delete(g.destinationEdgeIndex, n.ID())
		return
	}

	// decrement the nodeID->destinationID refcount in the index, if the index exists
	index := g.destinationEdgeIndex[n.ID()]
	if index == nil {
		return
	}
	if destinationEdge, ok := e.(*destinationEdge); ok {
		index.decrement(destinationEdge.DestinationID())
	}
}

// A fastpath for recomputeDestinationIndex_locked for "adding edge case".

		return true, nil
	}

	found := false
	traversal := &traverse.VisitingDepthFirst{
		EdgeFilter: func(edge graph.Edge) bool {
			if destinationEdge, ok := edge.(*destinationEdge); ok {
				if destinationEdge.DestinationID() != nodeVertex.ID() {
					// Don't follow edges leading to other nodes
					return false
				}
				// We found an edge leading to the node we want
				found = true
			}
			// Visit this edge