typed nil #2

package main

import (
    "fmt"
)

type UnknownError struct {
    message string
}

func (err *UnknownError) Error() string {
    return err.message
}

func main() {
    var uerr *UnknownError
    var err error

    fmt.Println(err == nil)
    fmt.Println(uerr == nil)

    err = uerr

    fmt.Println(err == nil)
}