我正在研究Rust by Example个例子.
#[derive(Debug)]
struct Point {
x: f64,
y: f64,
}
#[derive(Debug)]
struct Rectangle {
p1: Point,
p2: Point,
}
fn main() {
let mut point: Point = Point { x: 0.3, y: 0.4 };
println!("point coordinates: ({}, {})", point.x, point.y);
let rectangle = Rectangle {
p1: Point { x: 1.0, y: 1.0 },
p2: point,
};
point.x = 0.5; // Why does the compiler not break here,
println!(" x is {}", point.x); // but it breaks here?
println!("rectangle is {:?} ", rectangle);
}
我得到这个错误(Rust 1.25.0):
error[E0382]: use of moved value: `point.x`
--> src/main.rs:23:26
|
19 | p2: point,
| ----- value moved here
...
23 | println!(" x is {}", point.x);
| ^^^^^^^ value used here after move
|
= note: move occurs because `point` has type `Point`, which does not implement the `Copy` trait
我知道我给Rectangle
对象加了point
,这就是为什么我不能再访问它,但为什么编译在println!
上失败,而不是前一行的赋值?