Proposed resolution:

The wording refers to N3126.

1. Change 23.7.1 Class template unordered_map [unord.map]/3, as indicated:

     namespace std {
       template <class Key,
         class T,
         class Hash = hash<Key>,
         class Pred = std::equal_to<Key>,
         class Alloc = std::allocator<std::pair<const Key, T> > >
       class unordered_map
       {
       public:
         [..]
         // bucket interface
         size_type bucket_count() const;
         size_type max_bucket_count() const;
         size_type bucket_size(size_type n) const;
         [..]
   

2. Change 23.7.2 Class template unordered_multimap [unord.multimap]/3, as indicated:

     namespace std {
       template <class Key,
         class T,
         class Hash = hash<Key>,
         class Pred = std::equal_to<Key>,
         class Alloc = std::allocator<std::pair<const Key, T> > >
       class unordered_multimap
       {
       public:
         [..]
         // bucket interface
         size_type bucket_count() const;
         size_type max_bucket_count() const;
         size_type bucket_size(size_type n) const;
         [..]
   

3. Change 23.7.4 Class template unordered_multiset [unord.multiset]/3, as indicated:

     namespace std {
       template <class Key,
         class Hash = hash<Key>,
         class Pred = std::equal_to<Key>,
         class Alloc = std::allocator<Key> >
       class unordered_multiset
       {
       public:
         [..]
         // bucket interface
         size_type bucket_count() const;
         size_type max_bucket_count() const;
         size_type bucket_size(size_type n) const;
         [..]
   

[ Adopted at 2010-11 Batavia ]

[ Post-Rapperswil ]

Moved to Tentatively Ready after 5 positive votes on c++std-lib.

While bucket_size() is const for unordered_set, for all other unordered containers it is not defined as constant member function.