From 5affe7c73658514dccafd622e30d4fc1ec68b2ef Mon Sep 17 00:00:00 2001
From: Simon Brand <tartanllama@gmail.com>
Date: Sat, 21 Oct 2017 20:57:56 +0100
Subject: [PATCH] Deduction guide

---
 optional.hpp | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/optional.hpp b/optional.hpp
index f3c9f8e..f243fba 100644
--- a/optional.hpp
+++ b/optional.hpp
@@ -1346,7 +1346,10 @@ inline constexpr optional<T> make_optional(std::initializer_list<U> il,
   return optional<T>(in_place, il, std::forward<Args>(args)...);
 }
 
-// template <class T> optional(T)->optional<T>;
+#if __cplusplus >= 201703L
+template <class T> optional(T)->optional<T>;
+#endif
+
 } // namespace tl
 
 namespace std {