"由于要求冲突，无法推断函数调用中生命周期参数 '_ 的适当生命周期"

Question

i have a vector of a struct

 let list = vec![
        ListenerList {
            listener: Pattern {
                cmd: "sum"
            },
            handler: |listener, connection| Box::pin(simple_handler(listener, connection))
        }
    ];

Answer 1

The problem is in the definition of the handler<\/code> field of ListenerList<\/code> , which has this type:

fn(Subscription, &Connection) -> Pin<Box<dyn futures::Future<Output = ()>>>