diff --git a/include/nlohmann/detail/input/input_adapters.hpp b/include/nlohmann/detail/input/input_adapters.hpp
index 3d90ac3e..725ff1fe 100644
--- a/include/nlohmann/detail/input/input_adapters.hpp
+++ b/include/nlohmann/detail/input/input_adapters.hpp
@@ -147,7 +147,7 @@ class iterator_input_adapter
     IteratorType end;
 
     template<typename BaseInputAdapter, size_t T>
-    friend class wide_string_input_helper;
+    friend struct wide_string_input_helper;
 
     bool empty() const
     {
diff --git a/single_include/nlohmann/json.hpp b/single_include/nlohmann/json.hpp
index 85e42878..0b5b2a58 100644
--- a/single_include/nlohmann/json.hpp
+++ b/single_include/nlohmann/json.hpp
@@ -4569,7 +4569,7 @@ class iterator_input_adapter
     IteratorType end;
 
     template<typename BaseInputAdapter, size_t T>
-    friend class wide_string_input_helper;
+    friend struct wide_string_input_helper;
 
     bool empty() const
     {