diff --git a/include/nlohmann/detail/conversions/to_json.hpp b/include/nlohmann/detail/conversions/to_json.hpp
index a0ca4211a..8d1ac30c5 100644
--- a/include/nlohmann/detail/conversions/to_json.hpp
+++ b/include/nlohmann/detail/conversions/to_json.hpp
@@ -30,6 +30,7 @@ struct external_constructor<value_t::boolean>
     template<typename BasicJsonType>
     static void construct(BasicJsonType& j, typename BasicJsonType::boolean_t b) noexcept
     {
+        j.m_value.destroy(j.m_type);
         j.m_type = value_t::boolean;
         j.m_value = b;
         j.assert_invariant();
@@ -42,6 +43,7 @@ struct external_constructor<value_t::string>
     template<typename BasicJsonType>
     static void construct(BasicJsonType& j, const typename BasicJsonType::string_t& s)
     {
+        j.m_value.destroy(j.m_type);
         j.m_type = value_t::string;
         j.m_value = s;
         j.assert_invariant();
@@ -50,6 +52,7 @@ struct external_constructor<value_t::string>
     template<typename BasicJsonType>
     static void construct(BasicJsonType& j, typename BasicJsonType::string_t&& s)
     {
+        j.m_value.destroy(j.m_type);
         j.m_type = value_t::string;
         j.m_value = std::move(s);
         j.assert_invariant();
@@ -60,6 +63,7 @@ struct external_constructor<value_t::string>
                              int > = 0 >
     static void construct(BasicJsonType& j, const CompatibleStringType& str)
     {
+        j.m_value.destroy(j.m_type);
         j.m_type = value_t::string;
         j.m_value.string = j.template create<typename BasicJsonType::string_t>(str);
         j.assert_invariant();
@@ -72,6 +76,7 @@ struct external_constructor<value_t::binary>
     template<typename BasicJsonType>
     static void construct(BasicJsonType& j, const typename BasicJsonType::binary_t& b)
     {
+        j.m_value.destroy(j.m_type);
         j.m_type = value_t::binary;
         j.m_value = typename BasicJsonType::binary_t(b);
         j.assert_invariant();
@@ -80,6 +85,7 @@ struct external_constructor<value_t::binary>
     template<typename BasicJsonType>
     static void construct(BasicJsonType& j, typename BasicJsonType::binary_t&& b)
     {
+        j.m_value.destroy(j.m_type);
         j.m_type = value_t::binary;
         j.m_value = typename BasicJsonType::binary_t(std::move(b));;
         j.assert_invariant();
@@ -92,6 +98,7 @@ struct external_constructor<value_t::number_float>
     template<typename BasicJsonType>
     static void construct(BasicJsonType& j, typename BasicJsonType::number_float_t val) noexcept
     {
+        j.m_value.destroy(j.m_type);
         j.m_type = value_t::number_float;
         j.m_value = val;
         j.assert_invariant();
@@ -104,6 +111,7 @@ struct external_constructor<value_t::number_unsigned>
     template<typename BasicJsonType>
     static void construct(BasicJsonType& j, typename BasicJsonType::number_unsigned_t val) noexcept
     {
+        j.m_value.destroy(j.m_type);
         j.m_type = value_t::number_unsigned;
         j.m_value = val;
         j.assert_invariant();
@@ -116,6 +124,7 @@ struct external_constructor<value_t::number_integer>
     template<typename BasicJsonType>
     static void construct(BasicJsonType& j, typename BasicJsonType::number_integer_t val) noexcept
     {
+        j.m_value.destroy(j.m_type);
         j.m_type = value_t::number_integer;
         j.m_value = val;
         j.assert_invariant();
@@ -128,6 +137,7 @@ struct external_constructor<value_t::array>
     template<typename BasicJsonType>
     static void construct(BasicJsonType& j, const typename BasicJsonType::array_t& arr)
     {
+        j.m_value.destroy(j.m_type);
         j.m_type = value_t::array;
         j.m_value = arr;
         j.set_parents();
@@ -137,6 +147,7 @@ struct external_constructor<value_t::array>
     template<typename BasicJsonType>
     static void construct(BasicJsonType& j, typename BasicJsonType::array_t&& arr)
     {
+        j.m_value.destroy(j.m_type);
         j.m_type = value_t::array;
         j.m_value = std::move(arr);
         j.set_parents();
@@ -150,6 +161,8 @@ struct external_constructor<value_t::array>
     {
         using std::begin;
         using std::end;
+
+        j.m_value.destroy(j.m_type);
         j.m_type = value_t::array;
         j.m_value.array = j.template create<typename BasicJsonType::array_t>(begin(arr), end(arr));
         j.set_parents();
@@ -159,6 +172,7 @@ struct external_constructor<value_t::array>
     template<typename BasicJsonType>
     static void construct(BasicJsonType& j, const std::vector<bool>& arr)
     {
+        j.m_value.destroy(j.m_type);
         j.m_type = value_t::array;
         j.m_value = value_t::array;
         j.m_value.array->reserve(arr.size());
@@ -174,6 +188,7 @@ struct external_constructor<value_t::array>
              enable_if_t<std::is_convertible<T, BasicJsonType>::value, int> = 0>
     static void construct(BasicJsonType& j, const std::valarray<T>& arr)
     {
+        j.m_value.destroy(j.m_type);
         j.m_type = value_t::array;
         j.m_value = value_t::array;
         j.m_value.array->resize(arr.size());
@@ -192,6 +207,7 @@ struct external_constructor<value_t::object>
     template<typename BasicJsonType>
     static void construct(BasicJsonType& j, const typename BasicJsonType::object_t& obj)
     {
+        j.m_value.destroy(j.m_type);
         j.m_type = value_t::object;
         j.m_value = obj;
         j.set_parents();
@@ -201,6 +217,7 @@ struct external_constructor<value_t::object>
     template<typename BasicJsonType>
     static void construct(BasicJsonType& j, typename BasicJsonType::object_t&& obj)
     {
+        j.m_value.destroy(j.m_type);
         j.m_type = value_t::object;
         j.m_value = std::move(obj);
         j.set_parents();
@@ -214,6 +231,7 @@ struct external_constructor<value_t::object>
         using std::begin;
         using std::end;
 
+        j.m_value.destroy(j.m_type);
         j.m_type = value_t::object;
         j.m_value.object = j.template create<typename BasicJsonType::object_t>(begin(obj), end(obj));
         j.set_parents();
@@ -236,10 +254,6 @@ template<typename BasicJsonType, typename CompatibleString,
          enable_if_t<std::is_constructible<typename BasicJsonType::string_t, CompatibleString>::value, int> = 0>
 void to_json(BasicJsonType& j, const CompatibleString& s)
 {
-    if (!j.is_null())
-    {
-        j = BasicJsonType();
-    }
     external_constructor<value_t::string>::construct(j, s);
 }
 
diff --git a/single_include/nlohmann/json.hpp b/single_include/nlohmann/json.hpp
index 4bdadd871..32cacdbcd 100644
--- a/single_include/nlohmann/json.hpp
+++ b/single_include/nlohmann/json.hpp
@@ -4488,6 +4488,7 @@ struct external_constructor<value_t::boolean>
     template<typename BasicJsonType>
     static void construct(BasicJsonType& j, typename BasicJsonType::boolean_t b) noexcept
     {
+        j.m_value.destroy(j.m_type);
         j.m_type = value_t::boolean;
         j.m_value = b;
         j.assert_invariant();
@@ -4500,6 +4501,7 @@ struct external_constructor<value_t::string>
     template<typename BasicJsonType>
     static void construct(BasicJsonType& j, const typename BasicJsonType::string_t& s)
     {
+        j.m_value.destroy(j.m_type);
         j.m_type = value_t::string;
         j.m_value = s;
         j.assert_invariant();
@@ -4508,6 +4510,7 @@ struct external_constructor<value_t::string>
     template<typename BasicJsonType>
     static void construct(BasicJsonType& j, typename BasicJsonType::string_t&& s)
     {
+        j.m_value.destroy(j.m_type);
         j.m_type = value_t::string;
         j.m_value = std::move(s);
         j.assert_invariant();
@@ -4518,6 +4521,7 @@ struct external_constructor<value_t::string>
                              int > = 0 >
     static void construct(BasicJsonType& j, const CompatibleStringType& str)
     {
+        j.m_value.destroy(j.m_type);
         j.m_type = value_t::string;
         j.m_value.string = j.template create<typename BasicJsonType::string_t>(str);
         j.assert_invariant();
@@ -4530,6 +4534,7 @@ struct external_constructor<value_t::binary>
     template<typename BasicJsonType>
     static void construct(BasicJsonType& j, const typename BasicJsonType::binary_t& b)
     {
+        j.m_value.destroy(j.m_type);
         j.m_type = value_t::binary;
         j.m_value = typename BasicJsonType::binary_t(b);
         j.assert_invariant();
@@ -4538,6 +4543,7 @@ struct external_constructor<value_t::binary>
     template<typename BasicJsonType>
     static void construct(BasicJsonType& j, typename BasicJsonType::binary_t&& b)
     {
+        j.m_value.destroy(j.m_type);
         j.m_type = value_t::binary;
         j.m_value = typename BasicJsonType::binary_t(std::move(b));;
         j.assert_invariant();
@@ -4550,6 +4556,7 @@ struct external_constructor<value_t::number_float>
     template<typename BasicJsonType>
     static void construct(BasicJsonType& j, typename BasicJsonType::number_float_t val) noexcept
     {
+        j.m_value.destroy(j.m_type);
         j.m_type = value_t::number_float;
         j.m_value = val;
         j.assert_invariant();
@@ -4562,6 +4569,7 @@ struct external_constructor<value_t::number_unsigned>
     template<typename BasicJsonType>
     static void construct(BasicJsonType& j, typename BasicJsonType::number_unsigned_t val) noexcept
     {
+        j.m_value.destroy(j.m_type);
         j.m_type = value_t::number_unsigned;
         j.m_value = val;
         j.assert_invariant();
@@ -4574,6 +4582,7 @@ struct external_constructor<value_t::number_integer>
     template<typename BasicJsonType>
     static void construct(BasicJsonType& j, typename BasicJsonType::number_integer_t val) noexcept
     {
+        j.m_value.destroy(j.m_type);
         j.m_type = value_t::number_integer;
         j.m_value = val;
         j.assert_invariant();
@@ -4586,6 +4595,7 @@ struct external_constructor<value_t::array>
     template<typename BasicJsonType>
     static void construct(BasicJsonType& j, const typename BasicJsonType::array_t& arr)
     {
+        j.m_value.destroy(j.m_type);
         j.m_type = value_t::array;
         j.m_value = arr;
         j.set_parents();
@@ -4595,6 +4605,7 @@ struct external_constructor<value_t::array>
     template<typename BasicJsonType>
     static void construct(BasicJsonType& j, typename BasicJsonType::array_t&& arr)
     {
+        j.m_value.destroy(j.m_type);
         j.m_type = value_t::array;
         j.m_value = std::move(arr);
         j.set_parents();
@@ -4608,6 +4619,8 @@ struct external_constructor<value_t::array>
     {
         using std::begin;
         using std::end;
+
+        j.m_value.destroy(j.m_type);
         j.m_type = value_t::array;
         j.m_value.array = j.template create<typename BasicJsonType::array_t>(begin(arr), end(arr));
         j.set_parents();
@@ -4617,6 +4630,7 @@ struct external_constructor<value_t::array>
     template<typename BasicJsonType>
     static void construct(BasicJsonType& j, const std::vector<bool>& arr)
     {
+        j.m_value.destroy(j.m_type);
         j.m_type = value_t::array;
         j.m_value = value_t::array;
         j.m_value.array->reserve(arr.size());
@@ -4632,6 +4646,7 @@ struct external_constructor<value_t::array>
              enable_if_t<std::is_convertible<T, BasicJsonType>::value, int> = 0>
     static void construct(BasicJsonType& j, const std::valarray<T>& arr)
     {
+        j.m_value.destroy(j.m_type);
         j.m_type = value_t::array;
         j.m_value = value_t::array;
         j.m_value.array->resize(arr.size());
@@ -4650,6 +4665,7 @@ struct external_constructor<value_t::object>
     template<typename BasicJsonType>
     static void construct(BasicJsonType& j, const typename BasicJsonType::object_t& obj)
     {
+        j.m_value.destroy(j.m_type);
         j.m_type = value_t::object;
         j.m_value = obj;
         j.set_parents();
@@ -4659,6 +4675,7 @@ struct external_constructor<value_t::object>
     template<typename BasicJsonType>
     static void construct(BasicJsonType& j, typename BasicJsonType::object_t&& obj)
     {
+        j.m_value.destroy(j.m_type);
         j.m_type = value_t::object;
         j.m_value = std::move(obj);
         j.set_parents();
@@ -4672,6 +4689,7 @@ struct external_constructor<value_t::object>
         using std::begin;
         using std::end;
 
+        j.m_value.destroy(j.m_type);
         j.m_type = value_t::object;
         j.m_value.object = j.template create<typename BasicJsonType::object_t>(begin(obj), end(obj));
         j.set_parents();
@@ -4694,10 +4712,6 @@ template<typename BasicJsonType, typename CompatibleString,
          enable_if_t<std::is_constructible<typename BasicJsonType::string_t, CompatibleString>::value, int> = 0>
 void to_json(BasicJsonType& j, const CompatibleString& s)
 {
-    if (!j.is_null())
-    {
-        j = BasicJsonType();
-    }
     external_constructor<value_t::string>::construct(j, s);
 }