Visual Studio C++ 2015 Update 3 introduced standard version switches [1]. They seem to only make sense for >= C++14 which I assume becomes relevant with the changes in !299 (#16468). Specifically for C++17 features `/std:c++latest` (and later `/std:c++17`) might be required. <br/> [1] https://blogs.msdn.microsoft.com/vcblog/2016/06/07/standards-version-switches-in-the-compiler/