From 26e8b5e45903a4ed0bc667947e22d7ae0e7d5b3f Mon Sep 17 00:00:00 2001
From: Nikita Kniazev <nok.raven@gmail.com>
Date: Wed, 10 Oct 2018 01:53:34 +0300
Subject: [PATCH] vector: Simplify assign_sequence

---
 .../boost/fusion/container/vector/vector.hpp  | 21 ++++++-------------
 1 file changed, 6 insertions(+), 15 deletions(-)

diff --git a/include/boost/fusion/container/vector/vector.hpp b/include/boost/fusion/container/vector/vector.hpp
index 4993e2eb..abe2d7bb 100644
--- a/include/boost/fusion/container/vector/vector.hpp
+++ b/include/boost/fusion/container/vector/vector.hpp
@@ -214,21 +214,12 @@ namespace boost { namespace fusion
             void
             assign_sequence(Sequence&& seq)
             {
-                assign(std::forward<Sequence>(seq), detail::index_sequence<I...>());
-            }
-
-            template <typename Sequence>
-            BOOST_CXX14_CONSTEXPR BOOST_FUSION_GPU_ENABLED
-            void
-            assign(Sequence&&, detail::index_sequence<>) {}
-
-            template <typename Sequence, std::size_t N, std::size_t ...M>
-            BOOST_CXX14_CONSTEXPR BOOST_FUSION_GPU_ENABLED
-            void
-            assign(Sequence&& seq, detail::index_sequence<N, M...>)
-            {
-                at_impl(mpl::int_<N>()) = vector_detail::forward_at_c<N>(seq);
-                assign(std::forward<Sequence>(seq), detail::index_sequence<M...>());
+#ifndef BOOST_NO_CXX17_FOLD_EXPRESSIONS
+                (void(store<I, T>::elem = vector_detail::forward_at_c<I>(static_cast<Sequence&&>(seq))), ...);
+#else
+                int nofold[] = { (void(store<I, T>::elem = vector_detail::forward_at_c<I>(static_cast<Sequence&&>(seq))), 0)..., 0 };
+                (void)nofold;
+#endif
             }
 
             template <std::size_t N, typename U>