Fix "count" with heterogeneous lookups in flat_map and flat_set

include/boost/container/detail/flat_tree.hpp

@@ -1605,7 +1605,7 @@ class flat_tree
       const Compare &key_cmp = this->m_data.get_comp();
       KeyOfValue key_extract;
       RanIt lb(this->priv_lower_bound(first, last, k)), ub(lb);
-      if(lb != last && static_cast<difference_type>(!key_cmp(k, key_extract(*lb)))){
+      if(lb != last && !key_cmp(k, key_extract(*lb))){
          ++ub;
       }
       return std::pair<RanIt, RanIt>(lb, ub);

include/boost/container/flat_map.hpp

@@ -1343,7 +1343,9 @@ class flat_map
    //!
    //! <b>Complexity</b>: log(size())+count(k)
    BOOST_CONTAINER_FORCEINLINE size_type count(const key_type& x) const
-      {  return static_cast<size_type>(m_flat_tree.find(x) != m_flat_tree.end());  }
+      //Don't use find() != end optimization here as transparent comparators with key K might
+      //return a different range than key_type (which can only return a single element range)
+      {  return m_flat_tree.count(x);  }
 
    //! <b>Requires</b>: This overload is available only if
    //! key_compare::is_transparent exists.
@@ -1465,6 +1467,8 @@ class flat_map
    //! <b>Complexity</b>: Logarithmic.
    template<class K>
    BOOST_CONTAINER_FORCEINLINE std::pair<iterator,iterator> equal_range(const K& x)
+      //Don't use lower_bound_range optimization here as transparent comparators with key K might
+      //return a different range than key_type (which can only return a single element range)
       {  return dtl::force_copy<std::pair<iterator,iterator> >(m_flat_tree.equal_range(x)); }
 
    //! <b>Requires</b>: This overload is available only if
@@ -1475,6 +1479,8 @@ class flat_map
    //! <b>Complexity</b>: Logarithmic.
    template<class K>
    BOOST_CONTAINER_FORCEINLINE std::pair<const_iterator, const_iterator> equal_range(const K& x) const
+      //Don't use lower_bound_range optimization here as transparent comparators with key K might
+      //return a different range than key_type (which can only return a single element range)
       {  return dtl::force_copy<std::pair<const_iterator,const_iterator> >(m_flat_tree.equal_range(x)); }
 
    //! <b>Effects</b>: Extracts the internal sequence container.

include/boost/container/flat_set.hpp

@@ -925,7 +925,9 @@ class flat_set
    //! <b>Complexity</b>: log(size())+count(k)
    template<typename K>
    BOOST_CONTAINER_FORCEINLINE size_type count(const K& x) const
-   {  return static_cast<size_type>(this->tree_t::find(x) != this->tree_t::cend());  }
+      //Don't use find() != end optimization here as transparent comparators with key K might
+      //return a different range than key_type (which can only return a single element range)
+   {  return this->tree_t::count(x);  }
 
    #if defined(BOOST_CONTAINER_DOXYGEN_INVOKED)
 
@@ -1031,6 +1033,8 @@ class flat_set
    //! <b>Complexity</b>: Logarithmic
    template<typename K>
    std::pair<iterator,iterator> equal_range(const K& x)
+      //Don't use lower_bound_range optimization here as transparent comparators with key K might
+      //return a different range than key_type (which can only return a single element range)
    {  return this->tree_t::equal_range(x);  }
 
    //! <b>Requires</b>: This overload is available only if
@@ -1041,6 +1045,8 @@ class flat_set
    //! <b>Complexity</b>: Logarithmic
    template<typename K>
    std::pair<const_iterator,const_iterator> equal_range(const K& x) const
+      //Don't use lower_bound_range optimization here as transparent comparators with key K might
+      //return a different range than key_type (which can only return a single element range)
    {  return this->tree_t::equal_range(x);  }
 
    #if defined(BOOST_CONTAINER_DOXYGEN_INVOKED)