// bslstl_unorderedset_cpp03.h                                        -*-C++-*-

// Automatically generated file.  **DO NOT EDIT**

#ifndef INCLUDED_BSLSTL_UNORDEREDSET_CPP03
#define INCLUDED_BSLSTL_UNORDEREDSET_CPP03

//@PURPOSE: Provide C++03 implementation for bslstl_unorderedset.h
//
//@CLASSES: See bslstl_unorderedset.h for list of classes
//
//@SEE_ALSO: bslstl_unorderedset
//
//@DESCRIPTION:  This component is the C++03 translation of a C++11 component,
// generated by the 'sim_cpp11_features.pl' program.  If the original header
// contains any specially delimited regions of C++11 code, then this generated
// file contains the C++03 equivalent, i.e., with variadic templates expanded
// and rvalue-references replaced by 'bslmf::MovableRef' objects.  The header
// code in this file is designed to be '#include'd into the original header
// when compiling with a C++03 compiler.  If there are no specially delimited
// regions of C++11 code, then this header contains no code and is not
// '#include'd in the original header.
//
// Generated on Thu Mar 19 20:53:55 2026
// Command line: sim_cpp11_features.pl bslstl_unorderedset.h

#ifdef COMPILING_BSLSTL_UNORDEREDSET_H

namespace bsl {

                        // ===================
                        // class unordered_set
                        // ===================

/// This class template implements a value-semantic container type holding
/// an unordered set of unique values (of template parameter type `KEY`).
///
/// This class:
/// * supports a complete set of *value-semantic* operations
///   - except for BDEX serialization
/// * is *exception-neutral* (agnostic except for the `at` method)
/// * is *alias-safe*
/// * is `const` *thread-safe*
/// For terminology see {`bsldoc_glossary`}.
template <class KEY,
          class HASH  = bsl::hash<KEY>,
          class EQUAL = bsl::equal_to<KEY>,
          class ALLOCATOR = bsl::allocator<KEY> >
class unordered_set {

  private:

    // PRIVATE TYPES

    /// This typedef is an alias for the allocator traits type associated
    /// with this container.
    typedef bsl::allocator_traits<ALLOCATOR>                 AllocatorTraits;

    /// This typedef is an alias for the type of values maintained by this
    /// unordered set.
    typedef KEY                                              ValueType;

    /// This typedef is an alias for the policy used internally by this
    /// container to extract the `KEY` value from the values maintained by
    /// this unordered set.
    typedef ::BloombergLP::bslstl::UnorderedSetKeyConfiguration<ValueType>
                                                             ListConfiguration;

    /// This typedef is an alias for the template instantiation of the
    /// underlying `bslstl::HashTable` used to implement this set.
    typedef ::BloombergLP::bslstl::HashTable<ListConfiguration,
                                             HASH,
                                             EQUAL,
                                             ALLOCATOR>      HashTable;

    /// This typedef is an alias for the type of links maintained by the
    /// linked list of elements held by the underlying `bslstl::HashTable`.
    typedef ::BloombergLP::bslalg::BidirectionalLink         HashTableLink;

    /// This typedef is a convenient alias for the utility associated with
    /// movable references.
    typedef BloombergLP::bslmf::MovableRefUtil               MoveUtil;

    // FRIEND
    template <class KEY2,
              class HASH2,
              class EQUAL2,
              class ALLOCATOR2>
    friend bool operator==(
                        const unordered_set<KEY2, HASH2, EQUAL2, ALLOCATOR2>&,
                        const unordered_set<KEY2, HASH2, EQUAL2, ALLOCATOR2>&);

  public:
    // PUBLIC TYPES
    typedef KEY                                        key_type;
    typedef KEY                                        value_type;
    typedef HASH                                       hasher;
    typedef EQUAL                                      key_equal;
    typedef ALLOCATOR                                  allocator_type;
    typedef value_type&                                reference;
    typedef const value_type&                          const_reference;

    typedef typename AllocatorTraits::size_type        size_type;
    typedef typename AllocatorTraits::difference_type  difference_type;
    typedef typename AllocatorTraits::pointer          pointer;
    typedef typename AllocatorTraits::const_pointer    const_pointer;
    typedef ::BloombergLP::bslstl::HashTableIterator<
                    const value_type, difference_type> iterator;
    typedef ::BloombergLP::bslstl::HashTableBucketIterator<
                    const value_type, difference_type> local_iterator;

    typedef iterator                                   const_iterator;
    typedef local_iterator                             const_local_iterator;

  public:
    // TRAITS
    BSLMF_NESTED_TRAIT_DECLARATION_IF(
                    unordered_set,
                    ::BloombergLP::bslmf::IsBitwiseMoveable,
                    ::BloombergLP::bslmf::IsBitwiseMoveable<HashTable>::value);

  private:
    // DATA
    HashTable  d_impl;

  public:
    // CREATORS

    /// Create an empty unordered set.  Optionally specify an
    /// `initialNumBuckets` indicating the initial size of the array of
    /// buckets of this container.  If `initialNumBuckets` is not supplied,
    /// a single bucket is used.  Optionally specify a `hashFunction` used
    /// to generate the hash values for the keys contained in this set.  If
    /// `hashFunction` is not supplied, a default-constructed object of the
    /// (template parameter) type `HASH` is used.  Optionally specify a
    /// key-equality functor `keyEqual` used to verify that two key are
    /// equivalent.  If `keyEqual` is not supplied, a default-constructed
    /// object of the (template parameter) type `EQUAL` is used.  Optionally
    /// specify a `basicAllocator` used to supply memory.  If
    /// `basicAllocator` is not supplied, a default-constructed object of
    /// the (template parameter) type `ALLOCATOR` is used.  If the type
    /// `ALLOCATOR` is `bsl::allocator` and `basicAllocator` is not
    /// supplied, the currently installed default allocator is used to
    /// supply memory.  Note that a `bslma::Allocator *` can be supplied for
    /// `basicAllocator` if the type `ALLOCATOR` is `bsl::allocator` (the
    /// default).
    unordered_set();
    explicit unordered_set(size_type        initialNumBuckets,
                           const HASH&      hashFunction = HASH(),
                           const EQUAL&     keyEqual = EQUAL(),
                           const ALLOCATOR& basicAllocator = ALLOCATOR());
    unordered_set(size_type        initialNumBuckets,
                  const HASH&      hashFunction,
                  const ALLOCATOR& basicAllocator);
    unordered_set(size_type        initialNumBuckets,
                  const ALLOCATOR& basicAllocator);
    explicit unordered_set(const ALLOCATOR& basicAllocator);

    /// Create an unordered set having the same value as the specified
    /// `original` object.  Use a copy of `original.hash_function()` to
    /// generate hash values for the keys contained in this set.  Use a copy
    /// of `original.key_eq()` to verify that two keys are equivalent.  Use
    /// the allocator returned by `bsl::allocator_traits<ALLOCATOR>::
    /// select_on_container_copy_construction(original.get_allocator())` to
    /// allocate memory.  This method requires that the (template parameter)
    /// type `KEY` be `copy-insertable` into this set (see {Requirements on
    /// `KEY`}).
    unordered_set(const unordered_set& original);

    /// Create an unordered set having the same value as the specified
    /// `original` object by moving (in constant time) the contents of
    /// `original` to the new set.  Use a copy of `original.hash_function()`
    /// to generate hash values for the keys contained in this set.  Use a
    /// copy of `original.key_eq()` to verify that two keys are equivalent.
    /// The allocator associated with `original` is propagated for use in
    /// the newly-created set.  `original` is left in a valid but
    /// unspecified state.
    unordered_set(BloombergLP::bslmf::MovableRef<unordered_set> original);

    /// Create an unordered set having the same value as the specified
    /// `original` object that uses the specified `basicAllocator` to supply
    /// memory.  Use a copy of `original.hash_function()` to generate hash
    /// values for the keys contained in this set.  Use a copy of
    /// `original.key_eq()` to verify that two keys are equivalent.  This
    /// method requires that the (template parameter) type `KEY` be
    /// `copy-insertable` into this set (see {Requirements on `KEY`}).  Note
    /// that a `bslma::Allocator *` can be supplied for `basicAllocator` if
    /// the (template parameter) type `ALLOCATOR` is `bsl::allocator` (the
    /// default).
    unordered_set(
                const unordered_set&                           original,
                const typename type_identity<ALLOCATOR>::type& basicAllocator);

    /// Create an unordered set having the same value as the specified
    /// `original` object that uses the specified `basicAllocator` to supply
    /// memory.  The contents of `original` are moved (in constant time) to
    /// the new set if `basicAllocator == original.get_allocator()`, and are
    /// move-inserted (in linear time) using `basicAllocator` otherwise.
    /// `original` is left in a valid but unspecified state.  Use a copy of
    /// `original.hash_function()` to generate hash values for the keys
    /// contained in this set.  Use a copy of `original.key_eq()` to verify
    /// that two keys are equivalent.  This method requires that the
    /// (template parameter) type `KEY` be `move-insertable` (see
    /// {Requirements on `KEY`}).  Note that a `bslma::Allocator *` can be
    /// supplied for `basicAllocator` if the (template parameter) type
    /// `ALLOCATOR` is `bsl::allocator` (the default).
    unordered_set(
                BloombergLP::bslmf::MovableRef<unordered_set>  original,
                const typename type_identity<ALLOCATOR>::type& basicAllocator);

    /// Create an unordered set, and insert each `value_type` object in the
    /// sequence starting at the specified `first` element, and ending
    /// immediately before the specified `last` element, ignoring those keys
    /// having a value equivalent to that which appears earlier in the
    /// sequence.  Optionally specify an `initialNumBuckets` indicating the
    /// initial size of the array of buckets of this container.  If
    /// `initialNumBuckets` is not supplied, a single bucket is used.
    /// Optionally specify a `hashFunction` used to generate hash values for
    /// the keys contained in this set.  If `hashFunction` is not supplied,
    /// a default-constructed object of (template parameter) type `HASH` is
    /// used.  Optionally specify a key-equality functor `keyEqual` used to
    /// verify that two key values are the same.  If `keyEqual` is not
    /// supplied, a default-constructed object of (template parameter) type
    /// `EQUAL` is used.  Optionally specify a `basicAllocator` used to
    /// supply memory.  If `basicAllocator` is not supplied, a
    /// default-constructed object of the (template parameter) type
    /// `ALLOCATOR` is used.  If the type `ALLOCATOR` is `bsl::allocator`
    /// and `basicAllocator` is not supplied, the currently installed
    /// default allocator is used to supply memory.  The (template
    /// parameter) type `INPUT_ITERATOR` shall meet the requirements of an
    /// input iterator defined in the C++11 standard [24.2.3] providing
    /// access to values of a type convertible to `value_type`, and
    /// `value_type` must be `emplace-constructible` from `*i` into this
    /// unordered set, where `i` is a dereferenceable iterator in the range
    /// `[first .. last)` (see {Requirements on `KEY`}).  The behavior is
    /// undefined unless `first` and `last` refer to a sequence of valid
    /// values where `first` is at a position at or before `last`.  Note
    /// that a `bslma::Allocator *` can be supplied for `basicAllocator` if
    /// the type `ALLOCATOR` is `bsl::allocator` (the default).
    template <class INPUT_ITERATOR>
    unordered_set(INPUT_ITERATOR   first,
                  INPUT_ITERATOR   last,
                  size_type        initialNumBuckets = 0,
                  const HASH&      hashFunction = HASH(),
                  const EQUAL&     keyEqual = EQUAL(),
                  const ALLOCATOR& basicAllocator = ALLOCATOR());
    template <class INPUT_ITERATOR>
    unordered_set(INPUT_ITERATOR   first,
                  INPUT_ITERATOR   last,
                  size_type        initialNumBuckets,
                  const HASH&      hashFunction,
                  const ALLOCATOR& basicAllocator);
    template <class INPUT_ITERATOR>
    unordered_set(INPUT_ITERATOR   first,
                  INPUT_ITERATOR   last,
                  size_type        initialNumBuckets,
                  const ALLOCATOR& basicAllocator);
    template <class INPUT_ITERATOR>
    unordered_set(INPUT_ITERATOR   first,
                  INPUT_ITERATOR   last,
                  const ALLOCATOR& basicAllocator);

#if defined(BSLS_COMPILERFEATURES_SUPPORT_GENERALIZED_INITIALIZERS)
# ifdef BSLS_COMPILERFEATURES_SUPPORT_CTAD
    template <
    class = bsl::enable_if_t<std::is_invocable_v<HASH, const KEY &>>,
    class = bsl::enable_if_t<
                         std::is_invocable_v<EQUAL, const KEY &, const KEY &>>,
    class = bsl::enable_if_t< bsl::IsStdAllocator_v<ALLOCATOR>>
    >
# endif
    unordered_set(std::initializer_list<KEY> values,
                  size_type                  initialNumBuckets = 0,
                  const HASH&                hashFunction = HASH(),
                  const EQUAL&               keyEqual = EQUAL(),
                  const ALLOCATOR&           basicAllocator = ALLOCATOR());
# ifdef BSLS_COMPILERFEATURES_SUPPORT_CTAD
    template <
    class = bsl::enable_if_t<std::is_invocable_v<HASH, const KEY &>>,
    class = bsl::enable_if_t<bsl::IsStdAllocator<ALLOCATOR>::value>
    >
# endif
    unordered_set(std::initializer_list<KEY> values,
                  size_type                  initialNumBuckets,
                  const HASH&                hashFunction,
                  const ALLOCATOR&           basicAllocator);
# ifdef BSLS_COMPILERFEATURES_SUPPORT_CTAD
    template <class = bsl::enable_if_t<bsl::IsStdAllocator<ALLOCATOR>::value>>
# endif
    unordered_set(std::initializer_list<KEY> values,
                  size_type                  initialNumBuckets,
                  const ALLOCATOR&           basicAllocator);
# ifdef BSLS_COMPILERFEATURES_SUPPORT_CTAD
    /// Create an unordered set and insert each `value_type` object in the
    /// specified `values` initializer list, ignoring those keys having a
    /// value equivalent to that which appears earlier in the list.
    /// Optionally specify an `initialNumBuckets` indicating the initial
    /// size of the array of buckets of this container.  If
    /// `initialNumBuckets` is not supplied, a single bucket is used.
    /// Optionally specify a `hashFunction` used to generate the hash values
    /// for the keys contained in this set.  If `hashFunction` is not
    /// supplied, a default-constructed object of the (template parameter)
    /// type `HASH` is used.  Optionally specify a key-equality functor
    /// `keyEqual` used to verify that two keys are equivalent.  If
    /// `keyEqual` is not supplied, a default-constructed object of the
    /// (template parameter) type `EQUAL` is used.  Optionally specify a
    /// `basicAllocator` used to supply memory.  If `basicAllocator` is not
    /// supplied, a default-constructed object of the (template parameter)
    /// type `ALLOCATOR` is used.  If the type `ALLOCATOR` is
    /// `bsl::allocator` and `basicAllocator` is not supplied, the currently
    /// installed default allocator is used to supply memory.  This method
    /// requires that the (template parameter) type `KEY` be
    /// `copy-constructible` (see {Requirements on `KEY`}).  Note that a
    /// `bslma::Allocator *` can be supplied for `basicAllocator` if the
    /// type `ALLOCATOR` is `bsl::allocator` (the default).
    template <class = bsl::enable_if_t<bsl::IsStdAllocator<ALLOCATOR>::value>>
# endif
    unordered_set(std::initializer_list<KEY> values,
                  const ALLOCATOR&           basicAllocator);
#endif

    /// Create an unordered set, and insert each `value_type` object in the
    /// specified `range`, ignoring those keys having a value equivalent to
    /// that which appears earlier in the `range`.  Optionally specify an
    /// `initialNumBuckets` indicating the initial size of the array of
    /// buckets of this container.  If `initialNumBuckets` is not supplied,
    /// an implementation-defined value is used.  Optionally specify a
    /// `hashFunction` used to generate the hash values for each key value
    /// contained in this set.  If `hashFunction` is not supplied, a
    /// default-constructed object of the (template parameter) type `HASH`
    /// is used.  Optionally specify a key-equality functor `keyEqual` used
    /// to determine whether two keys have the same value.  If `keyEqual` is
    /// not supplied, a default-constructed object of the (template
    /// parameter) type `EQUAL` is used.  Optionally specify a
    /// `basicAllocator` used to supply memory.  If `basicAllocator` is not
    /// supplied, a default-constructed object of the (template parameter)
    /// type `ALLOCATOR` is used.  If the type `ALLOCATOR` is
    /// `bsl::allocator` (the default), then `basicAllocator`, if supplied,
    /// shall be convertible to `bslma::Allocator *`.  If the type
    /// `ALLOCATOR` is `bsl::allocator` and `basicAllocator` is not
    /// supplied, the currently installed default allocator is used.  This
    /// operation has `O[N]` complexity, where `N` is the number of elements
    /// in `range`.  Note that `RANGE` must meet the requirements of an
    /// input range and the values from `range` must have a type matching or
    /// convertible to `value_type`.
    template <class RANGE>
    BSLSTL_UNORDEREDSET_REQUIRES_CONTAINER_COMPATIBLE_RANGE(RANGE, value_type)
    unordered_set(
         bsl::from_range_t                        ,
         BSLS_COMPILERFEATURES_FORWARD_REF(RANGE) range,
         size_type                                initialNumBuckets = 0,
         const HASH&                              hashFunction = HASH(),
         const EQUAL&                             keyEqual = EQUAL(),
         const ALLOCATOR&                         basicAllocator = ALLOCATOR())
    : d_impl(hashFunction,
                 keyEqual,
                 initialNumBuckets,
                 1.0f,
                 basicAllocator)
    {
        // Defined inline for Windows.

#if defined(BSLS_LIBRARYFEATURES_HAS_CPP20_CONCEPTS) \
 && defined(BSLS_LIBRARYFEATURES_HAS_CPP20_RANGES)
        if constexpr (ranges::sized_range<RANGE>) {
        constructFromRange(bsl::ranges::begin(range),
                   bsl::ranges::end  (range),
                   bsl::ranges::size (range));
        } else // ...
#endif
        {
        constructFromRange(bsl::ranges::begin(range),
                   bsl::ranges::end  (range));
        }
    }

    template <class RANGE>
    BSLSTL_UNORDEREDSET_REQUIRES_CONTAINER_COMPATIBLE_RANGE(RANGE, value_type)
    unordered_set(bsl::from_range_t                        ,
                  BSLS_COMPILERFEATURES_FORWARD_REF(RANGE) range,
                  size_type                                initialNumBuckets,
                  const HASH&                              hashFunction,
                  const ALLOCATOR&                         basicAllocator)
    : d_impl(hashFunction, EQUAL(), initialNumBuckets, 1.0f, basicAllocator)
    {
        // Defined inline for Windows.

        unordered_set other(bsl::from_range,
                            range,
                            initialNumBuckets,
                            hashFunction,
                            EQUAL(),
                            basicAllocator);
        this->swap(other);
    }

    template <class RANGE>
    BSLSTL_UNORDEREDSET_REQUIRES_CONTAINER_COMPATIBLE_RANGE(RANGE, value_type)
    unordered_set(bsl::from_range_t                        ,
                  BSLS_COMPILERFEATURES_FORWARD_REF(RANGE) range,
                  size_type                                initialNumBuckets,
                  const ALLOCATOR&                         basicAllocator)
    : d_impl(HASH(), EQUAL(), initialNumBuckets, 1.0f, basicAllocator)
    {
        // Defined inline for Windows.

        unordered_set other(bsl::from_range,
                            range,
                            initialNumBuckets,
                            HASH(),
                            EQUAL(),
                            basicAllocator);
        this->swap(other);
    }

    template <class RANGE>
    BSLSTL_UNORDEREDSET_REQUIRES_CONTAINER_COMPATIBLE_RANGE(RANGE, value_type)
    unordered_set(bsl::from_range_t                        ,
                  BSLS_COMPILERFEATURES_FORWARD_REF(RANGE) range,
                  const ALLOCATOR&                         basicAllocator)
    : d_impl(HASH(), EQUAL(), 0, 1.0f, basicAllocator)
    {
        // Defined inline for Windows.

        unordered_set other(bsl::from_range,
                            range,
                            0,
                            HASH(),
                            EQUAL(),
                            basicAllocator);
        this->swap(other);
    }

    /// Destroy this object.
    ~unordered_set();

    // MANIPULATORS

    /// Assign to this object the value, hash function, and equality
    /// comparator of the specified `rhs` object, propagate to this object
    /// the allocator of `rhs` if the `ALLOCATOR` type has trait
    /// `propagate_on_container_copy_assignment`, and return a reference
    /// providing modifiable access to this object.  If an exception is
    /// thrown, `*this` is left in a valid but unspecified state.  This
    /// method requires that the (template parameter) type `KEY` be
    /// `copy-assignable` and 'copy-insertable" into this set (see
    /// {Requirements on `KEY`}).
    unordered_set& operator=(const unordered_set& rhs);

    /// Assign to this object the value, hash function, and equality
    /// comparator of the specified `rhs` object, propagate to this object
    /// the allocator of `rhs` if the `ALLOCATOR` type has trait
    /// `propagate_on_container_move_assignment`, and return a reference
    /// providing modifiable access to this object.  The contents of `rhs`
    /// are moved (in constant time) to this set if
    /// `get_allocator() == rhs.get_allocator()` (after accounting for the
    /// aforementioned trait); otherwise, all elements in this set are
    /// either destroyed or move-assigned to and each additional element in
    /// `rhs` is move-inserted into this set.  `rhs` is left in a valid but
    /// unspecified state, and if an exception is thrown, `*this` is left in
    /// a valid but unspecified state.  This method requires that the
    /// (template parameter) type `KEY` be both `move-assignable` and
    /// `move-insertable` into this set (see {Requirements on `KEY`}).
    unordered_set&
    operator=(BloombergLP::bslmf::MovableRef<unordered_set> rhs)
                            BSLS_KEYWORD_NOEXCEPT_SPECIFICATION(
                                AllocatorTraits::is_always_equal::value
                             && std::is_nothrow_move_assignable<HASH>::value
                             && std::is_nothrow_move_assignable<EQUAL>::value);

#if defined(BSLS_COMPILERFEATURES_SUPPORT_GENERALIZED_INITIALIZERS)
    /// Assign to this object the value resulting from first clearing this
    /// unordered set and then inserting each `value_type` object in the
    /// specified `values` initializer list, ignoring those keys having a
    /// value equivalent to that which appears earlier in the list; return a
    /// reference providing modifiable access to this object.  This method
    /// requires that the (template parameter) type `KEY` type be
    /// `copy-insertable` into this set (see {Requirements on `KEY`}).
    unordered_set& operator=(std::initializer_list<KEY> values);
#endif

    /// Return an iterator providing modifiable access to the first
    /// `value_type` object (in the sequence of `value_type` objects)
    /// maintained by this set, or the `end` iterator if this set is empty.
    iterator begin() BSLS_KEYWORD_NOEXCEPT;

    /// Return an iterator providing modifiable access to the past-the-end
    /// element in the sequence of `value_type` objects maintained by this
    /// unordered set.
    iterator end() BSLS_KEYWORD_NOEXCEPT;

    /// Return a local iterator providing modifiable access to the first
    /// `value_type` object in the sequence of `value_type` objects of the
    /// bucket having the specified `index`, in the array of buckets
    /// maintained by this set, or the `end(index)` otherwise.
    local_iterator begin(size_type index);

    /// Return a local iterator providing modifiable access to the
    /// past-the-end element in the sequence of `value_type` objects of the
    /// bucket having the specified `index`s, in the array of buckets
    /// maintained by this set.
    local_iterator end(size_type index);

    /// Insert the specified `value` into this set if a key equivalent to
    /// `value` does not already exist in this set; otherwise, if a key
    /// equivalent to `value` already exists in this set, this method has no
    /// effect.  Return a pair whose `first` member is an iterator referring
    /// to the (possibly newly inserted) `value_type` object in this set
    /// that is equivalent to `value`, and whose `second` member is `true`
    /// if a new value was inserted, and `false` if the key was already
    /// present.  This method requires that the (template parameter) type
    /// `KEY` be `copy-insertable` (see {Requirements on `KEY`}).
    pair<iterator, bool> insert(const value_type& value);

    /// Insert the specified `value` into this set if a key equivalent to
    /// `value` does not already exist in this set; otherwise, if a key
    /// equivalent to `value` already exists in this set, this method has no
    /// effect.  `value` is left in a valid but unspecified state.  Return a
    /// pair whose `first` member is an iterator referring to the (possibly
    /// newly inserted) `value_type` object in this set that is equivalent
    /// to `value`, and whose `second` member is `true` if a new value was
    /// inserted, and `false` if the key was already present.  This method
    /// requires that the (template parameter) type `KEY` be
    /// `move-insertable` into this set (see {Requirements on `KEY`}).
    pair<iterator, bool> insert(
                             BloombergLP::bslmf::MovableRef<value_type> value);

// {{{ BEGIN GENERATED CODE
// The generated code below is a workaround for the absence of perfect
// forwarding in some compilers.
    template <class LOOKUP_KEY>
    typename enable_if<
           BloombergLP::bslmf::IsTransparentPredicate<HASH, LOOKUP_KEY>::value
        && BloombergLP::bslmf::IsTransparentPredicate<EQUAL,LOOKUP_KEY>::value,
                      pair<iterator, bool> >::type
    insert(BSLS_COMPILERFEATURES_FORWARD_REF(LOOKUP_KEY) value)
    {
        typedef bsl::pair<iterator, bool> ResultType;
        bool isInsertedFlag = false;
        HashTableLink *result =
                d_impl.insertIfMissingTransparent(
                             &isInsertedFlag,
                             BSLS_COMPILERFEATURES_FORWARD(LOOKUP_KEY, value));
        return ResultType(iterator(result), isInsertedFlag);
    }
// }}} END GENERATED CODE

    /// Insert the specified `value` into this set if a key equivalent to
    /// `value` does not already exist in this set; otherwise, if a key
    /// equivalent to `value` already exists in this set, this method has no
    /// effect.  Return an iterator referring to the (possibly newly
    /// inserted) `value_type` object in this set that is equivalent to
    /// `value`.  The average and worst case complexity of this operation is
    /// not affected by the specified `hint`.  This method requires that the
    /// (template parameter) type `KEY` be `copy-constructible` into this
    /// set (see {Requirements on `KEY`}).  The behavior is undefined unless
    /// `hint` is an iterator in the range `[begin() .. end()]` (both
    /// endpoints included).  Note that `hint` is ignored (other than
    /// possibly asserting its validity in some build modes).
    iterator insert(const_iterator hint, const value_type& value);

    /// Insert the specified `value` into this set if a key equivalent to
    /// `value` does not already exist in this set; otherwise, if a key
    /// equivalent to `value` already exists in this set, this method has no
    /// effect.  `value` is left in a valid but unspecified state.  Return
    /// an iterator referring to the (possibly newly inserted) `value_type`
    /// object in this set that is equivalent to `value`.  The average and
    /// worst case complexity of this operation is not affected by the
    /// specified `hint`.  This method requires that the (template
    /// parameter) type `KEY` be `move-insertable` (see {Requirements on
    /// `KEY`}) into this set.  The behavior is undefined unless `hint` is
    /// an iterator in the range `[begin() .. end()]` (both endpoints
    /// included).  Note that `hint` is ignored (other than possibly
    /// asserting its validity in some build modes).
    iterator insert(const_iterator                             hint,
                    BloombergLP::bslmf::MovableRef<value_type> value);

// {{{ BEGIN GENERATED CODE
// The generated code below is a workaround for the absence of perfect
// forwarding in some compilers.
    template <class LOOKUP_KEY>
    typename enable_if<
           BloombergLP::bslmf::IsTransparentPredicate<HASH, LOOKUP_KEY>::value
        && BloombergLP::bslmf::IsTransparentPredicate<EQUAL,LOOKUP_KEY>::value
        && !bsl::is_convertible<BSLS_COMPILERFEATURES_FORWARD_REF(LOOKUP_KEY),
                                iterator>::value
        && !bsl::is_convertible<BSLS_COMPILERFEATURES_FORWARD_REF(LOOKUP_KEY),
                                const_iterator>::value
         , iterator>::type
    insert(const_iterator, BSLS_COMPILERFEATURES_FORWARD_REF(LOOKUP_KEY) value)
    {
        return this->insert(
                       BSLS_COMPILERFEATURES_FORWARD(LOOKUP_KEY, value)).first;
    }
// }}} END GENERATED CODE

    /// Insert into this set the value of each `value_type` object in the
    /// range starting at the specified `first` iterator and ending
    /// immediately before the specified `last` iterator, if a  key
    /// equivalent to the object is not already contained in this set.  The
    /// (template parameter) type `INPUT_ITERATOR` shall meet the
    /// requirements of an input iterator defined in the C++11 standard
    /// [24.2.3] providing access to values of a type convertible to
    /// `value_type`, and `value_type` must be `emplace-constructible` from
    /// `*i` into this set, where `i` is a dereferenceable iterator in the
    /// range `[first .. last)` (see {Requirements on `KEY`}).  The behavior
    /// is undefined unless `first` and `last` refer to a sequence of valid
    /// values where `first` is at a position at or before `last`.
    template <class INPUT_ITERATOR>
    void insert(INPUT_ITERATOR first, INPUT_ITERATOR last);

#if defined(BSLS_COMPILERFEATURES_SUPPORT_GENERALIZED_INITIALIZERS)
    /// Insert into this set the value of each `value_type` object in the
    /// specified `values` initializer list if a key equivalent to the
    /// object is not already contained in this set.  This method requires
    /// that the (template parameter) type `KEY` be `copy-insertable` (see
    /// {Requirements on `KEY`}).
    void insert(std::initializer_list<KEY> values);
#endif

    /// Insert into this set the value of each `value_type` object in the
    /// specified `range` if a key equivalent to the object is not already
    /// contained in this set.  The (template parameter) type `RANGE` must
    /// meet the requirements the C++20 standard [ranges] providing access
    /// to values of a type convertible to `value_type`, and `value_type`
    /// must be `emplace-constructible` from `*i` into this set, where `i`
    /// is a dereferenceable iterator obtained from `range` (see
    /// {Requirements on `KEY`}).  The behavior is undefined if `range`
    /// overlaps this set.
    template <class RANGE>
    BSLSTL_UNORDEREDSET_REQUIRES_CONTAINER_COMPATIBLE_RANGE(RANGE, value_type)
    void insert_range(BSLS_COMPILERFEATURES_FORWARD_REF(RANGE) range)
    {
        // Defined inline for Windows.

#if defined(BSLS_LIBRARYFEATURES_HAS_CPP20_CONCEPTS) \
&& defined(BSLS_LIBRARYFEATURES_HAS_CPP20_RANGES)
        if constexpr (ranges::sized_range<RANGE>) {
            insertFromRange(bsl::ranges::begin(range),
                            bsl::ranges::end  (range),
                            bsl::ranges::size (range));
        } else // ...
#endif
        {
            insertFromRange(bsl::ranges::begin(range),
                            bsl::ranges::end  (range));
        }
    }

#if BSLS_COMPILERFEATURES_SIMULATE_VARIADIC_TEMPLATES
// {{{ BEGIN GENERATED CODE
// Command line: sim_cpp11_features.pl bslstl_unorderedset.h
#ifndef BSLSTL_UNORDEREDSET_VARIADIC_LIMIT
#define BSLSTL_UNORDEREDSET_VARIADIC_LIMIT 10
#endif
#ifndef BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_C
#define BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_C BSLSTL_UNORDEREDSET_VARIADIC_LIMIT
#endif
#if BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_C >= 0
    pair<iterator, bool> emplace(
                         );
#endif  // BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_C >= 0

#if BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_C >= 1
    template <class Args_01>
    pair<iterator, bool> emplace(
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_01) arguments_01);
#endif  // BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_C >= 1

#if BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_C >= 2
    template <class Args_01,
              class Args_02>
    pair<iterator, bool> emplace(
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_01) arguments_01,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_02) arguments_02);
#endif  // BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_C >= 2

#if BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_C >= 3
    template <class Args_01,
              class Args_02,
              class Args_03>
    pair<iterator, bool> emplace(
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_01) arguments_01,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_02) arguments_02,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_03) arguments_03);
#endif  // BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_C >= 3

#if BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_C >= 4
    template <class Args_01,
              class Args_02,
              class Args_03,
              class Args_04>
    pair<iterator, bool> emplace(
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_01) arguments_01,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_02) arguments_02,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_03) arguments_03,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_04) arguments_04);
#endif  // BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_C >= 4

#if BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_C >= 5
    template <class Args_01,
              class Args_02,
              class Args_03,
              class Args_04,
              class Args_05>
    pair<iterator, bool> emplace(
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_01) arguments_01,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_02) arguments_02,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_03) arguments_03,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_04) arguments_04,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_05) arguments_05);
#endif  // BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_C >= 5

#if BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_C >= 6
    template <class Args_01,
              class Args_02,
              class Args_03,
              class Args_04,
              class Args_05,
              class Args_06>
    pair<iterator, bool> emplace(
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_01) arguments_01,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_02) arguments_02,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_03) arguments_03,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_04) arguments_04,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_05) arguments_05,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_06) arguments_06);
#endif  // BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_C >= 6

#if BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_C >= 7
    template <class Args_01,
              class Args_02,
              class Args_03,
              class Args_04,
              class Args_05,
              class Args_06,
              class Args_07>
    pair<iterator, bool> emplace(
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_01) arguments_01,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_02) arguments_02,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_03) arguments_03,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_04) arguments_04,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_05) arguments_05,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_06) arguments_06,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_07) arguments_07);
#endif  // BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_C >= 7

#if BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_C >= 8
    template <class Args_01,
              class Args_02,
              class Args_03,
              class Args_04,
              class Args_05,
              class Args_06,
              class Args_07,
              class Args_08>
    pair<iterator, bool> emplace(
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_01) arguments_01,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_02) arguments_02,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_03) arguments_03,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_04) arguments_04,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_05) arguments_05,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_06) arguments_06,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_07) arguments_07,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_08) arguments_08);
#endif  // BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_C >= 8

#if BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_C >= 9
    template <class Args_01,
              class Args_02,
              class Args_03,
              class Args_04,
              class Args_05,
              class Args_06,
              class Args_07,
              class Args_08,
              class Args_09>
    pair<iterator, bool> emplace(
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_01) arguments_01,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_02) arguments_02,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_03) arguments_03,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_04) arguments_04,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_05) arguments_05,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_06) arguments_06,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_07) arguments_07,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_08) arguments_08,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_09) arguments_09);
#endif  // BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_C >= 9

#if BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_C >= 10
    template <class Args_01,
              class Args_02,
              class Args_03,
              class Args_04,
              class Args_05,
              class Args_06,
              class Args_07,
              class Args_08,
              class Args_09,
              class Args_10>
    pair<iterator, bool> emplace(
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_01) arguments_01,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_02) arguments_02,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_03) arguments_03,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_04) arguments_04,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_05) arguments_05,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_06) arguments_06,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_07) arguments_07,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_08) arguments_08,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_09) arguments_09,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_10) arguments_10);
#endif  // BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_C >= 10


#if BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_C >= 0
    iterator emplace_hint(const_iterator hint);
#endif  // BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_C >= 0

#if BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_C >= 1
    template <class Args_01>
    iterator emplace_hint(const_iterator hint,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_01) arguments_01);
#endif  // BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_C >= 1

#if BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_C >= 2
    template <class Args_01,
              class Args_02>
    iterator emplace_hint(const_iterator hint,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_01) arguments_01,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_02) arguments_02);
#endif  // BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_C >= 2

#if BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_C >= 3
    template <class Args_01,
              class Args_02,
              class Args_03>
    iterator emplace_hint(const_iterator hint,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_01) arguments_01,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_02) arguments_02,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_03) arguments_03);
#endif  // BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_C >= 3

#if BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_C >= 4
    template <class Args_01,
              class Args_02,
              class Args_03,
              class Args_04>
    iterator emplace_hint(const_iterator hint,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_01) arguments_01,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_02) arguments_02,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_03) arguments_03,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_04) arguments_04);
#endif  // BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_C >= 4

#if BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_C >= 5
    template <class Args_01,
              class Args_02,
              class Args_03,
              class Args_04,
              class Args_05>
    iterator emplace_hint(const_iterator hint,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_01) arguments_01,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_02) arguments_02,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_03) arguments_03,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_04) arguments_04,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_05) arguments_05);
#endif  // BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_C >= 5

#if BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_C >= 6
    template <class Args_01,
              class Args_02,
              class Args_03,
              class Args_04,
              class Args_05,
              class Args_06>
    iterator emplace_hint(const_iterator hint,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_01) arguments_01,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_02) arguments_02,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_03) arguments_03,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_04) arguments_04,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_05) arguments_05,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_06) arguments_06);
#endif  // BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_C >= 6

#if BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_C >= 7
    template <class Args_01,
              class Args_02,
              class Args_03,
              class Args_04,
              class Args_05,
              class Args_06,
              class Args_07>
    iterator emplace_hint(const_iterator hint,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_01) arguments_01,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_02) arguments_02,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_03) arguments_03,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_04) arguments_04,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_05) arguments_05,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_06) arguments_06,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_07) arguments_07);
#endif  // BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_C >= 7

#if BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_C >= 8
    template <class Args_01,
              class Args_02,
              class Args_03,
              class Args_04,
              class Args_05,
              class Args_06,
              class Args_07,
              class Args_08>
    iterator emplace_hint(const_iterator hint,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_01) arguments_01,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_02) arguments_02,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_03) arguments_03,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_04) arguments_04,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_05) arguments_05,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_06) arguments_06,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_07) arguments_07,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_08) arguments_08);
#endif  // BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_C >= 8

#if BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_C >= 9
    template <class Args_01,
              class Args_02,
              class Args_03,
              class Args_04,
              class Args_05,
              class Args_06,
              class Args_07,
              class Args_08,
              class Args_09>
    iterator emplace_hint(const_iterator hint,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_01) arguments_01,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_02) arguments_02,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_03) arguments_03,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_04) arguments_04,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_05) arguments_05,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_06) arguments_06,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_07) arguments_07,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_08) arguments_08,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_09) arguments_09);
#endif  // BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_C >= 9

#if BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_C >= 10
    template <class Args_01,
              class Args_02,
              class Args_03,
              class Args_04,
              class Args_05,
              class Args_06,
              class Args_07,
              class Args_08,
              class Args_09,
              class Args_10>
    iterator emplace_hint(const_iterator hint,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_01) arguments_01,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_02) arguments_02,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_03) arguments_03,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_04) arguments_04,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_05) arguments_05,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_06) arguments_06,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_07) arguments_07,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_08) arguments_08,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_09) arguments_09,
                      BSLS_COMPILERFEATURES_FORWARD_REF(Args_10) arguments_10);
#endif  // BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_C >= 10

#else
// The generated code below is a workaround for the absence of perfect
// forwarding in some compilers.
    template <class... Args>
    pair<iterator, bool> emplace(
                         BSLS_COMPILERFEATURES_FORWARD_REF(Args)... arguments);

    template <class... Args>
    iterator emplace_hint(const_iterator hint,
                         BSLS_COMPILERFEATURES_FORWARD_REF(Args)... arguments);

// }}} END GENERATED CODE
#endif

    /// Remove from this unordered set the `value_type` object at the
    /// specified `position`, and return an iterator referring to the
    /// element immediately following the removed element, or to the
    /// past-the-end position if the removed element was the last element in
    /// the sequence of elements maintained by this set.  This method
    /// invalidates only iterators and references to the removed element and
    /// previously saved values of the `end()` iterator, and preserves the
    /// relative order of the elements not removed.  The behavior is
    /// undefined unless `position` refers to a `value_type` object in this
    /// unordered set.
    iterator erase(const_iterator position);

    /// Remove from this set the `value_type` object that is equivalent to
    /// the specified `key`, if such an entry exists, and return 1;
    /// otherwise, if there is no `value_type` object that is equivalent to
    /// `key`, return 0 with no other effect.  This method invalidates only
    /// iterators and references to the removed element and previously saved
    /// values of the `end()` iterator, and preserves the relative order of
    /// the elements not removed.
    size_type erase(const key_type& key);
    template <class t_KEY>
    typename enable_if<
        BloombergLP::bslmf::IsTransparentPredicate<HASH, t_KEY>::value &&
        BloombergLP::bslmf::IsTransparentPredicate<EQUAL,t_KEY>::value &&
        !is_convertible<BSLS_COMPILERFEATURES_FORWARD_REF(t_KEY),
                        iterator>::value &&
        !is_convertible<BSLS_COMPILERFEATURES_FORWARD_REF(t_KEY),
                        const_iterator>::value,
    size_type>::type erase(BSLS_COMPILERFEATURES_FORWARD_REF(t_KEY) key)
    {
        // Implemented inline due to Sun CC compilation error.
        iterator it = this->find(key);
        if (it == end()) {
            return 0;                                                 // RETURN
        }
        erase(it);
        return 1;
    }

    /// Remove from this set the `value_type` objects starting at the
    /// specified `first` position up to, but including the specified `last`
    /// position, and return `last`.  This method invalidates only iterators
    /// and references to the removed element and previously saved values of
    /// the `end()` iterator, and preserves the relative order of the
    /// elements not removed.  The behavior is undefined unless `first` and
    /// `last` either refer to elements in this set or are the `end`
    /// iterator, and the `first` position is at or before the `last`
    /// position in the sequence provided by this container.
    iterator erase(const_iterator first, const_iterator last);

    /// Exchange the value, hasher, key-equality functor, and
    /// `max_load_factor` of this object with those of the specified `other`
    /// object; also exchange the allocator of this object with that of
    /// `other` if the (template parameter) type `ALLOCATOR` has the
    /// `propagate_on_container_swap` trait, and do not modify either
    /// allocator otherwise.  This method provides the no-throw
    /// exception-safety guarantee if and only if both the (template
    /// parameter) types `HASH` and `EQUAL` provide no-throw swap
    /// operations; if an exception is thrown, both objects are left in
    /// valid but unspecified states.  This operation guarantees `O[1]`
    /// complexity.  The behavior is undefined unless either this object was
    /// created with the same allocator as `other` or `ALLOCATOR` has the
    /// `propagate_on_container_swap` trait.
    void swap(unordered_set& other) BSLS_KEYWORD_NOEXCEPT_SPECIFICATION(
                                      AllocatorTraits::is_always_equal::value
                                  &&  bsl::is_nothrow_swappable<HASH>::value
                                  &&  bsl::is_nothrow_swappable<EQUAL>::value);

    /// Remove all entries from this unordered set.  Note that the set is
    /// empty after this call, but allocated memory may be retained for
    /// future use.
    void clear() BSLS_KEYWORD_NOEXCEPT;

    /// Return an iterator providing modifiable access to the `value_type`
    /// object in this unordered set that is equivalent to the specified
    /// `key`, if such an entry exists, and the past-the-end (`end`)
    /// iterator otherwise.  The behavior is undefined unless `key` is
    /// equivalent to at most one element in this unordered set.
    ///
    /// Note: implemented inline due to Sun CC compilation error.
    template <class LOOKUP_KEY>
    typename enable_if<
           BloombergLP::bslmf::IsTransparentPredicate<HASH, LOOKUP_KEY>::value
        && BloombergLP::bslmf::IsTransparentPredicate<EQUAL,LOOKUP_KEY>::value,
                      iterator>::type
    find(const LOOKUP_KEY& key)
        {
            return iterator(d_impl.find(key));
        }

    /// Return an iterator providing modifiable access to the `value_type`
    /// object in this unordered set that is equivalent to the specified
    /// `key`, if such an entry exists, and the past-the-end (`end`)
    /// iterator otherwise.
    iterator find(const key_type& key);

    /// Return a pair of iterators providing modifiable access to the
    /// sequence of `value_type` objects in this unordered set that are
    /// equivalent to the specified `key`, where the first iterator is
    /// positioned at the start of the sequence, and the second is
    /// positioned one past the end of the sequence.  If this unordered set
    /// contains no `value_type` objects equivalent to `key`, then the two
    /// returned iterators will have the same value.  The behavior is
    /// undefined unless `key` is equivalent to at most one element in this
    /// unordered set.  Note that since an unordered set maintains unique
    /// keys, the range will contain at most one element.
    ///
    /// Note: implemented inline due to Sun CC compilation error.
    template <class LOOKUP_KEY>
    typename enable_if<
           BloombergLP::bslmf::IsTransparentPredicate<HASH, LOOKUP_KEY>::value
        && BloombergLP::bslmf::IsTransparentPredicate<EQUAL,LOOKUP_KEY>::value,
                      pair<iterator, iterator> >::type
    equal_range(const LOOKUP_KEY& key)
        {
            typedef bsl::pair<iterator, iterator> ResultType;

            HashTableLink *first = d_impl.find(key);
            return first
                   ? ResultType(iterator(first), iterator(first->nextLink()))
                   : ResultType(iterator(0),     iterator(0));
        }

    /// Return a pair of iterators providing modifiable access to the
    /// sequence of `value_type` objects in this unordered set that are
    /// equivalent to the specified `key`, where the first iterator is
    /// positioned at the start of the sequence, and the second is
    /// positioned one past the end of the sequence.  If this unordered set
    /// contains no `value_type` objects equivalent to `key`, then the two
    /// returned iterators will have the same value.  Note that since an
    /// unordered set maintains unique keys, the range will contain at most
    /// one element.
    pair<iterator, iterator> equal_range(const key_type& key);

    /// Set the maximum load factor of this container to the specified
    /// `newLoadFactor`.
    void max_load_factor(float newLoadFactor);

    /// Change the size of the array of buckets maintained by this container
    /// to the specified `numBuckets`, and redistribute all the contained
    /// elements into the new sequence of buckets, according to their hash
    /// values.  Note that this operation has no effect if rehashing the
    /// elements into `numBuckets` would cause this set to exceed its
    /// `max_load_factor`.
    void rehash(size_type numBuckets);

    /// Increase the number of buckets of this set to a quantity such that
    /// the ratio between the specified `numElements` and this quantity does
    /// not exceed `max_load_factor`.  Note that this guarantees that, after
    /// the reserve, elements can be inserted to grow the container to
    /// `size() == numElements` without rehashing.  Also note that memory
    /// allocations may still occur when growing the container to
    /// `size() == numElements`.  Also note that this operation has no
    /// effect if `numElements <= size()`.
    void reserve(size_type numElements);

  private:
    // PRIVATE MANIPULATORS

    /// Insert the values between the specified `first` and `last` into an
    /// initially empty set.
    template <class INPUT_ITERATOR, class SENTINEL>
    void constructFromRange(INPUT_ITERATOR first, SENTINEL last);

#if defined(BSLS_LIBRARYFEATURES_HAS_CPP20_CONCEPTS) \
 && defined(BSLS_LIBRARYFEATURES_HAS_CPP20_RANGES)

    /// Insert the values between the specified `first` and `last` into an
    /// initially empty set.  The specified `numElements` is used to improve
    /// performance.  The behavior is undefined if the iterators support
    /// the calculation of distance and `numElements` is not the distance
    /// from `first` to `last`.
    template <class INPUT_ITERATOR, class SENTINEL>
    void constructFromRange(INPUT_ITERATOR first,
                            SENTINEL       last,
                            size_t         numElements);
#endif

    /// Insert the values between the specified `first` and `last` into this
    /// set.
    template <class INPUT_ITERATOR, class SENTINEL>
    void insertFromRange(INPUT_ITERATOR first, SENTINEL last);

#if defined(BSLS_LIBRARYFEATURES_HAS_CPP20_CONCEPTS) \
 && defined(BSLS_LIBRARYFEATURES_HAS_CPP20_RANGES)

    /// Insert the values between the specified `first` and `last` into this
    /// set.  The specified `numElements` is used to improve performance.
    /// The behavior is undefined if the iterators support the calculation of
    /// distance and `numElements` is not the distance from `first` to `last`.
    template <class INPUT_ITERATOR, class SENTINEL>
    void insertFromRange(INPUT_ITERATOR first,
                         SENTINEL       last,
                         size_t         numElements);
#endif

  public:
    // ACCESSORS

    /// Return (a copy of) the allocator used for memory allocation by this
    /// unordered set.
    ALLOCATOR get_allocator() const BSLS_KEYWORD_NOEXCEPT;

    /// Return an iterator providing non-modifiable access to the first
    /// `value_type` object in the sequence of `value_type` objects
    /// maintained by this set, or the `end` iterator if this set is empty.
    const_iterator begin() const BSLS_KEYWORD_NOEXCEPT;

    /// Return an iterator providing non-modifiable access to the
    /// past-the-end element in the sequence of `value_type` objects
    /// maintained by this set.
    const_iterator end() const BSLS_KEYWORD_NOEXCEPT;

    /// Return an iterator providing non-modifiable access to the first
    /// `value_type` object in the sequence of `value_type` objects
    /// maintained by this set, or the `cend` iterator if this set is empty.
    const_iterator cbegin() const BSLS_KEYWORD_NOEXCEPT;

    /// Return an iterator providing non-modifiable access to the
    /// past-the-end element (in the sequence of `value_type` objects)
    /// maintained by this set.
    const_iterator cend() const BSLS_KEYWORD_NOEXCEPT;

    /// Return `true` if this unordered set contains an element whose key is
    /// equivalent to the specified `key`.
    bool contains(const key_type &key) const;

    /// Return `true` if this unordered set contains an element whose key is
    /// equivalent to the specified `key`.
    ///
    /// Note: implemented inline due to Sun CC compilation error.
    template <class LOOKUP_KEY>
    typename enable_if<
        BloombergLP::bslmf::IsTransparentPredicate<HASH, LOOKUP_KEY>::value &&
            BloombergLP::bslmf::IsTransparentPredicate<EQUAL,
                                                       LOOKUP_KEY>::value,
        bool>::type
    contains(const LOOKUP_KEY& key) const
    {
        return find(key) != end();
    }

    /// Return `true` if this set contains no elements, and `false`
    /// otherwise.
    bool empty() const BSLS_KEYWORD_NOEXCEPT;

    /// Return the number of elements in this set.
    size_type size() const BSLS_KEYWORD_NOEXCEPT;

    /// Return a theoretical upper bound on the largest number of elements
    /// that this set could possibly hold.  Note that there is no guarantee
    /// that the set can successfully grow to the returned size, or even
    /// close to that size without running out of resources.
    size_type max_size() const BSLS_KEYWORD_NOEXCEPT;

    /// Return (a copy of) the key-equality binary functor that returns
    /// `true` if the value of two `key_type` objects are equivalent, and
    /// `false` otherwise.
    EQUAL key_eq() const;

    /// Return (a copy of) the hash unary functor used by this set to
    /// generate a hash value (of type `size_t`) for a `key_type` object.
    HASH hash_function() const;

    /// Return an iterator providing non-modifiable access to the
    /// `value_type` object in this unordered set that is equivalent to the
    /// specified `key`, if such an entry exists, and the past-the-end
    /// (`end`) iterator otherwise.  The behavior is undefined unless `key`
    /// is equivalent to at most one element in this unordered set.
    ///
    /// Note: implemented inline due to Sun CC compilation error.
    template <class LOOKUP_KEY>
    typename enable_if<
           BloombergLP::bslmf::IsTransparentPredicate<HASH, LOOKUP_KEY>::value
        && BloombergLP::bslmf::IsTransparentPredicate<EQUAL,LOOKUP_KEY>::value,
                      const_iterator>::type
    find(const LOOKUP_KEY& key) const
        {
            return const_iterator(d_impl.find(key));
        }

    /// Return an iterator providing non-modifiable access to the
    /// `value_type` object in this unordered set that is equivalent to the
    /// specified `key`, if such an entry exists, and the past-the-end
    /// (`end`) iterator otherwise.
    const_iterator find(const key_type& key) const;

    /// Return the number of `value_type` objects within this unordered set
    /// that are equivalent to the specified `key`.  The behavior is
    /// undefined unless `key` is equivalent to at most one element in this
    /// unordered set.  Note that since an unordered set maintains unique
    /// keys, the returned value will be either 0 or 1.
    ///
    /// Note: implemented inline due to Sun CC compilation error.
    template <class LOOKUP_KEY>
    typename enable_if<
           BloombergLP::bslmf::IsTransparentPredicate<HASH, LOOKUP_KEY>::value
        && BloombergLP::bslmf::IsTransparentPredicate<EQUAL,LOOKUP_KEY>::value,
                      size_type>::type
    count(const LOOKUP_KEY& key) const
        {
            return d_impl.find(key) != 0;
        }

    /// Return the number of `value_type` objects within this unordered set
    /// that are equivalent to the specified `key`.  Note that since an
    /// unordered set maintains unique keys, the returned value will be
    /// either 0 or 1.
    size_type count(const key_type& key) const;

    /// Return a pair of iterators providing non-modifiable access to the
    /// sequence of `value_type` objects in this unordered set that are
    /// equivalent to the specified `key`, where the first iterator is
    /// positioned at the start of the sequence and the second iterator is
    /// positioned one past the end of the sequence.  If this unordered set
    /// contains no `value_type` objects equivalent to `key`, then the two
    /// returned iterators will have the same value.  The behavior is
    /// undefined unless `key` is equivalent to at most one element in this
    /// unordered set.  Note that since an unordered set maintains unique
    /// keys, the range will contain at most one element.
    ///
    /// Note: implemented inline due to Sun CC compilation error.
    template <class LOOKUP_KEY>
    typename enable_if<
           BloombergLP::bslmf::IsTransparentPredicate<HASH, LOOKUP_KEY>::value
        && BloombergLP::bslmf::IsTransparentPredicate<EQUAL,LOOKUP_KEY>::value,
                      pair<const_iterator, const_iterator> >::type
    equal_range(const LOOKUP_KEY& key) const
        {
            typedef bsl::pair<const_iterator, const_iterator> ResultType;

            HashTableLink *first = d_impl.find(key);
            return first
                 ? ResultType(iterator(first), iterator(first->nextLink()))
                 : ResultType(iterator(0),     iterator(0));
        }

    /// Return a pair of iterators providing non-modifiable access to the
    /// sequence of `value_type` objects in this unordered set that are
    /// equivalent to the specified `key`, where the first iterator is
    /// positioned at the start of the sequence and the second iterator is
    /// positioned one past the end of the sequence.  If this unordered set
    /// contains no `value_type` objects equivalent to `key`, then the two
    /// returned iterators will have the same value.  Note that since an
    /// unordered set maintains unique keys, the range will contain at most
    /// one element.
    pair<const_iterator, const_iterator> equal_range(
                                                    const key_type& key) const;

    /// Return the number of buckets in the array of buckets maintained by
    /// this set.
    size_type bucket_count() const BSLS_KEYWORD_NOEXCEPT;

    /// Return a theoretical upper bound on the largest number of buckets
    /// that this container could possibly manage.  Note that there is no
    /// guarantee that the set can successfully grow to the returned size,
    /// or even close to that size without running out of resources.
    size_type max_bucket_count() const BSLS_KEYWORD_NOEXCEPT;

    /// Return the number of elements contained in the bucket at the
    /// specified `index` in the array of buckets maintained by this
    /// container.
    size_type bucket_size(size_type index) const;

    /// Return the index of the bucket, in the array of buckets of this
    /// container, where a value equivalent to the specified `key` would be
    /// inserted.
    size_type bucket(const key_type& key) const;

    /// Return the index of the bucket, in the array of buckets of this
    /// container, where a value equivalent to the specified `key` would be
    /// inserted.
    ///
    /// Note: implemented inline due to Sun CC compilation error.
    template <class LOOKUP_KEY>
    typename enable_if<
           BloombergLP::bslmf::IsTransparentPredicate<HASH, LOOKUP_KEY>::value
        && BloombergLP::bslmf::IsTransparentPredicate<EQUAL,LOOKUP_KEY>::value,
                      size_type>::type
    bucket(const LOOKUP_KEY& key) const
    {
        return d_impl.bucketIndexForKey(key);
    }

    /// Return a local iterator providing non-modifiable access to the first
    /// `value_type` object (in the sequence of `value_type` objects) of the
    /// bucket having the specified `index` in the array of buckets
    /// maintained by this set, or the `end(index)` otherwise.
    const_local_iterator begin(size_type index) const;

    /// Return a local iterator providing non-modifiable access to the
    /// past-the-end element (in the sequence of `value_type` objects) of
    /// the bucket having the specified `index` in the array of buckets
    /// maintained by this set.
    const_local_iterator end(size_type index) const;

    /// Return a local iterator providing non-modifiable access to the first
    /// `value_type` object (in the sequence of `value_type` objects) of the
    /// bucket having the specified `index` in the array of buckets
    /// maintained by this set, or the `cend(index)` otherwise.
    const_local_iterator cbegin(size_type index) const;

    /// Return a local iterator providing non-modifiable access to the
    /// past-the-end element (in the sequence of `value_type` objects) of
    /// the bucket having the specified `index` in the array of buckets
    /// maintained by this set.
    const_local_iterator cend(size_type index) const;

    /// Return the current ratio between the `size` of this container and
    /// the number of buckets.  The `load_factor` is a measure of how full
    /// the container is, and a higher load factor leads to an increased
    /// number of collisions, thus resulting in a loss performance.
    float load_factor() const BSLS_KEYWORD_NOEXCEPT;

    /// Return the maximum load factor allowed for this container.  If an
    /// insert operation would cause `load_factor` to exceed the
    /// `max_load_factor`, that same insert operation will increase the
    /// number of buckets and rehash the elements of the container into
    /// those buckets the (see rehash).
    float max_load_factor() const BSLS_KEYWORD_NOEXCEPT;
};

#ifdef BSLS_COMPILERFEATURES_SUPPORT_CTAD
// CLASS TEMPLATE DEDUCTION GUIDES

/// Deduce the template parameter `KEY` from the `value_type` of the
/// iterators supplied to the constructor of `unordered_set`.  Deduce the
/// template parameters `HASH`, `EQUAL` and `ALLOCATOR` from the other
/// parameters passed to the constructor.  This deduction guide does not
/// participate unless: (1) the supplied `HASH` is invocable with a `KEY`,
/// (2) the supplied `EQUAL` is invocable with two `KEY`s, and (3) the
/// supplied allocator meets the requirements of a standard allocator.
template <
    class INPUT_ITERATOR,
    class KEY = BloombergLP::bslstl::IteratorUtil::IterVal_t<INPUT_ITERATOR>,
    class HASH = bsl::hash<KEY>,
    class EQUAL = bsl::equal_to<KEY>,
    class ALLOCATOR = bsl::allocator<KEY>,
    class = bsl::enable_if_t<std::is_invocable_v<HASH, const KEY&>>,
    class = bsl::enable_if_t<
                           std::is_invocable_v<EQUAL, const KEY&, const KEY&>>,
    class = bsl::enable_if_t< bsl::IsStdAllocator_v<ALLOCATOR>>
    >
unordered_set(INPUT_ITERATOR,
              INPUT_ITERATOR,
              typename bsl::allocator_traits<ALLOCATOR>::size_type = 0,
              HASH      = HASH(),
              EQUAL     = EQUAL(),
              ALLOCATOR = ALLOCATOR())
-> unordered_set<KEY, HASH, EQUAL, ALLOCATOR>;

/// Deduce the template parameter `KEY` from the `value_type` of the
/// iterators supplied to the constructor of `unordered_set`.  Deduce the
/// template parameters `HASH` and `EQUAL` from the other parameters passed
/// to the constructor.  This deduction guide does not participate unless
/// the supplied allocator is convertible to `bsl::allocator<KEY>`.
template <
    class INPUT_ITERATOR,
    class KEY = BloombergLP::bslstl::IteratorUtil::IterVal_t<INPUT_ITERATOR>,
    class HASH,
    class EQUAL,
    class ALLOC,
    class DEFAULT_ALLOCATOR = bsl::allocator<KEY>,
    class = bsl::enable_if_t<bsl::is_convertible_v<ALLOC *, DEFAULT_ALLOCATOR>>
    >
unordered_set(INPUT_ITERATOR,
              INPUT_ITERATOR,
              typename bsl::allocator_traits<DEFAULT_ALLOCATOR>::size_type,
              HASH,
              EQUAL,
              ALLOC *)
-> unordered_set<KEY, HASH, EQUAL>;

/// Deduce the template parameter `KEY` from the `value_type` of the
/// iterators supplied to the constructor of `unordered_set`.  Deduce the
/// template parameters `HASH` and `ALLOCATOR` from the other parameters
/// passed to the constructor.  This deduction guide does not participate
/// unless the supplied `HASH` is invocable with a `KEY`, and the supplied
/// allocator meets the requirements of a standard allocator.
template <
    class INPUT_ITERATOR,
    class KEY = BloombergLP::bslstl::IteratorUtil::IterVal_t<INPUT_ITERATOR>,
    class HASH,
    class ALLOCATOR,
    class = bsl::enable_if_t<std::is_invocable_v<HASH, const KEY &>>,
    class = bsl::enable_if_t< bsl::IsStdAllocator_v<ALLOCATOR>>
    >
unordered_set(INPUT_ITERATOR,
              INPUT_ITERATOR,
              typename bsl::allocator_traits<ALLOCATOR>::size_type,
              HASH,
              ALLOCATOR)
-> unordered_set<KEY, HASH, bsl::equal_to<KEY>, ALLOCATOR>;

/// Deduce the template parameter `KEY` from the `value_type` of the
/// iterators supplied to the constructor of `unordered_set`.  Deduce the
/// template parameter `HASH` from the other parameters passed to the
/// constructor.  This deduction guide does not participate unless the
/// supplied allocator is convertible to `bsl::allocator<KEY>`.
template <
    class INPUT_ITERATOR,
    class KEY = BloombergLP::bslstl::IteratorUtil::IterVal_t<INPUT_ITERATOR>,
    class HASH,
    class ALLOC,
    class DEFAULT_ALLOCATOR = bsl::allocator<KEY>,
    class = bsl::enable_if_t<bsl::is_convertible_v<ALLOC *, DEFAULT_ALLOCATOR>>
    >
unordered_set(INPUT_ITERATOR,
              INPUT_ITERATOR,
              typename bsl::allocator_traits<DEFAULT_ALLOCATOR>::size_type,
              HASH,
              ALLOC *)
-> unordered_set<KEY, HASH>;

/// Deduce the template parameter `KEY` from the `value_type` of the
/// iterators supplied to the constructor of `unordered_set`.   This
/// deduction guide does not participate unless the supplied allocator meets
/// the requirements of a standard allocator.
template <
    class INPUT_ITERATOR,
    class ALLOCATOR,
    class KEY = BloombergLP::bslstl::IteratorUtil::IterVal_t<INPUT_ITERATOR>,
    class = bsl::enable_if_t<bsl::IsStdAllocator_v<ALLOCATOR>>
    >
unordered_set(INPUT_ITERATOR,
              INPUT_ITERATOR,
              typename bsl::allocator_traits<ALLOCATOR>::size_type,
              ALLOCATOR)
-> unordered_set<KEY, bsl::hash<KEY>, bsl::equal_to<KEY>, ALLOCATOR>;

/// Deduce the template parameter `KEY` from the `value_type` of the
/// iterators supplied to the constructor of `unordered_set`.  This
/// deduction guide does not participate unless the supplied allocator is
/// convertible to `bsl::allocator<KEY>`.
template <
    class INPUT_ITERATOR,
    class KEY = BloombergLP::bslstl::IteratorUtil::IterVal_t<INPUT_ITERATOR>,
    class ALLOC,
    class DEFAULT_ALLOCATOR = bsl::allocator<KEY>,
    class = bsl::enable_if_t<bsl::is_convertible_v<ALLOC *, DEFAULT_ALLOCATOR>>
    >
unordered_set(INPUT_ITERATOR,
              INPUT_ITERATOR,
              typename bsl::allocator_traits<DEFAULT_ALLOCATOR>::size_type,
              ALLOC *)
-> unordered_set<KEY>;

/// Deduce the template parameter `KEY` from the `value_type` of the
/// iterators supplied to the constructor of `unordered_set`.   This
/// deduction guide does not participate unless the supplied allocator meets
/// the requirements of a standard allocator.
template <
    class INPUT_ITERATOR,
    class ALLOCATOR,
    class KEY = BloombergLP::bslstl::IteratorUtil::IterVal_t<INPUT_ITERATOR>,
    class = bsl::enable_if_t<bsl::IsStdAllocator_v<ALLOCATOR>>
    >
unordered_set(INPUT_ITERATOR, INPUT_ITERATOR, ALLOCATOR)
-> unordered_set<KEY, bsl::hash<KEY>, bsl::equal_to<KEY>, ALLOCATOR>;

/// Deduce the template parameter `KEY` from the `value_type` of the
/// iterators supplied to the constructor of `unordered_set`.  This
/// deduction guide does not participate unless the supplied allocator is
/// convertible to `bsl::allocator<KEY>`.
template <
    class INPUT_ITERATOR,
    class KEY = BloombergLP::bslstl::IteratorUtil::IterVal_t<INPUT_ITERATOR>,
    class ALLOC,
    class DEFAULT_ALLOCATOR = bsl::allocator<KEY>,
    class = bsl::enable_if_t<bsl::is_convertible_v<ALLOC *, DEFAULT_ALLOCATOR>>
    >
unordered_set(INPUT_ITERATOR, INPUT_ITERATOR, ALLOC *)
-> unordered_set<KEY>;

/// Deduce the template parameter `KEY` from the `value_type` of the
/// initializer_list supplied to the constructor of `unordered_set`.  Deduce
/// the template parameters `HASH`, EQUAL and `ALLOCATOR` from the other
/// parameters passed to the constructor.  This deduction guide does not
/// participate unless: (1) the supplied `HASH` is invocable with a `KEY`,
/// (2) the supplied `EQUAL` is invocable with two `KEY`s, and (3) the
/// supplied allocator meets the requirements of a standard allocator.
template <
    class KEY,
    class HASH = bsl::hash<KEY>,
    class EQUAL = bsl::equal_to<KEY>,
    class ALLOCATOR = bsl::allocator<KEY>,
    class = bsl::enable_if_t<std::is_invocable_v<HASH, const KEY&>>,
    class = bsl::enable_if_t<
                           std::is_invocable_v<EQUAL, const KEY&, const KEY&>>,
    class = bsl::enable_if_t< bsl::IsStdAllocator_v<ALLOCATOR>>
    >
unordered_set(std::initializer_list<KEY>,
              typename bsl::allocator_traits<ALLOCATOR>::size_type = 0,
              HASH      = HASH(),
              EQUAL     = EQUAL(),
              ALLOCATOR = ALLOCATOR())
-> unordered_set<KEY, HASH, EQUAL, ALLOCATOR>;

/// Deduce the template parameter `KEY` from the `value_type` of the
/// initializer_list supplied to the constructor of `unordered_set`.  Deduce
/// the template parameters `HASH` and `EQUAL` from the other parameters
/// passed to the constructor.  This deduction guide does not participate
/// unless the supplied allocator is convertible to `bsl::allocator<KEY>`.
template <
    class KEY,
    class HASH,
    class EQUAL,
    class ALLOC,
    class DEFAULT_ALLOCATOR = bsl::allocator<KEY>,
    class = bsl::enable_if_t<bsl::is_convertible_v<ALLOC *, DEFAULT_ALLOCATOR>>
    >
unordered_set(std::initializer_list<KEY>,
              typename bsl::allocator_traits<DEFAULT_ALLOCATOR>::size_type,
              HASH,
              EQUAL,
              ALLOC *)
-> unordered_set<KEY, HASH, EQUAL>;

/// Deduce the template parameter `KEY` from the `value_type` of the
/// initializer_list supplied to the constructor of `unordered_set`.  Deduce
/// the template parameters `HASH` and `ALLOCATOR` from the other parameters
/// passed to the constructor.  This deduction guide does not participate
/// unless the supplied `HASH` is invocable with a `KEY`, and the supplied
/// allocator meets the requirements of a standard allocator.
template <
    class KEY,
    class HASH,
    class ALLOCATOR,
    class = bsl::enable_if_t<std::is_invocable_v<HASH, const KEY &>>,
    class = bsl::enable_if_t< bsl::IsStdAllocator_v<ALLOCATOR>>
    >
unordered_set(std::initializer_list<KEY>,
              typename bsl::allocator_traits<ALLOCATOR>::size_type,
              HASH,
              ALLOCATOR)
-> unordered_set<KEY, HASH, bsl::equal_to<KEY>, ALLOCATOR>;

/// Deduce the template parameter `KEY` from the `value_type` of the
/// initializer_list supplied to the constructor of `unordered_set`.  Deduce
/// the template parameter `HASH` from the other parameters passed to the
/// constructor.  This deduction guide does not participate unless the
/// supplied allocator is convertible to `bsl::allocator<KEY>`.
template <
    class KEY,
    class HASH,
    class ALLOC,
    class DEFAULT_ALLOCATOR = bsl::allocator<KEY>,
    class = bsl::enable_if_t<bsl::is_convertible_v<ALLOC *, DEFAULT_ALLOCATOR>>
    >
unordered_set(std::initializer_list<KEY>,
              typename bsl::allocator_traits<DEFAULT_ALLOCATOR>::size_type,
              HASH,
              ALLOC *)
-> unordered_set<KEY, HASH>;

/// Deduce the template parameter `KEY` from the `value_type` of the
/// initializer_list supplied to the constructor of `unordered_set`.  This
/// deduction guide does not participate unless the supplied allocator meets
/// the requirements of a standard allocator.
template <
    class KEY,
    class ALLOCATOR,
    class = bsl::enable_if_t<bsl::IsStdAllocator_v<ALLOCATOR>>
    >
unordered_set(std::initializer_list<KEY>,
              typename bsl::allocator_traits<ALLOCATOR>::size_type,
              ALLOCATOR)
-> unordered_set<KEY, bsl::hash<KEY>, bsl::equal_to<KEY>, ALLOCATOR>;

/// Deduce the template parameter `KEY` from the `value_type` of the
/// initializer_list supplied to the constructor of `unordered_set`.  This
/// deduction guide does not participate unless the supplied allocator is
/// convertible to `bsl::allocator<KEY>`.
template <
    class KEY,
    class ALLOC,
    class DEFAULT_ALLOCATOR = bsl::allocator<KEY>,
    class = bsl::enable_if_t<bsl::is_convertible_v<ALLOC *, DEFAULT_ALLOCATOR>>
    >
unordered_set(std::initializer_list<KEY>,
              typename bsl::allocator_traits<DEFAULT_ALLOCATOR>::size_type,
              ALLOC *)
-> unordered_set<KEY>;

/// Deduce the template parameter `KEY` from the `value_type` of the
/// initializer_list supplied to the constructor of `unordered_set`.  This
/// deduction guide does not participate unless the supplied allocator meets
/// the requirements of a standard allocator.
template <
    class KEY,
    class ALLOCATOR,
    class = bsl::enable_if_t<bsl::IsStdAllocator_v<ALLOCATOR>>
    >
unordered_set(std::initializer_list<KEY>, ALLOCATOR)
-> unordered_set<KEY, bsl::hash<KEY>, bsl::equal_to<KEY>, ALLOCATOR>;

/// Deduce the template parameter `KEY` from the `value_type` of the
/// initializer_list supplied to the constructor of `unordered_set`.  This
/// deduction guide does not participate unless the supplied allocator is
/// convertible to `bsl::allocator<KEY>`.
template <
    class KEY,
    class ALLOC,
    class DEFAULT_ALLOCATOR = bsl::allocator<KEY>,
    class = bsl::enable_if_t<bsl::is_convertible_v<ALLOC *, DEFAULT_ALLOCATOR>>
    >
unordered_set(std::initializer_list<KEY>, ALLOC *)
-> unordered_set<KEY>;
#endif

// FREE OPERATORS

/// Return `true` if the specified `lhs` and `rhs` objects have the same
/// value, and `false` otherwise.  Two `unordered_set` objects have the same
/// value if they have the same number of value-elements, and for each
/// value-element that is contained in `lhs` there is a value-element
/// contained in `rhs` having the same value, and vice-versa.  Note that
/// this method requires that the (template parameter) type `KEY` be
/// `equality-comparable` (see {Requirements on `KEY`}).
template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
bool operator==(const unordered_set<KEY, HASH, EQUAL, ALLOCATOR>& lhs,
                const unordered_set<KEY, HASH, EQUAL, ALLOCATOR>& rhs);

#ifndef BSLS_COMPILERFEATURES_SUPPORT_THREE_WAY_COMPARISON
template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
bool operator!=(const unordered_set<KEY, HASH, EQUAL, ALLOCATOR>& lhs,
                const unordered_set<KEY, HASH, EQUAL, ALLOCATOR>& rhs);
    // Return 'true' if the specified 'lhs' and 'rhs' objects do not have the
    // same value, and 'false' otherwise.  Two 'unordered_set' objects do not
    // have the same value if they do not have the same number of
    // value-elements, or that for some value-element contained in 'lhs' there
    // is not a value-element in 'rhs' having the same value, and vice-versa.
    // Note that this method requires that the (template parameter) type 'KEY'
    // and be 'equality-comparable' (see {Requirements on 'KEY'}).
#endif

// FREE FUNCTIONS

/// Erase all the elements in the specified unordered_set `s` that satisfy
/// the specified predicate `predicate`.  Return the number of elements
/// erased.
template <class KEY, class HASH, class EQUAL, class ALLOCATOR, class PREDICATE>
typename unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::size_type
erase_if(unordered_set<KEY, HASH, EQUAL, ALLOCATOR>& s, PREDICATE predicate);

template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
void swap(unordered_set<KEY, HASH, EQUAL, ALLOCATOR>& a,
          unordered_set<KEY, HASH, EQUAL, ALLOCATOR>& b)
                                BSLS_KEYWORD_NOEXCEPT_SPECIFICATION(
                                    BSLS_KEYWORD_NOEXCEPT_OPERATOR(a.swap(b)));
    // Exchange the value, hasher, key-equality functor, and 'max_load_factor'
    // of the specified 'a' object with those of the specified 'b' object; also
    // exchange the allocator of 'a' with that of 'b' if the (template
    // parameter) type 'ALLOCATOR' has the 'propagate_on_container_swap' trait,
    // and do not modify either allocator otherwise.  This function provides
    // the no-throw exception-safety guarantee if and only if both the
    // (template parameter) types 'HASH' and 'EQUAL' provide no-throw swap
    // operations; if an exception is thrown, both objects are left in valid
    // but unspecified states.  This operation guarantees 'O[1]' complexity.
    // The behavior is undefined unless either 'a' was created with the same
    // allocator as 'b' or 'ALLOCATOR' has the 'propagate_on_container_swap'
    // trait.

// ============================================================================
//                  TEMPLATE AND INLINE FUNCTION DEFINITIONS
// ============================================================================

                        //--------------------
                        // class unordered_set
                        //--------------------

// PRIVATE MANIPULATORS
template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
template <class INPUT_ITERATOR, class SENTINEL>
inline
void unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::constructFromRange(
                                                          INPUT_ITERATOR first,
                                                          SENTINEL       last)
{
    ///Implementation Notes
    ///--------------------
    // If we can calculate the number of elements, reserve space for them
    // upfront to reduce rehashing.  The calculation is done once since
    // `IteratorUtil::insertDistance` may be expensive for non-random-access
    // iterators.

    if (first == last) {
        return;                                                       // RETURN
    }

    if BSLS_KEYWORD_CONSTEXPR_CPP17 (
        BloombergLP::bslstl::IteratorUtil::
                       canCalculateInsertDistance<INPUT_ITERATOR,SENTINEL>()) {
        this->reserve(
               BloombergLP::bslstl::IteratorUtil::insertDistance(first, last));
    }

    bool isInsertedFlag;  // value is not used

    while (first != last) {
        d_impl.insertIfMissing(&isInsertedFlag, *first);
        ++first;
    }
}

#if defined(BSLS_LIBRARYFEATURES_HAS_CPP20_CONCEPTS) \
 && defined(BSLS_LIBRARYFEATURES_HAS_CPP20_RANGES)

template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
template <class INPUT_ITERATOR, class SENTINEL>
inline
void unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::constructFromRange(
                                                    INPUT_ITERATOR first,
                                                    SENTINEL       last,
                                                    size_t         numElements)
{
    BSLS_ASSERT_SAFE((
        !BloombergLP::bslstl::IteratorUtil
                       ::canCalculateInsertDistance<INPUT_ITERATOR, SENTINEL>()
        || numElements == static_cast<size_t>(
             BloombergLP::bslstl::IteratorUtil::insertDistance(first, last))));


    if (0 < numElements) {
        this->reserve(numElements);
    }

    bool isInsertedFlag;  // value is not used

    while (first != last) {
        d_impl.insertIfMissing(&isInsertedFlag, *first);
        ++first;
    }
}

#endif

template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
template <class INPUT_ITERATOR, class SENTINEL>
inline
void unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::insertFromRange(
                                                          INPUT_ITERATOR first,
                                                          SENTINEL       last)
{
    ///Implementation Notes
    ///--------------------
    // If we can calculate the number of elements, reserve space for them
    // upfront to reduce rehashing.  The calculation is done once since
    // `IteratorUtil::insertDistance` may be expensive for non-random-access
    // iterators.

    if BSLS_KEYWORD_CONSTEXPR_CPP17 (BloombergLP::bslstl::IteratorUtil
                    ::canCalculateInsertDistance<INPUT_ITERATOR, SENTINEL>()) {
        this->reserve(this->size()
             + BloombergLP::bslstl::IteratorUtil::insertDistance(first, last));
    }

    bool isInsertedFlag;  // value is not used

    while (first != last) {
        d_impl.insertIfMissing(&isInsertedFlag, *first);
        ++first;
    }
}

#if defined(BSLS_LIBRARYFEATURES_HAS_CPP20_CONCEPTS) \
 && defined(BSLS_LIBRARYFEATURES_HAS_CPP20_RANGES)

template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
template <class INPUT_ITERATOR, class SENTINEL>
inline
void unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::insertFromRange(
                                                    INPUT_ITERATOR first,
                                                    SENTINEL       last,
                                                    size_t         numElements)
{
    BSLS_ASSERT_SAFE((
        !BloombergLP::bslstl::IteratorUtil
                       ::canCalculateInsertDistance<INPUT_ITERATOR, SENTINEL>()
        || numElements == static_cast<size_t>(
             BloombergLP::bslstl::IteratorUtil::insertDistance(first, last))));

    this->reserve(this->size() + numElements);

    bool isInsertedFlag;  // value is not used

    while (first != last) {
        d_impl.insertIfMissing(&isInsertedFlag, *first);
        ++first;
    }
}

#endif

// CREATORS
template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
inline
unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::unordered_set()
: d_impl(HASH(), EQUAL(), 0, 1.0f, ALLOCATOR())
{
}

template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
inline
unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::unordered_set(
                                            size_type        initialNumBuckets,
                                            const HASH&      hashFunction,
                                            const EQUAL&     keyEqual,
                                            const ALLOCATOR& basicAllocator)
: d_impl(hashFunction, keyEqual, initialNumBuckets, 1.0f, basicAllocator)
{
}

template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
inline
unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::unordered_set(
                                            size_type        initialNumBuckets,
                                            const HASH&      hashFunction,
                                            const ALLOCATOR& basicAllocator)
: d_impl(hashFunction, EQUAL(), initialNumBuckets, 1.0f, basicAllocator)
{
}

template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
inline
unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::unordered_set(
                                            size_type        initialNumBuckets,
                                            const ALLOCATOR& basicAllocator)
: d_impl(HASH(), EQUAL(), initialNumBuckets, 1.0f, basicAllocator)
{
}

template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
inline
unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::unordered_set(
                                               const ALLOCATOR& basicAllocator)
: d_impl(basicAllocator)
{
}

template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
inline
unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::unordered_set(
                                                 const unordered_set& original)
: d_impl(original.d_impl,
         AllocatorTraits::select_on_container_copy_construction(
                                                     original.get_allocator()))
{
}

template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
inline
unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::unordered_set(
                        BloombergLP::bslmf::MovableRef<unordered_set> original)
: d_impl(MoveUtil::move(MoveUtil::access(original).d_impl))
{
}

template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
inline
unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::unordered_set(
                 const unordered_set&                           original,
                 const typename type_identity<ALLOCATOR>::type& basicAllocator)
: d_impl(original.d_impl, basicAllocator)
{
}

template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
inline
unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::unordered_set(
                 BloombergLP::bslmf::MovableRef<unordered_set>  original,
                 const typename type_identity<ALLOCATOR>::type& basicAllocator)
: d_impl(MoveUtil::move(MoveUtil::access(original).d_impl), basicAllocator)
{
}

template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
template <class INPUT_ITERATOR>
inline
unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::unordered_set(
                                            INPUT_ITERATOR   first,
                                            INPUT_ITERATOR   last,
                                            size_type        initialNumBuckets,
                                            const HASH&      hashFunction,
                                            const EQUAL&     keyEqual,
                                            const ALLOCATOR& basicAllocator)
: d_impl(hashFunction, keyEqual, initialNumBuckets, 1.0f, basicAllocator)
{
    constructFromRange(first, last);
}

template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
template <class INPUT_ITERATOR>
inline
unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::unordered_set(
                                            INPUT_ITERATOR   first,
                                            INPUT_ITERATOR   last,
                                            size_type        initialNumBuckets,
                                            const HASH&      hashFunction,
                                            const ALLOCATOR& basicAllocator)
: d_impl(hashFunction, EQUAL(), initialNumBuckets, 1.0f, basicAllocator)
{
    constructFromRange(first, last);
}

template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
template <class INPUT_ITERATOR>
inline
unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::unordered_set(
                                            INPUT_ITERATOR   first,
                                            INPUT_ITERATOR   last,
                                            size_type        initialNumBuckets,
                                            const ALLOCATOR& basicAllocator)
: d_impl(HASH(), EQUAL(), initialNumBuckets, 1.0f, basicAllocator)
{
    constructFromRange(first, last);
}

template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
template <class INPUT_ITERATOR>
inline
unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::unordered_set(
                                               INPUT_ITERATOR   first,
                                               INPUT_ITERATOR   last,
                                               const ALLOCATOR& basicAllocator)
: d_impl(HASH(), EQUAL(), 0, 1.0f, basicAllocator)
{
    constructFromRange(first, last);
}

#if defined(BSLS_COMPILERFEATURES_SUPPORT_GENERALIZED_INITIALIZERS)
template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
#ifdef BSLS_COMPILERFEATURES_SUPPORT_CTAD
template <class, class, class>
#endif
inline
unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::unordered_set(
                                  std::initializer_list<KEY> values,
                                  size_type                  initialNumBuckets,
                                  const hasher&              hashFunction,
                                  const key_equal&           keyEqual,
                                  const ALLOCATOR&           basicAllocator)
: unordered_set(values.begin(), values.end(), initialNumBuckets,
                hashFunction, keyEqual, basicAllocator)
{
}

template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
#ifdef BSLS_COMPILERFEATURES_SUPPORT_CTAD
template <class, class>
#endif
inline
unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::unordered_set(
                                  std::initializer_list<KEY> values,
                                  size_type                  initialNumBuckets,
                                  const HASH&                hashFunction,
                                  const ALLOCATOR&           basicAllocator)
: unordered_set(values.begin(),
                values.end(),
                initialNumBuckets,
                hashFunction,
                EQUAL(),
                basicAllocator)
{
}

template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
#ifdef BSLS_COMPILERFEATURES_SUPPORT_CTAD
template <class>
#endif
inline
unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::unordered_set(
                                 std::initializer_list<KEY> values,
                                 size_type                  initialNumBuckets,
                                 const ALLOCATOR&           basicAllocator)
: unordered_set(values.begin(),
                values.end(),
                initialNumBuckets,
                HASH(),
                EQUAL(),
                basicAllocator)
{
}

template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
#ifdef BSLS_COMPILERFEATURES_SUPPORT_CTAD
template <class>
#endif
inline
unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::unordered_set(
                                 std::initializer_list<KEY> values,
                                 const ALLOCATOR&           basicAllocator)
: unordered_set(values.begin(),
                values.end(),
                0,
                HASH(),
                EQUAL(),
                basicAllocator)
{
}

#endif

template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
inline
unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::~unordered_set()
{
    // All memory management is handled by the base 'd_impl' member.
}

// MANIPULATORS
template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
inline
unordered_set<KEY, HASH, EQUAL, ALLOCATOR>&
unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::operator=(const unordered_set& rhs)
{
    // Note that we have delegated responsibility for correct handling of
    // allocator propagation to the 'HashTable' implementation.

    d_impl = rhs.d_impl;

    return *this;
}

template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
inline
unordered_set<KEY, HASH, EQUAL, ALLOCATOR>&
unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::operator=(
                             BloombergLP::bslmf::MovableRef<unordered_set> rhs)
                             BSLS_KEYWORD_NOEXCEPT_SPECIFICATION(
                                 AllocatorTraits::is_always_equal::value
                              && std::is_nothrow_move_assignable<HASH>::value
                              && std::is_nothrow_move_assignable<EQUAL>::value)
{
    // Note that we have delegated responsibility for correct handling of
    // allocator propagation to the 'HashTable' implementation.

    unordered_set& lvalue = rhs;

    d_impl = MoveUtil::move(lvalue.d_impl);

    return *this;
}

#if defined(BSLS_COMPILERFEATURES_SUPPORT_GENERALIZED_INITIALIZERS)
template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
inline
unordered_set<KEY, HASH, EQUAL, ALLOCATOR>&
unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::operator=(
                                             std::initializer_list<KEY> values)
{
    unordered_set tmp(values, d_impl.allocator());

    d_impl.swap(tmp.d_impl);

    return *this;
}
#endif

template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
inline
typename unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::iterator
unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::begin() BSLS_KEYWORD_NOEXCEPT
{
    return iterator(d_impl.elementListRoot());
}

template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
inline
typename unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::iterator
unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::end() BSLS_KEYWORD_NOEXCEPT
{
    return iterator();
}

template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
inline
typename unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::local_iterator
unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::begin(size_type index)
{
    BSLS_ASSERT_SAFE(index < this->bucket_count());

    return local_iterator(&d_impl.bucketAtIndex(index));
}

template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
inline
typename unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::local_iterator
unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::end(size_type index)
{
    BSLS_ASSERT_SAFE(index < this->bucket_count());

    return local_iterator(0, &d_impl.bucketAtIndex(index));
}

template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
inline
void unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::clear() BSLS_KEYWORD_NOEXCEPT
{
    d_impl.removeAll();
}

#if BSLS_COMPILERFEATURES_SIMULATE_VARIADIC_TEMPLATES
// {{{ BEGIN GENERATED CODE
// Command line: sim_cpp11_features.pl bslstl_unorderedset.h
#ifndef BSLSTL_UNORDEREDSET_VARIADIC_LIMIT
#define BSLSTL_UNORDEREDSET_VARIADIC_LIMIT 10
#endif
#ifndef BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_D
#define BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_D BSLSTL_UNORDEREDSET_VARIADIC_LIMIT
#endif
#if BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_D >= 0
template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
inline
pair<typename unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::iterator, bool>
unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::emplace(
                          )
{
    typedef bsl::pair<iterator, bool> ResultType;

    bool isInsertedFlag = false;

    HashTableLink *result = d_impl.emplaceIfMissing(
           &isInsertedFlag);

    return ResultType(iterator(result), isInsertedFlag);
}
#endif  // BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_D >= 0

#if BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_D >= 1
template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
template <class Args_01>
inline
pair<typename unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::iterator, bool>
unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::emplace(
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_01) arguments_01)
{
    typedef bsl::pair<iterator, bool> ResultType;

    bool isInsertedFlag = false;

    HashTableLink *result = d_impl.emplaceIfMissing(
           &isInsertedFlag,
                         BSLS_COMPILERFEATURES_FORWARD(Args_01, arguments_01));

    return ResultType(iterator(result), isInsertedFlag);
}
#endif  // BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_D >= 1

#if BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_D >= 2
template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
template <class Args_01,
          class Args_02>
inline
pair<typename unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::iterator, bool>
unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::emplace(
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_01) arguments_01,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_02) arguments_02)
{
    typedef bsl::pair<iterator, bool> ResultType;

    bool isInsertedFlag = false;

    HashTableLink *result = d_impl.emplaceIfMissing(
           &isInsertedFlag,
                         BSLS_COMPILERFEATURES_FORWARD(Args_01, arguments_01),
                         BSLS_COMPILERFEATURES_FORWARD(Args_02, arguments_02));

    return ResultType(iterator(result), isInsertedFlag);
}
#endif  // BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_D >= 2

#if BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_D >= 3
template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
template <class Args_01,
          class Args_02,
          class Args_03>
inline
pair<typename unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::iterator, bool>
unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::emplace(
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_01) arguments_01,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_02) arguments_02,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_03) arguments_03)
{
    typedef bsl::pair<iterator, bool> ResultType;

    bool isInsertedFlag = false;

    HashTableLink *result = d_impl.emplaceIfMissing(
           &isInsertedFlag,
                         BSLS_COMPILERFEATURES_FORWARD(Args_01, arguments_01),
                         BSLS_COMPILERFEATURES_FORWARD(Args_02, arguments_02),
                         BSLS_COMPILERFEATURES_FORWARD(Args_03, arguments_03));

    return ResultType(iterator(result), isInsertedFlag);
}
#endif  // BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_D >= 3

#if BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_D >= 4
template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
template <class Args_01,
          class Args_02,
          class Args_03,
          class Args_04>
inline
pair<typename unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::iterator, bool>
unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::emplace(
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_01) arguments_01,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_02) arguments_02,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_03) arguments_03,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_04) arguments_04)
{
    typedef bsl::pair<iterator, bool> ResultType;

    bool isInsertedFlag = false;

    HashTableLink *result = d_impl.emplaceIfMissing(
           &isInsertedFlag,
                         BSLS_COMPILERFEATURES_FORWARD(Args_01, arguments_01),
                         BSLS_COMPILERFEATURES_FORWARD(Args_02, arguments_02),
                         BSLS_COMPILERFEATURES_FORWARD(Args_03, arguments_03),
                         BSLS_COMPILERFEATURES_FORWARD(Args_04, arguments_04));

    return ResultType(iterator(result), isInsertedFlag);
}
#endif  // BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_D >= 4

#if BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_D >= 5
template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
template <class Args_01,
          class Args_02,
          class Args_03,
          class Args_04,
          class Args_05>
inline
pair<typename unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::iterator, bool>
unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::emplace(
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_01) arguments_01,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_02) arguments_02,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_03) arguments_03,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_04) arguments_04,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_05) arguments_05)
{
    typedef bsl::pair<iterator, bool> ResultType;

    bool isInsertedFlag = false;

    HashTableLink *result = d_impl.emplaceIfMissing(
           &isInsertedFlag,
                         BSLS_COMPILERFEATURES_FORWARD(Args_01, arguments_01),
                         BSLS_COMPILERFEATURES_FORWARD(Args_02, arguments_02),
                         BSLS_COMPILERFEATURES_FORWARD(Args_03, arguments_03),
                         BSLS_COMPILERFEATURES_FORWARD(Args_04, arguments_04),
                         BSLS_COMPILERFEATURES_FORWARD(Args_05, arguments_05));

    return ResultType(iterator(result), isInsertedFlag);
}
#endif  // BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_D >= 5

#if BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_D >= 6
template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
template <class Args_01,
          class Args_02,
          class Args_03,
          class Args_04,
          class Args_05,
          class Args_06>
inline
pair<typename unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::iterator, bool>
unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::emplace(
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_01) arguments_01,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_02) arguments_02,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_03) arguments_03,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_04) arguments_04,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_05) arguments_05,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_06) arguments_06)
{
    typedef bsl::pair<iterator, bool> ResultType;

    bool isInsertedFlag = false;

    HashTableLink *result = d_impl.emplaceIfMissing(
           &isInsertedFlag,
                         BSLS_COMPILERFEATURES_FORWARD(Args_01, arguments_01),
                         BSLS_COMPILERFEATURES_FORWARD(Args_02, arguments_02),
                         BSLS_COMPILERFEATURES_FORWARD(Args_03, arguments_03),
                         BSLS_COMPILERFEATURES_FORWARD(Args_04, arguments_04),
                         BSLS_COMPILERFEATURES_FORWARD(Args_05, arguments_05),
                         BSLS_COMPILERFEATURES_FORWARD(Args_06, arguments_06));

    return ResultType(iterator(result), isInsertedFlag);
}
#endif  // BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_D >= 6

#if BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_D >= 7
template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
template <class Args_01,
          class Args_02,
          class Args_03,
          class Args_04,
          class Args_05,
          class Args_06,
          class Args_07>
inline
pair<typename unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::iterator, bool>
unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::emplace(
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_01) arguments_01,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_02) arguments_02,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_03) arguments_03,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_04) arguments_04,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_05) arguments_05,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_06) arguments_06,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_07) arguments_07)
{
    typedef bsl::pair<iterator, bool> ResultType;

    bool isInsertedFlag = false;

    HashTableLink *result = d_impl.emplaceIfMissing(
           &isInsertedFlag,
                         BSLS_COMPILERFEATURES_FORWARD(Args_01, arguments_01),
                         BSLS_COMPILERFEATURES_FORWARD(Args_02, arguments_02),
                         BSLS_COMPILERFEATURES_FORWARD(Args_03, arguments_03),
                         BSLS_COMPILERFEATURES_FORWARD(Args_04, arguments_04),
                         BSLS_COMPILERFEATURES_FORWARD(Args_05, arguments_05),
                         BSLS_COMPILERFEATURES_FORWARD(Args_06, arguments_06),
                         BSLS_COMPILERFEATURES_FORWARD(Args_07, arguments_07));

    return ResultType(iterator(result), isInsertedFlag);
}
#endif  // BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_D >= 7

#if BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_D >= 8
template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
template <class Args_01,
          class Args_02,
          class Args_03,
          class Args_04,
          class Args_05,
          class Args_06,
          class Args_07,
          class Args_08>
inline
pair<typename unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::iterator, bool>
unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::emplace(
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_01) arguments_01,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_02) arguments_02,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_03) arguments_03,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_04) arguments_04,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_05) arguments_05,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_06) arguments_06,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_07) arguments_07,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_08) arguments_08)
{
    typedef bsl::pair<iterator, bool> ResultType;

    bool isInsertedFlag = false;

    HashTableLink *result = d_impl.emplaceIfMissing(
           &isInsertedFlag,
                         BSLS_COMPILERFEATURES_FORWARD(Args_01, arguments_01),
                         BSLS_COMPILERFEATURES_FORWARD(Args_02, arguments_02),
                         BSLS_COMPILERFEATURES_FORWARD(Args_03, arguments_03),
                         BSLS_COMPILERFEATURES_FORWARD(Args_04, arguments_04),
                         BSLS_COMPILERFEATURES_FORWARD(Args_05, arguments_05),
                         BSLS_COMPILERFEATURES_FORWARD(Args_06, arguments_06),
                         BSLS_COMPILERFEATURES_FORWARD(Args_07, arguments_07),
                         BSLS_COMPILERFEATURES_FORWARD(Args_08, arguments_08));

    return ResultType(iterator(result), isInsertedFlag);
}
#endif  // BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_D >= 8

#if BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_D >= 9
template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
template <class Args_01,
          class Args_02,
          class Args_03,
          class Args_04,
          class Args_05,
          class Args_06,
          class Args_07,
          class Args_08,
          class Args_09>
inline
pair<typename unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::iterator, bool>
unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::emplace(
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_01) arguments_01,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_02) arguments_02,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_03) arguments_03,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_04) arguments_04,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_05) arguments_05,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_06) arguments_06,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_07) arguments_07,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_08) arguments_08,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_09) arguments_09)
{
    typedef bsl::pair<iterator, bool> ResultType;

    bool isInsertedFlag = false;

    HashTableLink *result = d_impl.emplaceIfMissing(
           &isInsertedFlag,
                         BSLS_COMPILERFEATURES_FORWARD(Args_01, arguments_01),
                         BSLS_COMPILERFEATURES_FORWARD(Args_02, arguments_02),
                         BSLS_COMPILERFEATURES_FORWARD(Args_03, arguments_03),
                         BSLS_COMPILERFEATURES_FORWARD(Args_04, arguments_04),
                         BSLS_COMPILERFEATURES_FORWARD(Args_05, arguments_05),
                         BSLS_COMPILERFEATURES_FORWARD(Args_06, arguments_06),
                         BSLS_COMPILERFEATURES_FORWARD(Args_07, arguments_07),
                         BSLS_COMPILERFEATURES_FORWARD(Args_08, arguments_08),
                         BSLS_COMPILERFEATURES_FORWARD(Args_09, arguments_09));

    return ResultType(iterator(result), isInsertedFlag);
}
#endif  // BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_D >= 9

#if BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_D >= 10
template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
template <class Args_01,
          class Args_02,
          class Args_03,
          class Args_04,
          class Args_05,
          class Args_06,
          class Args_07,
          class Args_08,
          class Args_09,
          class Args_10>
inline
pair<typename unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::iterator, bool>
unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::emplace(
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_01) arguments_01,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_02) arguments_02,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_03) arguments_03,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_04) arguments_04,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_05) arguments_05,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_06) arguments_06,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_07) arguments_07,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_08) arguments_08,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_09) arguments_09,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_10) arguments_10)
{
    typedef bsl::pair<iterator, bool> ResultType;

    bool isInsertedFlag = false;

    HashTableLink *result = d_impl.emplaceIfMissing(
           &isInsertedFlag,
                         BSLS_COMPILERFEATURES_FORWARD(Args_01, arguments_01),
                         BSLS_COMPILERFEATURES_FORWARD(Args_02, arguments_02),
                         BSLS_COMPILERFEATURES_FORWARD(Args_03, arguments_03),
                         BSLS_COMPILERFEATURES_FORWARD(Args_04, arguments_04),
                         BSLS_COMPILERFEATURES_FORWARD(Args_05, arguments_05),
                         BSLS_COMPILERFEATURES_FORWARD(Args_06, arguments_06),
                         BSLS_COMPILERFEATURES_FORWARD(Args_07, arguments_07),
                         BSLS_COMPILERFEATURES_FORWARD(Args_08, arguments_08),
                         BSLS_COMPILERFEATURES_FORWARD(Args_09, arguments_09),
                         BSLS_COMPILERFEATURES_FORWARD(Args_10, arguments_10));

    return ResultType(iterator(result), isInsertedFlag);
}
#endif  // BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_D >= 10


#if BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_D >= 0
template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
inline
typename unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::iterator
unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::emplace_hint(const_iterator)
{

    return
        this->emplace().first;
}
#endif  // BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_D >= 0

#if BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_D >= 1
template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
template <class Args_01>
inline
typename unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::iterator
unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::emplace_hint(const_iterator,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_01) arguments_01)
{

    return
        this->emplace(BSLS_COMPILERFEATURES_FORWARD(Args_01, arguments_01)
                      ).first;
}
#endif  // BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_D >= 1

#if BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_D >= 2
template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
template <class Args_01,
          class Args_02>
inline
typename unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::iterator
unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::emplace_hint(const_iterator,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_01) arguments_01,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_02) arguments_02)
{

    return
        this->emplace(BSLS_COMPILERFEATURES_FORWARD(Args_01, arguments_01),
                      BSLS_COMPILERFEATURES_FORWARD(Args_02, arguments_02)
                      ).first;
}
#endif  // BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_D >= 2

#if BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_D >= 3
template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
template <class Args_01,
          class Args_02,
          class Args_03>
inline
typename unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::iterator
unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::emplace_hint(const_iterator,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_01) arguments_01,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_02) arguments_02,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_03) arguments_03)
{

    return
        this->emplace(BSLS_COMPILERFEATURES_FORWARD(Args_01, arguments_01),
                      BSLS_COMPILERFEATURES_FORWARD(Args_02, arguments_02),
                      BSLS_COMPILERFEATURES_FORWARD(Args_03, arguments_03)
                      ).first;
}
#endif  // BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_D >= 3

#if BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_D >= 4
template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
template <class Args_01,
          class Args_02,
          class Args_03,
          class Args_04>
inline
typename unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::iterator
unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::emplace_hint(const_iterator,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_01) arguments_01,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_02) arguments_02,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_03) arguments_03,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_04) arguments_04)
{

    return
        this->emplace(BSLS_COMPILERFEATURES_FORWARD(Args_01, arguments_01),
                      BSLS_COMPILERFEATURES_FORWARD(Args_02, arguments_02),
                      BSLS_COMPILERFEATURES_FORWARD(Args_03, arguments_03),
                      BSLS_COMPILERFEATURES_FORWARD(Args_04, arguments_04)
                      ).first;
}
#endif  // BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_D >= 4

#if BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_D >= 5
template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
template <class Args_01,
          class Args_02,
          class Args_03,
          class Args_04,
          class Args_05>
inline
typename unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::iterator
unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::emplace_hint(const_iterator,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_01) arguments_01,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_02) arguments_02,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_03) arguments_03,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_04) arguments_04,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_05) arguments_05)
{

    return
        this->emplace(BSLS_COMPILERFEATURES_FORWARD(Args_01, arguments_01),
                      BSLS_COMPILERFEATURES_FORWARD(Args_02, arguments_02),
                      BSLS_COMPILERFEATURES_FORWARD(Args_03, arguments_03),
                      BSLS_COMPILERFEATURES_FORWARD(Args_04, arguments_04),
                      BSLS_COMPILERFEATURES_FORWARD(Args_05, arguments_05)
                      ).first;
}
#endif  // BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_D >= 5

#if BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_D >= 6
template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
template <class Args_01,
          class Args_02,
          class Args_03,
          class Args_04,
          class Args_05,
          class Args_06>
inline
typename unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::iterator
unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::emplace_hint(const_iterator,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_01) arguments_01,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_02) arguments_02,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_03) arguments_03,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_04) arguments_04,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_05) arguments_05,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_06) arguments_06)
{

    return
        this->emplace(BSLS_COMPILERFEATURES_FORWARD(Args_01, arguments_01),
                      BSLS_COMPILERFEATURES_FORWARD(Args_02, arguments_02),
                      BSLS_COMPILERFEATURES_FORWARD(Args_03, arguments_03),
                      BSLS_COMPILERFEATURES_FORWARD(Args_04, arguments_04),
                      BSLS_COMPILERFEATURES_FORWARD(Args_05, arguments_05),
                      BSLS_COMPILERFEATURES_FORWARD(Args_06, arguments_06)
                      ).first;
}
#endif  // BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_D >= 6

#if BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_D >= 7
template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
template <class Args_01,
          class Args_02,
          class Args_03,
          class Args_04,
          class Args_05,
          class Args_06,
          class Args_07>
inline
typename unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::iterator
unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::emplace_hint(const_iterator,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_01) arguments_01,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_02) arguments_02,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_03) arguments_03,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_04) arguments_04,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_05) arguments_05,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_06) arguments_06,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_07) arguments_07)
{

    return
        this->emplace(BSLS_COMPILERFEATURES_FORWARD(Args_01, arguments_01),
                      BSLS_COMPILERFEATURES_FORWARD(Args_02, arguments_02),
                      BSLS_COMPILERFEATURES_FORWARD(Args_03, arguments_03),
                      BSLS_COMPILERFEATURES_FORWARD(Args_04, arguments_04),
                      BSLS_COMPILERFEATURES_FORWARD(Args_05, arguments_05),
                      BSLS_COMPILERFEATURES_FORWARD(Args_06, arguments_06),
                      BSLS_COMPILERFEATURES_FORWARD(Args_07, arguments_07)
                      ).first;
}
#endif  // BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_D >= 7

#if BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_D >= 8
template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
template <class Args_01,
          class Args_02,
          class Args_03,
          class Args_04,
          class Args_05,
          class Args_06,
          class Args_07,
          class Args_08>
inline
typename unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::iterator
unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::emplace_hint(const_iterator,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_01) arguments_01,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_02) arguments_02,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_03) arguments_03,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_04) arguments_04,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_05) arguments_05,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_06) arguments_06,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_07) arguments_07,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_08) arguments_08)
{

    return
        this->emplace(BSLS_COMPILERFEATURES_FORWARD(Args_01, arguments_01),
                      BSLS_COMPILERFEATURES_FORWARD(Args_02, arguments_02),
                      BSLS_COMPILERFEATURES_FORWARD(Args_03, arguments_03),
                      BSLS_COMPILERFEATURES_FORWARD(Args_04, arguments_04),
                      BSLS_COMPILERFEATURES_FORWARD(Args_05, arguments_05),
                      BSLS_COMPILERFEATURES_FORWARD(Args_06, arguments_06),
                      BSLS_COMPILERFEATURES_FORWARD(Args_07, arguments_07),
                      BSLS_COMPILERFEATURES_FORWARD(Args_08, arguments_08)
                      ).first;
}
#endif  // BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_D >= 8

#if BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_D >= 9
template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
template <class Args_01,
          class Args_02,
          class Args_03,
          class Args_04,
          class Args_05,
          class Args_06,
          class Args_07,
          class Args_08,
          class Args_09>
inline
typename unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::iterator
unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::emplace_hint(const_iterator,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_01) arguments_01,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_02) arguments_02,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_03) arguments_03,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_04) arguments_04,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_05) arguments_05,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_06) arguments_06,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_07) arguments_07,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_08) arguments_08,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_09) arguments_09)
{

    return
        this->emplace(BSLS_COMPILERFEATURES_FORWARD(Args_01, arguments_01),
                      BSLS_COMPILERFEATURES_FORWARD(Args_02, arguments_02),
                      BSLS_COMPILERFEATURES_FORWARD(Args_03, arguments_03),
                      BSLS_COMPILERFEATURES_FORWARD(Args_04, arguments_04),
                      BSLS_COMPILERFEATURES_FORWARD(Args_05, arguments_05),
                      BSLS_COMPILERFEATURES_FORWARD(Args_06, arguments_06),
                      BSLS_COMPILERFEATURES_FORWARD(Args_07, arguments_07),
                      BSLS_COMPILERFEATURES_FORWARD(Args_08, arguments_08),
                      BSLS_COMPILERFEATURES_FORWARD(Args_09, arguments_09)
                      ).first;
}
#endif  // BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_D >= 9

#if BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_D >= 10
template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
template <class Args_01,
          class Args_02,
          class Args_03,
          class Args_04,
          class Args_05,
          class Args_06,
          class Args_07,
          class Args_08,
          class Args_09,
          class Args_10>
inline
typename unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::iterator
unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::emplace_hint(const_iterator,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_01) arguments_01,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_02) arguments_02,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_03) arguments_03,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_04) arguments_04,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_05) arguments_05,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_06) arguments_06,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_07) arguments_07,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_08) arguments_08,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_09) arguments_09,
                       BSLS_COMPILERFEATURES_FORWARD_REF(Args_10) arguments_10)
{

    return
        this->emplace(BSLS_COMPILERFEATURES_FORWARD(Args_01, arguments_01),
                      BSLS_COMPILERFEATURES_FORWARD(Args_02, arguments_02),
                      BSLS_COMPILERFEATURES_FORWARD(Args_03, arguments_03),
                      BSLS_COMPILERFEATURES_FORWARD(Args_04, arguments_04),
                      BSLS_COMPILERFEATURES_FORWARD(Args_05, arguments_05),
                      BSLS_COMPILERFEATURES_FORWARD(Args_06, arguments_06),
                      BSLS_COMPILERFEATURES_FORWARD(Args_07, arguments_07),
                      BSLS_COMPILERFEATURES_FORWARD(Args_08, arguments_08),
                      BSLS_COMPILERFEATURES_FORWARD(Args_09, arguments_09),
                      BSLS_COMPILERFEATURES_FORWARD(Args_10, arguments_10)
                      ).first;
}
#endif  // BSLSTL_UNORDEREDSET_VARIADIC_LIMIT_D >= 10

#else
// The generated code below is a workaround for the absence of perfect
// forwarding in some compilers.
template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
template <class... Args>
inline
pair<typename unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::iterator, bool>
unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::emplace(
                          BSLS_COMPILERFEATURES_FORWARD_REF(Args)... arguments)
{
    typedef bsl::pair<iterator, bool> ResultType;

    bool isInsertedFlag = false;

    HashTableLink *result = d_impl.emplaceIfMissing(
           &isInsertedFlag, BSLS_COMPILERFEATURES_FORWARD(Args, arguments)...);

    return ResultType(iterator(result), isInsertedFlag);
}

template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
template <class... Args>
inline
typename unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::iterator
unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::emplace_hint(const_iterator,
                          BSLS_COMPILERFEATURES_FORWARD_REF(Args)... arguments)
{

    return
        this->emplace(BSLS_COMPILERFEATURES_FORWARD(Args, arguments)...).first;
}
// }}} END GENERATED CODE
#endif

template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
inline
bsl::pair<typename unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::iterator,
          typename unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::iterator>
unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::equal_range(const key_type& key)
{
    typedef bsl::pair<iterator, iterator> ResultType;

    iterator first  = this->find(key);
    if (first == this->end()) {
        return ResultType(first, first);                              // RETURN
    }
    else {
        iterator next = first;
        return ResultType(first, ++next);                             // RETURN
    }
}

template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
inline
typename unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::iterator
unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::erase(const_iterator position)
{
    BSLS_ASSERT_SAFE(position != this->end());

    return iterator(d_impl.remove(position.node()));
}

template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
inline
typename unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::size_type
unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::erase(const key_type& key)
{
    if (HashTableLink *target = d_impl.find(key)) {
        d_impl.remove(target);
        return 1;                                                     // RETURN
    }
    else {
        return 0;                                                     // RETURN
    }
}

template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
inline
typename unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::iterator
unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::erase(const_iterator first,
                                                  const_iterator last)
{
#if defined BDE_BUILD_TARGET_SAFE_2
    if (first != last) {
        iterator it        = this->begin();
        const iterator end = this->end();
        for (; it != first; ++it) {
            BSLS_ASSERT(last != it);
            BSLS_ASSERT(end  != it);
        }
        for (; it != last; ++it) {
            BSLS_ASSERT(end  != it);
        }
    }
#endif

    while (first != last) {
        first = this->erase(first);
    }

    return iterator(first.node());          // convert from const_iterator
}

template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
inline
typename unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::iterator
unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::find(const key_type& key)
{
    return iterator(d_impl.find(key));
}

template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
inline
bsl::pair<typename unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::iterator, bool>
unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::insert(const value_type& value)
{
    typedef bsl::pair<iterator, bool> ResultType;

    bool isInsertedFlag = false;

    HashTableLink *result = d_impl.insertIfMissing(&isInsertedFlag, value);

    return ResultType(iterator(result), isInsertedFlag);
}

template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
inline
bsl::pair<typename unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::iterator, bool>
unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::insert(
                              BloombergLP::bslmf::MovableRef<value_type> value)
{
    typedef bsl::pair<iterator, bool> ResultType;

    bool isInsertedFlag = false;

    HashTableLink *result = d_impl.insertIfMissing(&isInsertedFlag,
                                                   MoveUtil::move(value));

    return ResultType(iterator(result), isInsertedFlag);
}

template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
inline
typename unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::iterator
unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::insert(const_iterator,
                                                   const value_type& value)
{
    // There is no realistic use-case for the 'hint' in an 'unordered_set' of
    // unique values.  We could quickly test for a duplicate key, and have a
    // fast return path for when the method fails, but in the typical use case
    // where a new element is inserted, we are adding an extra key-check for no
    // benefit.  In order to insert an element into a bucket, we need to walk
    // the whole bucket looking for duplicates, and the hint is no help in
    // finding the start of a bucket.

    return this->insert(value).first;
}

template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
inline
typename unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::iterator
unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::insert(
                              const_iterator,
                              BloombergLP::bslmf::MovableRef<value_type> value)
{
    // There is no realistic use-case for the 'hint' in an 'unordered_set' of
    // unique values.  We could quickly test for a duplicate key, and have a
    // fast return path for when the method fails, but in the typical use case
    // where a new element is inserted, we are adding an extra key-check for no
    // benefit.  In order to insert an element into a bucket, we need to walk
    // the whole bucket looking for duplicates, and the hint is no help in
    // finding the start of a bucket.

    return this->insert(MoveUtil::move(value)).first;
}

template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
template <class INPUT_ITERATOR>
inline
void unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::insert(INPUT_ITERATOR first,
                                                        INPUT_ITERATOR last)
{
    insertFromRange(first, last);
}

#if defined(BSLS_COMPILERFEATURES_SUPPORT_GENERALIZED_INITIALIZERS)
template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
inline
void unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::insert(
                                             std::initializer_list<KEY> values)
{
    insert(values.begin(), values.end());
}
#endif

template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
inline
void unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::max_load_factor(
                                                           float newLoadFactor)
{
    d_impl.setMaxLoadFactor(newLoadFactor);
}

template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
inline
void unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::rehash(size_type numBuckets)
{
    d_impl.rehashForNumBuckets(numBuckets);
}

template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
inline
void
unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::reserve(size_type numElements)
{
    d_impl.reserveForNumElements(numElements);
}

template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
inline
void unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::swap(unordered_set& other)
                                   BSLS_KEYWORD_NOEXCEPT_SPECIFICATION(
                                       AllocatorTraits::is_always_equal::value
                                   &&  bsl::is_nothrow_swappable<HASH>::value
                                   &&  bsl::is_nothrow_swappable<EQUAL>::value)
{
    d_impl.swap(other.d_impl);
}

// ACCESSORS
template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
inline
ALLOCATOR unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::get_allocator() const
                                                          BSLS_KEYWORD_NOEXCEPT
{
    return d_impl.allocator();
}

template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
inline
typename unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::const_iterator
unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::begin() const BSLS_KEYWORD_NOEXCEPT
{
    return const_iterator(d_impl.elementListRoot());
}

template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
inline
typename unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::const_iterator
unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::end() const BSLS_KEYWORD_NOEXCEPT
{
    return const_iterator();
}

template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
inline
typename unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::const_iterator
unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::cbegin() const
                                                          BSLS_KEYWORD_NOEXCEPT
{
    return const_iterator(d_impl.elementListRoot());
}

template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
inline
typename unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::const_iterator
unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::cend() const BSLS_KEYWORD_NOEXCEPT
{
    return const_iterator();
}

template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
inline
bool unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::contains(
                                                     const key_type& key) const
{
    return find(key) != end();
}

template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
inline
bool
unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::empty() const BSLS_KEYWORD_NOEXCEPT
{
    return 0 == d_impl.size();
}

template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
inline
typename unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::size_type
unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::size() const BSLS_KEYWORD_NOEXCEPT
{
    return d_impl.size();
}

template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
inline
typename unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::size_type
unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::max_size() const
                                                          BSLS_KEYWORD_NOEXCEPT
{
    return AllocatorTraits::max_size(get_allocator());
}

template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
inline
typename unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::hasher
unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::hash_function() const
{
    return d_impl.hasher();
}

template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
inline
typename unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::key_equal
unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::key_eq() const
{
    return d_impl.comparator();
}

template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
inline
typename unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::const_iterator
unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::find(const key_type& key) const
{
    return const_iterator(d_impl.find(key));
}

template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
inline
typename unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::size_type
unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::count(const key_type& key) const
{
    return 0 != d_impl.find(key);
}

template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
inline
bsl::pair<typename unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::const_iterator,
          typename unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::const_iterator>
unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::equal_range(
                                                     const key_type& key) const
{
    typedef bsl::pair<const_iterator, const_iterator> ResultType;

    const_iterator first = this->find(key);
    if (first == this->end()) {
        return ResultType(first, first);                              // RETURN
    }
    else {
        const_iterator next = first;
        return ResultType(first, ++next);                             // RETURN
    }
}

template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
inline
typename unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::size_type
unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::bucket_count() const
                                                          BSLS_KEYWORD_NOEXCEPT
{
    return d_impl.numBuckets();
}

template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
inline
typename unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::size_type
unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::max_bucket_count() const
                                                          BSLS_KEYWORD_NOEXCEPT
{
    return d_impl.maxNumBuckets();
}

template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
inline
typename unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::size_type
unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::bucket_size(size_type index) const
{
    BSLS_ASSERT_SAFE(index < this->bucket_count());

    return d_impl.countElementsInBucket(index);
}

template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
inline
typename unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::size_type
unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::bucket(const key_type& key) const
{
    BSLS_ASSERT_SAFE(this->bucket_count() > 0);

    return d_impl.bucketIndexForKey(key);
}

template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
inline
typename unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::const_local_iterator
unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::begin(size_type index) const
{
    BSLS_ASSERT_SAFE(index < this->bucket_count());

    return const_local_iterator(&d_impl.bucketAtIndex(index));
}

template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
inline
typename unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::const_local_iterator
unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::end(size_type index) const
{
    BSLS_ASSERT_SAFE(index < this->bucket_count());

    return const_local_iterator(0, &d_impl.bucketAtIndex(index));
}

template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
inline
typename unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::const_local_iterator
unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::cbegin(size_type index) const
{
    BSLS_ASSERT_SAFE(index < this->bucket_count());

    return const_local_iterator(&d_impl.bucketAtIndex(index));
}

template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
inline
typename unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::const_local_iterator
unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::cend(size_type index) const
{
    BSLS_ASSERT_SAFE(index < this->bucket_count());

    return const_local_iterator(0, &d_impl.bucketAtIndex(index));
}

template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
inline
float unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::load_factor() const
                                                          BSLS_KEYWORD_NOEXCEPT
{
    return d_impl.loadFactor();
}

template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
inline
float unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::max_load_factor() const
                                                          BSLS_KEYWORD_NOEXCEPT
{
    return d_impl.maxLoadFactor();
}

}  // close namespace bsl

// FREE OPERATORS
template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
inline
bool bsl::operator==(
                    const bsl::unordered_set<KEY, HASH, EQUAL, ALLOCATOR>& lhs,
                    const bsl::unordered_set<KEY, HASH, EQUAL, ALLOCATOR>& rhs)
{
    return lhs.d_impl == rhs.d_impl;
}

#ifndef BSLS_COMPILERFEATURES_SUPPORT_THREE_WAY_COMPARISON
template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
inline
bool bsl::operator!=(
                    const bsl::unordered_set<KEY, HASH, EQUAL, ALLOCATOR>& lhs,
                    const bsl::unordered_set<KEY, HASH, EQUAL, ALLOCATOR>& rhs)
{
    return !(lhs == rhs);
}
#endif

// FREE FUNCTIONS
template <class KEY, class HASH, class EQUAL, class ALLOCATOR, class PREDICATE>
inline
typename bsl::unordered_set<KEY, HASH, EQUAL, ALLOCATOR>::size_type
bsl::erase_if(unordered_set<KEY, HASH, EQUAL, ALLOCATOR>& s,
              PREDICATE                                   predicate)
{
    return BloombergLP::bslstl::AlgorithmUtil::containerEraseIf(s, predicate);
}

template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
inline
void bsl::swap(bsl::unordered_set<KEY, HASH, EQUAL, ALLOCATOR>& a,
               bsl::unordered_set<KEY, HASH, EQUAL, ALLOCATOR>& b)
                                 BSLS_KEYWORD_NOEXCEPT_SPECIFICATION(
                                     BSLS_KEYWORD_NOEXCEPT_OPERATOR(a.swap(b)))
{
    a.swap(b);
}

// ============================================================================
//                                TYPE TRAITS
// ============================================================================

// Type traits for STL *unordered* *associative* containers:
//: o An unordered associative container defines STL iterators.
//: o An unordered associative container is bitwise movable if both functors
//:   and the allocator are bitwise movable.
//: o An unordered associative container uses 'bslma' allocators if the
//:   (template parameter) type 'ALLOCATOR' is convertible from
//:   'bslma::Allocator *'.

namespace BloombergLP {

namespace bslalg {

template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
struct HasStlIterators<bsl::unordered_set<KEY, HASH, EQUAL, ALLOCATOR> >
     : bsl::true_type
{};

}  // close namespace bslalg

namespace bslma {

template <class KEY, class HASH, class EQUAL, class ALLOCATOR>
struct UsesBslmaAllocator<bsl::unordered_set<KEY, HASH, EQUAL, ALLOCATOR> >
     : bsl::is_convertible<Allocator*, ALLOCATOR>::type
{};

}  // close namespace bslma

}  // close enterprise namespace

#else // if ! defined(DEFINED_BSLSTL_UNORDEREDSET_H)
# error Not valid except when included from bslstl_unorderedset.h
#endif // ! defined(COMPILING_BSLSTL_UNORDEREDSET_H)

#endif // ! defined(INCLUDED_BSLSTL_UNORDEREDSET_CPP03)

// ----------------------------------------------------------------------------
// Copyright 2013 Bloomberg Finance L.P.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// ----------------------------- END-OF-FILE ----------------------------------
