Implement petgraph only on a wrappers

Fix ambiguous import

src/hugr/validate.rs

@@ -22,6 +22,7 @@ use crate::ops::{OpTag, OpTrait, OpType, ValidateOp};
 use crate::types::{EdgeKind, Type};
 use crate::{Direction, Hugr, Node, Port};
 
+use super::views::petgraph::PetgraphWrapper;
 use super::views::{HierarchyView, HugrView, SiblingGraph};
 use super::NodeType;
 
@@ -99,7 +100,8 @@ impl<'a, 'b> ValidationContext<'a, 'b> {
     /// The results of this computation should be cached in `self.dominators`.
     /// We don't do it here to avoid mutable borrows.
     fn compute_dominator(&self, parent: Node) -> Dominators<Node> {
-        let region: SiblingGraph = SiblingGraph::new(self.hugr, parent);
+        let region: PetgraphWrapper<SiblingGraph> =
+            PetgraphWrapper::new(SiblingGraph::new(self.hugr, parent));
         let entry_node = self.hugr.children(parent).next().unwrap();
         dominators::simple_fast(&region, entry_node)
     }
@@ -364,7 +366,8 @@ impl<'a, 'b> ValidationContext<'a, 'b> {
             return Ok(());
         };
 
-        let region: SiblingGraph = SiblingGraph::new(self.hugr, parent);
+        let region: PetgraphWrapper<SiblingGraph> =
+            PetgraphWrapper::new(SiblingGraph::new(self.hugr, parent));
         let postorder = Topo::new(&region);
         let nodes_visited = postorder.iter(&region).filter(|n| *n != parent).count();
         let node_count = self.hugr.children(parent).count();

src/hugr/views.rs

@@ -8,6 +8,7 @@ pub mod sibling_subgraph;
 #[cfg(test)]
 mod tests;
 
+pub use self::petgraph::PetgraphWrapper;
 pub use descendants::DescendantsGraph;
 pub use sibling::SiblingGraph;
 pub use sibling_subgraph::SiblingSubgraph;
@@ -22,7 +23,6 @@ use crate::ops::handle::NodeHandle;
 use crate::ops::{FuncDecl, FuncDefn, OpName, OpTag, OpType, DFG};
 use crate::types::{EdgeKind, FunctionType};
 use crate::{Direction, Node, Port};
-use ::petgraph::visit as pv;
 
 /// A trait for inspecting HUGRs.
 /// For end users we intend this to be superseded by region-specific APIs.
@@ -232,19 +232,7 @@ pub trait HugrView: sealed::HugrInternals {
 }
 
 /// A common trait for views of a HUGR hierarchical subgraph.
-pub trait HierarchyView<'a>:
-    HugrView
-    + pv::GraphBase<NodeId = Node>
-    + pv::GraphProp
-    + pv::NodeCount
-    + pv::NodeIndexable
-    + pv::EdgeCount
-    + pv::Visitable
-    + pv::GetAdjacencyMatrix
-    + pv::Visitable
-where
-    for<'g> &'g Self: pv::IntoNeighborsDirected + pv::IntoNodeIdentifiers,
-{
+pub trait HierarchyView<'a>: HugrView {
     /// The base from which the subgraph is derived.
     type Base;
 

src/hugr/views/descendants.rs

@@ -21,8 +21,8 @@ type RegionGraph<'g> = portgraph::view::Region<'g, &'g MultiPortGraph>;
 /// its immediate children.  Prefer using [`SiblingGraph`] when possible,
 /// as it is more efficient.
 ///
-/// Implements the [`HierarchyView`] trait, as well as [`HugrView`] and petgraph's
-/// _visit_ traits, so can be  used interchangeably with [`SiblingGraph`].
+/// Implements the [`HierarchyView`] trait, as well as [`HugrView`], it can be
+/// used interchangeably with [`SiblingGraph`].
 ///
 /// [`SiblingGraph`]: super::SiblingGraph
 pub struct DescendantsGraph<'g, Root = Node, Base = Hugr>