From 307b828ed510f286852848ccf94c186e038cc928 Mon Sep 17 00:00:00 2001
From: Florian Albrechtskirchinger <falbrechtskirchinger@gmail.com>
Date: Sun, 24 Jul 2022 07:35:40 +0200
Subject: [PATCH] Add value_type detection to from_json for strings

---
 include/nlohmann/detail/conversions/from_json.hpp | 1 +
 single_include/nlohmann/json.hpp                  | 1 +
 2 files changed, 2 insertions(+)

diff --git a/include/nlohmann/detail/conversions/from_json.hpp b/include/nlohmann/detail/conversions/from_json.hpp
index f1df783e51..af2abddbf0 100644
--- a/include/nlohmann/detail/conversions/from_json.hpp
+++ b/include/nlohmann/detail/conversions/from_json.hpp
@@ -117,6 +117,7 @@ template <
     typename BasicJsonType, typename StringType,
     enable_if_t <
         std::is_assignable<StringType&, const typename BasicJsonType::string_t>::value
+        && is_detected_exact<typename BasicJsonType::string_t::value_type, value_type_t, StringType>::value
         && !std::is_same<typename BasicJsonType::string_t, StringType>::value
         && !is_json_ref<StringType>::value, int > = 0 >
 inline void from_json(const BasicJsonType& j, StringType& s)
diff --git a/single_include/nlohmann/json.hpp b/single_include/nlohmann/json.hpp
index 859fdd5528..e9a451eacf 100644
--- a/single_include/nlohmann/json.hpp
+++ b/single_include/nlohmann/json.hpp
@@ -4480,6 +4480,7 @@ template <
     typename BasicJsonType, typename StringType,
     enable_if_t <
         std::is_assignable<StringType&, const typename BasicJsonType::string_t>::value
+        && is_detected_exact<typename BasicJsonType::string_t::value_type, value_type_t, StringType>::value
         && !std::is_same<typename BasicJsonType::string_t, StringType>::value
         && !is_json_ref<StringType>::value, int > = 0 >
 inline void from_json(const BasicJsonType& j, StringType& s)