rust语言match模式匹配涉及转移所有权Error Case

灵山悟空2025-03-11 22:44

rust 复制代码

struct S{
    data:String,
}

//注意：因为String默认是移动语义，从而决定结构体S也是移动语义，可采用(1)或(2)两种方法解决编译错误；关键思路：放弃获取结构体S的字段data的所有权，改为借用。

fn process(s_ref:&S){//&S ，借用
    
    match *s_ref { //S ， 值
    //(1) match s_ref { //&S ， 借用

        //(2) S{ref data} => { //data:&String ， 借用
        S{data} => { //出错点.
            
            println!("Data: {}",data);
        },
       // _ => {},
    }
}

fn main(){
    let s = S{
        data:String::from("hello world"),
    };
    
    process(&s);
}

编译错误：

rust 复制代码

   Compiling playground v0.0.1 (/playground)
error[E0507]: cannot move out of `s_ref.data` which is behind a shared reference
  --> src/main.rs:7:11
   |
7  |     match *s_ref { 
   |           ^^^^^^
...
11 |         S{data} => {
   |           ----
   |           |
   |           data moved here
   |           move occurs because `data` has type `String`, which does not implement the `Copy` trait
   |
help: consider removing the dereference here
   |
7  -     match *s_ref { 
7  +     match s_ref { 
   |

For more information about this error, try `rustc --explain E0507`.
error: could not compile `playground` (bin "playground") due to 1 previous error

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