Naive circular queue in Rust

main.rs

use std::fmt;

#[derive(Debug)]
struct CircularQueue<T> {
    max: usize,
    list: Vec<T>,
}

impl <T> CircularQueue<T> where T: std::string::ToString {
    pub fn new(max: usize) -> CircularQueue<T> {
        CircularQueue {
            max: max,
            list: Vec::new(),
        }
    }

    pub fn enq(&mut self, number: T) {
        self.list.push(number)
    }

    // Not really a `shift` here. The way remove works, is
    // by removing the element and then shifting everything left.
    pub fn deq(&mut self) -> T {
        self.list.remove(0)
    }
}

impl <T> fmt::Display for CircularQueue<T> where T: std::string::ToString {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        write!(f, "[{}]",
           self.list.iter().fold(String::new(), |acc, num| acc + &num.to_string() + ", ")
        )
    }
}

fn main() {
    let mut cq = CircularQueue::new(7);
    cq.enq(1);
    cq.enq(2);
    println!("{}", cq);
    cq.deq();
    println!("{}", cq);
}