UML23 — UML 2.2 Issue - availability of PrimitiveTypes for UML models

The introduction to section 17.4 states the following:

A number of primitive types have been defined for use in the specification of the UML metamodel. These include

primitive types such as Integer, Boolean, and String. These types are reused by both MOF and UML, and may potentially

be reused also in user models.

However the XMI for UML provides the definitions only as CMOF types not as UML types – so they cannot reliably/interchangeably be used/reused or referenced from user models. There would also need to be a normative URI defined for them.

Indeed for better interchange of UML user models, there needs to be a normative PrimitiveTypes package (with a normative URI) with the common primitive types that can be referenced by UML XMI documents.
Additionally, since such primitive types are also needed by almost all CMOF-based metamodels, a PrimitiveTypes CMOF package is needed. Unfortunately, the PrimitiveTypes package provided in the InfrastructureLibrary is meant to be package merged vs. referenced by metamodels. Since only few metamodels merge it (still resulting in private copies), the rest duplicate these primitive types in their context.
This resolution proposes moving the PrimitiveTypes package out of InfrastructureLibrary.cmof and into its own independent package (PrimitiveTypes.cmof). This package can then be referenced instead of copied (through package merge) by metamodels. Additionally, the package can also be exported in UML XMI as PrimitiveTypes.xmi, to be referenced by user models.