System.Xml.Schema.Compiler.IsElementFromGroupBase C# (CSharp) Метод

        private bool IsElementFromGroupBase(XmlSchemaElement derivedElement, XmlSchemaGroupBase baseGroupBase) {
            if (baseGroupBase is XmlSchemaSequence) {
                XmlSchemaSequence virtualSeq = new XmlSchemaSequence();
                virtualSeq.MinOccurs = 1;
                virtualSeq.MaxOccurs = 1;
                virtualSeq.Items.Add(derivedElement);
                if (IsGroupBaseFromGroupBase((XmlSchemaGroupBase)virtualSeq, baseGroupBase, true)) {
                    return true;
                }
                restrictionErrorMsg = Res.GetString(Res.Sch_ElementFromGroupBase1, derivedElement.QualifiedName.ToString(), derivedElement.LineNumber.ToString(NumberFormatInfo.InvariantInfo), derivedElement.LinePosition.ToString(NumberFormatInfo.InvariantInfo), baseGroupBase.LineNumber.ToString(NumberFormatInfo.InvariantInfo), baseGroupBase.LinePosition.ToString(NumberFormatInfo.InvariantInfo));
            }
            else if (baseGroupBase is XmlSchemaChoice) {
                XmlSchemaChoice virtualChoice = new XmlSchemaChoice();
                virtualChoice.MinOccurs = 1;
                virtualChoice.MaxOccurs = 1;
                virtualChoice.Items.Add(derivedElement);
                if (IsGroupBaseFromGroupBase((XmlSchemaGroupBase)virtualChoice, baseGroupBase, false)) {
                    return true;
                }
                restrictionErrorMsg = Res.GetString(Res.Sch_ElementFromGroupBase2, derivedElement.QualifiedName.ToString(), derivedElement.LineNumber.ToString(NumberFormatInfo.InvariantInfo), derivedElement.LinePosition.ToString(NumberFormatInfo.InvariantInfo), baseGroupBase.LineNumber.ToString(NumberFormatInfo.InvariantInfo), baseGroupBase.LinePosition.ToString(NumberFormatInfo.InvariantInfo));
            }
            else if (baseGroupBase is XmlSchemaAll) {
                XmlSchemaAll virtualAll = new XmlSchemaAll();
                virtualAll.MinOccurs = 1;
                virtualAll.MaxOccurs = 1;
                virtualAll.Items.Add(derivedElement);
                if (IsGroupBaseFromGroupBase((XmlSchemaGroupBase)virtualAll, baseGroupBase, true)) {
                    return true;
                }
                restrictionErrorMsg = Res.GetString(Res.Sch_ElementFromGroupBase3, derivedElement.QualifiedName.ToString(), derivedElement.LineNumber.ToString(NumberFormatInfo.InvariantInfo), derivedElement.LinePosition.ToString(NumberFormatInfo.InvariantInfo), baseGroupBase.LineNumber.ToString(NumberFormatInfo.InvariantInfo), baseGroupBase.LinePosition.ToString(NumberFormatInfo.InvariantInfo));
            }
            return false;
        }