diff --git a/include/pybind11/cast.h b/include/pybind11/cast.h
index 3a3a0c964..541b71d25 100644
--- a/include/pybind11/cast.h
+++ b/include/pybind11/cast.h
@@ -919,6 +919,11 @@ public:
 
 protected:
     friend class type_caster_generic;
+    void check_holder_compat() {
+        if (typeinfo->default_holder) {
+            throw cast_error("Unable to load a custom holder type from a default-holder instance");
+        }
+    }
 
     void load_value(value_and_holder &&v_h) {
         if (typeinfo->holder_enum_v == detail::holder_enum_t::smart_holder) {
diff --git a/tests/test_smart_ptr.py b/tests/test_smart_ptr.py
index 0d1961999..bf0ae4aeb 100644
--- a/tests/test_smart_ptr.py
+++ b/tests/test_smart_ptr.py
@@ -298,7 +298,6 @@ def test_move_only_holder_with_addressof_operator():
 
 
 def test_smart_ptr_from_default():
-    pytest.skip("BAKEIN_EXPECTED: Failed: DID NOT RAISE <class 'RuntimeError'>")
     instance = m.HeldByDefaultHolder()
     with pytest.raises(RuntimeError) as excinfo:
         m.HeldByDefaultHolder.load_shared_ptr(instance)