check-selftype.test

[case testSelfTypeInstance]
from typing import TypeVar

T = TypeVar('T', bound='A', covariant=True)

class A:
    def copy(self: T) -> T: pass

class B(A):
    pass

reveal_type(A().copy)  # N: Revealed type is "def () -> __main__.A"
reveal_type(B().copy)  # N: Revealed type is "def () -> __main__.B"
reveal_type(A().copy())  # N: Revealed type is "__main__.A"
reveal_type(B().copy())  # N: Revealed type is "__main__.B"

[builtins fixtures/bool.pyi]

[case testSelfTypeStaticAccess]
from typing import TypeVar

T = TypeVar('T', bound='A', covariant=True)
class A:
    def copy(self: T) -> T: pass

class B(A):
    pass

# Erased instances appear on reveal_type; unrelated to self type
def f(a: A) -> None: pass
f(A.copy(A()))
f(A.copy(B()))
f(B.copy(B()))

# TODO: make it an error
# f(B.copy(A()))

def g(a: B) -> None: pass
g(A.copy(A()))  # E: Argument 1 to "g" has incompatible type "A"; expected "B"
g(A.copy(B()))
g(B.copy(B()))

[builtins fixtures/bool.pyi]

[case testSelfTypeReturn]
from typing import TypeVar, Type

R = TypeVar('R')
def _type(self: R) -> Type[R]: pass

T = TypeVar('T', bound='A', covariant=True)
class A:
    def copy(self: T) -> T:
        if B():
            return A()  # E: Incompatible return value type (got "A", expected "T")
        elif A():
            return B()  # E: Incompatible return value type (got "B", expected "T")
        reveal_type(_type(self))  # N: Revealed type is "Type[T`-1]"
        return reveal_type(_type(self)())  # N: Revealed type is "T`-1"

class B(A):
    pass

Q = TypeVar('Q', bound='C', covariant=True)
class C:
    def __init__(self, a: int) -> None: pass

    def copy(self: Q) -> Q:
        if self:
            return reveal_type(_type(self)(1))  # N: Revealed type is "Q`-1"
        else:
            return _type(self)()  # E: Missing positional argument "a" in call to "C"


[builtins fixtures/bool.pyi]

[case testSelfTypeClass]
from typing import TypeVar, Type

T = TypeVar('T', bound='A')

class A:
    @classmethod
    def new(cls: Type[T]) -> T:
        return reveal_type(cls())  # N: Revealed type is "T`-1"

class B(A):
    pass

Q = TypeVar('Q', bound='C', covariant=True)
class C:
    def __init__(self, a: int) -> None: pass

    @classmethod
    def new(cls: Type[Q]) -> Q:
        if cls:
            return cls(1)
        else:
            return cls()  # E: Missing positional argument "a" in call to "C"


reveal_type(A.new)  # N: Revealed type is "def () -> __main__.A"
reveal_type(B.new)  # N: Revealed type is "def () -> __main__.B"
reveal_type(A.new())  # N: Revealed type is "__main__.A"
reveal_type(B.new())  # N: Revealed type is "__main__.B"

[builtins fixtures/classmethod.pyi]

[case testSelfTypeOverride]
from typing import TypeVar, cast

T = TypeVar('T', bound='A', covariant=True)

class A:
    def copy(self: T) -> T: pass

class B(A):
    pass

Q = TypeVar('Q', bound='C', covariant=True)
class C(A):
    def copy(self: Q) -> Q: pass

reveal_type(C().copy)  # N: Revealed type is "def () -> __main__.C"
reveal_type(C().copy())  # N: Revealed type is "__main__.C"
reveal_type(cast(A, C()).copy)  # N: Revealed type is "def () -> __main__.A"
reveal_type(cast(A, C()).copy())  # N: Revealed type is "__main__.A"

[builtins fixtures/bool.pyi]

[case testSelfTypeOverrideCompatibility]
from typing import overload, TypeVar, Generic

T = TypeVar("T")

class A(Generic[T]):
    @overload
    def f(self: A[int]) -> int: ...
    @overload
    def f(self: A[str]) -> str: ...
    def f(self): ...

class B(A[T]):
    @overload
    def f(self: A[int]) -> int: ...
    @overload
    def f(self: A[str]) -> str: ...
    def f(self): ...

class B2(A[T]):
    @overload
    def f(self: A[int]) -> int: ...
    @overload
    def f(self: A[str]) -> str: ...
    @overload
    def f(self: A[bytes]) -> bytes: ...
    def f(self): ...

class C(A[int]):
    def f(self) -> int: ...

class D(A[str]):
    def f(self) -> int: ...  # E: Signature of "f" incompatible with supertype "A" \
                             # N:      Superclass:            \
                             # N:          @overload          \
                             # N:          def f(self) -> str \
                             # N:      Subclass:              \
                             # N:          def f(self) -> int

class E(A[T]):
    def f(self) -> int: ...  # E: Signature of "f" incompatible with supertype "A" \
                             # N:      Superclass:            \
                             # N:          @overload          \
                             # N:          def f(self) -> int \
                             # N:          @overload          \
                             # N:          def f(self) -> str \
                             # N:      Subclass:              \
                             # N:          def f(self) -> int


class F(A[bytes]):
    # Note there's an argument to be made that this is actually compatible with the supertype
    def f(self) -> bytes: ...  # E: Signature of "f" incompatible with supertype "A" \
                               # N:      Superclass:            \
                               # N:          @overload          \
                               # N:          def f(self) -> int \
                               # N:          @overload          \
                               # N:          def f(self) -> str \
                               # N:      Subclass:              \
                               # N:          def f(self) -> bytes

class G(A):
    def f(self): ...

class H(A[int]):
    def f(self): ...

class I(A[int]):
    def f(*args): ...

class J(A[int]):
    def f(self, arg) -> int: ...  # E: Signature of "f" incompatible with supertype "A" \
                                  # N:      Superclass:            \
                                  # N:          @overload          \
                                  # N:          def f(self) -> int \
                                  # N:      Subclass:              \
                                  # N:          def f(self, arg: Any) -> int

[builtins fixtures/tuple.pyi]

[case testSelfTypeOverrideCompatibilityGeneric]
from typing import TypeVar, Generic, overload

T = TypeVar("T", str, int, None)

class A(Generic[T]):
    @overload
    def f(self, s: T) -> T: ...
    @overload
    def f(self: A[str], s: bytes) -> str: ...
    def f(self, s: object): ...

class B(A[int]):
    def f(self, s: int) -> int: ...

class C(A[None]):
    def f(self, s: int) -> int: ...  # E: Signature of "f" incompatible with supertype "A" \
                                     # N:      Superclass:            \
                                     # N:          @overload          \
                                     # N:          def f(self, s: None) -> None \
                                     # N:      Subclass:              \
                                     # N:          def f(self, s: int) -> int
[builtins fixtures/tuple.pyi]

[case testSelfTypeOverrideCompatibilityTypeVar]
from typing import overload, TypeVar, Union

AT = TypeVar("AT", bound="A")

class A:
    @overload
    def f(self: AT, x: int) -> AT: ...
    @overload
    def f(self, x: str) -> None: ...
    @overload
    def f(self: AT) -> bytes: ...
    def f(*a, **kw): ...

class B(A):
    @overload  # E: Signature of "f" incompatible with supertype "A" \
               # N:      Superclass:                                 \
               # N:          @overload                               \
               # N:          def f(self, x: int) -> B                \
               # N:          @overload                               \
               # N:          def f(self, x: str) -> None             \
               # N:          @overload                               \
               # N:          def f(self) -> bytes                    \
               # N:      Subclass:                                   \
               # N:          @overload                               \
               # N:          def f(self, x: int) -> B                \
               # N:          @overload                               \
               # N:          def f(self, x: str) -> None
    def f(self, x: int) -> B: ...
    @overload
    def f(self, x: str) -> None: ...
    def f(*a, **kw): ...
[builtins fixtures/dict.pyi]

[case testSelfTypeOverrideCompatibilitySelfTypeVar]
from typing import Any, Generic, Self, TypeVar, overload

T_co = TypeVar('T_co', covariant=True)

class Config(Generic[T_co]):
	@overload
	def get(self, instance: None) -> Self: ...
	@overload
	def get(self, instance: Any) -> T_co: ...
	def get(self, *a, **kw): ...

class MultiConfig(Config[T_co]):
	@overload
	def get(self, instance: None) -> Self: ...
	@overload
	def get(self, instance: Any) -> T_co: ...
	def get(self, *a, **kw): ...
[builtins fixtures/dict.pyi]

[case testSelfTypeSuper]
from typing import TypeVar, cast

T = TypeVar('T', bound='A', covariant=True)

class A:
    def copy(self: T) -> T: pass

Q = TypeVar('Q', bound='B', covariant=True)
class B(A):
    def copy(self: Q) -> Q:
        reveal_type(self)  # N: Revealed type is "Q`-1"
        reveal_type(super().copy)  # N: Revealed type is "def () -> Q`-1"
        return super().copy()

[builtins fixtures/bool.pyi]

[case testSelfTypeRecursiveBinding]
from typing import TypeVar, Callable, Type

T = TypeVar('T', bound='A', covariant=True)
class A:
    # TODO: This is potentially unsafe, as we use T in an argument type
    def copy(self: T, factory: Callable[[T], T]) -> T:
        return factory(self)

    @classmethod
    def new(cls: Type[T], factory: Callable[[T], T]) -> T:
        reveal_type(cls)   # N: Revealed type is "Type[T`-1]"
        reveal_type(cls())   # N: Revealed type is "T`-1"
        cls(2)  # E: Too many arguments for "A"
        return cls()

class B(A):
    pass

reveal_type(A().copy)  # N: Revealed type is "def (factory: def (__main__.A) -> __main__.A) -> __main__.A"
reveal_type(B().copy)  # N: Revealed type is "def (factory: def (__main__.B) -> __main__.B) -> __main__.B"
reveal_type(A.new)  # N: Revealed type is "def (factory: def (__main__.A) -> __main__.A) -> __main__.A"
reveal_type(B.new)  # N: Revealed type is "def (factory: def (__main__.B) -> __main__.B) -> __main__.B"

[builtins fixtures/classmethod.pyi]

[case testSelfTypeBound]
from typing import TypeVar, Callable, cast

TA = TypeVar('TA', bound='A', covariant=True)

class A:
    def copy(self: TA) -> TA:
        pass

class C(A):
    def copy(self: C) -> C:
        pass

class D(A):
   def copy(self: A) -> A:  # E: Return type "A" of "copy" incompatible with return type "D" in supertype "A"
       pass

TB = TypeVar('TB', bound='B', covariant=True)
class B(A):
    x = 1
    def copy(self: TB) -> TB:
        reveal_type(self.x)  # N: Revealed type is "builtins.int"
        return cast(TB, None)

[builtins fixtures/bool.pyi]

-- # TODO: fail for this
-- [case testSelfTypeBare]
-- from typing import TypeVar, Type
--
-- T = TypeVar('T', bound='E')
--
-- class E:
--     def copy(self: T, other: T) -> T: pass

[case testSelfTypeClone]
from typing import TypeVar, Type
T = TypeVar('T', bound='C')

class C:
    def copy(self: T) -> T:
        return self

    @classmethod
    def new(cls: Type[T]) -> T:
        return cls()

class D(C): pass

reveal_type(D.new)  # N: Revealed type is "def () -> __main__.D"
reveal_type(D().new)  # N: Revealed type is "def () -> __main__.D"
reveal_type(D.new())  # N: Revealed type is "__main__.D"
reveal_type(D().new())  # N: Revealed type is "__main__.D"

Q = TypeVar('Q', bound=C)

def clone(arg: Q) -> Q:
    reveal_type(arg.copy)  # N: Revealed type is "def () -> Q`-1"
    reveal_type(arg.copy())  # N: Revealed type is "Q`-1"
    reveal_type(arg.new)  # N: Revealed type is "def () -> Q`-1"
    reveal_type(arg.new())  # N: Revealed type is "Q`-1"
    return arg.copy()

def make(cls: Type[Q]) -> Q:
    reveal_type(cls.new)  # N: Revealed type is "def () -> Q`-1"
    reveal_type(cls().new)  # N: Revealed type is "def () -> Q`-1"
    reveal_type(cls().new())  # N: Revealed type is "Q`-1"
    return cls.new()

[builtins fixtures/classmethod.pyi]

[case testSelfTypeGeneric]
from typing import TypeVar

T = TypeVar('T', int, str)

class A:
    pass

class B(A):
    def __init__(self, arg: T) -> None:
        super(B, self).__init__()

[case testSelfTypeNonsensical]
from typing import TypeVar, Type

T = TypeVar('T', bound=str)
class A:
    def foo(self: T) -> T:   # E: The erased type of self "builtins.str" is not a supertype of its class "__main__.A"
        return self

    @classmethod
    def cfoo(cls: Type[T]) -> T:  # E: The erased type of self "Type[builtins.str]" is not a supertype of its class "Type[__main__.A]"
        return cls()

Q = TypeVar('Q', bound='B')
class B:
    def foo(self: Q) -> Q:
        return self

    @classmethod
    def cfoo(cls: Type[Q]) -> Q:
        return cls()

class C:
    def foo(self: C) -> C: return self

    @classmethod
    def cfoo(cls: Type[C]) -> C:
        return cls()

class D:
    def foo(self: Q) -> Q:  # E: The erased type of self "__main__.B" is not a supertype of its class "__main__.D"
        return self

    @staticmethod
    def bar(self: str) -> str:
        return self

    @classmethod
    def cfoo(cls: Type[Q]) -> Q:  # E: The erased type of self "Type[__main__.B]" is not a supertype of its class "Type[__main__.D]"
        return cls()

[builtins fixtures/classmethod.pyi]

[case testSelfTypeLambdaDefault]
from typing import Callable
class C:
    @classmethod
    def foo(cls,
            arg: Callable[[int], str] = lambda a: ''
            ) -> None:
        pass

    def bar(self,
            arg: Callable[[int], str] = lambda a: ''
            ) -> None:
        pass
[builtins fixtures/classmethod.pyi]

[case testSelfTypeNew]
from typing import TypeVar, Type

T = TypeVar('T', bound='A')
class A:
    def __new__(cls: Type[T]) -> T:
        return cls()

    def __init_subclass__(cls: Type[T]) -> None:
        pass

class B:
    def __new__(cls: Type[T]) -> T:  # E: The erased type of self "Type[__main__.A]" is not a supertype of its class "Type[__main__.B]"
        return cls()

    def __init_subclass__(cls: Type[T]) -> None:  # E: The erased type of self "Type[__main__.A]" is not a supertype of its class "Type[__main__.B]"
        pass

class C:
    def __new__(cls: Type[C]) -> C:
        return cls()

    def __init_subclass__(cls: Type[C]) -> None:
        pass

class D:
    def __new__(cls: D) -> D:  # E: The erased type of self "__main__.D" is not a supertype of its class "Type[__main__.D]"
        return cls

    def __init_subclass__(cls: D) -> None:  # E: The erased type of self "__main__.D" is not a supertype of its class "Type[__main__.D]"
        pass

class E:
    def __new__(cls) -> E:
        reveal_type(cls)  # N: Revealed type is "Type[__main__.E]"
        return cls()

    def __init_subclass__(cls) -> None:
        reveal_type(cls)  # N: Revealed type is "Type[__main__.E]"

[case testSelfTypeNew_explicit]
from typing import TypeVar, Type

T = TypeVar('T', bound='A')
class A:
    @staticmethod
    def __new__(cls: Type[T]) -> T:
        return cls()

    @classmethod
    def __init_subclass__(cls: Type[T]) -> None:
        pass

class B:
    @staticmethod
    def __new__(cls: Type[T]) -> T:  # E: The erased type of self "Type[__main__.A]" is not a supertype of its class "Type[__main__.B]"
        return cls()

    @classmethod
    def __init_subclass__(cls: Type[T]) -> None:  # E: The erased type of self "Type[__main__.A]" is not a supertype of its class "Type[__main__.B]"
        pass

class C:
    @staticmethod
    def __new__(cls: Type[C]) -> C:
        return cls()

    @classmethod
    def __init_subclass__(cls: Type[C]) -> None:
        pass

class D:
    @staticmethod
    def __new__(cls: D) -> D:  # E: The erased type of self "__main__.D" is not a supertype of its class "Type[__main__.D]"
        return cls

    @classmethod
    def __init_subclass__(cls: D) -> None:  # E: The erased type of self "__main__.D" is not a supertype of its class "Type[__main__.D]"
        pass

class E:
    @staticmethod
    def __new__(cls) -> E:
        reveal_type(cls)  # N: Revealed type is "Type[__main__.E]"
        return cls()

    @classmethod
    def __init_subclass__(cls) -> None:
        reveal_type(cls)  # N: Revealed type is "Type[__main__.E]"

[builtins fixtures/classmethod.pyi]

[case testSelfTypePropertyUnion]
from typing import Union
class A:
    @property
    def f(self: A) -> int: pass

class B:
    @property
    def f(self: B) -> int: pass
x: Union[A, B]
reveal_type(x.f)  # N: Revealed type is "builtins.int"

[builtins fixtures/property.pyi]

[case testSelfTypeProperSupertypeAttribute]
from typing import Callable, TypeVar, ClassVar
class K: pass
T = TypeVar('T', bound=K)
class A(K):
    @property
    def g(self: K) -> int: return 0
    @property
    def gt(self: T) -> T: return self
    f: ClassVar[Callable[[object], int]]
    ft: ClassVar[Callable[[T], T]]

class B(A):
    pass

reveal_type(A().g)  # N: Revealed type is "builtins.int"
reveal_type(A().gt)  # N: Revealed type is "__main__.A"
reveal_type(A().f())  # N: Revealed type is "builtins.int"
reveal_type(A().ft())  # N: Revealed type is "__main__.A"
reveal_type(B().g)  # N: Revealed type is "builtins.int"
reveal_type(B().gt)  # N: Revealed type is "__main__.B"
reveal_type(B().f())  # N: Revealed type is "builtins.int"
reveal_type(B().ft())  # N: Revealed type is "__main__.B"

[builtins fixtures/property.pyi]

[case testSelfTypeProperSupertypeAttributeTuple]
from typing import Callable, TypeVar, Tuple, ClassVar
T = TypeVar('T')
class A(Tuple[int, int]):
    @property
    def g(self: object) -> int: return 0
    @property
    def gt(self: T) -> T: return self
    f: ClassVar[Callable[[object], int]]
    ft: ClassVar[Callable[[T], T]]

class B(A):
    pass

reveal_type(A().g)  # N: Revealed type is "builtins.int"
reveal_type(A().gt)  # N: Revealed type is "Tuple[builtins.int, builtins.int, fallback=__main__.A]"
reveal_type(A().f())  # N: Revealed type is "builtins.int"
reveal_type(A().ft())  # N: Revealed type is "Tuple[builtins.int, builtins.int, fallback=__main__.A]"
reveal_type(B().g)  # N: Revealed type is "builtins.int"
reveal_type(B().gt)  # N: Revealed type is "Tuple[builtins.int, builtins.int, fallback=__main__.B]"
reveal_type(B().f())  # N: Revealed type is "builtins.int"
reveal_type(B().ft())  # N: Revealed type is "Tuple[builtins.int, builtins.int, fallback=__main__.B]"

[builtins fixtures/property.pyi]

[case testSelfTypeProperSupertypeAttributeMeta]
from typing import Callable, TypeVar, Type, ClassVar
T = TypeVar('T')
class A(type):
    @property
    def g(cls: object) -> int: return 0
    @property
    def gt(cls: T) -> T: return cls
    f: ClassVar[Callable[[object], int]]
    ft: ClassVar[Callable[[T], T]]

class B(A):
    pass

class X(metaclass=B):
    def __init__(self, x: int) -> None: pass
class Y(X): pass
X1: Type[X]
reveal_type(X.g)  # N: Revealed type is "builtins.int"
reveal_type(X.gt)  # N: Revealed type is "def (x: builtins.int) -> __main__.X"
reveal_type(X.f())  # N: Revealed type is "builtins.int"
reveal_type(X.ft())  # N: Revealed type is "def (x: builtins.int) -> __main__.X"
reveal_type(Y.g)  # N: Revealed type is "builtins.int"
reveal_type(Y.gt)  # N: Revealed type is "def (x: builtins.int) -> __main__.Y"
reveal_type(Y.f())  # N: Revealed type is "builtins.int"
reveal_type(Y.ft())  # N: Revealed type is "def (x: builtins.int) -> __main__.Y"
reveal_type(X1.g)  # N: Revealed type is "builtins.int"
reveal_type(X1.gt)  # N: Revealed type is "Type[__main__.X]"
reveal_type(X1.f())  # N: Revealed type is "builtins.int"
reveal_type(X1.ft())  # N: Revealed type is "Type[__main__.X]"

[builtins fixtures/property.pyi]

[case testSelfTypeProperSupertypeAttributeGeneric]
from typing import Callable, TypeVar, Generic, ClassVar
Q = TypeVar('Q', covariant=True)
class K(Generic[Q]):
    q: Q
T = TypeVar('T')
class A(K[Q]):
    @property
    def g(self: K[object]) -> int: return 0
    @property
    def gt(self: K[T]) -> T: return self.q
    f: ClassVar[Callable[[object], int]]
    ft: ClassVar[Callable[[T], T]]

class B(A[Q]):
    pass
a: A[int]
b: B[str]
reveal_type(a.g)  # N: Revealed type is "builtins.int"
reveal_type(a.gt)  # N: Revealed type is "builtins.int"
reveal_type(a.f())  # N: Revealed type is "builtins.int"
reveal_type(a.ft())  # N: Revealed type is "__main__.A[builtins.int]"
reveal_type(b.g)  # N: Revealed type is "builtins.int"
reveal_type(b.gt)  # N: Revealed type is "builtins.str"
reveal_type(b.f())  # N: Revealed type is "builtins.int"
reveal_type(b.ft())  # N: Revealed type is "__main__.B[builtins.str]"
[builtins fixtures/property.pyi]

[case testSelfTypeRestrictedMethod]
from typing import TypeVar, Generic

T = TypeVar('T')
class C(Generic[T]):
    def from_item(self: C[str]) -> None: ...

i: C[int]
s: C[str]

i.from_item()  # E: Invalid self argument "C[int]" to attribute function "from_item" with type "Callable[[C[str]], None]"
s.from_item()

[case testSelfTypeRestrictedClassMethod]
from typing import TypeVar, Generic, Type

T = TypeVar('T')
class C(Generic[T]):
    @classmethod
    def from_item(cls: Type[C[str]]) -> None: ...

class DI(C[int]): ...
class DS(C[str]): ...

DI().from_item()  # E: Invalid self argument "Type[DI]" to class attribute function "from_item" with type "Callable[[Type[C[str]]], None]"
DS().from_item()
DI.from_item()  # E: Invalid self argument "Type[DI]" to attribute function "from_item" with type "Callable[[Type[C[str]]], None]"
DS.from_item()
[builtins fixtures/classmethod.pyi]

[case testSelfTypeRestrictedMethodOverload]
from typing import TypeVar, Generic, overload, Tuple

T = TypeVar('T')
class C(Generic[T]):
    @overload
    def from_item(self: C[str], item: str) -> None: ...
    @overload
    def from_item(self: C[int], item: Tuple[int]) -> None: ...
    def from_item(self, item):
        ...

ci: C[int]
cs: C[str]
reveal_type(ci.from_item)  # N: Revealed type is "def (item: Tuple[builtins.int])"
reveal_type(cs.from_item)  # N: Revealed type is "def (item: builtins.str)"
[builtins fixtures/tuple.pyi]

[case testSelfTypeRestrictedMethodOverloadFallback]
from typing import TypeVar, Generic, overload, Callable

T = TypeVar('T')
class C(Generic[T]):
    @overload
    def from_item(self: C[str]) -> str: ...
    @overload
    def from_item(self, converter: Callable[[T], str]) -> str: ...
    def from_item(self, converter):
        ...

ci: C[int]
cs: C[str]
reveal_type(cs.from_item())  # N: Revealed type is "builtins.str"
ci.from_item()  # E: Missing positional argument "converter" in call to "from_item" of "C"

def conv(x: int) -> str: ...
def bad(x: str) -> str: ...
reveal_type(ci.from_item(conv))  # N: Revealed type is "builtins.str"
ci.from_item(bad)  # E: Argument 1 to "from_item" of "C" has incompatible type "Callable[[str], str]"; expected "Callable[[int], str]"

[case testSelfTypeRestrictedMethodOverloadInit]
from typing import TypeVar
from lib import P, C

reveal_type(P)  # N: Revealed type is "Overload(def [T] (use_str: Literal[True]) -> lib.P[builtins.str], def [T] (use_str: Literal[False]) -> lib.P[builtins.int])"
reveal_type(P(use_str=True))  # N: Revealed type is "lib.P[builtins.str]"
reveal_type(P(use_str=False))  # N: Revealed type is "lib.P[builtins.int]"

reveal_type(C)  # N: Revealed type is "Overload(def [T] (item: T`1, use_tuple: Literal[False]) -> lib.C[T`1], def [T] (item: T`1, use_tuple: Literal[True]) -> lib.C[builtins.tuple[T`1, ...]])"
reveal_type(C(0, use_tuple=False))  # N: Revealed type is "lib.C[builtins.int]"
reveal_type(C(0, use_tuple=True))  # N: Revealed type is "lib.C[builtins.tuple[builtins.int, ...]]"

T = TypeVar('T')
class SubP(P[T]):
    pass

SubP('no')  # E: No overload variant of "SubP" matches argument type "str" \
            # N: Possible overload variants: \
            # N:     def [T] __init__(self, use_str: Literal[True]) -> SubP[T] \
            # N:     def [T] __init__(self, use_str: Literal[False]) -> SubP[T]

# This is a bit unfortunate: we don't have a way to map the overloaded __init__ to subtype.
x = SubP(use_str=True)  # E: Need type annotation for "x"
reveal_type(x)  # N: Revealed type is "__main__.SubP[Any]"
y: SubP[str] = SubP(use_str=True)

[file lib.pyi]
from typing import TypeVar, Generic, overload, Tuple
from typing_extensions import Literal

T = TypeVar('T')
class P(Generic[T]):
    @overload
    def __init__(self: P[str], use_str: Literal[True]) -> None: ...
    @overload
    def __init__(self: P[int], use_str: Literal[False]) -> None: ...

class C(Generic[T]):
    @overload
    def __init__(self: C[T], item: T, use_tuple: Literal[False]) -> None: ...
    @overload
    def __init__(self: C[Tuple[T, ...]], item: T, use_tuple: Literal[True]) -> None: ...
[builtins fixtures/bool.pyi]

[case testSelfTypeRestrictedMethodOverloadInitFallBacks]
from lib import PFallBack, PFallBackAny

t: bool
xx = PFallBack(t)  # E: Need type annotation for "xx"
yy = PFallBackAny(t)  # OK

[file lib.pyi]
from typing import TypeVar, Generic, overload, Tuple, Any
from typing_extensions import Literal

class PFallBack(Generic[T]):
    @overload
    def __init__(self: PFallBack[str], use_str: Literal[True]) -> None: ...
    @overload
    def __init__(self: PFallBack[int], use_str: Literal[False]) -> None: ...
    @overload
    def __init__(self, use_str: bool) -> None: ...

class PFallBackAny(Generic[T]):
    @overload
    def __init__(self: PFallBackAny[str], use_str: Literal[True]) -> None: ...
    @overload
    def __init__(self: PFallBackAny[int], use_str: Literal[False]) -> None: ...
    @overload
    def __init__(self: PFallBackAny[Any], use_str: bool) -> None: ...
[builtins fixtures/bool.pyi]

[case testSelfTypeRestrictedMethodOverloadInitBadTypeNoCrash]
from lib import P
P(0)
[file lib.pyi]
from typing import overload

class P:
    @overload
    def __init__(self: Bad, x: int) -> None: ...  # E: Name "Bad" is not defined
    @overload
    def __init__(self) -> None: ...

[case testSelfTypeNarrowBinding]
from typing import TypeVar, List, Generic

T = TypeVar('T')
S = TypeVar('S')

class Base(Generic[T]):
    def get_item(self: Base[List[S]]) -> S: ...

class Sub(Base[List[int]]): ...
class BadSub(Base[int]): ...

reveal_type(Sub().get_item())  # N: Revealed type is "builtins.int"
BadSub().get_item()  # E: Invalid self argument "BadSub" to attribute function "get_item" with type "Callable[[Base[List[S]]], S]"
[builtins fixtures/list.pyi]

[case testMixinAllowedWithProtocol]
from typing import TypeVar
from typing_extensions import Protocol

class Resource(Protocol):
    def close(self) -> int: ...

class AtomicClose:
    def atomic_close(self: Resource) -> int:
        return self.close()

T = TypeVar('T', bound=Resource)
class Copyable:
    def copy(self: T) -> T: ...

class File(AtomicClose, Copyable):
    def close(self) -> int:
       ...

class Bad(AtomicClose, Copyable):
    ...

f: File
b: Bad
f.atomic_close()  # OK
b.atomic_close()  # E: Invalid self argument "Bad" to attribute function "atomic_close" with type "Callable[[Resource], int]"

reveal_type(f.copy())  # N: Revealed type is "__main__.File"
b.copy()  # E: Invalid self argument "Bad" to attribute function "copy" with type "Callable[[T], T]"
[builtins fixtures/tuple.pyi]

[case testMixinProtocolSuper]
from typing import Protocol

class Base(Protocol):
    def func(self) -> int:
        ...

class TweakFunc:
    def func(self: Base) -> int:
        return reveal_type(super().func())  # E: Call to abstract method "func" of "Base" with trivial body via super() is unsafe \
                                            # N: Revealed type is "builtins.int"

class Good:
    def func(self) -> int: ...
class C(TweakFunc, Good): pass
C().func()  # OK

class Bad:
    def func(self) -> str: ...
class CC(TweakFunc, Bad): pass  # E: Definition of "func" in base class "TweakFunc" is incompatible with definition in base class "Bad"

[case testBadClassLevelDecoratorHack]
from typing_extensions import Protocol
from typing import TypeVar, Any

class FuncLike(Protocol):
    __call__: Any
F = TypeVar('F', bound=FuncLike)

class Test:
    def _deco(func: F) -> F: ...

    @_deco
    def meth(self, x: str) -> int: ...

reveal_type(Test().meth)  # N: Revealed type is "def (x: builtins.str) -> builtins.int"
Test()._deco  # E: Invalid self argument "Test" to attribute function "_deco" with type "Callable[[F], F]"
[builtins fixtures/tuple.pyi]

[case testSelfTypeTrickyExample]
from typing import *

In = TypeVar('In')
Out = TypeVar('Out')
Mid = TypeVar('Mid')
NewOut = TypeVar('NewOut')

class Lnk(Generic[In, Out]):
    def test(self: Lnk[In, Mid], other: Lnk[Mid, NewOut]) -> Lnk[In, NewOut]: ...

class X: pass
class Y: pass
class Z: pass

a: Lnk[X, Y] = Lnk()
b: Lnk[Y, Z] = Lnk()

a.test(b)
b.test(a)  # E: Argument 1 to "test" of "Lnk" has incompatible type "Lnk[X, Y]"; expected "Lnk[Z, Y]"

[case testSelfTypeReallyTrickyExample]
from typing import *

In = TypeVar('In')
Out = TypeVar('Out')
Other = TypeVar('Other')

_1 = TypeVar('_1')
_2 = TypeVar('_2')
__1 = TypeVar('__1')
__2 = TypeVar('__2')

class Lnk(Generic[In, Out]):
    @overload
    def __rshift__(self, other: Lnk[Out, Other]) -> Lnk[In,Other]: ...
    @overload
    def __rshift__(self: Lnk[In, Tuple[_1, _2]],
                   other: Tuple[Lnk[_1, __1], Lnk[_2, __2]]) -> Lnk[In, Tuple[__1, __2]]: ...
    def __rshift__(self: Any, other: Any) -> Any:
        ...

a: Lnk[str, Tuple[str, int]] = Lnk()
b: Lnk[str, int] = Lnk()
c: Lnk[int, float] = Lnk()

d: Lnk[str, float] = b >> c  # OK
e: Lnk[str, Tuple[int, float]] = a >> (b, c)  # OK
f: Lnk[str, Tuple[float, int]] = a >> (c, b) # E: Unsupported operand types for >> ("Lnk[str, Tuple[str, int]]" and "Tuple[Lnk[int, float], Lnk[str, int]]")
[builtins fixtures/tuple.pyi]

[case testSelfTypeMutuallyExclusiveRestrictions]
from typing import Generic, TypeVar

T = TypeVar('T')

class Foo(Generic[T]):
    def f1(self: Foo[str]) -> None:
        self.f2()  # E: Invalid self argument "Foo[str]" to attribute function "f2" with type "Callable[[Foo[int]], None]"
    def f2(self: Foo[int]) -> None:
        self.f1()  # E: Invalid self argument "Foo[int]" to attribute function "f1" with type "Callable[[Foo[str]], None]"

[case testSelfTypeStructureMetaclassMatch]
from typing import TypeVar, Type, Generic, cast

Cls = TypeVar('Cls')
T = TypeVar('T')

class Manager(Generic[Cls]):
    def create(self: Manager[Type[T]]) -> T: ...

class ModelMeta(type):
    @property
    def objects(cls: T) -> Manager[T]: ...

class Model(metaclass=ModelMeta):
    pass

class Dog(Model): ...
class Cat(Model): ...

c: Cat = Dog.objects.create()  # E: Incompatible types in assignment (expression has type "Dog", variable has type "Cat")
d: Dog = Dog.objects.create()
[builtins fixtures/property.pyi]

[case testSelfTypeProtocolMetaclassMatch]
from typing import Type, TypeVar, Protocol

class HasX(Protocol):
    x: int

T = TypeVar('T', bound=HasX)

class Meta(type):
    def do_x(cls: Type[T]) -> T:
        cls.x
        return cls()

class Good(metaclass=Meta):
    x: int
class Bad(metaclass=Meta):
    pass

Good.do_x()
Bad.do_x()  # E: Invalid self argument "Type[Bad]" to attribute function "do_x" with type "Callable[[Type[T]], T]"

[case testSelfTypeProtocolClassmethodMatch]
from typing import Type, TypeVar, Protocol

T = TypeVar('T')

class HasDoX(Protocol):
    @classmethod
    def do_x(cls: Type[T]) -> T:
        ...

class Good:
    @classmethod
    def do_x(cls) -> 'Good':
        ...

class Bad:
    @classmethod
    def do_x(cls) -> Good:
        ...

good: HasDoX = Good()
bad: HasDoX = Bad()
[builtins fixtures/classmethod.pyi]
[out]
main:21: error: Incompatible types in assignment (expression has type "Bad", variable has type "HasDoX")
main:21: note: Following member(s) of "Bad" have conflicts:
main:21: note:     Expected:
main:21: note:         def do_x(cls) -> Bad
main:21: note:     Got:
main:21: note:         def do_x(cls) -> Good

[case testSelfTypeNotSelfType]
# Friendlier error messages for common mistakes. See #2950
class A:
    def f(x: int) -> None: ...
    def g(self: None) -> None: ...
[out]
main:3: error: Self argument missing for a non-static method (or an invalid type for self)
main:4: error: The erased type of self "None" is not a supertype of its class "__main__.A"

[case testUnionPropertyField]
from typing import Union

class A:
    x: int

class B:
    @property
    def x(self) -> int: return 1

class C:
    @property
    def x(self) -> int: return 1

ab: Union[A, B, C]
reveal_type(ab.x)  # N: Revealed type is "builtins.int"
[builtins fixtures/property.pyi]

[case testSelfTypeNoTypeVars]
from typing import Generic, List, Optional, TypeVar, Any

Q = TypeVar("Q")
T = TypeVar("T", bound='Super[Any]')

class Super(Generic[Q]):
    @classmethod
    def meth(cls, arg: List[T]) -> List[T]:
        pass

class Sub(Super[int]): ...

def test(x: List[Sub]) -> None:
    reveal_type(Sub.meth(x))  # N: Revealed type is "builtins.list[__main__.Sub]"
[builtins fixtures/isinstancelist.pyi]

[case testSelfTypeNoTypeVarsRestrict]
from typing import Generic, TypeVar

T = TypeVar('T')
S = TypeVar('S')

class C(Generic[T]):
    def limited(self: C[str], arg: S) -> S: ...

reveal_type(C[str]().limited(0))  # N: Revealed type is "builtins.int"

[case testSelfTypeMultipleTypeVars]
from typing import Generic, TypeVar, Tuple

T = TypeVar('T')
S = TypeVar('S')
U = TypeVar('U')
V = TypeVar('V')

class C(Generic[T]):
    def magic(self: C[Tuple[S, U]]) -> Tuple[T, S, U]: ...

class D(Generic[V]):
    def f(self) -> None:
        reveal_type(C[Tuple[V, str]]().magic())  # N: Revealed type is "Tuple[Tuple[V`1, builtins.str], V`1, builtins.str]"
[builtins fixtures/tuple.pyi]

[case testSelfTypeOnUnion]
from typing import TypeVar, Union

T = TypeVar('T')

class A:
    same: int

class C:
    def same(self: T) -> T: ...

x: Union[A, C]
reveal_type(x.same)  # N: Revealed type is "Union[builtins.int, def () -> __main__.C]"

[case testSelfTypeOnUnionClassMethod]
from typing import TypeVar, Union, Type

T = TypeVar('T')

class A:
    same: int

class C:
    @classmethod
    def same(cls: Type[T]) -> T: ...

x: Union[A, C]
reveal_type(x.same)  # N: Revealed type is "Union[builtins.int, def () -> __main__.C]"
[builtins fixtures/classmethod.pyi]

[case SelfTypeOverloadedClassMethod]
from lib import Base
from typing import overload, Tuple

class Sub(Base):
    @overload
    @classmethod
    def make(cls) -> Sub: ...
    @overload
    @classmethod
    def make(cls, num: int) -> Tuple[Sub, ...]: ...
    @classmethod
    def make(cls, num=1):
        ...

class Other(Base): ...
class Double(Sub): ...

reveal_type(Other.make())  # N: Revealed type is "__main__.Other"
reveal_type(Other.make(3))  # N: Revealed type is "builtins.tuple[__main__.Other, ...]"
reveal_type(Double.make())  # N: Revealed type is "__main__.Sub"
reveal_type(Double.make(3))  # N: Revealed type is "builtins.tuple[__main__.Sub, ...]"
[file lib.pyi]
from typing import overload, TypeVar, Type, Tuple

T = TypeVar('T', bound=Base)

class Base:
    @overload
    @classmethod
    def make(cls: Type[T]) -> T: ...
    @overload
    @classmethod
    def make(cls: Type[T], num: int) -> Tuple[T, ...]: ...
[builtins fixtures/classmethod.pyi]

[case testSelfTypeClassMethodOnUnion]
from typing import Type, Union, TypeVar

T = TypeVar('T')

class A:
    @classmethod
    def meth(cls: Type[T]) -> T: ...
class B(A): ...
class C(A): ...

t: Type[Union[B, C]]
reveal_type(t.meth)  # N: Revealed type is "Union[def () -> __main__.B, def () -> __main__.C]"
x = t.meth()
reveal_type(x)  # N: Revealed type is "Union[__main__.B, __main__.C]"
[builtins fixtures/classmethod.pyi]

[case testSelfTypeClassMethodOnUnionGeneric]
from typing import Type, Union, TypeVar, Generic

T = TypeVar('T')
S = TypeVar('S')

class A(Generic[T]):
    @classmethod
    def meth(cls: Type[S]) -> S: ...

t: Type[Union[A[int], A[str]]]
x = t.meth()
reveal_type(x)  # N: Revealed type is "Union[__main__.A[builtins.int], __main__.A[builtins.str]]"
[builtins fixtures/classmethod.pyi]

[case testSelfTypeClassMethodOnUnionList]
from typing import Type, Union, TypeVar, List

T = TypeVar('T')

class A:
    @classmethod
    def meth(cls: Type[T]) -> List[T]: ...
class B(A): ...
class C(A): ...

t: Type[Union[B, C]]
x = t.meth()[0]
reveal_type(x)  # N: Revealed type is "Union[__main__.B, __main__.C]"
[builtins fixtures/isinstancelist.pyi]

[case testSelfTypeClassMethodOverloadedOnInstance]
from typing import Optional, Type, TypeVar, overload, Union

Id = int

A = TypeVar("A", bound='AClass')

class AClass:
    @overload
    @classmethod
    def delete(cls: Type[A], id: Id, id2: Id) -> Optional[int]: ...

    @overload
    @classmethod
    def delete(cls: Type[A], id: A, id2: None = None) -> Optional[int]: ...

    @classmethod
    def delete(cls: Type[A], id: Union[A, Id], id2: Optional[Id] = None) -> Optional[int]:
        ...

def foo(x: Type[AClass]) -> None:
    reveal_type(x.delete)  # N: Revealed type is "Overload(def (id: builtins.int, id2: builtins.int) -> Union[builtins.int, None], def (id: __main__.AClass, id2: None =) -> Union[builtins.int, None])"
    y = x()
    reveal_type(y.delete)  # N: Revealed type is "Overload(def (id: builtins.int, id2: builtins.int) -> Union[builtins.int, None], def (id: __main__.AClass, id2: None =) -> Union[builtins.int, None])"
    y.delete(10, 20)
    y.delete(y)

def bar(x: AClass) -> None:
    reveal_type(x.delete)  # N: Revealed type is "Overload(def (id: builtins.int, id2: builtins.int) -> Union[builtins.int, None], def (id: __main__.AClass, id2: None =) -> Union[builtins.int, None])"
    x.delete(10, 20)
[builtins fixtures/classmethod.pyi]

[case testSelfTypeBadTypeIgnoredInConstructor]
class Base: ...
class Sub(Base):
    def __init__(self: Base) -> None: ...

reveal_type(Sub())  # N: Revealed type is "__main__.Sub"

[case testSelfTypeBadTypeIgnoredInConstructorGeneric]
from typing import Generic, TypeVar

T = TypeVar('T')

class Base(Generic[T]): ...
class Sub(Base[T]):
    def __init__(self: Base[T], item: T) -> None: ...

reveal_type(Sub(42))  # N: Revealed type is "__main__.Sub[builtins.int]"

[case testSelfTypeBadTypeIgnoredInConstructorOverload]
from typing import overload

class Base: ...
class Sub(Base):
    @overload
    def __init__(self: Sub, item: int) -> None: ...
    @overload
    def __init__(self: Base) -> None: ...
    def __init__(self, item=None):
        ...

reveal_type(Sub)  # N: Revealed type is "Overload(def (item: builtins.int) -> __main__.Sub, def () -> __main__.Sub)"

[case testSelfTypeBadTypeIgnoredInConstructorAbstract]
from abc import abstractmethod
from typing import Protocol

class Blah(Protocol):
    @abstractmethod
    def something(self) -> None: ...

class Concrete(Blah):
    def __init__(self: Blah) -> None: ...
    def something(self) -> None: ...

Concrete()  # OK

[case testSelfTypeGenericClassNoClashInstanceMethod]
from typing import TypeVar, Generic

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

class Descriptor(Generic[M]): ...

class BaseWrapper(Generic[M]):
    def create_wrapper(self: T, metric_descriptor: Descriptor[M]) -> T: ...
class SubWrapper(BaseWrapper[M]): ...

def build_wrapper(descriptor: Descriptor[M]) -> BaseWrapper[M]:
    wrapper: BaseWrapper[M]
    return wrapper.create_wrapper(descriptor)

def build_sub_wrapper(descriptor: Descriptor[S]) -> SubWrapper[S]:
    wrapper: SubWrapper[S]
    x = wrapper.create_wrapper(descriptor)
    reveal_type(x)  # N: Revealed type is "__main__.SubWrapper[S`-1]"
    return x

[case testSelfTypeGenericClassNoClashClassMethod]
from typing import TypeVar, Generic, Type

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

class Descriptor(Generic[M]): ...

class BaseWrapper(Generic[M]):
    @classmethod
    def create_wrapper(cls: Type[T], metric_descriptor: Descriptor[M]) -> T: ...
class SubWrapper(BaseWrapper[M]): ...

def build_wrapper(descriptor: Descriptor[M]) -> BaseWrapper[M]:
    wrapper_cls: Type[BaseWrapper[M]]
    return wrapper_cls.create_wrapper(descriptor)

def build_sub_wrapper(descriptor: Descriptor[S]) -> SubWrapper[S]:
    wrapper_cls: Type[SubWrapper[S]]
    x = wrapper_cls.create_wrapper(descriptor)
    reveal_type(x)  # N: Revealed type is "__main__.SubWrapper[S`-1]"
    return x
[builtins fixtures/classmethod.pyi]

[case testSelfTypeGenericClassNoClashClassMethodClassObject]
from typing import TypeVar, Generic, Type

M = TypeVar("M")
T = TypeVar("T")

class Descriptor(Generic[M]): ...

class BaseWrapper(Generic[M]):
    @classmethod
    def create_wrapper(cls: Type[T], metric_descriptor: Descriptor[M]) -> T: ...
class SubWrapper(BaseWrapper[M]): ...

def build_wrapper(descriptor: Descriptor[M]) -> BaseWrapper[M]:
    return BaseWrapper.create_wrapper(descriptor)

def build_sub_wrapper(descriptor: Descriptor[M]) -> SubWrapper[M]:
    x = SubWrapper.create_wrapper(descriptor)
    reveal_type(x)  # N: Revealed type is "__main__.SubWrapper[M`-1]"
    return x

def build_wrapper_non_gen(descriptor: Descriptor[int]) -> BaseWrapper[str]:
    return BaseWrapper.create_wrapper(descriptor)  # E: Argument 1 to "create_wrapper" of "BaseWrapper" has incompatible type "Descriptor[int]"; expected "Descriptor[str]"

def build_sub_wrapper_non_gen(descriptor: Descriptor[int]) -> SubWrapper[str]:
    return SubWrapper.create_wrapper(descriptor)  # E: Argument 1 to "create_wrapper" of "BaseWrapper" has incompatible type "Descriptor[int]"; expected "Descriptor[str]"
[builtins fixtures/classmethod.pyi]

[case testSelfTypeInGenericClassUsedFromAnotherGenericClass1]
from typing import TypeVar, Generic, Iterator, List, Tuple

_T_co = TypeVar("_T_co", covariant=True)
_T1 = TypeVar("_T1")
_T2 = TypeVar("_T2")
S = TypeVar("S")

class Z(Iterator[_T_co]):
    def __new__(cls,
                __iter1: List[_T1],
                __iter2: List[_T2]) -> Z[Tuple[_T1, _T2]]: ...
    def __iter__(self: S) -> S: ...
    def __next__(self) -> _T_co: ...

T = TypeVar('T')

class C(Generic[T]):
    a: List[T]
    b: List[str]

    def f(self) -> None:
        for x, y in Z(self.a, self.b):
            reveal_type((x, y))  # N: Revealed type is "Tuple[T`1, builtins.str]"
[builtins fixtures/tuple.pyi]

[case testEnumerateReturningSelfFromIter]
from typing import Generic, Iterable, Iterator, TypeVar, Tuple

T = TypeVar("T")
KT = TypeVar("KT")
VT = TypeVar("VT")
Self = TypeVar("Self")

class enumerate(Iterator[Tuple[int, T]], Generic[T]):
    def __init__(self, iterable: Iterable[T]) -> None: ...
    def __iter__(self: Self) -> Self: ...
    def __next__(self) -> Tuple[int, T]: ...

class Dict(Generic[KT, VT]):
    def update(self, __m: Iterable[Tuple[KT, VT]]) -> None: ...

class ThingCollection(Generic[T]):
    collection: Iterable[Tuple[float, T]]
    index: Dict[int, T]

    def do_thing(self) -> None:
        self.index.update((idx, c) for idx, (k, c) in enumerate(self.collection))
[builtins fixtures/tuple.pyi]

[case testDequeReturningSelfFromCopy]
# Tests a bug with generic self types identified in issue #12641
from typing import Generic, Sequence, TypeVar

T = TypeVar("T")
Self = TypeVar("Self")

class deque(Sequence[T]):
    def copy(self: Self) -> Self: ...

class List(Sequence[T]): ...

class Test(Generic[T]):
    def test(self) -> None:
        a: deque[List[T]]
        # previously this failed with 'Incompatible types in assignment (expression has type "deque[List[List[T]]]", variable has type "deque[List[T]]")'
        b: deque[List[T]] = a.copy()

[case testTypingSelfBasic]
from typing import Self, List

class C:
    attr: List[Self]
    def meth(self) -> List[Self]: ...
    def test(self) -> Self:
        if bool():
            return C()  # E: Incompatible return value type (got "C", expected "Self")
        else:
            return self
class D(C): ...

reveal_type(C.meth)  # N: Revealed type is "def [Self <: __main__.C] (self: Self`1) -> builtins.list[Self`1]"
C.attr  # E: Access to generic instance variables via class is ambiguous
reveal_type(D().meth())  # N: Revealed type is "builtins.list[__main__.D]"
reveal_type(D().attr)  # N: Revealed type is "builtins.list[__main__.D]"

[case testTypingSelfInvalidLocations]
from typing import Self, Callable

var: Self  # E: Self type is only allowed in annotations within class definition
reveal_type(var)  # N: Revealed type is "Any"

def foo() -> Self: ...  # E: Self type is only allowed in annotations within class definition
reveal_type(foo)  # N: Revealed type is "def () -> Any"

bad: Callable[[Self], Self]  # E: Self type is only allowed in annotations within class definition
reveal_type(bad)  # N: Revealed type is "def (Any) -> Any"

def func() -> None:
    var: Self  # E: Self type is only allowed in annotations within class definition

class C(Self): ...  # E: Self type is only allowed in annotations within class definition

[case testTypingSelfInvalidArgs]
from typing import Self, List

class C:
    x: Self[int]  # E: Self type cannot have type arguments
    def meth(self) -> List[Self[int]]:  # E: Self type cannot have type arguments
        ...

[case testTypingSelfConflict]
from typing import Self, TypeVar, Tuple

T = TypeVar("T")
class C:
    def meth(self: T) -> Tuple[Self, T]: ...  # E: Method cannot have explicit self annotation and Self type
reveal_type(C().meth())  # N: Revealed type is "Tuple[Never, __main__.C]"
[builtins fixtures/property.pyi]

[case testTypingSelfProperty]
from typing import Self, Tuple
class C:
    @property
    def attr(self) -> Tuple[Self, ...]: ...
class D(C): ...

reveal_type(D().attr)  # N: Revealed type is "builtins.tuple[__main__.D, ...]"
[builtins fixtures/property.pyi]

[case testTypingSelfCallableVar]
from typing import Self, Callable

class C:
    x: Callable[[Self], Self]
    def meth(self) -> Callable[[Self], Self]: ...
class D(C): ...

reveal_type(C().x)  # N: Revealed type is "def (__main__.C) -> __main__.C"
reveal_type(D().x)  # N: Revealed type is "def (__main__.D) -> __main__.D"
reveal_type(D().meth())  # N: Revealed type is "def (__main__.D) -> __main__.D"

[case testTypingSelfClassMethod]
from typing import Self

class C:
    @classmethod
    def meth(cls) -> Self: ...
    @staticmethod
    def bad() -> Self: ...  # E: Static methods cannot use Self type \
        # E: A function returning TypeVar should receive at least one argument containing the same TypeVar \
        # N: Consider using the upper bound "C" instead

class D(C): ...
reveal_type(D.meth())  # N: Revealed type is "__main__.D"
reveal_type(D.bad())  # N: Revealed type is "Never"
[builtins fixtures/classmethod.pyi]

[case testTypingSelfOverload]
from typing import Self, overload, Union

class C:
    @overload
    def foo(self, other: Self) -> Self: ...
    @overload
    def foo(self, other: int) -> int: ...
    def foo(self, other: Union[Self, int]) -> Union[Self, int]:
        return other
class D(C): ...
reveal_type(D().foo)  # N: Revealed type is "Overload(def (other: __main__.D) -> __main__.D, def (other: builtins.int) -> builtins.int)"

[case testTypingSelfNestedInAlias]
from typing import Generic, Self, TypeVar, List, Tuple

T = TypeVar("T")
Pairs = List[Tuple[T, T]]

class C(Generic[T]):
    def pairs(self) -> Pairs[Self]: ...
class D(C[T]): ...
reveal_type(D[int]().pairs())  # N: Revealed type is "builtins.list[Tuple[__main__.D[builtins.int], __main__.D[builtins.int]]]"
[builtins fixtures/tuple.pyi]

[case testTypingSelfOverrideVar]
from typing import Self, TypeVar, Generic

T = TypeVar("T")
class C(Generic[T]):
    x: Self

class D(C[int]):
    x: D
class Bad(C[int]):
    x: C[int]  # E: Incompatible types in assignment (expression has type "C[int]", base class "C" defined the type as "Bad")

[case testTypingSelfOverrideVarMulti]
from typing import Self

class C:
    x: Self
class D:
    x: C
class E:
    x: Good

class Bad(D, C):  # E: Definition of "x" in base class "D" is incompatible with definition in base class "C"
    ...
class Good(E, C):
    ...

[case testTypingSelfAlternativeGenericConstructor]
from typing import Self, Generic, TypeVar, Tuple

T = TypeVar("T")
class C(Generic[T]):
    def __init__(self, val: T) -> None: ...
    @classmethod
    def pair(cls, val: T) -> Tuple[Self, Self]:
        return (cls(val), C(val))  # E: Incompatible return value type (got "Tuple[Self, C[T]]", expected "Tuple[Self, Self]")

class D(C[int]): pass
reveal_type(C.pair(42))  # N: Revealed type is "Tuple[__main__.C[builtins.int], __main__.C[builtins.int]]"
reveal_type(D.pair("no"))  # N: Revealed type is "Tuple[__main__.D, __main__.D]" \
    # E: Argument 1 to "pair" of "C" has incompatible type "str"; expected "int"
[builtins fixtures/classmethod.pyi]

[case testTypingSelfMixedTypeVars]
from typing import Self, TypeVar, Generic, Tuple

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

class C(Generic[T]):
    def meth(self, arg: S) -> Tuple[Self, S, T]: ...

class D(C[int]): ...

c: C[int]
d: D
reveal_type(c.meth("test"))  # N: Revealed type is "Tuple[__main__.C[builtins.int], builtins.str, builtins.int]"
reveal_type(d.meth("test"))  # N: Revealed type is "Tuple[__main__.D, builtins.str, builtins.int]"
[builtins fixtures/tuple.pyi]

[case testTypingSelfRecursiveInit]
from typing import Self

class C:
    def __init__(self, other: Self) -> None: ...
class D(C): ...

reveal_type(C)  # N: Revealed type is "def (other: __main__.C) -> __main__.C"
reveal_type(D)  # N: Revealed type is "def (other: __main__.D) -> __main__.D"

[case testTypingSelfCorrectName]
from typing import Self, List

class C:
    Self = List[C]
    def meth(self) -> Self: ...
reveal_type(C.meth)  # N: Revealed type is "def (self: __main__.C) -> builtins.list[__main__.C]"

[case testTypingSelfClassVar]
from typing import Self, ClassVar, Generic, TypeVar

class C:
    DEFAULT: ClassVar[Self]
reveal_type(C.DEFAULT)  # N: Revealed type is "__main__.C"

T = TypeVar("T")
class G(Generic[T]):
    BAD: ClassVar[Self]  # E: ClassVar cannot contain Self type in generic classes
reveal_type(G.BAD)  # N: Revealed type is "__main__.G[Any]"

[case testTypingSelfMetaClassDisabled]
from typing import Self

class Meta(type):
    def meth(cls) -> Self: ...  # E: Self type cannot be used in a metaclass

[case testTypingSelfNonAnnotationUses]
from typing import Self, List, cast

class C:
    A = List[Self]  # E: Self type cannot be used in type alias target
    B = cast(Self, ...)
    def meth(self) -> A: ...

class D(C): ...
reveal_type(D().meth())  # N: Revealed type is "builtins.list[Any]"
reveal_type(D().B)  # N: Revealed type is "__main__.D"

[case testTypingSelfInternalSafe]
from typing import Self

class C:
    x: Self
    def __init__(self, x: C) -> None:
        self.x = x  # E: Incompatible types in assignment (expression has type "C", variable has type "Self")

[case testTypingSelfRedundantAllowed]
from typing import Self, Type

class C:
    def f(self: Self) -> Self:
        d: Defer
        class Defer: ...
        return self

    @classmethod
    def g(cls: Type[Self]) -> Self:
        d: DeferAgain
        class DeferAgain: ...
        return cls()
[builtins fixtures/classmethod.pyi]

[case testTypingSelfRedundantAllowed_pep585]
# flags: --python-version 3.9
from typing import Self

class C:
    def f(self: Self) -> Self:
        d: Defer
        class Defer: ...
        return self

    @classmethod
    def g(cls: type[Self]) -> Self:
        d: DeferAgain
        class DeferAgain: ...
        return cls()
[builtins fixtures/classmethod.pyi]

[case testTypingSelfRedundantWarning]
# mypy: enable-error-code="redundant-self"

from typing import Self, Type

class C:
    def copy(self: Self) -> Self:  # E: Redundant "Self" annotation for the first method argument
        d: Defer
        class Defer: ...
        return self

    @classmethod
    def g(cls: Type[Self]) -> Self:  # E: Redundant "Self" annotation for the first method argument
        d: DeferAgain
        class DeferAgain: ...
        return cls()
[builtins fixtures/classmethod.pyi]

[case testTypingSelfRedundantWarning_pep585]
# flags: --python-version 3.9
# mypy: enable-error-code="redundant-self"

from typing import Self

class C:
    def copy(self: Self) -> Self:  # E: Redundant "Self" annotation for the first method argument
        d: Defer
        class Defer: ...
        return self

    @classmethod
    def g(cls: type[Self]) -> Self:  # E: Redundant "Self" annotation for the first method argument
        d: DeferAgain
        class DeferAgain: ...
        return cls()
[builtins fixtures/classmethod.pyi]

[case testTypingSelfAssertType]
from typing import Self, assert_type

class C:
    def foo(self) -> None:
        assert_type(self, Self)  # E: Expression is of type "C", not "Self"
        assert_type(C(), Self)  # E: Expression is of type "C", not "Self"

    def bar(self) -> Self:
        assert_type(self, Self)  # OK
        assert_type(C(), Self)  # E: Expression is of type "C", not "Self"
        return self

[case testTypingSelfTypeVarClash]
from typing import Self, TypeVar, Tuple

S = TypeVar("S")
class C:
    def bar(self) -> Self: ...
    def foo(self, x: S) -> Tuple[Self, S]: ...

reveal_type(C.foo)  # N: Revealed type is "def [Self <: __main__.C, S] (self: Self`1, x: S`2) -> Tuple[Self`1, S`2]"
reveal_type(C().foo(42))  # N: Revealed type is "Tuple[__main__.C, builtins.int]"
[builtins fixtures/tuple.pyi]

[case testTypingSelfTypeVarClashAttr]
from typing import Self, TypeVar, Tuple, Callable

class Defer(This): ...

S = TypeVar("S")
class C:
    def bar(self) -> Self: ...
    foo: Callable[[S, Self], Tuple[Self, S]]

reveal_type(C().foo)  # N: Revealed type is "def [S] (S`1, __main__.C) -> Tuple[__main__.C, S`1]"
reveal_type(C().foo(42, C()))  # N: Revealed type is "Tuple[__main__.C, builtins.int]"
class This: ...
[builtins fixtures/tuple.pyi]

[case testTypingSelfAttrOldVsNewStyle]
from typing import Self, TypeVar

T = TypeVar("T", bound='C')
class C:
    x: Self
    def foo(self: T) -> T:
        return self.x
    def bar(self: T) -> T:
        self.x = self
        return self
    def baz(self: Self) -> None:
        self.x = self
    def bad(self) -> None:
        # This is unfortunate, but required by PEP 484
        self.x = self  # E: Incompatible types in assignment (expression has type "C", variable has type "Self")

[case testTypingSelfClashInBodies]
from typing import Self, TypeVar

T = TypeVar("T")
class C:
    def very_bad(self, x: T) -> None:
        self.x = x  # E: Incompatible types in assignment (expression has type "T", variable has type "Self")
    x: Self
    def baz(self: Self, x: T) -> None:
        y: T = x

[case testTypingSelfClashUnrelated]
from typing import Self, Generic, TypeVar

class B: ...

T = TypeVar("T", bound=B)
class C(Generic[T]):
    def __init__(self, val: T) -> None:
        self.val = val
    def foo(self) -> Self: ...

def test(x: C[T]) -> T:
    reveal_type(x.val)  # N: Revealed type is "T`-1"
    return x.val

[case testTypingSelfGenericBound]
from typing import Self, Generic, TypeVar

T = TypeVar("T")
class C(Generic[T]):
    val: T
    def foo(self) -> Self:
        reveal_type(self.val)  # N: Revealed type is "T`1"
        return self

[case testTypingSelfDifferentImport]
import typing as t

class Foo:
    def foo(self) -> t.Self:
        return self
    @classmethod
    def bar(cls) -> t.Self:
        return cls()
[builtins fixtures/classmethod.pyi]

[case testTypingSelfAllowAliasUseInFinalClasses]
from typing import Self, final

@final
class C:
    def meth(self) -> Self:
        return C()  # OK for final classes

[case testTypingSelfCallableClassVar]
from typing import Self, ClassVar, Callable, TypeVar

class C:
    f: ClassVar[Callable[[Self], Self]]
class D(C): ...

reveal_type(D.f)  # N: Revealed type is "def (__main__.D) -> __main__.D"
reveal_type(D().f)  # N: Revealed type is "def () -> __main__.D"

[case testSelfTypeCallableClassVarOldStyle]
from typing import ClassVar, Callable, TypeVar

T = TypeVar("T")
class C:
    f: ClassVar[Callable[[T], T]]

class D(C): ...

reveal_type(D.f)  # N: Revealed type is "def [T] (T`1) -> T`1"
reveal_type(D().f)  # N: Revealed type is "def () -> __main__.D"

[case testTypingSelfOnSuperTypeVarValues]
from typing import Self, Generic, TypeVar

T = TypeVar("T", int, str)

class B:
    def copy(self) -> Self: ...
class C(B, Generic[T]):
    def copy(self) -> Self:
        inst = super().copy()
        reveal_type(inst)  # N: Revealed type is "Self`0"
        return inst

[case testTypingSelfWithValuesExpansion]
from typing import Self, Generic, TypeVar

class A: pass
class B: pass
T = TypeVar("T", A, B)

class C(Generic[T]):
    val: T
    def foo(self, x: T) -> None: ...
    def bar(self, x: T) -> Self:
        reveal_type(self.foo)  # N: Revealed type is "def (x: __main__.A)" \
                               # N: Revealed type is "def (x: __main__.B)"
        self.foo(x)
        return self
    def baz(self: Self, x: T) -> None:
        reveal_type(self.val)  # N: Revealed type is "__main__.A" \
                               # N: Revealed type is "__main__.B"
        self.val = x

[case testNarrowSelfType]
from typing import Self, Union

class A: ...
class B:
    def f1(self, v: Union[Self, A]) -> A:
        if isinstance(v, B):
            return A()
        else:
            return v
    def f2(self, v: Union[Self, A]) -> A:
        if isinstance(v, B):
            return A()
        else:
            return B()  # E: Incompatible return value type (got "B", expected "A")

[builtins fixtures/isinstancelist.pyi]

[case testAttributeOnSelfAttributeInSubclass]
from typing import List, Self

class A:
    x: Self
    xs: List[Self]

class B(A):
    extra: int

    def meth(self) -> None:
        reveal_type(self.x)  # N: Revealed type is "Self`0"
        reveal_type(self.xs[0])  # N: Revealed type is "Self`0"
        reveal_type(self.x.extra)  # N: Revealed type is "builtins.int"
        reveal_type(self.xs[0].extra)  # N: Revealed type is "builtins.int"
[builtins fixtures/list.pyi]

[case testSelfTypesWithParamSpecExtract]
from typing import Any, Callable, Generic, TypeVar
from typing_extensions import ParamSpec

P = ParamSpec("P")
F = TypeVar("F", bound=Callable[..., Any])
class Example(Generic[F]):
    def __init__(self, fn: F) -> None:
        ...
    def __call__(self: Example[Callable[P, Any]], *args: P.args, **kwargs: P.kwargs) -> None:
        ...

def test_fn(a: int, b: str) -> None:
    ...

example = Example(test_fn)
example()  # E: Missing positional arguments "a", "b" in call to "__call__" of "Example"
example(1, "b")  # OK
[builtins fixtures/list.pyi]

[case testSelfTypesWithParamSpecInfer]
from typing import TypeVar, Protocol, Type, Callable
from typing_extensions import ParamSpec

R = TypeVar("R", covariant=True)
P = ParamSpec("P")
class AsyncP(Protocol[P]):
    def meth(self, *args: P.args, **kwargs: P.kwargs) -> None:
        ...

class Async:
    @classmethod
    def async_func(cls: Type[AsyncP[P]]) -> Callable[P, int]:
        ...

class Add(Async):
    def meth(self, x: int, y: int) -> None: ...

reveal_type(Add.async_func())  # N: Revealed type is "def (x: builtins.int, y: builtins.int) -> builtins.int"
reveal_type(Add().async_func())  # N: Revealed type is "def (x: builtins.int, y: builtins.int) -> builtins.int"
[builtins fixtures/classmethod.pyi]

[case testSelfTypeMethodOnClassObject]
from typing import Self

class Object:  # Needed to mimic object in typeshed
    ref: Self

class Foo:
    def foo(self) -> Self:
        return self

class Ben(Object):
    MY_MAP = {
        "foo": Foo.foo,
    }
    @classmethod
    def doit(cls) -> Foo:
        reveal_type(cls.MY_MAP)  # N: Revealed type is "builtins.dict[builtins.str, def [Self <: __main__.Foo] (self: Self`4) -> Self`4]"
        foo_method = cls.MY_MAP["foo"]
        return foo_method(Foo())
[builtins fixtures/isinstancelist.pyi]

[case testSelfTypeOnGenericClassObjectNewStyleBound]
from typing import Generic, TypeVar, Self

T = TypeVar("T")
S = TypeVar("S")
class B(Generic[T, S]):
    def copy(self) -> Self: ...

b: B[int, str]
reveal_type(B.copy(b))  # N: Revealed type is "__main__.B[builtins.int, builtins.str]"

class C(B[T, S]): ...

c: C[int, str]
reveal_type(C.copy(c))  # N: Revealed type is "__main__.C[builtins.int, builtins.str]"

B.copy(42)  # E: Value of type variable "Self" of "copy" of "B" cannot be "int"
C.copy(42)  # E: Value of type variable "Self" of "copy" of "B" cannot be "int"
[builtins fixtures/tuple.pyi]

[case testRecursiveSelfTypeCallMethodNoCrash]
from typing import Callable, TypeVar

T = TypeVar("T")
class Partial:
    def __call__(self: Callable[..., T]) -> T: ...

class Partial2:
    def __call__(self: Callable[..., T], x: T) -> T: ...

p: Partial
reveal_type(p())  # N: Revealed type is "Never"
p2: Partial2
reveal_type(p2(42))  # N: Revealed type is "builtins.int"

[case testAccessingSelfClassVarInClassMethod]
from typing import Self, ClassVar, Type, TypeVar

T = TypeVar("T", bound="Foo")

class Foo:
    instance: ClassVar[Self]
    @classmethod
    def get_instance(cls) -> Self:
        return reveal_type(cls.instance)  # N: Revealed type is "Self`0"
    @classmethod
    def get_instance_old(cls: Type[T]) -> T:
        return reveal_type(cls.instance)  # N: Revealed type is "T`-1"

class Bar(Foo):
    extra: int

    @classmethod
    def get_instance(cls) -> Self:
        reveal_type(cls.instance.extra)  # N: Revealed type is "builtins.int"
        return cls.instance

    @classmethod
    def other(cls) -> None:
        reveal_type(cls.instance)  # N: Revealed type is "Self`0"
        reveal_type(cls.instance.extra)  # N: Revealed type is "builtins.int"

reveal_type(Bar.instance)  # N: Revealed type is "__main__.Bar"
[builtins fixtures/classmethod.pyi]

[case testAccessingSelfClassVarInClassMethodTuple]
from typing import Self, ClassVar, Tuple

class C(Tuple[int, str]):
    x: Self
    y: ClassVar[Self]

    @classmethod
    def bar(cls) -> None:
        reveal_type(cls.y)  # N: Revealed type is "Self`0"
    @classmethod
    def bar_self(self) -> Self:
        return reveal_type(self.y)  # N: Revealed type is "Self`0"

c: C
reveal_type(c.x)  # N: Revealed type is "Tuple[builtins.int, builtins.str, fallback=__main__.C]"
reveal_type(c.y)  # N: Revealed type is "Tuple[builtins.int, builtins.str, fallback=__main__.C]"
reveal_type(C.y)  # N: Revealed type is "Tuple[builtins.int, builtins.str, fallback=__main__.C]"
C.x  # E: Access to generic instance variables via class is ambiguous
[builtins fixtures/classmethod.pyi]

[case testAccessingTypingSelfUnion]
from typing import Self, Union

class C:
    x: Self
class D:
    x: int
x: Union[C, D]
reveal_type(x.x)  # N: Revealed type is "Union[__main__.C, builtins.int]"

[case testCallableProtocolTypingSelf]
from typing import Protocol, Self

class MyProtocol(Protocol):
    __name__: str

    def __call__(
        self: Self,
    ) -> None: ...

def test() -> None: ...
value: MyProtocol = test

[case testCallableProtocolOldSelf]
from typing import Protocol, TypeVar

Self = TypeVar("Self", bound="MyProtocol")

class MyProtocol(Protocol):
    __name__: str

    def __call__(
        self: Self,
    ) -> None: ...

def test() -> None: ...
value: MyProtocol = test

[case testSelfTypeUnionIter]
from typing import Self, Iterator, Generic, TypeVar, Union

T = TypeVar("T")

class range(Generic[T]):
    def __iter__(self) -> Self: ...
    def __next__(self) -> T: ...

class count:
    def __iter__(self) -> Iterator[int]: ...

def foo(x: Union[range[int], count]) -> None:
    for item in x:
        reveal_type(item)  # N: Revealed type is "builtins.int"

[case testGenericDescriptorWithSelfTypeAnnotationsAndOverloads]
from __future__ import annotations
from typing import Any, overload, Callable, TypeVar, Generic, ParamSpec
from typing_extensions import Concatenate

C = TypeVar("C", bound=Callable[..., Any])
S = TypeVar("S")
P = ParamSpec("P")
R = TypeVar("R")

class Descriptor(Generic[C]):
    def __init__(self, impl: C) -> None: ...

    @overload
    def __get__(
        self: Descriptor[C], instance: None, owner: type | None
    ) -> Descriptor[C]: ...

    @overload
    def __get__(
        self: Descriptor[Callable[Concatenate[S, P], R]], instance: S, owner: type | None,
    ) -> Callable[P, R]: ...

    def __get__(self, *args, **kwargs): ...

class Test:
    @Descriptor
    def method(self, foo: int, bar: str) -> bytes: ...

reveal_type(Test().method) # N: Revealed type is "def (foo: builtins.int, bar: builtins.str) -> builtins.bytes"

class Test2:
    @Descriptor
    def method(self, foo: int, *, bar: str) -> bytes: ...

reveal_type(Test2().method) # N: Revealed type is "def (foo: builtins.int, *, bar: builtins.str) -> builtins.bytes"
[builtins fixtures/tuple.pyi]

[case testCallableWithTypeVarInSelfType]
from typing import Generic, TypeVar, Callable

T = TypeVar("T")
V = TypeVar("V")

class X(Generic[T]):
    def f(self: X[Callable[[V], None]]) -> Callable[[V], V]:
        def inner_f(v: V) -> V:
            return v

        return inner_f

reveal_type(X[Callable[[T], None]]().f())  # N: Revealed type is "def [V] (V`4) -> V`4"

[case testSelfInMultipleInheritance]
from typing_extensions import Self

class A:
    foo: int
    def method(self: Self, other: Self) -> None:
        self.foo
        other.foo

class B:
    bar: str
    def method(self: Self, other: Self) -> None:
        self.bar
        other.bar

class C(A, B):  # OK: both methods take Self
    pass
[builtins fixtures/tuple.pyi]