>The second type of productivity - which is getting more and more important - is across projects and codebases. And that gets thrown out of the window with generics.
Generics increase type safety (no more interface{} casts) and reduce code duplication. I don't see how this could possibly throw productivity "out the window". If anything, the effect will be the opposite. The tradeoff with generics has always been programmer time versus compile time and/or execution time. Assuming that programmers don't unnecessarily complicate things for themselves, programmer time will be significantly lessened with the introduction of generics. And there's nothing preventing programmers from burying themselves in a sea of abstraction even in a language without generics.
Generics increase type safety (no more interface{} casts) and reduce code duplication. I don't see how this could possibly throw productivity "out the window". If anything, the effect will be the opposite. The tradeoff with generics has always been programmer time versus compile time and/or execution time. Assuming that programmers don't unnecessarily complicate things for themselves, programmer time will be significantly lessened with the introduction of generics. And there's nothing preventing programmers from burying themselves in a sea of abstraction even in a language without generics.