Rust 寿命不'；只有当结构中有一个特征对象时，它才能生存

代码：

性状我的性状{
fn更新（&self，_prev:&self）{未实现！（）}
}
性状肌肉疗法性状{
//当v1被注释掉时，代码工作
v1:&'a dyn MyOtherTrait{}
结构容器；
impl容器{
//由PROC宏生成：无法更改
fn带_ref`
找到引用“%MyTraitDynWrapper”`
找到引用“&MyTraitDynWrapper
&”dyn TraitSo TLDR一旦我基本上拥有了
dyn traits，是的。说
dyn Trait
；底层类型可以很好地实现其他类型，就像它可以实现
Debug
，
Copy
，等等一样。但是你不能通过
dyn Trait>使用它们
error[E0308]: mismatched types
  --> src/lib.rs:33:23
   |
33 |             MyTrait::update(a, b)
   |                                ^ lifetime mismatch
   |
   = note: expected reference `&MyTraitDynWrapper<'_>`
              found reference `&MyTraitDynWrapper<'_>`
note: the anonymous lifetime #2 defined on the body at 32:14...
  --> src/lib.rs:32:14
   |
32 |           b.with_ref(|b| {
   |  ____________________^
33 | |             MyTrait::update(a, b)
34 | |         })
   | |_________^
note: ...does not necessarily outlive the anonymous lifetime #2 defined on the body at 31:13
  --> src/lib.rs:31:13
   |
31 |       a.with_ref(|a| {
   |  ________________^
32 | |         b.with_ref(|b| {
33 | |             MyTrait::update(a, b)
34 | |         })
35 | |     });
   | |_____^

error[E0308]: mismatched types
  --> src/lib.rs:33:23
   |
33 |             MyTrait::update(a, b)
   |                                ^ lifetime mismatch
   |
   = note: expected reference `&MyTraitDynWrapper<'_>`
              found reference `&MyTraitDynWrapper<'_>`
note: the anonymous lifetime #2 defined on the body at 31:13...
  --> src/lib.rs:31:13
   |
31 |       a.with_ref(|a| {
   |  ________________^
32 | |         b.with_ref(|b| {
33 | |             MyTrait::update(a, b)
34 | |         })
35 | |     });
   | |_____^
note: ...does not necessarily outlive the anonymous lifetime #2 defined on the body at 32:14
  --> src/lib.rs:32:14
   |
32 |           b.with_ref(|b| {
   |  ____________________^
33 | |             MyTrait::update(a, b)
34 | |         })
   | |_________^

error: aborting due to 2 previous errors

pub struct MyTraitDynWrapper<'a> {
    v1: &'a dyn for<'b> MyOtherTrait<'b>,
    v2: &'a (),
}

pub struct MyTraitDynWrapper<'a, 'b> {
    v1: &'a dyn MyOtherTrait<'b>,
    v2: &'a (),
}

// ...

impl Container {
    // GENERATED BY PROC MACRO: CANNOT CHANGE
    fn with_ref<'outer_borrow, 'that, ReturnType>(
        &'outer_borrow self,
        user: impl for<'this> FnOnce(&'outer_borrow MyTraitDynWrapper<'this, 'that>) -> ReturnType,
    ) -> ReturnType {
        unimplemented!()
    }
}