private bool IsSomeParentLinked(
INode sourceNode,
INode itsChildNode)
{
// Is any of these children actually a parent of node in question?
var otherChildren = new HashSet <INode>(sourceNode.Children);
otherChildren.Remove(itsChildNode);
// The whole parent tree of the particular child node in question. We don't go earlier than the source node.
IEnumerable <INode> parents = _walker.EnumerateAllParentsBreadthFirst(itsChildNode, dontGoEarlierThan: sourceNode);
// Is any of them linked from other children of source node?
bool someParentIsLinked = parents.Any(otherChildren.Contains);
return(someParentIsLinked);
}
