If you have a property of an unknown type, that will create problems later on. The same holds for method arguments, return types and underlying types of enums. qmltyperegistrar now warns about those. When scanning the types, we consider a type potentially primitive if it is not the root type, but one of: a, a self-extending value type b, a type with a JavaScript extension c, a sequence type If those types are found to be "missing" later, we ignore them. All other missing types trigger warnings now. Since we use types from QPA headers in a few places, we now need to recognize QPA headers when looking for private Qt includes. Task-number: QTBUG-101143 Change-Id: Ic4350e8ed46212c0f4af6f10e86323514f710e1e Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>