check-python312.test

[case testPEP695TypeAliasBasic]
type MyInt = int

def f(x: MyInt) -> MyInt:
    return reveal_type(x)  # N: Revealed type is "builtins.int"

type MyList[T] = list[T]

def g(x: MyList[int]) -> MyList[int]:
    return reveal_type(x)  # N: Revealed type is "builtins.list[builtins.int]"

type MyInt2 = int

def h(x: MyInt2) -> MyInt2:
    return reveal_type(x)  # N: Revealed type is "builtins.int"

[case testPEP695Class]
class MyGen[T]:
    def __init__(self, x: T) -> None:
        self.x = x

def f(x: MyGen[int]):
    reveal_type(x.x)  # N: Revealed type is "builtins.int"

[case testPEP695Function]
def f[T](x: T) -> T:
    return reveal_type(x)  # N: Revealed type is "T`-1"

reveal_type(f(1))  # N: Revealed type is "builtins.int"

async def g[T](x: T) -> T:
    return reveal_type(x)  # N: Revealed type is "T`-1"

reveal_type(g(1))  # E: Value of type "Coroutine[Any, Any, int]" must be used \
                   # N: Are you missing an await? \
                   # N: Revealed type is "typing.Coroutine[Any, Any, builtins.int]"

[case testPEP695TypeVarBasic]
from typing import Callable
type Alias1[T: int] = list[T]
type Alias2[**P] = Callable[P, int]
type Alias3[*Ts] = tuple[*Ts]

class Cls1[T: int]: ...
class Cls2[**P]: ...
class Cls3[*Ts]: ...

def func1[T: int](x: T) -> T: ...
def func2[**P](x: Callable[P, int]) -> Callable[P, str]: ...
def func3[*Ts](x: tuple[*Ts]) -> tuple[int, *Ts]: ...
[builtins fixtures/tuple.pyi]

[case testPEP695TypeAliasType]
from typing import Callable, TypeAliasType, TypeVar, TypeVarTuple

T = TypeVar("T")
Ts = TypeVarTuple("Ts")

TestType = TypeAliasType("TestType", int | str)
x: TestType = 42
y: TestType = 'a'
z: TestType = object()  # E: Incompatible types in assignment (expression has type "object", variable has type "Union[int, str]")

BadAlias1 = TypeAliasType("BadAlias1", tuple[*Ts])  # E: TypeVarTuple "Ts" is not included in type_params
ba1: BadAlias1[int]  # E: Bad number of arguments for type alias, expected 0, given 1
reveal_type(ba1)  # N: Revealed type is "builtins.tuple[Any, ...]"

BadAlias2 = TypeAliasType("BadAlias2", Callable[[*Ts], str])  # E: TypeVarTuple "Ts" is not included in type_params
ba2: BadAlias2[int]  # E: Bad number of arguments for type alias, expected 0, given 1
reveal_type(ba2)  # N: Revealed type is "def (*Any) -> builtins.str"

[builtins fixtures/tuple.pyi]
[typing fixtures/typing-full.pyi]

[case testPEP695IncompleteFeatureIsAcceptedButHasNoEffect]
# mypy: enable-incomplete-feature=NewGenericSyntax
def f[T](x: T) -> T:
    return x
reveal_type(f(1))  # N: Revealed type is "builtins.int"

[case testPEP695GenericFunctionSyntax]
def ident[TV](x: TV) -> TV:
    y: TV = x
    y = 1  # E: Incompatible types in assignment (expression has type "int", variable has type "TV")
    return x

reveal_type(ident(1))  # N: Revealed type is "builtins.int"
reveal_type(ident('x'))  # N: Revealed type is "builtins.str"

a: TV  # E: Name "TV" is not defined

def tup[T, S](x: T, y: S) -> tuple[T, S]:
    reveal_type((x, y))  # N: Revealed type is "tuple[T`-1, S`-2]"
    return (x, y)

reveal_type(tup(1, 'x'))  # N: Revealed type is "tuple[builtins.int, builtins.str]"
[builtins fixtures/tuple.pyi]

[case testPEP695GenericClassSyntax]
class C[T]:
    x: T

    def __init__(self, x: T) -> None:
        self.x = x

    def ident(self, x: T) -> T:
        y: T = x
        if int():
            return self.x
        else:
            return y

reveal_type(C("x"))  # N: Revealed type is "__main__.C[builtins.str]"
c: C[int] = C(1)
reveal_type(c.x)  # N: Revealed type is "builtins.int"
reveal_type(c.ident(1))  # N: Revealed type is "builtins.int"

[case testPEP695GenericMethodInGenericClass]
class C[T]:
    def m[S](self, x: S) -> T | S: ...

a: C[int] = C[object]()  # E: Incompatible types in assignment (expression has type "C[object]", variable has type "C[int]")
b: C[object] = C[int]()

reveal_type(C[str]().m(1))  # N: Revealed type is "Union[builtins.str, builtins.int]"

[case testPEP695InferVarianceSimpleFromMethod]
class Invariant[T]:
    def f(self, x: T) -> None:
        pass

    def g(self) -> T | None:
        return None

a: Invariant[object]
b: Invariant[int]
if int():
    a = b  # E: Incompatible types in assignment (expression has type "Invariant[int]", variable has type "Invariant[object]")
if int():
    b = a  # E: Incompatible types in assignment (expression has type "Invariant[object]", variable has type "Invariant[int]")

class Covariant[T]:
    def g(self) -> T | None:
        return None

c: Covariant[object]
d: Covariant[int]
if int():
    c = d
if int():
    d = c  # E: Incompatible types in assignment (expression has type "Covariant[object]", variable has type "Covariant[int]")

class Contravariant[T]:
    def f(self, x: T) -> None:
        pass

e: Contravariant[object]
f: Contravariant[int]
if int():
    e = f  # E: Incompatible types in assignment (expression has type "Contravariant[int]", variable has type "Contravariant[object]")
if int():
    f = e

[case testPEP695InferVarianceSimpleFromAttribute]
class Invariant1[T]:
    def __init__(self, x: T) -> None:
        self.x = x

a: Invariant1[object]
b: Invariant1[int]
if int():
    a = b  # E: Incompatible types in assignment (expression has type "Invariant1[int]", variable has type "Invariant1[object]")
if int():
    b = a  # E: Incompatible types in assignment (expression has type "Invariant1[object]", variable has type "Invariant1[int]")

class Invariant2[T]:
    def __init__(self) -> None:
        self.x: list[T] = []

a2: Invariant2[object]
b2: Invariant2[int]
if int():
    a2 = b2  # E: Incompatible types in assignment (expression has type "Invariant2[int]", variable has type "Invariant2[object]")
if int():
    b2 = a2  # E: Incompatible types in assignment (expression has type "Invariant2[object]", variable has type "Invariant2[int]")

class Invariant3[T]:
    def __init__(self) -> None:
        self.x: T | None = None

a3: Invariant3[object]
b3: Invariant3[int]
if int():
    a3 = b3  # E: Incompatible types in assignment (expression has type "Invariant3[int]", variable has type "Invariant3[object]")
if int():
    b3 = a3  # E: Incompatible types in assignment (expression has type "Invariant3[object]", variable has type "Invariant3[int]")

[case testPEP695InferVarianceRecursive]
class Invariant[T]:
    def f(self, x: Invariant[T]) -> Invariant[T]:
        return x

class Covariant[T]:
    def f(self) -> Covariant[T]:
        return self

class Contravariant[T]:
    def f(self, x: Contravariant[T]) -> None:
        pass

a: Invariant[object]
b: Invariant[int]
if int():
    a = b  # E: Incompatible types in assignment (expression has type "Invariant[int]", variable has type "Invariant[object]")
if int():
    b = a

c: Covariant[object]
d: Covariant[int]
if int():
    c = d
if int():
    d = c  # E: Incompatible types in assignment (expression has type "Covariant[object]", variable has type "Covariant[int]")

e: Contravariant[object]
f: Contravariant[int]
if int():
    e = f  # E: Incompatible types in assignment (expression has type "Contravariant[int]", variable has type "Contravariant[object]")
if int():
    f = e

[case testPEP695InferVarianceInFrozenDataclass]
from dataclasses import dataclass

@dataclass(frozen=True)
class Covariant[T]:
    x: T

cov1: Covariant[float] = Covariant[int](1)
cov2: Covariant[int] = Covariant[float](1)  # E: Incompatible types in assignment (expression has type "Covariant[float]", variable has type "Covariant[int]")

@dataclass(frozen=True)
class Invariant[T]:
    x: list[T]

inv1: Invariant[float] = Invariant[int]([1])  # E: Incompatible types in assignment (expression has type "Invariant[int]", variable has type "Invariant[float]")
inv2: Invariant[int] = Invariant[float]([1])  # E: Incompatible types in assignment (expression has type "Invariant[float]", variable has type "Invariant[int]")
[builtins fixtures/tuple.pyi]
[typing fixtures/typing-full.pyi]

[case testPEP695InferVarianceCalculateOnDemand]
class Covariant[T]:
    def __init__(self) -> None:
        self.x = [1]

    def f(self) -> None:
        c = Covariant[int]()
        # We need to know that T is covariant here
        self.g(c)
        c2 = Covariant[object]()
        self.h(c2)  # E: Argument 1 to "h" of "Covariant" has incompatible type "Covariant[object]"; expected "Covariant[int]"

    def g(self, x: Covariant[object]) -> None: pass
    def h(self, x: Covariant[int]) -> None: pass

[case testPEP695InferVarianceNotReadyWhenNeeded]
class Covariant[T]:
    def f(self) -> None:
        c = Covariant[int]()
        # We need to know that T is covariant here
        self.g(c)
        c2 = Covariant[object]()
        self.h(c2)  # E: Argument 1 to "h" of "Covariant" has incompatible type "Covariant[object]"; expected "Covariant[int]"

    def g(self, x: Covariant[object]) -> None: pass
    def h(self, x: Covariant[int]) -> None: pass

    def __init__(self) -> None:
        self.x = [1]

class Invariant[T]:
    def f(self) -> None:
        c = Invariant(1)
        # We need to know that T is invariant here, and for this we need the type
        # of self.x, which won't be available on the first type checking pass,
        # since __init__ is defined later in the file. In this case we fall back
        # covariance.
        self.g(c)
        c2 = Invariant(object())
        self.h(c2)  # E: Argument 1 to "h" of "Invariant" has incompatible type "Invariant[object]"; expected "Invariant[int]"

    def g(self, x: Invariant[object]) -> None: pass
    def h(self, x: Invariant[int]) -> None: pass

    def __init__(self, x: T) -> None:
        self.x = x

# Now we should have the variance correct.
a: Invariant[object]
b: Invariant[int]
if int():
    a = b  # E: Incompatible types in assignment (expression has type "Invariant[int]", variable has type "Invariant[object]")
if int():
    b = a  # E: Incompatible types in assignment (expression has type "Invariant[object]", variable has type "Invariant[int]")

[case testPEP695InferVarianceNotReadyForJoin]
class Invariant[T]:
    def f(self) -> None:
        # Assume covariance if variance us not ready
        reveal_type([Invariant(1), Invariant(object())]) \
            # N: Revealed type is "builtins.list[__main__.Invariant[builtins.object]]"

    def __init__(self, x: T) -> None:
        self.x = x

reveal_type([Invariant(1), Invariant(object())])   # N: Revealed type is "builtins.list[builtins.object]"

[case testPEP695InferVarianceNotReadyForMeet]
from typing import TypeVar, Callable

S = TypeVar("S")
def c(a: Callable[[S], None], b: Callable[[S], None]) -> S: ...

def a1(x: Invariant[int]) -> None: pass
def a2(x: Invariant[object]) -> None: pass

class Invariant[T]:
    def f(self) -> None:
        reveal_type(c(a1, a2))  # N: Revealed type is "__main__.Invariant[builtins.int]"

    def __init__(self, x: T) -> None:
        self.x = x

reveal_type(c(a1, a2))  # N: Revealed type is "Never"

[case testPEP695InferVarianceUnderscorePrefix]
class Covariant1[T]:
    def __init__(self, x: T) -> None:
        self._x = x

    @property
    def x(self) -> T:
        return self._x

co1_1: Covariant1[float] = Covariant1[int](1)
co1_2: Covariant1[int] = Covariant1[float](1)  # E: Incompatible types in assignment (expression has type "Covariant1[float]", variable has type "Covariant1[int]")

class Covariant2[T]:
    def __init__(self, x: T) -> None:
        self.__foo_bar = x

    @property
    def x(self) -> T:
        return self.__foo_bar

co2_1: Covariant2[float] = Covariant2[int](1)
co2_2: Covariant2[int] = Covariant2[float](1)  # E: Incompatible types in assignment (expression has type "Covariant2[float]", variable has type "Covariant2[int]")

class Invariant1[T]:
    def __init__(self, x: T) -> None:
        self._x = x

    # Methods behave differently from attributes
    def _f(self, x: T) -> None: ...

    @property
    def x(self) -> T:
        return self._x

inv1_1: Invariant1[float] = Invariant1[int](1)  # E: Incompatible types in assignment (expression has type "Invariant1[int]", variable has type "Invariant1[float]")
inv1_2: Invariant1[int] = Invariant1[float](1)  # E: Incompatible types in assignment (expression has type "Invariant1[float]", variable has type "Invariant1[int]")

class Invariant2[T]:
    def __init__(self, x: T) -> None:
        # Dunders are special
        self.__x__ = x

    @property
    def x(self) -> T:
        return self.__x__

inv2_1: Invariant2[float] = Invariant2[int](1)  # E: Incompatible types in assignment (expression has type "Invariant2[int]", variable has type "Invariant2[float]")
inv2_2: Invariant2[int] = Invariant2[float](1)  # E: Incompatible types in assignment (expression has type "Invariant2[float]", variable has type "Invariant2[int]")

class Invariant3[T]:
    def __init__(self, x: T) -> None:
        self._x = Invariant1(x)

    @property
    def x(self) -> T:
        return self._x._x

inv3_1: Invariant3[float] = Invariant3[int](1)  # E: Incompatible types in assignment (expression has type "Invariant3[int]", variable has type "Invariant3[float]")
inv3_2: Invariant3[int] = Invariant3[float](1)  # E: Incompatible types in assignment (expression has type "Invariant3[float]", variable has type "Invariant3[int]")
[builtins fixtures/property.pyi]

[case testPEP695InferVarianceWithInheritedSelf]
from typing import overload, Self, TypeVar, Generic

T = TypeVar("T")
S = TypeVar("S")

class C(Generic[T]):
    def f(self, x: T) -> Self: ...
    def g(self) -> T: ...

class D[T1, T2](C[T1]):
    def m(self, x: T2) -> None: ...

a1: D[int, int] = D[int, object]()
a2: D[int, object] = D[int, int]()  # E: Incompatible types in assignment (expression has type "D[int, int]", variable has type "D[int, object]")
a3: D[int, int] = D[object, object]()  # E: Incompatible types in assignment (expression has type "D[object, object]", variable has type "D[int, int]")
a4: D[object, int] = D[int, object]()  # E: Incompatible types in assignment (expression has type "D[int, object]", variable has type "D[object, int]")

[case testPEP695InferVarianceWithReturnSelf]
from typing import Self, overload

class Cov[T]:
    def f(self) -> Self: ...

a1: Cov[int] = Cov[float]()  # E: Incompatible types in assignment (expression has type "Cov[float]", variable has type "Cov[int]")
a2: Cov[float] = Cov[int]()

class Contra[T]:
    def f(self) -> Self: ...
    def g(self, x: T) -> None: ...

b1: Contra[int] = Contra[float]()
b2: Contra[float] = Contra[int]()  # E: Incompatible types in assignment (expression has type "Contra[int]", variable has type "Contra[float]")

class Cov2[T]:
    @overload
    def f(self, x): ...
    @overload
    def f(self) -> Self: ...
    def f(self, x=None): ...

c1: Cov2[int] = Cov2[float]()  # E: Incompatible types in assignment (expression has type "Cov2[float]", variable has type "Cov2[int]")
c2: Cov2[float] = Cov2[int]()

class Contra2[T]:
    @overload
    def f(self, x): ...
    @overload
    def f(self) -> Self: ...
    def f(self, x=None): ...

    def g(self, x: T) -> None: ...

d1: Contra2[int] = Contra2[float]()
d2: Contra2[float] = Contra2[int]()  # E: Incompatible types in assignment (expression has type "Contra2[int]", variable has type "Contra2[float]")

[case testPEP695InheritInvariant]
class Invariant[T]:
    x: T

class Subclass[T](Invariant[T]):
    pass

x: Invariant[int]
y: Invariant[object]
if int():
    x = y  # E: Incompatible types in assignment (expression has type "Invariant[object]", variable has type "Invariant[int]")
if int():
    y = x  # E: Incompatible types in assignment (expression has type "Invariant[int]", variable has type "Invariant[object]")

a: Subclass[int]
b: Subclass[object]
if int():
    a = b  # E: Incompatible types in assignment (expression has type "Subclass[object]", variable has type "Subclass[int]")
if int():
    b = a  # E: Incompatible types in assignment (expression has type "Subclass[int]", variable has type "Subclass[object]")

[case testPEP695InheritanceMakesInvariant]
class Covariant[T]:
    def f(self) -> T:
        ...

class Subclass[T](Covariant[list[T]]):
    pass

x: Covariant[int] = Covariant[object]()  # E: Incompatible types in assignment (expression has type "Covariant[object]", variable has type "Covariant[int]")
y: Covariant[object] = Covariant[int]()

a: Subclass[int] = Subclass[object]()  # E: Incompatible types in assignment (expression has type "Subclass[object]", variable has type "Subclass[int]")
b: Subclass[object] = Subclass[int]()  # E: Incompatible types in assignment (expression has type "Subclass[int]", variable has type "Subclass[object]")

[case testPEP695InheritCoOrContravariant]
class Contravariant[T]:
    def f(self, x: T) -> None: pass

class CovSubclass[T](Contravariant[T]):
    pass

a: CovSubclass[int] = CovSubclass[object]()
b: CovSubclass[object] = CovSubclass[int]()  # E: Incompatible types in assignment (expression has type "CovSubclass[int]", variable has type "CovSubclass[object]")

class Covariant[T]:
    def f(self) -> T: ...

class CoSubclass[T](Covariant[T]):
    pass

c: CoSubclass[int] = CoSubclass[object]()  # E: Incompatible types in assignment (expression has type "CoSubclass[object]", variable has type "CoSubclass[int]")
d: CoSubclass[object] = CoSubclass[int]()

class InvSubclass[T](Covariant[T]):
    def g(self, x: T) -> None: pass

e: InvSubclass[int] = InvSubclass[object]()  # E: Incompatible types in assignment (expression has type "InvSubclass[object]", variable has type "InvSubclass[int]")
f: InvSubclass[object] = InvSubclass[int]()  # E: Incompatible types in assignment (expression has type "InvSubclass[int]", variable has type "InvSubclass[object]")

[case testPEP695FinalAttribute]
from typing import Final

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

a: C[int] = C[object](1)  # E: Incompatible types in assignment (expression has type "C[object]", variable has type "C[int]")
b: C[object] = C[int](1)

[case testPEP695TwoTypeVariables]
class C[T, S]:
    def f(self, x: T) -> None: ...
    def g(self) -> S: ...

a: C[int, int] = C[object, int]()
b: C[object, int] = C[int, int]()  # E: Incompatible types in assignment (expression has type "C[int, int]", variable has type "C[object, int]")
c: C[int, int] = C[int, object]()  # E: Incompatible types in assignment (expression has type "C[int, object]", variable has type "C[int, int]")
d: C[int, object] = C[int, int]()

[case testPEP695Properties]
class R[T]:
    @property
    def p(self) -> T: ...

class RW[T]:
    @property
    def p(self) -> T: ...
    @p.setter
    def p(self, x: T) -> None: ...

a: R[int] = R[object]()  # E: Incompatible types in assignment (expression has type "R[object]", variable has type "R[int]")
b: R[object] = R[int]()
c: RW[int] = RW[object]()  # E: Incompatible types in assignment (expression has type "RW[object]", variable has type "RW[int]")
d: RW[object] = RW[int]()  # E: Incompatible types in assignment (expression has type "RW[int]", variable has type "RW[object]")
[builtins fixtures/property.pyi]

[case testPEP695Protocol]
from typing import Protocol

class PContra[T](Protocol):
    def f(self, x: T) -> None: ...

PContra()  # E: Cannot instantiate protocol class "PContra"
a: PContra[int]
b: PContra[object]
if int():
    a = b
if int():
    b = a  # E: Incompatible types in assignment (expression has type "PContra[int]", variable has type "PContra[object]")

class PCov[T](Protocol):
    def f(self) -> T: ...

PCov()  # E: Cannot instantiate protocol class "PCov"
c: PCov[int]
d: PCov[object]
if int():
    c = d  # E: Incompatible types in assignment (expression has type "PCov[object]", variable has type "PCov[int]")
if int():
    d = c

class PInv[T](Protocol):
    def f(self, x: T) -> T: ...

PInv()  # E: Cannot instantiate protocol class "PInv"
e: PInv[int]
f: PInv[object]
if int():
    e = f  # E: Incompatible types in assignment (expression has type "PInv[object]", variable has type "PInv[int]")
if int():
    f = e  # E: Incompatible types in assignment (expression has type "PInv[int]", variable has type "PInv[object]")

[case testPEP695TypeAlias]
class C[T]: pass
class D[T, S]: pass

type A[S] = C[S]

a: A[int]
reveal_type(a)  # N: Revealed type is "__main__.C[builtins.int]"

type A2[T] = C[C[T]]
a2: A2[str]
reveal_type(a2)  # N: Revealed type is "__main__.C[__main__.C[builtins.str]]"

type A3[T, S] = D[S, C[T]]
a3: A3[int, str]
reveal_type(a3)  # N: Revealed type is "__main__.D[builtins.str, __main__.C[builtins.int]]"

type A4 = int | str
a4: A4
reveal_type(a4)  # N: Revealed type is "Union[builtins.int, builtins.str]"
[builtins fixtures/type.pyi]

[case testPEP695TypeAliasNotValidAsBaseClass]
from typing import TypeAlias

import m

type A1 = int
class Bad1(A1):  # E: Type alias defined using "type" statement not valid as base class
    pass

type A2[T] = list[T]
class Bad2(A2[int]):  # E: Type alias defined using "type" statement not valid as base class
    pass

class Bad3(m.A1):  # E: Type alias defined using "type" statement not valid as base class
    pass

class Bad4(m.A2[int]):  # E: Type alias defined using "type" statement not valid as base class
    pass

B1 = int
B2 = list
B3: TypeAlias = int
class Good1(B1): pass
class Good2(B2[int]): pass
class Good3(list[A1]): pass
class Good4(list[A2[int]]): pass
class Good5(B3): pass

[file m.py]
type A1 = str
type A2[T] = list[T]
[typing fixtures/typing-medium.pyi]

[case testPEP695TypeAliasWithUnusedTypeParams]
type A[T] = int
a: A[str]
reveal_type(a)  # N: Revealed type is "builtins.int"

[case testPEP695TypeAliasForwardReference1]
type A[T] = C[T]

a: A[int]
reveal_type(a)  # N: Revealed type is "__main__.C[builtins.int]"

class C[T]: pass

[case testPEP695TypeAliasForwardReference2]
type X = C
type A = X

a: A
reveal_type(a)  # N: Revealed type is "__main__.C"

class C: pass
[builtins fixtures/tuple.pyi]
[typing fixtures/typing-full.pyi]

[case testPEP695TypeAliasForwardReference3]
type X = D
type A = C[X]

a: A
reveal_type(a)  # N: Revealed type is "__main__.C[__main__.D]"

class C[T]: pass
class D: pass

[case testPEP695TypeAliasForwardReference4]
type A = C

class D(A):  # E: Type alias defined using "type" statement not valid as base class
    pass

class C: pass

x: C = D()
y: D = C()  # E: Incompatible types in assignment (expression has type "C", variable has type "D")

[case testPEP695TypeAliasForwardReference5]
type A = str
type B[T] = C[T]
class C[T]: pass
a: A
b: B[int]
c: C[str]
reveal_type(a)  # N: Revealed type is "builtins.str"
reveal_type(b)  # N: Revealed type is "__main__.C[builtins.int]"
reveal_type(c)  # N: Revealed type is "__main__.C[builtins.str]"

[case testPEP695TypeAliasWithUndefineName]
type A[T] = XXX  # E: Name "XXX" is not defined
a: A[int]
reveal_type(a)  # N: Revealed type is "Any"

[case testPEP695TypeAliasInvalidType]
type A = int | 1  # E: Invalid type: try using Literal[1] instead?

a: A
reveal_type(a)  # N: Revealed type is "Union[builtins.int, Any]"
type B = int + str  # E: Invalid type alias: expression is not a valid type
b: B
reveal_type(b)  # N: Revealed type is "Any"
[builtins fixtures/type.pyi]

[case testPEP695TypeAliasBoundForwardReference]
type B[T: Foo] = list[T]
class Foo: pass

[case testPEP695UpperBound]
class D:
    x: int
class E(D): pass

class C[T: D]: pass

a: C[D]
b: C[E]
reveal_type(a)  # N: Revealed type is "__main__.C[__main__.D]"
reveal_type(b)  # N: Revealed type is "__main__.C[__main__.E]"

c: C[int]  # E: Type argument "int" of "C" must be a subtype of "D"

def f[T: D](a: T) -> T:
    reveal_type(a.x)  # N: Revealed type is "builtins.int"
    return a

reveal_type(f(D()))  # N: Revealed type is "__main__.D"
reveal_type(f(E()))  # N: Revealed type is "__main__.E"
f(1)  # E: Value of type variable "T" of "f" cannot be "int"

[case testPEP695UpperBoundForwardReference1]
class C[T: D]: pass

a: C[D]
b: C[E]
reveal_type(a)  # N: Revealed type is "__main__.C[__main__.D]"
reveal_type(b)  # N: Revealed type is "__main__.C[__main__.E]"

c: C[int]  # E: Type argument "int" of "C" must be a subtype of "D"

class D: pass
class E(D): pass

[case testPEP695UpperBoundForwardReference2]
type A = D
class C[T: A]: pass

class D: pass
class E(D): pass

a: C[D]
b: C[E]
reveal_type(a)  # N: Revealed type is "__main__.C[__main__.D]"
reveal_type(b)  # N: Revealed type is "__main__.C[__main__.E]"

c: C[int]  # E: Type argument "int" of "C" must be a subtype of "D"

[case testPEP695UpperBoundForwardReference3]
class D[T]: pass
class E[T](D[T]): pass

type A = D[X]

class C[T: A]: pass

class X: pass

a: C[D[X]]
b: C[E[X]]
reveal_type(a)  # N: Revealed type is "__main__.C[__main__.D[__main__.X]]"
reveal_type(b)  # N: Revealed type is "__main__.C[__main__.E[__main__.X]]"

c: C[D[int]]  # E: Type argument "D[int]" of "C" must be a subtype of "D[X]"

[case testPEP695UpperBoundForwardReference4]
def f[T: D](a: T) -> T:
    reveal_type(a.x)  # N: Revealed type is "builtins.int"
    return a

class D:
    x: int
class E(D): pass

reveal_type(f(D()))  # N: Revealed type is "__main__.D"
reveal_type(f(E()))  # N: Revealed type is "__main__.E"
f(1)  # E: Value of type variable "T" of "f" cannot be "int"

[case testPEP695UpperBoundUndefinedName]
class C[T: XX]:  # E: Name "XX" is not defined
    pass

a: C[int]

def f[T: YY](x: T) -> T:  # E: Name "YY" is not defined
    return x
reveal_type(f)  # N: Revealed type is "def [T <: Any] (x: T`-1) -> T`-1"

[case testPEP695UpperBoundWithMultipleParams]
class C[T, S: int]: pass
class D[A: int, B]: pass

def f[T: int, S: int | str](x: T, y: S) -> T | S:
    return x

C[str, int]()
C[str, str]()  # E: Value of type variable "S" of "C" cannot be "str"
D[int, str]()
D[str, str]()  # E: Value of type variable "A" of "D" cannot be "str"
f(1, 1)
u: int | str
f(1, u)
f('x', None)  # E: Value of type variable "T" of "f" cannot be "str" \
              # E: Value of type variable "S" of "f" cannot be "None"

[case testPEP695InferVarianceOfTupleType]
class Cov[T](tuple[int, str]):
    def f(self) -> T: pass

class Cov2[T](tuple[T, T]):
    pass

class Contra[T](tuple[int, str]):
    def f(self, x: T) -> None: pass

a: Cov[object] = Cov[int]()
b: Cov[int] = Cov[object]()  # E: Incompatible types in assignment (expression has type "Cov[object]", variable has type "Cov[int]")

c: Cov2[object] = Cov2[int]()
d: Cov2[int] = Cov2[object]()  # E: Incompatible types in assignment (expression has type "Cov2[object]", variable has type "Cov2[int]")

e: Contra[int] = Contra[object]()
f: Contra[object] = Contra[int]()  # E: Incompatible types in assignment (expression has type "Contra[int]", variable has type "Contra[object]")
[builtins fixtures/tuple-simple.pyi]

[case testPEP695ValueRestriction]
def f[T: (int, str)](x: T) -> T:
    reveal_type(x)  # N: Revealed type is "builtins.int" \
                    # N: Revealed type is "builtins.str"
    return x

reveal_type(f(1))  # N: Revealed type is "builtins.int"
reveal_type(f('x'))  # N: Revealed type is "builtins.str"
f(None)  # E: Value of type variable "T" of "f" cannot be "None"

class C[T: (object, None)]: pass

a: C[object]
b: C[None]
c: C[int]  # E: Value of type variable "T" of "C" cannot be "int"

[case testPEP695ValueRestrictionForwardReference]
class C[T: (int, D)]:
    def __init__(self, x: T) -> None:
        a = x
        if int():
            a = 'x'  # E: Incompatible types in assignment (expression has type "str", variable has type "int") \
                     # E: Incompatible types in assignment (expression has type "str", variable has type "D")
        self.x: T = x

reveal_type(C(1).x)  # N: Revealed type is "builtins.int"
C(None)  # E: Value of type variable "T" of "C" cannot be "None"

class D: pass

C(D())

[case testPEP695ValueRestrictionUndefinedName]
class C[T: (int, XX)]:  # E: Name "XX" is not defined
    pass

def f[S: (int, YY)](x: S) -> S:  # E: Name "YY" is not defined
    return x

[case testPEP695ParamSpec]
from typing import Callable

def g[**P](f: Callable[P, None], *args: P.args, **kwargs: P.kwargs) -> None:
    f(*args, **kwargs)
    f(1, *args, **kwargs)  # E: Argument 1 has incompatible type "int"; expected "P.args"

def h(x: int, y: str) -> None: pass

g(h, 1, y='x')
g(h, 1, x=1)  # E: "g" gets multiple values for keyword argument "x" \
              # E: Missing positional argument "y" in call to "g"

class C[**P, T]:
    def m(self, *args: P.args, **kwargs: P.kwargs) -> T: ...

a: C[[int, str], None]
reveal_type(a)  # N: Revealed type is "__main__.C[[builtins.int, builtins.str], None]"
reveal_type(a.m)  # N: Revealed type is "def (builtins.int, builtins.str)"
[builtins fixtures/tuple.pyi]

[case testPEP695ParamSpecTypeAlias]
from typing import Callable

type C[**P] = Callable[P, int]

f: C[[str, int | None]]
reveal_type(f)  # N: Revealed type is "def (builtins.str, Union[builtins.int, None]) -> builtins.int"
[builtins fixtures/tuple.pyi]
[typing fixtures/typing-full.pyi]

[case testPEP695TypeVarTuple]
def f[*Ts](t: tuple[*Ts]) -> tuple[*Ts]:
    reveal_type(t)  # N: Revealed type is "tuple[Unpack[Ts`-1]]"
    return t

reveal_type(f((1, 'x')))  # N: Revealed type is "tuple[Literal[1]?, Literal['x']?]"
a: tuple[int, ...]
reveal_type(f(a))  # N: Revealed type is "builtins.tuple[builtins.int, ...]"

class C[T, *Ts]:
    pass

b: C[int, str, None]
reveal_type(b)  # N: Revealed type is "__main__.C[builtins.int, builtins.str, None]"
c: C[str]
reveal_type(c)  # N: Revealed type is "__main__.C[builtins.str]"
b = c  # E: Incompatible types in assignment (expression has type "C[str]", variable has type "C[int, str, None]")
[builtins fixtures/tuple.pyi]

[case testPEP695TypeVarTupleAlias]
from typing import Callable

type C[*Ts] = tuple[*Ts, int]

a: C[str, None]
reveal_type(a)  # N: Revealed type is "tuple[builtins.str, None, builtins.int]"
[builtins fixtures/tuple.pyi]

[case testPEP695IncrementalFunction]
import a

[file a.py]
import b

[file a.py.2]
import b
reveal_type(b.f(1))
reveal_type(b.g(1, 'x'))
b.g('x', 'x')
b.g(1, 2)

[file b.py]
def f[T](x: T) -> T:
    return x

def g[T: int, S: (str, None)](x: T, y: S) -> T | S:
    return x

[out2]
tmp/a.py:2: note: Revealed type is "builtins.int"
tmp/a.py:3: note: Revealed type is "Union[builtins.int, builtins.str]"
tmp/a.py:4: error: Value of type variable "T" of "g" cannot be "str"
tmp/a.py:5: error: Value of type variable "S" of "g" cannot be "int"

[case testPEP695IncrementalClass]
import a

[file a.py]
import b

[file a.py.2]
from b import C, D
x: C[int]
reveal_type(x)

class N(int): pass
class SS(str): pass

y1: D[int, str]
y2: D[N, str]
y3: D[int, None]
y4: D[int, None]
y5: D[int, SS]  # Error
y6: D[object, str]  # Error

[file b.py]
class C[T]: pass

class D[T: int, S: (str, None)]:
    pass

[out2]
tmp/a.py:3: note: Revealed type is "b.C[builtins.int]"
tmp/a.py:12: error: Value of type variable "S" of "D" cannot be "SS"
tmp/a.py:13: error: Type argument "object" of "D" must be a subtype of "int"

[case testPEP695IncrementalParamSpecAndTypeVarTuple]
import a

[file a.py]
import b

[file a.py.2]
from b import C, D
x1: C[()]
x2: C[int]
x3: C[int, str]
y: D[[int, str]]
reveal_type(y.m)

[file b.py]
class C[*Ts]: pass
class D[**P]:
    def m(self, *args: P.args, **kwargs: P.kwargs) -> None: pass

[builtins fixtures/tuple.pyi]
[out2]
tmp/a.py:6: note: Revealed type is "def (builtins.int, builtins.str)"

[case testPEP695IncrementalTypeAlias]
import a

[file a.py]
import b

[file a.py.2]
from b import A, B
a: A
reveal_type(a)
b: B[int]
reveal_type(b)

[file b.py]
type A = str
class Foo[T]: pass
type B[T] = Foo[T]

[builtins fixtures/tuple.pyi]
[out2]
tmp/a.py:3: note: Revealed type is "builtins.str"
tmp/a.py:5: note: Revealed type is "b.Foo[builtins.int]"

[case testPEP695UndefinedNameInGenericFunction]
def f[T](x: T) -> T:
    return unknown()  # E: Name "unknown" is not defined

class C:
    def m[T](self, x: T) -> T:
        return unknown()  # E: Name "unknown" is not defined

[case testPEP695FunctionTypeVarAccessInFunction]
from typing import cast

class C:
    def m[T](self, x: T) -> T:
        y: T = x
        reveal_type(y)  # N: Revealed type is "T`-1"
        return cast(T, y)

reveal_type(C().m(1))  # N: Revealed type is "builtins.int"

[case testPEP695ScopingBasics]
T = 1

def f[T](x: T) -> T:
    T = 'a'
    reveal_type(T)  # N: Revealed type is "builtins.str"
    return x

reveal_type(T)  # N: Revealed type is "builtins.int"

class C[T]:
    T = 1.2
    reveal_type(T)  # N: Revealed type is "builtins.float"

reveal_type(T)  # N: Revealed type is "builtins.int"

[case testPEP695ClassScoping]
class C:
    class D: pass

    def m[T: D](self, x: T, y: D) -> T:
        return x

C().m(C.D(), C.D())
C().m(1, C.D())  # E: Value of type variable "T" of "m" of "C" cannot be "int"

[case testPEP695NestedGenericFunction]
def f[T](x: T) -> T:
    reveal_type(f(x))  # N: Revealed type is "T`-1"
    reveal_type(f(1))  # N: Revealed type is "builtins.int"

    def ff(x: T) -> T:
        y: T = x
        return y
    reveal_type(ff(x))  # N: Revealed type is "T`-1"
    ff(1)  # E: Argument 1 to "ff" has incompatible type "int"; expected "T"

    def g[S](a: S) -> S:
        ff(a)  # E: Argument 1 to "ff" has incompatible type "S"; expected "T"
        return a
    reveal_type(g(1))  # N: Revealed type is "builtins.int"
    reveal_type(g(x))  # N: Revealed type is "T`-1"

    def h[S](a: S) -> S:
        return a
    reveal_type(h(1))  # N: Revealed type is "builtins.int"
    reveal_type(h(x))  # N: Revealed type is "T`-1"
    return x

[case testPEP695NonLocalAndGlobal]
def f() -> None:
    T = 1
    def g[T](x: T) -> T:
        nonlocal T  # E: nonlocal binding not allowed for type parameter "T"
        T = 'x'  # E: "T" is a type variable and only valid in type context
        return x
    reveal_type(T)  # N: Revealed type is "builtins.int"

def g() -> None:
    a = 1
    def g[T](x: T) -> T:
        nonlocal a
        a = 'x'  # E: Incompatible types in assignment (expression has type "str", variable has type "int")
        return x

x = 1

def h[T](a: T) -> T:
    global x
    x = ''  # E: Incompatible types in assignment (expression has type "str", variable has type "int")
    return a

class C[T]:
    def m[S](self, a: S) -> S:
        global x
        x = ''  # E: Incompatible types in assignment (expression has type "str", variable has type "int")
        return a

[case testPEP695ArgumentDefault]
from typing import cast

def f[T](
    x: T =
        T  # E: Name "T" is not defined \
           # E: Incompatible default for argument "x" (default has type "TypeVar", argument has type "T")
) -> T:
    return x

def g[T](x: T = cast(T, None)) -> T:  # E: Name "T" is not defined
    return x

class C:
    def m[T](self, x: T = cast(T, None)) -> T:  # E: Name "T" is not defined
        return x
[builtins fixtures/tuple.pyi]
[typing fixtures/typing-full.pyi]

[case testPEP695ListComprehension]
from typing import cast

def f[T](x: T) -> T:
    b = [cast(T, a) for a in [1, 2]]
    reveal_type(b)  # N: Revealed type is "builtins.list[T`-1]"
    return x

[case testPEP695ReuseNameInSameScope]
class C[T]:
    def m[S](self, x: S, y: T) -> S | T:
        return x

    def m2[S](self, x: S, y: T) -> S | T:
        return x

class D[T]:
    pass

def f[T](x: T) -> T:
    return x

def g[T](x: T) -> T:
    def nested[S](y: S) -> S:
        return y
    def nested2[S](y: S) -> S:
        return y
    return x

[case testPEP695NestedScopingSpecialCases]
# This is adapted from PEP 695
S = 0

def outer1[S]() -> None:
    S = 1
    T = 1

    def outer2[T]() -> None:
        def inner1() -> None:
            nonlocal S
            nonlocal T  # E: nonlocal binding not allowed for type parameter "T"

        def inner2() -> None:
            global S

[case testPEP695ScopingWithBaseClasses]
# This is adapted from PEP 695
class Outer:
    class Private:
        pass

    # If the type parameter scope was like a traditional scope,
    # the base class 'Private' would not be accessible here.
    class Inner[T](Private, list[T]):
        pass

    # Likewise, 'Inner' would not be available in these type annotations.
    def method1[T](self, a: Inner[T]) -> Inner[T]:
        return a

[case testPEP695RedefineTypeParameterInScope]
class C[T]:
    def m[T](self, x: T) -> T:  # E: "T" already defined as a type parameter
        return x
    def m2(self) -> None:
        def nested[T](x: T) -> T:  # E: "T" already defined as a type parameter
            return x

def f[S, S](x: S) -> S:  # E: "S" already defined as a type parameter
    return x

[case testPEP695ClassDecorator]
from typing import Any

T = 0

def decorator(x: str) -> Any: ...

@decorator(T)  # E: Argument 1 to "decorator" has incompatible type "int"; expected "str"
class C[T]:
    pass

[case testPEP695RecursiceTypeAlias]
type A = str | list[A]
a: A
reveal_type(a)  # N: Revealed type is "Union[builtins.str, builtins.list[...]]"

class C[T]: pass

type B[T] = C[T] | list[B[T]]
b: B[int]
reveal_type(b)  # N: Revealed type is "Union[__main__.C[builtins.int], builtins.list[...]]"
[builtins fixtures/type.pyi]

[case testPEP695BadRecursiveTypeAlias]
type A = A  # E: Cannot resolve name "A" (possible cyclic definition)
type B = B | int  # E: Invalid recursive alias: a union item of itself
a: A
reveal_type(a)  # N: Revealed type is "Any"
b: B
reveal_type(b)  # N: Revealed type is "Any"
[builtins fixtures/type.pyi]
[typing fixtures/typing-full.pyi]

[case testPEP695RecursiveTypeAliasForwardReference]
def f(a: A) -> None:
    if isinstance(a, str):
        reveal_type(a)  # N: Revealed type is "builtins.str"
    else:
        reveal_type(a)  # N: Revealed type is "__main__.C[Union[builtins.str, __main__.C[...]]]"

type A = str | C[A]

class C[T]: pass

f('x')
f(C[str]())
f(C[C[str]]())
f(1)  # E: Argument 1 to "f" has incompatible type "int"; expected "A"
f(C[int]())  # E: Argument 1 to "f" has incompatible type "C[int]"; expected "A"
[builtins fixtures/isinstance.pyi]

[case testPEP695InvalidGenericOrProtocolBaseClass]
from typing import Generic, Protocol, TypeVar

S = TypeVar("S")

class C[T](Generic[T]):  # E: Generic[...] base class is redundant
    pass
class C2[T](Generic[S]): # E: Generic[...] base class is redundant
    pass

a: C[int]
b: C2[int, str]

class P[T](Protocol[T]):  # E: No arguments expected for "Protocol" base class
    pass
class P2[T](Protocol[S]):  # E: No arguments expected for "Protocol" base class
    pass

[case testPEP695CannotUseTypeVarFromOuterClass]
class ClassG[V]:
    # This used to crash
    class ClassD[T: dict[str, V]]:  # E: Name "V" is not defined
        ...
[builtins fixtures/dict.pyi]

[case testPEP695MixNewAndOldStyleGenerics]
from typing import TypeVar

S = TypeVar("S")
U = TypeVar("U")

def f[T](x: T, y: S) -> T | S: ...  # E: All type parameters should be declared ("S" not declared)
def g[T](x: S, y: U) -> T | S | U: ...  # E: All type parameters should be declared ("S", "U" not declared)

def h[S: int](x: S) -> S:
   a: int = x
   return x

class C[T]:
    def m[X, S](self, x: S, y: U) -> X | S | U: ...  # E: All type parameters should be declared ("U" not declared)
    def m2(self, x: T, y: S) -> T | S: ...

class D[T](C[S]):  # E: All type parameters should be declared ("S" not declared)
    pass

[case testPEP695MixNewAndOldStyleTypeVarTupleAndParamSpec]
from typing import TypeVarTuple, ParamSpec, Callable
Ts = TypeVarTuple("Ts")
P = ParamSpec("P")

def f[T](x: T, f: Callable[P, None]  # E: All type parameters should be declared ("P" not declared)
        ) -> Callable[P, T]: ...
def g[T](x: T, f: tuple[*Ts]  # E: All type parameters should be declared ("Ts" not declared)
        ) -> tuple[T, *Ts]: ...
[builtins fixtures/tuple.pyi]

[case testPEP695MixNewAndOldStyleGenericsInTypeAlias]
from typing import TypeVar, ParamSpec, TypeVarTuple, Callable

T = TypeVar("T")
Ts = TypeVarTuple("Ts")
P = ParamSpec("P")

type A = list[T]  # E: All type parameters should be declared ("T" not declared)
a: A[int]  # E: Bad number of arguments for type alias, expected 0, given 1
reveal_type(a)   # N: Revealed type is "builtins.list[Any]"

type B = tuple[*Ts]  # E: All type parameters should be declared ("Ts" not declared)
type C = Callable[P, None]  # E: All type parameters should be declared ("P" not declared)
[builtins fixtures/tuple.pyi]
[typing fixtures/typing-full.pyi]

[case testPEP695NonGenericAliasToGenericClass]
class C[T]: pass
type A = C
x: C
y: A
reveal_type(x)  # N: Revealed type is "__main__.C[Any]"
reveal_type(y)  # N: Revealed type is "__main__.C[Any]"
z: A[int]  # E: Bad number of arguments for type alias, expected 0, given 1

[case testPEP695SelfType]
from typing import Self

class C:
    @classmethod
    def m[T](cls, x: T) -> tuple[Self, T]:
        return cls(), x

class D(C):
    pass

reveal_type(C.m(1))  # N: Revealed type is "tuple[__main__.C, builtins.int]"
reveal_type(D.m(1))  # N: Revealed type is "tuple[__main__.D, builtins.int]"

class E[T]:
    def m(self) -> Self:
        return self

    def mm[S](self, x: S) -> tuple[Self, S]:
        return self, x

class F[T](E[T]):
    pass

reveal_type(E[int]().m())  # N: Revealed type is "__main__.E[builtins.int]"
reveal_type(E[int]().mm(b'x'))  # N: Revealed type is "tuple[__main__.E[builtins.int], builtins.bytes]"
reveal_type(F[str]().m())  # N: Revealed type is "__main__.F[builtins.str]"
reveal_type(F[str]().mm(b'x'))  # N: Revealed type is "tuple[__main__.F[builtins.str], builtins.bytes]"
[builtins fixtures/tuple.pyi]

[case testPEP695CallAlias]
class C:
    def __init__(self, x: str) -> None: ...
type A = C

class D[T]: pass
type B[T] = D[T]

reveal_type(A)  # N: Revealed type is "typing.TypeAliasType"
reveal_type(B)  # N: Revealed type is "typing.TypeAliasType"
reveal_type(B[int])  # N: Revealed type is "typing.TypeAliasType"

A(1)  # E: "TypeAliasType" not callable
B[int]()  # E: "TypeAliasType" not callable

A2 = C
B2 = D
A2(1)  # E: Argument 1 to "C" has incompatible type "int"; expected "str"
B2[int]()
[builtins fixtures/tuple.pyi]
[typing fixtures/typing-full.pyi]

[case testPEP695IncrementalTypeAliasKinds]
import a

[file a.py]
from b import A

[file a.py.2]
from b import A, B, C
A()
B()
C()

[file b.py]
from typing_extensions import TypeAlias
type A = int
B = int
C: TypeAlias = int
[builtins fixtures/tuple.pyi]
[typing fixtures/typing-full.pyi]
[out2]
tmp/a.py:2: error: "TypeAliasType" not callable

[case testPEP695TypeAliasBoundAndValueChecking]
from typing import Any, cast

class C: pass
class D(C): pass

type A[T: C] = list[T]
a1: A
reveal_type(a1)  # N: Revealed type is "builtins.list[Any]"
a2: A[Any]
a3: A[C]
a4: A[D]
a5: A[object]  # E: Type argument "object" of "A" must be a subtype of "C"
a6: A[int]  # E: Type argument "int" of "A" must be a subtype of "C"

x1 = cast(A[C], a1)
x2 = cast(A[None], a1)  # E: Type argument "None" of "A" must be a subtype of "C"

type A2[T: (int, C)] = list[T]
b1: A2
reveal_type(b1)  # N: Revealed type is "builtins.list[Any]"
b2: A2[Any]
b3: A2[int]
b4: A2[C]
b5: A2[D]  # E: Value of type variable "T" of "A2" cannot be "D"
b6: A2[object]  # E: Value of type variable "T" of "A2" cannot be "object"

list[A2[int]]()
list[A2[None]]()  # E: Invalid type argument value for "A2"

class N(int): pass

type A3[T: C, S: (int, str)] = T | S
c1: A3[C, int]
c2: A3[D, str]
c3: A3[C, N]  # E: Value of type variable "S" of "A3" cannot be "N"
c4: A3[int, str]  # E: Type argument "int" of "A3" must be a subtype of "C"
[builtins fixtures/type.pyi]
[typing fixtures/typing-full.pyi]

[case testPEP695TypeAliasInClassBodyOrFunction]
class C:
    type A = int
    type B[T] = list[T] | None
    a: A
    b: B[str]

    def method(self) -> None:
        v: C.A
        reveal_type(v)  # N: Revealed type is "builtins.int"

reveal_type(C.a)  # N: Revealed type is "builtins.int"
reveal_type(C.b)  # N: Revealed type is "Union[builtins.list[builtins.str], None]"

C.A = str  # E: Incompatible types in assignment (expression has type "type[str]", variable has type "TypeAliasType")

x: C.A
y: C.B[int]
reveal_type(x)  # N: Revealed type is "builtins.int"
reveal_type(y)  # N: Revealed type is "Union[builtins.list[builtins.int], None]"

def f() -> None:
    type A = int
    type B[T] = list[T] | None
    a: A
    reveal_type(a)  # N: Revealed type is "builtins.int"

    def g() -> None:
        b: B[int]
        reveal_type(b)  # N: Revealed type is "Union[builtins.list[builtins.int], None]"

class D:
    def __init__(self) -> None:
        type A = int
        self.a: A = 0
        type B[T] = list[T]
        self.b: B[int] = [1]

reveal_type(D().a)  # N: Revealed type is "builtins.int"
reveal_type(D().b)  # N: Revealed type is "builtins.list[builtins.int]"

class E[T]:
    type X = list[T]  # E: All type parameters should be declared ("T" not declared)

    def __init__(self) -> None:
        type A = list[T]  # E: All type parameters should be declared ("T" not declared)
        self.a: A

reveal_type(E[str]().a)  # N: Revealed type is "builtins.list[Any]"
[builtins fixtures/type.pyi]
[typing fixtures/typing-full.pyi]

[case testPEP695TypeAliasInvalidGenericConstraint]
class A[T]:
    class a[S: (int, list[T])]: pass                # E: Name "T" is not defined
    type b[S: (int, list[T])] = S                   # E: TypeVar constraint type cannot be parametrized by type variables
    def c[S: (int, list[T])](self) -> None: ...     # E: TypeVar constraint type cannot be parametrized by type variables
[builtins fixtures/tuple.pyi]
[typing fixtures/typing-full.pyi]

[case testPEP695TypeAliasUnboundTypeVarConstraint]
from typing import TypeVar
T = TypeVar("T")
class a[S: (int, list[T])]: pass                # E: Type variable "__main__.T" is unbound \
                                                # N: (Hint: Use "Generic[T]" or "Protocol[T]" base class to bind "T" inside a class) \
                                                # N: (Hint: Use "T" in function signature to bind "T" inside a function)
type b[S: (int, list[T])] = S                   # E: Type variable "__main__.T" is unbound \
                                                # N: (Hint: Use "Generic[T]" or "Protocol[T]" base class to bind "T" inside a class) \
                                                # N: (Hint: Use "T" in function signature to bind "T" inside a function)
def c[S: (int, list[T])](self) -> None: ...     # E: Type variable "__main__.T" is unbound \
                                                # N: (Hint: Use "Generic[T]" or "Protocol[T]" base class to bind "T" inside a class) \
                                                # N: (Hint: Use "T" in function signature to bind "T" inside a function)
[builtins fixtures/tuple.pyi]
[typing fixtures/typing-full.pyi]

[case testPEP695RedefineAsTypeAlias1]
class C: pass
type C = int  # E: Name "C" already defined on line 1

A = 0
type A = str  # E: Name "A" already defined on line 4
reveal_type(A)  # N: Revealed type is "builtins.int"

[case testPEP695RedefineAsTypeAlias2]
from m import D
type D = int  # E: Name "D" already defined (possibly by an import)
a: D
reveal_type(a)  # N: Revealed type is "m.D"
[file m.py]
class D: pass

[case testPEP695RedefineAsTypeAlias3]
D = list["Forward"]
type D = int  # E: Name "D" already defined on line 1
Forward = str
x: D
reveal_type(x)  # N: Revealed type is "builtins.list[builtins.str]"

[case testPEP695MultiDefinitionsForTypeAlias]
if int():
    type A[T] = list[T]
else:
    type A[T] = str  # E: Name "A" already defined on line 2
x: T  # E: Name "T" is not defined
a: A[int]
reveal_type(a)  # N: Revealed type is "builtins.list[builtins.int]"

[case testPEP695UndefinedNameInAnnotation]
def f[T](x: foobar, y: T) -> T: ...  # E: Name "foobar" is not defined
reveal_type(f)  # N: Revealed type is "def [T] (x: Any, y: T`-1) -> T`-1"

[case testPEP695WrongNumberOfConstrainedTypes]
type A[T: ()] = list[T]  # E: Type variable must have at least two constrained types
a: A[int]
reveal_type(a)  # N: Revealed type is "builtins.list[builtins.int]"

type B[T: (int,)] = list[T]  # E: Type variable must have at least two constrained types
b: B[str]
reveal_type(b)  # N: Revealed type is "builtins.list[builtins.str]"

[case testPEP695UsingTypeVariableInOwnBoundOrConstraint]
type A[T: list[T]] = str  # E: Name "T" is not defined
type B[S: (list[S], str)] = str  # E: Name "S" is not defined
type C[T, S: list[T]] = str  # E: Name "T" is not defined

def f[T: T](x: T) -> T: ...  # E: Name "T" is not defined
class D[T: T]:  # E: Name "T" is not defined
    pass

[case testPEP695InvalidType]
def f[T: 1](x: T) -> T: ...  # E: Invalid type: try using Literal[1] instead?
class C[T: (int, (1 + 2))]: pass  # E: Invalid type comment or annotation
type A = list[1]  # E: Invalid type: try using Literal[1] instead?
type B = (1 + 2)  # E: Invalid type alias: expression is not a valid type
a: A
reveal_type(a)  # N: Revealed type is "builtins.list[Any]"
b: B
reveal_type(b)  # N: Revealed type is "Any"

[case testPEP695GenericNamedTuple]
from typing import NamedTuple

# Invariant because of the signature of the generated _replace method
class N[T](NamedTuple):
    x: T
    y: int

a: N[object]
reveal_type(a.x)  # N: Revealed type is "builtins.object"
b: N[int]
reveal_type(b.x)  # N: Revealed type is "builtins.int"
if int():
    a = b  # E: Incompatible types in assignment (expression has type "N[int]", variable has type "N[object]")
if int():
    b = a  # E: Incompatible types in assignment (expression has type "N[object]", variable has type "N[int]")

class M[T: (int, str)](NamedTuple):
    x: T

c: M[int]
d: M[str]
e: M[bool]  # E: Value of type variable "T" of "M" cannot be "bool"
[builtins fixtures/tuple.pyi]
[typing fixtures/typing-full.pyi]

[case testPEP695GenericTypedDict]
from typing import TypedDict

class D[T](TypedDict):
    x: T
    y: int

class E[T: str](TypedDict):
    x: T
    y: int

a: D[object]
reveal_type(a["x"])  # N: Revealed type is "builtins.object"
b: D[int]
reveal_type(b["x"])  # N: Revealed type is "builtins.int"
c: E[str]
d: E[int]  # E: Type argument "int" of "E" must be a subtype of "str"
[builtins fixtures/tuple.pyi]
[typing fixtures/typing-full.pyi]

[case testCurrentClassWorksAsBound]
from typing import Protocol

class Comparable[T: Comparable](Protocol):
    def compare(self, other: T) -> bool: ...

class Good:
    def compare(self, other: Good) -> bool: ...

x: Comparable[Good]
y: Comparable[int]  # E: Type argument "int" of "Comparable" must be a subtype of "Comparable[Any]"

[case testPEP695TypeAliasWithDifferentTargetTypes]
import types  # We need GenericAlias from here, and test stubs don't bring in 'types'
from typing import Any, Callable, List, Literal, TypedDict

# Test that various type expressions don't generate false positives as type alias
# values, as they are type checked as expressions. There is a similar test case in
# pythoneval.test that uses typeshed stubs.

class C[T]: pass

class TD(TypedDict):
    x: int

type A1 = type[int]
type A2 = type[int] | None
type A3 = None | type[int]
type A4 = type[Any]

type B1[**P, R] = Callable[P, R] | None
type B2[**P, R] = None | Callable[P, R]
type B3 = Callable[[str], int]
type B4 = Callable[..., int]

type C1 = A1 | None
type C2 = None | A1

type D1 = Any | None
type D2 = None | Any

type E1 = List[int]
type E2 = List[int] | None
type E3 = None | List[int]

type F1 = Literal[1]
type F2 = Literal['x'] | None
type F3 = None | Literal[True]

type G1 = tuple[int, Any]
type G2 = tuple[int, Any] | None
type G3 = None | tuple[int, Any]

type H1 = TD
type H2 = TD | None
type H3 = None | TD

type I1 = C[int]
type I2 = C[Any] | None
type I3 = None | C[TD]
[builtins fixtures/type.pyi]
[typing fixtures/typing-full.pyi]

[case testTypedDictInlineYesNewStyleAlias]
# flags: --enable-incomplete-feature=InlineTypedDict
type X[T] = {"item": T, "other": X[T] | None}
x: X[str]
reveal_type(x)  # N: Revealed type is "TypedDict({'item': builtins.str, 'other': Union[..., None]})"
if x["other"] is not None:
    reveal_type(x["other"]["item"])  # N: Revealed type is "builtins.str"

type Y[T] = {"item": T, **Y[T]}  # E: Overwriting TypedDict field "item" while merging
[builtins fixtures/dict.pyi]
[typing fixtures/typing-full.pyi]

[case testTypedDictInlinePEP764YesNewStyleAlias]
# flags: --enable-incomplete-feature=NewInlineTypedDict
from typing import TypedDict
type X[T] = TypedDict[{"item": T, "other": X[T] | None}]
x: X[str]
reveal_type(x)  # N: Revealed type is "TypedDict({'item': builtins.str, 'other': Union[..., None]})"
if x["other"] is not None:
    reveal_type(x["other"]["item"])  # N: Revealed type is "builtins.str"
[builtins fixtures/dict.pyi]
[typing fixtures/typing-full.pyi]

[case testPEP695UsingIncorrectExpressionsInTypeVariableBound]
type X[T: (yield 1)] = Any  # E: Yield expression cannot be used as a type variable bound
type Y[T: (yield from [])] = Any # E: Yield expression cannot be used as a type variable bound
type Z[T: (a := 1)] = Any  # E: Named expression cannot be used as a type variable bound
type K[T: (await 1)] = Any # E: Await expression cannot be used as a type variable bound

type XNested[T: (1 + (yield 1))] = Any  # E: Yield expression cannot be used as a type variable bound
type YNested[T: (1 + (yield from []))] = Any # E: Yield expression cannot be used as a type variable bound
type ZNested[T: (1 + (a := 1))] = Any  # E: Named expression cannot be used as a type variable bound
type KNested[T: (1 + (await 1))] = Any # E: Await expression cannot be used as a type variable bound

class FooX[T: (yield 1)]: pass  # E: Yield expression cannot be used as a type variable bound
class FooY[T: (yield from [])]: pass  # E: Yield expression cannot be used as a type variable bound
class FooZ[T: (a := 1)]: pass  # E: Named expression cannot be used as a type variable bound
class FooK[T: (await 1)]: pass  # E: Await expression cannot be used as a type variable bound

class FooXNested[T: (1 + (yield 1))]: pass  # E: Yield expression cannot be used as a type variable bound
class FooYNested[T: (1 + (yield from []))]: pass  # E: Yield expression cannot be used as a type variable bound
class FooZNested[T: (1 + (a := 1))]: pass  # E: Named expression cannot be used as a type variable bound
class FooKNested[T: (1 + (await 1))]: pass  # E: Await expression cannot be used as a type variable bound

def foox[T: (yield 1)](): pass  # E: Yield expression cannot be used as a type variable bound
def fooy[T: (yield from [])](): pass  # E: Yield expression cannot be used as a type variable bound
def fooz[T: (a := 1)](): pass  # E: Named expression cannot be used as a type variable bound
def fook[T: (await 1)](): pass  # E: Await expression cannot be used as a type variable bound

def foox_nested[T: (1 + (yield 1))](): pass  # E: Yield expression cannot be used as a type variable bound
def fooy_nested[T: (1 + (yield from []))](): pass  # E: Yield expression cannot be used as a type variable bound
def fooz_nested[T: (1 + (a := 1))](): pass  # E: Named expression cannot be used as a type variable bound
def fook_nested[T: (1 +(await 1))](): pass  # E: Await expression cannot be used as a type variable bound

[case testPEP695UsingIncorrectExpressionsInTypeAlias]
type X = (yield 1)  # E: Yield expression cannot be used within a type alias
type Y = (yield from []) # E: Yield expression cannot be used within a type alias
type Z = (a := 1)  # E: Named expression cannot be used within a type alias
type K = (await 1)  # E: Await expression cannot be used within a type alias

type XNested = (1 + (yield 1))  # E: Yield expression cannot be used within a type alias
type YNested = (1 + (yield from [])) # E: Yield expression cannot be used within a type alias
type ZNested = (1 + (a := 1))  # E: Named expression cannot be used within a type alias
type KNested = (1 + (await 1))  # E: Await expression cannot be used within a type alias

[case testPEP695TypeAliasAndAnnotated]
from typing_extensions import Annotated, Annotated as _Annotated
import typing_extensions as t

def ann(*args): ...

type A = Annotated[int, ann()]
type B = Annotated[int | str, ann((1, 2))]
type C = _Annotated[int, ann()]
type D = t.Annotated[str, ann()]

x: A
y: B
z: C
zz: D
reveal_type(x)  # N: Revealed type is "builtins.int"
reveal_type(y)  # N: Revealed type is "Union[builtins.int, builtins.str]"
reveal_type(z)  # N: Revealed type is "builtins.int"
reveal_type(zz)  # N: Revealed type is "builtins.str"
[builtins fixtures/tuple.pyi]

[case testPEP695NestedGenericClass1]
class C[T]:
    def f(self) -> T: ...

class A:
    class B[Q]:
        def __init__(self, a: Q) -> None:
            self.a = a

        def f(self) -> Q:
            return self.a

        def g(self, x: Q) -> None: ...

    b: B[str]

x: A.B[int]
x.g("x")  # E: Argument 1 to "g" of "B" has incompatible type "str"; expected "int"
reveal_type(x.a)  # N: Revealed type is "builtins.int"
reveal_type(x)  # N: Revealed type is "__main__.A.B[builtins.int]"
reveal_type(A.b)  # N: Revealed type is "__main__.A.B[builtins.str]"

[case testPEP695NestedGenericClass2]
class A:
    def m(self) -> None:
        class B[T]:
            def f(self) -> T: ...
        x: B[int]
        reveal_type(x.f())  # N: Revealed type is "builtins.int"
        self.a = B[str]()

reveal_type(A().a)  # N: Revealed type is "__main__.B@3[builtins.str]"
reveal_type(A().a.f())  # N: Revealed type is "builtins.str"

[case testPEP695NestedGenericClass3]
class C[T]:
    def f(self) -> T: ...
    class D[S]:
        x: T  # E: Name "T" is not defined
        def g(self) -> S: ...

a: C[int]
reveal_type(a.f())  # N: Revealed type is "builtins.int"
b: C.D[str]
reveal_type(b.g())  # N: Revealed type is "builtins.str"

class E[T]:
    class F[T]:  # E: "T" already defined as a type parameter
        x: T

c: E.F[int]

[case testPEP695NestedGenericClass4]
class A:
    class B[T]:
        def __get__(self, instance: A, owner: type[A]) -> T:
            return None  # E: Incompatible return value type (got "None", expected "T")
    f = B[int]()

a = A()
v = a.f

[case testPEP695VarianceInheritedFromBaseWithExplicitVariance]
from typing import TypeVar, Generic

T = TypeVar("T")

class ParentInvariant(Generic[T]):
    pass

class Invariant1[T](ParentInvariant[T]):
    pass

a1: Invariant1[int] = Invariant1[float]()  # E: Incompatible types in assignment (expression has type "Invariant1[float]", variable has type "Invariant1[int]")
a2: Invariant1[float] = Invariant1[int]()  # E: Incompatible types in assignment (expression has type "Invariant1[int]", variable has type "Invariant1[float]")

T_contra = TypeVar("T_contra", contravariant=True)

class ParentContravariant(Generic[T_contra]):
    pass

class Contravariant[T](ParentContravariant[T]):
    pass

b1: Contravariant[int] = Contravariant[float]()
b2: Contravariant[float] = Contravariant[int]()  # E: Incompatible types in assignment (expression has type "Contravariant[int]", variable has type "Contravariant[float]")

class Invariant2[T](ParentContravariant[T]):
    def f(self) -> T: ...

c1: Invariant2[int] = Invariant2[float]()  # E: Incompatible types in assignment (expression has type "Invariant2[float]", variable has type "Invariant2[int]")
c2: Invariant2[float] = Invariant2[int]()  # E: Incompatible types in assignment (expression has type "Invariant2[int]", variable has type "Invariant2[float]")

class Multi[T, S](ParentInvariant[T], ParentContravariant[S]):
    pass

d1: Multi[int, str] = Multi[float, str]()  # E: Incompatible types in assignment (expression has type "Multi[float, str]", variable has type "Multi[int, str]")
d2: Multi[float, str] = Multi[int, str]()  # E: Incompatible types in assignment (expression has type "Multi[int, str]", variable has type "Multi[float, str]")
d3: Multi[str, int] = Multi[str, float]()
d4: Multi[str, float] = Multi[str, int]()  # E: Incompatible types in assignment (expression has type "Multi[str, int]", variable has type "Multi[str, float]")

[case testPEP695MultipleNestedGenericClass1]
# flags: --enable-incomplete-feature=NewGenericSyntax
class A:
    class B:
        class C:
            class D[Q]:
                def g(self, x: Q): ...
            d: D[str]

x: A.B.C.D[int]
x.g('a') # E: Argument 1 to "g" of "D" has incompatible type "str"; expected "int"
reveal_type(x)  # N: Revealed type is "__main__.A.B.C.D[builtins.int]"
reveal_type(A.B.C.d)  # N: Revealed type is "__main__.A.B.C.D[builtins.str]"

[case testPEP695MultipleNestedGenericClass2]
# flags: --enable-incomplete-feature=NewGenericSyntax
class A:
    class B:
        def m(self) -> None:
            class C[T]:
                def f(self) -> T: ...
            x: C[int]
            reveal_type(x.f())  # N: Revealed type is "builtins.int"
            self.a = C[str]()

reveal_type(A().B().a) # N: Revealed type is "__main__.C@5[builtins.str]"

[case testPEP695MultipleNestedGenericClass3]
# flags: --enable-incomplete-feature=NewGenericSyntax
class A:
    class C[T]:
        def f(self) -> T: ...
        class D[S]:
            x: T  # E: Name "T" is not defined
            def g(self) -> S: ...

a: A.C[int]
reveal_type(a.f())  # N: Revealed type is "builtins.int"
b: A.C.D[str]
reveal_type(b.g())  # N: Revealed type is "builtins.str"

class B:
    class E[T]:
        class F[T]:  # E: "T" already defined as a type parameter
            x: T

c: B.E.F[int]

[case testPEP695MultipleNestedGenericClass4]
# flags: --enable-incomplete-feature=NewGenericSyntax
class Z:
    class A:
        class B[T]:
            def __get__(self, instance: Z.A, owner: type[Z.A]) -> T:
                return None  # E: Incompatible return value type (got "None", expected "T")
        f = B[int]()

a = Z.A()
v = a.f

[case testPEP695MultipleNestedGenericClass5]
# flags: --enable-incomplete-feature=NewGenericSyntax
from a.b.c import d
x: d.D.E.F.G[int]
x.g('a') # E: Argument 1 to "g" of "G" has incompatible type "str"; expected "int"
reveal_type(x)  # N: Revealed type is "a.b.c.d.D.E.F.G[builtins.int]"
reveal_type(d.D.E.F.d)  # N: Revealed type is "a.b.c.d.D.E.F.G[builtins.str]"

[file a/b/c/d.py]
class D:
    class E:
        class F:
            class G[Q]:
                def g(self, x: Q): ...
            d: G[str]

[case testTypeAliasNormalization]
from collections.abc import Callable
from typing import Unpack
from typing_extensions import TypeAlias

type RK_function_args = tuple[float, int]
type RK_functionBIS = Callable[[Unpack[RK_function_args], int], int]

def ff(a: float, b: int, c: int) -> int:
    return 2

bis: RK_functionBIS = ff
res: int = bis(1.0, 2, 3)
[builtins fixtures/tuple.pyi]
[typing fixtures/typing-full.pyi]

[case testPEP695TypeAliasNotReadyClass]
class CustomizeResponse:
    related_resources: "ResourceRule"

class ResourceRule: pass

class DecoratorController:
    type CustomizeResponse = CustomizeResponse

x: DecoratorController.CustomizeResponse
reveal_type(x.related_resources)  # N: Revealed type is "__main__.ResourceRule"
[builtins fixtures/tuple.pyi]

[case testPEP695TypeAliasRecursiveOuterClass]
class A:
    type X = X  # E: Cannot resolve name "X" (possible cyclic definition)
class X: ...

class AA:
    XX = XX  # OK, we allow this as a special case.
class XX: ...

class Y: ...
class B:
    type Y = Y

reveal_type(AA.XX)  # N: Revealed type is "def () -> __main__.XX"
y: B.Y
reveal_type(y)  # N: Revealed type is "__main__.Y"
[builtins fixtures/tuple.pyi]

[case testPEP695TypeAliasRecursiveInvalid]
type X = X  # E: Cannot resolve name "X" (possible cyclic definition)
type Z = Z[int]  # E: Cannot resolve name "Z" (possible cyclic definition)
def foo() -> None:
    type X = X  # OK, refers to outer (invalid) X
    x: X
    reveal_type(x)  # N: Revealed type is "Any"
    type Y = Y  # E: Cannot resolve name "Y" (possible cyclic definition) \
                # N: Recursive types are not allowed at function scope
class Z: ...  # E: Name "Z" already defined on line 2
[builtins fixtures/tuple.pyi]
[typing fixtures/typing-full.pyi]

[case testPEP695MultipleUnpacksInBareApplicationNoCrash]
# https://github.com/python/mypy/issues/18856
class A[*Ts]: ...

A[*tuple[int, ...], *tuple[int, ...]]  # E: More than one Unpack in a type is not allowed
a: A[*tuple[int, ...], *tuple[int, ...]]  # E: More than one Unpack in a type is not allowed
def foo(a: A[*tuple[int, ...], *tuple[int, ...]]): ...  # E: More than one Unpack in a type is not allowed

tuple[*tuple[int, ...], *tuple[int, ...]]  # E: More than one Unpack in a type is not allowed
b: tuple[*tuple[int, ...], *tuple[int, ...]]  # E: More than one Unpack in a type is not allowed
[builtins fixtures/tuple.pyi]
[typing fixtures/typing-full.pyi]

[case testForwardNestedPrecedesForwardGlobal]
from typing import NewType

class W[T]: pass

class R:
    class M(W[Action.V], type):
        FOO = R.Action.V(0)
    class Action(metaclass=M):
        V = NewType('V', int)

class Action:
    pass

[case testPEP695TypeVarConstraintsDefaultAliases]
from typing import Generic
from typing_extensions import TypeVar

type K = int
type V = int
type L = list[int]

T1 = TypeVar("T1", str, K, default=K)
T2 = TypeVar("T2", str, K, default=V)
T3 = TypeVar("T3", str, L, default=L)

class A1(Generic[T1]):
    x: T1
class A2(Generic[T2]):
    x: T2
class A3(Generic[T3]):
    x: T3

reveal_type(A1().x)  # N: Revealed type is "builtins.int"
reveal_type(A2().x)  # N: Revealed type is "builtins.int"
reveal_type(A3().x)  # N: Revealed type is "builtins.list[builtins.int]"
[builtins fixtures/tuple.pyi]