Oxide: The Essence of Rust
share
Rust is a major advancement in industrial programming languages due in large part to its success in bridging the gap between low-level systems programming and high-level application programming. This success has ultimately empowered programmers to more easily build reliable and efficient software, and at its heart lies a novel approach to ownership that balances type system expressivity with usability. In this work, we set out to capture the essence of this model of ownership by developing a type systems account of Rust's borrow checker. To that end, we present Oxide, a formalized programming language close to source-level Rust (but with fully-annotated types). This presentation takes a new view of lifetimes as approximate provenances of references, and our type system is able to automatically compute this information through a flow-sensitive substructural typing judgment for which we prove syntactic type safety using progress and preservation. The result is a simpler formulation of borrow checking - including recent features such as non-lexical lifetimes - that we hope researchers will be able to use as the basis for work on Rust.
READ FULL TEXT