7 impl fmt::Display for Number {
8 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
9 write!(f, "{}", self.n)
14 list: Vec<Box<dyn ToString + 'static>> }
17 fn push(&mut self, n: Box<dyn ToString + 'static>) {
24 let n: Box<_> = Number { n: 42 }.into();
25 let mut l: Box<_> = List { list: Vec::new() }.into();
28 let x = n.to_string();
29 //~^ ERROR: borrow of moved value: `n`