From bb1b4c934e728e9bedaa6d3a97f90807a2857fcd Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Th=C3=A9o=20DELRIEU?= <delrieutheo@gmail.com>
Date: Tue, 22 Aug 2017 23:40:10 +0200
Subject: [PATCH] fix from_json implementation for pair/tuple

Introduced by 6e4910d5c5638bedbc3ff650d1b6b91249a927a3

Fixes #707
---
 src/json.hpp                   | 8 ++++----
 test/src/unit-constructor1.cpp | 4 +++-
 2 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/src/json.hpp b/src/json.hpp
index 83c9ef2e5..ef55a93ce 100644
--- a/src/json.hpp
+++ b/src/json.hpp
@@ -1235,16 +1235,16 @@ void from_json(const BasicJsonType& j, ArithmeticType& val)
     }
 }
 
-template<typename BasicJsonType, typename... Args>
-void from_json(const BasicJsonType& j, std::pair<Args...>& p)
+template<typename BasicJsonType, typename A1, typename A2>
+void from_json(const BasicJsonType& j, std::pair<A1, A2>& p)
 {
-    p = {j.at(0), j.at(1)};
+    p = {j.at(0).template get<A1>(), j.at(1).template get<A2>()};
 }
 
 template<typename BasicJsonType, typename Tuple, std::size_t... Idx>
 void from_json_tuple_impl(const BasicJsonType& j, Tuple& t, index_sequence<Idx...>)
 {
-    t = std::make_tuple(j.at(Idx)...);
+    t = std::make_tuple(j.at(Idx).template get<typename std::tuple_element<Idx, Tuple>::type>()...);
 }
 
 template<typename BasicJsonType, typename... Args>
diff --git a/test/src/unit-constructor1.cpp b/test/src/unit-constructor1.cpp
index da10ed2e1..10b5216dd 100644
--- a/test/src/unit-constructor1.cpp
+++ b/test/src/unit-constructor1.cpp
@@ -246,6 +246,7 @@ TEST_CASE("constructors")
             json j(p);
 
             CHECK(j.type() == json::value_t::array);
+            CHECK(j.get<decltype(p)>() == p);
             REQUIRE(j.size() == 2);
             CHECK(j[0] == std::get<0>(p));
             CHECK(j[1] == std::get<1>(p));
@@ -262,11 +263,12 @@ TEST_CASE("constructors")
 
         SECTION("std::tuple")
         {
-            const auto t = std::make_tuple(1.0, "string", 42, std::vector<int> {0, 1});
+            const auto t = std::make_tuple(1.0, std::string{"string"}, 42, std::vector<int> {0, 1});
             json j(t);
 
             CHECK(j.type() == json::value_t::array);
             REQUIRE(j.size() == 4);
+            CHECK(j.get<decltype(t)>() == t);
             CHECK(j[0] == std::get<0>(t));
             CHECK(j[1] == std::get<1>(t));
             CHECK(j[2] == std::get<2>(t));