Just got proposed experimental::expected<T, E> working on Visual Studio 14 CTP 3. This is a fairly heavy generalised constexpr C++14 library proposed for C++17, and it happily segfaulted Microsoft's compiler and blew it up in all sorts of fun ways. With a bit of working around and disabling constexpr completely, it compiles and passes all unit tests. Took two days of head scratching though. Anyway this opens my next step which is to implement non allocating future promise, and really I had to be able to say it could work on Microsoft's compiler next year before I invested the effort. Looking good.