pub(super) fn with_buffered_edge_filter<'g>(
        graph: &'g Graph<G::Node, G::Edge, Directed, G::Ix>,
        params: QueryParams<G>,
        filter: impl BufferedEdgeFilter<&'g Graph<G::Node, G::Edge, Directed, G::Ix>>,
    ) -> Self {
        let (included, len) = match params {
            QueryParams::Forward(initials) => {
                reachable_map_buffered_filter(graph, filter, initials.into_inner())
            }
            QueryParams::Reverse(initials) => reachable_map_buffered_filter(
                Reversed(graph),
                ReversedBufferedFilter(filter),
                initials.into_inner(),
            ),
        };
        Self {
            included,
            len,
            _phantom: PhantomData,
        }
    }
The arguments to the edge filter are the (source, target, edge ix), unreversed.
guppy/src/graph/resolve_core.rs