Description Dietrich Travkin 2012-12-21 04:55:38 EST

When working with QVT-O code, the compiler does not know that EObject is the supertype of all objects.

The reason seems to be the missing inheritance relation in the Ecore meta-model in EMF between EObject and EModelElement and EGenericType. According to the Bug 316894 (https://bugs.eclipse.org/bugs/show_bug.cgi?id=316894), this inheritance relation will remain missing in the meta-model. Consequently, all tools based on the EMF meta-model have to consider this implicit inheritance relation.

As a consequence, code like the following one does not compile due to (assumed) incompliance of mapping operation signatures:


modeltype Ecore uses ecore('http://www.eclipse.org/emf/2002/Ecore');

mapping MyElement::myElementToEcoreElement() : EObject
disjuncts MySpecialElementA::elementA2EClass,
          MySpecialElementB::elementB2EOperation {}

mapping MySpecialElementA::elementA2EClass() : EClass {...}

mapping MySpecialElementB::elementB2EOperation () : EOperation {...}

Steps to reproduce:

1) view the registered Ecore meta-model (http://www.eclipse.org/emf/2002/Ecore) with the Metamodel Explorer of the QVT plug-ins. There is no inheritance relation in EModelElement to EObject.

2) Use the above code or similar to reveal the compilation errors.

Actual behavior:

The above code does not compile. The signatures are told to be not compliant.

Expected behavior:

The above QVT-O code should compile, since EClass and EOperation are subtypes of EObject and, thus, the mapping operation signatures are compliant to the myElementToEcoreElement mapping operation.

Platform:
Eclipse 3.7.2, Build ID: M20120208-0800, QVT Operational plug-ins 3.1.0

Additional information:
More details can be found in the QVT-O forum:
http://www.eclipse.org/forums/index.php/m/992285/#msg_992285