Beware accidentally using non-pointer values when calling register gob

Register Gob Caution

package main

import (
	"bytes"
	"encoding/gob"
	"fmt"
)

type Animal interface {
	Height() int
}

type Man struct {
	H int
}

func (m *Man) Height() int {
	return m.H
}

type SendMe struct {
	Animal Animal
}

func main() {
	var m Man
	m.H = 99

	var s SendMe
	s.Animal = &m

	// do not do this
	// gob.Register(Man{})
	// do not do this

	gob.Register(&Man{})

	var network bytes.Buffer
	enc := gob.NewEncoder(&network)
	dec := gob.NewDecoder(&network)

	err := enc.Encode(&s)
	if err != nil {
		panic(err)
	}

	var s2 SendMe
	err = dec.Decode(&s2)
	if err != nil {
		panic(err)
	}
	fmt.Printf("%+v %+v %+v\n", m, s2, s2.Animal)
}