#![allow(unused_variables)]
#![feature(try_with_capacity)]
fn main() {
    #[allow(unused)]
    fn example() -> Result<(), std::collections::TryReserveError> {
        use std::collections::VecDeque;
        let deque: VecDeque<u32> = VecDeque::try_with_capacity(10)?;
        Ok(())
    }
}