code: @Override
  	public boolean eIsSet(int featureID)
  	{
  		switch (featureID)
  		{
  			case XtypePackage.XFUNCTION_TYPE_REF__PARAM_TYPES:
  				return paramTypes != null && !paramTypes.isEmpty();
  			case XtypePackage.XFUNCTION_TYPE_REF__RETURN_TYPE:
  				return returnType != null;
  			case XtypePackage.XFUNCTION_TYPE_REF__TYPE:
  				return type != null;
  			case XtypePackage.XFUNCTION_TYPE_REF__INSTANCE_CONTEXT:
  				return instanceContext != INSTANCE_CONTEXT_EDEFAULT;
  		}
  		return super.eIsSet(featureID);
  	}
docs: <!-- begin-user-doc -->
  <!-- end-user-doc -->
  @generated