Why not remove trait FnBox ?

[zydxhs]

FnOnce already replaces FnBox, so why implement it yourself?

1. 删除以下代码：

trait FnBox {
    fn call_box(self: Box<Self>);
}

impl<F: FnOnce()> FnBox for F {
    fn call_box(self: Box<F>) {
        (*self)()
    }
}

2. 修改代码

type Thunk<'a> = Box<FnBox + Send + 'a>;

改成

type Thunk<'a> = Box<dyn FnOnce() -> () + Send + 'a>;

job.call_box();

改成

job();

[dns2utf8]

Hi @zydxhs

This was implemented to be compatible with rust 1.9.x back in the day.
With the threadpool 2.0 this might change, however dereferencing the supplied closure required because it enables a VTable.

Does this answer you question?

Cheers
Stefan