Ref<(A, Option<B>)> -> Ref<Option<(A, B)>>?

    pub fn foo<A, B>(x: Ref<(A, Option<B>)>) -> Ref<Option<(A, B)>> {
        Ref::map(x, |(a, ob)| match ob {
            None => None,
            Some(b) => Some((a, b)),

I understand that the above code does not work. My question is: is there a way to make it work? The problem I seem to run into is that any & we generate is unlikely to live long enough.

This, once again, is using std::cell::Ref - Rust

no, it should be impossible

A potentially useful alternative that is possible is e.g.
Ref<(A, Option<B>) -> Option<(Ref<A>, Ref<B>)> (using Ref::map_split).