:-1: error: moc_emailaddress.o: in function `QtPrivate::QMetaTypeForType<EmailAddress>::getDefaultCtr()::{lambda(QtPrivate::QMetaTypeInterface const*, void*)#1}::operator()(QtPrivate::QMetaTypeInterface const*, void*) const':

/home/xxxx/projects/qt/build-QWidgetDemo-Desktop_Qt_6_2_0_GCC_64bit-Debug/emailtool/../../../../Qt/6.2.0/gcc_64/include/QtCore/qmetatype.h:2237: error: undefined reference to `EmailAddress::EmailAddress()'

:-1: error: collect2: error: ld returned 1 exit status