libhoare

There's actually already a library that does what the author is talking about: https://github.com/nrc/libhoare They call it "design by contract" rather than "deductive verification" though. Wish there wouldn't be so many terms for the same thing. edit: There's also an existing RFC for this: https://github.com/rust-lang/rfcs/issues/1077

Well, there's a great aside in this thread as to whether or no DbC applies here in a discussion of formal verification and that's good stuff. But I figured it was relevant to mention that there are both an RFC [1] on adding DbC as a language feature and a library [2]. [1] https://github.com/rust-lang/rfcs/issues/1077 [2] https://github.com/nrc/libhoare

Bindings can leverage the ownership and borrowing principles in Rust to codify comments typically found in a C header about how its API should be used. Could the Rust compiler make use of design by contract style annotations in the C header? Maybe it could reason that an unsafe block is in some ways safe. There is a specification language for C called ACSL (which was designed for and is mainly used by Frama-C). Annotations look like: /*@ ensures \result >= 0; assigns \nothing; */ int foo(int x) { if (x < 0) return 0; return x; } I noticed there are annotations for Rust with the LibHoare library (https://github.com/nrc/libhoare). The example above might look like: #[postcond="result >= 0"] fn foo(x: int) -> int { if x < 0 { 0 } else {