> In formal terms, Rust’s type system is considered affine, which means that each value must be used at most once. And “use at most once” is exactly what’s need

> In formal terms, Rust’s type system is considered affine, which means that each value must be used at most once. And “use at most once” is exactly what’s needed to guarantee the absence of bugs like “use after free”. > But there are type systems which can provide even more guarantees. One step beyond “use at most once” is “use exactly once”. Types that provide that guarantee are called “linear” and in addition to guaranteeing the absence of “use after free” they can also guarantee the absence of memory leaks. Does anyone know why these are called “affine” and “linear”, respectively? What’s the analogy, if any, to the use of those terms in math? (E.g. an affine transformation of vector spaces)