Rust 有什么办法可以追踪泛型的单态化过程吗

我发现，当泛型关系错综复杂时，仅通过阅读简单的源代码是无法追踪的.

有没有办法透露编译器对特定泛型 struct 或函数的实例化轨迹？

Elaborated:

感谢你对这个问题感兴趣.它在这里进行了详细阐述.我最近在研究经度 crate .因此，以它为例.

use warp::Filter;

async fn handler_without_parameter() -> Result<impl warp::Reply, warp::Rejection> {
    Ok(warp::reply::json(&"dumb".to_string()))
}

fn main() {
    let get_items = warp::get()
        .and(warp::path("/"))
        .and(warp::path::end())
        .and_then(handler_without_parameter); //Ok here
}

async fn handler_without_parameter() -> Result<impl warp::Reply, warp::Rejection> {
    Ok(warp::reply::json(&"dumb".to_string()))
}

fn main() {
    let para: HashMap<String, String> = HashMap::new();
    let para_filter = warp::any().map(move || para.clone()); // A filter with data

    let get_items = warp::get()
        .and(warp::path("/"))
        .and(warp::path::end())
        .and(para_filter)      //chain with the data filter
        .and_then(handler_without_parameter); // error[E0593]: function is expected to take 1 argument, but it takes 0 arguments
}

在链接筛选器(它与数据一起)之后，方法and_then的参数预期为1个自变量.我对and_then的这个需求变化很好奇，所以我试着弄清楚这个方法的单形化过程.

https://docs.rs/warp/0.3.5/warp/trait.Filter.html#method.and_then个

    fn and<F>(self, other: F) -> And<Self, F>
    where
        Self: Sized,
        <Self::Extract as Tuple>::HList: Combine<<F::Extract as Tuple>::HList>,
        F: Filter + Clone,
        F::Error: CombineRejection<Self::Error>,
    {
        And {
            first: self,
            second: other,
        }
    }


    fn and_then<F>(self, fun: F) -> AndThen<Self, F>
    where
        Self: Sized,
        F: Func<Self::Extract> + Clone,
        F::Output: TryFuture + Send,
        <F::Output as TryFuture>::Error: CombineRejection<Self::Error>,
    {
        AndThen {
            filter: self,
            callback: fun,
        }
    }

基本特征是:

pub trait FilterBase {
    type Extract: Tuple; // + Send;
    type Error: IsReject;
    type Future: Future<Output = Result<Self::Extract, Self::Error>> + Send;

    fn filter(&self, internal: Internal) -> Self::Future;

    fn map_err<F, E>(self, _internal: Internal, fun: F) -> MapErr<Self, F>
    ...
}

我不明白为什么添加的链接会引起and_then方法的需求更改，因为对我来说，这里的泛型关系非常复杂.

Even with the hints provided by rust-analyzer, it doesn't help a lot, because the Extract = ... part is eclipsed.