* We perform an equivalency check on two subgraphs by traversing through them * in lockstep. If a given node is equivalent in both the parent and the child, * we mark it in both subgraphs, using the t_emark field, with a monotonically * increasing number. If, in the course of the traversal, we reach a node that * we have visited and numbered during this equivalency check, we have a cycle. *
source not stored for this graph (policy: none)
nothing calls this directly
no test coverage detected