From 372a47a7fabfa342a6e30345550b966e42370200 Mon Sep 17 00:00:00 2001
From: Florian Albrechtskirchinger <falbrechtskirchinger@gmail.com>
Date: Sat, 23 Jul 2022 22:09:51 +0200
Subject: [PATCH] Re-add value_type detection to is_constructible_string_type
 trait

---
 include/nlohmann/detail/meta/type_traits.hpp | 6 ++++--
 single_include/nlohmann/json.hpp             | 6 ++++--
 2 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/include/nlohmann/detail/meta/type_traits.hpp b/include/nlohmann/detail/meta/type_traits.hpp
index 11bf3c12a..796d5b0cd 100644
--- a/include/nlohmann/detail/meta/type_traits.hpp
+++ b/include/nlohmann/detail/meta/type_traits.hpp
@@ -363,8 +363,10 @@ struct is_constructible_string_type
 #endif
 
     static constexpr auto value =
-        is_constructible<laundered_type,
-        typename BasicJsonType::string_t>::value;
+        conjunction <
+        is_constructible<laundered_type, typename BasicJsonType::string_t>,
+        is_detected_exact<typename BasicJsonType::string_t::value_type,
+        value_type_t, laundered_type >>::value;
 };
 
 template<typename BasicJsonType, typename CompatibleArrayType, typename = void>
diff --git a/single_include/nlohmann/json.hpp b/single_include/nlohmann/json.hpp
index dd9c39fb5..859fdd552 100644
--- a/single_include/nlohmann/json.hpp
+++ b/single_include/nlohmann/json.hpp
@@ -3651,8 +3651,10 @@ struct is_constructible_string_type
 #endif
 
     static constexpr auto value =
-        is_constructible<laundered_type,
-        typename BasicJsonType::string_t>::value;
+        conjunction <
+        is_constructible<laundered_type, typename BasicJsonType::string_t>,
+        is_detected_exact<typename BasicJsonType::string_t::value_type,
+        value_type_t, laundered_type >>::value;
 };
 
 template<typename BasicJsonType, typename CompatibleArrayType, typename = void>