Rust by example - http://rustbyexample.com/bounds.html issues

bounds.rs

use std::ops::{Add, Sub, Mul};

#[derive(Show, Copy)]
struct Vec2<T> {
    x: T,
    y: T,
}

// Apply bound to `T` at first instance of `T`. `T`
// must implement the `Add` trait.
impl<T: Add<T>> Add<Vec2<T>>
        for Vec2<T> {
    type Output = Vec2<T>;

    fn add(self, rhs: Vec2<T>) -> Vec2<T> {
        Vec2 {
            // `x` and `y` are of type `T`, and implement the `add` method
            x: self.x.add(rhs.x),
            // The sugary `+` operator can also be used
            y: self.y + rhs.y,
        }
    }
}

// Bound: `T` must implement the `Sub` trait
impl<T> Sub<Vec2<T>> for Vec2<T>
        where T: Sub<T> {
    type Output = Vec2<T>;

    fn sub(self, rhs: Vec2<T>) -> Vec2<T> {
        Vec2 {
            x: self.x - rhs.x,
            y: self.y - rhs.y,
        }
    }
}

// Bound: `T` must implement *both* the `Add` trait and the `Mul` trait
impl<T> Vec2<T>
        where T: Add<T> + Mul<T> {
    fn dot(self, rhs: Vec2<T>) -> T {
        (self.x * rhs.x) + (self.y * rhs.y)
    }
}

fn main() {
    // Floats implement the `Add`, `Mul` and `Sub` traits
    let v1 = Vec2 { x: 1.2_f32, y: 3.4 };
    let v2 = Vec2 { x: 5.6_f32, y: 7.8 };

    println!("{} + {} = {}", v1, v2, v1 + v2);
    println!("{} - {} = {}", v1, v2, v1 - v2);
    println!("{} â‹… {} = {}", v1, v2, v1.dot(v2));

    // Error! `char` doesn't implement the `Add` trait
    //println!("{}", Vec2 { x: ' ', y: 'b' } + Vec2 { x: 'c', y: 'd' });
    // FIXME ^ Comment out this line
}

error.log

bounds.rs:16:9: 21:10 error: mismatched types: expected `Vec2<T>`, found `Vec2<<T as core::ops::Add>::Output>` (expected type parameter, found associated type)
bounds.rs:16         Vec2 {
bounds.rs:17             // `x` and `y` are of type `T`, and implement the `add` method
bounds.rs:18             x: self.x.add(rhs.x),
bounds.rs:19             // The sugary `+` operator can also be used
bounds.rs:20             y: self.y + rhs.y,
bounds.rs:21         }
bounds.rs:31:9: 34:10 error: mismatched types: expected `Vec2<T>`, found `Vec2<<T as core::ops::Sub>::Output>` (expected type parameter, found associated type)
bounds.rs:31         Vec2 {
bounds.rs:32             x: self.x - rhs.x,
bounds.rs:33             y: self.y - rhs.y,
bounds.rs:34         }
bounds.rs:42:9: 43:6 error: binary operation `+` cannot be applied to type `<T as core::ops::Mul>::Output`
bounds.rs:42         (self.x * rhs.x) + (self.y * rhs.y)
bounds.rs:43     }
error: aborting due to 3 previous errors