void IVisitor.VisitBefore(CommaJoinSource commaJoinSource)
 {
     this.ParentExists(commaJoinSource);
 }
 void IVisitor.VisitOnSeparator(CommaJoinSource commaJoinSource, int offset, int i)
 {
     this.ParentExists(commaJoinSource);
 }
 void IVisitor.VisitAfter(CommaJoinSource commaJoinSource)
 {
     this.ParentExists(commaJoinSource);
 }