Trouble composing filtered with reverse graph

[andrea-cassioli-maersk]

I need to run some algorithm on the reverse of a filtered graph.

Moreover I have implemented a graph class FG that inherits from a filtered_graph, mainly for the purpose of exposing some types and add some few other things. But overall a plain inheritance.

Combining FG with a reverse_graph does not seem to work. Here a minimal example

#include <boost/graph/adjacency_list.hpp>
#include <boost/graph/filtered_graph.hpp>
#include <boost/graph/reverse_graph.hpp>


template <typename G, typename F>
class FG : public boost::filtered_graph<G, F> {
 public:
  FG(const G& graph, F f)
      : boost::filtered_graph<G, F>(graph, f) {}
};

template <typename G, typename F>
auto GetFG(const G& graph, F f) {
  return FG<G, F>(graph, f);
}

int main() {
  using Graph = boost::adjacency_list<boost::vecS, boost::vecS, boost::directedS, int, int>;

  const Graph graph;
  const auto filtered = GetFG(graph, [](const auto&) { return true; });
  const auto reverse  = boost::make_reverse_graph(filtered);
  auto [eb, ee] = boost::edges(reverse);
  auto e        = *eb;

  if (const auto prop = reverse[e]; prop > 0) {
    throw std::logic_error("");
  }
}

Compiling with clang I get

/Users/andrea.cassioli/.conan2/p/b/boost6b6b51639ca5b/p/include/boost/graph/graph_traits.hpp:334:25: error: no type named 'edge_bundled' in 'FG<boost::adjacency_list<boost::vecS, boost::vecS, boost::directedS, int, int>, (lambda at /Users/andrea.cassioli/workspace/DST-Network-Design/test/benchmark/sandbox/benchmark_main.cpp:43:38)>'
  334 |     typedef typename G::edge_bundled type;
      |             ~~~~~~~~~~~~^~~~~~~~~~~~
/Users/andrea.cassioli/.conan2/p/b/boost6b6b51639ca5b/p/include/boost/graph/graph_traits.hpp:349:30: note: in instantiation of template class 'boost::edge_bundle_type<FG<boost::adjacency_list<boost::vecS, boost::vecS, boost::directedS, int, int>, (lambda at /Users/andrea.cassioli/workspace/DST-Network-Design/test/benchmark/sandbox/benchmark_main.cpp:43:38)>>' requested here
  349 |             typedef typename bundler::type type;
      |                              ^
/Users/andrea.cassioli/.conan2/p/b/boost6b6b51639ca5b/p/include/boost/graph/reverse_graph.hpp:219:29: note: in instantiation of template class 'boost::graph::detail::bundled_result<FG<boost::adjacency_list<boost::vecS, boost::vecS, boost::directedS, int, int>, (lambda at /Users/andrea.cassioli/workspace/DST-Network-Design/test/benchmark/sandbox/benchmark_main.cpp:43:38)>, boost::detail::edge_desc_impl<boost::directed_tag, unsigned long>>' requested here
  219 |     typename graph::detail::bundled_result< BidirectionalGraph,
      |                             ^
/Users/andrea.cassioli/workspace/DST-Network-Design/test/benchmark/sandbox/benchmark_main.cpp:60:32: note: while substituting deduced template arguments into function template 'operator[]' [with Descriptor = reference]
   60 |   if (const auto prop = reverse[e]; prop > 0) {
      |                                ^
/Users/andrea.cassioli/workspace/DST-Network-Design/test/benchmark/sandbox/benchmark_main.cpp:60:32: error: no viable overloaded operator[] for type 'const reverse_graph<FG<adjacency_list<vecS, vecS, directedS, int, int, no_property, listS>, (lambda at /Users/andrea.cassioli/workspace/DST-Network-Design/test/benchmark/sandbox/benchmark_main.cpp:43:38)>>'
   60 |   if (const auto prop = reverse[e]; prop > 0) {
      |                         ~~~~~~~^~
/Users/andrea.cassioli/.conan2/p/b/boost6b6b51639ca5b/p/include/boost/graph/reverse_graph.hpp:212:5: note: candidate function template not viable: 'this' argument has type 'const reverse_graph<FG<adjacency_list<vecS, vecS, directedS, int, int, no_property, listS>, (lambda at /Users/andrea.cassioli/workspace/DST-Network-Design/test/benchmark/sandbox/benchmark_main.cpp:43:38)>>', but method is not marked const
  212 |     operator[](Descriptor x)
      |     ^
/Users/andrea.cassioli/.conan2/p/b/boost6b6b51639ca5b/p/include/boost/graph/reverse_graph.hpp:222:5: note: candidate template ignored: substitution failure [with Descriptor = reference]
  222 |     operator[](Descriptor x) const
      |     ^

Moreover

• Using the plain filtered_graph works.
• Reversing first, filtering then also works.

I am quite puzzle by why my code does not.

I would expect FG to be basically equivalent to filtered_graph.

Any clue? Is it some known limitation? I cannot see anything in the log suggesting

[jeremy-murphy]

You know what, I need to read questions more closely before I go off on long-winded answers.
The problem is that your FG class does not expose the required type aliases to fulfil the graph concept. I think it's because of templates and dependent types, but basically you have to define all those type aliases in your derived class to be equal to the values from the base class. Boring and repetitive, but I'm not sure if it's avoidable.
PS. I deleted my other comments because they were really missing the point. 😅