diff options
Diffstat (limited to 'Lib/typing.py')
| -rw-r--r-- | Lib/typing.py | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/Lib/typing.py b/Lib/typing.py index 423329a..4c2d9fc 100644 --- a/Lib/typing.py +++ b/Lib/typing.py @@ -1081,6 +1081,9 @@ class _GenericAlias(_BaseGenericAlias, _root=True): return operator.getitem, (origin, args) def __mro_entries__(self, bases): + if isinstance(self.__origin__, _SpecialForm): + raise TypeError(f"Cannot subclass {self!r}") + if self._name: # generic version of an ABC or built-in class return super().__mro_entries__(bases) if self.__origin__ is Generic: |