becomes an alias, enhancing the expression of unreachable branches. The Allocator API core is now stable, with Vec and Box supporting custom memory allocators, providing official interfaces for high-performance scenarios. Additionally, DropGuard enables cleanup closures on any exit path, and new standard library interfaces like conjure_zst are introduced. Cargo now highlights unused dependencies and strengthens supply chain security, while Clippy receives updates.

This release is significant for the Rust ecosystem: stabilizing the never type simplifies error handling and generic code, the Allocator API paves the way for embedded and high-performance computing, and supply chain security enhancements address growing software security concerns. Although some sources view this as a routine update, the stabilization of core features will likely attract more systems-level projects to adopt Rust.