bpo-46927: Include the type's name in the error message for subscripting non-generic types (GH-31694)

Author: serhiy-storchaka

Lib/test/test_exception_group.py

@@ -11,7 +11,7 @@ def test_exception_group_types(self):
         self.assertTrue(issubclass(BaseExceptionGroup, BaseException))
 
     def test_exception_is_not_generic_type(self):
-        with self.assertRaises(TypeError):
+        with self.assertRaisesRegex(TypeError, 'Exception'):
             Exception[OSError]
 
     def test_exception_group_is_generic_type(self):

Lib/test/test_genericalias.py

@@ -109,7 +109,7 @@ def test_unsubscriptable(self):
         for t in int, str, float, Sized, Hashable:
             tname = t.__name__
             with self.subTest(f"Testing {tname}"):
-                with self.assertRaises(TypeError):
+                with self.assertRaisesRegex(TypeError, tname):
                     t[int]
 
     def test_instantiate(self):
@@ -275,7 +275,7 @@ def test_type_generic(self):
     def test_type_subclass_generic(self):
         class MyType(type):
             pass
-        with self.assertRaises(TypeError):
+        with self.assertRaisesRegex(TypeError, 'MyType'):
             MyType[int]
 
     def test_pickle(self):

Misc/NEWS.d/next/Core and Builtins/2022-03-05-12-23-58.bpo-46927.URbHBi.rst

@@ -0,0 +1,2 @@
+Include the type's name in the error message for subscripting non-generic
+types.

Objects/abstract.c

@@ -190,6 +190,9 @@ PyObject_GetItem(PyObject *o, PyObject *key)
             Py_DECREF(meth);
             return result;
         }
+        PyErr_Format(PyExc_TypeError, "type '%.200s' is not subscriptable",
+                     ((PyTypeObject *)o)->tp_name);
+        return NULL;
     }
 
     return type_error("'%.200s' object is not subscriptable", o);