在`std :: thread :: joinhandle`中都找不到方法或关联的常数`join``

Question

pub type RunnableJoinHandle = Box<dyn RunnableJoinHandleTrait>;
pub trait RunnableJoinHandleTrait {
    fn join(self) -> Result<(), ()>;
}
impl RunnableJoinHandleTrait for std::thread::JoinHandle<()> {
    fn join(self) -> Result<(), ()> {
        <Self as std::thread::JoinHandle<()>>::join(self)
    }
}

错误：

error[E0576]: cannot find method or associated constant `join` in `std::thread::JoinHandle`
 --> src/lib.rs:7:48
  |
7 |         <Self as std::thread::JoinHandle<()>>::join(self)
  |                                                ^^^^ not found in `std::thread::JoinHandle`

但是很明显，该方法存在

https://play.rust-lang.org/?version=stable&mode=debug&edition=2021&gist=fdf0883c23805adcae4b3ca4337e386c

Answer 1

JoinHandle 不是一个特征，因此不适用完整的合格特征语法。直接调用该方法，而没有完全限定的特质语法：

std::thread::JoinHandle::join(self).unwrap()

错误消息当然不好。