diff --git a/Lib/test/test_descr.py b/Lib/test/test_descr.py
index 82a48ad4d1a..ab05112f1fd 100644
--- a/Lib/test/test_descr.py
+++ b/Lib/test/test_descr.py
@@ -2173,12 +2173,6 @@ class ClassPropertiesAndMethods(unittest.TestCase):
             return 1j
         def stop(self):
             raise StopIteration
-        def return_true(self, thing=None):
-            return True
-        def do_isinstance(obj):
-            return isinstance(int, obj)
-        def do_issubclass(obj):
-            return issubclass(int, obj)
         def do_dict_missing(checker):
             class DictSub(checker.__class__, dict):
                 pass
@@ -2199,11 +2193,8 @@ class ClassPropertiesAndMethods(unittest.TestCase):
             ("__length_hint__", list, zero, set(),
              {"__iter__" : iden, "__next__" : stop}),
             ("__sizeof__", sys.getsizeof, zero, set(), {}),
-            ("__instancecheck__", do_isinstance, return_true, set(), {}),
             ("__missing__", do_dict_missing, some_number,
              set(("__class__",)), {}),
-            ("__subclasscheck__", do_issubclass, return_true,
-             set(("__bases__",)), {}),
             ("__enter__", run_context, iden, set(), {"__exit__" : swallow}),
             ("__exit__", run_context, swallow, set(), {"__enter__" : iden}),
             ("__complex__", complex, complex_num, set(), {}),
diff --git a/Objects/abstract.c b/Objects/abstract.c
index f2c7de3d1ef..290ba1b801d 100644
--- a/Objects/abstract.c
+++ b/Objects/abstract.c
@@ -2691,9 +2691,6 @@ object_recursive_isinstance(PyThreadState *tstate, PyObject *inst, PyObject *cls
 
         return ok;
     }
-    else if (_PyErr_Occurred(tstate)) {
-        return -1;
-    }
 
     /* cls has no __instancecheck__() method */
     return object_isinstance(inst, cls);
@@ -2779,9 +2776,6 @@ object_issubclass(PyThreadState *tstate, PyObject *derived, PyObject *cls)
         }
         return ok;
     }
-    else if (_PyErr_Occurred(tstate)) {
-        return -1;
-    }
 
     /* Can be reached when infinite recursion happens. */
     return recursive_issubclass(derived, cls);
diff --git a/Objects/genericaliasobject.c b/Objects/genericaliasobject.c
index 8b526f43f1e..2c4c8f5eb73 100644
--- a/Objects/genericaliasobject.c
+++ b/Objects/genericaliasobject.c
@@ -654,6 +654,8 @@ static const char* const attr_exceptions[] = {
     "__parameters__",
     "__typing_unpacked_tuple_args__",
     "__mro_entries__",
+    "__instancecheck__",
+    "__subclasscheck__",
     "__reduce_ex__",  // needed so we don't look up object.__reduce_ex__
     "__reduce__",
     NULL,