Go needs functions that support parametric types for collections. I'm not even talking about generics here as user defined types. Let's forget about generics or

Go needs functions that support parametric types for collections. I'm not even talking about generics here as user defined types. Let's forget about generics or "the ability for developers to implement their own type safe containers". Let's talk about the fact that functions in Go could support type parameters in signatures , something like : func Map<V,W>(slice []V,func(element V)W)[]W { // ... } What we have here is a guarantee that at compile time, this code is safe. We didn't introduce generics, slice is a Go slice of V and the result is a go slice of W. The code should then be used this way : result := Map<string,string>([]string{"a","b"}, func(e string)string{ return e+"foo" } ) This is completely type safe, no reflection is used, the compiler knows all the types at compile time and no generic type was introduced. This is a good trade off and merely syntactic sugar that would enable developers to get rid of interface {} parameter + type assertions.