Exclude the same special attributes from Protocol as CPython

mypy/nodes.py

@@ -3017,6 +3017,24 @@ class is generic then it will be a type constructor of higher kind.
         "is_intersection",
     ]
 
+    # Special attributes not collected as protocol members by Python 3.12
+    # See typing._SPECIAL_NAMES
+    EXCLUDED_ATTRIBUTES: Final = frozenset(
+        {
+            "__abstractmethods__",
+            "__annotations__",
+            "__dict__",
+            "__doc__",
+            "__init__",
+            "__module__",
+            "__new__",
+            "__slots__",
+            "__subclasshook__",
+            "__weakref__",
+            "__class_getitem__",  # Since Python 3.9
+        }
+    )
+
     def __init__(self, names: SymbolTable, defn: ClassDef, module_name: str) -> None:
         """Initialize a TypeInfo."""
         super().__init__()
@@ -3115,6 +3133,8 @@ def protocol_members(self) -> list[str]:
                     if isinstance(node.node, (TypeAlias, TypeVarExpr, MypyFile)):
                         # These are auxiliary definitions (and type aliases are prohibited).
                         continue
+                    if name in self.EXCLUDED_ATTRIBUTES:
+                        continue
                     members.add(name)
         return sorted(list(members))
 

test-data/unit/check-protocols.test

@@ -2789,6 +2789,65 @@ class A(Protocol):
 
 [builtins fixtures/tuple.pyi]
 
+[case testProtocolSlotsIsNotProtocolMember]
+# https://github.com/python/mypy/issues/11884
+from typing import Protocol
+
+class Foo(Protocol):
+    __slots__ = ()
+class NoSlots:
+    pass
+class EmptySlots:
+    __slots__ = ()
+class TupleSlots:
+    __slots__ = ('x', 'y')
+class StringSlots:
+    __slots__ = 'x y'
+def foo(f: Foo):
+    pass
+
+# All should pass:
+foo(NoSlots())
+foo(EmptySlots())
+foo(TupleSlots())
+foo(StringSlots())
+[builtins fixtures/tuple.pyi]
+
+[case testProtocolSlotsAndRuntimeCheckable]
+from typing import Protocol, runtime_checkable
+
+@runtime_checkable
+class Foo(Protocol):
+    __slots__ = ()
+class Bar:
+    pass
+issubclass(Bar, Foo)  # Used to be an error, when `__slots__` counted as a protocol member
+[builtins fixtures/isinstance.pyi]
+[typing fixtures/typing-full.pyi]
+
+
+[case testProtocolWithClassGetItem]
+# https://github.com/python/mypy/issues/11886
+from typing import Any, Iterable, Protocol, Union
+
+class B:
+    ...
+
+class C:
+    def __class_getitem__(cls, __item: Any) -> Any:
+        ...
+
+class SupportsClassGetItem(Protocol):
+    __slots__: Union[str, Iterable[str]] = ()
+    def __class_getitem__(cls, __item: Any) -> Any:
+        ...
+
+b1: SupportsClassGetItem = B()
+c1: SupportsClassGetItem = C()
+[builtins fixtures/tuple.pyi]
+[typing fixtures/typing-full.pyi]
+
+
 [case testNoneVsProtocol]
 # mypy: strict-optional
 from typing_extensions import Protocol