cpython/Lib/test/test_typing.py

import contextlib
import collections
import collections.abc
from collections import defaultdict
from functools import lru_cache, wraps, reduce
import gc
import inspect
import itertools
import operator
import pickle
import re
import sys
from unittest import TestCase, main, skip
from unittest.mock import patch
from copy import copy, deepcopy

from typing import Any, NoReturn, Never, assert_never
from typing import overload, get_overloads, clear_overloads
from typing import TypeVar, TypeVarTuple, Unpack, AnyStr
from typing import T, KT, VT  # Not in __all__.
from typing import Union, Optional, Literal
from typing import Tuple, List, Dict, MutableMapping
from typing import Callable
from typing import Generic, ClassVar, Final, final, Protocol
from typing import assert_type, cast, runtime_checkable
from typing import get_type_hints
from typing import get_origin, get_args, get_protocol_members
from typing import override
from typing import is_typeddict, is_protocol
from typing import reveal_type
from typing import dataclass_transform
from typing import no_type_check, no_type_check_decorator
from typing import Type
from typing import NamedTuple, NotRequired, Required, ReadOnly, TypedDict
from typing import IO, TextIO, BinaryIO
from typing import Pattern, Match
from typing import Annotated, ForwardRef
from typing import Self, LiteralString
from typing import TypeAlias
from typing import ParamSpec, Concatenate, ParamSpecArgs, ParamSpecKwargs
from typing import TypeGuard, TypeIs, NoDefault
import abc
import textwrap
import typing
import weakref
import types

from test.support import captured_stderr, cpython_only, infinite_recursion, requires_docstrings, import_helper
from test.typinganndata import ann_module695, mod_generics_cache, _typed_dict_helper


CANNOT_SUBCLASS_TYPE = 'Cannot subclass special typing classes'
NOT_A_BASE_TYPE = "type 'typing.%s' is not an acceptable base type"
CANNOT_SUBCLASS_INSTANCE = 'Cannot subclass an instance of %s'


class BaseTestCase(TestCase):

    def assertIsSubclass(self, cls, class_or_tuple, msg=None):
        if not issubclass(cls, class_or_tuple):
            message = '%r is not a subclass of %r' % (cls, class_or_tuple)
            if msg is not None:
                message += ' : %s' % msg
            raise self.failureException(message)

    def assertNotIsSubclass(self, cls, class_or_tuple, msg=None):
        if issubclass(cls, class_or_tuple):
            message = '%r is a subclass of %r' % (cls, class_or_tuple)
            if msg is not None:
                message += ' : %s' % msg
            raise self.failureException(message)

    def clear_caches(self):
        for f in typing._cleanups:
            f()


def all_pickle_protocols(test_func):
    """Runs `test_func` with various values for `proto` argument."""

    @wraps(test_func)
    def wrapper(self):
        for proto in range(pickle.HIGHEST_PROTOCOL + 1):
            with self.subTest(pickle_proto=proto):
                test_func(self, proto=proto)

    return wrapper


class Employee:
    pass


class Manager(Employee):
    pass


class Founder(Employee):
    pass


class ManagingFounder(Manager, Founder):
    pass


class AnyTests(BaseTestCase):

    def test_any_instance_type_error(self):
        with self.assertRaises(TypeError):
            isinstance(42, Any)

    def test_repr(self):
        self.assertEqual(repr(Any), 'typing.Any')

        class Sub(Any): pass
        self.assertEqual(
            repr(Sub),
            f"<class '{__name__}.AnyTests.test_repr.<locals>.Sub'>",
        )

    def test_errors(self):
        with self.assertRaises(TypeError):
            issubclass(42, Any)
        with self.assertRaises(TypeError):
            Any[int]  # Any is not a generic type.

    def test_can_subclass(self):
        class Mock(Any): pass
        self.assertTrue(issubclass(Mock, Any))
        self.assertIsInstance(Mock(), Mock)

        class Something: pass
        self.assertFalse(issubclass(Something, Any))
        self.assertNotIsInstance(Something(), Mock)

        class MockSomething(Something, Mock): pass
        self.assertTrue(issubclass(MockSomething, Any))
        ms = MockSomething()
        self.assertIsInstance(ms, MockSomething)
        self.assertIsInstance(ms, Something)
        self.assertIsInstance(ms, Mock)

    def test_subclassing_with_custom_constructor(self):
        class Sub(Any):
            def __init__(self, *args, **kwargs): pass
        # The instantiation must not fail.
        Sub(0, s="")

    def test_multiple_inheritance_with_custom_constructors(self):
        class Foo:
            def __init__(self, x):
                self.x = x

        class Bar(Any, Foo):
            def __init__(self, x, y):
                self.y = y
                super().__init__(x)

        b = Bar(1, 2)
        self.assertEqual(b.x, 1)
        self.assertEqual(b.y, 2)

    def test_cannot_instantiate(self):
        with self.assertRaises(TypeError):
            Any()
        with self.assertRaises(TypeError):
            type(Any)()

    def test_any_works_with_alias(self):
        # These expressions must simply not fail.
        typing.Match[Any]
        typing.Pattern[Any]
        typing.IO[Any]


class BottomTypeTestsMixin:
    bottom_type: ClassVar[Any]

    def test_equality(self):
        self.assertEqual(self.bottom_type, self.bottom_type)
        self.assertIs(self.bottom_type, self.bottom_type)
        self.assertNotEqual(self.bottom_type, None)

    def test_get_origin(self):
        self.assertIs(get_origin(self.bottom_type), None)

    def test_instance_type_error(self):
        with self.assertRaises(TypeError):
            isinstance(42, self.bottom_type)

    def test_subclass_type_error(self):
        with self.assertRaises(TypeError):
            issubclass(Employee, self.bottom_type)
        with self.assertRaises(TypeError):
            issubclass(NoReturn, self.bottom_type)

    def test_not_generic(self):
        with self.assertRaises(TypeError):
            self.bottom_type[int]

    def test_cannot_subclass(self):
        with self.assertRaisesRegex(TypeError,
                'Cannot subclass ' + re.escape(str(self.bottom_type))):
            class A(self.bottom_type):
                pass
        with self.assertRaisesRegex(TypeError, CANNOT_SUBCLASS_TYPE):
            class B(type(self.bottom_type)):
                pass

    def test_cannot_instantiate(self):
        with self.assertRaises(TypeError):
            self.bottom_type()
        with self.assertRaises(TypeError):
            type(self.bottom_type)()


class NoReturnTests(BottomTypeTestsMixin, BaseTestCase):
    bottom_type = NoReturn

    def test_repr(self):
        self.assertEqual(repr(NoReturn), 'typing.NoReturn')

    def test_get_type_hints(self):
        def some(arg: NoReturn) -> NoReturn: ...
        def some_str(arg: 'NoReturn') -> 'typing.NoReturn': ...

        expected = {'arg': NoReturn, 'return': NoReturn}
        for target in [some, some_str]:
            with self.subTest(target=target):
                self.assertEqual(gth(target), expected)

    def test_not_equality(self):
        self.assertNotEqual(NoReturn, Never)
        self.assertNotEqual(Never, NoReturn)


class NeverTests(BottomTypeTestsMixin, BaseTestCase):
    bottom_type = Never

    def test_repr(self):
        self.assertEqual(repr(Never), 'typing.Never')

    def test_get_type_hints(self):
        def some(arg: Never) -> Never: ...
        def some_str(arg: 'Never') -> 'typing.Never': ...

        expected = {'arg': Never, 'return': Never}
        for target in [some, some_str]:
            with self.subTest(target=target):
                self.assertEqual(gth(target), expected)


class AssertNeverTests(BaseTestCase):
    def test_exception(self):
        with self.assertRaises(AssertionError):
            assert_never(None)

        value = "some value"
        with self.assertRaisesRegex(AssertionError, value):
            assert_never(value)

        # Make sure a huge value doesn't get printed in its entirety
        huge_value = "a" * 10000
        with self.assertRaises(AssertionError) as cm:
            assert_never(huge_value)
        self.assertLess(
            len(cm.exception.args[0]),
            typing._ASSERT_NEVER_REPR_MAX_LENGTH * 2,
        )


class SelfTests(BaseTestCase):
    def test_equality(self):
        self.assertEqual(Self, Self)
        self.assertIs(Self, Self)
        self.assertNotEqual(Self, None)

    def test_basics(self):
        class Foo:
            def bar(self) -> Self: ...
        class FooStr:
            def bar(self) -> 'Self': ...
        class FooStrTyping:
            def bar(self) -> 'typing.Self': ...

        for target in [Foo, FooStr, FooStrTyping]:
            with self.subTest(target=target):
                self.assertEqual(gth(target.bar), {'return': Self})
        self.assertIs(get_origin(Self), None)

    def test_repr(self):
        self.assertEqual(repr(Self), 'typing.Self')

    def test_cannot_subscript(self):
        with self.assertRaises(TypeError):
            Self[int]

    def test_cannot_subclass(self):
        with self.assertRaisesRegex(TypeError, CANNOT_SUBCLASS_TYPE):
            class C(type(Self)):
                pass
        with self.assertRaisesRegex(TypeError,
                r'Cannot subclass typing\.Self'):
            class D(Self):
                pass

    def test_cannot_init(self):
        with self.assertRaises(TypeError):
            Self()
        with self.assertRaises(TypeError):
            type(Self)()

    def test_no_isinstance(self):
        with self.assertRaises(TypeError):
            isinstance(1, Self)
        with self.assertRaises(TypeError):
            issubclass(int, Self)

    def test_alias(self):
        # TypeAliases are not actually part of the spec
        alias_1 = Tuple[Self, Self]
        alias_2 = List[Self]
        alias_3 = ClassVar[Self]
        self.assertEqual(get_args(alias_1), (Self, Self))
        self.assertEqual(get_args(alias_2), (Self,))
        self.assertEqual(get_args(alias_3), (Self,))


class LiteralStringTests(BaseTestCase):
    def test_equality(self):
        self.assertEqual(LiteralString, LiteralString)
        self.assertIs(LiteralString, LiteralString)
        self.assertNotEqual(LiteralString, None)

    def test_basics(self):
        class Foo:
            def bar(self) -> LiteralString: ...
        class FooStr:
            def bar(self) -> 'LiteralString': ...
        class FooStrTyping:
            def bar(self) -> 'typing.LiteralString': ...

        for target in [Foo, FooStr, FooStrTyping]:
            with self.subTest(target=target):
                self.assertEqual(gth(target.bar), {'return': LiteralString})
        self.assertIs(get_origin(LiteralString), None)

    def test_repr(self):
        self.assertEqual(repr(LiteralString), 'typing.LiteralString')

    def test_cannot_subscript(self):
        with self.assertRaises(TypeError):
            LiteralString[int]

    def test_cannot_subclass(self):
        with self.assertRaisesRegex(TypeError, CANNOT_SUBCLASS_TYPE):
            class C(type(LiteralString)):
                pass
        with self.assertRaisesRegex(TypeError,
                r'Cannot subclass typing\.LiteralString'):
            class D(LiteralString):
                pass

    def test_cannot_init(self):
        with self.assertRaises(TypeError):
            LiteralString()
        with self.assertRaises(TypeError):
            type(LiteralString)()

    def test_no_isinstance(self):
        with self.assertRaises(TypeError):
            isinstance(1, LiteralString)
        with self.assertRaises(TypeError):
            issubclass(int, LiteralString)

    def test_alias(self):
        alias_1 = Tuple[LiteralString, LiteralString]
        alias_2 = List[LiteralString]
        alias_3 = ClassVar[LiteralString]
        self.assertEqual(get_args(alias_1), (LiteralString, LiteralString))
        self.assertEqual(get_args(alias_2), (LiteralString,))
        self.assertEqual(get_args(alias_3), (LiteralString,))

class TypeVarTests(BaseTestCase):
    def test_basic_plain(self):
        T = TypeVar('T')
        # T equals itself.
        self.assertEqual(T, T)
        # T is an instance of TypeVar
        self.assertIsInstance(T, TypeVar)
        self.assertEqual(T.__name__, 'T')
        self.assertEqual(T.__constraints__, ())
        self.assertIs(T.__bound__, None)
        self.assertIs(T.__covariant__, False)
        self.assertIs(T.__contravariant__, False)
        self.assertIs(T.__infer_variance__, False)
        self.assertEqual(T.__module__, __name__)

    def test_basic_with_exec(self):
        ns = {}
        exec('from typing import TypeVar; T = TypeVar("T", bound=float)', ns, ns)
        T = ns['T']
        self.assertIsInstance(T, TypeVar)
        self.assertEqual(T.__name__, 'T')
        self.assertEqual(T.__constraints__, ())
        self.assertIs(T.__bound__, float)
        self.assertIs(T.__covariant__, False)
        self.assertIs(T.__contravariant__, False)
        self.assertIs(T.__infer_variance__, False)
        self.assertIs(T.__module__, None)

    def test_attributes(self):
        T_bound = TypeVar('T_bound', bound=int)
        self.assertEqual(T_bound.__name__, 'T_bound')
        self.assertEqual(T_bound.__constraints__, ())
        self.assertIs(T_bound.__bound__, int)

        T_constraints = TypeVar('T_constraints', int, str)
        self.assertEqual(T_constraints.__name__, 'T_constraints')
        self.assertEqual(T_constraints.__constraints__, (int, str))
        self.assertIs(T_constraints.__bound__, None)

        T_co = TypeVar('T_co', covariant=True)
        self.assertEqual(T_co.__name__, 'T_co')
        self.assertIs(T_co.__covariant__, True)
        self.assertIs(T_co.__contravariant__, False)
        self.assertIs(T_co.__infer_variance__, False)

        T_contra = TypeVar('T_contra', contravariant=True)
        self.assertEqual(T_contra.__name__, 'T_contra')
        self.assertIs(T_contra.__covariant__, False)
        self.assertIs(T_contra.__contravariant__, True)
        self.assertIs(T_contra.__infer_variance__, False)

        T_infer = TypeVar('T_infer', infer_variance=True)
        self.assertEqual(T_infer.__name__, 'T_infer')
        self.assertIs(T_infer.__covariant__, False)
        self.assertIs(T_infer.__contravariant__, False)
        self.assertIs(T_infer.__infer_variance__, True)

    def test_typevar_instance_type_error(self):
        T = TypeVar('T')
        with self.assertRaises(TypeError):
            isinstance(42, T)

    def test_typevar_subclass_type_error(self):
        T = TypeVar('T')
        with self.assertRaises(TypeError):
            issubclass(int, T)
        with self.assertRaises(TypeError):
            issubclass(T, int)

    def test_constrained_error(self):
        with self.assertRaises(TypeError):
            X = TypeVar('X', int)
            X

    def test_union_unique(self):
        X = TypeVar('X')
        Y = TypeVar('Y')
        self.assertNotEqual(X, Y)
        self.assertEqual(Union[X], X)
        self.assertNotEqual(Union[X], Union[X, Y])
        self.assertEqual(Union[X, X], X)
        self.assertNotEqual(Union[X, int], Union[X])
        self.assertNotEqual(Union[X, int], Union[int])
        self.assertEqual(Union[X, int].__args__, (X, int))
        self.assertEqual(Union[X, int].__parameters__, (X,))
        self.assertIs(Union[X, int].__origin__, Union)

    def test_or(self):
        X = TypeVar('X')
        # use a string because str doesn't implement
        # __or__/__ror__ itself
        self.assertEqual(X | "x", Union[X, "x"])
        self.assertEqual("x" | X, Union["x", X])
        # make sure the order is correct
        self.assertEqual(get_args(X | "x"), (X, ForwardRef("x")))
        self.assertEqual(get_args("x" | X), (ForwardRef("x"), X))

    def test_union_constrained(self):
        A = TypeVar('A', str, bytes)
        self.assertNotEqual(Union[A, str], Union[A])

    def test_repr(self):
        self.assertEqual(repr(T), '~T')
        self.assertEqual(repr(KT), '~KT')
        self.assertEqual(repr(VT), '~VT')
        self.assertEqual(repr(AnyStr), '~AnyStr')
        T_co = TypeVar('T_co', covariant=True)
        self.assertEqual(repr(T_co), '+T_co')
        T_contra = TypeVar('T_contra', contravariant=True)
        self.assertEqual(repr(T_contra), '-T_contra')

    def test_no_redefinition(self):
        self.assertNotEqual(TypeVar('T'), TypeVar('T'))
        self.assertNotEqual(TypeVar('T', int, str), TypeVar('T', int, str))

    def test_cannot_subclass(self):
        with self.assertRaisesRegex(TypeError, NOT_A_BASE_TYPE % 'TypeVar'):
            class V(TypeVar): pass
        T = TypeVar("T")
        with self.assertRaisesRegex(TypeError,
                CANNOT_SUBCLASS_INSTANCE % 'TypeVar'):
            class W(T): pass

    def test_cannot_instantiate_vars(self):
        with self.assertRaises(TypeError):
            TypeVar('A')()

    def test_bound_errors(self):
        with self.assertRaises(TypeError):
            TypeVar('X', bound=Union)
        with self.assertRaises(TypeError):
            TypeVar('X', str, float, bound=Employee)
        with self.assertRaisesRegex(TypeError,
                                    r"Bound must be a type\. Got \(1, 2\)\."):
            TypeVar('X', bound=(1, 2))

    def test_missing__name__(self):
        # See bpo-39942
        code = ("import typing\n"
                "T = typing.TypeVar('T')\n"
                )
        exec(code, {})

    def test_no_bivariant(self):
        with self.assertRaises(ValueError):
            TypeVar('T', covariant=True, contravariant=True)

    def test_cannot_combine_explicit_and_infer(self):
        with self.assertRaises(ValueError):
            TypeVar('T', covariant=True, infer_variance=True)
        with self.assertRaises(ValueError):
            TypeVar('T', contravariant=True, infer_variance=True)

    def test_var_substitution(self):
        T = TypeVar('T')
        subst = T.__typing_subst__
        self.assertIs(subst(int), int)
        self.assertEqual(subst(list[int]), list[int])
        self.assertEqual(subst(List[int]), List[int])
        self.assertEqual(subst(List), List)
        self.assertIs(subst(Any), Any)
        self.assertIs(subst(None), type(None))
        self.assertIs(subst(T), T)
        self.assertEqual(subst(int|str), int|str)
        self.assertEqual(subst(Union[int, str]), Union[int, str])

    def test_bad_var_substitution(self):
        T = TypeVar('T')
        bad_args = (
            (), (int, str), Union,
            Generic, Generic[T], Protocol, Protocol[T],
            Final, Final[int], ClassVar, ClassVar[int],
        )
        for arg in bad_args:
            with self.subTest(arg=arg):
                with self.assertRaises(TypeError):
                    T.__typing_subst__(arg)
                with self.assertRaises(TypeError):
                    List[T][arg]
                with self.assertRaises(TypeError):
                    list[T][arg]

    def test_many_weakrefs(self):
        # gh-108295: this used to segfault
        for cls in (ParamSpec, TypeVarTuple, TypeVar):
            with self.subTest(cls=cls):
                vals = weakref.WeakValueDictionary()

                for x in range(10):
                    vals[x] = cls(str(x))
                del vals

    def test_constructor(self):
        T = TypeVar(name="T")
        self.assertEqual(T.__name__, "T")
        self.assertEqual(T.__constraints__, ())
        self.assertIs(T.__bound__, None)


class TypeParameterDefaultsTests(BaseTestCase):
    def test_typevar(self):
        T = TypeVar('T', default=int)
        self.assertEqual(T.__default__, int)
        self.assertTrue(T.has_default())
        self.assertIsInstance(T, TypeVar)

        class A(Generic[T]): ...
        Alias = Optional[T]

    def test_typevar_none(self):
        U = TypeVar('U')
        U_None = TypeVar('U_None', default=None)
        self.assertIs(U.__default__, NoDefault)
        self.assertFalse(U.has_default())
        self.assertIs(U_None.__default__, None)
        self.assertTrue(U_None.has_default())

        class X[T]: ...
        T, = X.__type_params__
        self.assertIs(T.__default__, NoDefault)
        self.assertFalse(T.has_default())

    def test_paramspec(self):
        P = ParamSpec('P', default=(str, int))
        self.assertEqual(P.__default__, (str, int))
        self.assertTrue(P.has_default())
        self.assertIsInstance(P, ParamSpec)

        class A(Generic[P]): ...
        Alias = typing.Callable[P, None]

        P_default = ParamSpec('P_default', default=...)
        self.assertIs(P_default.__default__, ...)

    def test_paramspec_none(self):
        U = ParamSpec('U')
        U_None = ParamSpec('U_None', default=None)
        self.assertIs(U.__default__, NoDefault)
        self.assertFalse(U.has_default())
        self.assertIs(U_None.__default__, None)
        self.assertTrue(U_None.has_default())

        class X[**P]: ...
        P, = X.__type_params__
        self.assertIs(P.__default__, NoDefault)
        self.assertFalse(P.has_default())

    def test_typevartuple(self):
        Ts = TypeVarTuple('Ts', default=Unpack[Tuple[str, int]])
        self.assertEqual(Ts.__default__, Unpack[Tuple[str, int]])
        self.assertTrue(Ts.has_default())
        self.assertIsInstance(Ts, TypeVarTuple)

        class A(Generic[Unpack[Ts]]): ...
        Alias = Optional[Unpack[Ts]]

    def test_typevartuple_specialization(self):
        T = TypeVar("T")
        Ts = TypeVarTuple('Ts', default=Unpack[Tuple[str, int]])
        self.assertEqual(Ts.__default__, Unpack[Tuple[str, int]])
        class A(Generic[T, Unpack[Ts]]): ...
        self.assertEqual(A[float].__args__, (float, str, int))
        self.assertEqual(A[float, range].__args__, (float, range))
        self.assertEqual(A[float, *tuple[int, ...]].__args__, (float, *tuple[int, ...]))

    def test_typevar_and_typevartuple_specialization(self):
        T = TypeVar("T")
        U = TypeVar("U", default=float)
        Ts = TypeVarTuple('Ts', default=Unpack[Tuple[str, int]])
        self.assertEqual(Ts.__default__, Unpack[Tuple[str, int]])
        class A(Generic[T, U, Unpack[Ts]]): ...
        self.assertEqual(A[int].__args__, (int, float, str, int))
        self.assertEqual(A[int, str].__args__, (int, str, str, int))
        self.assertEqual(A[int, str, range].__args__, (int, str, range))
        self.assertEqual(A[int, str, *tuple[int, ...]].__args__, (int, str, *tuple[int, ...]))

    def test_no_default_after_typevar_tuple(self):
        T = TypeVar("T", default=int)
        Ts = TypeVarTuple("Ts")
        Ts_default = TypeVarTuple("Ts_default", default=Unpack[Tuple[str, int]])

        with self.assertRaises(TypeError):
            class X(Generic[*Ts, T]): ...

        with self.assertRaises(TypeError):
            class Y(Generic[*Ts_default, T]): ...

    def test_allow_default_after_non_default_in_alias(self):
        T_default = TypeVar('T_default', default=int)
        T = TypeVar('T')
        Ts = TypeVarTuple('Ts')

        a1 = Callable[[T_default], T]
        self.assertEqual(a1.__args__, (T_default, T))

        a2 = dict[T_default, T]
        self.assertEqual(a2.__args__, (T_default, T))

        a3 = typing.Dict[T_default, T]
        self.assertEqual(a3.__args__, (T_default, T))

        a4 = Callable[*Ts, T]
        self.assertEqual(a4.__args__, (*Ts, T))

    def test_paramspec_specialization(self):
        T = TypeVar("T")
        P = ParamSpec('P', default=[str, int])
        self.assertEqual(P.__default__, [str, int])
        class A(Generic[T, P]): ...
        self.assertEqual(A[float].__args__, (float, (str, int)))
        self.assertEqual(A[float, [range]].__args__, (float, (range,)))

    def test_typevar_and_paramspec_specialization(self):
        T = TypeVar("T")
        U = TypeVar("U", default=float)
        P = ParamSpec('P', default=[str, int])
        self.assertEqual(P.__default__, [str, int])
        class A(Generic[T, U, P]): ...
        self.assertEqual(A[float].__args__, (float, float, (str, int)))
        self.assertEqual(A[float, int].__args__, (float, int, (str, int)))
        self.assertEqual(A[float, int, [range]].__args__, (float, int, (range,)))

    def test_paramspec_and_typevar_specialization(self):
        T = TypeVar("T")
        P = ParamSpec('P', default=[str, int])
        U = TypeVar("U", default=float)
        self.assertEqual(P.__default__, [str, int])
        class A(Generic[T, P, U]): ...
        self.assertEqual(A[float].__args__, (float, (str, int), float))
        self.assertEqual(A[float, [range]].__args__, (float, (range,), float))
        self.assertEqual(A[float, [range], int].__args__, (float, (range,), int))

    def test_typevartuple_none(self):
        U = TypeVarTuple('U')
        U_None = TypeVarTuple('U_None', default=None)
        self.assertIs(U.__default__, NoDefault)
        self.assertFalse(U.has_default())
        self.assertIs(U_None.__default__, None)
        self.assertTrue(U_None.has_default())

        class X[**Ts]: ...
        Ts, = X.__type_params__
        self.assertIs(Ts.__default__, NoDefault)
        self.assertFalse(Ts.has_default())

    def test_no_default_after_non_default(self):
        DefaultStrT = TypeVar('DefaultStrT', default=str)
        T = TypeVar('T')

        with self.assertRaisesRegex(
            TypeError, r"Type parameter ~T without a default follows type parameter with a default"
        ):
            Test = Generic[DefaultStrT, T]

    def test_need_more_params(self):
        DefaultStrT = TypeVar('DefaultStrT', default=str)
        T = TypeVar('T')
        U = TypeVar('U')

        class A(Generic[T, U, DefaultStrT]): ...
        A[int, bool]
        A[int, bool, str]

        with self.assertRaisesRegex(
            TypeError, r"Too few arguments for .+; actual 1, expected at least 2"
        ):
            Test = A[int]

    def test_pickle(self):
        global U, U_co, U_contra, U_default  # pickle wants to reference the class by name
        U = TypeVar('U')
        U_co = TypeVar('U_co', covariant=True)
        U_contra = TypeVar('U_contra', contravariant=True)
        U_default = TypeVar('U_default', default=int)
        for proto in range(pickle.HIGHEST_PROTOCOL):
            for typevar in (U, U_co, U_contra, U_default):
                z = pickle.loads(pickle.dumps(typevar, proto))
                self.assertEqual(z.__name__, typevar.__name__)
                self.assertEqual(z.__covariant__, typevar.__covariant__)
                self.assertEqual(z.__contravariant__, typevar.__contravariant__)
                self.assertEqual(z.__bound__, typevar.__bound__)
                self.assertEqual(z.__default__, typevar.__default__)


def template_replace(templates: list[str], replacements: dict[str, list[str]]) -> list[tuple[str]]:
    """Renders templates with possible combinations of replacements.

    Example 1: Suppose that:
      templates = ["dog_breed are awesome", "dog_breed are cool"]
      replacements = ["dog_breed": ["Huskies", "Beagles"]]
    Then we would return:
      [
          ("Huskies are awesome", "Huskies are cool"),
          ("Beagles are awesome", "Beagles are cool")
      ]

    Example 2: Suppose that:
      templates = ["Huskies are word1 but also word2"]
      replacements = {"word1": ["playful", "cute"],
                      "word2": ["feisty", "tiring"]}
    Then we would return:
      [
          ("Huskies are playful but also feisty"),
          ("Huskies are playful but also tiring"),
          ("Huskies are cute but also feisty"),
          ("Huskies are cute but also tiring")
      ]

    Note that if any of the replacements do not occur in any template:
      templates = ["Huskies are word1", "Beagles!"]
      replacements = {"word1": ["playful", "cute"],
                      "word2": ["feisty", "tiring"]}
    Then we do not generate duplicates, returning:
      [
          ("Huskies are playful", "Beagles!"),
          ("Huskies are cute", "Beagles!")
      ]
    """
    # First, build a structure like:
    #   [
    #     [("word1", "playful"), ("word1", "cute")],
    #     [("word2", "feisty"), ("word2", "tiring")]
    #   ]
    replacement_combos = []
    for original, possible_replacements in replacements.items():
        original_replacement_tuples = []
        for replacement in possible_replacements:
            original_replacement_tuples.append((original, replacement))
        replacement_combos.append(original_replacement_tuples)

    # Second, generate rendered templates, including possible duplicates.
    rendered_templates = []
    for replacement_combo in itertools.product(*replacement_combos):
        # replacement_combo would be e.g.
        #   [("word1", "playful"), ("word2", "feisty")]
        templates_with_replacements = []
        for template in templates:
            for original, replacement in replacement_combo:
                template = template.replace(original, replacement)
            templates_with_replacements.append(template)
        rendered_templates.append(tuple(templates_with_replacements))

    # Finally, remove the duplicates (but keep the order).
    rendered_templates_no_duplicates = []
    for x in rendered_templates:
        # Inefficient, but should be fine for our purposes.
        if x not in rendered_templates_no_duplicates:
            rendered_templates_no_duplicates.append(x)

    return rendered_templates_no_duplicates


class TemplateReplacementTests(BaseTestCase):

    def test_two_templates_two_replacements_yields_correct_renders(self):
        actual = template_replace(
                templates=["Cats are word1", "Dogs are word2"],
                replacements={
                    "word1": ["small", "cute"],
                    "word2": ["big", "fluffy"],
                },
        )
        expected = [
            ("Cats are small", "Dogs are big"),
            ("Cats are small", "Dogs are fluffy"),
            ("Cats are cute", "Dogs are big"),
            ("Cats are cute", "Dogs are fluffy"),
        ]
        self.assertEqual(actual, expected)

    def test_no_duplicates_if_replacement_not_in_templates(self):
        actual = template_replace(
                templates=["Cats are word1", "Dogs!"],
                replacements={
                    "word1": ["small", "cute"],
                    "word2": ["big", "fluffy"],
                },
        )
        expected = [
            ("Cats are small", "Dogs!"),
            ("Cats are cute", "Dogs!"),
        ]
        self.assertEqual(actual, expected)


class GenericAliasSubstitutionTests(BaseTestCase):
    """Tests for type variable substitution in generic aliases.

    For variadic cases, these tests should be regarded as the source of truth,
    since we hadn't realised the full complexity of variadic substitution
    at the time of finalizing PEP 646. For full discussion, see
    https://github.com/python/cpython/issues/91162.
    """

    def test_one_parameter(self):
        T = TypeVar('T')
        Ts = TypeVarTuple('Ts')
        Ts2 = TypeVarTuple('Ts2')

        class C(Generic[T]): pass

        generics = ['C', 'list', 'List']
        tuple_types = ['tuple', 'Tuple']

        tests = [
            # Alias                               # Args                     # Expected result
            ('generic[T]',                        '[()]',                    'TypeError'),
            ('generic[T]',                        '[int]',                   'generic[int]'),
            ('generic[T]',                        '[int, str]',              'TypeError'),
            ('generic[T]',                        '[tuple_type[int, ...]]',  'generic[tuple_type[int, ...]]'),
            ('generic[T]',                        '[*tuple_type[int]]',      'generic[int]'),
            ('generic[T]',                        '[*tuple_type[()]]',       'TypeError'),
            ('generic[T]',                        '[*tuple_type[int, str]]', 'TypeError'),
            ('generic[T]',                        '[*tuple_type[int, ...]]', 'TypeError'),
            ('generic[T]',                        '[*Ts]',                   'TypeError'),
            ('generic[T]',                        '[T, *Ts]',                'TypeError'),
            ('generic[T]',                        '[*Ts, T]',                'TypeError'),
            # Raises TypeError because C is not variadic.
            # (If C _were_ variadic, it'd be fine.)
            ('C[T, *tuple_type[int, ...]]',       '[int]',                   'TypeError'),
            # Should definitely raise TypeError: list only takes one argument.
            ('list[T, *tuple_type[int, ...]]',    '[int]',                   'list[int, *tuple_type[int, ...]]'),
            ('List[T, *tuple_type[int, ...]]',    '[int]',                   'TypeError'),
            # Should raise, because more than one `TypeVarTuple` is not supported.
            ('generic[*Ts, *Ts2]',                '[int]',                   'TypeError'),
        ]

        for alias_template, args_template, expected_template in tests:
            rendered_templates = template_replace(
                    templates=[alias_template, args_template, expected_template],
                    replacements={'generic': generics, 'tuple_type': tuple_types}
            )
            for alias_str, args_str, expected_str in rendered_templates:
                with self.subTest(alias=alias_str, args=args_str, expected=expected_str):
                    if expected_str == 'TypeError':
                        with self.assertRaises(TypeError):
                            eval(alias_str + args_str)
                    else:
                        self.assertEqual(
                            eval(alias_str + args_str),
                            eval(expected_str)
                        )


    def test_two_parameters(self):
        T1 = TypeVar('T1')
        T2 = TypeVar('T2')
        Ts = TypeVarTuple('Ts')

        class C(Generic[T1, T2]): pass

        generics = ['C', 'dict', 'Dict']
        tuple_types = ['tuple', 'Tuple']

        tests = [
            # Alias                                    # Args                                               # Expected result
            ('generic[T1, T2]',                        '[()]',                                              'TypeError'),
            ('generic[T1, T2]',                        '[int]',                                             'TypeError'),
            ('generic[T1, T2]',                        '[int, str]',                                        'generic[int, str]'),
            ('generic[T1, T2]',                        '[int, str, bool]',                                  'TypeError'),
            ('generic[T1, T2]',                        '[*tuple_type[int]]',                                'TypeError'),
            ('generic[T1, T2]',                        '[*tuple_type[int, str]]',                           'generic[int, str]'),
            ('generic[T1, T2]',                        '[*tuple_type[int, str, bool]]',                     'TypeError'),

            ('generic[T1, T2]',                        '[int, *tuple_type[str]]',                           'generic[int, str]'),
            ('generic[T1, T2]',                        '[*tuple_type[int], str]',                           'generic[int, str]'),
            ('generic[T1, T2]',                        '[*tuple_type[int], *tuple_type[str]]',              'generic[int, str]'),
            ('generic[T1, T2]',                        '[*tuple_type[int, str], *tuple_type[()]]',          'generic[int, str]'),
            ('generic[T1, T2]',                        '[*tuple_type[()], *tuple_type[int, str]]',          'generic[int, str]'),
            ('generic[T1, T2]',                        '[*tuple_type[int], *tuple_type[()]]',               'TypeError'),
            ('generic[T1, T2]',                        '[*tuple_type[()], *tuple_type[int]]',               'TypeError'),
            ('generic[T1, T2]',                        '[*tuple_type[int, str], *tuple_type[float]]',       'TypeError'),
            ('generic[T1, T2]',                        '[*tuple_type[int], *tuple_type[str, float]]',       'TypeError'),
            ('generic[T1, T2]',                        '[*tuple_type[int, str], *tuple_type[float, bool]]', 'TypeError'),

            ('generic[T1, T2]',                        '[tuple_type[int, ...]]',                            'TypeError'),
            ('generic[T1, T2]',                        '[tuple_type[int, ...], tuple_type[str, ...]]',      'generic[tuple_type[int, ...], tuple_type[str, ...]]'),
            ('generic[T1, T2]',                        '[*tuple_type[int, ...]]',                           'TypeError'),
            ('generic[T1, T2]',                        '[int, *tuple_type[str, ...]]',                      'TypeError'),
            ('generic[T1, T2]',                        '[*tuple_type[int, ...], str]',                      'TypeError'),
            ('generic[T1, T2]',                        '[*tuple_type[int, ...], *tuple_type[str, ...]]',    'TypeError'),
            ('generic[T1, T2]',                        '[*Ts]',                                             'TypeError'),
            ('generic[T1, T2]',                        '[T, *Ts]',                                          'TypeError'),
            ('generic[T1, T2]',                        '[*Ts, T]',                                          'TypeError'),
            # This one isn't technically valid - none of the things that
            # `generic` can be (defined in `generics` above) are variadic, so we
            # shouldn't really be able to do `generic[T1, *tuple_type[int, ...]]`.
            # So even if type checkers shouldn't allow it, we allow it at
            # runtime, in accordance with a general philosophy of "Keep the
            # runtime lenient so people can experiment with typing constructs".
            ('generic[T1, *tuple_type[int, ...]]',     '[str]',                                             'generic[str, *tuple_type[int, ...]]'),
        ]

        for alias_template, args_template, expected_template in tests:
            rendered_templates = template_replace(
                    templates=[alias_template, args_template, expected_template],
                    replacements={'generic': generics, 'tuple_type': tuple_types}
            )
            for alias_str, args_str, expected_str in rendered_templates:
                with self.subTest(alias=alias_str, args=args_str, expected=expected_str):
                    if expected_str == 'TypeError':
                        with self.assertRaises(TypeError):
                            eval(alias_str + args_str)
                    else:
                        self.assertEqual(
                            eval(alias_str + args_str),
                            eval(expected_str)
                        )

    def test_three_parameters(self):
        T1 = TypeVar('T1')
        T2 = TypeVar('T2')
        T3 = TypeVar('T3')

        class C(Generic[T1, T2, T3]): pass

        generics = ['C']
        tuple_types = ['tuple', 'Tuple']

        tests = [
            # Alias                                    # Args                                               # Expected result
            ('generic[T1, bool, T2]',                  '[int, str]',                                        'generic[int, bool, str]'),
            ('generic[T1, bool, T2]',                  '[*tuple_type[int, str]]',                           'generic[int, bool, str]'),
        ]

        for alias_template, args_template, expected_template in tests:
            rendered_templates = template_replace(
                templates=[alias_template, args_template, expected_template],
                replacements={'generic': generics, 'tuple_type': tuple_types}
            )
            for alias_str, args_str, expected_str in rendered_templates:
                with self.subTest(alias=alias_str, args=args_str, expected=expected_str):
                    if expected_str == 'TypeError':
                        with self.assertRaises(TypeError):
                            eval(alias_str + args_str)
                    else:
                        self.assertEqual(
                            eval(alias_str + args_str),
                            eval(expected_str)
                        )

    def test_variadic_parameters(self):
        T1 = TypeVar('T1')
        T2 = TypeVar('T2')
        Ts = TypeVarTuple('Ts')

        class C(Generic[*Ts]): pass

        generics = ['C', 'tuple', 'Tuple']
        tuple_types = ['tuple', 'Tuple']

        tests = [
            # Alias                                    # Args                                            # Expected result
            ('generic[*Ts]',                           '[()]',                                           'generic[()]'),
            ('generic[*Ts]',                           '[int]',                                          'generic[int]'),
            ('generic[*Ts]',                           '[int, str]',                                     'generic[int, str]'),
            ('generic[*Ts]',                           '[*tuple_type[int]]',                             'generic[int]'),
            ('generic[*Ts]',                           '[*tuple_type[*Ts]]',                             'generic[*Ts]'),
            ('generic[*Ts]',                           '[*tuple_type[int, str]]',                        'generic[int, str]'),
            ('generic[*Ts]',                           '[str, *tuple_type[int, ...], bool]',             'generic[str, *tuple_type[int, ...], bool]'),
            ('generic[*Ts]',                           '[tuple_type[int, ...]]',                         'generic[tuple_type[int, ...]]'),
            ('generic[*Ts]',                           '[tuple_type[int, ...], tuple_type[str, ...]]',   'generic[tuple_type[int, ...], tuple_type[str, ...]]'),
            ('generic[*Ts]',                           '[*tuple_type[int, ...]]',                        'generic[*tuple_type[int, ...]]'),
            ('generic[*Ts]',                           '[*tuple_type[int, ...], *tuple_type[str, ...]]', 'TypeError'),

            ('generic[*Ts]',                           '[*Ts]',                                          'generic[*Ts]'),
            ('generic[*Ts]',                           '[T, *Ts]',                                       'generic[T, *Ts]'),
            ('generic[*Ts]',                           '[*Ts, T]',                                       'generic[*Ts, T]'),
            ('generic[T, *Ts]',                        '[()]',                                           'TypeError'),
            ('generic[T, *Ts]',                        '[int]',                                          'generic[int]'),
            ('generic[T, *Ts]',                        '[int, str]',                                     'generic[int, str]'),
            ('generic[T, *Ts]',                        '[int, str, bool]',                               'generic[int, str, bool]'),
            ('generic[list[T], *Ts]',                  '[()]',                                           'TypeError'),
            ('generic[list[T], *Ts]',                  '[int]',                                          'generic[list[int]]'),
            ('generic[list[T], *Ts]',                  '[int, str]',                                     'generic[list[int], str]'),
            ('generic[list[T], *Ts]',                  '[int, str, bool]',                               'generic[list[int], str, bool]'),

            ('generic[*Ts, T]',                        '[()]',                                           'TypeError'),
            ('generic[*Ts, T]',                        '[int]',                                          'generic[int]'),
            ('generic[*Ts, T]',                        '[int, str]',                                     'generic[int, str]'),
            ('generic[*Ts, T]',                        '[int, str, bool]',                               'generic[int, str, bool]'),
            ('generic[*Ts, list[T]]',                  '[()]',                                           'TypeError'),
            ('generic[*Ts, list[T]]',                  '[int]',                                          'generic[list[int]]'),
            ('generic[*Ts, list[T]]',                  '[int, str]',                                     'generic[int, list[str]]'),
            ('generic[*Ts, list[T]]',                  '[int, str, bool]',                               'generic[int, str, list[bool]]'),

            ('generic[T1, T2, *Ts]',                   '[()]',                                           'TypeError'),
            ('generic[T1, T2, *Ts]',                   '[int]',                                          'TypeError'),
            ('generic[T1, T2, *Ts]',                   '[int, str]',                                     'generic[int, str]'),
            ('generic[T1, T2, *Ts]',                   '[int, str, bool]',                               'generic[int, str, bool]'),
            ('generic[T1, T2, *Ts]',                   '[int, str, bool, bytes]',                        'generic[int, str, bool, bytes]'),

            ('generic[*Ts, T1, T2]',                   '[()]',                                           'TypeError'),
            ('generic[*Ts, T1, T2]',                   '[int]',                                          'TypeError'),
            ('generic[*Ts, T1, T2]',                   '[int, str]',                                     'generic[int, str]'),
            ('generic[*Ts, T1, T2]',                   '[int, str, bool]',                               'generic[int, str, bool]'),
            ('generic[*Ts, T1, T2]',                   '[int, str, bool, bytes]',                        'generic[int, str, bool, bytes]'),

            ('generic[T1, *Ts, T2]',                   '[()]',                                           'TypeError'),
            ('generic[T1, *Ts, T2]',                   '[int]',                                          'TypeError'),
            ('generic[T1, *Ts, T2]',                   '[int, str]',                                     'generic[int, str]'),
            ('generic[T1, *Ts, T2]',                   '[int, str, bool]',                               'generic[int, str, bool]'),
            ('generic[T1, *Ts, T2]',                   '[int, str, bool, bytes]',                        'generic[int, str, bool, bytes]'),

            ('generic[T, *Ts]',                        '[*tuple_type[int, ...]]',                        'generic[int, *tuple_type[int, ...]]'),
            ('generic[T, *Ts]',                        '[str, *tuple_type[int, ...]]',                   'generic[str, *tuple_type[int, ...]]'),
            ('generic[T, *Ts]',                        '[*tuple_type[int, ...], str]',                   'generic[int, *tuple_type[int, ...], str]'),
            ('generic[*Ts, T]',                        '[*tuple_type[int, ...]]',                        'generic[*tuple_type[int, ...], int]'),
            ('generic[*Ts, T]',                        '[str, *tuple_type[int, ...]]',                   'generic[str, *tuple_type[int, ...], int]'),
            ('generic[*Ts, T]',                        '[*tuple_type[int, ...], str]',                   'generic[*tuple_type[int, ...], str]'),
            ('generic[T1, *Ts, T2]',                   '[*tuple_type[int, ...]]',                        'generic[int, *tuple_type[int, ...], int]'),
            ('generic[T, str, *Ts]',                   '[*tuple_type[int, ...]]',                        'generic[int, str, *tuple_type[int, ...]]'),
            ('generic[*Ts, str, T]',                   '[*tuple_type[int, ...]]',                        'generic[*tuple_type[int, ...], str, int]'),
            ('generic[list[T], *Ts]',                  '[*tuple_type[int, ...]]',                        'generic[list[int], *tuple_type[int, ...]]'),
            ('generic[*Ts, list[T]]',                  '[*tuple_type[int, ...]]',                        'generic[*tuple_type[int, ...], list[int]]'),

            ('generic[T, *tuple_type[int, ...]]',      '[str]',                                          'generic[str, *tuple_type[int, ...]]'),
            ('generic[T1, T2, *tuple_type[int, ...]]', '[str, bool]',                                    'generic[str, bool, *tuple_type[int, ...]]'),
            ('generic[T1, *tuple_type[int, ...], T2]', '[str, bool]',                                    'generic[str, *tuple_type[int, ...], bool]'),
            ('generic[T1, *tuple_type[int, ...], T2]', '[str, bool, float]',                             'TypeError'),

            ('generic[T1, *tuple_type[T2, ...]]',      '[int, str]',                                     'generic[int, *tuple_type[str, ...]]'),
            ('generic[*tuple_type[T1, ...], T2]',      '[int, str]',                                     'generic[*tuple_type[int, ...], str]'),
            ('generic[T1, *tuple_type[generic[*Ts], ...]]', '[int, str, bool]',                          'generic[int, *tuple_type[generic[str, bool], ...]]'),
            ('generic[*tuple_type[generic[*Ts], ...], T1]', '[int, str, bool]',                          'generic[*tuple_type[generic[int, str], ...], bool]'),
        ]

        for alias_template, args_template, expected_template in tests:
            rendered_templates = template_replace(
                    templates=[alias_template, args_template, expected_template],
                    replacements={'generic': generics, 'tuple_type': tuple_types}
            )
            for alias_str, args_str, expected_str in rendered_templates:
                with self.subTest(alias=alias_str, args=args_str, expected=expected_str):
                    if expected_str == 'TypeError':
                        with self.assertRaises(TypeError):
                            eval(alias_str + args_str)
                    else:
                        self.assertEqual(
                            eval(alias_str + args_str),
                            eval(expected_str)
                        )



class UnpackTests(BaseTestCase):

    def test_accepts_single_type(self):
        (*tuple[int],)
        Unpack[Tuple[int]]

    def test_dir(self):
        dir_items = set(dir(Unpack[Tuple[int]]))
        for required_item in [
            '__args__', '__parameters__', '__origin__',
        ]:
            with self.subTest(required_item=required_item):
                self.assertIn(required_item, dir_items)

    def test_rejects_multiple_types(self):
        with self.assertRaises(TypeError):
            Unpack[Tuple[int], Tuple[str]]
        # We can't do the equivalent for `*` here -
        # *(Tuple[int], Tuple[str]) is just plain tuple unpacking,
        # which is valid.

    def test_rejects_multiple_parameterization(self):
        with self.assertRaises(TypeError):
            (*tuple[int],)[0][tuple[int]]
        with self.assertRaises(TypeError):
            Unpack[Tuple[int]][Tuple[int]]

    def test_cannot_be_called(self):
        with self.assertRaises(TypeError):
            Unpack()

    def test_usage_with_kwargs(self):
        Movie = TypedDict('Movie', {'name': str, 'year': int})
        def foo(**kwargs: Unpack[Movie]): ...
        self.assertEqual(repr(foo.__annotations__['kwargs']),
                         f"typing.Unpack[{__name__}.Movie]")

    def test_builtin_tuple(self):
        Ts = TypeVarTuple("Ts")

        class Old(Generic[*Ts]): ...
        class New[*Ts]: ...

        PartOld = Old[int, *Ts]
        self.assertEqual(PartOld[str].__args__, (int, str))
        self.assertEqual(PartOld[*tuple[str]].__args__, (int, str))
        self.assertEqual(PartOld[*Tuple[str]].__args__, (int, str))
        self.assertEqual(PartOld[Unpack[tuple[str]]].__args__, (int, str))
        self.assertEqual(PartOld[Unpack[Tuple[str]]].__args__, (int, str))

        PartNew = New[int, *Ts]
        self.assertEqual(PartNew[str].__args__, (int, str))
        self.assertEqual(PartNew[*tuple[str]].__args__, (int, str))
        self.assertEqual(PartNew[*Tuple[str]].__args__, (int, str))
        self.assertEqual(PartNew[Unpack[tuple[str]]].__args__, (int, str))
        self.assertEqual(PartNew[Unpack[Tuple[str]]].__args__, (int, str))

    def test_unpack_wrong_type(self):
        Ts = TypeVarTuple("Ts")
        class Gen[*Ts]: ...
        PartGen = Gen[int, *Ts]

        bad_unpack_param = re.escape("Unpack[...] must be used with a tuple type")
        with self.assertRaisesRegex(TypeError, bad_unpack_param):
            PartGen[Unpack[list[int]]]
        with self.assertRaisesRegex(TypeError, bad_unpack_param):
            PartGen[Unpack[List[int]]]


class TypeVarTupleTests(BaseTestCase):

    def assertEndsWith(self, string, tail):
        if not string.endswith(tail):
            self.fail(f"String {string!r} does not end with {tail!r}")

    def test_name(self):
        Ts = TypeVarTuple('Ts')
        self.assertEqual(Ts.__name__, 'Ts')
        Ts2 = TypeVarTuple('Ts2')
        self.assertEqual(Ts2.__name__, 'Ts2')

    def test_module(self):
        Ts = TypeVarTuple('Ts')
        self.assertEqual(Ts.__module__, __name__)

    def test_exec(self):
        ns = {}
        exec('from typing import TypeVarTuple; Ts = TypeVarTuple("Ts")', ns)
        Ts = ns['Ts']
        self.assertEqual(Ts.__name__, 'Ts')
        self.assertIs(Ts.__module__, None)

    def test_instance_is_equal_to_itself(self):
        Ts = TypeVarTuple('Ts')
        self.assertEqual(Ts, Ts)

    def test_different_instances_are_different(self):
        self.assertNotEqual(TypeVarTuple('Ts'), TypeVarTuple('Ts'))

    def test_instance_isinstance_of_typevartuple(self):
        Ts = TypeVarTuple('Ts')
        self.assertIsInstance(Ts, TypeVarTuple)

    def test_cannot_call_instance(self):
        Ts = TypeVarTuple('Ts')
        with self.assertRaises(TypeError):
            Ts()

    def test_unpacked_typevartuple_is_equal_to_itself(self):
        Ts = TypeVarTuple('Ts')
        self.assertEqual((*Ts,)[0], (*Ts,)[0])
        self.assertEqual(Unpack[Ts], Unpack[Ts])

    def test_parameterised_tuple_is_equal_to_itself(self):
        Ts = TypeVarTuple('Ts')
        self.assertEqual(tuple[*Ts], tuple[*Ts])
        self.assertEqual(Tuple[Unpack[Ts]], Tuple[Unpack[Ts]])

    def tests_tuple_arg_ordering_matters(self):
        Ts1 = TypeVarTuple('Ts1')
        Ts2 = TypeVarTuple('Ts2')
        self.assertNotEqual(
            tuple[*Ts1, *Ts2],
            tuple[*Ts2, *Ts1],
        )
        self.assertNotEqual(
            Tuple[Unpack[Ts1], Unpack[Ts2]],
            Tuple[Unpack[Ts2], Unpack[Ts1]],
        )

    def test_tuple_args_and_parameters_are_correct(self):
        Ts = TypeVarTuple('Ts')
        t1 = tuple[*Ts]
        self.assertEqual(t1.__args__, (*Ts,))
        self.assertEqual(t1.__parameters__, (Ts,))
        t2 = Tuple[Unpack[Ts]]
        self.assertEqual(t2.__args__, (Unpack[Ts],))
        self.assertEqual(t2.__parameters__, (Ts,))

    def test_var_substitution(self):
        Ts = TypeVarTuple('Ts')
        T = TypeVar('T')
        T2 = TypeVar('T2')
        class G1(Generic[*Ts]): pass
        class G2(Generic[Unpack[Ts]]): pass

        for A in G1, G2, Tuple, tuple:
            B = A[*Ts]
            self.assertEqual(B[()], A[()])
            self.assertEqual(B[float], A[float])
            self.assertEqual(B[float, str], A[float, str])

            C = A[Unpack[Ts]]
            self.assertEqual(C[()], A[()])
            self.assertEqual(C[float], A[float])
            self.assertEqual(C[float, str], A[float, str])

            D = list[A[*Ts]]
            self.assertEqual(D[()], list[A[()]])
            self.assertEqual(D[float], list[A[float]])
            self.assertEqual(D[float, str], list[A[float, str]])

            E = List[A[Unpack[Ts]]]
            self.assertEqual(E[()], List[A[()]])
            self.assertEqual(E[float], List[A[float]])
            self.assertEqual(E[float, str], List[A[float, str]])

            F = A[T, *Ts, T2]
            with self.assertRaises(TypeError):
                F[()]
            with self.assertRaises(TypeError):
                F[float]
            self.assertEqual(F[float, str], A[float, str])
            self.assertEqual(F[float, str, int], A[float, str, int])
            self.assertEqual(F[float, str, int, bytes], A[float, str, int, bytes])

            G = A[T, Unpack[Ts], T2]
            with self.assertRaises(TypeError):
                G[()]
            with self.assertRaises(TypeError):
                G[float]
            self.assertEqual(G[float, str], A[float, str])
            self.assertEqual(G[float, str, int], A[float, str, int])
            self.assertEqual(G[float, str, int, bytes], A[float, str, int, bytes])

            H = tuple[list[T], A[*Ts], list[T2]]
            with self.assertRaises(TypeError):
                H[()]
            with self.assertRaises(TypeError):
                H[float]
            if A != Tuple:
                self.assertEqual(H[float, str],
                                 tuple[list[float], A[()], list[str]])
            self.assertEqual(H[float, str, int],
                             tuple[list[float], A[str], list[int]])
            self.assertEqual(H[float, str, int, bytes],
                             tuple[list[float], A[str, int], list[bytes]])

            I = Tuple[List[T], A[Unpack[Ts]], List[T2]]
            with self.assertRaises(TypeError):
                I[()]
            with self.assertRaises(TypeError):
                I[float]
            if A != Tuple:
                self.assertEqual(I[float, str],
                                 Tuple[List[float], A[()], List[str]])
            self.assertEqual(I[float, str, int],
                             Tuple[List[float], A[str], List[int]])
            self.assertEqual(I[float, str, int, bytes],
                             Tuple[List[float], A[str, int], List[bytes]])

    def test_bad_var_substitution(self):
        Ts = TypeVarTuple('Ts')
        T = TypeVar('T')
        T2 = TypeVar('T2')
        class G1(Generic[*Ts]): pass
        class G2(Generic[Unpack[Ts]]): pass

        for A in G1, G2, Tuple, tuple:
            B = A[Ts]
            with self.assertRaises(TypeError):
                B[int, str]

            C = A[T, T2]
            with self.assertRaises(TypeError):
                C[*Ts]
            with self.assertRaises(TypeError):
                C[Unpack[Ts]]

            B = A[T, *Ts, str, T2]
            with self.assertRaises(TypeError):
                B[int, *Ts]
            with self.assertRaises(TypeError):
                B[int, *Ts, *Ts]

            C = A[T, Unpack[Ts], str, T2]
            with self.assertRaises(TypeError):
                C[int, Unpack[Ts]]
            with self.assertRaises(TypeError):
                C[int, Unpack[Ts], Unpack[Ts]]

    def test_repr_is_correct(self):
        Ts = TypeVarTuple('Ts')

        class G1(Generic[*Ts]): pass
        class G2(Generic[Unpack[Ts]]): pass

        self.assertEqual(repr(Ts), 'Ts')

        self.assertEqual(repr((*Ts,)[0]), 'typing.Unpack[Ts]')
        self.assertEqual(repr(Unpack[Ts]), 'typing.Unpack[Ts]')

        self.assertEqual(repr(tuple[*Ts]), 'tuple[typing.Unpack[Ts]]')
        self.assertEqual(repr(Tuple[Unpack[Ts]]), 'typing.Tuple[typing.Unpack[Ts]]')

        self.assertEqual(repr(*tuple[*Ts]), '*tuple[typing.Unpack[Ts]]')
        self.assertEqual(repr(Unpack[Tuple[Unpack[Ts]]]), 'typing.Unpack[typing.Tuple[typing.Unpack[Ts]]]')

    def test_variadic_class_repr_is_correct(self):
        Ts = TypeVarTuple('Ts')
        class A(Generic[*Ts]): pass
        class B(Generic[Unpack[Ts]]): pass

        self.assertEndsWith(repr(A[()]), 'A[()]')
        self.assertEndsWith(repr(B[()]), 'B[()]')
        self.assertEndsWith(repr(A[float]), 'A[float]')
        self.assertEndsWith(repr(B[float]), 'B[float]')
        self.assertEndsWith(repr(A[float, str]), 'A[float, str]')
        self.assertEndsWith(repr(B[float, str]), 'B[float, str]')

        self.assertEndsWith(repr(A[*tuple[int, ...]]),
                            'A[*tuple[int, ...]]')
        self.assertEndsWith(repr(B[Unpack[Tuple[int, ...]]]),
                            'B[typing.Unpack[typing.Tuple[int, ...]]]')

        self.assertEndsWith(repr(A[float, *tuple[int, ...]]),
                            'A[float, *tuple[int, ...]]')
        self.assertEndsWith(repr(A[float, Unpack[Tuple[int, ...]]]),
                            'A[float, typing.Unpack[typing.Tuple[int, ...]]]')

        self.assertEndsWith(repr(A[*tuple[int, ...], str]),
                            'A[*tuple[int, ...], str]')
        self.assertEndsWith(repr(B[Unpack[Tuple[int, ...]], str]),
                            'B[typing.Unpack[typing.Tuple[int, ...]], str]')

        self.assertEndsWith(repr(A[float, *tuple[int, ...], str]),
                            'A[float, *tuple[int, ...], str]')
        self.assertEndsWith(repr(B[float, Unpack[Tuple[int, ...]], str]),
                            'B[float, typing.Unpack[typing.Tuple[int, ...]], str]')

    def test_variadic_class_alias_repr_is_correct(self):
        Ts = TypeVarTuple('Ts')
        class A(Generic[Unpack[Ts]]): pass

        B = A[*Ts]
        self.assertEndsWith(repr(B), 'A[typing.Unpack[Ts]]')
        self.assertEndsWith(repr(B[()]), 'A[()]')
        self.assertEndsWith(repr(B[float]), 'A[float]')
        self.assertEndsWith(repr(B[float, str]), 'A[float, str]')

        C = A[Unpack[Ts]]
        self.assertEndsWith(repr(C), 'A[typing.Unpack[Ts]]')
        self.assertEndsWith(repr(C[()]), 'A[()]')
        self.assertEndsWith(repr(C[float]), 'A[float]')
        self.assertEndsWith(repr(C[float, str]), 'A[float, str]')

        D = A[*Ts, int]
        self.assertEndsWith(repr(D), 'A[typing.Unpack[Ts], int]')
        self.assertEndsWith(repr(D[()]), 'A[int]')
        self.assertEndsWith(repr(D[float]), 'A[float, int]')
        self.assertEndsWith(repr(D[float, str]), 'A[float, str, int]')

        E = A[Unpack[Ts], int]
        self.assertEndsWith(repr(E), 'A[typing.Unpack[Ts], int]')
        self.assertEndsWith(repr(E[()]), 'A[int]')
        self.assertEndsWith(repr(E[float]), 'A[float, int]')
        self.assertEndsWith(repr(E[float, str]), 'A[float, str, int]')

        F = A[int, *Ts]
        self.assertEndsWith(repr(F), 'A[int, typing.Unpack[Ts]]')
        self.assertEndsWith(repr(F[()]), 'A[int]')
        self.assertEndsWith(repr(F[float]), 'A[int, float]')
        self.assertEndsWith(repr(F[float, str]), 'A[int, float, str]')

        G = A[int, Unpack[Ts]]
        self.assertEndsWith(repr(G), 'A[int, typing.Unpack[Ts]]')
        self.assertEndsWith(repr(G[()]), 'A[int]')
        self.assertEndsWith(repr(G[float]), 'A[int, float]')
        self.assertEndsWith(repr(G[float, str]), 'A[int, float, str]')

        H = A[int, *Ts, str]
        self.assertEndsWith(repr(H), 'A[int, typing.Unpack[Ts], str]')
        self.assertEndsWith(repr(H[()]), 'A[int, str]')
        self.assertEndsWith(repr(H[float]), 'A[int, float, str]')
        self.assertEndsWith(repr(H[float, str]), 'A[int, float, str, str]')

        I = A[int, Unpack[Ts], str]
        self.assertEndsWith(repr(I), 'A[int, typing.Unpack[Ts], str]')
        self.assertEndsWith(repr(I[()]), 'A[int, str]')
        self.assertEndsWith(repr(I[float]), 'A[int, float, str]')
        self.assertEndsWith(repr(I[float, str]), 'A[int, float, str, str]')

        J = A[*Ts, *tuple[str, ...]]
        self.assertEndsWith(repr(J), 'A[typing.Unpack[Ts], *tuple[str, ...]]')
        self.assertEndsWith(repr(J[()]), 'A[*tuple[str, ...]]')
        self.assertEndsWith(repr(J[float]), 'A[float, *tuple[str, ...]]')
        self.assertEndsWith(repr(J[float, str]), 'A[float, str, *tuple[str, ...]]')

        K = A[Unpack[Ts], Unpack[Tuple[str, ...]]]
        self.assertEndsWith(repr(K), 'A[typing.Unpack[Ts], typing.Unpack[typing.Tuple[str, ...]]]')
        self.assertEndsWith(repr(K[()]), 'A[typing.Unpack[typing.Tuple[str, ...]]]')
        self.assertEndsWith(repr(K[float]), 'A[float, typing.Unpack[typing.Tuple[str, ...]]]')
        self.assertEndsWith(repr(K[float, str]), 'A[float, str, typing.Unpack[typing.Tuple[str, ...]]]')

    def test_cannot_subclass(self):
        with self.assertRaisesRegex(TypeError, NOT_A_BASE_TYPE % 'TypeVarTuple'):
            class C(TypeVarTuple): pass
        Ts = TypeVarTuple('Ts')
        with self.assertRaisesRegex(TypeError,
                CANNOT_SUBCLASS_INSTANCE % 'TypeVarTuple'):
            class D(Ts): pass
        with self.assertRaisesRegex(TypeError, CANNOT_SUBCLASS_TYPE):
            class E(type(Unpack)): pass
        with self.assertRaisesRegex(TypeError, CANNOT_SUBCLASS_TYPE):
            class F(type(*Ts)): pass
        with self.assertRaisesRegex(TypeError, CANNOT_SUBCLASS_TYPE):
            class G(type(Unpack[Ts])): pass
        with self.assertRaisesRegex(TypeError,
                                    r'Cannot subclass typing\.Unpack'):
            class H(Unpack): pass
        with self.assertRaisesRegex(TypeError, r'Cannot subclass typing.Unpack\[Ts\]'):
            class I(*Ts): pass
        with self.assertRaisesRegex(TypeError, r'Cannot subclass typing.Unpack\[Ts\]'):
            class J(Unpack[Ts]): pass

    def test_variadic_class_args_are_correct(self):
        T = TypeVar('T')
        Ts = TypeVarTuple('Ts')
        class A(Generic[*Ts]): pass
        class B(Generic[Unpack[Ts]]): pass

        C = A[()]
        D = B[()]
        self.assertEqual(C.__args__, ())
        self.assertEqual(D.__args__, ())

        E = A[int]
        F = B[int]
        self.assertEqual(E.__args__, (int,))
        self.assertEqual(F.__args__, (int,))

        G = A[int, str]
        H = B[int, str]
        self.assertEqual(G.__args__, (int, str))
        self.assertEqual(H.__args__, (int, str))

        I = A[T]
        J = B[T]
        self.assertEqual(I.__args__, (T,))
        self.assertEqual(J.__args__, (T,))

        K = A[*Ts]
        L = B[Unpack[Ts]]
        self.assertEqual(K.__args__, (*Ts,))
        self.assertEqual(L.__args__, (Unpack[Ts],))

        M = A[T, *Ts]
        N = B[T, Unpack[Ts]]
        self.assertEqual(M.__args__, (T, *Ts))
        self.assertEqual(N.__args__, (T, Unpack[Ts]))

        O = A[*Ts, T]
        P = B[Unpack[Ts], T]
        self.assertEqual(O.__args__, (*Ts, T))
        self.assertEqual(P.__args__, (Unpack[Ts], T))

    def test_variadic_class_origin_is_correct(self):
        Ts = TypeVarTuple('Ts')

        class C(Generic[*Ts]): pass
        self.assertIs(C[int].__origin__, C)
        self.assertIs(C[T].__origin__, C)
        self.assertIs(C[Unpack[Ts]].__origin__, C)

        class D(Generic[Unpack[Ts]]): pass
        self.assertIs(D[int].__origin__, D)
        self.assertIs(D[T].__origin__, D)
        self.assertIs(D[Unpack[Ts]].__origin__, D)

    def test_get_type_hints_on_unpack_args(self):
        Ts = TypeVarTuple('Ts')

        def func1(*args: *Ts): pass
        self.assertEqual(gth(func1), {'args': Unpack[Ts]})

        def func2(*args: *tuple[int, str]): pass
        self.assertEqual(gth(func2), {'args': Unpack[tuple[int, str]]})

        class CustomVariadic(Generic[*Ts]): pass

        def func3(*args: *CustomVariadic[int, str]): pass
        self.assertEqual(gth(func3), {'args': Unpack[CustomVariadic[int, str]]})

    def test_get_type_hints_on_unpack_args_string(self):
        Ts = TypeVarTuple('Ts')

        def func1(*args: '*Ts'): pass
        self.assertEqual(gth(func1, localns={'Ts': Ts}),
                        {'args': Unpack[Ts]})

        def func2(*args: '*tuple[int, str]'): pass
        self.assertEqual(gth(func2), {'args': Unpack[tuple[int, str]]})

        class CustomVariadic(Generic[*Ts]): pass

        def func3(*args: '*CustomVariadic[int, str]'): pass
        self.assertEqual(gth(func3, localns={'CustomVariadic': CustomVariadic}),
                         {'args': Unpack[CustomVariadic[int, str]]})

    def test_tuple_args_are_correct(self):
        Ts = TypeVarTuple('Ts')

        self.assertEqual(tuple[*Ts].__args__, (*Ts,))
        self.assertEqual(Tuple[Unpack[Ts]].__args__, (Unpack[Ts],))

        self.assertEqual(tuple[*Ts, int].__args__, (*Ts, int))
        self.assertEqual(Tuple[Unpack[Ts], int].__args__, (Unpack[Ts], int))

        self.assertEqual(tuple[int, *Ts].__args__, (int, *Ts))
        self.assertEqual(Tuple[int, Unpack[Ts]].__args__, (int, Unpack[Ts]))

        self.assertEqual(tuple[int, *Ts, str].__args__,
                         (int, *Ts, str))
        self.assertEqual(Tuple[int, Unpack[Ts], str].__args__,
                         (int, Unpack[Ts], str))

        self.assertEqual(tuple[*Ts, int].__args__, (*Ts, int))
        self.assertEqual(Tuple[Unpack[Ts]].__args__, (Unpack[Ts],))

    def test_callable_args_are_correct(self):
        Ts = TypeVarTuple('Ts')
        Ts1 = TypeVarTuple('Ts1')
        Ts2 = TypeVarTuple('Ts2')

        # TypeVarTuple in the arguments

        a = Callable[[*Ts], None]
        b = Callable[[Unpack[Ts]], None]
        self.assertEqual(a.__args__, (*Ts, type(None)))
        self.assertEqual(b.__args__, (Unpack[Ts], type(None)))

        c = Callable[[int, *Ts], None]
        d = Callable[[int, Unpack[Ts]], None]
        self.assertEqual(c.__args__, (int, *Ts, type(None)))
        self.assertEqual(d.__args__, (int, Unpack[Ts], type(None)))

        e = Callable[[*Ts, int], None]
        f = Callable[[Unpack[Ts], int], None]
        self.assertEqual(e.__args__, (*Ts, int, type(None)))
        self.assertEqual(f.__args__, (Unpack[Ts], int, type(None)))

        g = Callable[[str, *Ts, int], None]
        h = Callable[[str, Unpack[Ts], int], None]
        self.assertEqual(g.__args__, (str, *Ts, int, type(None)))
        self.assertEqual(h.__args__, (str, Unpack[Ts], int, type(None)))

        # TypeVarTuple as the return

        i = Callable[[None], *Ts]
        j = Callable[[None], Unpack[Ts]]
        self.assertEqual(i.__args__, (type(None), *Ts))
        self.assertEqual(j.__args__, (type(None), Unpack[Ts]))

        k = Callable[[None], tuple[int, *Ts]]
        l = Callable[[None], Tuple[int, Unpack[Ts]]]
        self.assertEqual(k.__args__, (type(None), tuple[int, *Ts]))
        self.assertEqual(l.__args__, (type(None), Tuple[int, Unpack[Ts]]))

        m = Callable[[None], tuple[*Ts, int]]
        n = Callable[[None], Tuple[Unpack[Ts], int]]
        self.assertEqual(m.__args__, (type(None), tuple[*Ts, int]))
        self.assertEqual(n.__args__, (type(None), Tuple[Unpack[Ts], int]))

        o = Callable[[None], tuple[str, *Ts, int]]
        p = Callable[[None], Tuple[str, Unpack[Ts], int]]
        self.assertEqual(o.__args__, (type(None), tuple[str, *Ts, int]))
        self.assertEqual(p.__args__, (type(None), Tuple[str, Unpack[Ts], int]))

        # TypeVarTuple in both

        q = Callable[[*Ts], *Ts]
        r = Callable[[Unpack[Ts]], Unpack[Ts]]
        self.assertEqual(q.__args__, (*Ts, *Ts))
        self.assertEqual(r.__args__, (Unpack[Ts], Unpack[Ts]))

        s = Callable[[*Ts1], *Ts2]
        u = Callable[[Unpack[Ts1]], Unpack[Ts2]]
        self.assertEqual(s.__args__, (*Ts1, *Ts2))
        self.assertEqual(u.__args__, (Unpack[Ts1], Unpack[Ts2]))

    def test_variadic_class_with_duplicate_typevartuples_fails(self):
        Ts1 = TypeVarTuple('Ts1')
        Ts2 = TypeVarTuple('Ts2')

        with self.assertRaises(TypeError):
            class C(Generic[*Ts1, *Ts1]): pass
        with self.assertRaises(TypeError):
            class D(Generic[Unpack[Ts1], Unpack[Ts1]]): pass

        with self.assertRaises(TypeError):
            class E(Generic[*Ts1, *Ts2, *Ts1]): pass
        with self.assertRaises(TypeError):
            class F(Generic[Unpack[Ts1], Unpack[Ts2], Unpack[Ts1]]): pass

    def test_type_concatenation_in_variadic_class_argument_list_succeeds(self):
        Ts = TypeVarTuple('Ts')
        class C(Generic[Unpack[Ts]]): pass

        C[int, *Ts]
        C[int, Unpack[Ts]]

        C[*Ts, int]
        C[Unpack[Ts], int]

        C[int, *Ts, str]
        C[int, Unpack[Ts], str]

        C[int, bool, *Ts, float, str]
        C[int, bool, Unpack[Ts], float, str]

    def test_type_concatenation_in_tuple_argument_list_succeeds(self):
        Ts = TypeVarTuple('Ts')

        tuple[int, *Ts]
        tuple[*Ts, int]
        tuple[int, *Ts, str]
        tuple[int, bool, *Ts, float, str]

        Tuple[int, Unpack[Ts]]
        Tuple[Unpack[Ts], int]
        Tuple[int, Unpack[Ts], str]
        Tuple[int, bool, Unpack[Ts], float, str]

    def test_variadic_class_definition_using_packed_typevartuple_fails(self):
        Ts = TypeVarTuple('Ts')
        with self.assertRaises(TypeError):
            class C(Generic[Ts]): pass

    def test_variadic_class_definition_using_concrete_types_fails(self):
        Ts = TypeVarTuple('Ts')
        with self.assertRaises(TypeError):
            class F(Generic[*Ts, int]): pass
        with self.assertRaises(TypeError):
            class E(Generic[Unpack[Ts], int]): pass

    def test_variadic_class_with_2_typevars_accepts_2_or_more_args(self):
        Ts = TypeVarTuple('Ts')
        T1 = TypeVar('T1')
        T2 = TypeVar('T2')

        class A(Generic[T1, T2, *Ts]): pass
        A[int, str]
        A[int, str, float]
        A[int, str, float, bool]

        class B(Generic[T1, T2, Unpack[Ts]]): pass
        B[int, str]
        B[int, str, float]
        B[int, str, float, bool]

        class C(Generic[T1, *Ts, T2]): pass
        C[int, str]
        C[int, str, float]
        C[int, str, float, bool]

        class D(Generic[T1, Unpack[Ts], T2]): pass
        D[int, str]
        D[int, str, float]
        D[int, str, float, bool]

        class E(Generic[*Ts, T1, T2]): pass
        E[int, str]
        E[int, str, float]
        E[int, str, float, bool]

        class F(Generic[Unpack[Ts], T1, T2]): pass
        F[int, str]
        F[int, str, float]
        F[int, str, float, bool]

    def test_variadic_args_annotations_are_correct(self):
        Ts = TypeVarTuple('Ts')

        def f(*args: Unpack[Ts]): pass
        def g(*args: *Ts): pass
        self.assertEqual(f.__annotations__, {'args': Unpack[Ts]})
        self.assertEqual(g.__annotations__, {'args': (*Ts,)[0]})

    def test_variadic_args_with_ellipsis_annotations_are_correct(self):
        def a(*args: *tuple[int, ...]): pass
        self.assertEqual(a.__annotations__,
                         {'args': (*tuple[int, ...],)[0]})

        def b(*args: Unpack[Tuple[int, ...]]): pass
        self.assertEqual(b.__annotations__,
                         {'args': Unpack[Tuple[int, ...]]})

    def test_concatenation_in_variadic_args_annotations_are_correct(self):
        Ts = TypeVarTuple('Ts')

        # Unpacking using `*`, native `tuple` type

        def a(*args: *tuple[int, *Ts]): pass
        self.assertEqual(
            a.__annotations__,
            {'args': (*tuple[int, *Ts],)[0]},
        )

        def b(*args: *tuple[*Ts, int]): pass
        self.assertEqual(
            b.__annotations__,
            {'args': (*tuple[*Ts, int],)[0]},
        )

        def c(*args: *tuple[str, *Ts, int]): pass
        self.assertEqual(
            c.__annotations__,
            {'args': (*tuple[str, *Ts, int],)[0]},
        )

        def d(*args: *tuple[int, bool, *Ts, float, str]): pass
        self.assertEqual(
            d.__annotations__,
            {'args': (*tuple[int, bool, *Ts, float, str],)[0]},
        )

        # Unpacking using `Unpack`, `Tuple` type from typing.py

        def e(*args: Unpack[Tuple[int, Unpack[Ts]]]): pass
        self.assertEqual(
            e.__annotations__,
            {'args': Unpack[Tuple[int, Unpack[Ts]]]},
        )

        def f(*args: Unpack[Tuple[Unpack[Ts], int]]): pass
        self.assertEqual(
            f.__annotations__,
            {'args': Unpack[Tuple[Unpack[Ts], int]]},
        )

        def g(*args: Unpack[Tuple[str, Unpack[Ts], int]]): pass
        self.assertEqual(
            g.__annotations__,
            {'args': Unpack[Tuple[str, Unpack[Ts], int]]},
        )

        def h(*args: Unpack[Tuple[int, bool, Unpack[Ts], float, str]]): pass
        self.assertEqual(
            h.__annotations__,
            {'args': Unpack[Tuple[int, bool, Unpack[Ts], float, str]]},
        )

    def test_variadic_class_same_args_results_in_equalty(self):
        Ts = TypeVarTuple('Ts')
        class C(Generic[*Ts]): pass
        class D(Generic[Unpack[Ts]]): pass

        self.assertEqual(C[int], C[int])
        self.assertEqual(D[int], D[int])

        Ts1 = TypeVarTuple('Ts1')
        Ts2 = TypeVarTuple('Ts2')

        self.assertEqual(
            C[*Ts1],
            C[*Ts1],
        )
        self.assertEqual(
            D[Unpack[Ts1]],
            D[Unpack[Ts1]],
        )

        self.assertEqual(
            C[*Ts1, *Ts2],
            C[*Ts1, *Ts2],
        )
        self.assertEqual(
            D[Unpack[Ts1], Unpack[Ts2]],
            D[Unpack[Ts1], Unpack[Ts2]],
        )

        self.assertEqual(
            C[int, *Ts1, *Ts2],
            C[int, *Ts1, *Ts2],
        )
        self.assertEqual(
            D[int, Unpack[Ts1], Unpack[Ts2]],
            D[int, Unpack[Ts1], Unpack[Ts2]],
        )

    def test_variadic_class_arg_ordering_matters(self):
        Ts = TypeVarTuple('Ts')
        class C(Generic[*Ts]): pass
        class D(Generic[Unpack[Ts]]): pass

        self.assertNotEqual(
            C[int, str],
            C[str, int],
        )
        self.assertNotEqual(
            D[int, str],
            D[str, int],
        )

        Ts1 = TypeVarTuple('Ts1')
        Ts2 = TypeVarTuple('Ts2')

        self.assertNotEqual(
            C[*Ts1, *Ts2],
            C[*Ts2, *Ts1],
        )
        self.assertNotEqual(
            D[Unpack[Ts1], Unpack[Ts2]],
            D[Unpack[Ts2], Unpack[Ts1]],
        )

    def test_variadic_class_arg_typevartuple_identity_matters(self):
        Ts = TypeVarTuple('Ts')
        Ts1 = TypeVarTuple('Ts1')
        Ts2 = TypeVarTuple('Ts2')

        class C(Generic[*Ts]): pass
        class D(Generic[Unpack[Ts]]): pass

        self.assertNotEqual(C[*Ts1], C[*Ts2])
        self.assertNotEqual(D[Unpack[Ts1]], D[Unpack[Ts2]])


class TypeVarTuplePicklingTests(BaseTestCase):
    # These are slightly awkward tests to run, because TypeVarTuples are only
    # picklable if defined in the global scope. We therefore need to push
    # various things defined in these tests into the global scope with `global`
    # statements at the start of each test.

    @all_pickle_protocols
    def test_pickling_then_unpickling_results_in_same_identity(self, proto):
        global global_Ts1  # See explanation at start of class.
        global_Ts1 = TypeVarTuple('global_Ts1')
        global_Ts2 = pickle.loads(pickle.dumps(global_Ts1, proto))
        self.assertIs(global_Ts1, global_Ts2)

    @all_pickle_protocols
    def test_pickling_then_unpickling_unpacked_results_in_same_identity(self, proto):
        global global_Ts  # See explanation at start of class.
        global_Ts = TypeVarTuple('global_Ts')

        unpacked1 = (*global_Ts,)[0]
        unpacked2 = pickle.loads(pickle.dumps(unpacked1, proto))
        self.assertIs(unpacked1, unpacked2)

        unpacked3 = Unpack[global_Ts]
        unpacked4 = pickle.loads(pickle.dumps(unpacked3, proto))
        self.assertIs(unpacked3, unpacked4)

    @all_pickle_protocols
    def test_pickling_then_unpickling_tuple_with_typevartuple_equality(
            self, proto
    ):
        global global_T, global_Ts  # See explanation at start of class.
        global_T = TypeVar('global_T')
        global_Ts = TypeVarTuple('global_Ts')

        tuples = [
            tuple[*global_Ts],
            Tuple[Unpack[global_Ts]],

            tuple[T, *global_Ts],
            Tuple[T, Unpack[global_Ts]],

            tuple[int, *global_Ts],
            Tuple[int, Unpack[global_Ts]],
        ]
        for t in tuples:
            t2 = pickle.loads(pickle.dumps(t, proto))
            self.assertEqual(t, t2)


class UnionTests(BaseTestCase):

    def test_basics(self):
        u = Union[int, float]
        self.assertNotEqual(u, Union)

    def test_subclass_error(self):
        with self.assertRaises(TypeError):
            issubclass(int, Union)
        with self.assertRaises(TypeError):
            issubclass(Union, int)
        with self.assertRaises(TypeError):
            issubclass(Union[int, str], int)

    def test_union_any(self):
        u = Union[Any]
        self.assertEqual(u, Any)
        u1 = Union[int, Any]
        u2 = Union[Any, int]
        u3 = Union[Any, object]
        self.assertEqual(u1, u2)
        self.assertNotEqual(u1, Any)
        self.assertNotEqual(u2, Any)
        self.assertNotEqual(u3, Any)

    def test_union_object(self):
        u = Union[object]
        self.assertEqual(u, object)
        u1 = Union[int, object]
        u2 = Union[object, int]
        self.assertEqual(u1, u2)
        self.assertNotEqual(u1, object)
        self.assertNotEqual(u2, object)

    def test_unordered(self):
        u1 = Union[int, float]
        u2 = Union[float, int]
        self.assertEqual(u1, u2)

    def test_single_class_disappears(self):
        t = Union[Employee]
        self.assertIs(t, Employee)

    def test_base_class_kept(self):
        u = Union[Employee, Manager]
        self.assertNotEqual(u, Employee)
        self.assertIn(Employee, u.__args__)
        self.assertIn(Manager, u.__args__)

    def test_union_union(self):
        u = Union[int, float]
        v = Union[u, Employee]
        self.assertEqual(v, Union[int, float, Employee])

    def test_union_of_unhashable(self):
        class UnhashableMeta(type):
            __hash__ = None

        class A(metaclass=UnhashableMeta): ...
        class B(metaclass=UnhashableMeta): ...

        self.assertEqual(Union[A, B].__args__, (A, B))
        union1 = Union[A, B]
        with self.assertRaises(TypeError):
            hash(union1)

        union2 = Union[int, B]
        with self.assertRaises(TypeError):
            hash(union2)

        union3 = Union[A, int]
        with self.assertRaises(TypeError):
            hash(union3)

    def test_repr(self):
        self.assertEqual(repr(Union), 'typing.Union')
        u = Union[Employee, int]
        self.assertEqual(repr(u), 'typing.Union[%s.Employee, int]' % __name__)
        u = Union[int, Employee]
        self.assertEqual(repr(u), 'typing.Union[int, %s.Employee]' % __name__)
        T = TypeVar('T')
        u = Union[T, int][int]
        self.assertEqual(repr(u), repr(int))
        u = Union[List[int], int]
        self.assertEqual(repr(u), 'typing.Union[typing.List[int], int]')
        u = Union[list[int], dict[str, float]]
        self.assertEqual(repr(u), 'typing.Union[list[int], dict[str, float]]')
        u = Union[int | float]
        self.assertEqual(repr(u), 'typing.Union[int, float]')

        u = Union[None, str]
        self.assertEqual(repr(u), 'typing.Optional[str]')
        u = Union[str, None]
        self.assertEqual(repr(u), 'typing.Optional[str]')
        u = Union[None, str, int]
        self.assertEqual(repr(u), 'typing.Union[NoneType, str, int]')
        u = Optional[str]
        self.assertEqual(repr(u), 'typing.Optional[str]')

    def test_dir(self):
        dir_items = set(dir(Union[str, int]))
        for required_item in [
            '__args__', '__parameters__', '__origin__',
        ]:
            with self.subTest(required_item=required_item):
                self.assertIn(required_item, dir_items)

    def test_cannot_subclass(self):
        with self.assertRaisesRegex(TypeError,
                r'Cannot subclass typing\.Union'):
            class C(Union):
                pass
        with self.assertRaisesRegex(TypeError, CANNOT_SUBCLASS_TYPE):
            class D(type(Union)):
                pass
        with self.assertRaisesRegex(TypeError,
                r'Cannot subclass typing\.Union\[int, str\]'):
            class E(Union[int, str]):
                pass

    def test_cannot_instantiate(self):
        with self.assertRaises(TypeError):
            Union()
        with self.assertRaises(TypeError):
            type(Union)()
        u = Union[int, float]
        with self.assertRaises(TypeError):
            u()
        with self.assertRaises(TypeError):
            type(u)()

    def test_union_generalization(self):
        self.assertFalse(Union[str, typing.Iterable[int]] == str)
        self.assertFalse(Union[str, typing.Iterable[int]] == typing.Iterable[int])
        self.assertIn(str, Union[str, typing.Iterable[int]].__args__)
        self.assertIn(typing.Iterable[int], Union[str, typing.Iterable[int]].__args__)

    def test_union_compare_other(self):
        self.assertNotEqual(Union, object)
        self.assertNotEqual(Union, Any)
        self.assertNotEqual(ClassVar, Union)
        self.assertNotEqual(Optional, Union)
        self.assertNotEqual([None], Optional)
        self.assertNotEqual(Optional, typing.Mapping)
        self.assertNotEqual(Optional[typing.MutableMapping], Union)

    def test_optional(self):
        o = Optional[int]
        u = Union[int, None]
        self.assertEqual(o, u)

    def test_empty(self):
        with self.assertRaises(TypeError):
            Union[()]

    def test_no_eval_union(self):
        u = Union[int, str]
        def f(x: u): ...
        self.assertIs(get_type_hints(f)['x'], u)

    def test_function_repr_union(self):
        def fun() -> int: ...
        self.assertEqual(repr(Union[fun, int]), 'typing.Union[fun, int]')

    def test_union_str_pattern(self):
        # Shouldn't crash; see http://bugs.python.org/issue25390
        A = Union[str, Pattern]
        A

    def test_etree(self):
        # See https://github.com/python/typing/issues/229
        # (Only relevant for Python 2.)
        from xml.etree.ElementTree import Element

        Union[Element, str]  # Shouldn't crash

        def Elem(*args):
            return Element(*args)

        Union[Elem, str]  # Nor should this

    def test_union_of_literals(self):
        self.assertEqual(Union[Literal[1], Literal[2]].__args__,
                         (Literal[1], Literal[2]))
        self.assertEqual(Union[Literal[1], Literal[1]],
                         Literal[1])

        self.assertEqual(Union[Literal[False], Literal[0]].__args__,
                         (Literal[False], Literal[0]))
        self.assertEqual(Union[Literal[True], Literal[1]].__args__,
                         (Literal[True], Literal[1]))

        import enum
        class Ints(enum.IntEnum):
            A = 0
            B = 1

        self.assertEqual(Union[Literal[Ints.A], Literal[Ints.A]],
                         Literal[Ints.A])
        self.assertEqual(Union[Literal[Ints.B], Literal[Ints.B]],
                         Literal[Ints.B])

        self.assertEqual(Union[Literal[Ints.A], Literal[Ints.B]].__args__,
                         (Literal[Ints.A], Literal[Ints.B]))

        self.assertEqual(Union[Literal[0], Literal[Ints.A], Literal[False]].__args__,
                         (Literal[0], Literal[Ints.A], Literal[False]))
        self.assertEqual(Union[Literal[1], Literal[Ints.B], Literal[True]].__args__,
                         (Literal[1], Literal[Ints.B], Literal[True]))


class TupleTests(BaseTestCase):

    def test_basics(self):
        with self.assertRaises(TypeError):
            issubclass(Tuple, Tuple[int, str])
        with self.assertRaises(TypeError):
            issubclass(tuple, Tuple[int, str])

        class TP(tuple): ...
        self.assertIsSubclass(tuple, Tuple)
        self.assertIsSubclass(TP, Tuple)

    def test_equality(self):
        self.assertEqual(Tuple[int], Tuple[int])
        self.assertEqual(Tuple[int, ...], Tuple[int, ...])
        self.assertNotEqual(Tuple[int], Tuple[int, int])
        self.assertNotEqual(Tuple[int], Tuple[int, ...])

    def test_tuple_subclass(self):
        class MyTuple(tuple):
            pass
        self.assertIsSubclass(MyTuple, Tuple)
        self.assertIsSubclass(Tuple, Tuple)
        self.assertIsSubclass(tuple, Tuple)

    def test_tuple_instance_type_error(self):
        with self.assertRaises(TypeError):
            isinstance((0, 0), Tuple[int, int])
        self.assertIsInstance((0, 0), Tuple)

    def test_repr(self):
        self.assertEqual(repr(Tuple), 'typing.Tuple')
        self.assertEqual(repr(Tuple[()]), 'typing.Tuple[()]')
        self.assertEqual(repr(Tuple[int, float]), 'typing.Tuple[int, float]')
        self.assertEqual(repr(Tuple[int, ...]), 'typing.Tuple[int, ...]')
        self.assertEqual(repr(Tuple[list[int]]), 'typing.Tuple[list[int]]')

    def test_errors(self):
        with self.assertRaises(TypeError):
            issubclass(42, Tuple)
        with self.assertRaises(TypeError):
            issubclass(42, Tuple[int])


class BaseCallableTests:

    def test_self_subclass(self):
        Callable = self.Callable
        with self.assertRaises(TypeError):
            issubclass(types.FunctionType, Callable[[int], int])
        self.assertIsSubclass(types.FunctionType, Callable)
        self.assertIsSubclass(Callable, Callable)

    def test_eq_hash(self):
        Callable = self.Callable
        C = Callable[[int], int]
        self.assertEqual(C, Callable[[int], int])
        self.assertEqual(len({C, Callable[[int], int]}), 1)
        self.assertNotEqual(C, Callable[[int], str])
        self.assertNotEqual(C, Callable[[str], int])
        self.assertNotEqual(C, Callable[[int, int], int])
        self.assertNotEqual(C, Callable[[], int])
        self.assertNotEqual(C, Callable[..., int])
        self.assertNotEqual(C, Callable)

    def test_dir(self):
        Callable = self.Callable
        dir_items = set(dir(Callable[..., int]))
        for required_item in [
            '__args__', '__parameters__', '__origin__',
        ]:
            with self.subTest(required_item=required_item):
                self.assertIn(required_item, dir_items)

    def test_cannot_instantiate(self):
        Callable = self.Callable
        with self.assertRaises(TypeError):
            Callable()
        with self.assertRaises(TypeError):
            type(Callable)()
        c = Callable[[int], str]
        with self.assertRaises(TypeError):
            c()
        with self.assertRaises(TypeError):
            type(c)()

    def test_callable_wrong_forms(self):
        Callable = self.Callable
        with self.assertRaises(TypeError):
            Callable[int]

    def test_callable_instance_works(self):
        Callable = self.Callable
        def f():
            pass
        self.assertIsInstance(f, Callable)
        self.assertNotIsInstance(None, Callable)

    def test_callable_instance_type_error(self):
        Callable = self.Callable
        def f():
            pass
        with self.assertRaises(TypeError):
            isinstance(f, Callable[[], None])
        with self.assertRaises(TypeError):
            isinstance(f, Callable[[], Any])
        with self.assertRaises(TypeError):
            isinstance(None, Callable[[], None])
        with self.assertRaises(TypeError):
            isinstance(None, Callable[[], Any])

    def test_repr(self):
        Callable = self.Callable
        fullname = f'{Callable.__module__}.Callable'
        ct0 = Callable[[], bool]
        self.assertEqual(repr(ct0), f'{fullname}[[], bool]')
        ct2 = Callable[[str, float], int]
        self.assertEqual(repr(ct2), f'{fullname}[[str, float], int]')
        ctv = Callable[..., str]
        self.assertEqual(repr(ctv), f'{fullname}[..., str]')
        ct3 = Callable[[str, float], list[int]]
        self.assertEqual(repr(ct3), f'{fullname}[[str, float], list[int]]')

    def test_callable_with_ellipsis(self):
        Callable = self.Callable
        def foo(a: Callable[..., T]):
            pass

        self.assertEqual(get_type_hints(foo, globals(), locals()),
                         {'a': Callable[..., T]})

    def test_ellipsis_in_generic(self):
        Callable = self.Callable
        # Shouldn't crash; see https://github.com/python/typing/issues/259
        typing.List[Callable[..., str]]

    def test_or_and_ror(self):
        Callable = self.Callable
        self.assertEqual(Callable | Tuple, Union[Callable, Tuple])
        self.assertEqual(Tuple | Callable, Union[Tuple, Callable])

    def test_basic(self):
        Callable = self.Callable
        alias = Callable[[int, str], float]
        if Callable is collections.abc.Callable:
            self.assertIsInstance(alias, types.GenericAlias)
        self.assertIs(alias.__origin__, collections.abc.Callable)
        self.assertEqual(alias.__args__, (int, str, float))
        self.assertEqual(alias.__parameters__, ())

    def test_weakref(self):
        Callable = self.Callable
        alias = Callable[[int, str], float]
        self.assertEqual(weakref.ref(alias)(), alias)

    def test_pickle(self):
        global T_pickle, P_pickle, TS_pickle  # needed for pickling
        Callable = self.Callable
        T_pickle = TypeVar('T_pickle')
        P_pickle = ParamSpec('P_pickle')
        TS_pickle = TypeVarTuple('TS_pickle')

        samples = [
            Callable[[int, str], float],
            Callable[P_pickle, int],
            Callable[P_pickle, T_pickle],
            Callable[Concatenate[int, P_pickle], int],
            Callable[Concatenate[*TS_pickle, P_pickle], int],
        ]
        for alias in samples:
            for proto in range(pickle.HIGHEST_PROTOCOL + 1):
                with self.subTest(alias=alias, proto=proto):
                    s = pickle.dumps(alias, proto)
                    loaded = pickle.loads(s)
                    self.assertEqual(alias.__origin__, loaded.__origin__)
                    self.assertEqual(alias.__args__, loaded.__args__)
                    self.assertEqual(alias.__parameters__, loaded.__parameters__)

        del T_pickle, P_pickle, TS_pickle  # cleaning up global state

    def test_var_substitution(self):
        Callable = self.Callable
        fullname = f"{Callable.__module__}.Callable"
        C1 = Callable[[int, T], T]
        C2 = Callable[[KT, T], VT]
        C3 = Callable[..., T]
        self.assertEqual(C1[str], Callable[[int, str], str])
        self.assertEqual(C1[None], Callable[[int, type(None)], type(None)])
        self.assertEqual(C2[int, float, str], Callable[[int, float], str])
        self.assertEqual(C3[int], Callable[..., int])
        self.assertEqual(C3[NoReturn], Callable[..., NoReturn])

        # multi chaining
        C4 = C2[int, VT, str]
        self.assertEqual(repr(C4), f"{fullname}[[int, ~VT], str]")
        self.assertEqual(repr(C4[dict]), f"{fullname}[[int, dict], str]")
        self.assertEqual(C4[dict], Callable[[int, dict], str])

        # substitute a nested GenericAlias (both typing and the builtin
        # version)
        C5 = Callable[[typing.List[T], tuple[KT, T], VT], int]
        self.assertEqual(C5[int, str, float],
                         Callable[[typing.List[int], tuple[str, int], float], int])

    def test_type_subst_error(self):
        Callable = self.Callable
        P = ParamSpec('P')
        T = TypeVar('T')

        pat = "Expected a list of types, an ellipsis, ParamSpec, or Concatenate."

        with self.assertRaisesRegex(TypeError, pat):
            Callable[P, T][0, int]

    def test_type_erasure(self):
        Callable = self.Callable
        class C1(Callable):
            def __call__(self):
                return None
        a = C1[[int], T]
        self.assertIs(a().__class__, C1)
        self.assertEqual(a().__orig_class__, C1[[int], T])

    def test_paramspec(self):
        Callable = self.Callable
        fullname = f"{Callable.__module__}.Callable"
        P = ParamSpec('P')
        P2 = ParamSpec('P2')
        C1 = Callable[P, T]
        # substitution
        self.assertEqual(C1[[int], str], Callable[[int], str])
        self.assertEqual(C1[[int, str], str], Callable[[int, str], str])
        self.assertEqual(C1[[], str], Callable[[], str])
        self.assertEqual(C1[..., str], Callable[..., str])
        self.assertEqual(C1[P2, str], Callable[P2, str])
        self.assertEqual(C1[Concatenate[int, P2], str],
                         Callable[Concatenate[int, P2], str])
        self.assertEqual(repr(C1), f"{fullname}[~P, ~T]")
        self.assertEqual(repr(C1[[int, str], str]), f"{fullname}[[int, str], str]")
        with self.assertRaises(TypeError):
            C1[int, str]

        C2 = Callable[P, int]
        self.assertEqual(C2[[int]], Callable[[int], int])
        self.assertEqual(C2[[int, str]], Callable[[int, str], int])
        self.assertEqual(C2[[]], Callable[[], int])
        self.assertEqual(C2[...], Callable[..., int])
        self.assertEqual(C2[P2], Callable[P2, int])
        self.assertEqual(C2[Concatenate[int, P2]],
                         Callable[Concatenate[int, P2], int])
        # special case in PEP 612 where
        # X[int, str, float] == X[[int, str, float]]
        self.assertEqual(C2[int], Callable[[int], int])
        self.assertEqual(C2[int, str], Callable[[int, str], int])
        self.assertEqual(repr(C2), f"{fullname}[~P, int]")
        self.assertEqual(repr(C2[int, str]), f"{fullname}[[int, str], int]")

    def test_concatenate(self):
        Callable = self.Callable
        fullname = f"{Callable.__module__}.Callable"
        T = TypeVar('T')
        P = ParamSpec('P')
        P2 = ParamSpec('P2')
        C = Callable[Concatenate[int, P], T]
        self.assertEqual(repr(C),
                         f"{fullname}[typing.Concatenate[int, ~P], ~T]")
        self.assertEqual(C[P2, int], Callable[Concatenate[int, P2], int])
        self.assertEqual(C[[str, float], int], Callable[[int, str, float], int])
        self.assertEqual(C[[], int], Callable[[int], int])
        self.assertEqual(C[Concatenate[str, P2], int],
                         Callable[Concatenate[int, str, P2], int])
        self.assertEqual(C[..., int], Callable[Concatenate[int, ...], int])

        C = Callable[Concatenate[int, P], int]
        self.assertEqual(repr(C),
                         f"{fullname}[typing.Concatenate[int, ~P], int]")
        self.assertEqual(C[P2], Callable[Concatenate[int, P2], int])
        self.assertEqual(C[[str, float]], Callable[[int, str, float], int])
        self.assertEqual(C[str, float], Callable[[int, str, float], int])
        self.assertEqual(C[[]], Callable[[int], int])
        self.assertEqual(C[Concatenate[str, P2]],
                         Callable[Concatenate[int, str, P2], int])
        self.assertEqual(C[...], Callable[Concatenate[int, ...], int])

    def test_nested_paramspec(self):
        # Since Callable has some special treatment, we want to be sure
        # that substituion works correctly, see gh-103054
        Callable = self.Callable
        P = ParamSpec('P')
        P2 = ParamSpec('P2')
        T = TypeVar('T')
        T2 = TypeVar('T2')
        Ts = TypeVarTuple('Ts')
        class My(Generic[P, T]):
            pass

        self.assertEqual(My.__parameters__, (P, T))

        C1 = My[[int, T2], Callable[P2, T2]]
        self.assertEqual(C1.__args__, ((int, T2), Callable[P2, T2]))
        self.assertEqual(C1.__parameters__, (T2, P2))
        self.assertEqual(C1[str, [list[int], bytes]],
                         My[[int, str], Callable[[list[int], bytes], str]])

        C2 = My[[Callable[[T2], int], list[T2]], str]
        self.assertEqual(C2.__args__, ((Callable[[T2], int], list[T2]), str))
        self.assertEqual(C2.__parameters__, (T2,))
        self.assertEqual(C2[list[str]],
                         My[[Callable[[list[str]], int], list[list[str]]], str])

        C3 = My[[Callable[P2, T2], T2], T2]
        self.assertEqual(C3.__args__, ((Callable[P2, T2], T2), T2))
        self.assertEqual(C3.__parameters__, (P2, T2))
        self.assertEqual(C3[[], int],
                         My[[Callable[[], int], int], int])
        self.assertEqual(C3[[str, bool], int],
                         My[[Callable[[str, bool], int], int], int])
        self.assertEqual(C3[[str, bool], T][int],
                         My[[Callable[[str, bool], int], int], int])

        C4 = My[[Callable[[int, *Ts, str], T2], T2], T2]
        self.assertEqual(C4.__args__, ((Callable[[int, *Ts, str], T2], T2), T2))
        self.assertEqual(C4.__parameters__, (Ts, T2))
        self.assertEqual(C4[bool, bytes, float],
                         My[[Callable[[int, bool, bytes, str], float], float], float])

    def test_errors(self):
        Callable = self.Callable
        alias = Callable[[int, str], float]
        with self.assertRaisesRegex(TypeError, "is not a generic class"):
            alias[int]
        P = ParamSpec('P')
        C1 = Callable[P, T]
        with self.assertRaisesRegex(TypeError, "many arguments for"):
            C1[int, str, str]
        with self.assertRaisesRegex(TypeError, "few arguments for"):
            C1[int]

class TypingCallableTests(BaseCallableTests, BaseTestCase):
    Callable = typing.Callable

    def test_consistency(self):
        # bpo-42195
        # Testing collections.abc.Callable's consistency with typing.Callable
        c1 = typing.Callable[[int, str], dict]
        c2 = collections.abc.Callable[[int, str], dict]
        self.assertEqual(c1.__args__, c2.__args__)
        self.assertEqual(hash(c1.__args__), hash(c2.__args__))


class CollectionsCallableTests(BaseCallableTests, BaseTestCase):
    Callable = collections.abc.Callable


class LiteralTests(BaseTestCase):
    def test_basics(self):
        # All of these are allowed.
        Literal[1]
        Literal[1, 2, 3]
        Literal["x", "y", "z"]
        Literal[None]
        Literal[True]
        Literal[1, "2", False]
        Literal[Literal[1, 2], Literal[4, 5]]
        Literal[b"foo", u"bar"]

    def test_enum(self):
        import enum
        class My(enum.Enum):
            A = 'A'

        self.assertEqual(Literal[My.A].__args__, (My.A,))

    def test_illegal_parameters_do_not_raise_runtime_errors(self):
        # Type checkers should reject these types, but we do not
        # raise errors at runtime to maintain maximum flexibility.
        Literal[int]
        Literal[3j + 2, ..., ()]
        Literal[{"foo": 3, "bar": 4}]
        Literal[T]

    def test_literals_inside_other_types(self):
        List[Literal[1, 2, 3]]
        List[Literal[("foo", "bar", "baz")]]

    def test_repr(self):
        self.assertEqual(repr(Literal[1]), "typing.Literal[1]")
        self.assertEqual(repr(Literal[1, True, "foo"]), "typing.Literal[1, True, 'foo']")
        self.assertEqual(repr(Literal[int]), "typing.Literal[int]")
        self.assertEqual(repr(Literal), "typing.Literal")
        self.assertEqual(repr(Literal[None]), "typing.Literal[None]")
        self.assertEqual(repr(Literal[1, 2, 3, 3]), "typing.Literal[1, 2, 3]")

    def test_dir(self):
        dir_items = set(dir(Literal[1, 2, 3]))
        for required_item in [
            '__args__', '__parameters__', '__origin__',
        ]:
            with self.subTest(required_item=required_item):
                self.assertIn(required_item, dir_items)

    def test_cannot_init(self):
        with self.assertRaises(TypeError):
            Literal()
        with self.assertRaises(TypeError):
            Literal[1]()
        with self.assertRaises(TypeError):
            type(Literal)()
        with self.assertRaises(TypeError):
            type(Literal[1])()

    def test_no_isinstance_or_issubclass(self):
        with self.assertRaises(TypeError):
            isinstance(1, Literal[1])
        with self.assertRaises(TypeError):
            isinstance(int, Literal[1])
        with self.assertRaises(TypeError):
            issubclass(1, Literal[1])
        with self.assertRaises(TypeError):
            issubclass(int, Literal[1])

    def test_no_subclassing(self):
        with self.assertRaises(TypeError):
            class Foo(Literal[1]): pass
        with self.assertRaises(TypeError):
            class Bar(Literal): pass

    def test_no_multiple_subscripts(self):
        with self.assertRaises(TypeError):
            Literal[1][1]

    def test_equal(self):
        self.assertNotEqual(Literal[0], Literal[False])
        self.assertNotEqual(Literal[True], Literal[1])
        self.assertNotEqual(Literal[1], Literal[2])
        self.assertNotEqual(Literal[1, True], Literal[1])
        self.assertNotEqual(Literal[1, True], Literal[1, 1])
        self.assertNotEqual(Literal[1, 2], Literal[True, 2])
        self.assertEqual(Literal[1], Literal[1])
        self.assertEqual(Literal[1, 2], Literal[2, 1])
        self.assertEqual(Literal[1, 2, 3], Literal[1, 2, 3, 3])

    def test_hash(self):
        self.assertEqual(hash(Literal[1]), hash(Literal[1]))
        self.assertEqual(hash(Literal[1, 2]), hash(Literal[2, 1]))
        self.assertEqual(hash(Literal[1, 2, 3]), hash(Literal[1, 2, 3, 3]))

    def test_args(self):
        self.assertEqual(Literal[1, 2, 3].__args__, (1, 2, 3))
        self.assertEqual(Literal[1, 2, 3, 3].__args__, (1, 2, 3))
        self.assertEqual(Literal[1, Literal[2], Literal[3, 4]].__args__, (1, 2, 3, 4))
        # Mutable arguments will not be deduplicated
        self.assertEqual(Literal[[], []].__args__, ([], []))

    def test_flatten(self):
        l1 = Literal[Literal[1], Literal[2], Literal[3]]
        l2 = Literal[Literal[1, 2], 3]
        l3 = Literal[Literal[1, 2, 3]]
        for l in l1, l2, l3:
            self.assertEqual(l, Literal[1, 2, 3])
            self.assertEqual(l.__args__, (1, 2, 3))

    def test_does_not_flatten_enum(self):
        import enum
        class Ints(enum.IntEnum):
            A = 1
            B = 2

        l = Literal[
            Literal[Ints.A],
            Literal[Ints.B],
            Literal[1],
            Literal[2],
        ]
        self.assertEqual(l.__args__, (Ints.A, Ints.B, 1, 2))


XK = TypeVar('XK', str, bytes)
XV = TypeVar('XV')


class SimpleMapping(Generic[XK, XV]):

    def __getitem__(self, key: XK) -> XV:
        ...

    def __setitem__(self, key: XK, value: XV):
        ...

    def get(self, key: XK, default: XV = None) -> XV:
        ...


class MySimpleMapping(SimpleMapping[XK, XV]):

    def __init__(self):
        self.store = {}

    def __getitem__(self, key: str):
        return self.store[key]

    def __setitem__(self, key: str, value):
        self.store[key] = value

    def get(self, key: str, default=None):
        try:
            return self.store[key]
        except KeyError:
            return default


class Coordinate(Protocol):
    x: int
    y: int

@runtime_checkable
class Point(Coordinate, Protocol):
    label: str

class MyPoint:
    x: int
    y: int
    label: str

class XAxis(Protocol):
    x: int

class YAxis(Protocol):
    y: int

@runtime_checkable
class Position(XAxis, YAxis, Protocol):
    pass

@runtime_checkable
class Proto(Protocol):
    attr: int
    def meth(self, arg: str) -> int:
        ...

class Concrete(Proto):
    pass

class Other:
    attr: int = 1
    def meth(self, arg: str) -> int:
        if arg == 'this':
            return 1
        return 0

class NT(NamedTuple):
    x: int
    y: int

@runtime_checkable
class HasCallProtocol(Protocol):
    __call__: typing.Callable


class ProtocolTests(BaseTestCase):
    def test_basic_protocol(self):
        @runtime_checkable
        class P(Protocol):
            def meth(self):
                pass

        class C: pass

        class D:
            def meth(self):
                pass

        def f():
            pass

        self.assertIsSubclass(D, P)
        self.assertIsInstance(D(), P)
        self.assertNotIsSubclass(C, P)
        self.assertNotIsInstance(C(), P)
        self.assertNotIsSubclass(types.FunctionType, P)
        self.assertNotIsInstance(f, P)

    def test_runtime_checkable_generic_non_protocol(self):
        # Make sure this doesn't raise AttributeError
        with self.assertRaisesRegex(
            TypeError,
            "@runtime_checkable can be only applied to protocol classes",
        ):
            @runtime_checkable
            class Foo[T]: ...

    def test_runtime_checkable_generic(self):
        @runtime_checkable
        class Foo[T](Protocol):
            def meth(self) -> T: ...

        class Impl:
            def meth(self) -> int: ...

        self.assertIsSubclass(Impl, Foo)

        class NotImpl:
            def method(self) -> int: ...

        self.assertNotIsSubclass(NotImpl, Foo)

    def test_pep695_generics_can_be_runtime_checkable(self):
        @runtime_checkable
        class HasX(Protocol):
            x: int

        class Bar[T]:
            x: T
            def __init__(self, x):
                self.x = x

        class Capybara[T]:
            y: str
            def __init__(self, y):
                self.y = y

        self.assertIsInstance(Bar(1), HasX)
        self.assertNotIsInstance(Capybara('a'), HasX)

    def test_everything_implements_empty_protocol(self):
        @runtime_checkable
        class Empty(Protocol):
            pass

        class C:
            pass

        def f():
            pass

        for thing in (object, type, tuple, C, types.FunctionType):
            self.assertIsSubclass(thing, Empty)
        for thing in (object(), 1, (), typing, f):
            self.assertIsInstance(thing, Empty)

    def test_function_implements_protocol(self):
        def f():
            pass

        self.assertIsInstance(f, HasCallProtocol)

    def test_no_inheritance_from_nominal(self):
        class C: pass

        class BP(Protocol): pass

        with self.assertRaises(TypeError):
            class P(C, Protocol):
                pass
        with self.assertRaises(TypeError):
            class Q(Protocol, C):
                pass
        with self.assertRaises(TypeError):
            class R(BP, C, Protocol):
                pass

        class D(BP, C): pass

        class E(C, BP): pass

        self.assertNotIsInstance(D(), E)
        self.assertNotIsInstance(E(), D)

    def test_no_instantiation(self):
        class P(Protocol): pass

        with self.assertRaises(TypeError):
            P()

        class C(P): pass

        self.assertIsInstance(C(), C)
        with self.assertRaises(TypeError):
            C(42)

        T = TypeVar('T')

        class PG(Protocol[T]): pass

        with self.assertRaises(TypeError):
            PG()
        with self.assertRaises(TypeError):
            PG[int]()
        with self.assertRaises(TypeError):
            PG[T]()

        class CG(PG[T]): pass

        self.assertIsInstance(CG[int](), CG)
        with self.assertRaises(TypeError):
            CG[int](42)

    def test_protocol_defining_init_does_not_get_overridden(self):
        # check that P.__init__ doesn't get clobbered
        # see https://bugs.python.org/issue44807

        class P(Protocol):
            x: int
            def __init__(self, x: int) -> None:
                self.x = x
        class C: pass

        c = C()
        P.__init__(c, 1)
        self.assertEqual(c.x, 1)

    def test_concrete_class_inheriting_init_from_protocol(self):
        class P(Protocol):
            x: int
            def __init__(self, x: int) -> None:
                self.x = x

        class C(P): pass

        c = C(1)
        self.assertIsInstance(c, C)
        self.assertEqual(c.x, 1)

    def test_cannot_instantiate_abstract(self):
        @runtime_checkable
        class P(Protocol):
            @abc.abstractmethod
            def ameth(self) -> int:
                raise NotImplementedError

        class B(P):
            pass

        class C(B):
            def ameth(self) -> int:
                return 26

        with self.assertRaises(TypeError):
            B()
        self.assertIsInstance(C(), P)

    def test_subprotocols_extending(self):
        class P1(Protocol):
            def meth1(self):
                pass

        @runtime_checkable
        class P2(P1, Protocol):
            def meth2(self):
                pass

        class C:
            def meth1(self):
                pass

            def meth2(self):
                pass

        class C1:
            def meth1(self):
                pass

        class C2:
            def meth2(self):
                pass

        self.assertNotIsInstance(C1(), P2)
        self.assertNotIsInstance(C2(), P2)
        self.assertNotIsSubclass(C1, P2)
        self.assertNotIsSubclass(C2, P2)
        self.assertIsInstance(C(), P2)
        self.assertIsSubclass(C, P2)

    def test_subprotocols_merging(self):
        class P1(Protocol):
            def meth1(self):
                pass

        class P2(Protocol):
            def meth2(self):
                pass

        @runtime_checkable
        class P(P1, P2, Protocol):
            pass

        class C:
            def meth1(self):
                pass

            def meth2(self):
                pass

        class C1:
            def meth1(self):
                pass

        class C2:
            def meth2(self):
                pass

        self.assertNotIsInstance(C1(), P)
        self.assertNotIsInstance(C2(), P)
        self.assertNotIsSubclass(C1, P)
        self.assertNotIsSubclass(C2, P)
        self.assertIsInstance(C(), P)
        self.assertIsSubclass(C, P)

    def test_protocols_issubclass(self):
        T = TypeVar('T')

        @runtime_checkable
        class P(Protocol):
            def x(self): ...

        @runtime_checkable
        class PG(Protocol[T]):
            def x(self): ...

        class BadP(Protocol):
            def x(self): ...

        class BadPG(Protocol[T]):
            def x(self): ...

        class C:
            def x(self): ...

        self.assertIsSubclass(C, P)
        self.assertIsSubclass(C, PG)
        self.assertIsSubclass(BadP, PG)

        no_subscripted_generics = (
            "Subscripted generics cannot be used with class and instance checks"
        )

        with self.assertRaisesRegex(TypeError, no_subscripted_generics):
            issubclass(C, PG[T])
        with self.assertRaisesRegex(TypeError, no_subscripted_generics):
            issubclass(C, PG[C])

        only_runtime_checkable_protocols = (
            "Instance and class checks can only be used with "
            "@runtime_checkable protocols"
        )

        with self.assertRaisesRegex(TypeError, only_runtime_checkable_protocols):
            issubclass(C, BadP)
        with self.assertRaisesRegex(TypeError, only_runtime_checkable_protocols):
            issubclass(C, BadPG)

        with self.assertRaisesRegex(TypeError, no_subscripted_generics):
            issubclass(P, PG[T])
        with self.assertRaisesRegex(TypeError, no_subscripted_generics):
            issubclass(PG, PG[int])

        only_classes_allowed = r"issubclass\(\) arg 1 must be a class"

        with self.assertRaisesRegex(TypeError, only_classes_allowed):
            issubclass(1, P)
        with self.assertRaisesRegex(TypeError, only_classes_allowed):
            issubclass(1, PG)
        with self.assertRaisesRegex(TypeError, only_classes_allowed):
            issubclass(1, BadP)
        with self.assertRaisesRegex(TypeError, only_classes_allowed):
            issubclass(1, BadPG)

    def test_implicit_issubclass_between_two_protocols(self):
        @runtime_checkable
        class CallableMembersProto(Protocol):
            def meth(self): ...

        # All the below protocols should be considered "subclasses"
        # of CallableMembersProto at runtime,
        # even though none of them explicitly subclass CallableMembersProto

        class IdenticalProto(Protocol):
            def meth(self): ...

        class SupersetProto(Protocol):
            def meth(self): ...
            def meth2(self): ...

        class NonCallableMembersProto(Protocol):
            meth: Callable[[], None]

        class NonCallableMembersSupersetProto(Protocol):
            meth: Callable[[], None]
            meth2: Callable[[str, int], bool]

        class MixedMembersProto1(Protocol):
            meth: Callable[[], None]
            def meth2(self): ...

        class MixedMembersProto2(Protocol):
            def meth(self): ...
            meth2: Callable[[str, int], bool]

        for proto in (
            IdenticalProto, SupersetProto, NonCallableMembersProto,
            NonCallableMembersSupersetProto, MixedMembersProto1, MixedMembersProto2
        ):
            with self.subTest(proto=proto.__name__):
                self.assertIsSubclass(proto, CallableMembersProto)

        # These two shouldn't be considered subclasses of CallableMembersProto, however,
        # since they don't have the `meth` protocol member

        class EmptyProtocol(Protocol): ...
        class UnrelatedProtocol(Protocol):
            def wut(self): ...

        self.assertNotIsSubclass(EmptyProtocol, CallableMembersProto)
        self.assertNotIsSubclass(UnrelatedProtocol, CallableMembersProto)

        # These aren't protocols at all (despite having annotations),
        # so they should only be considered subclasses of CallableMembersProto
        # if they *actually have an attribute* matching the `meth` member
        # (just having an annotation is insufficient)

        class AnnotatedButNotAProtocol:
            meth: Callable[[], None]

        class NotAProtocolButAnImplicitSubclass:
            def meth(self): pass

        class NotAProtocolButAnImplicitSubclass2:
            meth: Callable[[], None]
            def meth(self): pass

        class NotAProtocolButAnImplicitSubclass3:
            meth: Callable[[], None]
            meth2: Callable[[int, str], bool]
            def meth(self): pass
            def meth2(self, x, y): return True

        self.assertNotIsSubclass(AnnotatedButNotAProtocol, CallableMembersProto)
        self.assertIsSubclass(NotAProtocolButAnImplicitSubclass, CallableMembersProto)
        self.assertIsSubclass(NotAProtocolButAnImplicitSubclass2, CallableMembersProto)
        self.assertIsSubclass(NotAProtocolButAnImplicitSubclass3, CallableMembersProto)

    def test_isinstance_checks_not_at_whim_of_gc(self):
        self.addCleanup(gc.enable)
        gc.disable()

        with self.assertRaisesRegex(
            TypeError,
            "Protocols can only inherit from other protocols"
        ):
            class Foo(collections.abc.Mapping, Protocol):
                pass

        self.assertNotIsInstance([], collections.abc.Mapping)

    def test_issubclass_and_isinstance_on_Protocol_itself(self):
        class C:
            def x(self): pass

        self.assertNotIsSubclass(object, Protocol)
        self.assertNotIsInstance(object(), Protocol)

        self.assertNotIsSubclass(str, Protocol)
        self.assertNotIsInstance('foo', Protocol)

        self.assertNotIsSubclass(C, Protocol)
        self.assertNotIsInstance(C(), Protocol)

        only_classes_allowed = r"issubclass\(\) arg 1 must be a class"

        with self.assertRaisesRegex(TypeError, only_classes_allowed):
            issubclass(1, Protocol)
        with self.assertRaisesRegex(TypeError, only_classes_allowed):
            issubclass('foo', Protocol)
        with self.assertRaisesRegex(TypeError, only_classes_allowed):
            issubclass(C(), Protocol)

        T = TypeVar('T')

        @runtime_checkable
        class EmptyProtocol(Protocol): pass

        @runtime_checkable
        class SupportsStartsWith(Protocol):
            def startswith(self, x: str) -> bool: ...

        @runtime_checkable
        class SupportsX(Protocol[T]):
            def x(self): ...

        for proto in EmptyProtocol, SupportsStartsWith, SupportsX:
            with self.subTest(proto=proto.__name__):
                self.assertIsSubclass(proto, Protocol)

        # gh-105237 / PR #105239:
        # check that the presence of Protocol subclasses
        # where `issubclass(X, <subclass>)` evaluates to True
        # doesn't influence the result of `issubclass(X, Protocol)`

        self.assertIsSubclass(object, EmptyProtocol)
        self.assertIsInstance(object(), EmptyProtocol)
        self.assertNotIsSubclass(object, Protocol)
        self.assertNotIsInstance(object(), Protocol)

        self.assertIsSubclass(str, SupportsStartsWith)
        self.assertIsInstance('foo', SupportsStartsWith)
        self.assertNotIsSubclass(str, Protocol)
        self.assertNotIsInstance('foo', Protocol)

        self.assertIsSubclass(C, SupportsX)
        self.assertIsInstance(C(), SupportsX)
        self.assertNotIsSubclass(C, Protocol)
        self.assertNotIsInstance(C(), Protocol)

    def test_protocols_issubclass_non_callable(self):
        class C:
            x = 1

        @runtime_checkable
        class PNonCall(Protocol):
            x = 1

        non_callable_members_illegal = (
            "Protocols with non-method members don't support issubclass()"
        )

        with self.assertRaisesRegex(TypeError, non_callable_members_illegal):
            issubclass(C, PNonCall)

        self.assertIsInstance(C(), PNonCall)
        PNonCall.register(C)

        with self.assertRaisesRegex(TypeError, non_callable_members_illegal):
            issubclass(C, PNonCall)

        self.assertIsInstance(C(), PNonCall)

        # check that non-protocol subclasses are not affected
        class D(PNonCall): ...

        self.assertNotIsSubclass(C, D)
        self.assertNotIsInstance(C(), D)
        D.register(C)
        self.assertIsSubclass(C, D)
        self.assertIsInstance(C(), D)

        with self.assertRaisesRegex(TypeError, non_callable_members_illegal):
            issubclass(D, PNonCall)

    def test_no_weird_caching_with_issubclass_after_isinstance(self):
        @runtime_checkable
        class Spam(Protocol):
            x: int

        class Eggs:
            def __init__(self) -> None:
                self.x = 42

        self.assertIsInstance(Eggs(), Spam)

        # gh-104555: If we didn't override ABCMeta.__subclasscheck__ in _ProtocolMeta,
        # TypeError wouldn't be raised here,
        # as the cached result of the isinstance() check immediately above
        # would mean the issubclass() call would short-circuit
        # before we got to the "raise TypeError" line
        with self.assertRaisesRegex(
            TypeError,
            "Protocols with non-method members don't support issubclass()"
        ):
            issubclass(Eggs, Spam)

    def test_no_weird_caching_with_issubclass_after_isinstance_2(self):
        @runtime_checkable
        class Spam(Protocol):
            x: int

        class Eggs: ...

        self.assertNotIsInstance(Eggs(), Spam)

        # gh-104555: If we didn't override ABCMeta.__subclasscheck__ in _ProtocolMeta,
        # TypeError wouldn't be raised here,
        # as the cached result of the isinstance() check immediately above
        # would mean the issubclass() call would short-circuit
        # before we got to the "raise TypeError" line
        with self.assertRaisesRegex(
            TypeError,
            "Protocols with non-method members don't support issubclass()"
        ):
            issubclass(Eggs, Spam)

    def test_no_weird_caching_with_issubclass_after_isinstance_3(self):
        @runtime_checkable
        class Spam(Protocol):
            x: int

        class Eggs:
            def __getattr__(self, attr):
                if attr == "x":
                    return 42
                raise AttributeError(attr)

        self.assertNotIsInstance(Eggs(), Spam)

        # gh-104555: If we didn't override ABCMeta.__subclasscheck__ in _ProtocolMeta,
        # TypeError wouldn't be raised here,
        # as the cached result of the isinstance() check immediately above
        # would mean the issubclass() call would short-circuit
        # before we got to the "raise TypeError" line
        with self.assertRaisesRegex(
            TypeError,
            "Protocols with non-method members don't support issubclass()"
        ):
            issubclass(Eggs, Spam)

    def test_no_weird_caching_with_issubclass_after_isinstance_pep695(self):
        @runtime_checkable
        class Spam[T](Protocol):
            x: T

        class Eggs[T]:
            def __init__(self, x: T) -> None:
                self.x = x

        self.assertIsInstance(Eggs(42), Spam)

        # gh-104555: If we didn't override ABCMeta.__subclasscheck__ in _ProtocolMeta,
        # TypeError wouldn't be raised here,
        # as the cached result of the isinstance() check immediately above
        # would mean the issubclass() call would short-circuit
        # before we got to the "raise TypeError" line
        with self.assertRaisesRegex(
            TypeError,
            "Protocols with non-method members don't support issubclass()"
        ):
            issubclass(Eggs, Spam)

    def test_protocols_isinstance(self):
        T = TypeVar('T')

        @runtime_checkable
        class P(Protocol):
            def meth(x): ...

        @runtime_checkable
        class PG(Protocol[T]):
            def meth(x): ...

        @runtime_checkable
        class WeirdProto(Protocol):
            meth = str.maketrans

        @runtime_checkable
        class WeirdProto2(Protocol):
            meth = lambda *args, **kwargs: None

        class CustomCallable:
            def __call__(self, *args, **kwargs):
                pass

        @runtime_checkable
        class WeirderProto(Protocol):
            meth = CustomCallable()

        class BadP(Protocol):
            def meth(x): ...

        class BadPG(Protocol[T]):
            def meth(x): ...

        class C:
            def meth(x): ...

        class C2:
            def __init__(self):
                self.meth = lambda: None

        for klass in C, C2:
            for proto in P, PG, WeirdProto, WeirdProto2, WeirderProto:
                with self.subTest(klass=klass.__name__, proto=proto.__name__):
                    self.assertIsInstance(klass(), proto)

        no_subscripted_generics = "Subscripted generics cannot be used with class and instance checks"

        with self.assertRaisesRegex(TypeError, no_subscripted_generics):
            isinstance(C(), PG[T])
        with self.assertRaisesRegex(TypeError, no_subscripted_generics):
            isinstance(C(), PG[C])

        only_runtime_checkable_msg = (
            "Instance and class checks can only be used "
            "with @runtime_checkable protocols"
        )

        with self.assertRaisesRegex(TypeError, only_runtime_checkable_msg):
            isinstance(C(), BadP)
        with self.assertRaisesRegex(TypeError, only_runtime_checkable_msg):
            isinstance(C(), BadPG)

    def test_protocols_isinstance_properties_and_descriptors(self):
        class C:
            @property
            def attr(self):
                return 42

        class CustomDescriptor:
            def __get__(self, obj, objtype=None):
                return 42

        class D:
            attr = CustomDescriptor()

        # Check that properties set on superclasses
        # are still found by the isinstance() logic
        class E(C): ...
        class F(D): ...

        class Empty: ...

        T = TypeVar('T')

        @runtime_checkable
        class P(Protocol):
            @property
            def attr(self): ...

        @runtime_checkable
        class P1(Protocol):
            attr: int

        @runtime_checkable
        class PG(Protocol[T]):
            @property
            def attr(self): ...

        @runtime_checkable
        class PG1(Protocol[T]):
            attr: T

        @runtime_checkable
        class MethodP(Protocol):
            def attr(self): ...

        @runtime_checkable
        class MethodPG(Protocol[T]):
            def attr(self) -> T: ...

        for protocol_class in P, P1, PG, PG1, MethodP, MethodPG:
            for klass in C, D, E, F:
                with self.subTest(
                    klass=klass.__name__,
                    protocol_class=protocol_class.__name__
                ):
                    self.assertIsInstance(klass(), protocol_class)

            with self.subTest(klass="Empty", protocol_class=protocol_class.__name__):
                self.assertNotIsInstance(Empty(), protocol_class)

        class BadP(Protocol):
            @property
            def attr(self): ...

        class BadP1(Protocol):
            attr: int

        class BadPG(Protocol[T]):
            @property
            def attr(self): ...

        class BadPG1(Protocol[T]):
            attr: T

        cases = (
            PG[T], PG[C], PG1[T], PG1[C], MethodPG[T],
            MethodPG[C], BadP, BadP1, BadPG, BadPG1
        )

        for obj in cases:
            for klass in C, D, E, F, Empty:
                with self.subTest(klass=klass.__name__, obj=obj):
                    with self.assertRaises(TypeError):
                        isinstance(klass(), obj)

    def test_protocols_isinstance_not_fooled_by_custom_dir(self):
        @runtime_checkable
        class HasX(Protocol):
            x: int

        class CustomDirWithX:
            x = 10
            def __dir__(self):
                return []

        class CustomDirWithoutX:
            def __dir__(self):
                return ["x"]

        self.assertIsInstance(CustomDirWithX(), HasX)
        self.assertNotIsInstance(CustomDirWithoutX(), HasX)

    def test_protocols_isinstance_attribute_access_with_side_effects(self):
        class C:
            @property
            def attr(self):
                raise AttributeError('no')

        class CustomDescriptor:
            def __get__(self, obj, objtype=None):
                raise RuntimeError("NO")

        class D:
            attr = CustomDescriptor()

        # Check that properties set on superclasses
        # are still found by the isinstance() logic
        class E(C): ...
        class F(D): ...

        class WhyWouldYouDoThis:
            def __getattr__(self, name):
                raise RuntimeError("wut")

        T = TypeVar('T')

        @runtime_checkable
        class P(Protocol):
            @property
            def attr(self): ...

        @runtime_checkable
        class P1(Protocol):
            attr: int

        @runtime_checkable
        class PG(Protocol[T]):
            @property
            def attr(self): ...

        @runtime_checkable
        class PG1(Protocol[T]):
            attr: T

        @runtime_checkable
        class MethodP(Protocol):
            def attr(self): ...

        @runtime_checkable
        class MethodPG(Protocol[T]):
            def attr(self) -> T: ...

        for protocol_class in P, P1, PG, PG1, MethodP, MethodPG:
            for klass in C, D, E, F:
                with self.subTest(
                    klass=klass.__name__,
                    protocol_class=protocol_class.__name__
                ):
                    self.assertIsInstance(klass(), protocol_class)

            with self.subTest(
                klass="WhyWouldYouDoThis",
                protocol_class=protocol_class.__name__
            ):
                self.assertNotIsInstance(WhyWouldYouDoThis(), protocol_class)

    def test_protocols_isinstance___slots__(self):
        # As per the consensus in https://github.com/python/typing/issues/1367,
        # this is desirable behaviour
        @runtime_checkable
        class HasX(Protocol):
            x: int

        class HasNothingButSlots:
            __slots__ = ("x",)

        self.assertIsInstance(HasNothingButSlots(), HasX)

    def test_protocols_isinstance_py36(self):
        class APoint:
            def __init__(self, x, y, label):
                self.x = x
                self.y = y
                self.label = label

        class BPoint:
            label = 'B'

            def __init__(self, x, y):
                self.x = x
                self.y = y

        class C:
            def __init__(self, attr):
                self.attr = attr

            def meth(self, arg):
                return 0

        class Bad: pass

        self.assertIsInstance(APoint(1, 2, 'A'), Point)
        self.assertIsInstance(BPoint(1, 2), Point)
        self.assertNotIsInstance(MyPoint(), Point)
        self.assertIsInstance(BPoint(1, 2), Position)
        self.assertIsInstance(Other(), Proto)
        self.assertIsInstance(Concrete(), Proto)
        self.assertIsInstance(C(42), Proto)
        self.assertNotIsInstance(Bad(), Proto)
        self.assertNotIsInstance(Bad(), Point)
        self.assertNotIsInstance(Bad(), Position)
        self.assertNotIsInstance(Bad(), Concrete)
        self.assertNotIsInstance(Other(), Concrete)
        self.assertIsInstance(NT(1, 2), Position)

    def test_protocols_isinstance_init(self):
        T = TypeVar('T')

        @runtime_checkable
        class P(Protocol):
            x = 1

        @runtime_checkable
        class PG(Protocol[T]):
            x = 1

        class C:
            def __init__(self, x):
                self.x = x

        self.assertIsInstance(C(1), P)
        self.assertIsInstance(C(1), PG)

    def test_protocols_isinstance_monkeypatching(self):
        @runtime_checkable
        class HasX(Protocol):
            x: int

        class Foo: ...

        f = Foo()
        self.assertNotIsInstance(f, HasX)
        f.x = 42
        self.assertIsInstance(f, HasX)
        del f.x
        self.assertNotIsInstance(f, HasX)

    def test_protocol_checks_after_subscript(self):
        class P(Protocol[T]): pass
        class C(P[T]): pass
        class Other1: pass
        class Other2: pass
        CA = C[Any]

        self.assertNotIsInstance(Other1(), C)
        self.assertNotIsSubclass(Other2, C)

        class D1(C[Any]): pass
        class D2(C[Any]): pass
        CI = C[int]

        self.assertIsInstance(D1(), C)
        self.assertIsSubclass(D2, C)

    def test_protocols_support_register(self):
        @runtime_checkable
        class P(Protocol):
            x = 1

        class PM(Protocol):
            def meth(self): pass

        class D(PM): pass

        class C: pass

        D.register(C)
        P.register(C)
        self.assertIsInstance(C(), P)
        self.assertIsInstance(C(), D)

    def test_none_on_non_callable_doesnt_block_implementation(self):
        @runtime_checkable
        class P(Protocol):
            x = 1

        class A:
            x = 1

        class B(A):
            x = None

        class C:
            def __init__(self):
                self.x = None

        self.assertIsInstance(B(), P)
        self.assertIsInstance(C(), P)

    def test_none_on_callable_blocks_implementation(self):
        @runtime_checkable
        class P(Protocol):
            def x(self): ...

        class A:
            def x(self): ...

        class B(A):
            x = None

        class C:
            def __init__(self):
                self.x = None

        self.assertNotIsInstance(B(), P)
        self.assertNotIsInstance(C(), P)

    def test_non_protocol_subclasses(self):
        class P(Protocol):
            x = 1

        @runtime_checkable
        class PR(Protocol):
            def meth(self): pass

        class NonP(P):
            x = 1

        class NonPR(PR): pass

        class C(metaclass=abc.ABCMeta):
            x = 1

        class D(metaclass=abc.ABCMeta):
            def meth(self): pass

        self.assertNotIsInstance(C(), NonP)
        self.assertNotIsInstance(D(), NonPR)
        self.assertNotIsSubclass(C, NonP)
        self.assertNotIsSubclass(D, NonPR)
        self.assertIsInstance(NonPR(), PR)
        self.assertIsSubclass(NonPR, PR)

        self.assertNotIn("__protocol_attrs__", vars(NonP))
        self.assertNotIn("__protocol_attrs__", vars(NonPR))
        self.assertNotIn("__non_callable_proto_members__", vars(NonP))
        self.assertNotIn("__non_callable_proto_members__", vars(NonPR))

        self.assertEqual(get_protocol_members(P), {"x"})
        self.assertEqual(get_protocol_members(PR), {"meth"})

        # the returned object should be immutable,
        # and should be a different object to the original attribute
        # to prevent users from (accidentally or deliberately)
        # mutating the attribute on the original class
        self.assertIsInstance(get_protocol_members(P), frozenset)
        self.assertIsNot(get_protocol_members(P), P.__protocol_attrs__)
        self.assertIsInstance(get_protocol_members(PR), frozenset)
        self.assertIsNot(get_protocol_members(PR), P.__protocol_attrs__)

        acceptable_extra_attrs = {
            '_is_protocol', '_is_runtime_protocol', '__parameters__',
            '__init__', '__annotations__', '__subclasshook__', '__annotate__',
        }
        self.assertLessEqual(vars(NonP).keys(), vars(C).keys() | acceptable_extra_attrs)
        self.assertLessEqual(
            vars(NonPR).keys(), vars(D).keys() | acceptable_extra_attrs
        )

    def test_custom_subclasshook(self):
        class P(Protocol):
            x = 1

        class OKClass: pass

        class BadClass:
            x = 1

        class C(P):
            @classmethod
            def __subclasshook__(cls, other):
                return other.__name__.startswith("OK")

        self.assertIsInstance(OKClass(), C)
        self.assertNotIsInstance(BadClass(), C)
        self.assertIsSubclass(OKClass, C)
        self.assertNotIsSubclass(BadClass, C)

    def test_custom_subclasshook_2(self):
        @runtime_checkable
        class HasX(Protocol):
            # The presence of a non-callable member
            # would mean issubclass() checks would fail with TypeError
            # if it weren't for the custom `__subclasshook__` method
            x = 1

            @classmethod
            def __subclasshook__(cls, other):
                return hasattr(other, 'x')

        class Empty: pass

        class ImplementsHasX:
            x = 1

        self.assertIsInstance(ImplementsHasX(), HasX)
        self.assertNotIsInstance(Empty(), HasX)
        self.assertIsSubclass(ImplementsHasX, HasX)
        self.assertNotIsSubclass(Empty, HasX)

        # isinstance() and issubclass() checks against this still raise TypeError,
        # despite the presence of the custom __subclasshook__ method,
        # as it's not decorated with @runtime_checkable
        class NotRuntimeCheckable(Protocol):
            @classmethod
            def __subclasshook__(cls, other):
                return hasattr(other, 'x')

        must_be_runtime_checkable = (
            "Instance and class checks can only be used "
            "with @runtime_checkable protocols"
        )

        with self.assertRaisesRegex(TypeError, must_be_runtime_checkable):
            issubclass(object, NotRuntimeCheckable)
        with self.assertRaisesRegex(TypeError, must_be_runtime_checkable):
            isinstance(object(), NotRuntimeCheckable)

    def test_issubclass_fails_correctly(self):
        @runtime_checkable
        class NonCallableMembers(Protocol):
            x = 1

        class NotRuntimeCheckable(Protocol):
            def callable_member(self) -> int: ...

        @runtime_checkable
        class RuntimeCheckable(Protocol):
            def callable_member(self) -> int: ...

        class C: pass

        # These three all exercise different code paths,
        # but should result in the same error message:
        for protocol in NonCallableMembers, NotRuntimeCheckable, RuntimeCheckable:
            with self.subTest(proto_name=protocol.__name__):
                with self.assertRaisesRegex(
                    TypeError, r"issubclass\(\) arg 1 must be a class"
                ):
                    issubclass(C(), protocol)

    def test_defining_generic_protocols(self):
        T = TypeVar('T')
        S = TypeVar('S')

        @runtime_checkable
        class PR(Protocol[T, S]):
            def meth(self): pass

        class P(PR[int, T], Protocol[T]):
            y = 1

        with self.assertRaises(TypeError):
            PR[int]
        with self.assertRaises(TypeError):
            P[int, str]

        class C(PR[int, T]): pass

        self.assertIsInstance(C[str](), C)

    def test_defining_generic_protocols_old_style(self):
        T = TypeVar('T')
        S = TypeVar('S')

        @runtime_checkable
        class PR(Protocol, Generic[T, S]):
            def meth(self): pass

        class P(PR[int, str], Protocol):
            y = 1

        with self.assertRaises(TypeError):
            issubclass(PR[int, str], PR)
        self.assertIsSubclass(P, PR)
        with self.assertRaises(TypeError):
            PR[int]

        class P1(Protocol, Generic[T]):
            def bar(self, x: T) -> str: ...

        class P2(Generic[T], Protocol):
            def bar(self, x: T) -> str: ...

        @runtime_checkable
        class PSub(P1[str], Protocol):
            x = 1

        class Test:
            x = 1

            def bar(self, x: str) -> str:
                return x

        self.assertIsInstance(Test(), PSub)

    def test_pep695_generic_protocol_callable_members(self):
        @runtime_checkable
        class Foo[T](Protocol):
            def meth(self, x: T) -> None: ...

        class Bar[T]:
            def meth(self, x: T) -> None: ...

        self.assertIsInstance(Bar(), Foo)
        self.assertIsSubclass(Bar, Foo)

        @runtime_checkable
        class SupportsTrunc[T](Protocol):
            def __trunc__(self) -> T: ...

        self.assertIsInstance(0.0, SupportsTrunc)
        self.assertIsSubclass(float, SupportsTrunc)

    def test_init_called(self):
        T = TypeVar('T')

        class P(Protocol[T]): pass

        class C(P[T]):
            def __init__(self):
                self.test = 'OK'

        self.assertEqual(C[int]().test, 'OK')

        class B:
            def __init__(self):
                self.test = 'OK'

        class D1(B, P[T]):
            pass

        self.assertEqual(D1[int]().test, 'OK')

        class D2(P[T], B):
            pass

        self.assertEqual(D2[int]().test, 'OK')

    def test_new_called(self):
        T = TypeVar('T')

        class P(Protocol[T]): pass

        class C(P[T]):
            def __new__(cls, *args):
                self = super().__new__(cls, *args)
                self.test = 'OK'
                return self

        self.assertEqual(C[int]().test, 'OK')
        with self.assertRaises(TypeError):
            C[int](42)
        with self.assertRaises(TypeError):
            C[int](a=42)

    def test_protocols_bad_subscripts(self):
        T = TypeVar('T')
        S = TypeVar('S')
        with self.assertRaises(TypeError):
            class P(Protocol[T, T]): pass
        with self.assertRaises(TypeError):
            class Q(Protocol[int]): pass
        with self.assertRaises(TypeError):
            class R(Protocol[T], Protocol[S]): pass
        with self.assertRaises(TypeError):
            class S(typing.Mapping[T, S], Protocol[T]): pass

    def test_generic_protocols_repr(self):
        T = TypeVar('T')
        S = TypeVar('S')

        class P(Protocol[T, S]): pass

        self.assertTrue(repr(P[T, S]).endswith('P[~T, ~S]'))
        self.assertTrue(repr(P[int, str]).endswith('P[int, str]'))

    def test_generic_protocols_eq(self):
        T = TypeVar('T')
        S = TypeVar('S')

        class P(Protocol[T, S]): pass

        self.assertEqual(P, P)
        self.assertEqual(P[int, T], P[int, T])
        self.assertEqual(P[T, T][Tuple[T, S]][int, str],
                         P[Tuple[int, str], Tuple[int, str]])

    def test_generic_protocols_special_from_generic(self):
        T = TypeVar('T')

        class P(Protocol[T]): pass

        self.assertEqual(P.__parameters__, (T,))
        self.assertEqual(P[int].__parameters__, ())
        self.assertEqual(P[int].__args__, (int,))
        self.assertIs(P[int].__origin__, P)

    def test_generic_protocols_special_from_protocol(self):
        @runtime_checkable
        class PR(Protocol):
            x = 1

        class P(Protocol):
            def meth(self):
                pass

        T = TypeVar('T')

        class PG(Protocol[T]):
            x = 1

            def meth(self):
                pass

        self.assertTrue(P._is_protocol)
        self.assertTrue(PR._is_protocol)
        self.assertTrue(PG._is_protocol)
        self.assertFalse(P._is_runtime_protocol)
        self.assertTrue(PR._is_runtime_protocol)
        self.assertTrue(PG[int]._is_protocol)
        self.assertEqual(typing._get_protocol_attrs(P), {'meth'})
        self.assertEqual(typing._get_protocol_attrs(PR), {'x'})
        self.assertEqual(frozenset(typing._get_protocol_attrs(PG)),
                         frozenset({'x', 'meth'}))

    def test_no_runtime_deco_on_nominal(self):
        with self.assertRaises(TypeError):
            @runtime_checkable
            class C: pass

        class Proto(Protocol):
            x = 1

        with self.assertRaises(TypeError):
            @runtime_checkable
            class Concrete(Proto):
                pass

    def test_none_treated_correctly(self):
        @runtime_checkable
        class P(Protocol):
            x = None  # type: int

        class B(object): pass

        self.assertNotIsInstance(B(), P)

        class C:
            x = 1

        class D:
            x = None

        self.assertIsInstance(C(), P)
        self.assertIsInstance(D(), P)

        class CI:
            def __init__(self):
                self.x = 1

        class DI:
            def __init__(self):
                self.x = None

        self.assertIsInstance(CI(), P)
        self.assertIsInstance(DI(), P)

    def test_protocols_in_unions(self):
        class P(Protocol):
            x = None  # type: int

        Alias = typing.Union[typing.Iterable, P]
        Alias2 = typing.Union[P, typing.Iterable]
        self.assertEqual(Alias, Alias2)

    def test_protocols_pickleable(self):
        global P, CP  # pickle wants to reference the class by name
        T = TypeVar('T')

        @runtime_checkable
        class P(Protocol[T]):
            x = 1

        class CP(P[int]):
            pass

        c = CP()
        c.foo = 42
        c.bar = 'abc'
        for proto in range(pickle.HIGHEST_PROTOCOL + 1):
            z = pickle.dumps(c, proto)
            x = pickle.loads(z)
            self.assertEqual(x.foo, 42)
            self.assertEqual(x.bar, 'abc')
            self.assertEqual(x.x, 1)
            self.assertEqual(x.__dict__, {'foo': 42, 'bar': 'abc'})
            s = pickle.dumps(P, proto)
            D = pickle.loads(s)

            class E:
                x = 1

            self.assertIsInstance(E(), D)

    def test_runtime_checkable_with_match_args(self):
        @runtime_checkable
        class P_regular(Protocol):
            x: int
            y: int

        @runtime_checkable
        class P_match(Protocol):
            __match_args__ = ('x', 'y')
            x: int
            y: int

        class Regular:
            def __init__(self, x: int, y: int):
                self.x = x
                self.y = y

        class WithMatch:
            __match_args__ = ('x', 'y', 'z')
            def __init__(self, x: int, y: int, z: int):
                self.x = x
                self.y = y
                self.z = z

        class Nope: ...

        self.assertIsInstance(Regular(1, 2), P_regular)
        self.assertIsInstance(Regular(1, 2), P_match)
        self.assertIsInstance(WithMatch(1, 2, 3), P_regular)
        self.assertIsInstance(WithMatch(1, 2, 3), P_match)
        self.assertNotIsInstance(Nope(), P_regular)
        self.assertNotIsInstance(Nope(), P_match)

    def test_supports_int(self):
        self.assertIsSubclass(int, typing.SupportsInt)
        self.assertNotIsSubclass(str, typing.SupportsInt)

    def test_supports_float(self):
        self.assertIsSubclass(float, typing.SupportsFloat)
        self.assertNotIsSubclass(str, typing.SupportsFloat)

    def test_supports_complex(self):

        class C:
            def __complex__(self):
                return 0j

        self.assertIsSubclass(complex, typing.SupportsComplex)
        self.assertIsSubclass(C, typing.SupportsComplex)
        self.assertNotIsSubclass(str, typing.SupportsComplex)

    def test_supports_bytes(self):

        class B:
            def __bytes__(self):
                return b''

        self.assertIsSubclass(bytes, typing.SupportsBytes)
        self.assertIsSubclass(B, typing.SupportsBytes)
        self.assertNotIsSubclass(str, typing.SupportsBytes)

    def test_supports_abs(self):
        self.assertIsSubclass(float, typing.SupportsAbs)
        self.assertIsSubclass(int, typing.SupportsAbs)
        self.assertNotIsSubclass(str, typing.SupportsAbs)

    def test_supports_round(self):
        issubclass(float, typing.SupportsRound)
        self.assertIsSubclass(float, typing.SupportsRound)
        self.assertIsSubclass(int, typing.SupportsRound)
        self.assertNotIsSubclass(str, typing.SupportsRound)

    def test_reversible(self):
        self.assertIsSubclass(list, typing.Reversible)
        self.assertNotIsSubclass(int, typing.Reversible)

    def test_supports_index(self):
        self.assertIsSubclass(int, typing.SupportsIndex)
        self.assertNotIsSubclass(str, typing.SupportsIndex)

    def test_bundled_protocol_instance_works(self):
        self.assertIsInstance(0, typing.SupportsAbs)
        class C1(typing.SupportsInt):
            def __int__(self) -> int:
                return 42
        class C2(C1):
            pass
        c = C2()
        self.assertIsInstance(c, C1)

    def test_collections_protocols_allowed(self):
        @runtime_checkable
        class Custom(collections.abc.Iterable, Protocol):
            def close(self): ...

        class A: pass
        class B:
            def __iter__(self):
                return []
            def close(self):
                return 0

        self.assertIsSubclass(B, Custom)
        self.assertNotIsSubclass(A, Custom)

        @runtime_checkable
        class ReleasableBuffer(collections.abc.Buffer, Protocol):
            def __release_buffer__(self, mv: memoryview) -> None: ...

        class C: pass
        class D:
            def __buffer__(self, flags: int) -> memoryview:
                return memoryview(b'')
            def __release_buffer__(self, mv: memoryview) -> None:
                pass

        self.assertIsSubclass(D, ReleasableBuffer)
        self.assertIsInstance(D(), ReleasableBuffer)
        self.assertNotIsSubclass(C, ReleasableBuffer)
        self.assertNotIsInstance(C(), ReleasableBuffer)

    def test_builtin_protocol_allowlist(self):
        with self.assertRaises(TypeError):
            class CustomProtocol(TestCase, Protocol):
                pass

        class CustomContextManager(typing.ContextManager, Protocol):
            pass

    def test_non_runtime_protocol_isinstance_check(self):
        class P(Protocol):
            x: int

        with self.assertRaisesRegex(TypeError, "@runtime_checkable"):
            isinstance(1, P)

    def test_super_call_init(self):
        class P(Protocol):
            x: int

        class Foo(P):
            def __init__(self):
                super().__init__()

        Foo()  # Previously triggered RecursionError

    def test_get_protocol_members(self):
        with self.assertRaisesRegex(TypeError, "not a Protocol"):
            get_protocol_members(object)
        with self.assertRaisesRegex(TypeError, "not a Protocol"):
            get_protocol_members(object())
        with self.assertRaisesRegex(TypeError, "not a Protocol"):
            get_protocol_members(Protocol)
        with self.assertRaisesRegex(TypeError, "not a Protocol"):
            get_protocol_members(Generic)

        class P(Protocol):
            a: int
            def b(self) -> str: ...
            @property
            def c(self) -> int: ...

        self.assertEqual(get_protocol_members(P), {'a', 'b', 'c'})
        self.assertIsInstance(get_protocol_members(P), frozenset)
        self.assertIsNot(get_protocol_members(P), P.__protocol_attrs__)

        class Concrete:
            a: int
            def b(self) -> str: return "capybara"
            @property
            def c(self) -> int: return 5

        with self.assertRaisesRegex(TypeError, "not a Protocol"):
            get_protocol_members(Concrete)
        with self.assertRaisesRegex(TypeError, "not a Protocol"):
            get_protocol_members(Concrete())

        class ConcreteInherit(P):
            a: int = 42
            def b(self) -> str: return "capybara"
            @property
            def c(self) -> int: return 5

        with self.assertRaisesRegex(TypeError, "not a Protocol"):
            get_protocol_members(ConcreteInherit)
        with self.assertRaisesRegex(TypeError, "not a Protocol"):
            get_protocol_members(ConcreteInherit())

    def test_is_protocol(self):
        self.assertTrue(is_protocol(Proto))
        self.assertTrue(is_protocol(Point))
        self.assertFalse(is_protocol(Concrete))
        self.assertFalse(is_protocol(Concrete()))
        self.assertFalse(is_protocol(Generic))
        self.assertFalse(is_protocol(object))

        # Protocol is not itself a protocol
        self.assertFalse(is_protocol(Protocol))

    def test_interaction_with_isinstance_checks_on_superclasses_with_ABCMeta(self):
        # Ensure the cache is empty, or this test won't work correctly
        collections.abc.Sized._abc_registry_clear()

        class Foo(collections.abc.Sized, Protocol): pass

        # gh-105144: this previously raised TypeError
        # if a Protocol subclass of Sized had been created
        # before any isinstance() checks against Sized
        self.assertNotIsInstance(1, collections.abc.Sized)

    def test_interaction_with_isinstance_checks_on_superclasses_with_ABCMeta_2(self):
        # Ensure the cache is empty, or this test won't work correctly
        collections.abc.Sized._abc_registry_clear()

        class Foo(typing.Sized, Protocol): pass

        # gh-105144: this previously raised TypeError
        # if a Protocol subclass of Sized had been created
        # before any isinstance() checks against Sized
        self.assertNotIsInstance(1, typing.Sized)

    def test_empty_protocol_decorated_with_final(self):
        @final
        @runtime_checkable
        class EmptyProtocol(Protocol): ...

        self.assertIsSubclass(object, EmptyProtocol)
        self.assertIsInstance(object(), EmptyProtocol)

    def test_protocol_decorated_with_final_callable_members(self):
        @final
        @runtime_checkable
        class ProtocolWithMethod(Protocol):
            def startswith(self, string: str) -> bool: ...

        self.assertIsSubclass(str, ProtocolWithMethod)
        self.assertNotIsSubclass(int, ProtocolWithMethod)
        self.assertIsInstance('foo', ProtocolWithMethod)
        self.assertNotIsInstance(42, ProtocolWithMethod)

    def test_protocol_decorated_with_final_noncallable_members(self):
        @final
        @runtime_checkable
        class ProtocolWithNonCallableMember(Protocol):
            x: int

        class Foo:
            x = 42

        only_callable_members_please = (
            r"Protocols with non-method members don't support issubclass()"
        )

        with self.assertRaisesRegex(TypeError, only_callable_members_please):
            issubclass(Foo, ProtocolWithNonCallableMember)

        with self.assertRaisesRegex(TypeError, only_callable_members_please):
            issubclass(int, ProtocolWithNonCallableMember)

        self.assertIsInstance(Foo(), ProtocolWithNonCallableMember)
        self.assertNotIsInstance(42, ProtocolWithNonCallableMember)

    def test_protocol_decorated_with_final_mixed_members(self):
        @final
        @runtime_checkable
        class ProtocolWithMixedMembers(Protocol):
            x: int
            def method(self) -> None: ...

        class Foo:
            x = 42
            def method(self) -> None: ...

        only_callable_members_please = (
            r"Protocols with non-method members don't support issubclass()"
        )

        with self.assertRaisesRegex(TypeError, only_callable_members_please):
            issubclass(Foo, ProtocolWithMixedMembers)

        with self.assertRaisesRegex(TypeError, only_callable_members_please):
            issubclass(int, ProtocolWithMixedMembers)

        self.assertIsInstance(Foo(), ProtocolWithMixedMembers)
        self.assertNotIsInstance(42, ProtocolWithMixedMembers)

    def test_protocol_issubclass_error_message(self):
        @runtime_checkable
        class Vec2D(Protocol):
            x: float
            y: float

            def square_norm(self) -> float:
                return self.x ** 2 + self.y ** 2

        self.assertEqual(Vec2D.__protocol_attrs__, {'x', 'y', 'square_norm'})
        expected_error_message = (
            "Protocols with non-method members don't support issubclass()."
            " Non-method members: 'x', 'y'."
        )
        with self.assertRaisesRegex(TypeError, re.escape(expected_error_message)):
            issubclass(int, Vec2D)

    def test_nonruntime_protocol_interaction_with_evil_classproperty(self):
        class classproperty:
            def __get__(self, instance, type):
                raise RuntimeError("NO")

        class Commentable(Protocol):
            evil = classproperty()

        # recognised as a protocol attr,
        # but not actually accessed by the protocol metaclass
        # (which would raise RuntimeError) for non-runtime protocols.
        # See gh-113320
        self.assertEqual(get_protocol_members(Commentable), {"evil"})

    def test_runtime_protocol_interaction_with_evil_classproperty(self):
        class CustomError(Exception): pass

        class classproperty:
            def __get__(self, instance, type):
                raise CustomError

        with self.assertRaises(TypeError) as cm:
            @runtime_checkable
            class Commentable(Protocol):
                evil = classproperty()

        exc = cm.exception
        self.assertEqual(
            exc.args[0],
            "Failed to determine whether protocol member 'evil' is a method member"
        )
        self.assertIs(type(exc.__cause__), CustomError)


class GenericTests(BaseTestCase):

    def test_basics(self):
        X = SimpleMapping[str, Any]
        self.assertEqual(X.__parameters__, ())
        with self.assertRaises(TypeError):
            X[str]
        with self.assertRaises(TypeError):
            X[str, str]
        Y = SimpleMapping[XK, str]
        self.assertEqual(Y.__parameters__, (XK,))
        Y[str]
        with self.assertRaises(TypeError):
            Y[str, str]
        SM1 = SimpleMapping[str, int]
        with self.assertRaises(TypeError):
            issubclass(SM1, SimpleMapping)
        self.assertIsInstance(SM1(), SimpleMapping)
        T = TypeVar("T")
        self.assertEqual(List[list[T] | float].__parameters__, (T,))

    def test_generic_errors(self):
        T = TypeVar('T')
        S = TypeVar('S')
        with self.assertRaises(TypeError):
            Generic[T][T]
        with self.assertRaises(TypeError):
            Generic[T][S]
        with self.assertRaises(TypeError):
            class C(Generic[T], Generic[T]): ...
        with self.assertRaises(TypeError):
            isinstance([], List[int])
        with self.assertRaises(TypeError):
            issubclass(list, List[int])
        with self.assertRaises(TypeError):
            class NewGeneric(Generic): ...
        with self.assertRaises(TypeError):
            class MyGeneric(Generic[T], Generic[S]): ...
        with self.assertRaises(TypeError):
            class MyGeneric2(List[T], Generic[S]): ...
        with self.assertRaises(TypeError):
            Generic[()]
        class D(Generic[T]): pass
        with self.assertRaises(TypeError):
            D[()]

    def test_generic_subclass_checks(self):
        for typ in [list[int], List[int],
                    tuple[int, str], Tuple[int, str],
                    typing.Callable[..., None],
                    collections.abc.Callable[..., None]]:
            with self.subTest(typ=typ):
                self.assertRaises(TypeError, issubclass, typ, object)
                self.assertRaises(TypeError, issubclass, typ, type)
                self.assertRaises(TypeError, issubclass, typ, typ)
                self.assertRaises(TypeError, issubclass, object, typ)

                # isinstance is fine:
                self.assertTrue(isinstance(typ, object))
                # but, not when the right arg is also a generic:
                self.assertRaises(TypeError, isinstance, typ, typ)

    def test_init(self):
        T = TypeVar('T')
        S = TypeVar('S')
        with self.assertRaises(TypeError):
            Generic[T, T]
        with self.assertRaises(TypeError):
            Generic[T, S, T]

    def test_init_subclass(self):
        class X(typing.Generic[T]):
            def __init_subclass__(cls, **kwargs):
                super().__init_subclass__(**kwargs)
                cls.attr = 42
        class Y(X):
            pass
        self.assertEqual(Y.attr, 42)
        with self.assertRaises(AttributeError):
            X.attr
        X.attr = 1
        Y.attr = 2
        class Z(Y):
            pass
        class W(X[int]):
            pass
        self.assertEqual(Y.attr, 2)
        self.assertEqual(Z.attr, 42)
        self.assertEqual(W.attr, 42)

    def test_repr(self):
        self.assertEqual(repr(SimpleMapping),
                         f"<class '{__name__}.SimpleMapping'>")
        self.assertEqual(repr(MySimpleMapping),
                         f"<class '{__name__}.MySimpleMapping'>")

    def test_chain_repr(self):
        T = TypeVar('T')
        S = TypeVar('S')

        class C(Generic[T]):
            pass

        X = C[Tuple[S, T]]
        self.assertEqual(X, C[Tuple[S, T]])
        self.assertNotEqual(X, C[Tuple[T, S]])

        Y = X[T, int]
        self.assertEqual(Y, X[T, int])
        self.assertNotEqual(Y, X[S, int])
        self.assertNotEqual(Y, X[T, str])

        Z = Y[str]
        self.assertEqual(Z, Y[str])
        self.assertNotEqual(Z, Y[int])
        self.assertNotEqual(Z, Y[T])

        self.assertTrue(str(Z).endswith(
            '.C[typing.Tuple[str, int]]'))

    def test_new_repr(self):
        T = TypeVar('T')
        U = TypeVar('U', covariant=True)
        S = TypeVar('S')

        self.assertEqual(repr(List), 'typing.List')
        self.assertEqual(repr(List[T]), 'typing.List[~T]')
        self.assertEqual(repr(List[U]), 'typing.List[+U]')
        self.assertEqual(repr(List[S][T][int]), 'typing.List[int]')
        self.assertEqual(repr(List[int]), 'typing.List[int]')

    def test_new_repr_complex(self):
        T = TypeVar('T')
        TS = TypeVar('TS')

        self.assertEqual(repr(typing.Mapping[T, TS][TS, T]), 'typing.Mapping[~TS, ~T]')
        self.assertEqual(repr(List[Tuple[T, TS]][int, T]),
                         'typing.List[typing.Tuple[int, ~T]]')
        self.assertEqual(
            repr(List[Tuple[T, T]][List[int]]),
            'typing.List[typing.Tuple[typing.List[int], typing.List[int]]]'
        )

    def test_new_repr_bare(self):
        T = TypeVar('T')
        self.assertEqual(repr(Generic[T]), 'typing.Generic[~T]')
        self.assertEqual(repr(typing.Protocol[T]), 'typing.Protocol[~T]')
        class C(typing.Dict[Any, Any]): ...
        # this line should just work
        repr(C.__mro__)

    def test_dict(self):
        T = TypeVar('T')

        class B(Generic[T]):
            pass

        b = B()
        b.foo = 42
        self.assertEqual(b.__dict__, {'foo': 42})

        class C(B[int]):
            pass

        c = C()
        c.bar = 'abc'
        self.assertEqual(c.__dict__, {'bar': 'abc'})

    def test_setattr_exceptions(self):
        class Immutable[T]:
            def __setattr__(self, key, value):
                raise RuntimeError("immutable")

        # gh-115165: This used to cause RuntimeError to be raised
        # when we tried to set `__orig_class__` on the `Immutable` instance
        # returned by the `Immutable[int]()` call
        self.assertIsInstance(Immutable[int](), Immutable)

    def test_subscripted_generics_as_proxies(self):
        T = TypeVar('T')
        class C(Generic[T]):
            x = 'def'
        self.assertEqual(C[int].x, 'def')
        self.assertEqual(C[C[int]].x, 'def')
        C[C[int]].x = 'changed'
        self.assertEqual(C.x, 'changed')
        self.assertEqual(C[str].x, 'changed')
        C[List[str]].z = 'new'
        self.assertEqual(C.z, 'new')
        self.assertEqual(C[Tuple[int]].z, 'new')

        self.assertEqual(C().x, 'changed')
        self.assertEqual(C[Tuple[str]]().z, 'new')

        class D(C[T]):
            pass
        self.assertEqual(D[int].x, 'changed')
        self.assertEqual(D.z, 'new')
        D.z = 'from derived z'
        D[int].x = 'from derived x'
        self.assertEqual(C.x, 'changed')
        self.assertEqual(C[int].z, 'new')
        self.assertEqual(D.x, 'from derived x')
        self.assertEqual(D[str].z, 'from derived z')

    def test_abc_registry_kept(self):
        T = TypeVar('T')
        class C(collections.abc.Mapping, Generic[T]): ...
        C.register(int)
        self.assertIsInstance(1, C)
        C[int]
        self.assertIsInstance(1, C)
        C._abc_registry_clear()
        C._abc_caches_clear()  # To keep refleak hunting mode clean

    def test_false_subclasses(self):
        class MyMapping(MutableMapping[str, str]): pass
        self.assertNotIsInstance({}, MyMapping)
        self.assertNotIsSubclass(dict, MyMapping)

    def test_abc_bases(self):
        class MM(MutableMapping[str, str]):
            def __getitem__(self, k):
                return None
            def __setitem__(self, k, v):
                pass
            def __delitem__(self, k):
                pass
            def __iter__(self):
                return iter(())
            def __len__(self):
                return 0
        # this should just work
        MM().update()
        self.assertIsInstance(MM(), collections.abc.MutableMapping)
        self.assertIsInstance(MM(), MutableMapping)
        self.assertNotIsInstance(MM(), List)
        self.assertNotIsInstance({}, MM)

    def test_multiple_bases(self):
        class MM1(MutableMapping[str, str], collections.abc.MutableMapping):
            pass
        class MM2(collections.abc.MutableMapping, MutableMapping[str, str]):
            pass
        self.assertEqual(MM2.__bases__, (collections.abc.MutableMapping, Generic))

    def test_orig_bases(self):
        T = TypeVar('T')
        class C(typing.Dict[str, T]): ...
        self.assertEqual(C.__orig_bases__, (typing.Dict[str, T],))

    def test_naive_runtime_checks(self):
        def naive_dict_check(obj, tp):
            # Check if a dictionary conforms to Dict type
            if len(tp.__parameters__) > 0:
                raise NotImplementedError
            if tp.__args__:
                KT, VT = tp.__args__
                return all(
                    isinstance(k, KT) and isinstance(v, VT)
                    for k, v in obj.items()
                )
        self.assertTrue(naive_dict_check({'x': 1}, typing.Dict[str, int]))
        self.assertFalse(naive_dict_check({1: 'x'}, typing.Dict[str, int]))
        with self.assertRaises(NotImplementedError):
            naive_dict_check({1: 'x'}, typing.Dict[str, T])

        def naive_generic_check(obj, tp):
            # Check if an instance conforms to the generic class
            if not hasattr(obj, '__orig_class__'):
                raise NotImplementedError
            return obj.__orig_class__ == tp
        class Node(Generic[T]): ...
        self.assertTrue(naive_generic_check(Node[int](), Node[int]))
        self.assertFalse(naive_generic_check(Node[str](), Node[int]))
        self.assertFalse(naive_generic_check(Node[str](), List))
        with self.assertRaises(NotImplementedError):
            naive_generic_check([1, 2, 3], Node[int])

        def naive_list_base_check(obj, tp):
            # Check if list conforms to a List subclass
            return all(isinstance(x, tp.__orig_bases__[0].__args__[0])
                       for x in obj)
        class C(List[int]): ...
        self.assertTrue(naive_list_base_check([1, 2, 3], C))
        self.assertFalse(naive_list_base_check(['a', 'b'], C))

    def test_multi_subscr_base(self):
        T = TypeVar('T')
        U = TypeVar('U')
        V = TypeVar('V')
        class C(List[T][U][V]): ...
        class D(C, List[T][U][V]): ...
        self.assertEqual(C.__parameters__, (V,))
        self.assertEqual(D.__parameters__, (V,))
        self.assertEqual(C[int].__parameters__, ())
        self.assertEqual(D[int].__parameters__, ())
        self.assertEqual(C[int].__args__, (int,))
        self.assertEqual(D[int].__args__, (int,))
        self.assertEqual(C.__bases__, (list, Generic))
        self.assertEqual(D.__bases__, (C, list, Generic))
        self.assertEqual(C.__orig_bases__, (List[T][U][V],))
        self.assertEqual(D.__orig_bases__, (C, List[T][U][V]))

    def test_subscript_meta(self):
        T = TypeVar('T')
        class Meta(type): ...
        self.assertEqual(Type[Meta], Type[Meta])
        self.assertEqual(Union[T, int][Meta], Union[Meta, int])
        self.assertEqual(Callable[..., Meta].__args__, (Ellipsis, Meta))

    def test_generic_hashes(self):
        class A(Generic[T]):
            ...

        class B(Generic[T]):
            class A(Generic[T]):
                ...

        self.assertEqual(A, A)
        self.assertEqual(mod_generics_cache.A[str], mod_generics_cache.A[str])
        self.assertEqual(B.A, B.A)
        self.assertEqual(mod_generics_cache.B.A[B.A[str]],
                         mod_generics_cache.B.A[B.A[str]])

        self.assertNotEqual(A, B.A)
        self.assertNotEqual(A, mod_generics_cache.A)
        self.assertNotEqual(A, mod_generics_cache.B.A)
        self.assertNotEqual(B.A, mod_generics_cache.A)
        self.assertNotEqual(B.A, mod_generics_cache.B.A)

        self.assertNotEqual(A[str], B.A[str])
        self.assertNotEqual(A[List[Any]], B.A[List[Any]])
        self.assertNotEqual(A[str], mod_generics_cache.A[str])
        self.assertNotEqual(A[str], mod_generics_cache.B.A[str])
        self.assertNotEqual(B.A[int], mod_generics_cache.A[int])
        self.assertNotEqual(B.A[List[Any]], mod_generics_cache.B.A[List[Any]])

        self.assertNotEqual(Tuple[A[str]], Tuple[B.A[str]])
        self.assertNotEqual(Tuple[A[List[Any]]], Tuple[B.A[List[Any]]])
        self.assertNotEqual(Union[str, A[str]], Union[str, mod_generics_cache.A[str]])
        self.assertNotEqual(Union[A[str], A[str]],
                            Union[A[str], mod_generics_cache.A[str]])
        self.assertNotEqual(typing.FrozenSet[A[str]],
                            typing.FrozenSet[mod_generics_cache.B.A[str]])

        self.assertTrue(repr(Tuple[A[str]]).endswith('<locals>.A[str]]'))
        self.assertTrue(repr(Tuple[B.A[str]]).endswith('<locals>.B.A[str]]'))
        self.assertTrue(repr(Tuple[mod_generics_cache.A[str]])
                        .endswith('mod_generics_cache.A[str]]'))
        self.assertTrue(repr(Tuple[mod_generics_cache.B.A[str]])
                        .endswith('mod_generics_cache.B.A[str]]'))

    def test_extended_generic_rules_eq(self):
        T = TypeVar('T')
        U = TypeVar('U')
        self.assertEqual(Tuple[T, T][int], Tuple[int, int])
        self.assertEqual(typing.Iterable[Tuple[T, T]][T], typing.Iterable[Tuple[T, T]])
        with self.assertRaises(TypeError):
            Tuple[T, int][()]

        self.assertEqual(Union[T, int][int], int)
        self.assertEqual(Union[T, U][int, Union[int, str]], Union[int, str])
        class Base: ...
        class Derived(Base): ...
        self.assertEqual(Union[T, Base][Union[Base, Derived]], Union[Base, Derived])
        self.assertEqual(Callable[[T], T][KT], Callable[[KT], KT])
        self.assertEqual(Callable[..., List[T]][int], Callable[..., List[int]])

    def test_extended_generic_rules_repr(self):
        T = TypeVar('T')
        self.assertEqual(repr(Union[Tuple, Callable]).replace('typing.', ''),
                         'Union[Tuple, Callable]')
        self.assertEqual(repr(Union[Tuple, Tuple[int]]).replace('typing.', ''),
                         'Union[Tuple, Tuple[int]]')
        self.assertEqual(repr(Callable[..., Optional[T]][int]).replace('typing.', ''),
                         'Callable[..., Optional[int]]')
        self.assertEqual(repr(Callable[[], List[T]][int]).replace('typing.', ''),
                         'Callable[[], List[int]]')

    def test_generic_forward_ref(self):
        def foobar(x: List[List['CC']]): ...
        def foobar2(x: list[list[ForwardRef('CC')]]): ...
        def foobar3(x: list[ForwardRef('CC | int')] | int): ...
        class CC: ...
        self.assertEqual(
            get_type_hints(foobar, globals(), locals()),
            {'x': List[List[CC]]}
        )
        self.assertEqual(
            get_type_hints(foobar2, globals(), locals()),
            {'x': list[list[CC]]}
        )
        self.assertEqual(
            get_type_hints(foobar3, globals(), locals()),
            {'x': list[CC | int] | int}
        )

        T = TypeVar('T')
        AT = Tuple[T, ...]
        def barfoo(x: AT): ...
        self.assertIs(get_type_hints(barfoo, globals(), locals())['x'], AT)
        CT = Callable[..., List[T]]
        def barfoo2(x: CT): ...
        self.assertIs(get_type_hints(barfoo2, globals(), locals())['x'], CT)

    def test_generic_pep585_forward_ref(self):
        # See https://bugs.python.org/issue41370

        class C1:
            a: list['C1']
        self.assertEqual(
            get_type_hints(C1, globals(), locals()),
            {'a': list[C1]}
        )

        class C2:
            a: dict['C1', list[List[list['C2']]]]
        self.assertEqual(
            get_type_hints(C2, globals(), locals()),
            {'a': dict[C1, list[List[list[C2]]]]}
        )

        # Test stringified annotations
        scope = {}
        exec(textwrap.dedent('''
        from __future__ import annotations
        class C3:
            a: List[list["C2"]]
        '''), scope)
        C3 = scope['C3']
        self.assertEqual(C3.__annotations__['a'], "List[list['C2']]")
        self.assertEqual(
            get_type_hints(C3, globals(), locals()),
            {'a': List[list[C2]]}
        )

        # Test recursive types
        X = list["X"]
        def f(x: X): ...
        self.assertEqual(
            get_type_hints(f, globals(), locals()),
            {'x': list[list[ForwardRef('X')]]}
        )

    def test_pep695_generic_class_with_future_annotations(self):
        original_globals = dict(ann_module695.__dict__)

        hints_for_A = get_type_hints(ann_module695.A)
        A_type_params = ann_module695.A.__type_params__
        self.assertIs(hints_for_A["x"], A_type_params[0])
        self.assertEqual(hints_for_A["y"].__args__[0], Unpack[A_type_params[1]])
        self.assertIs(hints_for_A["z"].__args__[0], A_type_params[2])

        # should not have changed as a result of the get_type_hints() calls!
        self.assertEqual(ann_module695.__dict__, original_globals)

    def test_pep695_generic_class_with_future_annotations_and_local_shadowing(self):
        hints_for_B = get_type_hints(ann_module695.B)
        self.assertEqual(hints_for_B, {"x": int, "y": str, "z": bytes})

    def test_pep695_generic_class_with_future_annotations_name_clash_with_global_vars(self):
        hints_for_C = get_type_hints(ann_module695.C)
        self.assertEqual(
            set(hints_for_C.values()),
            set(ann_module695.C.__type_params__)
        )

    def test_pep_695_generic_function_with_future_annotations(self):
        hints_for_generic_function = get_type_hints(ann_module695.generic_function)
        func_t_params = ann_module695.generic_function.__type_params__
        self.assertEqual(
            hints_for_generic_function.keys(), {"x", "y", "z", "zz", "return"}
        )
        self.assertIs(hints_for_generic_function["x"], func_t_params[0])
        self.assertEqual(hints_for_generic_function["y"], Unpack[func_t_params[1]])
        self.assertIs(hints_for_generic_function["z"].__origin__, func_t_params[2])
        self.assertIs(hints_for_generic_function["zz"].__origin__, func_t_params[2])

    def test_pep_695_generic_function_with_future_annotations_name_clash_with_global_vars(self):
        self.assertEqual(
            set(get_type_hints(ann_module695.generic_function_2).values()),
            set(ann_module695.generic_function_2.__type_params__)
        )

    def test_pep_695_generic_method_with_future_annotations(self):
        hints_for_generic_method = get_type_hints(ann_module695.D.generic_method)
        params = {
            param.__name__: param
            for param in ann_module695.D.generic_method.__type_params__
        }
        self.assertEqual(
            hints_for_generic_method,
            {"x": params["Foo"], "y": params["Bar"], "return": types.NoneType}
        )

    def test_pep_695_generic_method_with_future_annotations_name_clash_with_global_vars(self):
        self.assertEqual(
            set(get_type_hints(ann_module695.D.generic_method_2).values()),
            set(ann_module695.D.generic_method_2.__type_params__)
        )

    def test_pep_695_generics_with_future_annotations_nested_in_function(self):
        results = ann_module695.nested()

        self.assertEqual(
            set(results.hints_for_E.values()),
            set(results.E.__type_params__)
        )
        self.assertEqual(
            set(results.hints_for_E_meth.values()),
            set(results.E.generic_method.__type_params__)
        )
        self.assertNotEqual(
            set(results.hints_for_E_meth.values()),
            set(results.E.__type_params__)
        )
        self.assertEqual(
            set(results.hints_for_E_meth.values()).intersection(results.E.__type_params__),
            set()
        )

        self.assertEqual(
            set(results.hints_for_generic_func.values()),
            set(results.generic_func.__type_params__)
        )

    def test_extended_generic_rules_subclassing(self):
        class T1(Tuple[T, KT]): ...
        class T2(Tuple[T, ...]): ...
        class C1(typing.Container[T]):
            def __contains__(self, item):
                return False

        self.assertEqual(T1.__parameters__, (T, KT))
        self.assertEqual(T1[int, str].__args__, (int, str))
        self.assertEqual(T1[int, T].__origin__, T1)

        self.assertEqual(T2.__parameters__, (T,))
        # These don't work because of tuple.__class_item__
        ## with self.assertRaises(TypeError):
        ##     T1[int]
        ## with self.assertRaises(TypeError):
        ##     T2[int, str]

        self.assertEqual(repr(C1[int]).split('.')[-1], 'C1[int]')
        self.assertEqual(C1.__parameters__, (T,))
        self.assertIsInstance(C1(), collections.abc.Container)
        self.assertIsSubclass(C1, collections.abc.Container)
        self.assertIsInstance(T1(), tuple)
        self.assertIsSubclass(T2, tuple)
        with self.assertRaises(TypeError):
            issubclass(Tuple[int, ...], typing.Sequence)
        with self.assertRaises(TypeError):
            issubclass(Tuple[int, ...], typing.Iterable)

    def test_fail_with_bare_union(self):
        with self.assertRaises(TypeError):
            List[Union]
        with self.assertRaises(TypeError):
            Tuple[Optional]
        with self.assertRaises(TypeError):
            List[ClassVar[int]]

    def test_fail_with_bare_generic(self):
        T = TypeVar('T')
        with self.assertRaises(TypeError):
            List[Generic]
        with self.assertRaises(TypeError):
            Tuple[Generic[T]]
        with self.assertRaises(TypeError):
            List[typing.Protocol]

    def test_type_erasure_special(self):
        T = TypeVar('T')
        # this is the only test that checks type caching
        self.clear_caches()
        class MyTup(Tuple[T, T]): ...
        self.assertIs(MyTup[int]().__class__, MyTup)
        self.assertEqual(MyTup[int]().__orig_class__, MyTup[int])
        class MyDict(typing.Dict[T, T]): ...
        self.assertIs(MyDict[int]().__class__, MyDict)
        self.assertEqual(MyDict[int]().__orig_class__, MyDict[int])
        class MyDef(typing.DefaultDict[str, T]): ...
        self.assertIs(MyDef[int]().__class__, MyDef)
        self.assertEqual(MyDef[int]().__orig_class__, MyDef[int])
        class MyChain(typing.ChainMap[str, T]): ...
        self.assertIs(MyChain[int]().__class__, MyChain)
        self.assertEqual(MyChain[int]().__orig_class__, MyChain[int])

    def test_all_repr_eq_any(self):
        objs = (getattr(typing, el) for el in typing.__all__)
        for obj in objs:
            self.assertNotEqual(repr(obj), '')
            self.assertEqual(obj, obj)
            if (getattr(obj, '__parameters__', None)
                    and not isinstance(obj, typing.TypeVar)
                    and isinstance(obj.__parameters__, tuple)
                    and len(obj.__parameters__) == 1):
                self.assertEqual(obj[Any].__args__, (Any,))
            if isinstance(obj, type):
                for base in obj.__mro__:
                    self.assertNotEqual(repr(base), '')
                    self.assertEqual(base, base)

    def test_pickle(self):
        global C  # pickle wants to reference the class by name
        T = TypeVar('T')

        class B(Generic[T]):
            pass

        class C(B[int]):
            pass

        c = C()
        c.foo = 42
        c.bar = 'abc'
        for proto in range(pickle.HIGHEST_PROTOCOL + 1):
            z = pickle.dumps(c, proto)
            x = pickle.loads(z)
            self.assertEqual(x.foo, 42)
            self.assertEqual(x.bar, 'abc')
            self.assertEqual(x.__dict__, {'foo': 42, 'bar': 'abc'})
        samples = [Any, Union, Tuple, Callable, ClassVar,
                   Union[int, str], ClassVar[List], Tuple[int, ...], Tuple[()],
                   Callable[[str], bytes],
                   typing.DefaultDict, typing.FrozenSet[int]]
        for s in samples:
            for proto in range(pickle.HIGHEST_PROTOCOL + 1):
                z = pickle.dumps(s, proto)
                x = pickle.loads(z)
                self.assertEqual(s, x)
        more_samples = [List, typing.Iterable, typing.Type, List[int],
                        typing.Type[typing.Mapping], typing.AbstractSet[Tuple[int, str]]]
        for s in more_samples:
            for proto in range(pickle.HIGHEST_PROTOCOL + 1):
                z = pickle.dumps(s, proto)
                x = pickle.loads(z)
                self.assertEqual(s, x)

    def test_copy_and_deepcopy(self):
        T = TypeVar('T')
        class Node(Generic[T]): ...
        things = [Union[T, int], Tuple[T, int], Tuple[()],
                  Callable[..., T], Callable[[int], int],
                  Tuple[Any, Any], Node[T], Node[int], Node[Any], typing.Iterable[T],
                  typing.Iterable[Any], typing.Iterable[int], typing.Dict[int, str],
                  typing.Dict[T, Any], ClassVar[int], ClassVar[List[T]], Tuple['T', 'T'],
                  Union['T', int], List['T'], typing.Mapping['T', int]]
        for t in things + [Any]:
            self.assertEqual(t, copy(t))
            self.assertEqual(t, deepcopy(t))

    def test_immutability_by_copy_and_pickle(self):
        # Special forms like Union, Any, etc., generic aliases to containers like List,
        # Mapping, etc., and type variabcles are considered immutable by copy and pickle.
        global TP, TPB, TPV, PP  # for pickle
        TP = TypeVar('TP')
        TPB = TypeVar('TPB', bound=int)
        TPV = TypeVar('TPV', bytes, str)
        PP = ParamSpec('PP')
        for X in [TP, TPB, TPV, PP,
                  List, typing.Mapping, ClassVar, typing.Iterable,
                  Union, Any, Tuple, Callable]:
            with self.subTest(thing=X):
                self.assertIs(copy(X), X)
                self.assertIs(deepcopy(X), X)
                for proto in range(pickle.HIGHEST_PROTOCOL + 1):
                    self.assertIs(pickle.loads(pickle.dumps(X, proto)), X)
        del TP, TPB, TPV, PP

        # Check that local type variables are copyable.
        TL = TypeVar('TL')
        TLB = TypeVar('TLB', bound=int)
        TLV = TypeVar('TLV', bytes, str)
        PL = ParamSpec('PL')
        for X in [TL, TLB, TLV, PL]:
            with self.subTest(thing=X):
                self.assertIs(copy(X), X)
                self.assertIs(deepcopy(X), X)

    def test_copy_generic_instances(self):
        T = TypeVar('T')
        class C(Generic[T]):
            def __init__(self, attr: T) -> None:
                self.attr = attr

        c = C(42)
        self.assertEqual(copy(c).attr, 42)
        self.assertEqual(deepcopy(c).attr, 42)
        self.assertIsNot(copy(c), c)
        self.assertIsNot(deepcopy(c), c)
        c.attr = 1
        self.assertEqual(copy(c).attr, 1)
        self.assertEqual(deepcopy(c).attr, 1)
        ci = C[int](42)
        self.assertEqual(copy(ci).attr, 42)
        self.assertEqual(deepcopy(ci).attr, 42)
        self.assertIsNot(copy(ci), ci)
        self.assertIsNot(deepcopy(ci), ci)
        ci.attr = 1
        self.assertEqual(copy(ci).attr, 1)
        self.assertEqual(deepcopy(ci).attr, 1)
        self.assertEqual(ci.__orig_class__, C[int])

    def test_weakref_all(self):
        T = TypeVar('T')
        things = [Any, Union[T, int], Callable[..., T], Tuple[Any, Any],
                  Optional[List[int]], typing.Mapping[int, str],
                  typing.Match[bytes], typing.Iterable['whatever']]
        for t in things:
            self.assertEqual(weakref.ref(t)(), t)

    def test_parameterized_slots(self):
        T = TypeVar('T')
        class C(Generic[T]):
            __slots__ = ('potato',)

        c = C()
        c_int = C[int]()

        c.potato = 0
        c_int.potato = 0
        with self.assertRaises(AttributeError):
            c.tomato = 0
        with self.assertRaises(AttributeError):
            c_int.tomato = 0

        def foo(x: C['C']): ...
        self.assertEqual(get_type_hints(foo, globals(), locals())['x'], C[C])
        self.assertEqual(copy(C[int]), deepcopy(C[int]))

    def test_parameterized_slots_dict(self):
        T = TypeVar('T')
        class D(Generic[T]):
            __slots__ = {'banana': 42}

        d = D()
        d_int = D[int]()

        d.banana = 'yes'
        d_int.banana = 'yes'
        with self.assertRaises(AttributeError):
            d.foobar = 'no'
        with self.assertRaises(AttributeError):
            d_int.foobar = 'no'

    def test_errors(self):
        with self.assertRaises(TypeError):
            B = SimpleMapping[XK, Any]

            class C(Generic[B]):
                pass

    def test_repr_2(self):
        class C(Generic[T]):
            pass

        self.assertEqual(C.__module__, __name__)
        self.assertEqual(C.__qualname__,
                         'GenericTests.test_repr_2.<locals>.C')
        X = C[int]
        self.assertEqual(X.__module__, __name__)
        self.assertEqual(repr(X).split('.')[-1], 'C[int]')

        class Y(C[int]):
            pass

        self.assertEqual(Y.__module__, __name__)
        self.assertEqual(Y.__qualname__,
                         'GenericTests.test_repr_2.<locals>.Y')

    def test_repr_3(self):
        T = TypeVar('T')
        T1 = TypeVar('T1')
        P = ParamSpec('P')
        P2 = ParamSpec('P2')
        Ts = TypeVarTuple('Ts')

        class MyCallable(Generic[P, T]):
            pass

        class DoubleSpec(Generic[P, P2, T]):
            pass

        class TsP(Generic[*Ts, P]):
            pass

        object_to_expected_repr = {
            MyCallable[P, T]:                         "MyCallable[~P, ~T]",
            MyCallable[Concatenate[T1, P], T]:        "MyCallable[typing.Concatenate[~T1, ~P], ~T]",
            MyCallable[[], bool]:                     "MyCallable[[], bool]",
            MyCallable[[int], bool]:                  "MyCallable[[int], bool]",
            MyCallable[[int, str], bool]:             "MyCallable[[int, str], bool]",
            MyCallable[[int, list[int]], bool]:       "MyCallable[[int, list[int]], bool]",
            MyCallable[Concatenate[*Ts, P], T]:       "MyCallable[typing.Concatenate[typing.Unpack[Ts], ~P], ~T]",

            DoubleSpec[P2, P, T]:                     "DoubleSpec[~P2, ~P, ~T]",
            DoubleSpec[[int], [str], bool]:           "DoubleSpec[[int], [str], bool]",
            DoubleSpec[[int, int], [str, str], bool]: "DoubleSpec[[int, int], [str, str], bool]",

            TsP[*Ts, P]:                              "TsP[typing.Unpack[Ts], ~P]",
            TsP[int, str, list[int], []]:             "TsP[int, str, list[int], []]",
            TsP[int, [str, list[int]]]:               "TsP[int, [str, list[int]]]",

            # These lines are just too long to fit:
            MyCallable[Concatenate[*Ts, P], int][int, str, [bool, float]]:
                                                      "MyCallable[[int, str, bool, float], int]",
        }

        for obj, expected_repr in object_to_expected_repr.items():
            with self.subTest(obj=obj, expected_repr=expected_repr):
                self.assertRegex(
                    repr(obj),
                    fr"^{re.escape(MyCallable.__module__)}.*\.{re.escape(expected_repr)}$",
                )

    def test_eq_1(self):
        self.assertEqual(Generic, Generic)
        self.assertEqual(Generic[T], Generic[T])
        self.assertNotEqual(Generic[KT], Generic[VT])

    def test_eq_2(self):

        class A(Generic[T]):
            pass

        class B(Generic[T]):
            pass

        self.assertEqual(A, A)
        self.assertNotEqual(A, B)
        self.assertEqual(A[T], A[T])
        self.assertNotEqual(A[T], B[T])

    def test_multiple_inheritance(self):

        class A(Generic[T, VT]):
            pass

        class B(Generic[KT, T]):
            pass

        class C(A[T, VT], Generic[VT, T, KT], B[KT, T]):
            pass

        self.assertEqual(C.__parameters__, (VT, T, KT))

    def test_multiple_inheritance_special(self):
        S = TypeVar('S')
        class B(Generic[S]): ...
        class C(List[int], B): ...
        self.assertEqual(C.__mro__, (C, list, B, Generic, object))

    def test_multiple_inheritance_non_type_with___mro_entries__(self):
        class GoodEntries:
            def __mro_entries__(self, bases):
                return (object,)

        class A(List[int], GoodEntries()): ...

        self.assertEqual(A.__mro__, (A, list, Generic, object))

    def test_multiple_inheritance_non_type_without___mro_entries__(self):
        # Error should be from the type machinery, not from typing.py
        with self.assertRaisesRegex(TypeError, r"^bases must be types"):
            class A(List[int], object()): ...

    def test_multiple_inheritance_non_type_bad___mro_entries__(self):
        class BadEntries:
            def __mro_entries__(self, bases):
                return None

        # Error should be from the type machinery, not from typing.py
        with self.assertRaisesRegex(
            TypeError,
            r"^__mro_entries__ must return a tuple",
        ):
            class A(List[int], BadEntries()): ...

    def test_multiple_inheritance___mro_entries___returns_non_type(self):
        class BadEntries:
            def __mro_entries__(self, bases):
                return (object(),)

        # Error should be from the type machinery, not from typing.py
        with self.assertRaisesRegex(
            TypeError,
            r"^bases must be types",
        ):
            class A(List[int], BadEntries()): ...

    def test_multiple_inheritance_with_genericalias(self):
        class A(typing.Sized, list[int]): ...

        self.assertEqual(
            A.__mro__,
            (A, collections.abc.Sized, Generic, list, object),
        )

    def test_multiple_inheritance_with_genericalias_2(self):
        T = TypeVar("T")

        class BaseSeq(typing.Sequence[T]): ...
        class MySeq(List[T], BaseSeq[T]): ...

        self.assertEqual(
            MySeq.__mro__,
            (
                MySeq,
                list,
                BaseSeq,
                collections.abc.Sequence,
                collections.abc.Reversible,
                collections.abc.Collection,
                collections.abc.Sized,
                collections.abc.Iterable,
                collections.abc.Container,
                Generic,
                object,
            ),
        )

    def test_init_subclass_super_called(self):
        class FinalException(Exception):
            pass

        class Final:
            def __init_subclass__(cls, **kwargs) -> None:
                for base in cls.__bases__:
                    if base is not Final and issubclass(base, Final):
                        raise FinalException(base)
                super().__init_subclass__(**kwargs)
        class Test(Generic[T], Final):
            pass
        with self.assertRaises(FinalException):
            class Subclass(Test):
                pass
        with self.assertRaises(FinalException):
            class Subclass2(Test[int]):
                pass

    def test_nested(self):

        G = Generic

        class Visitor(G[T]):

            a = None

            def set(self, a: T):
                self.a = a

            def get(self):
                return self.a

            def visit(self) -> T:
                return self.a

        V = Visitor[typing.List[int]]

        class IntListVisitor(V):

            def append(self, x: int):
                self.a.append(x)

        a = IntListVisitor()
        a.set([])
        a.append(1)
        a.append(42)
        self.assertEqual(a.get(), [1, 42])

    def test_type_erasure(self):
        T = TypeVar('T')

        class Node(Generic[T]):
            def __init__(self, label: T,
                         left: 'Node[T]' = None,
                         right: 'Node[T]' = None):
                self.label = label  # type: T
                self.left = left  # type: Optional[Node[T]]
                self.right = right  # type: Optional[Node[T]]

        def foo(x: T):
            a = Node(x)
            b = Node[T](x)
            c = Node[Any](x)
            self.assertIs(type(a), Node)
            self.assertIs(type(b), Node)
            self.assertIs(type(c), Node)
            self.assertEqual(a.label, x)
            self.assertEqual(b.label, x)
            self.assertEqual(c.label, x)

        foo(42)

    def test_implicit_any(self):
        T = TypeVar('T')

        class C(Generic[T]):
            pass

        class D(C):
            pass

        self.assertEqual(D.__parameters__, ())

        with self.assertRaises(TypeError):
            D[int]
        with self.assertRaises(TypeError):
            D[Any]
        with self.assertRaises(TypeError):
            D[T]

    def test_new_with_args(self):

        class A(Generic[T]):
            pass

        class B:
            def __new__(cls, arg):
                # call object
                obj = super().__new__(cls)
                obj.arg = arg
                return obj

        # mro: C, A, Generic, B, object
        class C(A, B):
            pass

        c = C('foo')
        self.assertEqual(c.arg, 'foo')

    def test_new_with_args2(self):

        class A:
            def __init__(self, arg):
                self.from_a = arg
                # call object
                super().__init__()

        # mro: C, Generic, A, object
        class C(Generic[T], A):
            def __init__(self, arg):
                self.from_c = arg
                # call Generic
                super().__init__(arg)

        c = C('foo')
        self.assertEqual(c.from_a, 'foo')
        self.assertEqual(c.from_c, 'foo')

    def test_new_no_args(self):

        class A(Generic[T]):
            pass

        with self.assertRaises(TypeError):
            A('foo')

        class B:
            def __new__(cls):
                # call object
                obj = super().__new__(cls)
                obj.from_b = 'b'
                return obj

        # mro: C, A, Generic, B, object
        class C(A, B):
            def __init__(self, arg):
                self.arg = arg

            def __new__(cls, arg):
                # call A
                obj = super().__new__(cls)
                obj.from_c = 'c'
                return obj

        c = C('foo')
        self.assertEqual(c.arg, 'foo')
        self.assertEqual(c.from_b, 'b')
        self.assertEqual(c.from_c, 'c')

    def test_subclass_special_form(self):
        for obj in (
            ClassVar[int],
            Final[int],
            Union[int, float],
            Optional[int],
            Literal[1, 2],
            Concatenate[int, ParamSpec("P")],
            TypeGuard[int],
            TypeIs[range],
        ):
            with self.subTest(msg=obj):
                with self.assertRaisesRegex(
                        TypeError, f'^{re.escape(f"Cannot subclass {obj!r}")}$'
                ):
                    class Foo(obj):
                        pass

    def test_complex_subclasses(self):
        T_co = TypeVar("T_co", covariant=True)

        class Base(Generic[T_co]):
            ...

        T = TypeVar("T")

        # see gh-94607: this fails in that bug
        class Sub(Base, Generic[T]):
            ...

    def test_parameter_detection(self):
        self.assertEqual(List[T].__parameters__, (T,))
        self.assertEqual(List[List[T]].__parameters__, (T,))
        class A:
            __parameters__ = (T,)
        # Bare classes should be skipped
        for a in (List, list):
            for b in (A, int, TypeVar, TypeVarTuple, ParamSpec, types.GenericAlias, types.UnionType):
                with self.subTest(generic=a, sub=b):
                    with self.assertRaisesRegex(TypeError, '.* is not a generic class'):
                        a[b][str]
        # Duck-typing anything that looks like it has __parameters__.
        # These tests are optional and failure is okay.
        self.assertEqual(List[A()].__parameters__, (T,))
        # C version of GenericAlias
        self.assertEqual(list[A()].__parameters__, (T,))

    def test_non_generic_subscript(self):
        T = TypeVar('T')
        class G(Generic[T]):
            pass
        class A:
            __parameters__ = (T,)

        for s in (int, G, A, List, list,
                  TypeVar, TypeVarTuple, ParamSpec,
                  types.GenericAlias, types.UnionType):

            for t in Tuple, tuple:
                with self.subTest(tuple=t, sub=s):
                    self.assertEqual(t[s, T][int], t[s, int])
                    self.assertEqual(t[T, s][int], t[int, s])
                    a = t[s]
                    with self.assertRaises(TypeError):
                        a[int]

            for c in Callable, collections.abc.Callable:
                with self.subTest(callable=c, sub=s):
                    self.assertEqual(c[[s], T][int], c[[s], int])
                    self.assertEqual(c[[T], s][int], c[[int], s])
                    a = c[[s], s]
                    with self.assertRaises(TypeError):
                        a[int]


class ClassVarTests(BaseTestCase):

    def test_basics(self):
        with self.assertRaises(TypeError):
            ClassVar[int, str]
        with self.assertRaises(TypeError):
            ClassVar[int][str]

    def test_repr(self):
        self.assertEqual(repr(ClassVar), 'typing.ClassVar')
        cv = ClassVar[int]
        self.assertEqual(repr(cv), 'typing.ClassVar[int]')
        cv = ClassVar[Employee]
        self.assertEqual(repr(cv), 'typing.ClassVar[%s.Employee]' % __name__)

    def test_cannot_subclass(self):
        with self.assertRaisesRegex(TypeError, CANNOT_SUBCLASS_TYPE):
            class C(type(ClassVar)):
                pass
        with self.assertRaisesRegex(TypeError, CANNOT_SUBCLASS_TYPE):
            class D(type(ClassVar[int])):
                pass
        with self.assertRaisesRegex(TypeError,
                                    r'Cannot subclass typing\.ClassVar'):
            class E(ClassVar):
                pass
        with self.assertRaisesRegex(TypeError,
                                    r'Cannot subclass typing\.ClassVar\[int\]'):
            class F(ClassVar[int]):
                pass

    def test_cannot_init(self):
        with self.assertRaises(TypeError):
            ClassVar()
        with self.assertRaises(TypeError):
            type(ClassVar)()
        with self.assertRaises(TypeError):
            type(ClassVar[Optional[int]])()

    def test_no_isinstance(self):
        with self.assertRaises(TypeError):
            isinstance(1, ClassVar[int])
        with self.assertRaises(TypeError):
            issubclass(int, ClassVar)

class FinalTests(BaseTestCase):

    def test_basics(self):
        Final[int]  # OK
        with self.assertRaises(TypeError):
            Final[int, str]
        with self.assertRaises(TypeError):
            Final[int][str]
        with self.assertRaises(TypeError):
            Optional[Final[int]]

    def test_repr(self):
        self.assertEqual(repr(Final), 'typing.Final')
        cv = Final[int]
        self.assertEqual(repr(cv), 'typing.Final[int]')
        cv = Final[Employee]
        self.assertEqual(repr(cv), 'typing.Final[%s.Employee]' % __name__)
        cv = Final[tuple[int]]
        self.assertEqual(repr(cv), 'typing.Final[tuple[int]]')

    def test_cannot_subclass(self):
        with self.assertRaisesRegex(TypeError, CANNOT_SUBCLASS_TYPE):
            class C(type(Final)):
                pass
        with self.assertRaisesRegex(TypeError, CANNOT_SUBCLASS_TYPE):
            class D(type(Final[int])):
                pass
        with self.assertRaisesRegex(TypeError,
                r'Cannot subclass typing\.Final'):
            class E(Final):
                pass
        with self.assertRaisesRegex(TypeError,
                r'Cannot subclass typing\.Final\[int\]'):
            class F(Final[int]):
                pass

    def test_cannot_init(self):
        with self.assertRaises(TypeError):
            Final()
        with self.assertRaises(TypeError):
            type(Final)()
        with self.assertRaises(TypeError):
            type(Final[Optional[int]])()

    def test_no_isinstance(self):
        with self.assertRaises(TypeError):
            isinstance(1, Final[int])
        with self.assertRaises(TypeError):
            issubclass(int, Final)


class FinalDecoratorTests(BaseTestCase):
    def test_final_unmodified(self):
        def func(x): ...
        self.assertIs(func, final(func))

    def test_dunder_final(self):
        @final
        def func(): ...
        @final
        class Cls: ...
        self.assertIs(True, func.__final__)
        self.assertIs(True, Cls.__final__)

        class Wrapper:
            __slots__ = ("func",)
            def __init__(self, func):
                self.func = func
            def __call__(self, *args, **kwargs):
                return self.func(*args, **kwargs)

        # Check that no error is thrown if the attribute
        # is not writable.
        @final
        @Wrapper
        def wrapped(): ...
        self.assertIsInstance(wrapped, Wrapper)
        self.assertIs(False, hasattr(wrapped, "__final__"))

        class Meta(type):
            @property
            def __final__(self): return "can't set me"
        @final
        class WithMeta(metaclass=Meta): ...
        self.assertEqual(WithMeta.__final__, "can't set me")

        # Builtin classes throw TypeError if you try to set an
        # attribute.
        final(int)
        self.assertIs(False, hasattr(int, "__final__"))

        # Make sure it works with common builtin decorators
        class Methods:
            @final
            @classmethod
            def clsmethod(cls): ...

            @final
            @staticmethod
            def stmethod(): ...

            # The other order doesn't work because property objects
            # don't allow attribute assignment.
            @property
            @final
            def prop(self): ...

            @final
            @lru_cache()
            def cached(self): ...

        # Use getattr_static because the descriptor returns the
        # underlying function, which doesn't have __final__.
        self.assertIs(
            True,
            inspect.getattr_static(Methods, "clsmethod").__final__
        )
        self.assertIs(
            True,
            inspect.getattr_static(Methods, "stmethod").__final__
        )
        self.assertIs(True, Methods.prop.fget.__final__)
        self.assertIs(True, Methods.cached.__final__)


class OverrideDecoratorTests(BaseTestCase):
    def test_override(self):
        class Base:
            def normal_method(self): ...
            @classmethod
            def class_method_good_order(cls): ...
            @classmethod
            def class_method_bad_order(cls): ...
            @staticmethod
            def static_method_good_order(): ...
            @staticmethod
            def static_method_bad_order(): ...

        class Derived(Base):
            @override
            def normal_method(self):
                return 42

            @classmethod
            @override
            def class_method_good_order(cls):
                return 42
            @override
            @classmethod
            def class_method_bad_order(cls):
                return 42

            @staticmethod
            @override
            def static_method_good_order():
                return 42
            @override
            @staticmethod
            def static_method_bad_order():
                return 42

        self.assertIsSubclass(Derived, Base)
        instance = Derived()
        self.assertEqual(instance.normal_method(), 42)
        self.assertIs(True, Derived.normal_method.__override__)
        self.assertIs(True, instance.normal_method.__override__)

        self.assertEqual(Derived.class_method_good_order(), 42)
        self.assertIs(True, Derived.class_method_good_order.__override__)
        self.assertEqual(Derived.class_method_bad_order(), 42)
        self.assertIs(False, hasattr(Derived.class_method_bad_order, "__override__"))

        self.assertEqual(Derived.static_method_good_order(), 42)
        self.assertIs(True, Derived.static_method_good_order.__override__)
        self.assertEqual(Derived.static_method_bad_order(), 42)
        self.assertIs(False, hasattr(Derived.static_method_bad_order, "__override__"))

        # Base object is not changed:
        self.assertIs(False, hasattr(Base.normal_method, "__override__"))
        self.assertIs(False, hasattr(Base.class_method_good_order, "__override__"))
        self.assertIs(False, hasattr(Base.class_method_bad_order, "__override__"))
        self.assertIs(False, hasattr(Base.static_method_good_order, "__override__"))
        self.assertIs(False, hasattr(Base.static_method_bad_order, "__override__"))

    def test_property(self):
        class Base:
            @property
            def correct(self) -> int:
                return 1
            @property
            def wrong(self) -> int:
                return 1

        class Child(Base):
            @property
            @override
            def correct(self) -> int:
                return 2
            @override
            @property
            def wrong(self) -> int:
                return 2

        instance = Child()
        self.assertEqual(instance.correct, 2)
        self.assertTrue(Child.correct.fget.__override__)
        self.assertEqual(instance.wrong, 2)
        self.assertFalse(hasattr(Child.wrong, "__override__"))
        self.assertFalse(hasattr(Child.wrong.fset, "__override__"))

    def test_silent_failure(self):
        class CustomProp:
            __slots__ = ('fget',)
            def __init__(self, fget):
                self.fget = fget
            def __get__(self, obj, objtype=None):
                return self.fget(obj)

        class WithOverride:
            @override  # must not fail on object with `__slots__`
            @CustomProp
            def some(self):
                return 1

        self.assertEqual(WithOverride.some, 1)
        self.assertFalse(hasattr(WithOverride.some, "__override__"))

    def test_multiple_decorators(self):
        def with_wraps(f):  # similar to `lru_cache` definition
            @wraps(f)
            def wrapper(*args, **kwargs):
                return f(*args, **kwargs)
            return wrapper

        class WithOverride:
            @override
            @with_wraps
            def on_top(self, a: int) -> int:
                return a + 1
            @with_wraps
            @override
            def on_bottom(self, a: int) -> int:
                return a + 2

        instance = WithOverride()
        self.assertEqual(instance.on_top(1), 2)
        self.assertTrue(instance.on_top.__override__)
        self.assertEqual(instance.on_bottom(1), 3)
        self.assertTrue(instance.on_bottom.__override__)


class CastTests(BaseTestCase):

    def test_basics(self):
        self.assertEqual(cast(int, 42), 42)
        self.assertEqual(cast(float, 42), 42)
        self.assertIs(type(cast(float, 42)), int)
        self.assertEqual(cast(Any, 42), 42)
        self.assertEqual(cast(list, 42), 42)
        self.assertEqual(cast(Union[str, float], 42), 42)
        self.assertEqual(cast(AnyStr, 42), 42)
        self.assertEqual(cast(None, 42), 42)

    def test_errors(self):
        # Bogus calls are not expected to fail.
        cast(42, 42)
        cast('hello', 42)


class AssertTypeTests(BaseTestCase):

    def test_basics(self):
        arg = 42
        self.assertIs(assert_type(arg, int), arg)
        self.assertIs(assert_type(arg, str | float), arg)
        self.assertIs(assert_type(arg, AnyStr), arg)
        self.assertIs(assert_type(arg, None), arg)

    def test_errors(self):
        # Bogus calls are not expected to fail.
        arg = 42
        self.assertIs(assert_type(arg, 42), arg)
        self.assertIs(assert_type(arg, 'hello'), arg)


# We need this to make sure that `@no_type_check` respects `__module__` attr:
from test.typinganndata import ann_module8

@no_type_check
class NoTypeCheck_Outer:
    Inner = ann_module8.NoTypeCheck_Outer.Inner

@no_type_check
class NoTypeCheck_WithFunction:
    NoTypeCheck_function = ann_module8.NoTypeCheck_function


class ForwardRefTests(BaseTestCase):

    def test_basics(self):

        class Node(Generic[T]):

            def __init__(self, label: T):
                self.label = label
                self.left = self.right = None

            def add_both(self,
                         left: 'Optional[Node[T]]',
                         right: 'Node[T]' = None,
                         stuff: int = None,
                         blah=None):
                self.left = left
                self.right = right

            def add_left(self, node: Optional['Node[T]']):
                self.add_both(node, None)

            def add_right(self, node: 'Node[T]' = None):
                self.add_both(None, node)

        t = Node[int]
        both_hints = get_type_hints(t.add_both, globals(), locals())
        self.assertEqual(both_hints['left'], Optional[Node[T]])
        self.assertEqual(both_hints['right'], Node[T])
        self.assertEqual(both_hints['stuff'], int)
        self.assertNotIn('blah', both_hints)

        left_hints = get_type_hints(t.add_left, globals(), locals())
        self.assertEqual(left_hints['node'], Optional[Node[T]])

        right_hints = get_type_hints(t.add_right, globals(), locals())
        self.assertEqual(right_hints['node'], Node[T])

    def test_forwardref_instance_type_error(self):
        fr = typing.ForwardRef('int')
        with self.assertRaises(TypeError):
            isinstance(42, fr)

    def test_forwardref_subclass_type_error(self):
        fr = typing.ForwardRef('int')
        with self.assertRaises(TypeError):
            issubclass(int, fr)

    def test_forwardref_only_str_arg(self):
        with self.assertRaises(TypeError):
            typing.ForwardRef(1)  # only `str` type is allowed

    def test_forward_equality(self):
        fr = typing.ForwardRef('int')
        self.assertEqual(fr, typing.ForwardRef('int'))
        self.assertNotEqual(List['int'], List[int])
        self.assertNotEqual(fr, typing.ForwardRef('int', module=__name__))
        frm = typing.ForwardRef('int', module=__name__)
        self.assertEqual(frm, typing.ForwardRef('int', module=__name__))
        self.assertNotEqual(frm, typing.ForwardRef('int', module='__other_name__'))

    def test_forward_equality_gth(self):
        c1 = typing.ForwardRef('C')
        c1_gth = typing.ForwardRef('C')
        c2 = typing.ForwardRef('C')
        c2_gth = typing.ForwardRef('C')

        class C:
            pass
        def foo(a: c1_gth, b: c2_gth):
            pass

        self.assertEqual(get_type_hints(foo, globals(), locals()), {'a': C, 'b': C})
        self.assertEqual(c1, c2)
        self.assertEqual(c1, c1_gth)
        self.assertEqual(c1_gth, c2_gth)
        self.assertEqual(List[c1], List[c1_gth])
        self.assertNotEqual(List[c1], List[C])
        self.assertNotEqual(List[c1_gth], List[C])
        self.assertEqual(Union[c1, c1_gth], Union[c1])
        self.assertEqual(Union[c1, c1_gth, int], Union[c1, int])

    def test_forward_equality_hash(self):
        c1 = typing.ForwardRef('int')
        c1_gth = typing.ForwardRef('int')
        c2 = typing.ForwardRef('int')
        c2_gth = typing.ForwardRef('int')

        def foo(a: c1_gth, b: c2_gth):
            pass
        get_type_hints(foo, globals(), locals())

        self.assertEqual(hash(c1), hash(c2))
        self.assertEqual(hash(c1_gth), hash(c2_gth))
        self.assertEqual(hash(c1), hash(c1_gth))

        c3 = typing.ForwardRef('int', module=__name__)
        c4 = typing.ForwardRef('int', module='__other_name__')

        self.assertNotEqual(hash(c3), hash(c1))
        self.assertNotEqual(hash(c3), hash(c1_gth))
        self.assertNotEqual(hash(c3), hash(c4))
        self.assertEqual(hash(c3), hash(typing.ForwardRef('int', module=__name__)))

    def test_forward_equality_namespace(self):
        class A:
            pass
        def namespace1():
            a = typing.ForwardRef('A')
            def fun(x: a):
                pass
            get_type_hints(fun, globals(), locals())
            return a

        def namespace2():
            a = typing.ForwardRef('A')

            class A:
                pass
            def fun(x: a):
                pass

            get_type_hints(fun, globals(), locals())
            return a

        self.assertEqual(namespace1(), namespace1())
        self.assertNotEqual(namespace1(), namespace2())

    def test_forward_repr(self):
        self.assertEqual(repr(List['int']), "typing.List[ForwardRef('int')]")
        self.assertEqual(repr(List[ForwardRef('int', module='mod')]),
                         "typing.List[ForwardRef('int', module='mod')]")

    def test_union_forward(self):

        def foo(a: Union['T']):
            pass

        self.assertEqual(get_type_hints(foo, globals(), locals()),
                         {'a': Union[T]})

        def foo(a: tuple[ForwardRef('T')] | int):
            pass

        self.assertEqual(get_type_hints(foo, globals(), locals()),
                         {'a': tuple[T] | int})

    def test_tuple_forward(self):

        def foo(a: Tuple['T']):
            pass

        self.assertEqual(get_type_hints(foo, globals(), locals()),
                         {'a': Tuple[T]})

        def foo(a: tuple[ForwardRef('T')]):
            pass

        self.assertEqual(get_type_hints(foo, globals(), locals()),
                         {'a': tuple[T]})

    def test_double_forward(self):
        def foo(a: 'List[\'int\']'):
            pass
        self.assertEqual(get_type_hints(foo, globals(), locals()),
                         {'a': List[int]})

    def test_forward_recursion_actually(self):
        def namespace1():
            a = typing.ForwardRef('A')
            A = a
            def fun(x: a): pass

            ret = get_type_hints(fun, globals(), locals())
            return a

        def namespace2():
            a = typing.ForwardRef('A')
            A = a
            def fun(x: a): pass

            ret = get_type_hints(fun, globals(), locals())
            return a

        def cmp(o1, o2):
            return o1 == o2

        with infinite_recursion(25):
            r1 = namespace1()
            r2 = namespace2()
            self.assertIsNot(r1, r2)
            self.assertRaises(RecursionError, cmp, r1, r2)

    def test_union_forward_recursion(self):
        ValueList = List['Value']
        Value = Union[str, ValueList]

        class C:
            foo: List[Value]
        class D:
            foo: Union[Value, ValueList]
        class E:
            foo: Union[List[Value], ValueList]
        class F:
            foo: Union[Value, List[Value], ValueList]

        self.assertEqual(get_type_hints(C, globals(), locals()), get_type_hints(C, globals(), locals()))
        self.assertEqual(get_type_hints(C, globals(), locals()),
                         {'foo': List[Union[str, List[Union[str, List['Value']]]]]})
        self.assertEqual(get_type_hints(D, globals(), locals()),
                         {'foo': Union[str, List[Union[str, List['Value']]]]})
        self.assertEqual(get_type_hints(E, globals(), locals()),
                         {'foo': Union[
                             List[Union[str, List[Union[str, List['Value']]]]],
                             List[Union[str, List['Value']]]
                         ]
                          })
        self.assertEqual(get_type_hints(F, globals(), locals()),
                         {'foo': Union[
                             str,
                             List[Union[str, List['Value']]],
                             List[Union[str, List[Union[str, List['Value']]]]]
                         ]
                          })

    def test_callable_forward(self):

        def foo(a: Callable[['T'], 'T']):
            pass

        self.assertEqual(get_type_hints(foo, globals(), locals()),
                         {'a': Callable[[T], T]})

    def test_callable_with_ellipsis_forward(self):

        def foo(a: 'Callable[..., T]'):
            pass

        self.assertEqual(get_type_hints(foo, globals(), locals()),
                         {'a': Callable[..., T]})

    def test_special_forms_forward(self):

        class C:
            a: Annotated['ClassVar[int]', (3, 5)] = 4
            b: Annotated['Final[int]', "const"] = 4
            x: 'ClassVar' = 4
            y: 'Final' = 4

        class CF:
            b: List['Final[int]'] = 4

        self.assertEqual(get_type_hints(C, globals())['a'], ClassVar[int])
        self.assertEqual(get_type_hints(C, globals())['b'], Final[int])
        self.assertEqual(get_type_hints(C, globals())['x'], ClassVar)
        self.assertEqual(get_type_hints(C, globals())['y'], Final)
        with self.assertRaises(TypeError):
            get_type_hints(CF, globals()),

    def test_syntax_error(self):

        with self.assertRaises(SyntaxError):
            Generic['/T']

    def test_delayed_syntax_error(self):

        def foo(a: 'Node[T'):
            pass

        with self.assertRaises(SyntaxError):
            get_type_hints(foo)

    def test_syntax_error_empty_string(self):
        for form in [typing.List, typing.Set, typing.Type, typing.Deque]:
            with self.subTest(form=form):
                with self.assertRaises(SyntaxError):
                    form['']

    def test_name_error(self):

        def foo(a: 'Noode[T]'):
            pass

        with self.assertRaises(NameError):
            get_type_hints(foo, locals())

    def test_no_type_check(self):

        @no_type_check
        def foo(a: 'whatevers') -> {}:
            pass

        th = get_type_hints(foo)
        self.assertEqual(th, {})

    def test_no_type_check_class(self):

        @no_type_check
        class C:
            def foo(a: 'whatevers') -> {}:
                pass

        cth = get_type_hints(C.foo)
        self.assertEqual(cth, {})
        ith = get_type_hints(C().foo)
        self.assertEqual(ith, {})

    def test_no_type_check_no_bases(self):
        class C:
            def meth(self, x: int): ...
        @no_type_check
        class D(C):
            c = C

        # verify that @no_type_check never affects bases
        self.assertEqual(get_type_hints(C.meth), {'x': int})

        # and never child classes:
        class Child(D):
            def foo(self, x: int): ...

        self.assertEqual(get_type_hints(Child.foo), {'x': int})

    def test_no_type_check_nested_types(self):
        # See https://bugs.python.org/issue46571
        class Other:
            o: int
        class B:  # Has the same `__name__`` as `A.B` and different `__qualname__`
            o: int
        @no_type_check
        class A:
            a: int
            class B:
                b: int
                class C:
                    c: int
            class D:
                d: int

            Other = Other

        for klass in [A, A.B, A.B.C, A.D]:
            with self.subTest(klass=klass):
                self.assertTrue(klass.__no_type_check__)
                self.assertEqual(get_type_hints(klass), {})

        for not_modified in [Other, B]:
            with self.subTest(not_modified=not_modified):
                with self.assertRaises(AttributeError):
                    not_modified.__no_type_check__
                self.assertNotEqual(get_type_hints(not_modified), {})

    def test_no_type_check_class_and_static_methods(self):
        @no_type_check
        class Some:
            @staticmethod
            def st(x: int) -> int: ...
            @classmethod
            def cl(cls, y: int) -> int: ...

        self.assertTrue(Some.st.__no_type_check__)
        self.assertEqual(get_type_hints(Some.st), {})
        self.assertTrue(Some.cl.__no_type_check__)
        self.assertEqual(get_type_hints(Some.cl), {})

    def test_no_type_check_other_module(self):
        self.assertTrue(NoTypeCheck_Outer.__no_type_check__)
        with self.assertRaises(AttributeError):
            ann_module8.NoTypeCheck_Outer.__no_type_check__
        with self.assertRaises(AttributeError):
            ann_module8.NoTypeCheck_Outer.Inner.__no_type_check__

        self.assertTrue(NoTypeCheck_WithFunction.__no_type_check__)
        with self.assertRaises(AttributeError):
            ann_module8.NoTypeCheck_function.__no_type_check__

    def test_no_type_check_foreign_functions(self):
        # We should not modify this function:
        def some(*args: int) -> int:
            ...

        @no_type_check
        class A:
            some_alias = some
            some_class = classmethod(some)
            some_static = staticmethod(some)

        with self.assertRaises(AttributeError):
            some.__no_type_check__
        self.assertEqual(get_type_hints(some), {'args': int, 'return': int})

    def test_no_type_check_lambda(self):
        @no_type_check
        class A:
            # Corner case: `lambda` is both an assignment and a function:
            bar: Callable[[int], int] = lambda arg: arg

        self.assertTrue(A.bar.__no_type_check__)
        self.assertEqual(get_type_hints(A.bar), {})

    def test_no_type_check_TypeError(self):
        # This simply should not fail with
        # `TypeError: can't set attributes of built-in/extension type 'dict'`
        no_type_check(dict)

    def test_no_type_check_forward_ref_as_string(self):
        class C:
            foo: typing.ClassVar[int] = 7
        class D:
            foo: ClassVar[int] = 7
        class E:
            foo: 'typing.ClassVar[int]' = 7
        class F:
            foo: 'ClassVar[int]' = 7

        expected_result = {'foo': typing.ClassVar[int]}
        for clazz in [C, D, E, F]:
            self.assertEqual(get_type_hints(clazz), expected_result)

    def test_meta_no_type_check(self):
        depr_msg = (
            "'typing.no_type_check_decorator' is deprecated "
            "and slated for removal in Python 3.15"
        )
        with self.assertWarnsRegex(DeprecationWarning, depr_msg):
            @no_type_check_decorator
            def magic_decorator(func):
                return func

        self.assertEqual(magic_decorator.__name__, 'magic_decorator')

        @magic_decorator
        def foo(a: 'whatevers') -> {}:
            pass

        @magic_decorator
        class C:
            def foo(a: 'whatevers') -> {}:
                pass

        self.assertEqual(foo.__name__, 'foo')
        th = get_type_hints(foo)
        self.assertEqual(th, {})
        cth = get_type_hints(C.foo)
        self.assertEqual(cth, {})
        ith = get_type_hints(C().foo)
        self.assertEqual(ith, {})

    def test_default_globals(self):
        code = ("class C:\n"
                "    def foo(self, a: 'C') -> 'D': pass\n"
                "class D:\n"
                "    def bar(self, b: 'D') -> C: pass\n"
                )
        ns = {}
        exec(code, ns)
        hints = get_type_hints(ns['C'].foo)
        self.assertEqual(hints, {'a': ns['C'], 'return': ns['D']})

    def test_final_forward_ref(self):
        self.assertEqual(gth(Loop, globals())['attr'], Final[Loop])
        self.assertNotEqual(gth(Loop, globals())['attr'], Final[int])
        self.assertNotEqual(gth(Loop, globals())['attr'], Final)

    def test_or(self):
        X = ForwardRef('X')
        # __or__/__ror__ itself
        self.assertEqual(X | "x", Union[X, "x"])
        self.assertEqual("x" | X, Union["x", X])


class InternalsTests(BaseTestCase):
    def test_deprecation_for_no_type_params_passed_to__evaluate(self):
        with self.assertWarnsRegex(
            DeprecationWarning,
            (
                "Failing to pass a value to the 'type_params' parameter "
                "of 'typing._eval_type' is deprecated"
            )
        ) as cm:
            self.assertEqual(typing._eval_type(list["int"], globals(), {}), list[int])

        self.assertEqual(cm.filename, __file__)

        f = ForwardRef("int")

        with self.assertWarnsRegex(
            DeprecationWarning,
            (
                "Failing to pass a value to the 'type_params' parameter "
                "of 'typing.ForwardRef._evaluate' is deprecated"
            )
        ) as cm:
            self.assertIs(f._evaluate(globals(), {}, recursive_guard=frozenset()), int)

        self.assertEqual(cm.filename, __file__)

    def test_collect_parameters(self):
        typing = import_helper.import_fresh_module("typing")
        with self.assertWarnsRegex(
            DeprecationWarning,
            "The private _collect_parameters function is deprecated"
        ) as cm:
            typing._collect_parameters
        self.assertEqual(cm.filename, __file__)


@lru_cache()
def cached_func(x, y):
    return 3 * x + y


class MethodHolder:
    @classmethod
    def clsmethod(cls): ...
    @staticmethod
    def stmethod(): ...
    def method(self): ...


class OverloadTests(BaseTestCase):

    def test_overload_fails(self):
        with self.assertRaises(NotImplementedError):

            @overload
            def blah():
                pass

            blah()

    def test_overload_succeeds(self):
        @overload
        def blah():
            pass

        def blah():
            pass

        blah()

    @cpython_only  # gh-98713
    def test_overload_on_compiled_functions(self):
        with patch("typing._overload_registry",
                   defaultdict(lambda: defaultdict(dict))):
            # The registry starts out empty:
            self.assertEqual(typing._overload_registry, {})

            # This should just not fail:
            overload(sum)
            overload(print)

            # No overloads are recorded (but, it still has a side-effect):
            self.assertEqual(typing.get_overloads(sum), [])
            self.assertEqual(typing.get_overloads(print), [])

    def set_up_overloads(self):
        def blah():
            pass

        overload1 = blah
        overload(blah)

        def blah():
            pass

        overload2 = blah
        overload(blah)

        def blah():
            pass

        return blah, [overload1, overload2]

    # Make sure we don't clear the global overload registry
    @patch("typing._overload_registry",
        defaultdict(lambda: defaultdict(dict)))
    def test_overload_registry(self):
        # The registry starts out empty
        self.assertEqual(typing._overload_registry, {})

        impl, overloads = self.set_up_overloads()
        self.assertNotEqual(typing._overload_registry, {})
        self.assertEqual(list(get_overloads(impl)), overloads)

        def some_other_func(): pass
        overload(some_other_func)
        other_overload = some_other_func
        def some_other_func(): pass
        self.assertEqual(list(get_overloads(some_other_func)), [other_overload])
        # Unrelated function still has no overloads:
        def not_overloaded(): pass
        self.assertEqual(list(get_overloads(not_overloaded)), [])

        # Make sure that after we clear all overloads, the registry is
        # completely empty.
        clear_overloads()
        self.assertEqual(typing._overload_registry, {})
        self.assertEqual(get_overloads(impl), [])

        # Querying a function with no overloads shouldn't change the registry.
        def the_only_one(): pass
        self.assertEqual(get_overloads(the_only_one), [])
        self.assertEqual(typing._overload_registry, {})

    def test_overload_registry_repeated(self):
        for _ in range(2):
            impl, overloads = self.set_up_overloads()

            self.assertEqual(list(get_overloads(impl)), overloads)


from test.typinganndata import (
    ann_module, ann_module2, ann_module3, ann_module5, ann_module6,
)

T_a = TypeVar('T_a')

class AwaitableWrapper(typing.Awaitable[T_a]):

    def __init__(self, value):
        self.value = value

    def __await__(self) -> typing.Iterator[T_a]:
        yield
        return self.value

class AsyncIteratorWrapper(typing.AsyncIterator[T_a]):

    def __init__(self, value: typing.Iterable[T_a]):
        self.value = value

    def __aiter__(self) -> typing.AsyncIterator[T_a]:
        return self

    async def __anext__(self) -> T_a:
        data = await self.value
        if data:
            return data
        else:
            raise StopAsyncIteration

class ACM:
    async def __aenter__(self) -> int:
        return 42
    async def __aexit__(self, etype, eval, tb):
        return None

class A:
    y: float
class B(A):
    x: ClassVar[Optional['B']] = None
    y: int
    b: int
class CSub(B):
    z: ClassVar['CSub'] = B()
class G(Generic[T]):
    lst: ClassVar[List[T]] = []

class Loop:
    attr: Final['Loop']

class NoneAndForward:
    parent: 'NoneAndForward'
    meaning: None

class CoolEmployee(NamedTuple):
    name: str
    cool: int

class CoolEmployeeWithDefault(NamedTuple):
    name: str
    cool: int = 0

class XMeth(NamedTuple):
    x: int
    def double(self):
        return 2 * self.x

class XRepr(NamedTuple):
    x: int
    y: int = 1
    def __str__(self):
        return f'{self.x} -> {self.y}'
    def __add__(self, other):
        return 0

Label = TypedDict('Label', [('label', str)])

class Point2D(TypedDict):
    x: int
    y: int

class Point2DGeneric(Generic[T], TypedDict):
    a: T
    b: T

class Bar(_typed_dict_helper.Foo, total=False):
    b: int

class BarGeneric(_typed_dict_helper.FooGeneric[T], total=False):
    b: int

class LabelPoint2D(Point2D, Label): ...

class Options(TypedDict, total=False):
    log_level: int
    log_path: str

class TotalMovie(TypedDict):
    title: str
    year: NotRequired[int]

class NontotalMovie(TypedDict, total=False):
    title: Required[str]
    year: int

class ParentNontotalMovie(TypedDict, total=False):
    title: Required[str]

class ChildTotalMovie(ParentNontotalMovie):
    year: NotRequired[int]

class ParentDeeplyAnnotatedMovie(TypedDict):
    title: Annotated[Annotated[Required[str], "foobar"], "another level"]

class ChildDeeplyAnnotatedMovie(ParentDeeplyAnnotatedMovie):
    year: NotRequired[Annotated[int, 2000]]

class AnnotatedMovie(TypedDict):
    title: Annotated[Required[str], "foobar"]
    year: NotRequired[Annotated[int, 2000]]

class DeeplyAnnotatedMovie(TypedDict):
    title: Annotated[Annotated[Required[str], "foobar"], "another level"]
    year: NotRequired[Annotated[int, 2000]]

class WeirdlyQuotedMovie(TypedDict):
    title: Annotated['Annotated[Required[str], "foobar"]', "another level"]
    year: NotRequired['Annotated[int, 2000]']

class HasForeignBaseClass(mod_generics_cache.A):
    some_xrepr: 'XRepr'
    other_a: 'mod_generics_cache.A'

async def g_with(am: typing.AsyncContextManager[int]):
    x: int
    async with am as x:
        return x

try:
    g_with(ACM()).send(None)
except StopIteration as e:
    assert e.args[0] == 42

gth = get_type_hints

class ForRefExample:
    @ann_module.dec
    def func(self: 'ForRefExample'):
        pass

    @ann_module.dec
    @ann_module.dec
    def nested(self: 'ForRefExample'):
        pass


class GetTypeHintTests(BaseTestCase):
    def test_get_type_hints_from_various_objects(self):
        # For invalid objects should fail with TypeError (not AttributeError etc).
        with self.assertRaises(TypeError):
            gth(123)
        with self.assertRaises(TypeError):
            gth('abc')
        with self.assertRaises(TypeError):
            gth(None)

    def test_get_type_hints_modules(self):
        ann_module_type_hints = {'f': Tuple[int, int], 'x': int, 'y': str, 'u': int | float}
        self.assertEqual(gth(ann_module), ann_module_type_hints)
        self.assertEqual(gth(ann_module2), {})
        self.assertEqual(gth(ann_module3), {})

    @skip("known bug")
    def test_get_type_hints_modules_forwardref(self):
        # FIXME: This currently exposes a bug in typing. Cached forward references
        # don't account for the case where there are multiple types of the same
        # name coming from different modules in the same program.
        mgc_hints = {'default_a': Optional[mod_generics_cache.A],
                     'default_b': Optional[mod_generics_cache.B]}
        self.assertEqual(gth(mod_generics_cache), mgc_hints)

    def test_get_type_hints_classes(self):
        self.assertEqual(gth(ann_module.C),  # gth will find the right globalns
                         {'y': Optional[ann_module.C]})
        self.assertIsInstance(gth(ann_module.j_class), dict)
        self.assertEqual(gth(ann_module.M), {'o': type})
        self.assertEqual(gth(ann_module.D),
                         {'j': str, 'k': str, 'y': Optional[ann_module.C]})
        self.assertEqual(gth(ann_module.Y), {'z': int})
        self.assertEqual(gth(ann_module.h_class),
                         {'y': Optional[ann_module.C]})
        self.assertEqual(gth(ann_module.S), {'x': str, 'y': str})
        self.assertEqual(gth(ann_module.foo), {'x': int})
        self.assertEqual(gth(NoneAndForward),
                         {'parent': NoneAndForward, 'meaning': type(None)})
        self.assertEqual(gth(HasForeignBaseClass),
                         {'some_xrepr': XRepr, 'other_a': mod_generics_cache.A,
                          'some_b': mod_generics_cache.B})
        self.assertEqual(gth(XRepr.__new__),
                         {'x': int, 'y': int})
        self.assertEqual(gth(mod_generics_cache.B),
                         {'my_inner_a1': mod_generics_cache.B.A,
                          'my_inner_a2': mod_generics_cache.B.A,
                          'my_outer_a': mod_generics_cache.A})

    def test_get_type_hints_classes_no_implicit_optional(self):
        class WithNoneDefault:
            field: int = None  # most type-checkers won't be happy with it

        self.assertEqual(gth(WithNoneDefault), {'field': int})

    def test_respect_no_type_check(self):
        @no_type_check
        class NoTpCheck:
            class Inn:
                def __init__(self, x: 'not a type'): ...
        self.assertTrue(NoTpCheck.__no_type_check__)
        self.assertTrue(NoTpCheck.Inn.__init__.__no_type_check__)
        self.assertEqual(gth(ann_module2.NTC.meth), {})
        class ABase(Generic[T]):
            def meth(x: int): ...
        @no_type_check
        class Der(ABase): ...
        self.assertEqual(gth(ABase.meth), {'x': int})

    def test_get_type_hints_for_builtins(self):
        # Should not fail for built-in classes and functions.
        self.assertEqual(gth(int), {})
        self.assertEqual(gth(type), {})
        self.assertEqual(gth(dir), {})
        self.assertEqual(gth(len), {})
        self.assertEqual(gth(object.__str__), {})
        self.assertEqual(gth(object().__str__), {})
        self.assertEqual(gth(str.join), {})

    def test_previous_behavior(self):
        def testf(x, y): ...
        testf.__annotations__['x'] = 'int'
        self.assertEqual(gth(testf), {'x': int})
        def testg(x: None): ...
        self.assertEqual(gth(testg), {'x': type(None)})

    def test_get_type_hints_for_object_with_annotations(self):
        class A: ...
        class B: ...
        b = B()
        b.__annotations__ = {'x': 'A'}
        self.assertEqual(gth(b, locals()), {'x': A})

    def test_get_type_hints_ClassVar(self):
        self.assertEqual(gth(ann_module2.CV, ann_module2.__dict__),
                         {'var': typing.ClassVar[ann_module2.CV]})
        self.assertEqual(gth(B, globals()),
                         {'y': int, 'x': ClassVar[Optional[B]], 'b': int})
        self.assertEqual(gth(CSub, globals()),
                         {'z': ClassVar[CSub], 'y': int, 'b': int,
                          'x': ClassVar[Optional[B]]})
        self.assertEqual(gth(G), {'lst': ClassVar[List[T]]})

    def test_get_type_hints_wrapped_decoratored_func(self):
        expects = {'self': ForRefExample}
        self.assertEqual(gth(ForRefExample.func), expects)
        self.assertEqual(gth(ForRefExample.nested), expects)

    def test_get_type_hints_annotated(self):
        def foobar(x: List['X']): ...
        X = Annotated[int, (1, 10)]
        self.assertEqual(
            get_type_hints(foobar, globals(), locals()),
            {'x': List[int]}
        )
        self.assertEqual(
            get_type_hints(foobar, globals(), locals(), include_extras=True),
            {'x': List[Annotated[int, (1, 10)]]}
        )

        def foobar(x: list[ForwardRef('X')]): ...
        X = Annotated[int, (1, 10)]
        self.assertEqual(
            get_type_hints(foobar, globals(), locals()),
            {'x': list[int]}
        )
        self.assertEqual(
            get_type_hints(foobar, globals(), locals(), include_extras=True),
            {'x': list[Annotated[int, (1, 10)]]}
        )

        BA = Tuple[Annotated[T, (1, 0)], ...]
        def barfoo(x: BA): ...
        self.assertEqual(get_type_hints(barfoo, globals(), locals())['x'], Tuple[T, ...])
        self.assertEqual(
            get_type_hints(barfoo, globals(), locals(), include_extras=True)['x'],
            BA
        )

        BA = tuple[Annotated[T, (1, 0)], ...]
        def barfoo(x: BA): ...
        self.assertEqual(get_type_hints(barfoo, globals(), locals())['x'], tuple[T, ...])
        self.assertEqual(
            get_type_hints(barfoo, globals(), locals(), include_extras=True)['x'],
            BA
        )

        def barfoo2(x: typing.Callable[..., Annotated[List[T], "const"]],
                    y: typing.Union[int, Annotated[T, "mutable"]]): ...
        self.assertEqual(
            get_type_hints(barfoo2, globals(), locals()),
            {'x': typing.Callable[..., List[T]], 'y': typing.Union[int, T]}
        )

        BA2 = typing.Callable[..., List[T]]
        def barfoo3(x: BA2): ...
        self.assertIs(
            get_type_hints(barfoo3, globals(), locals(), include_extras=True)["x"],
            BA2
        )
        BA3 = typing.Annotated[int | float, "const"]
        def barfoo4(x: BA3): ...
        self.assertEqual(
            get_type_hints(barfoo4, globals(), locals()),
            {"x": int | float}
        )
        self.assertEqual(
            get_type_hints(barfoo4, globals(), locals(), include_extras=True),
            {"x": typing.Annotated[int | float, "const"]}
        )

    def test_get_type_hints_annotated_in_union(self):  # bpo-46603
        def with_union(x: int | list[Annotated[str, 'meta']]): ...

        self.assertEqual(get_type_hints(with_union), {'x': int | list[str]})
        self.assertEqual(
            get_type_hints(with_union, include_extras=True),
            {'x': int | list[Annotated[str, 'meta']]},
        )

    def test_get_type_hints_annotated_refs(self):

        Const = Annotated[T, "Const"]

        class MySet(Generic[T]):

            def __ior__(self, other: "Const[MySet[T]]") -> "MySet[T]":
                ...

            def __iand__(self, other: Const["MySet[T]"]) -> "MySet[T]":
                ...

        self.assertEqual(
            get_type_hints(MySet.__iand__, globals(), locals()),
            {'other': MySet[T], 'return': MySet[T]}
        )

        self.assertEqual(
            get_type_hints(MySet.__iand__, globals(), locals(), include_extras=True),
            {'other': Const[MySet[T]], 'return': MySet[T]}
        )

        self.assertEqual(
            get_type_hints(MySet.__ior__, globals(), locals()),
            {'other': MySet[T], 'return': MySet[T]}
        )

    def test_get_type_hints_annotated_with_none_default(self):
        # See: https://bugs.python.org/issue46195
        def annotated_with_none_default(x: Annotated[int, 'data'] = None): ...
        self.assertEqual(
            get_type_hints(annotated_with_none_default),
            {'x': int},
        )
        self.assertEqual(
            get_type_hints(annotated_with_none_default, include_extras=True),
            {'x': Annotated[int, 'data']},
        )

    def test_get_type_hints_classes_str_annotations(self):
        class Foo:
            y = str
            x: 'y'
        # This previously raised an error under PEP 563.
        self.assertEqual(get_type_hints(Foo), {'x': str})

    def test_get_type_hints_bad_module(self):
        # bpo-41515
        class BadModule:
            pass
        BadModule.__module__ = 'bad' # Something not in sys.modules
        self.assertNotIn('bad', sys.modules)
        self.assertEqual(get_type_hints(BadModule), {})

    def test_get_type_hints_annotated_bad_module(self):
        # See https://bugs.python.org/issue44468
        class BadBase:
            foo: tuple
        class BadType(BadBase):
            bar: list
        BadType.__module__ = BadBase.__module__ = 'bad'
        self.assertNotIn('bad', sys.modules)
        self.assertEqual(get_type_hints(BadType), {'foo': tuple, 'bar': list})

    def test_forward_ref_and_final(self):
        # https://bugs.python.org/issue45166
        hints = get_type_hints(ann_module5)
        self.assertEqual(hints, {'name': Final[str]})

        hints = get_type_hints(ann_module5.MyClass)
        self.assertEqual(hints, {'value': Final})

    def test_top_level_class_var(self):
        # https://bugs.python.org/issue45166
        with self.assertRaisesRegex(
            TypeError,
            r'typing.ClassVar\[int\] is not valid as type argument',
        ):
            get_type_hints(ann_module6)

    def test_get_type_hints_typeddict(self):
        self.assertEqual(get_type_hints(TotalMovie), {'title': str, 'year': int})
        self.assertEqual(get_type_hints(TotalMovie, include_extras=True), {
            'title': str,
            'year': NotRequired[int],
        })

        self.assertEqual(get_type_hints(AnnotatedMovie), {'title': str, 'year': int})
        self.assertEqual(get_type_hints(AnnotatedMovie, include_extras=True), {
            'title': Annotated[Required[str], "foobar"],
            'year': NotRequired[Annotated[int, 2000]],
        })

        self.assertEqual(get_type_hints(DeeplyAnnotatedMovie), {'title': str, 'year': int})
        self.assertEqual(get_type_hints(DeeplyAnnotatedMovie, include_extras=True), {
            'title': Annotated[Required[str], "foobar", "another level"],
            'year': NotRequired[Annotated[int, 2000]],
        })

        self.assertEqual(get_type_hints(WeirdlyQuotedMovie), {'title': str, 'year': int})
        self.assertEqual(get_type_hints(WeirdlyQuotedMovie, include_extras=True), {
            'title': Annotated[Required[str], "foobar", "another level"],
            'year': NotRequired[Annotated[int, 2000]],
        })

        self.assertEqual(get_type_hints(_typed_dict_helper.VeryAnnotated), {'a': int})
        self.assertEqual(get_type_hints(_typed_dict_helper.VeryAnnotated, include_extras=True), {
            'a': Annotated[Required[int], "a", "b", "c"]
        })

        self.assertEqual(get_type_hints(ChildTotalMovie), {"title": str, "year": int})
        self.assertEqual(get_type_hints(ChildTotalMovie, include_extras=True), {
            "title": Required[str], "year": NotRequired[int]
        })

        self.assertEqual(get_type_hints(ChildDeeplyAnnotatedMovie), {"title": str, "year": int})
        self.assertEqual(get_type_hints(ChildDeeplyAnnotatedMovie, include_extras=True), {
            "title": Annotated[Required[str], "foobar", "another level"],
            "year": NotRequired[Annotated[int, 2000]]
        })

    def test_get_type_hints_collections_abc_callable(self):
        # https://github.com/python/cpython/issues/91621
        P = ParamSpec('P')
        def f(x: collections.abc.Callable[[int], int]): ...
        def g(x: collections.abc.Callable[..., int]): ...
        def h(x: collections.abc.Callable[P, int]): ...

        self.assertEqual(get_type_hints(f), {'x': collections.abc.Callable[[int], int]})
        self.assertEqual(get_type_hints(g), {'x': collections.abc.Callable[..., int]})
        self.assertEqual(get_type_hints(h), {'x': collections.abc.Callable[P, int]})


class GetUtilitiesTestCase(TestCase):
    def test_get_origin(self):
        T = TypeVar('T')
        Ts = TypeVarTuple('Ts')
        P = ParamSpec('P')
        class C(Generic[T]): pass
        self.assertIs(get_origin(C[int]), C)
        self.assertIs(get_origin(C[T]), C)
        self.assertIs(get_origin(int), None)
        self.assertIs(get_origin(ClassVar[int]), ClassVar)
        self.assertIs(get_origin(Union[int, str]), Union)
        self.assertIs(get_origin(Literal[42, 43]), Literal)
        self.assertIs(get_origin(Final[List[int]]), Final)
        self.assertIs(get_origin(Generic), Generic)
        self.assertIs(get_origin(Generic[T]), Generic)
        self.assertIs(get_origin(List[Tuple[T, T]][int]), list)
        self.assertIs(get_origin(Annotated[T, 'thing']), Annotated)
        self.assertIs(get_origin(List), list)
        self.assertIs(get_origin(Tuple), tuple)
        self.assertIs(get_origin(Callable), collections.abc.Callable)
        self.assertIs(get_origin(list[int]), list)
        self.assertIs(get_origin(list), None)
        self.assertIs(get_origin(list | str), types.UnionType)
        self.assertIs(get_origin(P.args), P)
        self.assertIs(get_origin(P.kwargs), P)
        self.assertIs(get_origin(Required[int]), Required)
        self.assertIs(get_origin(NotRequired[int]), NotRequired)
        self.assertIs(get_origin((*Ts,)[0]), Unpack)
        self.assertIs(get_origin(Unpack[Ts]), Unpack)
        self.assertIs(get_origin((*tuple[*Ts],)[0]), tuple)
        self.assertIs(get_origin(Unpack[Tuple[Unpack[Ts]]]), Unpack)

    def test_get_args(self):
        T = TypeVar('T')
        class C(Generic[T]): pass
        self.assertEqual(get_args(C[int]), (int,))
        self.assertEqual(get_args(C[T]), (T,))
        self.assertEqual(get_args(typing.SupportsAbs[int]), (int,))  # Protocol
        self.assertEqual(get_args(typing.SupportsAbs[T]), (T,))
        self.assertEqual(get_args(Point2DGeneric[int]), (int,))  # TypedDict
        self.assertEqual(get_args(Point2DGeneric[T]), (T,))
        self.assertEqual(get_args(T), ())
        self.assertEqual(get_args(int), ())
        self.assertEqual(get_args(Any), ())
        self.assertEqual(get_args(Self), ())
        self.assertEqual(get_args(LiteralString), ())
        self.assertEqual(get_args(ClassVar[int]), (int,))
        self.assertEqual(get_args(Union[int, str]), (int, str))
        self.assertEqual(get_args(Literal[42, 43]), (42, 43))
        self.assertEqual(get_args(Final[List[int]]), (List[int],))
        self.assertEqual(get_args(Optional[int]), (int, type(None)))
        self.assertEqual(get_args(Union[int, None]), (int, type(None)))
        self.assertEqual(get_args(Union[int, Tuple[T, int]][str]),
                         (int, Tuple[str, int]))
        self.assertEqual(get_args(typing.Dict[int, Tuple[T, T]][Optional[int]]),
                         (int, Tuple[Optional[int], Optional[int]]))
        self.assertEqual(get_args(Callable[[], T][int]), ([], int))
        self.assertEqual(get_args(Callable[..., int]), (..., int))
        self.assertEqual(get_args(Callable[[int], str]), ([int], str))
        self.assertEqual(get_args(Union[int, Callable[[Tuple[T, ...]], str]]),
                         (int, Callable[[Tuple[T, ...]], str]))
        self.assertEqual(get_args(Tuple[int, ...]), (int, ...))
        self.assertEqual(get_args(Tuple[()]), ())
        self.assertEqual(get_args(Annotated[T, 'one', 2, ['three']]), (T, 'one', 2, ['three']))
        self.assertEqual(get_args(List), ())
        self.assertEqual(get_args(Tuple), ())
        self.assertEqual(get_args(Callable), ())
        self.assertEqual(get_args(list[int]), (int,))
        self.assertEqual(get_args(list), ())
        self.assertEqual(get_args(collections.abc.Callable[[int], str]), ([int], str))
        self.assertEqual(get_args(collections.abc.Callable[..., str]), (..., str))
        self.assertEqual(get_args(collections.abc.Callable[[], str]), ([], str))
        self.assertEqual(get_args(collections.abc.Callable[[int], str]),
                         get_args(Callable[[int], str]))
        P = ParamSpec('P')
        self.assertEqual(get_args(P), ())
        self.assertEqual(get_args(P.args), ())
        self.assertEqual(get_args(P.kwargs), ())
        self.assertEqual(get_args(Callable[P, int]), (P, int))
        self.assertEqual(get_args(collections.abc.Callable[P, int]), (P, int))
        self.assertEqual(get_args(Callable[Concatenate[int, P], int]),
                         (Concatenate[int, P], int))
        self.assertEqual(get_args(collections.abc.Callable[Concatenate[int, P], int]),
                         (Concatenate[int, P], int))
        self.assertEqual(get_args(Concatenate[int, str, P]), (int, str, P))
        self.assertEqual(get_args(list | str), (list, str))
        self.assertEqual(get_args(Required[int]), (int,))
        self.assertEqual(get_args(NotRequired[int]), (int,))
        self.assertEqual(get_args(TypeAlias), ())
        self.assertEqual(get_args(TypeGuard[int]), (int,))
        self.assertEqual(get_args(TypeIs[range]), (range,))
        Ts = TypeVarTuple('Ts')
        self.assertEqual(get_args(Ts), ())
        self.assertEqual(get_args((*Ts,)[0]), (Ts,))
        self.assertEqual(get_args(Unpack[Ts]), (Ts,))
        self.assertEqual(get_args(tuple[*Ts]), (*Ts,))
        self.assertEqual(get_args(tuple[Unpack[Ts]]), (Unpack[Ts],))
        self.assertEqual(get_args((*tuple[*Ts],)[0]), (*Ts,))
        self.assertEqual(get_args(Unpack[tuple[Unpack[Ts]]]), (tuple[Unpack[Ts]],))


class CollectionsAbcTests(BaseTestCase):

    def test_hashable(self):
        self.assertIsInstance(42, typing.Hashable)
        self.assertNotIsInstance([], typing.Hashable)

    def test_iterable(self):
        self.assertIsInstance([], typing.Iterable)
        # Due to ABC caching, the second time takes a separate code
        # path and could fail.  So call this a few times.
        self.assertIsInstance([], typing.Iterable)
        self.assertIsInstance([], typing.Iterable)
        self.assertNotIsInstance(42, typing.Iterable)
        # Just in case, also test issubclass() a few times.
        self.assertIsSubclass(list, typing.Iterable)
        self.assertIsSubclass(list, typing.Iterable)

    def test_iterator(self):
        it = iter([])
        self.assertIsInstance(it, typing.Iterator)
        self.assertNotIsInstance(42, typing.Iterator)

    def test_awaitable(self):
        async def foo() -> typing.Awaitable[int]:
            return await AwaitableWrapper(42)
        g = foo()
        self.assertIsInstance(g, typing.Awaitable)
        self.assertNotIsInstance(foo, typing.Awaitable)
        g.send(None)  # Run foo() till completion, to avoid warning.

    def test_coroutine(self):
        async def foo():
            return
        g = foo()
        self.assertIsInstance(g, typing.Coroutine)
        with self.assertRaises(TypeError):
            isinstance(g, typing.Coroutine[int])
        self.assertNotIsInstance(foo, typing.Coroutine)
        try:
            g.send(None)
        except StopIteration:
            pass

    def test_async_iterable(self):
        base_it = range(10)  # type: Iterator[int]
        it = AsyncIteratorWrapper(base_it)
        self.assertIsInstance(it, typing.AsyncIterable)
        self.assertIsInstance(it, typing.AsyncIterable)
        self.assertNotIsInstance(42, typing.AsyncIterable)

    def test_async_iterator(self):
        base_it = range(10)  # type: Iterator[int]
        it = AsyncIteratorWrapper(base_it)
        self.assertIsInstance(it, typing.AsyncIterator)
        self.assertNotIsInstance(42, typing.AsyncIterator)

    def test_sized(self):
        self.assertIsInstance([], typing.Sized)
        self.assertNotIsInstance(42, typing.Sized)

    def test_container(self):
        self.assertIsInstance([], typing.Container)
        self.assertNotIsInstance(42, typing.Container)

    def test_collection(self):
        self.assertIsInstance(tuple(), typing.Collection)
        self.assertIsInstance(frozenset(), typing.Collection)
        self.assertIsSubclass(dict, typing.Collection)
        self.assertNotIsInstance(42, typing.Collection)

    def test_abstractset(self):
        self.assertIsInstance(set(), typing.AbstractSet)
        self.assertNotIsInstance(42, typing.AbstractSet)

    def test_mutableset(self):
        self.assertIsInstance(set(), typing.MutableSet)
        self.assertNotIsInstance(frozenset(), typing.MutableSet)

    def test_mapping(self):
        self.assertIsInstance({}, typing.Mapping)
        self.assertNotIsInstance(42, typing.Mapping)

    def test_mutablemapping(self):
        self.assertIsInstance({}, typing.MutableMapping)
        self.assertNotIsInstance(42, typing.MutableMapping)

    def test_sequence(self):
        self.assertIsInstance([], typing.Sequence)
        self.assertNotIsInstance(42, typing.Sequence)

    def test_mutablesequence(self):
        self.assertIsInstance([], typing.MutableSequence)
        self.assertNotIsInstance((), typing.MutableSequence)

    def test_list(self):
        self.assertIsSubclass(list, typing.List)

    def test_deque(self):
        self.assertIsSubclass(collections.deque, typing.Deque)
        class MyDeque(typing.Deque[int]): ...
        self.assertIsInstance(MyDeque(), collections.deque)

    def test_counter(self):
        self.assertIsSubclass(collections.Counter, typing.Counter)

    def test_set(self):
        self.assertIsSubclass(set, typing.Set)
        self.assertNotIsSubclass(frozenset, typing.Set)

    def test_frozenset(self):
        self.assertIsSubclass(frozenset, typing.FrozenSet)
        self.assertNotIsSubclass(set, typing.FrozenSet)

    def test_dict(self):
        self.assertIsSubclass(dict, typing.Dict)

    def test_dict_subscribe(self):
        K = TypeVar('K')
        V = TypeVar('V')
        self.assertEqual(Dict[K, V][str, int], Dict[str, int])
        self.assertEqual(Dict[K, int][str], Dict[str, int])
        self.assertEqual(Dict[str, V][int], Dict[str, int])
        self.assertEqual(Dict[K, List[V]][str, int], Dict[str, List[int]])
        self.assertEqual(Dict[K, List[int]][str], Dict[str, List[int]])
        self.assertEqual(Dict[K, list[V]][str, int], Dict[str, list[int]])
        self.assertEqual(Dict[K, list[int]][str], Dict[str, list[int]])

    def test_no_list_instantiation(self):
        with self.assertRaises(TypeError):
            typing.List()
        with self.assertRaises(TypeError):
            typing.List[T]()
        with self.assertRaises(TypeError):
            typing.List[int]()

    def test_list_subclass(self):

        class MyList(typing.List[int]):
            pass

        a = MyList()
        self.assertIsInstance(a, MyList)
        self.assertIsInstance(a, typing.Sequence)

        self.assertIsSubclass(MyList, list)
        self.assertNotIsSubclass(list, MyList)

    def test_no_dict_instantiation(self):
        with self.assertRaises(TypeError):
            typing.Dict()
        with self.assertRaises(TypeError):
            typing.Dict[KT, VT]()
        with self.assertRaises(TypeError):
            typing.Dict[str, int]()

    def test_dict_subclass(self):

        class MyDict(typing.Dict[str, int]):
            pass

        d = MyDict()
        self.assertIsInstance(d, MyDict)
        self.assertIsInstance(d, typing.MutableMapping)

        self.assertIsSubclass(MyDict, dict)
        self.assertNotIsSubclass(dict, MyDict)

    def test_defaultdict_instantiation(self):
        self.assertIs(type(typing.DefaultDict()), collections.defaultdict)
        self.assertIs(type(typing.DefaultDict[KT, VT]()), collections.defaultdict)
        self.assertIs(type(typing.DefaultDict[str, int]()), collections.defaultdict)

    def test_defaultdict_subclass(self):

        class MyDefDict(typing.DefaultDict[str, int]):
            pass

        dd = MyDefDict()
        self.assertIsInstance(dd, MyDefDict)

        self.assertIsSubclass(MyDefDict, collections.defaultdict)
        self.assertNotIsSubclass(collections.defaultdict, MyDefDict)

    def test_ordereddict_instantiation(self):
        self.assertIs(type(typing.OrderedDict()), collections.OrderedDict)
        self.assertIs(type(typing.OrderedDict[KT, VT]()), collections.OrderedDict)
        self.assertIs(type(typing.OrderedDict[str, int]()), collections.OrderedDict)

    def test_ordereddict_subclass(self):

        class MyOrdDict(typing.OrderedDict[str, int]):
            pass

        od = MyOrdDict()
        self.assertIsInstance(od, MyOrdDict)

        self.assertIsSubclass(MyOrdDict, collections.OrderedDict)
        self.assertNotIsSubclass(collections.OrderedDict, MyOrdDict)

    def test_chainmap_instantiation(self):
        self.assertIs(type(typing.ChainMap()), collections.ChainMap)
        self.assertIs(type(typing.ChainMap[KT, VT]()), collections.ChainMap)
        self.assertIs(type(typing.ChainMap[str, int]()), collections.ChainMap)
        class CM(typing.ChainMap[KT, VT]): ...
        self.assertIs(type(CM[int, str]()), CM)

    def test_chainmap_subclass(self):

        class MyChainMap(typing.ChainMap[str, int]):
            pass

        cm = MyChainMap()
        self.assertIsInstance(cm, MyChainMap)

        self.assertIsSubclass(MyChainMap, collections.ChainMap)
        self.assertNotIsSubclass(collections.ChainMap, MyChainMap)

    def test_deque_instantiation(self):
        self.assertIs(type(typing.Deque()), collections.deque)
        self.assertIs(type(typing.Deque[T]()), collections.deque)
        self.assertIs(type(typing.Deque[int]()), collections.deque)
        class D(typing.Deque[T]): ...
        self.assertIs(type(D[int]()), D)

    def test_counter_instantiation(self):
        self.assertIs(type(typing.Counter()), collections.Counter)
        self.assertIs(type(typing.Counter[T]()), collections.Counter)
        self.assertIs(type(typing.Counter[int]()), collections.Counter)
        class C(typing.Counter[T]): ...
        self.assertIs(type(C[int]()), C)

    def test_counter_subclass_instantiation(self):

        class MyCounter(typing.Counter[int]):
            pass

        d = MyCounter()
        self.assertIsInstance(d, MyCounter)
        self.assertIsInstance(d, typing.Counter)
        self.assertIsInstance(d, collections.Counter)

    def test_no_set_instantiation(self):
        with self.assertRaises(TypeError):
            typing.Set()
        with self.assertRaises(TypeError):
            typing.Set[T]()
        with self.assertRaises(TypeError):
            typing.Set[int]()

    def test_set_subclass_instantiation(self):

        class MySet(typing.Set[int]):
            pass

        d = MySet()
        self.assertIsInstance(d, MySet)

    def test_no_frozenset_instantiation(self):
        with self.assertRaises(TypeError):
            typing.FrozenSet()
        with self.assertRaises(TypeError):
            typing.FrozenSet[T]()
        with self.assertRaises(TypeError):
            typing.FrozenSet[int]()

    def test_frozenset_subclass_instantiation(self):

        class MyFrozenSet(typing.FrozenSet[int]):
            pass

        d = MyFrozenSet()
        self.assertIsInstance(d, MyFrozenSet)

    def test_no_tuple_instantiation(self):
        with self.assertRaises(TypeError):
            Tuple()
        with self.assertRaises(TypeError):
            Tuple[T]()
        with self.assertRaises(TypeError):
            Tuple[int]()

    def test_generator(self):
        def foo():
            yield 42
        g = foo()
        self.assertIsSubclass(type(g), typing.Generator)

    def test_generator_default(self):
        g1 = typing.Generator[int]
        g2 = typing.Generator[int, None, None]
        self.assertEqual(get_args(g1), (int, type(None), type(None)))
        self.assertEqual(get_args(g1), get_args(g2))

        g3 = typing.Generator[int, float]
        g4 = typing.Generator[int, float, None]
        self.assertEqual(get_args(g3), (int, float, type(None)))
        self.assertEqual(get_args(g3), get_args(g4))

    def test_no_generator_instantiation(self):
        with self.assertRaises(TypeError):
            typing.Generator()
        with self.assertRaises(TypeError):
            typing.Generator[T, T, T]()
        with self.assertRaises(TypeError):
            typing.Generator[int, int, int]()

    def test_async_generator(self):
        async def f():
             yield 42
        g = f()
        self.assertIsSubclass(type(g), typing.AsyncGenerator)

    def test_no_async_generator_instantiation(self):
        with self.assertRaises(TypeError):
            typing.AsyncGenerator()
        with self.assertRaises(TypeError):
            typing.AsyncGenerator[T, T]()
        with self.assertRaises(TypeError):
            typing.AsyncGenerator[int, int]()

    def test_subclassing(self):

        class MMA(typing.MutableMapping):
            pass

        with self.assertRaises(TypeError):  # It's abstract
            MMA()

        class MMC(MMA):
            def __getitem__(self, k):
                return None
            def __setitem__(self, k, v):
                pass
            def __delitem__(self, k):
                pass
            def __iter__(self):
                return iter(())
            def __len__(self):
                return 0

        self.assertEqual(len(MMC()), 0)
        self.assertTrue(callable(MMC.update))
        self.assertIsInstance(MMC(), typing.Mapping)

        class MMB(typing.MutableMapping[KT, VT]):
            def __getitem__(self, k):
                return None
            def __setitem__(self, k, v):
                pass
            def __delitem__(self, k):
                pass
            def __iter__(self):
                return iter(())
            def __len__(self):
                return 0

        self.assertEqual(len(MMB()), 0)
        self.assertEqual(len(MMB[str, str]()), 0)
        self.assertEqual(len(MMB[KT, VT]()), 0)

        self.assertNotIsSubclass(dict, MMA)
        self.assertNotIsSubclass(dict, MMB)

        self.assertIsSubclass(MMA, typing.Mapping)
        self.assertIsSubclass(MMB, typing.Mapping)
        self.assertIsSubclass(MMC, typing.Mapping)

        self.assertIsInstance(MMB[KT, VT](), typing.Mapping)
        self.assertIsInstance(MMB[KT, VT](), collections.abc.Mapping)

        self.assertIsSubclass(MMA, collections.abc.Mapping)
        self.assertIsSubclass(MMB, collections.abc.Mapping)
        self.assertIsSubclass(MMC, collections.abc.Mapping)

        with self.assertRaises(TypeError):
            issubclass(MMB[str, str], typing.Mapping)
        self.assertIsSubclass(MMC, MMA)

        class I(typing.Iterable): ...
        self.assertNotIsSubclass(list, I)

        class G(typing.Generator[int, int, int]): ...
        def g(): yield 0
        self.assertIsSubclass(G, typing.Generator)
        self.assertIsSubclass(G, typing.Iterable)
        self.assertIsSubclass(G, collections.abc.Generator)
        self.assertIsSubclass(G, collections.abc.Iterable)
        self.assertNotIsSubclass(type(g), G)

    def test_subclassing_async_generator(self):
        class G(typing.AsyncGenerator[int, int]):
            def asend(self, value):
                pass
            def athrow(self, typ, val=None, tb=None):
                pass

        async def g(): yield 0

        self.assertIsSubclass(G, typing.AsyncGenerator)
        self.assertIsSubclass(G, typing.AsyncIterable)
        self.assertIsSubclass(G, collections.abc.AsyncGenerator)
        self.assertIsSubclass(G, collections.abc.AsyncIterable)
        self.assertNotIsSubclass(type(g), G)

        instance = G()
        self.assertIsInstance(instance, typing.AsyncGenerator)
        self.assertIsInstance(instance, typing.AsyncIterable)
        self.assertIsInstance(instance, collections.abc.AsyncGenerator)
        self.assertIsInstance(instance, collections.abc.AsyncIterable)
        self.assertNotIsInstance(type(g), G)
        self.assertNotIsInstance(g, G)

    def test_subclassing_subclasshook(self):

        class Base(typing.Iterable):
            @classmethod
            def __subclasshook__(cls, other):
                if other.__name__ == 'Foo':
                    return True
                else:
                    return False

        class C(Base): ...
        class Foo: ...
        class Bar: ...
        self.assertIsSubclass(Foo, Base)
        self.assertIsSubclass(Foo, C)
        self.assertNotIsSubclass(Bar, C)

    def test_subclassing_register(self):

        class A(typing.Container): ...
        class B(A): ...

        class C: ...
        A.register(C)
        self.assertIsSubclass(C, A)
        self.assertNotIsSubclass(C, B)

        class D: ...
        B.register(D)
        self.assertIsSubclass(D, A)
        self.assertIsSubclass(D, B)

        class M(): ...
        collections.abc.MutableMapping.register(M)
        self.assertIsSubclass(M, typing.Mapping)

    def test_collections_as_base(self):

        class M(collections.abc.Mapping): ...
        self.assertIsSubclass(M, typing.Mapping)
        self.assertIsSubclass(M, typing.Iterable)

        class S(collections.abc.MutableSequence): ...
        self.assertIsSubclass(S, typing.MutableSequence)
        self.assertIsSubclass(S, typing.Iterable)

        class I(collections.abc.Iterable): ...
        self.assertIsSubclass(I, typing.Iterable)

        class A(collections.abc.Mapping, metaclass=abc.ABCMeta): ...
        class B: ...
        A.register(B)
        self.assertIsSubclass(B, typing.Mapping)

    def test_or_and_ror(self):
        self.assertEqual(typing.Sized | typing.Awaitable, Union[typing.Sized, typing.Awaitable])
        self.assertEqual(typing.Coroutine | typing.Hashable, Union[typing.Coroutine, typing.Hashable])


class OtherABCTests(BaseTestCase):

    def test_contextmanager(self):
        @contextlib.contextmanager
        def manager():
            yield 42

        cm = manager()
        self.assertIsInstance(cm, typing.ContextManager)
        self.assertNotIsInstance(42, typing.ContextManager)

    def test_contextmanager_type_params(self):
        cm1 = typing.ContextManager[int]
        self.assertEqual(get_args(cm1), (int, bool | None))
        cm2 = typing.ContextManager[int, None]
        self.assertEqual(get_args(cm2), (int, types.NoneType))

        type gen_cm[T1, T2] = typing.ContextManager[T1, T2]
        self.assertEqual(get_args(gen_cm.__value__[int, None]), (int, types.NoneType))

    def test_async_contextmanager(self):
        class NotACM:
            pass
        self.assertIsInstance(ACM(), typing.AsyncContextManager)
        self.assertNotIsInstance(NotACM(), typing.AsyncContextManager)
        @contextlib.contextmanager
        def manager():
            yield 42

        cm = manager()
        self.assertNotIsInstance(cm, typing.AsyncContextManager)
        self.assertEqual(typing.AsyncContextManager[int].__args__, (int, bool | None))
        with self.assertRaises(TypeError):
            isinstance(42, typing.AsyncContextManager[int])
        with self.assertRaises(TypeError):
            typing.AsyncContextManager[int, str, float]

    def test_asynccontextmanager_type_params(self):
        cm1 = typing.AsyncContextManager[int]
        self.assertEqual(get_args(cm1), (int, bool | None))
        cm2 = typing.AsyncContextManager[int, None]
        self.assertEqual(get_args(cm2), (int, types.NoneType))


class TypeTests(BaseTestCase):

    def test_type_basic(self):

        class User: pass
        class BasicUser(User): pass
        class ProUser(User): pass

        def new_user(user_class: Type[User]) -> User:
            return user_class()

        new_user(BasicUser)

    def test_type_typevar(self):

        class User: pass
        class BasicUser(User): pass
        class ProUser(User): pass

        U = TypeVar('U', bound=User)

        def new_user(user_class: Type[U]) -> U:
            return user_class()

        new_user(BasicUser)

    def test_type_optional(self):
        A = Optional[Type[BaseException]]

        def foo(a: A) -> Optional[BaseException]:
            if a is None:
                return None
            else:
                return a()

        self.assertIsInstance(foo(KeyboardInterrupt), KeyboardInterrupt)
        self.assertIsNone(foo(None))


class TestModules(TestCase):
    func_names = ['_idfunc']

    def test_c_functions(self):
        for fname in self.func_names:
            self.assertEqual(getattr(typing, fname).__module__, '_typing')


class NewTypeTests(BaseTestCase):
    @classmethod
    def setUpClass(cls):
        global UserId
        UserId = typing.NewType('UserId', int)
        cls.UserName = typing.NewType(cls.__qualname__ + '.UserName', str)

    @classmethod
    def tearDownClass(cls):
        global UserId
        del UserId
        del cls.UserName

    def test_basic(self):
        self.assertIsInstance(UserId(5), int)
        self.assertIsInstance(self.UserName('Joe'), str)
        self.assertEqual(UserId(5) + 1, 6)

    def test_errors(self):
        with self.assertRaises(TypeError):
            issubclass(UserId, int)
        with self.assertRaises(TypeError):
            class D(UserId):
                pass

    def test_or(self):
        for cls in (int, self.UserName):
            with self.subTest(cls=cls):
                self.assertEqual(UserId | cls, typing.Union[UserId, cls])
                self.assertEqual(cls | UserId, typing.Union[cls, UserId])

                self.assertEqual(typing.get_args(UserId | cls), (UserId, cls))
                self.assertEqual(typing.get_args(cls | UserId), (cls, UserId))

    def test_special_attrs(self):
        self.assertEqual(UserId.__name__, 'UserId')
        self.assertEqual(UserId.__qualname__, 'UserId')
        self.assertEqual(UserId.__module__, __name__)
        self.assertEqual(UserId.__supertype__, int)

        UserName = self.UserName
        self.assertEqual(UserName.__name__, 'UserName')
        self.assertEqual(UserName.__qualname__,
                         self.__class__.__qualname__ + '.UserName')
        self.assertEqual(UserName.__module__, __name__)
        self.assertEqual(UserName.__supertype__, str)

    def test_repr(self):
        self.assertEqual(repr(UserId), f'{__name__}.UserId')
        self.assertEqual(repr(self.UserName),
                         f'{__name__}.{self.__class__.__qualname__}.UserName')

    def test_pickle(self):
        UserAge = typing.NewType('UserAge', float)
        for proto in range(pickle.HIGHEST_PROTOCOL + 1):
            with self.subTest(proto=proto):
                pickled = pickle.dumps(UserId, proto)
                loaded = pickle.loads(pickled)
                self.assertIs(loaded, UserId)

                pickled = pickle.dumps(self.UserName, proto)
                loaded = pickle.loads(pickled)
                self.assertIs(loaded, self.UserName)

                with self.assertRaises(pickle.PicklingError):
                    pickle.dumps(UserAge, proto)

    def test_missing__name__(self):
        code = ("import typing\n"
                "NT = typing.NewType('NT', int)\n"
                )
        exec(code, {})

    def test_error_message_when_subclassing(self):
        with self.assertRaisesRegex(
            TypeError,
            re.escape(
                "Cannot subclass an instance of NewType. Perhaps you were looking for: "
                "`ProUserId = NewType('ProUserId', UserId)`"
            )
        ):
            class ProUserId(UserId):
                ...


class NamedTupleTests(BaseTestCase):
    class NestedEmployee(NamedTuple):
        name: str
        cool: int

    def test_basics(self):
        Emp = NamedTuple('Emp', [('name', str), ('id', int)])
        self.assertIsSubclass(Emp, tuple)
        joe = Emp('Joe', 42)
        jim = Emp(name='Jim', id=1)
        self.assertIsInstance(joe, Emp)
        self.assertIsInstance(joe, tuple)
        self.assertEqual(joe.name, 'Joe')
        self.assertEqual(joe.id, 42)
        self.assertEqual(jim.name, 'Jim')
        self.assertEqual(jim.id, 1)
        self.assertEqual(Emp.__name__, 'Emp')
        self.assertEqual(Emp._fields, ('name', 'id'))
        self.assertEqual(Emp.__annotations__,
                         collections.OrderedDict([('name', str), ('id', int)]))

    def test_annotation_usage(self):
        tim = CoolEmployee('Tim', 9000)
        self.assertIsInstance(tim, CoolEmployee)
        self.assertIsInstance(tim, tuple)
        self.assertEqual(tim.name, 'Tim')
        self.assertEqual(tim.cool, 9000)
        self.assertEqual(CoolEmployee.__name__, 'CoolEmployee')
        self.assertEqual(CoolEmployee._fields, ('name', 'cool'))
        self.assertEqual(CoolEmployee.__annotations__,
                         collections.OrderedDict(name=str, cool=int))

    def test_annotation_usage_with_default(self):
        jelle = CoolEmployeeWithDefault('Jelle')
        self.assertIsInstance(jelle, CoolEmployeeWithDefault)
        self.assertIsInstance(jelle, tuple)
        self.assertEqual(jelle.name, 'Jelle')
        self.assertEqual(jelle.cool, 0)
        cooler_employee = CoolEmployeeWithDefault('Sjoerd', 1)
        self.assertEqual(cooler_employee.cool, 1)

        self.assertEqual(CoolEmployeeWithDefault.__name__, 'CoolEmployeeWithDefault')
        self.assertEqual(CoolEmployeeWithDefault._fields, ('name', 'cool'))
        self.assertEqual(CoolEmployeeWithDefault.__annotations__,
                         dict(name=str, cool=int))
        self.assertEqual(CoolEmployeeWithDefault._field_defaults, dict(cool=0))

        with self.assertRaises(TypeError):
            class NonDefaultAfterDefault(NamedTuple):
                x: int = 3
                y: int

    def test_annotation_usage_with_methods(self):
        self.assertEqual(XMeth(1).double(), 2)
        self.assertEqual(XMeth(42).x, XMeth(42)[0])
        self.assertEqual(str(XRepr(42)), '42 -> 1')
        self.assertEqual(XRepr(1, 2) + XRepr(3), 0)

        with self.assertRaises(AttributeError):
            class XMethBad(NamedTuple):
                x: int
                def _fields(self):
                    return 'no chance for this'

        with self.assertRaises(AttributeError):
            class XMethBad2(NamedTuple):
                x: int
                def _source(self):
                    return 'no chance for this as well'

    def test_multiple_inheritance(self):
        class A:
            pass
        with self.assertRaises(TypeError):
            class X(NamedTuple, A):
                x: int
        with self.assertRaises(TypeError):
            class Y(NamedTuple, tuple):
                x: int
        with self.assertRaises(TypeError):
            class Z(NamedTuple, NamedTuple):
                x: int
        class B(NamedTuple):
            x: int
        with self.assertRaises(TypeError):
            class C(NamedTuple, B):
                y: str

    def test_generic(self):
        class X(NamedTuple, Generic[T]):
            x: T
        self.assertEqual(X.__bases__, (tuple, Generic))
        self.assertEqual(X.__orig_bases__, (NamedTuple, Generic[T]))
        self.assertEqual(X.__mro__, (X, tuple, Generic, object))

        class Y(Generic[T], NamedTuple):
            x: T
        self.assertEqual(Y.__bases__, (Generic, tuple))
        self.assertEqual(Y.__orig_bases__, (Generic[T], NamedTuple))
        self.assertEqual(Y.__mro__, (Y, Generic, tuple, object))

        for G in X, Y:
            with self.subTest(type=G):
                self.assertEqual(G.__parameters__, (T,))
                self.assertEqual(G[T].__args__, (T,))
                self.assertEqual(get_args(G[T]), (T,))
                A = G[int]
                self.assertIs(A.__origin__, G)
                self.assertEqual(A.__args__, (int,))
                self.assertEqual(get_args(A), (int,))
                self.assertEqual(A.__parameters__, ())

                a = A(3)
                self.assertIs(type(a), G)
                self.assertEqual(a.x, 3)

                with self.assertRaises(TypeError):
                    G[int, str]

    def test_generic_pep695(self):
        class X[T](NamedTuple):
            x: T
        T, = X.__type_params__
        self.assertIsInstance(T, TypeVar)
        self.assertEqual(T.__name__, 'T')
        self.assertEqual(X.__bases__, (tuple, Generic))
        self.assertEqual(X.__orig_bases__, (NamedTuple, Generic[T]))
        self.assertEqual(X.__mro__, (X, tuple, Generic, object))
        self.assertEqual(X.__parameters__, (T,))
        self.assertEqual(X[str].__args__, (str,))
        self.assertEqual(X[str].__parameters__, ())

    def test_non_generic_subscript(self):
        # For backward compatibility, subscription works
        # on arbitrary NamedTuple types.
        class Group(NamedTuple):
            key: T
            group: list[T]
        A = Group[int]
        self.assertEqual(A.__origin__, Group)
        self.assertEqual(A.__parameters__, ())
        self.assertEqual(A.__args__, (int,))
        a = A(1, [2])
        self.assertIs(type(a), Group)
        self.assertEqual(a, (1, [2]))

    def test_namedtuple_keyword_usage(self):
        with self.assertWarnsRegex(
            DeprecationWarning,
            "Creating NamedTuple classes using keyword arguments is deprecated"
        ):
            LocalEmployee = NamedTuple("LocalEmployee", name=str, age=int)

        nick = LocalEmployee('Nick', 25)
        self.assertIsInstance(nick, tuple)
        self.assertEqual(nick.name, 'Nick')
        self.assertEqual(LocalEmployee.__name__, 'LocalEmployee')
        self.assertEqual(LocalEmployee._fields, ('name', 'age'))
        self.assertEqual(LocalEmployee.__annotations__, dict(name=str, age=int))

        with self.assertRaisesRegex(
            TypeError,
            "Either list of fields or keywords can be provided to NamedTuple, not both"
        ):
            NamedTuple('Name', [('x', int)], y=str)

        with self.assertRaisesRegex(
            TypeError,
            "Either list of fields or keywords can be provided to NamedTuple, not both"
        ):
            NamedTuple('Name', [], y=str)

        with self.assertRaisesRegex(
            TypeError,
            (
                r"Cannot pass `None` as the 'fields' parameter "
                r"and also specify fields using keyword arguments"
            )
        ):
            NamedTuple('Name', None, x=int)

    def test_namedtuple_special_keyword_names(self):
        with self.assertWarnsRegex(
            DeprecationWarning,
            "Creating NamedTuple classes using keyword arguments is deprecated"
        ):
            NT = NamedTuple("NT", cls=type, self=object, typename=str, fields=list)

        self.assertEqual(NT.__name__, 'NT')
        self.assertEqual(NT._fields, ('cls', 'self', 'typename', 'fields'))
        a = NT(cls=str, self=42, typename='foo', fields=[('bar', tuple)])
        self.assertEqual(a.cls, str)
        self.assertEqual(a.self, 42)
        self.assertEqual(a.typename, 'foo')
        self.assertEqual(a.fields, [('bar', tuple)])

    def test_empty_namedtuple(self):
        expected_warning = re.escape(
            "Failing to pass a value for the 'fields' parameter is deprecated "
            "and will be disallowed in Python 3.15. "
            "To create a NamedTuple class with 0 fields "
            "using the functional syntax, "
            "pass an empty list, e.g. `NT1 = NamedTuple('NT1', [])`."
        )
        with self.assertWarnsRegex(DeprecationWarning, fr"^{expected_warning}$"):
            NT1 = NamedTuple('NT1')

        expected_warning = re.escape(
            "Passing `None` as the 'fields' parameter is deprecated "
            "and will be disallowed in Python 3.15. "
            "To create a NamedTuple class with 0 fields "
            "using the functional syntax, "
            "pass an empty list, e.g. `NT2 = NamedTuple('NT2', [])`."
        )
        with self.assertWarnsRegex(DeprecationWarning, fr"^{expected_warning}$"):
            NT2 = NamedTuple('NT2', None)

        NT3 = NamedTuple('NT2', [])

        class CNT(NamedTuple):
            pass  # empty body

        for struct in NT1, NT2, NT3, CNT:
            with self.subTest(struct=struct):
                self.assertEqual(struct._fields, ())
                self.assertEqual(struct._field_defaults, {})
                self.assertEqual(struct.__annotations__, {})
                self.assertIsInstance(struct(), struct)

    def test_namedtuple_errors(self):
        with self.assertRaises(TypeError):
            NamedTuple.__new__()

        with self.assertRaisesRegex(
            TypeError,
            "missing 1 required positional argument"
        ):
            NamedTuple()

        with self.assertRaisesRegex(
            TypeError,
            "takes from 1 to 2 positional arguments but 3 were given"
        ):
            NamedTuple('Emp', [('name', str)], None)

        with self.assertRaisesRegex(
            ValueError,
            "Field names cannot start with an underscore"
        ):
            NamedTuple('Emp', [('_name', str)])

        with self.assertRaisesRegex(
            TypeError,
            "missing 1 required positional argument: 'typename'"
        ):
            NamedTuple(typename='Emp', name=str, id=int)

    def test_copy_and_pickle(self):
        global Emp  # pickle wants to reference the class by name
        Emp = NamedTuple('Emp', [('name', str), ('cool', int)])
        for cls in Emp, CoolEmployee, self.NestedEmployee:
            with self.subTest(cls=cls):
                jane = cls('jane', 37)
                for proto in range(pickle.HIGHEST_PROTOCOL + 1):
                    z = pickle.dumps(jane, proto)
                    jane2 = pickle.loads(z)
                    self.assertEqual(jane2, jane)
                    self.assertIsInstance(jane2, cls)

                jane2 = copy(jane)
                self.assertEqual(jane2, jane)
                self.assertIsInstance(jane2, cls)

                jane2 = deepcopy(jane)
                self.assertEqual(jane2, jane)
                self.assertIsInstance(jane2, cls)

    def test_orig_bases(self):
        T = TypeVar('T')

        class SimpleNamedTuple(NamedTuple):
            pass

        class GenericNamedTuple(NamedTuple, Generic[T]):
            pass

        self.assertEqual(SimpleNamedTuple.__orig_bases__, (NamedTuple,))
        self.assertEqual(GenericNamedTuple.__orig_bases__, (NamedTuple, Generic[T]))

        CallNamedTuple = NamedTuple('CallNamedTuple', [])

        self.assertEqual(CallNamedTuple.__orig_bases__, (NamedTuple,))

    def test_setname_called_on_values_in_class_dictionary(self):
        class Vanilla:
            def __set_name__(self, owner, name):
                self.name = name

        class Foo(NamedTuple):
            attr = Vanilla()

        foo = Foo()
        self.assertEqual(len(foo), 0)
        self.assertNotIn('attr', Foo._fields)
        self.assertIsInstance(foo.attr, Vanilla)
        self.assertEqual(foo.attr.name, "attr")

        class Bar(NamedTuple):
            attr: Vanilla = Vanilla()

        bar = Bar()
        self.assertEqual(len(bar), 1)
        self.assertIn('attr', Bar._fields)
        self.assertIsInstance(bar.attr, Vanilla)
        self.assertEqual(bar.attr.name, "attr")

    def test_setname_raises_the_same_as_on_other_classes(self):
        class CustomException(BaseException): pass

        class Annoying:
            def __set_name__(self, owner, name):
                raise CustomException

        annoying = Annoying()

        with self.assertRaises(CustomException) as cm:
            class NormalClass:
                attr = annoying
        normal_exception = cm.exception

        with self.assertRaises(CustomException) as cm:
            class NamedTupleClass(NamedTuple):
                attr = annoying
        namedtuple_exception = cm.exception

        self.assertIs(type(namedtuple_exception), CustomException)
        self.assertIs(type(namedtuple_exception), type(normal_exception))

        self.assertEqual(len(namedtuple_exception.__notes__), 1)
        self.assertEqual(
            len(namedtuple_exception.__notes__), len(normal_exception.__notes__)
        )

        expected_note = (
            "Error calling __set_name__ on 'Annoying' instance "
            "'attr' in 'NamedTupleClass'"
        )
        self.assertEqual(namedtuple_exception.__notes__[0], expected_note)
        self.assertEqual(
            namedtuple_exception.__notes__[0],
            normal_exception.__notes__[0].replace("NormalClass", "NamedTupleClass")
        )

    def test_strange_errors_when_accessing_set_name_itself(self):
        class CustomException(Exception): pass

        class Meta(type):
            def __getattribute__(self, attr):
                if attr == "__set_name__":
                    raise CustomException
                return object.__getattribute__(self, attr)

        class VeryAnnoying(metaclass=Meta): pass

        very_annoying = VeryAnnoying()

        with self.assertRaises(CustomException):
            class Foo(NamedTuple):
                attr = very_annoying


class TypedDictTests(BaseTestCase):
    def test_basics_functional_syntax(self):
        Emp = TypedDict('Emp', {'name': str, 'id': int})
        self.assertIsSubclass(Emp, dict)
        self.assertIsSubclass(Emp, typing.MutableMapping)
        self.assertNotIsSubclass(Emp, collections.abc.Sequence)
        jim = Emp(name='Jim', id=1)
        self.assertIs(type(jim), dict)
        self.assertEqual(jim['name'], 'Jim')
        self.assertEqual(jim['id'], 1)
        self.assertEqual(Emp.__name__, 'Emp')
        self.assertEqual(Emp.__module__, __name__)
        self.assertEqual(Emp.__bases__, (dict,))
        self.assertEqual(Emp.__annotations__, {'name': str, 'id': int})
        self.assertEqual(Emp.__total__, True)
        self.assertEqual(Emp.__required_keys__, {'name', 'id'})
        self.assertIsInstance(Emp.__required_keys__, frozenset)
        self.assertEqual(Emp.__optional_keys__, set())
        self.assertIsInstance(Emp.__optional_keys__, frozenset)

    def test_typeddict_create_errors(self):
        with self.assertRaises(TypeError):
            TypedDict.__new__()
        with self.assertRaises(TypeError):
            TypedDict()
        with self.assertRaises(TypeError):
            TypedDict('Emp', [('name', str)], None)
        with self.assertRaises(TypeError):
            TypedDict(_typename='Emp')
        with self.assertRaises(TypeError):
            TypedDict('Emp', name=str, id=int)

    def test_typeddict_errors(self):
        Emp = TypedDict('Emp', {'name': str, 'id': int})
        self.assertEqual(TypedDict.__module__, 'typing')
        jim = Emp(name='Jim', id=1)
        with self.assertRaises(TypeError):
            isinstance({}, Emp)
        with self.assertRaises(TypeError):
            isinstance(jim, Emp)
        with self.assertRaises(TypeError):
            issubclass(dict, Emp)
        with self.assertRaises(TypeError):
            TypedDict('Hi', [('x', int)], y=int)

    def test_py36_class_syntax_usage(self):
        self.assertEqual(LabelPoint2D.__name__, 'LabelPoint2D')
        self.assertEqual(LabelPoint2D.__module__, __name__)
        self.assertEqual(LabelPoint2D.__annotations__, {'x': int, 'y': int, 'label': str})
        self.assertEqual(LabelPoint2D.__bases__, (dict,))
        self.assertEqual(LabelPoint2D.__total__, True)
        self.assertNotIsSubclass(LabelPoint2D, typing.Sequence)
        not_origin = Point2D(x=0, y=1)
        self.assertEqual(not_origin['x'], 0)
        self.assertEqual(not_origin['y'], 1)
        other = LabelPoint2D(x=0, y=1, label='hi')
        self.assertEqual(other['label'], 'hi')

    def test_pickle(self):
        global EmpD  # pickle wants to reference the class by name
        EmpD = TypedDict('EmpD', {'name': str, 'id': int})
        jane = EmpD({'name': 'jane', 'id': 37})
        for proto in range(pickle.HIGHEST_PROTOCOL + 1):
            z = pickle.dumps(jane, proto)
            jane2 = pickle.loads(z)
            self.assertEqual(jane2, jane)
            self.assertEqual(jane2, {'name': 'jane', 'id': 37})
            ZZ = pickle.dumps(EmpD, proto)
            EmpDnew = pickle.loads(ZZ)
            self.assertEqual(EmpDnew({'name': 'jane', 'id': 37}), jane)

    def test_pickle_generic(self):
        point = Point2DGeneric(a=5.0, b=3.0)
        for proto in range(pickle.HIGHEST_PROTOCOL + 1):
            z = pickle.dumps(point, proto)
            point2 = pickle.loads(z)
            self.assertEqual(point2, point)
            self.assertEqual(point2, {'a': 5.0, 'b': 3.0})
            ZZ = pickle.dumps(Point2DGeneric, proto)
            Point2DGenericNew = pickle.loads(ZZ)
            self.assertEqual(Point2DGenericNew({'a': 5.0, 'b': 3.0}), point)

    def test_optional(self):
        EmpD = TypedDict('EmpD', {'name': str, 'id': int})

        self.assertEqual(typing.Optional[EmpD], typing.Union[None, EmpD])
        self.assertNotEqual(typing.List[EmpD], typing.Tuple[EmpD])

    def test_total(self):
        D = TypedDict('D', {'x': int}, total=False)
        self.assertEqual(D(), {})
        self.assertEqual(D(x=1), {'x': 1})
        self.assertEqual(D.__total__, False)
        self.assertEqual(D.__required_keys__, frozenset())
        self.assertIsInstance(D.__required_keys__, frozenset)
        self.assertEqual(D.__optional_keys__, {'x'})
        self.assertIsInstance(D.__optional_keys__, frozenset)

        self.assertEqual(Options(), {})
        self.assertEqual(Options(log_level=2), {'log_level': 2})
        self.assertEqual(Options.__total__, False)
        self.assertEqual(Options.__required_keys__, frozenset())
        self.assertEqual(Options.__optional_keys__, {'log_level', 'log_path'})

    def test_total_inherits_non_total(self):
        class TD1(TypedDict, total=False):
            a: int

        self.assertIs(TD1.__total__, False)

        class TD2(TD1):
            b: str

        self.assertIs(TD2.__total__, True)

    def test_optional_keys(self):
        class Point2Dor3D(Point2D, total=False):
            z: int

        self.assertEqual(Point2Dor3D.__required_keys__, frozenset(['x', 'y']))
        self.assertIsInstance(Point2Dor3D.__required_keys__, frozenset)
        self.assertEqual(Point2Dor3D.__optional_keys__, frozenset(['z']))
        self.assertIsInstance(Point2Dor3D.__optional_keys__, frozenset)

    def test_keys_inheritance(self):
        class BaseAnimal(TypedDict):
            name: str

        class Animal(BaseAnimal, total=False):
            voice: str
            tail: bool

        class Cat(Animal):
            fur_color: str

        self.assertEqual(BaseAnimal.__required_keys__, frozenset(['name']))
        self.assertEqual(BaseAnimal.__optional_keys__, frozenset([]))
        self.assertEqual(BaseAnimal.__annotations__, {'name': str})

        self.assertEqual(Animal.__required_keys__, frozenset(['name']))
        self.assertEqual(Animal.__optional_keys__, frozenset(['tail', 'voice']))
        self.assertEqual(Animal.__annotations__, {
            'name': str,
            'tail': bool,
            'voice': str,
        })

        self.assertEqual(Cat.__required_keys__, frozenset(['name', 'fur_color']))
        self.assertEqual(Cat.__optional_keys__, frozenset(['tail', 'voice']))
        self.assertEqual(Cat.__annotations__, {
            'fur_color': str,
            'name': str,
            'tail': bool,
            'voice': str,
        })

    def test_keys_inheritance_with_same_name(self):
        class NotTotal(TypedDict, total=False):
            a: int

        class Total(NotTotal):
            a: int

        self.assertEqual(NotTotal.__required_keys__, frozenset())
        self.assertEqual(NotTotal.__optional_keys__, frozenset(['a']))
        self.assertEqual(Total.__required_keys__, frozenset(['a']))
        self.assertEqual(Total.__optional_keys__, frozenset())

        class Base(TypedDict):
            a: NotRequired[int]
            b: Required[int]

        class Child(Base):
            a: Required[int]
            b: NotRequired[int]

        self.assertEqual(Base.__required_keys__, frozenset(['b']))
        self.assertEqual(Base.__optional_keys__, frozenset(['a']))
        self.assertEqual(Child.__required_keys__, frozenset(['a']))
        self.assertEqual(Child.__optional_keys__, frozenset(['b']))

    def test_multiple_inheritance_with_same_key(self):
        class Base1(TypedDict):
            a: NotRequired[int]

        class Base2(TypedDict):
            a: Required[str]

        class Child(Base1, Base2):
            pass

        # Last base wins
        self.assertEqual(Child.__annotations__, {'a': Required[str]})
        self.assertEqual(Child.__required_keys__, frozenset(['a']))
        self.assertEqual(Child.__optional_keys__, frozenset())

    def test_required_notrequired_keys(self):
        self.assertEqual(NontotalMovie.__required_keys__,
                         frozenset({"title"}))
        self.assertEqual(NontotalMovie.__optional_keys__,
                         frozenset({"year"}))

        self.assertEqual(TotalMovie.__required_keys__,
                         frozenset({"title"}))
        self.assertEqual(TotalMovie.__optional_keys__,
                         frozenset({"year"}))

        self.assertEqual(_typed_dict_helper.VeryAnnotated.__required_keys__,
                         frozenset())
        self.assertEqual(_typed_dict_helper.VeryAnnotated.__optional_keys__,
                         frozenset({"a"}))

        self.assertEqual(AnnotatedMovie.__required_keys__,
                         frozenset({"title"}))
        self.assertEqual(AnnotatedMovie.__optional_keys__,
                         frozenset({"year"}))

        self.assertEqual(WeirdlyQuotedMovie.__required_keys__,
                         frozenset({"title"}))
        self.assertEqual(WeirdlyQuotedMovie.__optional_keys__,
                         frozenset({"year"}))

        self.assertEqual(ChildTotalMovie.__required_keys__,
                         frozenset({"title"}))
        self.assertEqual(ChildTotalMovie.__optional_keys__,
                         frozenset({"year"}))

        self.assertEqual(ChildDeeplyAnnotatedMovie.__required_keys__,
                         frozenset({"title"}))
        self.assertEqual(ChildDeeplyAnnotatedMovie.__optional_keys__,
                         frozenset({"year"}))

    def test_multiple_inheritance(self):
        class One(TypedDict):
            one: int
        class Two(TypedDict):
            two: str
        class Untotal(TypedDict, total=False):
            untotal: str
        Inline = TypedDict('Inline', {'inline': bool})
        class Regular:
            pass

        class Child(One, Two):
            child: bool
        self.assertEqual(
            Child.__required_keys__,
            frozenset(['one', 'two', 'child']),
        )
        self.assertEqual(
            Child.__optional_keys__,
            frozenset([]),
        )
        self.assertEqual(
            Child.__annotations__,
            {'one': int, 'two': str, 'child': bool},
        )

        class ChildWithOptional(One, Untotal):
            child: bool
        self.assertEqual(
            ChildWithOptional.__required_keys__,
            frozenset(['one', 'child']),
        )
        self.assertEqual(
            ChildWithOptional.__optional_keys__,
            frozenset(['untotal']),
        )
        self.assertEqual(
            ChildWithOptional.__annotations__,
            {'one': int, 'untotal': str, 'child': bool},
        )

        class ChildWithTotalFalse(One, Untotal, total=False):
            child: bool
        self.assertEqual(
            ChildWithTotalFalse.__required_keys__,
            frozenset(['one']),
        )
        self.assertEqual(
            ChildWithTotalFalse.__optional_keys__,
            frozenset(['untotal', 'child']),
        )
        self.assertEqual(
            ChildWithTotalFalse.__annotations__,
            {'one': int, 'untotal': str, 'child': bool},
        )

        class ChildWithInlineAndOptional(Untotal, Inline):
            child: bool
        self.assertEqual(
            ChildWithInlineAndOptional.__required_keys__,
            frozenset(['inline', 'child']),
        )
        self.assertEqual(
            ChildWithInlineAndOptional.__optional_keys__,
            frozenset(['untotal']),
        )
        self.assertEqual(
            ChildWithInlineAndOptional.__annotations__,
            {'inline': bool, 'untotal': str, 'child': bool},
        )

        wrong_bases = [
            (One, Regular),
            (Regular, One),
            (One, Two, Regular),
            (Inline, Regular),
            (Untotal, Regular),
        ]
        for bases in wrong_bases:
            with self.subTest(bases=bases):
                with self.assertRaisesRegex(
                    TypeError,
                    'cannot inherit from both a TypedDict type and a non-TypedDict',
                ):
                    class Wrong(*bases):
                        pass

    def test_is_typeddict(self):
        self.assertIs(is_typeddict(Point2D), True)
        self.assertIs(is_typeddict(Union[str, int]), False)
        # classes, not instances
        self.assertIs(is_typeddict(Point2D()), False)
        call_based = TypedDict('call_based', {'a': int})
        self.assertIs(is_typeddict(call_based), True)
        self.assertIs(is_typeddict(call_based()), False)

        T = TypeVar("T")
        class BarGeneric(TypedDict, Generic[T]):
            a: T
        self.assertIs(is_typeddict(BarGeneric), True)
        self.assertIs(is_typeddict(BarGeneric[int]), False)
        self.assertIs(is_typeddict(BarGeneric()), False)

        class NewGeneric[T](TypedDict):
            a: T
        self.assertIs(is_typeddict(NewGeneric), True)
        self.assertIs(is_typeddict(NewGeneric[int]), False)
        self.assertIs(is_typeddict(NewGeneric()), False)

        # The TypedDict constructor is not itself a TypedDict
        self.assertIs(is_typeddict(TypedDict), False)

    def test_get_type_hints(self):
        self.assertEqual(
            get_type_hints(Bar),
            {'a': typing.Optional[int], 'b': int}
        )

    def test_get_type_hints_generic(self):
        self.assertEqual(
            get_type_hints(BarGeneric),
            {'a': typing.Optional[T], 'b': int}
        )

        class FooBarGeneric(BarGeneric[int]):
            c: str

        self.assertEqual(
            get_type_hints(FooBarGeneric),
            {'a': typing.Optional[T], 'b': int, 'c': str}
        )

    def test_pep695_generic_typeddict(self):
        class A[T](TypedDict):
            a: T

        T, = A.__type_params__
        self.assertIsInstance(T, TypeVar)
        self.assertEqual(T.__name__, 'T')
        self.assertEqual(A.__bases__, (Generic, dict))
        self.assertEqual(A.__orig_bases__, (TypedDict, Generic[T]))
        self.assertEqual(A.__mro__, (A, Generic, dict, object))
        self.assertEqual(A.__parameters__, (T,))
        self.assertEqual(A[str].__parameters__, ())
        self.assertEqual(A[str].__args__, (str,))

    def test_generic_inheritance(self):
        class A(TypedDict, Generic[T]):
            a: T

        self.assertEqual(A.__bases__, (Generic, dict))
        self.assertEqual(A.__orig_bases__, (TypedDict, Generic[T]))
        self.assertEqual(A.__mro__, (A, Generic, dict, object))
        self.assertEqual(A.__parameters__, (T,))
        self.assertEqual(A[str].__parameters__, ())
        self.assertEqual(A[str].__args__, (str,))

        class A2(Generic[T], TypedDict):
            a: T

        self.assertEqual(A2.__bases__, (Generic, dict))
        self.assertEqual(A2.__orig_bases__, (Generic[T], TypedDict))
        self.assertEqual(A2.__mro__, (A2, Generic, dict, object))
        self.assertEqual(A2.__parameters__, (T,))
        self.assertEqual(A2[str].__parameters__, ())
        self.assertEqual(A2[str].__args__, (str,))

        class B(A[KT], total=False):
            b: KT

        self.assertEqual(B.__bases__, (Generic, dict))
        self.assertEqual(B.__orig_bases__, (A[KT],))
        self.assertEqual(B.__mro__, (B, Generic, dict, object))
        self.assertEqual(B.__parameters__, (KT,))
        self.assertEqual(B.__total__, False)
        self.assertEqual(B.__optional_keys__, frozenset(['b']))
        self.assertEqual(B.__required_keys__, frozenset(['a']))

        self.assertEqual(B[str].__parameters__, ())
        self.assertEqual(B[str].__args__, (str,))
        self.assertEqual(B[str].__origin__, B)

        class C(B[int]):
            c: int

        self.assertEqual(C.__bases__, (Generic, dict))
        self.assertEqual(C.__orig_bases__, (B[int],))
        self.assertEqual(C.__mro__, (C, Generic, dict, object))
        self.assertEqual(C.__parameters__, ())
        self.assertEqual(C.__total__, True)
        self.assertEqual(C.__optional_keys__, frozenset(['b']))
        self.assertEqual(C.__required_keys__, frozenset(['a', 'c']))
        self.assertEqual(C.__annotations__, {
            'a': T,
            'b': KT,
            'c': int,
        })
        with self.assertRaises(TypeError):
            C[str]


        class Point3D(Point2DGeneric[T], Generic[T, KT]):
            c: KT

        self.assertEqual(Point3D.__bases__, (Generic, dict))
        self.assertEqual(Point3D.__orig_bases__, (Point2DGeneric[T], Generic[T, KT]))
        self.assertEqual(Point3D.__mro__, (Point3D, Generic, dict, object))
        self.assertEqual(Point3D.__parameters__, (T, KT))
        self.assertEqual(Point3D.__total__, True)
        self.assertEqual(Point3D.__optional_keys__, frozenset())
        self.assertEqual(Point3D.__required_keys__, frozenset(['a', 'b', 'c']))
        self.assertEqual(Point3D.__annotations__, {
            'a': T,
            'b': T,
            'c': KT,
        })
        self.assertEqual(Point3D[int, str].__origin__, Point3D)

        with self.assertRaises(TypeError):
            Point3D[int]

        with self.assertRaises(TypeError):
            class Point3D(Point2DGeneric[T], Generic[KT]):
                c: KT

    def test_implicit_any_inheritance(self):
        class A(TypedDict, Generic[T]):
            a: T

        class B(A[KT], total=False):
            b: KT

        class WithImplicitAny(B):
            c: int

        self.assertEqual(WithImplicitAny.__bases__, (Generic, dict,))
        self.assertEqual(WithImplicitAny.__mro__, (WithImplicitAny, Generic, dict, object))
        # Consistent with GenericTests.test_implicit_any
        self.assertEqual(WithImplicitAny.__parameters__, ())
        self.assertEqual(WithImplicitAny.__total__, True)
        self.assertEqual(WithImplicitAny.__optional_keys__, frozenset(['b']))
        self.assertEqual(WithImplicitAny.__required_keys__, frozenset(['a', 'c']))
        self.assertEqual(WithImplicitAny.__annotations__, {
            'a': T,
            'b': KT,
            'c': int,
        })
        with self.assertRaises(TypeError):
            WithImplicitAny[str]

    def test_non_generic_subscript(self):
        # For backward compatibility, subscription works
        # on arbitrary TypedDict types.
        class TD(TypedDict):
            a: T
        A = TD[int]
        self.assertEqual(A.__origin__, TD)
        self.assertEqual(A.__parameters__, ())
        self.assertEqual(A.__args__, (int,))
        a = A(a = 1)
        self.assertIs(type(a), dict)
        self.assertEqual(a, {'a': 1})

    def test_orig_bases(self):
        T = TypeVar('T')

        class Parent(TypedDict):
            pass

        class Child(Parent):
            pass

        class OtherChild(Parent):
            pass

        class MixedChild(Child, OtherChild, Parent):
            pass

        class GenericParent(TypedDict, Generic[T]):
            pass

        class GenericChild(GenericParent[int]):
            pass

        class OtherGenericChild(GenericParent[str]):
            pass

        class MixedGenericChild(GenericChild, OtherGenericChild, GenericParent[float]):
            pass

        class MultipleGenericBases(GenericParent[int], GenericParent[float]):
            pass

        CallTypedDict = TypedDict('CallTypedDict', {})

        self.assertEqual(Parent.__orig_bases__, (TypedDict,))
        self.assertEqual(Child.__orig_bases__, (Parent,))
        self.assertEqual(OtherChild.__orig_bases__, (Parent,))
        self.assertEqual(MixedChild.__orig_bases__, (Child, OtherChild, Parent,))
        self.assertEqual(GenericParent.__orig_bases__, (TypedDict, Generic[T]))
        self.assertEqual(GenericChild.__orig_bases__, (GenericParent[int],))
        self.assertEqual(OtherGenericChild.__orig_bases__, (GenericParent[str],))
        self.assertEqual(MixedGenericChild.__orig_bases__, (GenericChild, OtherGenericChild, GenericParent[float]))
        self.assertEqual(MultipleGenericBases.__orig_bases__, (GenericParent[int], GenericParent[float]))
        self.assertEqual(CallTypedDict.__orig_bases__, (TypedDict,))

    def test_zero_fields_typeddicts(self):
        T1 = TypedDict("T1", {})
        class T2(TypedDict): pass
        class T3[tvar](TypedDict): pass
        S = TypeVar("S")
        class T4(TypedDict, Generic[S]): pass

        expected_warning = re.escape(
            "Failing to pass a value for the 'fields' parameter is deprecated "
            "and will be disallowed in Python 3.15. "
            "To create a TypedDict class with 0 fields "
            "using the functional syntax, "
            "pass an empty dictionary, e.g. `T5 = TypedDict('T5', {})`."
        )
        with self.assertWarnsRegex(DeprecationWarning, fr"^{expected_warning}$"):
            T5 = TypedDict('T5')

        expected_warning = re.escape(
            "Passing `None` as the 'fields' parameter is deprecated "
            "and will be disallowed in Python 3.15. "
            "To create a TypedDict class with 0 fields "
            "using the functional syntax, "
            "pass an empty dictionary, e.g. `T6 = TypedDict('T6', {})`."
        )
        with self.assertWarnsRegex(DeprecationWarning, fr"^{expected_warning}$"):
            T6 = TypedDict('T6', None)

        for klass in T1, T2, T3, T4, T5, T6:
            with self.subTest(klass=klass.__name__):
                self.assertEqual(klass.__annotations__, {})
                self.assertEqual(klass.__required_keys__, set())
                self.assertEqual(klass.__optional_keys__, set())
                self.assertIsInstance(klass(), dict)

    def test_readonly_inheritance(self):
        class Base1(TypedDict):
            a: ReadOnly[int]

        class Child1(Base1):
            b: str

        self.assertEqual(Child1.__readonly_keys__, frozenset({'a'}))
        self.assertEqual(Child1.__mutable_keys__, frozenset({'b'}))

        class Base2(TypedDict):
            a: ReadOnly[int]

        class Child2(Base2):
            b: str

        self.assertEqual(Child1.__readonly_keys__, frozenset({'a'}))
        self.assertEqual(Child1.__mutable_keys__, frozenset({'b'}))

    def test_cannot_make_mutable_key_readonly(self):
        class Base(TypedDict):
            a: int

        with self.assertRaises(TypeError):
            class Child(Base):
                a: ReadOnly[int]

    def test_can_make_readonly_key_mutable(self):
        class Base(TypedDict):
            a: ReadOnly[int]

        class Child(Base):
            a: int

        self.assertEqual(Child.__readonly_keys__, frozenset())
        self.assertEqual(Child.__mutable_keys__, frozenset({'a'}))

    def test_combine_qualifiers(self):
        class AllTheThings(TypedDict):
            a: Annotated[Required[ReadOnly[int]], "why not"]
            b: Required[Annotated[ReadOnly[int], "why not"]]
            c: ReadOnly[NotRequired[Annotated[int, "why not"]]]
            d: NotRequired[Annotated[int, "why not"]]

        self.assertEqual(AllTheThings.__required_keys__, frozenset({'a', 'b'}))
        self.assertEqual(AllTheThings.__optional_keys__, frozenset({'c', 'd'}))
        self.assertEqual(AllTheThings.__readonly_keys__, frozenset({'a', 'b', 'c'}))
        self.assertEqual(AllTheThings.__mutable_keys__, frozenset({'d'}))

        self.assertEqual(
            get_type_hints(AllTheThings, include_extras=False),
            {'a': int, 'b': int, 'c': int, 'd': int},
        )
        self.assertEqual(
            get_type_hints(AllTheThings, include_extras=True),
            {
                'a': Annotated[Required[ReadOnly[int]], 'why not'],
                'b': Required[Annotated[ReadOnly[int], 'why not']],
                'c': ReadOnly[NotRequired[Annotated[int, 'why not']]],
                'd': NotRequired[Annotated[int, 'why not']],
            },
        )


class RequiredTests(BaseTestCase):

    def test_basics(self):
        with self.assertRaises(TypeError):
            Required[NotRequired]
        with self.assertRaises(TypeError):
            Required[int, str]
        with self.assertRaises(TypeError):
            Required[int][str]

    def test_repr(self):
        self.assertEqual(repr(Required), 'typing.Required')
        cv = Required[int]
        self.assertEqual(repr(cv), 'typing.Required[int]')
        cv = Required[Employee]
        self.assertEqual(repr(cv), f'typing.Required[{__name__}.Employee]')

    def test_cannot_subclass(self):
        with self.assertRaisesRegex(TypeError, CANNOT_SUBCLASS_TYPE):
            class C(type(Required)):
                pass
        with self.assertRaisesRegex(TypeError, CANNOT_SUBCLASS_TYPE):
            class D(type(Required[int])):
                pass
        with self.assertRaisesRegex(TypeError,
                r'Cannot subclass typing\.Required'):
            class E(Required):
                pass
        with self.assertRaisesRegex(TypeError,
                r'Cannot subclass typing\.Required\[int\]'):
            class F(Required[int]):
                pass

    def test_cannot_init(self):
        with self.assertRaises(TypeError):
            Required()
        with self.assertRaises(TypeError):
            type(Required)()
        with self.assertRaises(TypeError):
            type(Required[Optional[int]])()

    def test_no_isinstance(self):
        with self.assertRaises(TypeError):
            isinstance(1, Required[int])
        with self.assertRaises(TypeError):
            issubclass(int, Required)


class NotRequiredTests(BaseTestCase):

    def test_basics(self):
        with self.assertRaises(TypeError):
            NotRequired[Required]
        with self.assertRaises(TypeError):
            NotRequired[int, str]
        with self.assertRaises(TypeError):
            NotRequired[int][str]

    def test_repr(self):
        self.assertEqual(repr(NotRequired), 'typing.NotRequired')
        cv = NotRequired[int]
        self.assertEqual(repr(cv), 'typing.NotRequired[int]')
        cv = NotRequired[Employee]
        self.assertEqual(repr(cv), f'typing.NotRequired[{__name__}.Employee]')

    def test_cannot_subclass(self):
        with self.assertRaisesRegex(TypeError, CANNOT_SUBCLASS_TYPE):
            class C(type(NotRequired)):
                pass
        with self.assertRaisesRegex(TypeError, CANNOT_SUBCLASS_TYPE):
            class D(type(NotRequired[int])):
                pass
        with self.assertRaisesRegex(TypeError,
                r'Cannot subclass typing\.NotRequired'):
            class E(NotRequired):
                pass
        with self.assertRaisesRegex(TypeError,
                r'Cannot subclass typing\.NotRequired\[int\]'):
            class F(NotRequired[int]):
                pass

    def test_cannot_init(self):
        with self.assertRaises(TypeError):
            NotRequired()
        with self.assertRaises(TypeError):
            type(NotRequired)()
        with self.assertRaises(TypeError):
            type(NotRequired[Optional[int]])()

    def test_no_isinstance(self):
        with self.assertRaises(TypeError):
            isinstance(1, NotRequired[int])
        with self.assertRaises(TypeError):
            issubclass(int, NotRequired)


class IOTests(BaseTestCase):

    def test_io(self):

        def stuff(a: IO) -> AnyStr:
            return a.readline()

        a = stuff.__annotations__['a']
        self.assertEqual(a.__parameters__, (AnyStr,))

    def test_textio(self):

        def stuff(a: TextIO) -> str:
            return a.readline()

        a = stuff.__annotations__['a']
        self.assertEqual(a.__parameters__, ())

    def test_binaryio(self):

        def stuff(a: BinaryIO) -> bytes:
            return a.readline()

        a = stuff.__annotations__['a']
        self.assertEqual(a.__parameters__, ())


class RETests(BaseTestCase):
    # Much of this is really testing _TypeAlias.

    def test_basics(self):
        pat = re.compile('[a-z]+', re.I)
        self.assertIsSubclass(pat.__class__, Pattern)
        self.assertIsSubclass(type(pat), Pattern)
        self.assertIsInstance(pat, Pattern)

        mat = pat.search('12345abcde.....')
        self.assertIsSubclass(mat.__class__, Match)
        self.assertIsSubclass(type(mat), Match)
        self.assertIsInstance(mat, Match)

        # these should just work
        Pattern[Union[str, bytes]]
        Match[Union[bytes, str]]

    def test_alias_equality(self):
        self.assertEqual(Pattern[str], Pattern[str])
        self.assertNotEqual(Pattern[str], Pattern[bytes])
        self.assertNotEqual(Pattern[str], Match[str])
        self.assertNotEqual(Pattern[str], str)

    def test_errors(self):
        m = Match[Union[str, bytes]]
        with self.assertRaises(TypeError):
            m[str]
        with self.assertRaises(TypeError):
            # We don't support isinstance().
            isinstance(42, Pattern[str])
        with self.assertRaises(TypeError):
            # We don't support issubclass().
            issubclass(Pattern[bytes], Pattern[str])

    def test_repr(self):
        self.assertEqual(repr(Pattern), 'typing.Pattern')
        self.assertEqual(repr(Pattern[str]), 'typing.Pattern[str]')
        self.assertEqual(repr(Pattern[bytes]), 'typing.Pattern[bytes]')
        self.assertEqual(repr(Match), 'typing.Match')
        self.assertEqual(repr(Match[str]), 'typing.Match[str]')
        self.assertEqual(repr(Match[bytes]), 'typing.Match[bytes]')

    def test_cannot_subclass(self):
        with self.assertRaisesRegex(
            TypeError,
            r"type 're\.Match' is not an acceptable base type",
        ):
            class A(typing.Match):
                pass
        with self.assertRaisesRegex(
            TypeError,
            r"type 're\.Pattern' is not an acceptable base type",
        ):
            class B(typing.Pattern):
                pass


class AnnotatedTests(BaseTestCase):

    def test_new(self):
        with self.assertRaisesRegex(
            TypeError, 'Cannot instantiate typing.Annotated',
        ):
            Annotated()

    def test_repr(self):
        self.assertEqual(
            repr(Annotated[int, 4, 5]),
            "typing.Annotated[int, 4, 5]"
        )
        self.assertEqual(
            repr(Annotated[List[int], 4, 5]),
            "typing.Annotated[typing.List[int], 4, 5]"
        )

    def test_dir(self):
        dir_items = set(dir(Annotated[int, 4]))
        for required_item in [
            '__args__', '__parameters__', '__origin__',
            '__metadata__',
        ]:
            with self.subTest(required_item=required_item):
                self.assertIn(required_item, dir_items)

    def test_flatten(self):
        A = Annotated[Annotated[int, 4], 5]
        self.assertEqual(A, Annotated[int, 4, 5])
        self.assertEqual(A.__metadata__, (4, 5))
        self.assertEqual(A.__origin__, int)

    def test_deduplicate_from_union(self):
        # Regular:
        self.assertEqual(get_args(Annotated[int, 1] | int),
                         (Annotated[int, 1], int))
        self.assertEqual(get_args(Union[Annotated[int, 1], int]),
                         (Annotated[int, 1], int))
        self.assertEqual(get_args(Annotated[int, 1] | Annotated[int, 2] | int),
                         (Annotated[int, 1], Annotated[int, 2], int))
        self.assertEqual(get_args(Union[Annotated[int, 1], Annotated[int, 2], int]),
                         (Annotated[int, 1], Annotated[int, 2], int))
        self.assertEqual(get_args(Annotated[int, 1] | Annotated[str, 1] | int),
                         (Annotated[int, 1], Annotated[str, 1], int))
        self.assertEqual(get_args(Union[Annotated[int, 1], Annotated[str, 1], int]),
                         (Annotated[int, 1], Annotated[str, 1], int))

        # Duplicates:
        self.assertEqual(Annotated[int, 1] | Annotated[int, 1] | int,
                         Annotated[int, 1] | int)
        self.assertEqual(Union[Annotated[int, 1], Annotated[int, 1], int],
                         Union[Annotated[int, 1], int])

        # Unhashable metadata:
        self.assertEqual(get_args(str | Annotated[int, {}] | Annotated[int, set()] | int),
                         (str, Annotated[int, {}], Annotated[int, set()], int))
        self.assertEqual(get_args(Union[str, Annotated[int, {}], Annotated[int, set()], int]),
                         (str, Annotated[int, {}], Annotated[int, set()], int))
        self.assertEqual(get_args(str | Annotated[int, {}] | Annotated[str, {}] | int),
                         (str, Annotated[int, {}], Annotated[str, {}], int))
        self.assertEqual(get_args(Union[str, Annotated[int, {}], Annotated[str, {}], int]),
                         (str, Annotated[int, {}], Annotated[str, {}], int))

        self.assertEqual(get_args(Annotated[int, 1] | str | Annotated[str, {}] | int),
                         (Annotated[int, 1], str, Annotated[str, {}], int))
        self.assertEqual(get_args(Union[Annotated[int, 1], str, Annotated[str, {}], int]),
                         (Annotated[int, 1], str, Annotated[str, {}], int))

        import dataclasses
        @dataclasses.dataclass
        class ValueRange:
            lo: int
            hi: int
        v = ValueRange(1, 2)
        self.assertEqual(get_args(Annotated[int, v] | None),
                         (Annotated[int, v], types.NoneType))
        self.assertEqual(get_args(Union[Annotated[int, v], None]),
                         (Annotated[int, v], types.NoneType))
        self.assertEqual(get_args(Optional[Annotated[int, v]]),
                         (Annotated[int, v], types.NoneType))

        # Unhashable metadata duplicated:
        self.assertEqual(Annotated[int, {}] | Annotated[int, {}] | int,
                         Annotated[int, {}] | int)
        self.assertEqual(Annotated[int, {}] | Annotated[int, {}] | int,
                         int | Annotated[int, {}])
        self.assertEqual(Union[Annotated[int, {}], Annotated[int, {}], int],
                         Union[Annotated[int, {}], int])
        self.assertEqual(Union[Annotated[int, {}], Annotated[int, {}], int],
                         Union[int, Annotated[int, {}]])

    def test_order_in_union(self):
        expr1 = Annotated[int, 1] | str | Annotated[str, {}] | int
        for args in itertools.permutations(get_args(expr1)):
            with self.subTest(args=args):
                self.assertEqual(expr1, reduce(operator.or_, args))

        expr2 = Union[Annotated[int, 1], str, Annotated[str, {}], int]
        for args in itertools.permutations(get_args(expr2)):
            with self.subTest(args=args):
                self.assertEqual(expr2, Union[args])

    def test_specialize(self):
        L = Annotated[List[T], "my decoration"]
        LI = Annotated[List[int], "my decoration"]
        self.assertEqual(L[int], Annotated[List[int], "my decoration"])
        self.assertEqual(L[int].__metadata__, ("my decoration",))
        self.assertEqual(L[int].__origin__, List[int])
        with self.assertRaises(TypeError):
            LI[int]
        with self.assertRaises(TypeError):
            L[int, float]

    def test_hash_eq(self):
        self.assertEqual(len({Annotated[int, 4, 5], Annotated[int, 4, 5]}), 1)
        self.assertNotEqual(Annotated[int, 4, 5], Annotated[int, 5, 4])
        self.assertNotEqual(Annotated[int, 4, 5], Annotated[str, 4, 5])
        self.assertNotEqual(Annotated[int, 4], Annotated[int, 4, 4])
        self.assertEqual(
            {Annotated[int, 4, 5], Annotated[int, 4, 5], Annotated[T, 4, 5]},
            {Annotated[int, 4, 5], Annotated[T, 4, 5]}
        )
        # Unhashable `metadata` raises `TypeError`:
        a1 = Annotated[int, []]
        with self.assertRaises(TypeError):
            hash(a1)

        class A:
            __hash__ = None
        a2 = Annotated[int, A()]
        with self.assertRaises(TypeError):
            hash(a2)

    def test_instantiate(self):
        class C:
            classvar = 4

            def __init__(self, x):
                self.x = x

            def __eq__(self, other):
                if not isinstance(other, C):
                    return NotImplemented
                return other.x == self.x

        A = Annotated[C, "a decoration"]
        a = A(5)
        c = C(5)
        self.assertEqual(a, c)
        self.assertEqual(a.x, c.x)
        self.assertEqual(a.classvar, c.classvar)

    def test_instantiate_generic(self):
        MyCount = Annotated[typing.Counter[T], "my decoration"]
        self.assertEqual(MyCount([4, 4, 5]), {4: 2, 5: 1})
        self.assertEqual(MyCount[int]([4, 4, 5]), {4: 2, 5: 1})

    def test_instantiate_immutable(self):
        class C:
            def __setattr__(self, key, value):
                raise Exception("should be ignored")

        A = Annotated[C, "a decoration"]
        # gh-115165: This used to cause RuntimeError to be raised
        # when we tried to set `__orig_class__` on the `C` instance
        # returned by the `A()` call
        self.assertIsInstance(A(), C)

    def test_cannot_instantiate_forward(self):
        A = Annotated["int", (5, 6)]
        with self.assertRaises(TypeError):
            A(5)

    def test_cannot_instantiate_type_var(self):
        A = Annotated[T, (5, 6)]
        with self.assertRaises(TypeError):
            A(5)

    def test_cannot_getattr_typevar(self):
        with self.assertRaises(AttributeError):
            Annotated[T, (5, 7)].x

    def test_attr_passthrough(self):
        class C:
            classvar = 4

        A = Annotated[C, "a decoration"]
        self.assertEqual(A.classvar, 4)
        A.x = 5
        self.assertEqual(C.x, 5)

    def test_special_form_containment(self):
        class C:
            classvar: Annotated[ClassVar[int], "a decoration"] = 4
            const: Annotated[Final[int], "Const"] = 4

        self.assertEqual(get_type_hints(C, globals())['classvar'], ClassVar[int])
        self.assertEqual(get_type_hints(C, globals())['const'], Final[int])

    def test_special_forms_nesting(self):
        # These are uncommon types and are to ensure runtime
        # is lax on validation. See gh-89547 for more context.
        class CF:
            x: ClassVar[Final[int]]

        class FC:
            x: Final[ClassVar[int]]

        class ACF:
            x: Annotated[ClassVar[Final[int]], "a decoration"]

        class CAF:
            x: ClassVar[Annotated[Final[int], "a decoration"]]

        class AFC:
            x: Annotated[Final[ClassVar[int]], "a decoration"]

        class FAC:
            x: Final[Annotated[ClassVar[int], "a decoration"]]

        self.assertEqual(get_type_hints(CF, globals())['x'], ClassVar[Final[int]])
        self.assertEqual(get_type_hints(FC, globals())['x'], Final[ClassVar[int]])
        self.assertEqual(get_type_hints(ACF, globals())['x'], ClassVar[Final[int]])
        self.assertEqual(get_type_hints(CAF, globals())['x'], ClassVar[Final[int]])
        self.assertEqual(get_type_hints(AFC, globals())['x'], Final[ClassVar[int]])
        self.assertEqual(get_type_hints(FAC, globals())['x'], Final[ClassVar[int]])

    def test_cannot_subclass(self):
        with self.assertRaisesRegex(TypeError, "Cannot subclass .*Annotated"):
            class C(Annotated):
                pass

    def test_cannot_check_instance(self):
        with self.assertRaises(TypeError):
            isinstance(5, Annotated[int, "positive"])

    def test_cannot_check_subclass(self):
        with self.assertRaises(TypeError):
            issubclass(int, Annotated[int, "positive"])

    def test_too_few_type_args(self):
        with self.assertRaisesRegex(TypeError, 'at least two arguments'):
            Annotated[int]

    def test_pickle(self):
        samples = [typing.Any, typing.Union[int, str],
                   typing.Optional[str], Tuple[int, ...],
                   typing.Callable[[str], bytes]]

        for t in samples:
            x = Annotated[t, "a"]

            for prot in range(pickle.HIGHEST_PROTOCOL + 1):
                with self.subTest(protocol=prot, type=t):
                    pickled = pickle.dumps(x, prot)
                    restored = pickle.loads(pickled)
                    self.assertEqual(x, restored)

        global _Annotated_test_G

        class _Annotated_test_G(Generic[T]):
            x = 1

        G = Annotated[_Annotated_test_G[int], "A decoration"]
        G.foo = 42
        G.bar = 'abc'

        for proto in range(pickle.HIGHEST_PROTOCOL + 1):
            z = pickle.dumps(G, proto)
            x = pickle.loads(z)
            self.assertEqual(x.foo, 42)
            self.assertEqual(x.bar, 'abc')
            self.assertEqual(x.x, 1)

    def test_subst(self):
        dec = "a decoration"
        dec2 = "another decoration"

        S = Annotated[T, dec2]
        self.assertEqual(S[int], Annotated[int, dec2])

        self.assertEqual(S[Annotated[int, dec]], Annotated[int, dec, dec2])
        L = Annotated[List[T], dec]

        self.assertEqual(L[int], Annotated[List[int], dec])
        with self.assertRaises(TypeError):
            L[int, int]

        self.assertEqual(S[L[int]], Annotated[List[int], dec, dec2])

        D = Annotated[typing.Dict[KT, VT], dec]
        self.assertEqual(D[str, int], Annotated[typing.Dict[str, int], dec])
        with self.assertRaises(TypeError):
            D[int]

        It = Annotated[int, dec]
        with self.assertRaises(TypeError):
            It[None]

        LI = L[int]
        with self.assertRaises(TypeError):
            LI[None]

    def test_typevar_subst(self):
        dec = "a decoration"
        Ts = TypeVarTuple('Ts')
        T = TypeVar('T')
        T1 = TypeVar('T1')
        T2 = TypeVar('T2')

        A = Annotated[tuple[*Ts], dec]
        self.assertEqual(A[int], Annotated[tuple[int], dec])
        self.assertEqual(A[str, int], Annotated[tuple[str, int], dec])
        with self.assertRaises(TypeError):
            Annotated[*Ts, dec]

        B = Annotated[Tuple[Unpack[Ts]], dec]
        self.assertEqual(B[int], Annotated[Tuple[int], dec])
        self.assertEqual(B[str, int], Annotated[Tuple[str, int], dec])
        with self.assertRaises(TypeError):
            Annotated[Unpack[Ts], dec]

        C = Annotated[tuple[T, *Ts], dec]
        self.assertEqual(C[int], Annotated[tuple[int], dec])
        self.assertEqual(C[int, str], Annotated[tuple[int, str], dec])
        self.assertEqual(
            C[int, str, float],
            Annotated[tuple[int, str, float], dec]
        )
        with self.assertRaises(TypeError):
            C[()]

        D = Annotated[Tuple[T, Unpack[Ts]], dec]
        self.assertEqual(D[int], Annotated[Tuple[int], dec])
        self.assertEqual(D[int, str], Annotated[Tuple[int, str], dec])
        self.assertEqual(
            D[int, str, float],
            Annotated[Tuple[int, str, float], dec]
        )
        with self.assertRaises(TypeError):
            D[()]

        E = Annotated[tuple[*Ts, T], dec]
        self.assertEqual(E[int], Annotated[tuple[int], dec])
        self.assertEqual(E[int, str], Annotated[tuple[int, str], dec])
        self.assertEqual(
            E[int, str, float],
            Annotated[tuple[int, str, float], dec]
        )
        with self.assertRaises(TypeError):
            E[()]

        F = Annotated[Tuple[Unpack[Ts], T], dec]
        self.assertEqual(F[int], Annotated[Tuple[int], dec])
        self.assertEqual(F[int, str], Annotated[Tuple[int, str], dec])
        self.assertEqual(
            F[int, str, float],
            Annotated[Tuple[int, str, float], dec]
        )
        with self.assertRaises(TypeError):
            F[()]

        G = Annotated[tuple[T1, *Ts, T2], dec]
        self.assertEqual(G[int, str], Annotated[tuple[int, str], dec])
        self.assertEqual(
            G[int, str, float],
            Annotated[tuple[int, str, float], dec]
        )
        self.assertEqual(
            G[int, str, bool, float],
            Annotated[tuple[int, str, bool, float], dec]
        )
        with self.assertRaises(TypeError):
            G[int]

        H = Annotated[Tuple[T1, Unpack[Ts], T2], dec]
        self.assertEqual(H[int, str], Annotated[Tuple[int, str], dec])
        self.assertEqual(
            H[int, str, float],
            Annotated[Tuple[int, str, float], dec]
        )
        self.assertEqual(
            H[int, str, bool, float],
            Annotated[Tuple[int, str, bool, float], dec]
        )
        with self.assertRaises(TypeError):
            H[int]

        # Now let's try creating an alias from an alias.

        Ts2 = TypeVarTuple('Ts2')
        T3 = TypeVar('T3')
        T4 = TypeVar('T4')

        # G is Annotated[tuple[T1, *Ts, T2], dec].
        I = G[T3, *Ts2, T4]
        J = G[T3, Unpack[Ts2], T4]

        for x, y in [
            (I,                  Annotated[tuple[T3, *Ts2, T4], dec]),
            (J,                  Annotated[tuple[T3, Unpack[Ts2], T4], dec]),
            (I[int, str],        Annotated[tuple[int, str], dec]),
            (J[int, str],        Annotated[tuple[int, str], dec]),
            (I[int, str, float], Annotated[tuple[int, str, float], dec]),
            (J[int, str, float], Annotated[tuple[int, str, float], dec]),
            (I[int, str, bool, float],
                                 Annotated[tuple[int, str, bool, float], dec]),
            (J[int, str, bool, float],
                                 Annotated[tuple[int, str, bool, float], dec]),
        ]:
            self.assertEqual(x, y)

        with self.assertRaises(TypeError):
            I[int]
        with self.assertRaises(TypeError):
            J[int]

    def test_annotated_in_other_types(self):
        X = List[Annotated[T, 5]]
        self.assertEqual(X[int], List[Annotated[int, 5]])

    def test_annotated_mro(self):
        class X(Annotated[int, (1, 10)]): ...
        self.assertEqual(X.__mro__, (X, int, object),
                         "Annotated should be transparent.")

    def test_annotated_cached_with_types(self):
        class A(str): ...
        class B(str): ...

        field_a1 = Annotated[str, A("X")]
        field_a2 = Annotated[str, B("X")]
        a1_metadata = field_a1.__metadata__[0]
        a2_metadata = field_a2.__metadata__[0]

        self.assertIs(type(a1_metadata), A)
        self.assertEqual(a1_metadata, A("X"))
        self.assertIs(type(a2_metadata), B)
        self.assertEqual(a2_metadata, B("X"))
        self.assertIsNot(type(a1_metadata), type(a2_metadata))

        field_b1 = Annotated[str, A("Y")]
        field_b2 = Annotated[str, B("Y")]
        b1_metadata = field_b1.__metadata__[0]
        b2_metadata = field_b2.__metadata__[0]

        self.assertIs(type(b1_metadata), A)
        self.assertEqual(b1_metadata, A("Y"))
        self.assertIs(type(b2_metadata), B)
        self.assertEqual(b2_metadata, B("Y"))
        self.assertIsNot(type(b1_metadata), type(b2_metadata))

        field_c1 = Annotated[int, 1]
        field_c2 = Annotated[int, 1.0]
        field_c3 = Annotated[int, True]

        self.assertIs(type(field_c1.__metadata__[0]), int)
        self.assertIs(type(field_c2.__metadata__[0]), float)
        self.assertIs(type(field_c3.__metadata__[0]), bool)


class TypeAliasTests(BaseTestCase):
    def test_canonical_usage_with_variable_annotation(self):
        Alias: TypeAlias = Employee

    def test_canonical_usage_with_type_comment(self):
        Alias = Employee  # type: TypeAlias

    def test_cannot_instantiate(self):
        with self.assertRaises(TypeError):
            TypeAlias()

    def test_no_isinstance(self):
        with self.assertRaises(TypeError):
            isinstance(42, TypeAlias)

    def test_stringized_usage(self):
        class A:
            a: "TypeAlias"
        self.assertEqual(get_type_hints(A), {'a': TypeAlias})

    def test_no_issubclass(self):
        with self.assertRaises(TypeError):
            issubclass(Employee, TypeAlias)

        with self.assertRaises(TypeError):
            issubclass(TypeAlias, Employee)

    def test_cannot_subclass(self):
        with self.assertRaisesRegex(TypeError,
                r'Cannot subclass typing\.TypeAlias'):
            class C(TypeAlias):
                pass

        with self.assertRaises(TypeError):
            class D(type(TypeAlias)):
                pass

    def test_repr(self):
        self.assertEqual(repr(TypeAlias), 'typing.TypeAlias')

    def test_cannot_subscript(self):
        with self.assertRaises(TypeError):
            TypeAlias[int]


class ParamSpecTests(BaseTestCase):

    def test_basic_plain(self):
        P = ParamSpec('P')
        self.assertEqual(P, P)
        self.assertIsInstance(P, ParamSpec)
        self.assertEqual(P.__name__, 'P')
        self.assertEqual(P.__module__, __name__)

    def test_basic_with_exec(self):
        ns = {}
        exec('from typing import ParamSpec; P = ParamSpec("P")', ns, ns)
        P = ns['P']
        self.assertIsInstance(P, ParamSpec)
        self.assertEqual(P.__name__, 'P')
        self.assertIs(P.__module__, None)

    def test_valid_uses(self):
        P = ParamSpec('P')
        T = TypeVar('T')
        C1 = Callable[P, int]
        self.assertEqual(C1.__args__, (P, int))
        self.assertEqual(C1.__parameters__, (P,))
        C2 = Callable[P, T]
        self.assertEqual(C2.__args__, (P, T))
        self.assertEqual(C2.__parameters__, (P, T))
        # Test collections.abc.Callable too.
        C3 = collections.abc.Callable[P, int]
        self.assertEqual(C3.__args__, (P, int))
        self.assertEqual(C3.__parameters__, (P,))
        C4 = collections.abc.Callable[P, T]
        self.assertEqual(C4.__args__, (P, T))
        self.assertEqual(C4.__parameters__, (P, T))

    def test_args_kwargs(self):
        P = ParamSpec('P')
        P_2 = ParamSpec('P_2')
        self.assertIn('args', dir(P))
        self.assertIn('kwargs', dir(P))
        self.assertIsInstance(P.args, ParamSpecArgs)
        self.assertIsInstance(P.kwargs, ParamSpecKwargs)
        self.assertIs(P.args.__origin__, P)
        self.assertIs(P.kwargs.__origin__, P)
        self.assertEqual(P.args, P.args)
        self.assertEqual(P.kwargs, P.kwargs)
        self.assertNotEqual(P.args, P_2.args)
        self.assertNotEqual(P.kwargs, P_2.kwargs)
        self.assertNotEqual(P.args, P.kwargs)
        self.assertNotEqual(P.kwargs, P.args)
        self.assertNotEqual(P.args, P_2.kwargs)
        self.assertEqual(repr(P.args), "P.args")
        self.assertEqual(repr(P.kwargs), "P.kwargs")

    def test_stringized(self):
        P = ParamSpec('P')
        class C(Generic[P]):
            func: Callable["P", int]
            def foo(self, *args: "P.args", **kwargs: "P.kwargs"):
                pass

        self.assertEqual(gth(C, globals(), locals()), {"func": Callable[P, int]})
        self.assertEqual(
            gth(C.foo, globals(), locals()), {"args": P.args, "kwargs": P.kwargs}
        )

    def test_user_generics(self):
        T = TypeVar("T")
        P = ParamSpec("P")
        P_2 = ParamSpec("P_2")

        class X(Generic[T, P]):
            f: Callable[P, int]
            x: T
        G1 = X[int, P_2]
        self.assertEqual(G1.__args__, (int, P_2))
        self.assertEqual(G1.__parameters__, (P_2,))
        with self.assertRaisesRegex(TypeError, "few arguments for"):
            X[int]
        with self.assertRaisesRegex(TypeError, "many arguments for"):
            X[int, P_2, str]

        G2 = X[int, Concatenate[int, P_2]]
        self.assertEqual(G2.__args__, (int, Concatenate[int, P_2]))
        self.assertEqual(G2.__parameters__, (P_2,))

        G3 = X[int, [int, bool]]
        self.assertEqual(G3.__args__, (int, (int, bool)))
        self.assertEqual(G3.__parameters__, ())

        G4 = X[int, ...]
        self.assertEqual(G4.__args__, (int, Ellipsis))
        self.assertEqual(G4.__parameters__, ())

        class Z(Generic[P]):
            f: Callable[P, int]

        G5 = Z[[int, str, bool]]
        self.assertEqual(G5.__args__, ((int, str, bool),))
        self.assertEqual(G5.__parameters__, ())

        G6 = Z[int, str, bool]
        self.assertEqual(G6.__args__, ((int, str, bool),))
        self.assertEqual(G6.__parameters__, ())

        # G5 and G6 should be equivalent according to the PEP
        self.assertEqual(G5.__args__, G6.__args__)
        self.assertEqual(G5.__origin__, G6.__origin__)
        self.assertEqual(G5.__parameters__, G6.__parameters__)
        self.assertEqual(G5, G6)

        G7 = Z[int]
        self.assertEqual(G7.__args__, ((int,),))
        self.assertEqual(G7.__parameters__, ())

        with self.assertRaisesRegex(TypeError, "many arguments for"):
            Z[[int, str], bool]
        with self.assertRaisesRegex(TypeError, "many arguments for"):
            Z[P_2, bool]

    def test_multiple_paramspecs_in_user_generics(self):
        P = ParamSpec("P")
        P2 = ParamSpec("P2")

        class X(Generic[P, P2]):
            f: Callable[P, int]
            g: Callable[P2, str]

        G1 = X[[int, str], [bytes]]
        G2 = X[[int], [str, bytes]]
        self.assertNotEqual(G1, G2)
        self.assertEqual(G1.__args__, ((int, str), (bytes,)))
        self.assertEqual(G2.__args__, ((int,), (str, bytes)))

    def test_typevartuple_and_paramspecs_in_user_generics(self):
        Ts = TypeVarTuple("Ts")
        P = ParamSpec("P")

        class X(Generic[*Ts, P]):
            f: Callable[P, int]
            g: Tuple[*Ts]

        G1 = X[int, [bytes]]
        self.assertEqual(G1.__args__, (int, (bytes,)))
        G2 = X[int, str, [bytes]]
        self.assertEqual(G2.__args__, (int, str, (bytes,)))
        G3 = X[[bytes]]
        self.assertEqual(G3.__args__, ((bytes,),))
        G4 = X[[]]
        self.assertEqual(G4.__args__, ((),))
        with self.assertRaises(TypeError):
            X[()]

        class Y(Generic[P, *Ts]):
            f: Callable[P, int]
            g: Tuple[*Ts]

        G1 = Y[[bytes], int]
        self.assertEqual(G1.__args__, ((bytes,), int))
        G2 = Y[[bytes], int, str]
        self.assertEqual(G2.__args__, ((bytes,), int, str))
        G3 = Y[[bytes]]
        self.assertEqual(G3.__args__, ((bytes,),))
        G4 = Y[[]]
        self.assertEqual(G4.__args__, ((),))
        with self.assertRaises(TypeError):
            Y[()]

    def test_typevartuple_and_paramspecs_in_generic_aliases(self):
        P = ParamSpec('P')
        T = TypeVar('T')
        Ts = TypeVarTuple('Ts')

        for C in Callable, collections.abc.Callable:
            with self.subTest(generic=C):
                A = C[P, Tuple[*Ts]]
                B = A[[int, str], bytes, float]
                self.assertEqual(B.__args__, (int, str, Tuple[bytes, float]))

        class X(Generic[T, P]):
            pass

        A = X[Tuple[*Ts], P]
        B = A[bytes, float, [int, str]]
        self.assertEqual(B.__args__, (Tuple[bytes, float], (int, str,)))

        class Y(Generic[P, T]):
            pass

        A = Y[P, Tuple[*Ts]]
        B = A[[int, str], bytes, float]
        self.assertEqual(B.__args__, ((int, str,), Tuple[bytes, float]))

    def test_var_substitution(self):
        P = ParamSpec("P")
        subst = P.__typing_subst__
        self.assertEqual(subst((int, str)), (int, str))
        self.assertEqual(subst([int, str]), (int, str))
        self.assertEqual(subst([None]), (type(None),))
        self.assertIs(subst(...), ...)
        self.assertIs(subst(P), P)
        self.assertEqual(subst(Concatenate[int, P]), Concatenate[int, P])

    def test_bad_var_substitution(self):
        T = TypeVar('T')
        P = ParamSpec('P')
        bad_args = (42, int, None, T, int|str, Union[int, str])
        for arg in bad_args:
            with self.subTest(arg=arg):
                with self.assertRaises(TypeError):
                    P.__typing_subst__(arg)
                with self.assertRaises(TypeError):
                    typing.Callable[P, T][arg, str]
                with self.assertRaises(TypeError):
                    collections.abc.Callable[P, T][arg, str]

    def test_type_var_subst_for_other_type_vars(self):
        T = TypeVar('T')
        T2 = TypeVar('T2')
        P = ParamSpec('P')
        P2 = ParamSpec('P2')
        Ts = TypeVarTuple('Ts')

        class Base(Generic[P]):
            pass

        A1 = Base[T]
        self.assertEqual(A1.__parameters__, (T,))
        self.assertEqual(A1.__args__, ((T,),))
        self.assertEqual(A1[int], Base[int])

        A2 = Base[[T]]
        self.assertEqual(A2.__parameters__, (T,))
        self.assertEqual(A2.__args__, ((T,),))
        self.assertEqual(A2[int], Base[int])

        A3 = Base[[int, T]]
        self.assertEqual(A3.__parameters__, (T,))
        self.assertEqual(A3.__args__, ((int, T),))
        self.assertEqual(A3[str], Base[[int, str]])

        A4 = Base[[T, int, T2]]
        self.assertEqual(A4.__parameters__, (T, T2))
        self.assertEqual(A4.__args__, ((T, int, T2),))
        self.assertEqual(A4[str, bool], Base[[str, int, bool]])

        A5 = Base[[*Ts, int]]
        self.assertEqual(A5.__parameters__, (Ts,))
        self.assertEqual(A5.__args__, ((*Ts, int),))
        self.assertEqual(A5[str, bool], Base[[str, bool, int]])

        A5_2 = Base[[int, *Ts]]
        self.assertEqual(A5_2.__parameters__, (Ts,))
        self.assertEqual(A5_2.__args__, ((int, *Ts),))
        self.assertEqual(A5_2[str, bool], Base[[int, str, bool]])

        A6 = Base[[T, *Ts]]
        self.assertEqual(A6.__parameters__, (T, Ts))
        self.assertEqual(A6.__args__, ((T, *Ts),))
        self.assertEqual(A6[int, str, bool], Base[[int, str, bool]])

        A7 = Base[[T, T]]
        self.assertEqual(A7.__parameters__, (T,))
        self.assertEqual(A7.__args__, ((T, T),))
        self.assertEqual(A7[int], Base[[int, int]])

        A8 = Base[[T, list[T]]]
        self.assertEqual(A8.__parameters__, (T,))
        self.assertEqual(A8.__args__, ((T, list[T]),))
        self.assertEqual(A8[int], Base[[int, list[int]]])

        A9 = Base[[Tuple[*Ts], *Ts]]
        self.assertEqual(A9.__parameters__, (Ts,))
        self.assertEqual(A9.__args__, ((Tuple[*Ts], *Ts),))
        self.assertEqual(A9[int, str], Base[Tuple[int, str], int, str])

        A10 = Base[P2]
        self.assertEqual(A10.__parameters__, (P2,))
        self.assertEqual(A10.__args__, (P2,))
        self.assertEqual(A10[[int, str]], Base[[int, str]])

        class DoubleP(Generic[P, P2]):
            pass

        B1 = DoubleP[P, P2]
        self.assertEqual(B1.__parameters__, (P, P2))
        self.assertEqual(B1.__args__, (P, P2))
        self.assertEqual(B1[[int, str], [bool]], DoubleP[[int,  str], [bool]])
        self.assertEqual(B1[[], []], DoubleP[[], []])

        B2 = DoubleP[[int, str], P2]
        self.assertEqual(B2.__parameters__, (P2,))
        self.assertEqual(B2.__args__, ((int, str), P2))
        self.assertEqual(B2[[bool, bool]], DoubleP[[int,  str], [bool, bool]])
        self.assertEqual(B2[[]], DoubleP[[int,  str], []])

        B3 = DoubleP[P, [bool, bool]]
        self.assertEqual(B3.__parameters__, (P,))
        self.assertEqual(B3.__args__, (P, (bool, bool)))
        self.assertEqual(B3[[int, str]], DoubleP[[int,  str], [bool, bool]])
        self.assertEqual(B3[[]], DoubleP[[], [bool, bool]])

        B4 = DoubleP[[T, int], [bool, T2]]
        self.assertEqual(B4.__parameters__, (T, T2))
        self.assertEqual(B4.__args__, ((T, int), (bool, T2)))
        self.assertEqual(B4[str, float], DoubleP[[str, int], [bool, float]])

        B5 = DoubleP[[*Ts, int], [bool, T2]]
        self.assertEqual(B5.__parameters__, (Ts, T2))
        self.assertEqual(B5.__args__, ((*Ts, int), (bool, T2)))
        self.assertEqual(B5[str, bytes, float],
                         DoubleP[[str, bytes, int], [bool, float]])

        B6 = DoubleP[[T, int], [bool, *Ts]]
        self.assertEqual(B6.__parameters__, (T, Ts))
        self.assertEqual(B6.__args__, ((T, int), (bool, *Ts)))
        self.assertEqual(B6[str, bytes, float],
                         DoubleP[[str, int], [bool, bytes, float]])

        class PandT(Generic[P, T]):
            pass

        C1 = PandT[P, T]
        self.assertEqual(C1.__parameters__, (P, T))
        self.assertEqual(C1.__args__, (P, T))
        self.assertEqual(C1[[int, str], bool], PandT[[int, str], bool])

        C2 = PandT[[int, T], T]
        self.assertEqual(C2.__parameters__, (T,))
        self.assertEqual(C2.__args__, ((int, T), T))
        self.assertEqual(C2[str], PandT[[int, str], str])

        C3 = PandT[[int, *Ts], T]
        self.assertEqual(C3.__parameters__, (Ts, T))
        self.assertEqual(C3.__args__, ((int, *Ts), T))
        self.assertEqual(C3[str, bool, bytes], PandT[[int, str, bool], bytes])

    def test_paramspec_in_nested_generics(self):
        # Although ParamSpec should not be found in __parameters__ of most
        # generics, they probably should be found when nested in
        # a valid location.
        T = TypeVar("T")
        P = ParamSpec("P")
        C1 = Callable[P, T]
        G1 = List[C1]
        G2 = list[C1]
        G3 = list[C1] | int
        self.assertEqual(G1.__parameters__, (P, T))
        self.assertEqual(G2.__parameters__, (P, T))
        self.assertEqual(G3.__parameters__, (P, T))
        C = Callable[[int, str], float]
        self.assertEqual(G1[[int, str], float], List[C])
        self.assertEqual(G2[[int, str], float], list[C])
        self.assertEqual(G3[[int, str], float], list[C] | int)

    def test_paramspec_gets_copied(self):
        # bpo-46581
        P = ParamSpec('P')
        P2 = ParamSpec('P2')
        C1 = Callable[P, int]
        self.assertEqual(C1.__parameters__, (P,))
        self.assertEqual(C1[P2].__parameters__, (P2,))
        self.assertEqual(C1[str].__parameters__, ())
        self.assertEqual(C1[str, T].__parameters__, (T,))
        self.assertEqual(C1[Concatenate[str, P2]].__parameters__, (P2,))
        self.assertEqual(C1[Concatenate[T, P2]].__parameters__, (T, P2))
        self.assertEqual(C1[...].__parameters__, ())

        C2 = Callable[Concatenate[str, P], int]
        self.assertEqual(C2.__parameters__, (P,))
        self.assertEqual(C2[P2].__parameters__, (P2,))
        self.assertEqual(C2[str].__parameters__, ())
        self.assertEqual(C2[str, T].__parameters__, (T,))
        self.assertEqual(C2[Concatenate[str, P2]].__parameters__, (P2,))
        self.assertEqual(C2[Concatenate[T, P2]].__parameters__, (T, P2))

    def test_cannot_subclass(self):
        with self.assertRaisesRegex(TypeError, NOT_A_BASE_TYPE % 'ParamSpec'):
            class C(ParamSpec): pass
        with self.assertRaisesRegex(TypeError, NOT_A_BASE_TYPE % 'ParamSpecArgs'):
            class D(ParamSpecArgs): pass
        with self.assertRaisesRegex(TypeError, NOT_A_BASE_TYPE % 'ParamSpecKwargs'):
            class E(ParamSpecKwargs): pass
        P = ParamSpec('P')
        with self.assertRaisesRegex(TypeError,
                CANNOT_SUBCLASS_INSTANCE % 'ParamSpec'):
            class F(P): pass
        with self.assertRaisesRegex(TypeError,
                CANNOT_SUBCLASS_INSTANCE % 'ParamSpecArgs'):
            class G(P.args): pass
        with self.assertRaisesRegex(TypeError,
                CANNOT_SUBCLASS_INSTANCE % 'ParamSpecKwargs'):
            class H(P.kwargs): pass


class ConcatenateTests(BaseTestCase):
    def test_basics(self):
        P = ParamSpec('P')
        class MyClass: ...
        c = Concatenate[MyClass, P]
        self.assertNotEqual(c, Concatenate)

    def test_dir(self):
        P = ParamSpec('P')
        dir_items = set(dir(Concatenate[int, P]))
        for required_item in [
            '__args__', '__parameters__', '__origin__',
        ]:
            with self.subTest(required_item=required_item):
                self.assertIn(required_item, dir_items)

    def test_valid_uses(self):
        P = ParamSpec('P')
        T = TypeVar('T')
        C1 = Callable[Concatenate[int, P], int]
        self.assertEqual(C1.__args__, (Concatenate[int, P], int))
        self.assertEqual(C1.__parameters__, (P,))
        C2 = Callable[Concatenate[int, T, P], T]
        self.assertEqual(C2.__args__, (Concatenate[int, T, P], T))
        self.assertEqual(C2.__parameters__, (T, P))

        # Test collections.abc.Callable too.
        C3 = collections.abc.Callable[Concatenate[int, P], int]
        self.assertEqual(C3.__args__, (Concatenate[int, P], int))
        self.assertEqual(C3.__parameters__, (P,))
        C4 = collections.abc.Callable[Concatenate[int, T, P], T]
        self.assertEqual(C4.__args__, (Concatenate[int, T, P], T))
        self.assertEqual(C4.__parameters__, (T, P))

    def test_var_substitution(self):
        T = TypeVar('T')
        P = ParamSpec('P')
        P2 = ParamSpec('P2')
        C = Concatenate[T, P]
        self.assertEqual(C[int, P2], Concatenate[int, P2])
        self.assertEqual(C[int, [str, float]], (int, str, float))
        self.assertEqual(C[int, []], (int,))
        self.assertEqual(C[int, Concatenate[str, P2]],
                         Concatenate[int, str, P2])
        self.assertEqual(C[int, ...], Concatenate[int, ...])

        C = Concatenate[int, P]
        self.assertEqual(C[P2], Concatenate[int, P2])
        self.assertEqual(C[[str, float]], (int, str, float))
        self.assertEqual(C[str, float], (int, str, float))
        self.assertEqual(C[[]], (int,))
        self.assertEqual(C[Concatenate[str, P2]], Concatenate[int, str, P2])
        self.assertEqual(C[...], Concatenate[int, ...])

class TypeGuardTests(BaseTestCase):
    def test_basics(self):
        TypeGuard[int]  # OK

        def foo(arg) -> TypeGuard[int]: ...
        self.assertEqual(gth(foo), {'return': TypeGuard[int]})

        with self.assertRaises(TypeError):
            TypeGuard[int, str]

    def test_repr(self):
        self.assertEqual(repr(TypeGuard), 'typing.TypeGuard')
        cv = TypeGuard[int]
        self.assertEqual(repr(cv), 'typing.TypeGuard[int]')
        cv = TypeGuard[Employee]
        self.assertEqual(repr(cv), 'typing.TypeGuard[%s.Employee]' % __name__)
        cv = TypeGuard[tuple[int]]
        self.assertEqual(repr(cv), 'typing.TypeGuard[tuple[int]]')

    def test_cannot_subclass(self):
        with self.assertRaisesRegex(TypeError, CANNOT_SUBCLASS_TYPE):
            class C(type(TypeGuard)):
                pass
        with self.assertRaisesRegex(TypeError, CANNOT_SUBCLASS_TYPE):
            class D(type(TypeGuard[int])):
                pass
        with self.assertRaisesRegex(TypeError,
                                    r'Cannot subclass typing\.TypeGuard'):
            class E(TypeGuard):
                pass
        with self.assertRaisesRegex(TypeError,
                                    r'Cannot subclass typing\.TypeGuard\[int\]'):
            class F(TypeGuard[int]):
                pass

    def test_cannot_init(self):
        with self.assertRaises(TypeError):
            TypeGuard()
        with self.assertRaises(TypeError):
            type(TypeGuard)()
        with self.assertRaises(TypeError):
            type(TypeGuard[Optional[int]])()

    def test_no_isinstance(self):
        with self.assertRaises(TypeError):
            isinstance(1, TypeGuard[int])
        with self.assertRaises(TypeError):
            issubclass(int, TypeGuard)


class TypeIsTests(BaseTestCase):
    def test_basics(self):
        TypeIs[int]  # OK

        def foo(arg) -> TypeIs[int]: ...
        self.assertEqual(gth(foo), {'return': TypeIs[int]})

        with self.assertRaises(TypeError):
            TypeIs[int, str]

    def test_repr(self):
        self.assertEqual(repr(TypeIs), 'typing.TypeIs')
        cv = TypeIs[int]
        self.assertEqual(repr(cv), 'typing.TypeIs[int]')
        cv = TypeIs[Employee]
        self.assertEqual(repr(cv), 'typing.TypeIs[%s.Employee]' % __name__)
        cv = TypeIs[tuple[int]]
        self.assertEqual(repr(cv), 'typing.TypeIs[tuple[int]]')

    def test_cannot_subclass(self):
        with self.assertRaisesRegex(TypeError, CANNOT_SUBCLASS_TYPE):
            class C(type(TypeIs)):
                pass
        with self.assertRaisesRegex(TypeError, CANNOT_SUBCLASS_TYPE):
            class D(type(TypeIs[int])):
                pass
        with self.assertRaisesRegex(TypeError,
                                    r'Cannot subclass typing\.TypeIs'):
            class E(TypeIs):
                pass
        with self.assertRaisesRegex(TypeError,
                                    r'Cannot subclass typing\.TypeIs\[int\]'):
            class F(TypeIs[int]):
                pass

    def test_cannot_init(self):
        with self.assertRaises(TypeError):
            TypeIs()
        with self.assertRaises(TypeError):
            type(TypeIs)()
        with self.assertRaises(TypeError):
            type(TypeIs[Optional[int]])()

    def test_no_isinstance(self):
        with self.assertRaises(TypeError):
            isinstance(1, TypeIs[int])
        with self.assertRaises(TypeError):
            issubclass(int, TypeIs)


SpecialAttrsP = typing.ParamSpec('SpecialAttrsP')
SpecialAttrsT = typing.TypeVar('SpecialAttrsT', int, float, complex)


class SpecialAttrsTests(BaseTestCase):

    def test_special_attrs(self):
        cls_to_check = {
            # ABC classes
            typing.AbstractSet: 'AbstractSet',
            typing.AsyncContextManager: 'AsyncContextManager',
            typing.AsyncGenerator: 'AsyncGenerator',
            typing.AsyncIterable: 'AsyncIterable',
            typing.AsyncIterator: 'AsyncIterator',
            typing.Awaitable: 'Awaitable',
            typing.Callable: 'Callable',
            typing.ChainMap: 'ChainMap',
            typing.Collection: 'Collection',
            typing.Container: 'Container',
            typing.ContextManager: 'ContextManager',
            typing.Coroutine: 'Coroutine',
            typing.Counter: 'Counter',
            typing.DefaultDict: 'DefaultDict',
            typing.Deque: 'Deque',
            typing.Dict: 'Dict',
            typing.FrozenSet: 'FrozenSet',
            typing.Generator: 'Generator',
            typing.Hashable: 'Hashable',
            typing.ItemsView: 'ItemsView',
            typing.Iterable: 'Iterable',
            typing.Iterator: 'Iterator',
            typing.KeysView: 'KeysView',
            typing.List: 'List',
            typing.Mapping: 'Mapping',
            typing.MappingView: 'MappingView',
            typing.MutableMapping: 'MutableMapping',
            typing.MutableSequence: 'MutableSequence',
            typing.MutableSet: 'MutableSet',
            typing.OrderedDict: 'OrderedDict',
            typing.Reversible: 'Reversible',
            typing.Sequence: 'Sequence',
            typing.Set: 'Set',
            typing.Sized: 'Sized',
            typing.Tuple: 'Tuple',
            typing.Type: 'Type',
            typing.ValuesView: 'ValuesView',
            # Subscribed ABC classes
            typing.AbstractSet[Any]: 'AbstractSet',
            typing.AsyncContextManager[Any, Any]: 'AsyncContextManager',
            typing.AsyncGenerator[Any, Any]: 'AsyncGenerator',
            typing.AsyncIterable[Any]: 'AsyncIterable',
            typing.AsyncIterator[Any]: 'AsyncIterator',
            typing.Awaitable[Any]: 'Awaitable',
            typing.Callable[[], Any]: 'Callable',
            typing.Callable[..., Any]: 'Callable',
            typing.ChainMap[Any, Any]: 'ChainMap',
            typing.Collection[Any]: 'Collection',
            typing.Container[Any]: 'Container',
            typing.ContextManager[Any, Any]: 'ContextManager',
            typing.Coroutine[Any, Any, Any]: 'Coroutine',
            typing.Counter[Any]: 'Counter',
            typing.DefaultDict[Any, Any]: 'DefaultDict',
            typing.Deque[Any]: 'Deque',
            typing.Dict[Any, Any]: 'Dict',
            typing.FrozenSet[Any]: 'FrozenSet',
            typing.Generator[Any, Any, Any]: 'Generator',
            typing.ItemsView[Any, Any]: 'ItemsView',
            typing.Iterable[Any]: 'Iterable',
            typing.Iterator[Any]: 'Iterator',
            typing.KeysView[Any]: 'KeysView',
            typing.List[Any]: 'List',
            typing.Mapping[Any, Any]: 'Mapping',
            typing.MappingView[Any]: 'MappingView',
            typing.MutableMapping[Any, Any]: 'MutableMapping',
            typing.MutableSequence[Any]: 'MutableSequence',
            typing.MutableSet[Any]: 'MutableSet',
            typing.OrderedDict[Any, Any]: 'OrderedDict',
            typing.Reversible[Any]: 'Reversible',
            typing.Sequence[Any]: 'Sequence',
            typing.Set[Any]: 'Set',
            typing.Tuple[Any]: 'Tuple',
            typing.Tuple[Any, ...]: 'Tuple',
            typing.Type[Any]: 'Type',
            typing.ValuesView[Any]: 'ValuesView',
            # Special Forms
            typing.Annotated: 'Annotated',
            typing.Any: 'Any',
            typing.ClassVar: 'ClassVar',
            typing.Concatenate: 'Concatenate',
            typing.Final: 'Final',
            typing.ForwardRef: 'ForwardRef',
            typing.Literal: 'Literal',
            typing.NewType: 'NewType',
            typing.NoReturn: 'NoReturn',
            typing.Never: 'Never',
            typing.Optional: 'Optional',
            typing.TypeAlias: 'TypeAlias',
            typing.TypeGuard: 'TypeGuard',
            typing.TypeIs: 'TypeIs',
            typing.TypeVar: 'TypeVar',
            typing.Union: 'Union',
            typing.Self: 'Self',
            # Subscribed special forms
            typing.Annotated[Any, "Annotation"]: 'Annotated',
            typing.Annotated[int, 'Annotation']: 'Annotated',
            typing.ClassVar[Any]: 'ClassVar',
            typing.Concatenate[Any, SpecialAttrsP]: 'Concatenate',
            typing.Final[Any]: 'Final',
            typing.Literal[Any]: 'Literal',
            typing.Literal[1, 2]: 'Literal',
            typing.Literal[True, 2]: 'Literal',
            typing.Optional[Any]: 'Optional',
            typing.TypeGuard[Any]: 'TypeGuard',
            typing.TypeIs[Any]: 'TypeIs',
            typing.Union[Any]: 'Any',
            typing.Union[int, float]: 'Union',
            # Incompatible special forms (tested in test_special_attrs2)
            # - typing.ForwardRef('set[Any]')
            # - typing.NewType('TypeName', Any)
            # - typing.ParamSpec('SpecialAttrsP')
            # - typing.TypeVar('T')
        }

        for cls, name in cls_to_check.items():
            with self.subTest(cls=cls):
                self.assertEqual(cls.__name__, name, str(cls))
                self.assertEqual(cls.__qualname__, name, str(cls))
                self.assertEqual(cls.__module__, 'typing', str(cls))
                for proto in range(pickle.HIGHEST_PROTOCOL + 1):
                    s = pickle.dumps(cls, proto)
                    loaded = pickle.loads(s)
                    self.assertIs(cls, loaded)

    TypeName = typing.NewType('SpecialAttrsTests.TypeName', Any)

    def test_special_attrs2(self):
        # Forward refs provide a different introspection API. __name__ and
        # __qualname__ make little sense for forward refs as they can store
        # complex typing expressions.
        fr = typing.ForwardRef('set[Any]')
        self.assertFalse(hasattr(fr, '__name__'))
        self.assertFalse(hasattr(fr, '__qualname__'))
        self.assertEqual(fr.__module__, 'typing')
        # Forward refs are currently unpicklable.
        for proto in range(pickle.HIGHEST_PROTOCOL + 1):
            with self.assertRaises(TypeError):
                pickle.dumps(fr, proto)

        self.assertEqual(SpecialAttrsTests.TypeName.__name__, 'TypeName')
        self.assertEqual(
            SpecialAttrsTests.TypeName.__qualname__,
            'SpecialAttrsTests.TypeName',
        )
        self.assertEqual(
            SpecialAttrsTests.TypeName.__module__,
            __name__,
        )
        # NewTypes are picklable assuming correct qualname information.
        for proto in range(pickle.HIGHEST_PROTOCOL + 1):
            s = pickle.dumps(SpecialAttrsTests.TypeName, proto)
            loaded = pickle.loads(s)
            self.assertIs(SpecialAttrsTests.TypeName, loaded)

        # Type variables don't support non-global instantiation per PEP 484
        # restriction that "The argument to TypeVar() must be a string equal
        # to the variable name to which it is assigned".  Thus, providing
        # __qualname__ is unnecessary.
        self.assertEqual(SpecialAttrsT.__name__, 'SpecialAttrsT')
        self.assertFalse(hasattr(SpecialAttrsT, '__qualname__'))
        self.assertEqual(SpecialAttrsT.__module__, __name__)
        # Module-level type variables are picklable.
        for proto in range(pickle.HIGHEST_PROTOCOL + 1):
            s = pickle.dumps(SpecialAttrsT, proto)
            loaded = pickle.loads(s)
            self.assertIs(SpecialAttrsT, loaded)

        self.assertEqual(SpecialAttrsP.__name__, 'SpecialAttrsP')
        self.assertFalse(hasattr(SpecialAttrsP, '__qualname__'))
        self.assertEqual(SpecialAttrsP.__module__, __name__)
        # Module-level ParamSpecs are picklable.
        for proto in range(pickle.HIGHEST_PROTOCOL + 1):
            s = pickle.dumps(SpecialAttrsP, proto)
            loaded = pickle.loads(s)
            self.assertIs(SpecialAttrsP, loaded)

    def test_genericalias_dir(self):
        class Foo(Generic[T]):
            def bar(self):
                pass
            baz = 3
            __magic__ = 4

        # The class attributes of the original class should be visible even
        # in dir() of the GenericAlias. See bpo-45755.
        dir_items = set(dir(Foo[int]))
        for required_item in [
            'bar', 'baz',
            '__args__', '__parameters__', '__origin__',
        ]:
            with self.subTest(required_item=required_item):
                self.assertIn(required_item, dir_items)
        self.assertNotIn('__magic__', dir_items)


class RevealTypeTests(BaseTestCase):
    def test_reveal_type(self):
        obj = object()
        with captured_stderr() as stderr:
            self.assertIs(obj, reveal_type(obj))
        self.assertEqual(stderr.getvalue(), "Runtime type is 'object'\n")


class DataclassTransformTests(BaseTestCase):
    def test_decorator(self):
        def create_model(*, frozen: bool = False, kw_only: bool = True):
            return lambda cls: cls

        decorated = dataclass_transform(kw_only_default=True, order_default=False)(create_model)

        class CustomerModel:
            id: int

        self.assertIs(decorated, create_model)
        self.assertEqual(
            decorated.__dataclass_transform__,
            {
                "eq_default": True,
                "order_default": False,
                "kw_only_default": True,
                "frozen_default": False,
                "field_specifiers": (),
                "kwargs": {},
            }
        )
        self.assertIs(
            decorated(frozen=True, kw_only=False)(CustomerModel),
            CustomerModel
        )

    def test_base_class(self):
        class ModelBase:
            def __init_subclass__(cls, *, frozen: bool = False): ...

        Decorated = dataclass_transform(
            eq_default=True,
            order_default=True,
            # Arbitrary unrecognized kwargs are accepted at runtime.
            make_everything_awesome=True,
        )(ModelBase)

        class CustomerModel(Decorated, frozen=True):
            id: int

        self.assertIs(Decorated, ModelBase)
        self.assertEqual(
            Decorated.__dataclass_transform__,
            {
                "eq_default": True,
                "order_default": True,
                "kw_only_default": False,
                "frozen_default": False,
                "field_specifiers": (),
                "kwargs": {"make_everything_awesome": True},
            }
        )
        self.assertIsSubclass(CustomerModel, Decorated)

    def test_metaclass(self):
        class Field: ...

        class ModelMeta(type):
            def __new__(
                cls, name, bases, namespace, *, init: bool = True,
            ):
                return super().__new__(cls, name, bases, namespace)

        Decorated = dataclass_transform(
            order_default=True, frozen_default=True, field_specifiers=(Field,)
        )(ModelMeta)

        class ModelBase(metaclass=Decorated): ...

        class CustomerModel(ModelBase, init=False):
            id: int

        self.assertIs(Decorated, ModelMeta)
        self.assertEqual(
            Decorated.__dataclass_transform__,
            {
                "eq_default": True,
                "order_default": True,
                "kw_only_default": False,
                "frozen_default": True,
                "field_specifiers": (Field,),
                "kwargs": {},
            }
        )
        self.assertIsInstance(CustomerModel, Decorated)


class NoDefaultTests(BaseTestCase):
    def test_pickling(self):
        for proto in range(pickle.HIGHEST_PROTOCOL + 1):
            s = pickle.dumps(NoDefault, proto)
            loaded = pickle.loads(s)
            self.assertIs(NoDefault, loaded)

    def test_constructor(self):
        self.assertIs(NoDefault, type(NoDefault)())
        with self.assertRaises(TypeError):
            type(NoDefault)(1)

    def test_repr(self):
        self.assertEqual(repr(NoDefault), 'typing.NoDefault')

    @requires_docstrings
    def test_doc(self):
        self.assertIsInstance(NoDefault.__doc__, str)

    def test_class(self):
        self.assertIs(NoDefault.__class__, type(NoDefault))

    def test_no_call(self):
        with self.assertRaises(TypeError):
            NoDefault()

    def test_no_attributes(self):
        with self.assertRaises(AttributeError):
            NoDefault.foo = 3
        with self.assertRaises(AttributeError):
            NoDefault.foo

        # TypeError is consistent with the behavior of NoneType
        with self.assertRaises(TypeError):
            type(NoDefault).foo = 3
        with self.assertRaises(AttributeError):
            type(NoDefault).foo


class AllTests(BaseTestCase):
    """Tests for __all__."""

    def test_all(self):
        from typing import __all__ as a
        # Just spot-check the first and last of every category.
        self.assertIn('AbstractSet', a)
        self.assertIn('ValuesView', a)
        self.assertIn('cast', a)
        self.assertIn('overload', a)
        # Context managers.
        self.assertIn('ContextManager', a)
        self.assertIn('AsyncContextManager', a)
        # Check that former namespaces io and re are not exported.
        self.assertNotIn('io', a)
        self.assertNotIn('re', a)
        # Spot-check that stdlib modules aren't exported.
        self.assertNotIn('os', a)
        self.assertNotIn('sys', a)
        # Check that Text is defined.
        self.assertIn('Text', a)
        # Check previously missing classes.
        self.assertIn('SupportsBytes', a)
        self.assertIn('SupportsComplex', a)

    def test_all_exported_names(self):
        # ensure all dynamically created objects are actualised
        for name in typing.__all__:
            getattr(typing, name)

        actual_all = set(typing.__all__)
        computed_all = {
            k for k, v in vars(typing).items()
            # explicitly exported, not a thing with __module__
            if k in actual_all or (
                # avoid private names
                not k.startswith('_') and
                # there's a few types and metaclasses that aren't exported
                not k.endswith(('Meta', '_contra', '_co')) and
                not k.upper() == k and
                # but export all things that have __module__ == 'typing'
                getattr(v, '__module__', None) == typing.__name__
            )
        }
        self.assertSetEqual(computed_all, actual_all)


class TypeIterationTests(BaseTestCase):
    _UNITERABLE_TYPES = (
        Any,
        Union,
        Union[str, int],
        Union[str, T],
        List,
        Tuple,
        Callable,
        Callable[..., T],
        Callable[[T], str],
        Annotated,
        Annotated[T, ''],
    )

    def test_cannot_iterate(self):
        expected_error_regex = "object is not iterable"
        for test_type in self._UNITERABLE_TYPES:
            with self.subTest(type=test_type):
                with self.assertRaisesRegex(TypeError, expected_error_regex):
                    iter(test_type)
                with self.assertRaisesRegex(TypeError, expected_error_regex):
                    list(test_type)
                with self.assertRaisesRegex(TypeError, expected_error_regex):
                    for _ in test_type:
                        pass

    def test_is_not_instance_of_iterable(self):
        for type_to_test in self._UNITERABLE_TYPES:
            self.assertNotIsInstance(type_to_test, collections.abc.Iterable)


def load_tests(loader, tests, pattern):
    import doctest
    tests.addTests(doctest.DocTestSuite(typing))
    return tests


if __name__ == '__main__':
    main()