As a user of QAnyStringView, I'd like to use it in constexpr contexts

#include <QtCore>

struct Tag
{
    static constexpr Tag fromString(QAnyStringView view) {
        return Tag{view.visit([](auto view){
            return view.size();
        })};
    }

    constexpr qsizetype size() const { return m_size; }

    qsizetype m_size;
};

int main()
{
    constexpr qsizetype size = Tag::fromString(u"abcd").size();
    return 0;
}

main.cpp:18:25: error: constexpr variable 'size' must be initialized by a constant expression
    constexpr qsizetype size = Tag::fromString(u"abcd").size();
                        ^      ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/Users/vohi/qt/dev-build/qtbase/include/QtCore/../../../../dev/qtbase/src/corelib/text/qanystringview.h:324:47: note: read of member 'm_data_utf16' of union with active member 'm_data' is not allowed in a constant expression
    { return Q_ASSERT(isUtf16()), QStringView{m_data_utf16, size()}; }
                                              ^
/Users/vohi/qt/dev-build/qtbase/include/QtCore/../../../../dev/qtbase/src/corelib/text/qstring.h:105:41: note: in call to '&view->asStringView()'
        return std::forward<Visitor>(v)(asStringView());
                                        ^
/Users/vohi/qt/testing/sandbox/main.cpp:6:25: note: in call to '&view->visit([](auto view) {
    return view.size();
})'
        return Tag{view.visit([](auto view){
                        ^
/Users/vohi/qt/testing/sandbox/main.cpp:18:32: note: in call to 'fromString({{.m_data = &u"abcd"[0]}, 9223372036854775812})'
    constexpr qsizetype size = Tag::fromString(u"abcd").size();
                               ^
1 error generated.