Unable to compile this code where my structure uses operator>> overload

Question

I have this structure:

struct S_SPECIAL_EVENT
{
    BOOL            bEventAllDay{};

    friend CArchive& operator<<(CArchive& rArchive, S_SPECIAL_EVENT const& rsSE)
    {
        const WORD wVersion = 1;
        return rArchive << wVersion
            << gsl::narrow<bool>(rsSE.bEventAllDay);
    }

    friend CArchive& operator>>(CArchive& rArchive, S_SPECIAL_EVENT &rsSE)
    {
        WORD wVersion{};

        rArchive >> wVersion;
        rsSE.bEventAllDay = readAndCast<BOOL, bool>(rArchive);

        return rArchive;
    }
};

I tried adding the two serialize operators. But I get compile errors like:

error C3861: 'readAndCast': identifier not found

The method in question is defined in the application header:

// See: https://stackoverflow.com/a/58746336/2287576
template <typename T, typename U>
T readAndCast(CArchive& ar) {
    U x;
    ar >> x;
    return static_cast<T> (x);
}

I have included that header in my file. So why won't it complile?

---

I changed my code to do things manually:

friend CArchive& operator>>(CArchive& rArchive, S_SPECIAL_EVENT &rsSE)
{
    WORD wVersion{};
    bool bData{};

    rArchive >> wVersion;
    rArchive >> bData;
    rsSE.bEventAllDay = gsl::narrow<BOOL>(bData);

    return rArchive;
}

But I would like to know the answer to the original question.