我有一个包含两个字段的 struct ，我想用另一个字段(不可变borrow )修改一个字段(可变borrow )，但borrow 判断器出错.
例如，以下代码:
struct Struct {
field1: Vec<i32>,
field2: Vec<i32>,
}
fn main() {
let mut strct = Struct {
field1: vec![1, 2, 3],
field2: vec![2, 3, 4],
};
strct.field1.retain(|v| !strct.field2.contains(v));
println!("{:?}", strct.field1);
}
给出以下错误:
error[E0502]: cannot borrow `strct.field1` as mutable because it is also borrowed as immutable
--> src/main.rs:12:5
|
12 | strct.field1.retain(|v| !strct.field2.contains(v));
| ^^^^^^^^^^^^^------^---^^-----^^^^^^^^^^^^^^^^^^^^
| | | | |
| | | | first borrow occurs due to use of `strct` in closure
| | | immutable borrow occurs here
| | immutable borrow later used by call
| mutable borrow occurs here
在一个闭包中使用另一个字段更新一个字段的方法是什么？