rust - 在 Vec 中嵌套生命周期时，生命周期参数的数量错误

Question

我正在尝试构建一个包含对另一个结构的向量的引用的结构，如下所示:

pub struct Downstream<'a> {
    frequency: i32,
    slot: i32,
    connector: i32,
    description: String,
    cablemac: &'a CableMac,
}

pub struct Upstream<'a> {
    downstreams: Vec<Downstream>,
}

无论我尝试什么，我总是会遇到这个生命周期错误:

src/e6000/mod.rs:13:22: 13:32 error: wrong number of lifetime parameters: expected 1, found 0 [E0107]
src/e6000/mod.rs:13     downstreams: Vec<Downstream>,

E0107 一点用都没有。

我在哪里以及如何放置一个 'a 来让它工作？

Answer 1

downstreams: Vec<Downstream>,

应该是

downstreams: Vec<Downstream<'a>>,

---

E0107 doesn't help at all.

您应该运行 rustc --explain E0107。

该命令的输出当前以一些很好的示例开头:

This error means that an incorrect number of lifetime parameters were provided for a type (like a struct or enum) or trait.

Some basic examples include:

struct Foo<'a>(&'a str);
enum Bar { A, B, C }

struct Baz<'a> {
    foo: Foo,     // error: expected 1, found 0
    bar: Bar<'a>, // error: expected 0, found 1
}