Rust 1.100 Stabilizes the Never Type: Match Exhaustiveness, Generic Returns, and FFI Signatures
Rust 1.100 reportedly stabilizes the never type after a decade of design work, giving diverging expressions a first-class bottom type. This short walks through what actually changes for your builds and what a one-line headline can't tell you. What the video covers: - Return-position `!` has been stable since 1.0; type-position `!` still fails on stable with error E0658. - Why the gate is positional, not semantic, and what that means for signatures like a return type carrying never. - The distinction that matters: return-position `!` lets you describe divergence, type-position `!` lets you reason about it, because inference has to pick a type. - The three open questions: which fallback policy ships, whether a blanket conversion impl comes with it, and whether the change is edition gated. The post treats the stabilization claim as reported rather than verified, and gives a reproducible probe for each behavior so you can confirm it on the toolchain in front of you. Full write-up: https://hackyjs.com/posts/rust-1100-stabilizes-the-never-type-match-exhaustiveness-generic-returns-and-ffi-signatures