/// Uses `unreachable!()` in debug mode but `std::hint::unreachable_unchecked()`
/// in release mode.
unsafe fn unreachable_debug() {
    #[cfg(debug_assertions)]
    unreachable!();
    #[cfg(not(debug_assertions))]
    std::hint::unreachable_unchecked();
}

fn main() {
    match 1 {
        1 => {},
        _ => unsafe { unreachable_debug() },
    }
}