Undefined variable, type or model: 'Source!EClass'

context GeneralTrace!TraceLinkEnd{

--TraceLinkEnd type must be set
constraint notEmptyLinkEndType{
check: self.type.isDefined
}

-- the type of SourceEnd must be related to one of Source meta-classes
constraint sourceEndType{
guard: self.satisfies('notEmptyLinkEndType') and self.sowner.isDefined()
check:Source!EClass.all.select(c|c.name = self.type.name).size() = 1
message: "The meta-class "+self.type.name+"SourceEnd refers to incorrect element"
}
}

emfMetaModel.getResource().getResourceSet().getPackageRegistry().put(EcorePackage.eINSTANCE.getNsURI(), EcorePackage.eINSTANCE);