Re-add value_type detection to is_constructible_string_type trait

nlohmann · Jul 23, 2022 · 372a47a · 372a47a
1 parent e91686c
commit 372a47a
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Showing 2 changed files with 8 additions and 4 deletions.
diff --git 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
@@ -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>