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 | use rustc_index::vec::Idx;
pub mod dominators;
pub mod implementation;
pub mod iterate;
mod reference;
pub mod scc;
pub mod vec_graph;
#[cfg(test)]
mod tests;
pub trait DirectedGraph {
    type Node: Idx;
}
pub trait WithNumNodes: DirectedGraph {
    fn num_nodes(&self) -> usize;
}
pub trait WithNumEdges: DirectedGraph {
    fn num_edges(&self) -> usize;
}
pub trait WithSuccessors: DirectedGraph
where
    Self: for<'graph> GraphSuccessors<'graph, Item = <Self as DirectedGraph>::Node>,
{
    fn successors(&self, node: Self::Node) -> <Self as GraphSuccessors<'_>>::Iter;
    fn depth_first_search(&self, from: Self::Node) -> iterate::DepthFirstSearch<'_, Self>
    where
        Self: WithNumNodes,
    {
        iterate::DepthFirstSearch::new(self).with_start_node(from)
    }
}
#[allow(unused_lifetimes)]
pub trait GraphSuccessors<'graph> {
    type Item;
    type Iter: Iterator<Item = Self::Item>;
}
pub trait WithPredecessors: DirectedGraph
where
    Self: for<'graph> GraphPredecessors<'graph, Item = <Self as DirectedGraph>::Node>,
{
    fn predecessors(&self, node: Self::Node) -> <Self as GraphPredecessors<'_>>::Iter;
}
#[allow(unused_lifetimes)]
pub trait GraphPredecessors<'graph> {
    type Item;
    type Iter: Iterator<Item = Self::Item>;
}
pub trait WithStartNode: DirectedGraph {
    fn start_node(&self) -> Self::Node;
}
pub trait ControlFlowGraph:
    DirectedGraph + WithStartNode + WithPredecessors + WithSuccessors + WithNumNodes
{
    // convenient trait
}
impl<T> ControlFlowGraph for T where
    T: DirectedGraph + WithStartNode + WithPredecessors + WithSuccessors + WithNumNodes
{
}
/// Returns `true` if the graph has a cycle that is reachable from the start node.
pub fn is_cyclic<G>(graph: &G) -> bool
where
    G: ?Sized + DirectedGraph + WithStartNode + WithSuccessors + WithNumNodes,
{
    iterate::TriColorDepthFirstSearch::new(graph)
        .run_from_start(&mut iterate::CycleDetector)
        .is_some()
}
 |