Macro mirai_annotations::verify_unreachable

macro_rules! verify_unreachable {
    () => { ... };
    ($message : literal) => { ... };
    ($msg : expr,) => { ... };
    ($fmt : expr, $($arg : tt) *) => { ... };
}

Equivalent to unreachable! when used with an unmodified Rust compiler. When compiled with MIRAI, this causes MIRAI to verify that the annotation statement cannot be reached.