Rust 1.100 lands with never type and Allocator API
Original: Rust 1.100
Why This Matters
Custom allocators and a stable never type unblock performance-critical and systems-level Rust codebases.
The Rust team released version 1.100.0 on Nov. 12, 2026, stabilizing the long-awaited never type (!) after 10 years and 5 failed attempts, plus the core Allocator API enabling custom memory allocators for Vec and Box.
Rust 1.100.0 arrives with several headline stabilizations. Most notable is the never type (!), which represents computations that never return a value — think return, break, and process::exit. After a decade and five failed attempts, it's finally stable. The release also makes Infallible an alias for !, unifying old APIs with the new type. There's a catch: a breaking change to the "never type fallback" now applies to editions 2015, 2018, and 2021, shifting it from () to !, mirroring what edition 2024 already did. The Rust team says impact should be minimal, with future-compatibility warnings issued in advance and patches already published for affected crates.
The Allocator API also lands in stable, letting library authors plug in custom allocators with Vec and Box via the new Allocator trait. This marks the foundation of the Allocators 1.0 project goal, though significant work remains. Additional stabilizations include DropGuard, APIs for conjuring zero-sized types, Cargo reporting on unused dependencies, reduced Cargo cache collisions, and a new min-publish-age setting for Cargo.