interface - Go 界面中的设计决策{}

Question

为什么 Go 不会自动转换:

package main

import "fmt"

type Any interface{} // Any is an empty interface
type X func(x Any) // X is a function that receives Any

func Y(x X) { // Y is a function that receives X
  x(1)
}

func test(v interface{}) { // test is not considered equal to X
  fmt.Println("called",v)
}

func main() {
  Y(test) // error: cannot use test (type func(interface {})) as type X in argument to Y
}

还有这个:

package main
import "fmt"

type Any interface{}

func X2(a Any) {
  X(a)
} 
func Y2(a interface{}) {
  X2(a) // this is OK
}

func X(a ...Any) {
  fmt.Println(a)
}
func Y(a ...interface{}) { // but this one not ok
  X(a...) // error: cannot use a (type []interface {}) as type []Any in argument to X
}

func main() {
  v := []int{1,2,3}
  X(v)
  Y(v)
}

我真的希望 interface{} 可以在任何东西(slices、map)上重命名为 Any , func) 不仅仅是简单的类型

第二个问题是:有没有办法让它成为可能？

Answer 1

第一个是关于type conversion和 type identity ，你有一套规则。
在“Why can I type alias functions and use them without casting?”中查看更多信息

• type Any interface{} 是命名类型
• interface{} 是一个未命名的类型

它们的身份不同，不能用func(interface[})代替func(Any)。

---

第二个由 golang faq 涵盖

我可以将 []T 转换为 []interface{} 吗？

Not directly, because they do not have the same representation in memory.
It is necessary to copy the elements individually to the destination slice. This example converts a slice of int to a slice of interface{}:

t := []int{1, 2, 3, 4}
s := make([]interface{}, len(t))
for i, v := range t {
    s[i] = v
}

有关内存表示的更多信息，请参见“what is the meaning of interface{} in golang?”: