MiniRust is the cornerstone of the project author’s vision for a Rust semantics specification. It is an idealized MIR-like language intended to be Rust’s “Core Language”.

The goal of MiniRust is to specify precisely the operational behavior of Rust, that is, the behavior that a Rust program may exhibit when executed: the behavior of a Rust program is defined by first translating it into MiniRust, and then according to the possible behavior of a MiniRust program specified in this document. This translation does a lot of work; for example, at the MiniRust level, traits and pattern matching are basically gone. MiniRust, on the other hand, pays attention to a lot of details, such as precise evaluation order and data representation, and precise undefined behavior.