> One use of "unsafe" that was not mentioned by Nora but is important for the embedded community in particular is the use of "unsafe" to flag things which from the point of view of Rust itself are fine, but are dangerous enough to be worth having a human programmer directed away from them unless they know what they're doing.

Rust gave up this notion when they decided that mem::forget could, in fact, be safe, since even though it was initially marked unsafe it could be trivially implemented in safe code using only safe constructs from the stdlib.

We need another keyword or concept to refer to unsafeness that isn't related to UB. Some people suggested tagging unsafe with something like

    // declare SummonsDemons as some kind of safety market that goes beyond preventing UB

    unsafe(SummonsDemons) fn f() {
        // summons demons
    }

    fn safecode() {
        // SAFETY: the demons are cool this time
        unsafe(SummonsDemons) { f() }
    }