如何使用通过Golang中的引用传递的索引从切片访问元素

I passed a reference of a slice to a function and I am making changes in the slice inside the function. Also I am trying to access an element from the slice using index. It is throwing exception in golang. What is the best way to access an element from a slice by index which is passed by reference? You can find a sample code here. [ref : http://www.reddit.com/r/golang/comments/283vpk/help_with_slices_and_passbyreference/ ]. Since my code is huge I added a sample.

package main

import "fmt"

type mystruct struct {
    val int
}

func main() {
    var s1 []mystruct
    var s2 []mystruct

    onlyPassing(&s1)
    s2 = returningToo(s2)

    fmt.Printf("%#v
%#v", s1, s2)
}

func onlyPassing(s *[]mystruct) {
    *s = append(*s, mystruct{1})
    m := *s[0]

}

func returningToo(s []mystruct) []mystruct {
    s = append(s, mystruct{1})
    return s
}

And you can find the implementation here. Could anyone help me on this.