What steps will reproduce the problem?
1. capture the code in this description to xml_parse.go
2. go run xml_parse.go

What is the expected output?
a::b::c::nil

What do you see instead?
 :: nil

Which compiler are you using (5g, 6g, 8g, gccgo)?
go

Which operating system are you using?
archlinux x86_64

Which revision are you using?  (hg identify)
58bc8aae4abb

Please provide any additional information below.

// sample from http://research.swtch.com/godata2
package main

import (
    "encoding/xml"
    "fmt"
    "log"
)

var encoded = `
   <list><value>a</value>
       <list><value>b</value>
           <list><value>c</value>
           </list>
       </list>
   </list>
`

type List struct {
    Value string
    List  *List
}

func (l *List) String() string {
    if l == nil {
        return "nil"
    }
    return l.Value + " :: " + l.List.String()
}

func main() {
    var l *List
    err := xml.Unmarshal([]byte(encoded),&l)
    if err != nil {
        log.Fatalln("xml.Unmarshal: ", err)
    }
    fmt.Println(l)
}