From 01f01c3ecf142b088a2181f6edc1bc631340d8cd Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E5=88=BA=E5=8F=B2=E8=89=B2=E7=AC=9B?=
 <48883004+cishisedis@users.noreply.github.com>
Date: Tue, 26 Mar 2019 12:19:35 +0100
Subject: [PATCH] simpler type signature for as_if::operator ()

---
 include/yaml-cpp/node/impl.h | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/include/yaml-cpp/node/impl.h b/include/yaml-cpp/node/impl.h
index e3e086d..1170def 100644
--- a/include/yaml-cpp/node/impl.h
+++ b/include/yaml-cpp/node/impl.h
@@ -13,7 +13,6 @@
 #include "yaml-cpp/node/iterator.h"
 #include "yaml-cpp/node/node.h"
 #include <string>
-#include <tuple>
 
 #ifdef __cpp_lib_optional
 #include <optional>
@@ -121,7 +120,7 @@ struct as_if<T, void> {
   const Node& node;
 
   template <typename U = T>
-  auto operator()() const -> typename std::tuple_element<1, std::tuple<decltype(&convert<U>::decode), T>>::type {
+  auto operator()() const -> typename std::pair<decltype(&convert<U>::decode), T>::second_type {
     if (!node.m_pNode)
       throw TypedBadConversion<T>(node.Mark());
 
@@ -133,7 +132,7 @@ struct as_if<T, void> {
 
 #ifdef __cpp_lib_optional
   template <typename U = T>
-  auto operator()() const -> typename std::tuple_element<1, std::tuple<decltype(&convert<U>::decode_optional), T>>::type {
+  auto operator()() const -> typename std::pair<decltype(&convert<U>::decode_optional), T>::second_type {
     if (!node.m_pNode)
       throw TypedBadConversion<T>(node.Mark());