From 714c5926803cbf790396fee5776a8d63fe566c9b Mon Sep 17 00:00:00 2001
From: Guillaume Racicot <gufideg@gmail.com>
Date: Fri, 1 Jun 2018 14:22:57 -0400
Subject: [PATCH] Disabled implicit conversion to string_view on MSVC 15.13 and
 older

---
 include/nlohmann/json.hpp        |  4 ++--
 single_include/nlohmann/json.hpp | 13 +++----------
 test/src/unit-conversions.cpp    |  7 +++++++
 3 files changed, 12 insertions(+), 12 deletions(-)

diff --git a/include/nlohmann/json.hpp b/include/nlohmann/json.hpp
index 7ecf631f..38b31240 100644
--- a/include/nlohmann/json.hpp
+++ b/include/nlohmann/json.hpp
@@ -2821,9 +2821,9 @@ class basic_json
                    not detail::is_basic_json<ValueType>::value
 #ifndef _MSC_VER  // fix for issue #167 operator<< ambiguity under VS2015
                    and not std::is_same<ValueType, std::initializer_list<typename string_t::value_type>>::value
-#endif
-#if defined(JSON_HAS_CPP_17)
+#if defined(JSON_HAS_CPP_17) && _MSC_VER <= 1913
                    and not std::is_same<ValueType, typename std::string_view>::value
+#endif
 #endif
                    , int >::type = 0 >
     operator ValueType() const
diff --git a/single_include/nlohmann/json.hpp b/single_include/nlohmann/json.hpp
index 498ba880..2c9c94fd 100644
--- a/single_include/nlohmann/json.hpp
+++ b/single_include/nlohmann/json.hpp
@@ -1321,16 +1321,6 @@ struct external_constructor<value_t::string>
         j.m_value = std::move(s);
         j.assert_invariant();
     }
-
-    template<typename BasicJsonType, typename CompatibleStringType,
-             enable_if_t<not std::is_same<CompatibleStringType, typename BasicJsonType::string_t>::value,
-                         int> = 0>
-    static void construct(BasicJsonType& j, const CompatibleStringType& str)
-    {
-        j.m_type = value_t::string;
-        j.m_value.string = j.template create<typename BasicJsonType::string_t>(str);
-        j.assert_invariant();
-    }
 };
 
 template<>
@@ -12480,6 +12470,9 @@ class basic_json
                    not detail::is_basic_json<ValueType>::value
 #ifndef _MSC_VER  // fix for issue #167 operator<< ambiguity under VS2015
                    and not std::is_same<ValueType, std::initializer_list<typename string_t::value_type>>::value
+#if defined(JSON_HAS_CPP_17) && _MSC_VER <= 1913
+                   and not std::is_same<ValueType, typename std::string_view>::value
+#endif
 #endif
                    , int >::type = 0 >
     operator ValueType() const
diff --git a/test/src/unit-conversions.cpp b/test/src/unit-conversions.cpp
index b059087c..ef27ac6f 100644
--- a/test/src/unit-conversions.cpp
+++ b/test/src/unit-conversions.cpp
@@ -39,6 +39,13 @@ using nlohmann::json;
 #include <unordered_set>
 #include <valarray>
 
+#if (defined(__cplusplus) && __cplusplus >= 201703L) || (defined(_HAS_CXX17) && _HAS_CXX17 == 1) // fix for issue #464
+    #define JSON_HAS_CPP_17
+    #define JSON_HAS_CPP_14
+#elif (defined(__cplusplus) && __cplusplus >= 201402L) || (defined(_HAS_CXX14) && _HAS_CXX14 == 1)
+    #define JSON_HAS_CPP_14
+#endif
+
 #if defined(JSON_HAS_CPP_17)
 #include <string_view>
 #endif