I don't see a lot of cost associated with the duck typing-ish approach go takes with interfaces. Instead of passing an implementation directly (or even having i

I don't see a lot of cost associated with the duck typing-ish approach go takes with interfaces. Instead of passing an implementation directly (or even having it in the first place) you can develop with an interface from the get go. Makes for easier tests too. In my experience the cost is lower if you write code the way you described (and you don't need to plan ahead as much)