What you're after here is called parametric polymorphism (commonly known as "generics"). Go does not have it. Debates still rage on the ML about whether to have

What you're after here is called parametric polymorphism (commonly known as "generics"). Go does not have it. Debates still rage on the ML about whether to have it or not, but nobody has yet come up with an implementation makes most happy. Go does have polymorphism though, in the form of subtype polymorphism. In Go, it is achieved using interfaces. Subtype polymorphism typically has more programmer overhead than parametric polymorphism, so it is not used for simpler things like a generic map, fold, etc. However, it can be used to reduce code duplication in other cases, like sorting (among many other things).