typedef enum class Foobar : int {
    NONE = 0,
    FOO = 1,
    BAR = 2
} Foobar;

    typename std::enable_if<T == Foobar::FOO, std::underlying_type<Foobar>::type>::type base = static_cast<std::underlying_type<Foobar>::type>(Foobar::NONE);