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diff --git a/boost/hof/alias.hpp b/boost/hof/alias.hpp
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+/*=============================================================================
+    Copyright (c) 2015 Paul Fultz II
+    alias.h
+    Distributed under the Boost Software License, Version 1.0. (See accompanying
+    file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+==============================================================================*/
+
+#ifndef BOOST_HOF_GUARD_ALIAS_H
+#define BOOST_HOF_GUARD_ALIAS_H
+
+#include <boost/hof/returns.hpp>
+#include <boost/hof/detail/delegate.hpp>
+#include <boost/hof/detail/move.hpp>
+#include <boost/hof/detail/holder.hpp>
+#include <boost/hof/config.hpp>
+
+/// alias
+/// =====
+/// 
+/// Description
+/// -----------
+/// 
+/// The `alias` class wraps a type with a new type that can be tagged by the
+/// user. This allows defining extra attributes about the type outside of the
+/// type itself. There are three different ways the value can be stored: as a
+/// member variable, by inheritance, or as a static member variable. The value
+/// can be retrieved uniformily using the `alias_value` function.
+/// 
+/// Synopsis
+/// --------
+/// 
+///     // Alias the type using a member variable
+///     template<class T, class Tag=void>
+///     class alias;
+/// 
+///     // Alias the type by inheriting
+///     template<class T, class Tag=void>
+///     class alias_inherit;
+/// 
+///     // Alias the type using a static variable
+///     template<class T, class Tag=void>
+///     class alias_static;
+/// 
+///     // Retrieve tag from alias
+///     template<class Alias>
+///     class alias_tag;
+/// 
+///     // Check if type has a certian tag
+///     template<class T, class Tag>
+///     class has_tag;
+/// 
+///     // Retrieve value from alias
+///     template<class Alias>
+///     constexpr auto alias_value(Alias&&);
+/// 
+
+#ifdef _MSC_VER
+#pragma warning(push)
+#pragma warning(disable: 4579)
+#endif
+
+namespace boost { namespace hof {
+
+template<class T>
+struct alias_tag;
+
+template<class T, class Tag, class=void>
+struct has_tag
+: std::false_type
+{};
+
+template<class T, class Tag>
+struct has_tag<T, Tag, typename detail::holder<
+    typename alias_tag<T>::type
+>::type>
+: std::is_same<typename alias_tag<T>::type, Tag>
+{};
+
+namespace detail {
+
+template<class T>
+constexpr T& lvalue(T& x) noexcept
+{
+    return x;
+}
+
+template<class T>
+constexpr const T& lvalue(const T& x) noexcept
+{
+    return x;
+}
+
+}
+
+#define BOOST_HOF_UNARY_PERFECT_FOREACH(m) \
+    m(const&, boost::hof::detail::lvalue) \
+    m(&, boost::hof::detail::lvalue) \
+    m(&&, boost::hof::move) \
+
+template<class T, class Tag=void>
+struct alias
+{
+    T value;
+    BOOST_HOF_DELEGATE_CONSTRUCTOR(alias, T, value)
+};
+
+#define BOOST_HOF_DETAIL_ALIAS_GET_VALUE(ref, move) \
+template<class Tag, class T, class... Ts> \
+constexpr auto alias_value(alias<T, Tag> ref a, Ts&&...) BOOST_HOF_RETURNS(move(a.value))
+BOOST_HOF_UNARY_PERFECT_FOREACH(BOOST_HOF_DETAIL_ALIAS_GET_VALUE)
+
+template<class T, class Tag>
+struct alias_tag<alias<T, Tag>>
+{ typedef Tag type; };
+
+
+template<class T, class Tag=void>
+struct alias_inherit 
+#if (defined(__GNUC__) && !defined (__clang__))
+: std::conditional<(std::is_class<T>::value), T, alias<T>>::type
+#else
+: T
+#endif
+{
+    BOOST_HOF_INHERIT_CONSTRUCTOR(alias_inherit, T)
+};
+
+#define BOOST_HOF_DETAIL_ALIAS_INHERIT_GET_VALUE(ref, move) \
+template<class Tag, class T, class... Ts, class=typename std::enable_if<(BOOST_HOF_IS_CLASS(T))>::type> \
+constexpr T ref alias_value(alias_inherit<T, Tag> ref a, Ts&&...) BOOST_HOF_RETURNS_DEDUCE_NOEXCEPT(move(a)) \
+{ \
+    return move(a); \
+}
+BOOST_HOF_UNARY_PERFECT_FOREACH(BOOST_HOF_DETAIL_ALIAS_INHERIT_GET_VALUE)
+
+template<class T, class Tag>
+struct alias_tag<alias_inherit<T, Tag>>
+{ typedef Tag type; };
+
+namespace detail {
+
+template<class T, class Tag>
+struct alias_static_storage
+{
+#ifdef _MSC_VER
+    // Since we disable the error for 4579 on MSVC, which leaves the static
+    // member unitialized at runtime, it is, therefore, only safe to use this
+    // class on types that are empty with constructors that have no possible
+    // side effects.
+    static_assert(BOOST_HOF_IS_EMPTY(T) && 
+        BOOST_HOF_IS_LITERAL(T) && 
+        BOOST_HOF_IS_DEFAULT_CONSTRUCTIBLE(T), "In-class initialization is not yet implemented on MSVC");
+#endif
+    static constexpr T value = T();
+};
+
+template<class T, class Tag>
+constexpr T alias_static_storage<T, Tag>::value;
+
+}
+
+template<class T, class Tag=void>
+struct alias_static
+{
+    template<class... Ts, BOOST_HOF_ENABLE_IF_CONSTRUCTIBLE(T, Ts...)>
+    constexpr alias_static(Ts&&...) noexcept
+    {}
+};
+
+template<class Tag, class T, class... Ts>
+constexpr const T& alias_value(const alias_static<T, Tag>&, Ts&&...) noexcept
+{
+    return detail::alias_static_storage<T, Tag>::value;
+}
+
+template<class T, class Tag>
+struct alias_tag<alias_static<T, Tag>>
+{ typedef Tag type; };
+
+namespace detail {
+
+template<class T, class Tag>
+struct alias_try_inherit
+: std::conditional<(BOOST_HOF_IS_CLASS(T) && !BOOST_HOF_IS_FINAL(T) && !BOOST_HOF_IS_POLYMORPHIC(T)), 
+    alias_inherit<T, Tag>, 
+    alias<T, Tag>
+>
+{};
+
+#if BOOST_HOF_HAS_EBO
+template<class T, class Tag>
+struct alias_empty
+: std::conditional<(BOOST_HOF_IS_EMPTY(T)), 
+    typename alias_try_inherit<T, Tag>::type, 
+    alias<T, Tag>
+>
+{};
+#else
+template<class T, class Tag>
+struct alias_empty
+: std::conditional<
+        BOOST_HOF_IS_EMPTY(T) && 
+        BOOST_HOF_IS_LITERAL(T) && 
+        BOOST_HOF_IS_DEFAULT_CONSTRUCTIBLE(T),
+    alias_static<T, Tag>,
+    alias<T, Tag>
+>
+{};
+#endif
+
+}
+
+}} // namespace boost::hof
+
+#ifdef _MSC_VER
+#pragma warning(pop)
+#endif
+
+#endif