[weberc2]

As jerf mentioned, there has been lots of talk; every single time the question of generics is raised here, /r/programming, or any Go-specific forum, it's addressed.

With respect to interfaces vs contracts; interfaces are about runtime polymorphism while contracts are about compile time polymorphism. This is an important difference when you consider []interface{Foo()} vs Slice(contract{Foo()})--an instance of the former can contain elements of varying concrete types while an instance of the latter can only contain elements of the same type. The other important detail is that interfaces only abstract over a single type while contracts support multiple type parameters (a single contract could specify a visitor type and a vistee type, for example).