无法打印数组切片

I'm playing around with Go language, using its online playground.

package main

import "fmt"

func main() {
    primes := [6]int{2, 3, 5, 7, 11, 13}

    var s []int = primes[1:6]
    fmt.Println(s)
}

This code prints nothing. Changing slice range to something else, for instance to [2:6] works as expected. I have tried it only using Go playground. Check it here.

Why it doesn't print anything? Probably it can be a Go compiler or Go playground bug, however I don't know the language so I'm not sure.

A few month later (June 2017), even the original example does work with the current iteration of the golang/playground.

That means the flushing issue after a fmt.Println as a last instruction of main() has been fixed.