switch_type.go

package main

import "fmt"

type myError struct {
	Message string
}

func (m *myError) Error() string {
	return "MyError: " + m.Message
}

func x() error {
	// return errors.New("Hello")
	// return &myError{Message: "huh"}
	return nil
}

func main() {
	err := x()
	switch e := err.(type) {
	case *myError:
		fmt.Println("here we go: ", e)

	default:
		fmt.Println("something else")
	}
}