With v15.5.2 I just noticed the compiler flag "/permissive-". If enabled just "#include <pybind11/pybind11.h>" will generate the error: ``` error C2884: 'pybind11::detail::_': introduced by using-declaration conflicts with local function 'pybind11::detail::_' ``` The solution is to set Conformance Mode to "No". For whatever reason this flag was enabled when I created a new project.