Line 19 Compiles with Go 1.3.3

go.go

package main

import "fmt"

type poolJSON struct {
	Clusters []clusterJSON `json:"clusters"`
}

type clusterJSON struct {
	InstanceID string        `json:"instance_id"`
}


func main() {
	poolJ := poolJSON{}
	poolJ2 := poolJSON{}
	clusterJ := clusterJSON{InstanceID: "foobar"}

	poolJ.Clusters = append(poolJ, clusterJ)
	poolJ2.Clusters = append(poolJ2.Clusters, clusterJ)

	fmt.Printf("%T\t%+v\n", poolJ.Clusters, poolJ.Clusters)
	fmt.Printf("%T\t%+v\n", poolJ2.Clusters, poolJ2.Clusters)
}