diff --git a/Generalized_map/include/CGAL/Generalized_map.h b/Generalized_map/include/CGAL/Generalized_map.h
index 541c0619d5a..d8b4bf9b514 100644
--- a/Generalized_map/include/CGAL/Generalized_map.h
+++ b/Generalized_map/include/CGAL/Generalized_map.h
@@ -103,7 +103,8 @@ namespace CGAL {
     typedef typename Base::Use_index Use_index;
     typedef typename Base::Dart_range Dart_range;
     typedef typename Base::Dart_const_range Dart_const_range;
-
+    using Hash_function=typename Base::Hash_function;
+    
     static const size_type NB_MARKS = Base::NB_MARKS;
     static const size_type INVALID_MARK = NB_MARKS;
 
@@ -199,8 +200,8 @@ namespace CGAL {
               typename Converters, typename DartInfoConverter,
               typename PointConverter>
     void generic_copy(GMap2& amap,
-                      std::unordered_map<Dart_handle_2, Dart_handle>* origin_to_copy,
-                      std::unordered_map<Dart_handle, Dart_handle_2>* copy_to_origin,
+                      std::unordered_map<Dart_handle_2, Dart_handle,Hash_function>* origin_to_copy,
+                      std::unordered_map<Dart_handle, Dart_handle_2,Hash_function>* copy_to_origin,
                       const Converters& converters,
                       const DartInfoConverter& dartinfoconverter,
                       const PointConverter& pointconverter,
@@ -231,7 +232,7 @@ namespace CGAL {
       // Create an mapping between darts of the two maps (originals->copies).
       // (here we cannot use CGAL::Unique_hash_map because it does not provide
       // iterators...
-      std::unordered_map<Dart_handle_2, Dart_handle> local_dartmap;
+      std::unordered_map<Dart_handle_2, Dart_handle,Hash_function> local_dartmap;
       if (origin_to_copy==nullptr) // Use local_dartmap if user does not provides its own unordered_map
       { origin_to_copy=&local_dartmap; }
 
@@ -269,7 +270,7 @@ namespace CGAL {
 
       unsigned int min_dim=(dimension<amap.dimension?dimension:amap.dimension);
 
-      typename std::unordered_map<Dart_handle_2, Dart_handle>::iterator
+      typename std::unordered_map<Dart_handle_2, Dart_handle, Hash_function>::iterator
         dartmap_iter, dartmap_iter_end=origin_to_copy->end();
       for (dartmap_iter=origin_to_copy->begin(); dartmap_iter!=dartmap_iter_end;
            ++dartmap_iter)
@@ -305,9 +306,9 @@ namespace CGAL {
              typename PointConverter>
     void copy(GMap2& amap,
               std::unordered_map
-              <typename GMap2::Dart_handle, Dart_handle>* origin_to_copy,
+              <typename GMap2::Dart_handle, Dart_handle, Hash_function>* origin_to_copy,
               std::unordered_map
-              <Dart_handle, typename GMap2::Dart_handle>* copy_to_origin,
+              <Dart_handle, typename GMap2::Dart_handle, Hash_function>* copy_to_origin,
               const Converters& converters,
               const DartInfoConverter& dartinfoconverter,
               const PointConverter& pointconverter,
@@ -327,9 +328,9 @@ namespace CGAL {
              typename PointConverter>
     void copy_from_const(const GMap2& amap,
                          std::unordered_map
-                         <typename GMap2::Dart_const_handle, Dart_handle>* origin_to_copy,
+                         <typename GMap2::Dart_const_handle, Dart_handle, Hash_function>* origin_to_copy,
                          std::unordered_map
-                         <Dart_handle, typename GMap2::Dart_const_handle>* copy_to_origin,
+                         <Dart_handle, typename GMap2::Dart_const_handle, Hash_function>* copy_to_origin,
                          const Converters& converters,
                          const DartInfoConverter& dartinfoconverter,
                          const PointConverter& pointconverter,
@@ -348,9 +349,9 @@ namespace CGAL {
     template<typename GMap2, typename Converters, typename DartInfoConverter>
     void copy(GMap2& amap,
               std::unordered_map
-              <typename GMap2::Dart_handle, Dart_handle>* origin_to_copy,
+              <typename GMap2::Dart_handle, Dart_handle, Hash_function>* origin_to_copy,
               std::unordered_map
-              <Dart_handle, typename GMap2::Dart_handle>* copy_to_origin,
+              <Dart_handle, typename GMap2::Dart_handle, Hash_function>* copy_to_origin,
               const Converters& converters,
               const DartInfoConverter& dartinfoconverter,
               bool copy_marks=true,
@@ -368,9 +369,9 @@ namespace CGAL {
     template <typename GMap2, typename Converters, typename DartInfoConverter>
     void copy_from_const(const GMap2& amap,
                          std::unordered_map
-                         <typename GMap2::Dart_const_handle, Dart_handle>* origin_to_copy,
+                         <typename GMap2::Dart_const_handle, Dart_handle, Hash_function>* origin_to_copy,
                          std::unordered_map
-                         <Dart_handle, typename GMap2::Dart_const_handle>* copy_to_origin,
+                         <Dart_handle, typename GMap2::Dart_const_handle, Hash_function>* copy_to_origin,
                          const Converters& converters,
                          const DartInfoConverter& dartinfoconverter,
                          bool copy_marks=true,
@@ -388,9 +389,9 @@ namespace CGAL {
     template<typename GMap2, typename Converters>
     void copy(GMap2& amap,
               std::unordered_map
-              <typename GMap2::Dart_handle, Dart_handle>* origin_to_copy,
+              <typename GMap2::Dart_handle, Dart_handle, Hash_function>* origin_to_copy,
               std::unordered_map
-              <Dart_handle, typename GMap2::Dart_handle>* copy_to_origin,
+              <Dart_handle, typename GMap2::Dart_handle, Hash_function>* copy_to_origin,
               const Converters& converters,
               bool copy_marks=true,
               bool copy_perforated_darts=false,
@@ -405,9 +406,9 @@ namespace CGAL {
     template <typename GMap2, typename Converters>
     void copy_from_const(const GMap2& amap,
                          std::unordered_map
-                         <typename GMap2::Dart_const_handle, Dart_handle>* origin_to_copy,
+                         <typename GMap2::Dart_const_handle, Dart_handle, Hash_function>* origin_to_copy,
                          std::unordered_map
-                         <Dart_handle, typename GMap2::Dart_const_handle>* copy_to_origin,
+                         <Dart_handle, typename GMap2::Dart_const_handle, Hash_function>* copy_to_origin,
                          const Converters& converters,
                          bool copy_marks=true,
                          bool copy_perforated_darts=false,
@@ -422,9 +423,9 @@ namespace CGAL {
     template<typename GMap2>
     void copy(GMap2& amap,
               std::unordered_map
-              <typename GMap2::Dart_handle, Dart_handle>* origin_to_copy=nullptr,
+              <typename GMap2::Dart_handle, Dart_handle, Hash_function>* origin_to_copy=nullptr,
               std::unordered_map
-              <Dart_handle, typename GMap2::Dart_handle>* copy_to_origin=nullptr,
+              <Dart_handle, typename GMap2::Dart_handle, Hash_function>* copy_to_origin=nullptr,
               bool copy_marks=true,
               bool copy_perforated_darts=false,
               size_type mark_perforated=INVALID_MARK)
@@ -438,9 +439,9 @@ namespace CGAL {
     template <typename GMap2>
     void copy_from_const(const GMap2& amap,
                          std::unordered_map
-                         <typename GMap2::Dart_const_handle, Dart_handle>* origin_to_copy=nullptr,
+                         <typename GMap2::Dart_const_handle, Dart_handle, Hash_function>* origin_to_copy=nullptr,
                          std::unordered_map
-                         <Dart_handle, typename GMap2::Dart_const_handle>* copy_to_origin=nullptr,
+                         <Dart_handle, typename GMap2::Dart_const_handle, Hash_function>* copy_to_origin=nullptr,
                          bool copy_marks=true,
                          bool copy_perforated_darts=false,
                          size_type mark_perforated=INVALID_MARK)
@@ -2488,8 +2489,7 @@ namespace CGAL {
     {
       CGAL_assertion( is_without_boundary(dimension) );
 
-      CGAL::Unique_hash_map< Dart_handle, Dart_handle,
-        typename Self::Hash_function > dual;
+      CGAL::Unique_hash_map< Dart_handle, Dart_handle,Hash_function > dual;
       Dart_handle d, d2, res = amap.null_handle;
 
       // We clear amap. TODO return a new amap ?
@@ -2582,7 +2582,7 @@ namespace CGAL {
       unsigned int i = 0;
       CGAL::Unique_hash_map<Dart_const_handle,
                             typename Map2::Dart_const_handle,
-                            typename Self::Hash_function> bijection;
+                            Hash_function> bijection;
 
       while (match && !toTreat1.empty())
       {
diff --git a/Generalized_map/test/Generalized_map/Generalized_map_3_test.h b/Generalized_map/test/Generalized_map/Generalized_map_3_test.h
index ea8aa8128c7..ee4206dad86 100644
--- a/Generalized_map/test/Generalized_map/Generalized_map_3_test.h
+++ b/Generalized_map/test/Generalized_map/Generalized_map_3_test.h
@@ -107,7 +107,7 @@ bool test_GMAP_3()
 
   trace_test_begin();
   InitDartInfo<GMAP>::run(gmap);
-  /* TODO GMAP gmap2(gmap);
+  GMAP gmap2(gmap);
   if ( !check_number_of_cells_3(gmap2, 12, 20, 9, 2, 1) )
     return false;
   if ( !gmap.is_isomorphic_to(gmap2) )
@@ -115,7 +115,7 @@ bool test_GMAP_3()
     std::cout<<"Error: gmap and gmap2 are not isomorphic (after copy).\n";
     assert(false);
     return false;
-  } */
+  }
 
   trace_test_begin();
   gmap.template close<2>();
@@ -143,12 +143,12 @@ bool test_GMAP_3()
   gmap.template remove_cell<2>(gmap.alpha(dh9, 1, 0, 1, 2));
   if ( !check_number_of_cells_3(gmap, 12, 20, 9, 2, 1) )
     return false;
-  /*TODO if ( !gmap.is_isomorphic_to(gmap2) )
+  if ( !gmap.is_isomorphic_to(gmap2) )
   {
     std::cout<<"Error: gmap and gmap2 are not isomorphic (after close and removals).\n";
     assert(false);
     return false;
-  } */
+  }
   gmap.clear();
 
   if (!test_vertex_insertion(gmap))
diff --git a/Generalized_map/test/Generalized_map/Generalized_map_4_test.h b/Generalized_map/test/Generalized_map/Generalized_map_4_test.h
index 9b2e33d5f99..1efee4f91cc 100644
--- a/Generalized_map/test/Generalized_map/Generalized_map_4_test.h
+++ b/Generalized_map/test/Generalized_map/Generalized_map_4_test.h
@@ -108,7 +108,7 @@ bool test_GMAP_4()
 
   trace_test_begin();
   InitDartInfo<GMAP>::run(gmap);
-  /* TODO GMAP gmap2(gmap);
+  GMAP gmap2(gmap);
   if ( !check_number_of_cells_4(gmap2, 12, 20, 9, 2, 2, 1) )
     return false;
   if ( !gmap.is_isomorphic_to(gmap2) )
@@ -116,7 +116,7 @@ bool test_GMAP_4()
     std::cout<<"Error: gmap and gmap2 are not isomorphic (after copy).\n";
     assert(false);
     return false;
-  } */
+  }
 
   trace_test_begin();
   gmap.template close<2>();
@@ -156,12 +156,12 @@ bool test_GMAP_4()
   if ( !check_number_of_cells_4(gmap, 12, 20, 9, 2, 2, 1) )
     return false;
 
-  /* if ( !gmap.is_isomorphic_to(gmap2) )
+  if ( !gmap.is_isomorphic_to(gmap2) )
   {
     std::cout<<"Error: gmap and gmap2 are not isomorphic (after close and removals).\n";
     assert(false);
     return false;
-  } */
+  }
   gmap.clear();
 
   if (!test_vertex_insertion(gmap))