For the latest documentation on Visual Studio 2017 RC, see Visual Studio 2017 RC Documentation.
warning C28304: For C++ reference-parameter <parameter_name>, an improperly placed
_Notref_ operator was found applied to <token>.
_Notref_ operator should only be used in special circumstances involving C++ reference parameters and only in system-provided macros. It must be immediately followed by a
_Deref_ operator or a functional annotation.