diff options
Diffstat (limited to 'Lib/typing.py')
| -rw-r--r-- | Lib/typing.py | 32 |
1 files changed, 3 insertions, 29 deletions
diff --git a/Lib/typing.py b/Lib/typing.py index b10615c..3e82c6b 100644 --- a/Lib/typing.py +++ b/Lib/typing.py @@ -206,8 +206,8 @@ def _check_generic(cls, parameters): def _remove_dups_flatten(parameters): - """An internal helper for Union creation and substitution: flatten Union's - among parameters, then remove duplicates and strict subclasses. + """An internal helper for Union creation and substitution: flatten Unions + among parameters, then remove duplicates. """ # Flatten out Union[Union[...], ...]. params = [] @@ -228,20 +228,7 @@ def _remove_dups_flatten(parameters): all_params.remove(t) params = new_params assert not all_params, all_params - # Weed out subclasses. - # E.g. Union[int, Employee, Manager] == Union[int, Employee]. - # If object is present it will be sole survivor among proper classes. - # Never discard type variables. - # (In particular, Union[str, AnyStr] != AnyStr.) - all_params = set(params) - for t1 in params: - if not isinstance(t1, type): - continue - if any((isinstance(t2, type) or - isinstance(t2, _GenericAlias) and t2._special) and issubclass(t1, t2) - for t2 in all_params - {t1}): - all_params.remove(t1) - return tuple(t for t in params if t in all_params) + return tuple(params) _cleanups = [] @@ -440,19 +427,6 @@ Union = _SpecialForm('Union', doc= Union[int, str] == Union[str, int] - - When two arguments have a subclass relationship, the least - derived argument is kept, e.g.:: - - class Employee: pass - class Manager(Employee): pass - Union[int, Employee, Manager] == Union[int, Employee] - Union[Manager, int, Employee] == Union[int, Employee] - Union[Employee, Manager] == Employee - - - Similar for object:: - - Union[int, object] == object - - You cannot subclass or instantiate a union. - You can use Optional[X] as a shorthand for Union[X, None]. """) |