struct A { /* ... */ }
struct B { /* ... */ }
struct C {
    a: A,
    b: B,
}

impl A {
    fn close(self) -> Result<(), A> { /* ... */ }
}
impl B {
    fn close(self) -> Result<(), B> { /* ... */ }
}

impl C {
    fn close(self) -> Result<(), C> {
        let C { a, b } = self;
        match a.close() {
            Ok(()) => {}
            Err(a) => return Err(C { a, b }),
        }
        match b.close() {
            Ok(()) => Ok(())
            Err(b) => {
                // panic? store an `Option<A>`? different error?
            }
        }
    }
}