func WalkASTWithParent(n ast.Node, f func(n ast.Node, parent ast.Node) bool) {
	var ancestors []ast.Node
	ast.Inspect(n, func(n ast.Node) (recurse bool) {
		if n == nil {
			ancestors = ancestors[:len(ancestors)-1]
			return false
		}

		var parent ast.Node
		if len(ancestors) > 0 {
			parent = ancestors[len(ancestors)-1]
		}
		ancestors = append(ancestors, n)
		return f(n, parent)
	})
}

      a.attr(), b.attr(), [](const string& s) { return s; },
      [](const AttrValue& v) { return v.DebugString(); },
      [](const string& key, const AttrValue& av, const AttrValue& bv) {
        if (key == "ancestors") {
          // The ancestors are added from a set so the order is unpredictable;
          // just compare set equality not list equality.
          std::unordered_set<string> a_set(av.list().s().begin(),

}

// CHECK-LABEL: @RewriteHostComputeMlirOp
func.func @RewriteHostComputeMlirOp(%arg0: tensor<*xf32>, %arg1: tensor<3x?xf64>) -> (tensor<*xf32>) {

  // CHECK: "tf.XlaHostCompute"(%arg0, %arg1)
  // CHECK-SAME: ancestors = []
  // CHECK-SAME: cost_estimate_ns = 1000000 : i64
  // CHECK-SAME: key = ""
  // CHECK-SAME: recv_key = "host_compute_channel_recv"
  // CHECK-SAME: send_key = "host_compute_channel_send"

        return transformer.apply(value);
    }

#foreach ( $class in $model.allClasses )
  #if ( $class.name != "InputSource" && $class.name != "InputLocation" )
    #set ( $ancestors = $Helper.ancestors( $class ) )
    #set ( $allFields = $Helper.xmlFields( $class ) )
    protected ${class.name} transform${class.name}(${class.name} target) {
        if (target == null) {
            return null;
        }

     *
     * A file is contained in the set if it or one of its ancestors has
     * been added to the set.
     */
    public abstract boolean contains(File file);

    /**
     * Checks if the given path is contained in the set.
     *
     * A path is contained in the set if it or one of its ancestors has
     * been added to the set.
     */
    public abstract boolean contains(String path);

// If `use_external_constant` is true, it will create `tfl.external_const`
// instead of `tfl.const`.
// If `experimental_prune_unreachable_nodes_unconditionally` is true, nodes that
// are not ancestors of the output nodes will be pruned.
mlir::OwningOpRef<mlir::ModuleOp> FlatBufferToMlir(
    absl::string_view buffer, mlir::MLIRContext* context,
    mlir::Location base_loc, bool use_external_constant = false,

    visited.insert(item.cluster);

    stack.push_back({item.cluster, true});
    const auto& iter = ancestors.find(item.cluster);
    if (iter != ancestors.end()) {
      for (const auto& ancestor : iter->second) {
        stack.push_back({ancestor, false});
      }
    }
  }
  CHECK(sorted->size() == clusters.size());
}

}  // namespace

#set ( $package = "${packageModelV4}" )
#set ( $root = $model.getClass( $model.getRoot($version), $version ) )
#foreach ( $class in $model.allClasses )
  #set ( $ancestors = $Helper.ancestors( $class ) )
  #set ( $allFields = [] )
  #set ( $inheritedFields = [] )
  #foreach ( $cl in $ancestors )
    #if ( $cl != $class )
      #set ( $dummy = $inheritedFields.addAll( $cl.getFields($version) ) )
    #end

        parent1.ownStrictVersionConstraints != StrictVersionConstraints.EMPTY
        parent2.ownStrictVersionConstraints == StrictVersionConstraints.EMPTY
    }

    def "computes intersection of ancestors"() {
        when:
        def parent1Edge = edge(root, false)
        def parent2Edge = edge(root, false)
        def parent1 = parent1Edge.targetComponent.nodes[0]

}

// Checks if an op is a supported HLO control flow op.
bool IsControlFlowOp(Operation* op) { return isa<IfOp, WhileOp>(op); }

// Collects control flow op ancestors of a given op, up until FuncOp. If any
// ancestor is not a control flow op or a FuncOp, or of a single block region,
// an error will be returned.
LogicalResult GetControlFlowAncestors(