Ensure named_graph base class is initialized before accessing it

include/boost/graph/adjacency_list.hpp

@@ -267,18 +267,21 @@ template < class OutEdgeListS = vecS, // a Sequence or an AssociativeContainer
     class EdgeProperty = no_property, class GraphProperty = no_property,
     class EdgeListS = listS >
 class adjacency_list
-: public detail::adj_list_gen<
-      adjacency_list< OutEdgeListS, VertexListS, DirectedS, VertexProperty,
-          EdgeProperty, GraphProperty, EdgeListS >,
-      VertexListS, OutEdgeListS, DirectedS, VertexProperty, EdgeProperty,
-      GraphProperty, EdgeListS >::type,
-  // Support for named vertices
+: // Support for named vertices
+  // This needs to be inherited from first to ensure it's initialized before the
+  // "base" (i.e. detail::adj_list_gen), because the "base" might indirectly
+  // call functions on it during its construction.
   public graph::maybe_named_graph<
       adjacency_list< OutEdgeListS, VertexListS, DirectedS, VertexProperty,
           EdgeProperty, GraphProperty, EdgeListS >,
       typename adjacency_list_traits< OutEdgeListS, VertexListS, DirectedS,
           EdgeListS >::vertex_descriptor,
-      VertexProperty >
+      VertexProperty >,
+ public detail::adj_list_gen<
+      adjacency_list< OutEdgeListS, VertexListS, DirectedS, VertexProperty,
+          EdgeProperty, GraphProperty, EdgeListS >,
+      VertexListS, OutEdgeListS, DirectedS, VertexProperty, EdgeProperty,
+      GraphProperty, EdgeListS >::type
 {
 public:
     typedef GraphProperty graph_property_type;

test/named_vertices_test.cpp

@@ -91,5 +91,8 @@ int main(int, char*[])
 
     BOOST_TEST(map[*find_vertex("Cincinnatti", map)].population == -1);
 
+    // Ensure copy constructor properly initializes base classes.
+    BOOST_TEST_NO_THROW(RoadMap{map});
+
     return boost::report_errors();
 }