如果我已经为 U 实现了 From，Rust 是否会为 Vec 实现 From> ？

我有一个结构NotificationOption和另一个结构NotificationOption2以及一个实现From<NotificationOption> for NotificationOption2.

我想转换Vec<NotificationOption> to a Vec<NotificationOption2>:

struct NotificationOption {
    key: String,
}

struct NotificationOption2 {
    key: String,
}

impl From<NotificationOption> for NotificationOption2 {
    fn from(n: NotificationOption) -> Self {
        Self {
            key: n.key,
        }
    }
}

let options: Vec<NotificationOption> = ...;
let options2: Vec<NotificationOption2> = options.into();

但我收到编译器错误：

error[E0277]: the trait bound `Vec<NotificationOption2>: From<Vec<NotificationOption>>` is not satisfied
  --> src/main.rs:22:46
   |
22 |     let options2: Vec<NotificationOption2> = options.into();
   |                                              ^^^^^^^ ---- required by a bound introduced by this call
   |                                              |
   |                                              the trait `From<Vec<NotificationOption>>` is not implemented for `Vec<NotificationOption2>`

事实并非如此，但自己实现起来很简单：

let options2: Vec<NotificationOption2> = options.into_iter().map(|x| x.into()).collect();