diff --git a/include/nlohmann/json.hpp b/include/nlohmann/json.hpp
index 8e2de8375f..053be8f744 100644
--- a/include/nlohmann/json.hpp
+++ b/include/nlohmann/json.hpp
@@ -6072,6 +6072,9 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
         for (auto it = first; it != last; ++it)
         {
             m_value.object->operator[](it.key()) = it.value();
+#if JSON_DIAGNOSTICS
+            m_value.object->operator[](it.key()).m_parent = this;
+#endif
         }
     }
 
diff --git a/single_include/nlohmann/json.hpp b/single_include/nlohmann/json.hpp
index 4bae31ac90..803a83c394 100644
--- a/single_include/nlohmann/json.hpp
+++ b/single_include/nlohmann/json.hpp
@@ -23477,6 +23477,9 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
         for (auto it = first; it != last; ++it)
         {
             m_value.object->operator[](it.key()) = it.value();
+#if JSON_DIAGNOSTICS
+            m_value.object->operator[](it.key()).m_parent = this;
+#endif
         }
     }