Dilemma: a type can only implement driver.Valuer for value or pointer (not both)

valuer.go

package main

import (
	"database/sql"
	"database/sql/driver"
	_ "github.com/lib/pq"
	"log"
)

func E(err error) {
	if err != nil {
		log.Fatal(err)
	}
}

type MyType struct {
	S string
}

// Only non-pointer implemented: panic on nil values
// panic: value method main.MyType.Value called using nil *MyType pointer
func (m MyType) Value() (v driver.Value, err error) {
	v = m.S
	return
}

// Only pointer implemented: error
// error: sql: converting Exec argument #0's type: unsupported type main.MyType, a struct
/*
func (m *MyType) Value() (v driver.Value, err error) {
	if m != nil {
		v = m.S
	}
	return
}
*/

func main() {
	db, err := sql.Open("postgres", "dbname=homeboy_dev sslmode=disable")
	E(err)
	exec := func(q string, args ...interface{}) {
		_, err = db.Exec(q, args...)
		E(err)
	}
	exec(`drop table if exists t`)
	exec(`create table t(i text, j text)`)
	i := MyType{"spam"}
	var j *MyType // &MyType{"eggs"} // panic if nil
	exec(`insert into t(i, j) values($1,$2)`, i, j)
}