qtestcase.h may need a fix to avoid unreachable code warning.

    inline typename std::enable_if<!QtPrivate::IsQEnumHelper<T>::Value && !std::is_enum_v<T>, char *>::type toString(const T &t)
    {
#ifndef QT_NO_DEBUG_STREAM
        if constexpr (QTypeTraits::has_ostream_operator_v<QDebug, T>) {
            return qstrdup(QDebug::toString(t).toUtf8().constData());
        } else {
            static_assert(!QMetaTypeId2<T>::IsBuiltIn,
                        "Built-in type must implement debug streaming operator "
                        "or provide QTest::toString specialization");
        }
#endif
        return nullptr;
    }