Support GCC's -Wconversion -Wfloat-conversion -Warith-conversion -Wsign-conversion warnings.

include/boost/container/detail/flat_tree.hpp

@@ -212,15 +212,16 @@ template<class SequenceContainer, class Iterator, class Compare>
 BOOST_CONTAINER_FORCEINLINE void flat_tree_merge_unique  //has_merge_unique == false
    (SequenceContainer& dest, Iterator first, Iterator last, Compare comp, dtl::false_)
 {
-   typedef typename SequenceContainer::iterator    iterator;
-   typedef typename SequenceContainer::size_type   size_type;
+   typedef typename SequenceContainer::iterator          iterator;
+   typedef typename SequenceContainer::size_type         size_type;
+   typedef typename SequenceContainer::difference_type   difference_type;
 
    size_type const old_sz = dest.size();
    iterator const first_new = dest.insert(dest.cend(), first, last );
    iterator e = boost::movelib::inplace_set_unique_difference(first_new, dest.end(), dest.begin(), first_new, comp);
    dest.erase(e, dest.end());
    dtl::bool_<is_contiguous_container<SequenceContainer>::value> contiguous_tag;
-   (flat_tree_container_inplace_merge)(dest, dest.begin()+old_sz, comp, contiguous_tag);
+   (flat_tree_container_inplace_merge)(dest, dest.begin() + difference_type(old_sz), comp, contiguous_tag);
 }
 
 ///////////////////////////////////////
@@ -263,7 +264,7 @@ BOOST_CONTAINER_FORCEINLINE Iterator
    flat_tree_nth  // has_nth == false
       (SequenceContainer& cont, typename SequenceContainer::size_type n, dtl::false_)
 {
-   return cont.begin()+ n;
+   return cont.begin()+ typename SequenceContainer::difference_type(n);
 }
 
 ///////////////////////////////////////
@@ -1013,7 +1014,7 @@ class flat_tree
          : this->priv_insert_unique_prepare(hint, k, data);
 
       if(!ret.second){
-         ret.first  = this->nth(data.position - this->cbegin());
+         ret.first  = this->nth(size_type(data.position - this->cbegin()));
       }
       else{
          ret.first = this->m_data.m_seq.emplace(data.position, try_emplace_t(), ::boost::forward<KeyType>(key), ::boost::forward<Args>(args)...);
@@ -1079,7 +1080,7 @@ class flat_tree
          : this->priv_insert_unique_prepare(hint, k, data);\
       \
       if(!ret.second){\
-         ret.first  = this->nth(data.position - this->cbegin());\
+         ret.first  = this->nth(size_type(data.position - this->cbegin()));\
       }\
       else{\
          ret.first = this->m_data.m_seq.emplace(data.position, try_emplace_t(), ::boost::forward<KeyType>(key) BOOST_MOVE_I##N BOOST_MOVE_FWD##N);\
@@ -1102,7 +1103,7 @@ class flat_tree
          ? this->priv_insert_unique_prepare(k, data)
          : this->priv_insert_unique_prepare(hint, k, data);
       if(!ret.second){
-         ret.first  = this->nth(data.position - this->cbegin());
+         ret.first  = this->nth(size_type(data.position - this->cbegin()));
          ret.first->second = boost::forward<M>(obj);
       }
       else{
@@ -1234,7 +1235,7 @@ class flat_tree
       size_type count(const key_type& k) const
    {
       std::pair<const_iterator, const_iterator> p = this->equal_range(k);
-      size_type n = p.second - p.first;
+      size_type n = size_type(p.second - p.first);
       return n;
    }
 
@@ -1244,7 +1245,7 @@ class flat_tree
       count(const K& k) const
    {
       std::pair<const_iterator, const_iterator> p = this->equal_range(k);
-      size_type n = p.second - p.first;
+      size_type n = size_type(p.second - p.first);
       return n;
    }
 
@@ -1588,7 +1589,7 @@ class flat_tree
       while (len) {
          size_type step = len >> 1;
          middle = first;
-         middle += step;
+         middle += difference_type(step);
 
          if (key_cmp(key_extract(*middle), key)) {
             first = ++middle;
@@ -1613,7 +1614,7 @@ class flat_tree
       while (len) {
          size_type step = len >> 1;
          middle = first;
-         middle += step;
+         middle += difference_type(step);
 
          if (key_cmp(key, key_extract(*middle))) {
             len = step;
@@ -1638,7 +1639,7 @@ class flat_tree
       while (len) {
          size_type step = len >> 1;
          middle = first;
-         middle += step;
+         middle += difference_type(step);
 
          if (key_cmp(key_extract(*middle), key)){
             first = ++middle;
@@ -1650,7 +1651,7 @@ class flat_tree
          else {
             //Middle is equal to key
             last = first;
-            last += len;
+            last += difference_type(len);
             RanIt const first_ret = this->priv_lower_bound(first, middle, key);
             return std::pair<RanIt, RanIt>
                ( first_ret, this->priv_upper_bound(++middle, last, key));