在Go语言中，为什么“ << 0”运算将得到1？

I am quite confused about the go left shift operator. I run the following code:

package main

func main(){
    var x = 1 << 0
    println(x)
}

And I get 1. But I think the result should be zero.

1 << 0 means:

Take 1 and don't shift it. The result should be the original number: 1