"Avoid Premature Abstraction" darsida ko'rgan g'oyaning interfeysga oid ko'rinishi: har bir struct uchun "ehtiyot chorasi" sifatida interfeys yaratish — "interfeys ifloslanishi" deyiladi. Bu kerakmas murakkablik qo'shadi.

package main

import "fmt"

// Ifloslanish: faqat bitta implementatsiya bor, hech qachon almashtirilmaydi,
// lekin baribir interfeys orqali yashiringan
type UserStore interface {
	GetUser(id int) string
}

type dbUserStore struct{}

func (d dbUserStore) GetUser(id int) string { return fmt.Sprintf("user-%d", id) }

// Sodda: interfeyssiz, to'g'ridan-to'g'ri struct
type UserRepo struct{}

func (r UserRepo) GetUser(id int) string {
	return fmt.Sprintf("user-%d", id)
}

func main() {
	repo := UserRepo{}
	fmt.Println(repo.GetUser(7))
}

Agar dbUserStore — yagona implementatsiya bo'lsa va uni almashtirish rejasi yo'q bo'lsa (masalan testda soxtalashtirish ham kerak bo'lmasa), UserStore interfeysi hech qanday amaliy foyda bermaydi — u faqat qo'shimcha qatlam, "qaysi struct qaysi interfeysni amalga oshiradi" deb kuzatishni qiyinlashtiradi. Qoidani eslang: interfeys ikki yoki undan ko'p implementatsiya, testda almashtirish, yoki implementatsiyani yashirish kerak bo'lgandagina yarating ("When to Abstract" darsida ko'rgan).