相关疑难解决方法(0)

编译器允许我编写如下函数的全面实现：

trait Invoke {
    type S;
    type E;

    fn fun(&mut self) -> Result<Self::S, Self::E>;
}

impl<F, S, E> Invoke for F
where
    F: Fn() -> Result<S, E>,
{
    type S = S;
    type E = E;

    fn fun(&mut self) -> Result<S, E> {
        self()
    }
}

但是当我尝试添加函数参数时它开始抱怨：

trait Invoke {
    type A;
    type S;
    type E;

    fn fun(&mut self, arg: Self::A) -> Result<Self::S, Self::E>;
}

impl<F, A, S, E> Invoke for F
where
    F: Fn(A) -> Result<S, E>,
{
    type …

我有一个通用类型的特征.我想定义一个具有满足该特征的属性的结构,我想在该结构中实现一个使用特征内部函数的函数:

pub trait Point<I> {
    fn id(&self) -> I;
}

pub struct Connection<T> {
    pub to: T,
}

impl<T: Point> Connection<T> {
    pub fn is_connected_to(&self, point: T) -> bool {
        self.to.id() == point.id()
    }
}

pub fn main() {
    struct SimplePoint;
    impl Point<char> for SimplePoint {
        fn id(&self) -> char {
            return 'A';
        }
    }

    let a = SimplePoint {};

    let conn = Connection { to: a };
}

(游乐场)

如果我尝试运行此代码,则会收到错误消息:

error[E0243]: wrong number of type arguments: expected …