Simpler fix for the regression introduced in pybind#5381

include/pybind11/cast.h

@@ -1569,10 +1569,16 @@ template <typename... Args>
 class argument_loader {
     using indices = make_index_sequence<sizeof...(Args)>;
 
+    // See PR #5396 for the discussion that led to using
+    //   any_of<std::is_same<...>, std::is_base_of<...>>
+    // instead of simply
+    //   std::is_base_of<...>
     template <typename Arg>
-    using argument_is_args = std::is_base_of<args, intrinsic_t<Arg>>;
+    using argument_is_args = any_of<
+        std::is_same<intrinsic_t<Arg>, args>, std::is_base_of<args, intrinsic_t<Arg>>>;
     template <typename Arg>
-    using argument_is_kwargs = std::is_base_of<kwargs, intrinsic_t<Arg>>;
+    using argument_is_kwargs = any_of<
+        std::is_same<intrinsic_t<Arg>, kwargs>, std::is_base_of<kwargs, intrinsic_t<Arg>>>;
     // Get kwargs argument position, or -1 if not present:
     static constexpr auto kwargs_pos = constexpr_last<argument_is_kwargs, Args...>();