Dive into and validate map keys?

[ehsandavari]

Package version eg. v9, v10:

v10

Issue, Question or Enhancement:

Question

Code sample, to showcase or reproduce:

package main

import (
	"fmt"
	"github.com/go-playground/validator/v10"
)

type TI18nKey string

const (
	I18nKeyInternalServer               TI18nKey = "InternalServer"
	I18nKeyBadRequest                   TI18nKey = "BadRequest"
	I18nKeyNotFound                     TI18nKey = "NotFound"
	I18nKeyUserPhoneNumberExists        TI18nKey = "UserPhoneNumberExists"
	I18nKeyPhoneNumberOrPasswordInvalid TI18nKey = "PhoneNumberOrPasswordInvalid"
)

func (r TI18nKey) String() string {
	return string(r)
}

func (r TI18nKey) IsValid() bool {
	switch r {
	case I18nKeyInternalServer,
		I18nKeyBadRequest,
		I18nKeyNotFound,
		I18nKeyUserPhoneNumberExists,
		I18nKeyPhoneNumberOrPasswordInvalid:
		return true
	default:
		return false
	}
}

type TLanguage string

const (
	LanguageEN TLanguage = "en"
	LanguageFA TLanguage = "fa"
)

func (r TLanguage) String() string {
	return string(r)
}

func (r TLanguage) IsValid() bool {
	switch r {
	case LanguageEN,
		LanguageFA:
		return true
	default:
		return false
	}
}

type Config struct {
	Messages map[TLanguage]map[TI18nKey]string `validate:"required,dive,keys,customType"`
}

func main() {
	validate := validator.New()
	validate.RegisterValidation("customType", customTypeValidator)

	messages := map[TLanguage]map[TI18nKey]string{
		LanguageEN: {
			I18nKeyInternalServer: "en internal server error",
			"NotRegisteredKey":    "in this case expect validator return validation error",
		},
		LanguageFA: {
			I18nKeyInternalServer: "fa internal server error",
			"NotRegisteredKey":    "in this case expect validator return validation error",
		},
		"NotRegisteredLanguage": {}, // in this case validator is return error : its true
	}

	err := validate.Struct(Config{Messages: messages})
	if err != nil {
		fmt.Printf("messages not valid! %s\n", err)
	}
}

type iCustomTypeValidatorValidator interface {
	IsValid() bool
}

func customTypeValidator(fl validator.FieldLevel) bool {
	value := fl.Field().Interface().(iCustomTypeValidatorValidator)
	return value.IsValid()
}