The article discusses 'only bounds', a significant upcoming change to Rust's type system being developed by the Arm team. It explains how Rust currently handles Sized bounds by default on generic type parameters and the implications for dynamically sized types, while introducing the new 'only bounds' feature that will modify this behavior.
Background
Rust currently applies a default Sized bound to all generic type parameters, requiring explicit opt-out for dynamically sized types. This design dates back to 2014 and affects how developers work with unsized types in the language.
- Source
- Lobsters
- Published
- Jun 9, 2026 at 09:01 PM
- Score
- 7.0 / 10