Merge pull request python#153 from o11c/typing-slots

Use `__slots__` in `typing` module.

prototyping/typing.py

@@ -128,6 +128,8 @@ def __repr__(self):
 class Final:
     """Mix-in class to prevent instantiation."""
 
+    __slots__ = ()
+
     def __new__(self, *args, **kwds):
         raise TypeError("Cannot instantiate %r" % self.__class__)
 
@@ -204,6 +206,8 @@ class _TypeAlias:
     False.
     """
 
+    __slots__ = ('name', 'type_var', 'impl_type', 'type_checker')
+
     def __new__(cls, *args, **kwds):
         """Constructor.
 
@@ -341,6 +345,8 @@ class Any(Final, metaclass=AnyMeta, _root=True):
     - As a special case, Any and object are subclasses of each other.
     """
 
+    __slots__ = ()
+
 
 class TypeVar(TypingMeta, metaclass=TypingMeta, _root=True):
     """Type variable.
@@ -635,6 +641,8 @@ class Optional(Final, metaclass=OptionalMeta, _root=True):
     Optional[X] is equivalent to Union[X, type(None)].
     """
 
+    __slots__ = ()
+
 
 class TupleMeta(TypingMeta):
     """Metaclass for Tuple."""
@@ -734,6 +742,8 @@ class Tuple(Final, metaclass=TupleMeta, _root=True):
     To specify a variable-length tuple of homogeneous type, use Sequence[T].
     """
 
+    __slots__ = ()
+
 
 class CallableMeta(TypingMeta):
     """Metaclass for Callable."""
@@ -840,6 +850,8 @@ class Callable(Final, metaclass=CallableMeta, _root=True):
     such function types are rarely used as callback types.
     """
 
+    __slots__ = ()
+
 
 def _gorg(a):
     """Return the farthest origin of a generic class."""
@@ -1042,6 +1054,8 @@ def lookup_name(mapping: Mapping[X, Y], key: X, default: Y) -> Y:
           # Same body as above.
     """
 
+    __slots__ = ()
+
     def __new__(cls, *args, **kwds):
         next_in_mro = object
         # Look for the last occurrence of Generic or Generic[...].
@@ -1208,6 +1222,7 @@ def _get_protocol_attrs(self):
                         attr != '__abstractmethods__' and
                         attr != '_is_protocol' and
                         attr != '__dict__' and
+                        attr != '__slots__' and
                         attr != '_get_protocol_attrs' and
                         attr != '__parameters__' and
                         attr != '__origin__' and
@@ -1225,6 +1240,8 @@ class _Protocol(metaclass=_ProtocolMeta):
     such as Hashable).
     """
 
+    __slots__ = ()
+
     _is_protocol = True
 
 
@@ -1235,56 +1252,63 @@ class _Protocol(metaclass=_ProtocolMeta):
 
 
 class Iterable(Generic[T_co], extra=collections_abc.Iterable):
-    pass
+    __slots__ = ()
 
 
 class Iterator(Iterable[T_co], extra=collections_abc.Iterator):
-    pass
+    __slots__ = ()
 
 
 class SupportsInt(_Protocol):
+    __slots__ = ()
 
     @abstractmethod
     def __int__(self) -> int:
         pass
 
 
 class SupportsFloat(_Protocol):
+    __slots__ = ()
 
     @abstractmethod
     def __float__(self) -> float:
         pass
 
 
 class SupportsComplex(_Protocol):
+    __slots__ = ()
 
     @abstractmethod
     def __complex__(self) -> complex:
         pass
 
 
 class SupportsBytes(_Protocol):
+    __slots__ = ()
 
     @abstractmethod
     def __bytes__(self) -> bytes:
         pass
 
 
 class SupportsAbs(_Protocol[T]):
+    __slots__ = ()
 
     @abstractmethod
     def __abs__(self) -> T:
         pass
 
 
 class SupportsRound(_Protocol[T]):
+    __slots__ = ()
 
     @abstractmethod
     def __round__(self, ndigits: int = 0) -> T:
         pass
 
 
 class Reversible(_Protocol[T]):
+    __slots__ = ()
 
     @abstractmethod
     def __reversed__(self) -> 'Iterator[T]':
@@ -1295,7 +1319,7 @@ def __reversed__(self) -> 'Iterator[T]':
 
 
 class Container(Generic[T_co], extra=collections_abc.Container):
-    pass
+    __slots__ = ()
 
 
 # Callable was defined earlier.
@@ -1369,6 +1393,7 @@ def __subclasscheck__(self, cls):
 
 
 class FrozenSet(frozenset, AbstractSet[T_co], metaclass=_FrozenSetMeta):
+    __slots__ = ()
 
     def __new__(cls, *args, **kwds):
         if _geqv(cls, FrozenSet):
@@ -1416,6 +1441,7 @@ def __new__(cls, *args, **kwds):
 
 class Generator(Iterator[T_co], Generic[T_co, T_contra, V_co],
                 extra=_G_base):
+    __slots__ = ()
 
     def __new__(cls, *args, **kwds):
         if _geqv(cls, Generator):
@@ -1459,6 +1485,8 @@ class IO(Generic[AnyStr]):
     way to track the other distinctions in the type system.
     """
 
+    __slots__ = ()
+
     @abstractproperty
     def mode(self) -> str:
         pass
@@ -1543,6 +1571,8 @@ def __exit__(self, type, value, traceback) -> None:
 class BinaryIO(IO[bytes]):
     """Typed version of the return of open() in binary mode."""
 
+    __slots__ = ()
+
     @abstractmethod
     def write(self, s: Union[bytes, bytearray]) -> int:
         pass
@@ -1555,6 +1585,8 @@ def __enter__(self) -> 'BinaryIO':
 class TextIO(IO[str]):
     """Typed version of the return of open() in text mode."""
 
+    __slots__ = ()
+
     @abstractproperty
     def buffer(self) -> BinaryIO:
         pass