Fix piecewise_construct pair constructor for compilers with variadics and constructor forwarding. Current code unconditionally moves instead of forwarding.

include/boost/container/detail/pair.hpp

@@ -214,10 +214,10 @@ struct pair
    #if !defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES)
    #  if !defined(BOOST_CONTAINER_NO_CXX11_DELEGATING_CONSTRUCTORS)
       private:
-      template<class Tuple1, class Tuple2, size_t... Indexes1, size_t... Indexes2>
-      pair(Tuple1& t1, Tuple2& t2, index_tuple<Indexes1...>, index_tuple<Indexes2...>)
-         : first (get<Indexes1>(::boost::move(t1))...)
-         , second(get<Indexes2>(::boost::move(t2))...)
+      template<template<class ...> class Tuple, class... Args1, class... Args2, size_t... Indexes1, size_t... Indexes2>
+      pair(Tuple<Args1...>& t1, Tuple<Args2...>& t2, index_tuple<Indexes1...>, index_tuple<Indexes2...>)
+         : first (::boost::forward<Args1>(get<Indexes1>(t1))...)
+         , second(::boost::forward<Args2>(get<Indexes2>(t2))...)
       {  (void) t1; (void)t2; }
 
       public:

include/boost/container/detail/variadic_templates_tools.hpp

@@ -42,13 +42,13 @@ class tuple<Head, Tail...>
    typedef tuple<Tail...> inherited;
 
    public:
-   tuple() { }
+   tuple()
+      : inherited(), m_head()
+   {}
 
-   // implicit copy-constructor is okay
-   // Construct tuple from separate arguments.
-   tuple(typename add_const_reference<Head>::type v,
-         typename add_const_reference<Tail>::type... vtail)
-   : inherited(vtail...), m_head(v)
+   template<class U, class ...Args>
+   tuple(U &&u, Args && ...args)
+      : inherited(::boost::forward<Args>(args)...), m_head(::boost::forward<U>(u))
    {}
 
    // Construct tuple from another tuple.
@@ -77,8 +77,8 @@ class tuple<Head, Tail...>
 
 
 template<typename... Values>
-tuple<Values&&...> tie_forward(Values&&... values)
-{ return tuple<Values&&...>(values...); }
+tuple<Values&&...> forward_as_tuple(Values&&... values)
+{ return tuple<Values&&...>(::boost::forward<Values>(values)...); }
 
 template<int I, typename Tuple>
 struct tuple_element;