But we went through that with C++ already: all companies used to publish their own guidelines of what C++ features were allowed and not allowed to use. Of cours

But we went through that with C++ already: all companies used to publish their own guidelines of what C++ features were allowed and not allowed to use. Of course, all these subsets were different. And of course, if you work on open source project, it's just impossible to be productive in such a language without knowing all of it.