check-python38.test

[case testDecoratedClassLine]
def d(c): ...
@d

class C: ...
class C: ...  # E: Name "C" already defined on line 4

[case testDecoratedFunctionLine]
# flags: --disallow-untyped-defs
def d(f): ...  # type: ignore
@d

def f(): ...  # E: Function is missing a return type annotation \
              # N: Use "-> None" if function does not return a value

[case testIgnoreDecoratedFunction1]
# flags: --disallow-untyped-defs --warn-unused-ignores
def d(f): ...  # type: ignore
@d
# type: ignore
def f(): ...  # type: ignore  # E: Unused "type: ignore" comment

[case testIgnoreDecoratedFunction2]
# flags: --disallow-untyped-defs
def d(f): ...  # type: ignore
@d

def f(): ...  # type: ignore

[case testIgnoreScopeIssue1032]
def f(a: int): ...
f(
    1,
    2,
)  # type: ignore

[case testIgnoreScopeNested1]
def g(x: str) -> str: ...
def f(a: int) -> int: ...
f(
    f(
        g(
            "IGNORE"
        )  # type: ignore
    )
)

[case testIgnoreScopeNested2]
[
    "IGNORE"  # type: ignore
    &
    "IGNORE",
]
[builtins fixtures/list.pyi]

[case testIgnoreScopeNested3]
{
    "IGNORE"
    |  # type: ignore
    "IGNORE",
}
[builtins fixtures/set.pyi]

[case testIgnoreScopeNested4]
{
    None: "IGNORE"
    ^
    "IGNORE",  # type: ignore
}
[builtins fixtures/dict.pyi]

[case testIgnoreScopeNestedNonOverlapping]
def f(x: int): ...
def g(x: int): ...
(
    f("ERROR"),  # E: Argument 1 to "f" has incompatible type "str"; expected "int"
    g("IGNORE"),  # type: ignore
    f("ERROR"),  # E: Argument 1 to "f" has incompatible type "str"; expected "int"
)
[builtins fixtures/tuple.pyi]

[case testIgnoreScopeNestedOverlapping]
def f(x: int): ...
def g(x: int): ...
(
    f("ERROR"), g(  # E: Argument 1 to "f" has incompatible type "str"; expected "int"
        "IGNORE"  # type: ignore
    ), f("ERROR"),  # E: Argument 1 to "f" has incompatible type "str"; expected "int"
)
[builtins fixtures/tuple.pyi]

[case testIgnoreScopeUnused1]
# flags: --warn-unused-ignores
(  # type: ignore  # E: Unused "type: ignore" comment
    "IGNORE"  # type: ignore  # E: Unused "type: ignore" comment
    +  # type: ignore  # E: Unused "type: ignore" comment
    0  # type: ignore
)  # type: ignore  # E: Unused "type: ignore" comment
[builtins fixtures/primitives.pyi]

[case testIgnoreScopeUnused2]
# flags: --warn-unused-ignores
(  # type: ignore  # E: Unused "type: ignore" comment
    "IGNORE"
    -  # type: ignore
    0  # type: ignore  # E: Unused "type: ignore" comment
)  # type: ignore  # E: Unused "type: ignore" comment

[case testIgnoreScopeUnused3]
# flags: --warn-unused-ignores
(  # type: ignore  # E: Unused "type: ignore" comment
    "IGNORE"
    /
    0  # type: ignore
)  # type: ignore  # E: Unused "type: ignore" comment

[case testPEP570ArgTypesMissing]
# flags: --python-version 3.8 --disallow-untyped-defs
def f(arg, /) -> None: ...  # E: Function is missing a type annotation for one or more arguments

[case testPEP570ArgTypesBadDefault]
# flags: --python-version 3.8
def f(arg: int = "ERROR", /) -> None: ...  # E: Incompatible default for argument "arg" (default has type "str", argument has type "int")

[case testPEP570ArgTypesDefault]
# flags: --python-version 3.8
def f(arg: int = 0, /) -> None:
    reveal_type(arg)  # N: Revealed type is "builtins.int"

[case testPEP570ArgTypesRequired]
# flags: --python-version 3.8
def f(arg: int, /) -> None:
    reveal_type(arg)  # N: Revealed type is "builtins.int"

[case testPEP570Required]
# flags: --python-version 3.8
def f(arg: int, /) -> None: ...  # N: "f" defined here
f(1)
f("ERROR")  # E: Argument 1 to "f" has incompatible type "str"; expected "int"
f(arg=1)  # E: Unexpected keyword argument "arg" for "f"
f(arg="ERROR")  # E: Unexpected keyword argument "arg" for "f"

[case testPEP570Default]
# flags: --python-version 3.8
def f(arg: int = 0, /) -> None: ...  # N: "f" defined here
f()
f(1)
f("ERROR")  # E: Argument 1 to "f" has incompatible type "str"; expected "int"
f(arg=1)  # E: Unexpected keyword argument "arg" for "f"
f(arg="ERROR")  # E: Unexpected keyword argument "arg" for "f"

[case testPEP570Calls]
# flags: --python-version 3.8 --no-strict-optional
from typing import Any, Dict
def f(p, /, p_or_kw, *, kw) -> None: ...  # N: "f" defined here
d = None # type: Dict[Any, Any]
f(0, 0, 0)  # E: Too many positional arguments for "f"
f(0, 0, kw=0)
f(0, p_or_kw=0, kw=0)
f(p=0, p_or_kw=0, kw=0)  # E: Unexpected keyword argument "p" for "f"
f(0, **d)
f(**d)  # E: Missing positional argument "p_or_kw" in call to "f"
[builtins fixtures/dict.pyi]

[case testPEP570Signatures1]
# flags: --python-version 3.8
def f(p1: bytes, p2: float, /, p_or_kw: int, *, kw: str) -> None:
    reveal_type(p1)  # N: Revealed type is "builtins.bytes"
    reveal_type(p2)  # N: Revealed type is "builtins.float"
    reveal_type(p_or_kw)  # N: Revealed type is "builtins.int"
    reveal_type(kw)  # N: Revealed type is "builtins.str"

[case testPEP570Signatures2]
# flags: --python-version 3.8
def f(p1: bytes, p2: float = 0.0, /, p_or_kw: int = 0, *, kw: str) -> None:
    reveal_type(p1)  # N: Revealed type is "builtins.bytes"
    reveal_type(p2)  # N: Revealed type is "builtins.float"
    reveal_type(p_or_kw)  # N: Revealed type is "builtins.int"
    reveal_type(kw)  # N: Revealed type is "builtins.str"

[case testPEP570Signatures3]
# flags: --python-version 3.8
def f(p1: bytes, p2: float = 0.0, /, *, kw: int) -> None:
    reveal_type(p1)  # N: Revealed type is "builtins.bytes"
    reveal_type(p2)  # N: Revealed type is "builtins.float"
    reveal_type(kw)  # N: Revealed type is "builtins.int"

[case testPEP570Signatures4]
# flags: --python-version 3.8
def f(p1: bytes, p2: int = 0, /) -> None:
    reveal_type(p1)  # N: Revealed type is "builtins.bytes"
    reveal_type(p2)  # N: Revealed type is "builtins.int"

[case testPEP570Signatures5]
# flags: --python-version 3.8
def f(p1: bytes, p2: float, /, p_or_kw: int) -> None:
    reveal_type(p1)  # N: Revealed type is "builtins.bytes"
    reveal_type(p2)  # N: Revealed type is "builtins.float"
    reveal_type(p_or_kw)  # N: Revealed type is "builtins.int"

[case testPEP570Signatures6]
# flags: --python-version 3.8
def f(p1: bytes, p2: float, /) -> None:
    reveal_type(p1)  # N: Revealed type is "builtins.bytes"
    reveal_type(p2)  # N: Revealed type is "builtins.float"

[case testPEP570Unannotated]
# flags: --python-version 3.8
def f(arg, /): ...  # N: "f" defined here
g = lambda arg, /: arg
def h(arg=0, /): ...  # N: "h" defined here
i = lambda arg=0, /: arg

f(1)
g(1)
h()
h(1)
i()
i(1)
f(arg=0)  # E: Unexpected keyword argument "arg" for "f"
g(arg=0)  # E: Unexpected keyword argument "arg"
h(arg=0)  # E: Unexpected keyword argument "arg" for "h"
i(arg=0)  # E: Unexpected keyword argument "arg"

[case testWalrus]
# flags: --python-version 3.8
from typing import NamedTuple, Optional, List
from typing_extensions import Final

if a := 2:
    reveal_type(a)  # N: Revealed type is "builtins.int"

while b := "x":
    reveal_type(b)  # N: Revealed type is "builtins.str"

l = [y2 := 1, y2 + 2, y2 + 3]
reveal_type(y2)  # N: Revealed type is "builtins.int"
reveal_type(l)  # N: Revealed type is "builtins.list[builtins.int]"

filtered_data = [y3 for x in l if (y3 := a) is not None]
reveal_type(filtered_data)  # N: Revealed type is "builtins.list[builtins.int]"
reveal_type(y3)  # N: Revealed type is "builtins.int"

d = {'a': (a2 := 1), 'b': a2 + 1, 'c': a2 + 2}
reveal_type(d)  # N: Revealed type is "builtins.dict[builtins.str, builtins.int]"
reveal_type(a2)  # N: Revealed type is "builtins.int"

d2 = {(prefix := 'key_') + 'a': (start_val := 1), prefix + 'b': start_val + 1, prefix + 'c': start_val + 2}
reveal_type(d2)  # N: Revealed type is "builtins.dict[builtins.str, builtins.int]"
reveal_type(prefix)  # N: Revealed type is "builtins.str"
reveal_type(start_val)  # N: Revealed type is "builtins.int"

filtered_dict = {k: new_v for k, v in [('a', 1), ('b', 2), ('c', 3)] if (new_v := v + 1) == 2}
reveal_type(filtered_dict)  # N: Revealed type is "builtins.dict[builtins.str, builtins.int]"
reveal_type(new_v)  # N: Revealed type is "builtins.int"

def f(x: int = (c := 4)) -> int:
    if a := 2:
        reveal_type(a)  # N: Revealed type is "builtins.int"

    while b := "x":
        reveal_type(b)  # N: Revealed type is "builtins.str"

    x = (y := 1) + (z := 2)
    reveal_type(x)  # N: Revealed type is "builtins.int"
    reveal_type(y)  # N: Revealed type is "builtins.int"
    reveal_type(z)  # N: Revealed type is "builtins.int"

    l = [y2 := 1, y2 + 2, y2 + 3]
    reveal_type(y2)  # N: Revealed type is "builtins.int"
    reveal_type(l)  # N: Revealed type is "builtins.list[builtins.int]"

    filtered_data = [y3 for x in l if (y3 := a) is not None]
    reveal_type(filtered_data)  # N: Revealed type is "builtins.list[builtins.int]"
    reveal_type(y3)  # N: Revealed type is "builtins.int"

    d = {'a': (a2 := 1), 'b': a2 + 1, 'c': a2 + 2}
    reveal_type(d)  # N: Revealed type is "builtins.dict[builtins.str, builtins.int]"
    reveal_type(a2)  # N: Revealed type is "builtins.int"

    d2 = {(prefix := 'key_') + 'a': (start_val := 1), prefix + 'b': start_val + 1, prefix + 'c': start_val + 2}
    reveal_type(d2)  # N: Revealed type is "builtins.dict[builtins.str, builtins.int]"
    reveal_type(prefix)  # N: Revealed type is "builtins.str"
    reveal_type(start_val)  # N: Revealed type is "builtins.int"

    filtered_dict = {k: new_v for k, v in [('a', 1), ('b', 2), ('c', 3)] if (new_v := v + 1) == 2}
    reveal_type(filtered_dict)  # N: Revealed type is "builtins.dict[builtins.str, builtins.int]"
    reveal_type(new_v)  # N: Revealed type is "builtins.int"

    # https://www.python.org/dev/peps/pep-0572/#exceptional-cases
    (y4 := 3)
    reveal_type(y4)  # N: Revealed type is "builtins.int"

    y5 = (y6 := 3)
    reveal_type(y5)  # N: Revealed type is "builtins.int"
    reveal_type(y6)  # N: Revealed type is "builtins.int"

    f(x=(y7 := 3))
    reveal_type(y7)  # N: Revealed type is "builtins.int"

    reveal_type((lambda: (y8 := 3) and y8)())  # N: Revealed type is "builtins.int"
    y8  # E: Name "y8" is not defined

    y7 = 1.0  # E: Incompatible types in assignment (expression has type "float", variable has type "int")
    if y7 := "x":  # E: Incompatible types in assignment (expression has type "str", variable has type "int")
        pass

    # Just make sure we don't crash on this sort of thing.
    if NT := NamedTuple("NT", [("x", int)]):  # E: "int" not callable
        z2: NT  # E: Variable "NT" is not valid as a type \
                # N: See https://mypy.readthedocs.io/en/stable/common_issues.html#variables-vs-type-aliases

    if Alias := int:  # E: Function "Alias" could always be true in boolean context \
                      # E: Function "int" could always be true in boolean context
        z3: Alias  # E: Variable "Alias" is not valid as a type \
                   # N: See https://mypy.readthedocs.io/en/stable/common_issues.html#variables-vs-type-aliases

    if (reveal_type(y9 := 3) and   # N: Revealed type is "Literal[3]?"
            reveal_type(y9)):       # N: Revealed type is "builtins.int"
        reveal_type(y9)            # N: Revealed type is "builtins.int"

    return (y10 := 3) + y10

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

def check_final() -> None:
    x: Final = 3

    if x := 4:  # E: Cannot assign to final name "x"
        pass

def check_binder(x: Optional[int], y: Optional[int], z: Optional[int], a: Optional[int],
                 b: Optional[int]) -> None:
    reveal_type(x)  # N: Revealed type is "Union[builtins.int, None]"

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

    if x or (y := 1):
        reveal_type(y)  # N: Revealed type is "Union[builtins.int, None]"

    if x and (y := 1):
        reveal_type(y)  # N: Revealed type is "builtins.int"

    if (a := 1) and x:
        reveal_type(a)  # N: Revealed type is "builtins.int"

    if (b := 1) or x:
        reveal_type(b)  # N: Revealed type is "builtins.int"

    if z := 1:
        reveal_type(z)  # N: Revealed type is "builtins.int"

def check_partial() -> None:
    x = None
    if bool() and (x := 2):
        pass

    reveal_type(x)  # N: Revealed type is "Union[builtins.int, None]"

def check_narrow(x: Optional[int], s: List[int]) -> None:
    if (y := x):
        reveal_type(y)  # N: Revealed type is "builtins.int"

    if (y := x) is not None:
        reveal_type(y)  # N: Revealed type is "builtins.int"

    if (y := x) == 10:
        reveal_type(y)  # N: Revealed type is "builtins.int"

    if (y := x) in s:
        reveal_type(y)  # N: Revealed type is "builtins.int"

    if isinstance((y := x), int):
        reveal_type(y)  # N: Revealed type is "builtins.int"

class AssignmentExpressionsClass:
    x = (y := 1) + (z := 2)
    reveal_type(z)  # N: Revealed type is "builtins.int"

    l = [x2 := 1, 2, 3]
    reveal_type(x2)  # N: Revealed type is "builtins.int"

    def __init__(self) -> None:
        reveal_type(self.z)  # N: Revealed type is "builtins.int"

        l = [z2 := 1, z2 + 2, z2 + 3]
        reveal_type(z2)  # N: Revealed type is "builtins.int"
        reveal_type(l)  # N: Revealed type is "builtins.list[builtins.int]"

        filtered_data = [z3 for x in l if (z3 := 1) is not None]
        reveal_type(filtered_data)  # N: Revealed type is "builtins.list[builtins.int]"
        reveal_type(z3)  # N: Revealed type is "builtins.int"

# Assignment expressions from inside the class should not escape the class scope.
reveal_type(x2)  # E: Name "x2" is not defined  # N: Revealed type is "Any"
reveal_type(z2)  # E: Name "z2" is not defined  # N: Revealed type is "Any"

[builtins fixtures/isinstancelist.pyi]

[case testWalrusConditionalTypeBinder]
# flags: --python-version 3.8
from typing import Tuple, Union
from typing_extensions import Literal

class Good:
    @property
    def is_good(self) -> Literal[True]: ...

class Bad:
    @property
    def is_good(self) -> Literal[False]: ...

def get_thing() -> Union[Good, Bad]: ...

if (thing := get_thing()).is_good:
    reveal_type(thing)  # N: Revealed type is "__main__.Good"
else:
    reveal_type(thing)  # N: Revealed type is "__main__.Bad"

def get_things() -> Union[Tuple[Good], Tuple[Bad]]: ...

if (things := get_things())[0].is_good:
    reveal_type(things)  # N: Revealed type is "Tuple[__main__.Good]"
else:
    reveal_type(things)  # N: Revealed type is "Tuple[__main__.Bad]"
[builtins fixtures/list.pyi]

[case testWalrusConditionalTypeCheck]
# flags: --python-version 3.8
from typing import Optional

maybe_str: Optional[str]

if (is_str := maybe_str is not None):
    reveal_type(is_str)  # N: Revealed type is "Literal[True]"
    reveal_type(maybe_str)  # N: Revealed type is "builtins.str"
else:
    reveal_type(is_str)  # N: Revealed type is "Literal[False]"
    reveal_type(maybe_str)  # N: Revealed type is "None"

reveal_type(maybe_str)  # N: Revealed type is "Union[builtins.str, None]"
[builtins fixtures/bool.pyi]

[case testWalrusConditionalTypeCheck2]
# flags: --python-version 3.8
from typing import Optional

maybe_str: Optional[str]

if (x := maybe_str) is not None:
    reveal_type(x)  # N: Revealed type is "builtins.str"
    reveal_type(maybe_str)  # N: Revealed type is "Union[builtins.str, None]"
else:
    reveal_type(x)  # N: Revealed type is "None"
    reveal_type(maybe_str)  # N: Revealed type is "Union[builtins.str, None]"

reveal_type(maybe_str)  # N: Revealed type is "Union[builtins.str, None]"
[builtins fixtures/bool.pyi]

[case testWalrusPartialTypes]
# flags: --python-version 3.8
from typing import List

def check_partial_list() -> None:
    if (x := []):  # E: Need type annotation for "x" (hint: "x: List[<type>] = ...")
        pass

    y: List[str]
    if (y := []):
        pass

    if (z := []):
        z.append(3)
    reveal_type(z)  # N: Revealed type is "builtins.list[builtins.int]"
[builtins fixtures/list.pyi]

[case testWalrusAssignmentAndConditionScopeForLiteral]
# flags: --warn-unreachable --python-version 3.8

if (x := 0):
    reveal_type(x)  # E: Statement is unreachable
else:
    reveal_type(x)  # N: Revealed type is "builtins.int"

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

[case testWalrusAssignmentAndConditionScopeForProperty]
# flags: --warn-unreachable --python-version 3.8

from typing_extensions import Literal

class PropertyWrapper:
    @property
    def f(self) -> str: ...
    @property
    def always_false(self) -> Literal[False]: ...

wrapper = PropertyWrapper()

if x := wrapper.f:
    reveal_type(x)  # N: Revealed type is "builtins.str"
else:
    reveal_type(x)  # N: Revealed type is "builtins.str"

reveal_type(x)  # N: Revealed type is "builtins.str"

if y := wrapper.always_false:
    reveal_type(y)  # E: Statement is unreachable
else:
    reveal_type(y)  # N: Revealed type is "Literal[False]"

reveal_type(y)  # N: Revealed type is "Literal[False]"
[builtins fixtures/property.pyi]

[case testWalrusAssignmentAndConditionScopeForFunction]
# flags: --warn-unreachable --python-version 3.8

from typing_extensions import Literal

def f() -> str: ...

if x := f():
    reveal_type(x)  # N: Revealed type is "builtins.str"
else:
    reveal_type(x)  # N: Revealed type is "builtins.str"

reveal_type(x)  # N: Revealed type is "builtins.str"

def always_false() -> Literal[False]: ...

if y := always_false():
    reveal_type(y)  # E: Statement is unreachable
else:
    reveal_type(y)  # N: Revealed type is "Literal[False]"

reveal_type(y)  # N: Revealed type is "Literal[False]"

def always_false_with_parameter(x: int) -> Literal[False]: ...

if z := always_false_with_parameter(5):
    reveal_type(z)  # E: Statement is unreachable
else:
    reveal_type(z)  # N: Revealed type is "Literal[False]"

reveal_type(z)  # N: Revealed type is "Literal[False]"
[builtins fixtures/tuple.pyi]

[case testWalrusExpr]
# flags: --python-version 3.8
def func() -> None:
    foo = Foo()
    if x := foo.x:
        pass

class Foo:
    def __init__(self) -> None:
        self.x = 123

[case testWalrusTypeGuard]
# flags: --python-version 3.8
from typing_extensions import TypeGuard
def is_float(a: object) -> TypeGuard[float]: pass
def main(a: object) -> None:
    if is_float(x := a):
        reveal_type(x)  # N: Revealed type is "builtins.float"
        reveal_type(a)  # N: Revealed type is "builtins.object"
[builtins fixtures/tuple.pyi]

[case testWalrusRedefined]
# flags: --python-version 3.8
def foo() -> None:
    x = 0
    [x := x + y for y in [1, 2, 3]]
[builtins fixtures/dict.pyi]

[case testWalrusUsedBeforeDef]
# flags: --python-version 3.8
class C:
    def f(self, c: 'C') -> None: pass

(x := C()).f(y)  # E: Cannot determine type of "y"  # E: Name "y" is used before definition
(y := C()).f(y)

[case testOverloadWithPositionalOnlySelf]
# flags: --python-version 3.8
from typing import overload, Optional

class Foo:
    @overload
    def f(self, a: str, /) -> None: ...

    @overload
    def f(self, *, b: bool = False) -> None: ...

    def f(self, a: Optional[str] = None, /, *, b: bool = False) -> None:  # E: Overloaded function implementation does not accept all possible arguments of signature 2
        ...

class Bar:
    @overload
    def f(self, a: str, /) -> None: ...

    @overload  # Notice `/` in sig below:
    def f(self, /, *, b: bool = False) -> None: ...

    def f(self, a: Optional[str] = None, /, *, b: bool = False) -> None:
        ...
[builtins fixtures/bool.pyi]

[case testOverloadPositionalOnlyErrorMessage]
# flags: --python-version 3.8
from typing import overload

@overload
def foo(a: int, /): ...
@overload
def foo(a: str): ...
def foo(a): ...

foo(a=1)
[out]
main:10: error: No overload variant of "foo" matches argument type "int"
main:10: note: Possible overload variants:
main:10: note:     def foo(int, /) -> Any
main:10: note:     def foo(a: str) -> Any

[case testOverloadPositionalOnlyErrorMessageAllTypes]
# flags: --python-version 3.8
from typing import overload

@overload
def foo(a: int, /, b: int, *, c: int): ...
@overload
def foo(a: str, b: int, *, c: int): ...
def foo(a, b, *, c): ...

foo(a=1)
[out]
main:10: error: No overload variant of "foo" matches argument type "int"
main:10: note: Possible overload variants:
main:10: note:     def foo(int, /, b: int, *, c: int) -> Any
main:10: note:     def foo(a: str, b: int, *, c: int) -> Any

[case testOverloadPositionalOnlyErrorMessageMultiplePosArgs]
# flags: --python-version 3.8
from typing import overload

@overload
def foo(a: int, b: int, c: int, /, d: str): ...
@overload
def foo(a: str, b: int, c: int, d: str): ...
def foo(a, b, c, d): ...

foo(a=1)
[out]
main:10: error: No overload variant of "foo" matches argument type "int"
main:10: note: Possible overload variants:
main:10: note:     def foo(int, int, int, /, d: str) -> Any
main:10: note:     def foo(a: str, b: int, c: int, d: str) -> Any

[case testOverloadPositionalOnlyErrorMessageMethod]
# flags: --python-version 3.8
from typing import overload

class Some:
    @overload
    def foo(self, __a: int): ...
    @overload
    def foo(self, a: float, /): ...
    @overload
    def foo(self, a: str): ...
    def foo(self, a): ...

Some().foo(a=1)
[out]
main:13: error: No overload variant of "foo" of "Some" matches argument type "int"
main:13: note: Possible overload variants:
main:13: note:     def foo(self, int, /) -> Any
main:13: note:     def foo(self, float, /) -> Any
main:13: note:     def foo(self, a: str) -> Any

[case testOverloadPositionalOnlyErrorMessageClassMethod]
# flags: --python-version 3.8
from typing import overload

class Some:
    @overload
    @classmethod
    def foo(cls, __a: int): ...
    @overload
    @classmethod
    def foo(cls, a: float, /): ...
    @overload
    @classmethod
    def foo(cls, a: str): ...
    @classmethod
    def foo(cls, a): ...

Some.foo(a=1)
[builtins fixtures/classmethod.pyi]
[out]
main:17: error: No overload variant of "foo" of "Some" matches argument type "int"
main:17: note: Possible overload variants:
main:17: note:     def foo(cls, int, /) -> Any
main:17: note:     def foo(cls, float, /) -> Any
main:17: note:     def foo(cls, a: str) -> Any

[case testUnpackWithDuplicateNamePositionalOnly]
# flags: --python-version 3.8
from typing_extensions import Unpack, TypedDict

class Person(TypedDict):
    name: str
    age: int
def foo(name: str, /, **kwargs: Unpack[Person]) -> None:  # Allowed
    ...
[builtins fixtures/dict.pyi]

[case testPossiblyUndefinedWithAssignmentExpr]
# flags: --python-version 3.8 --enable-error-code possibly-undefined
def f1() -> None:
    d = {0: 1}
    if int():
        x = 1

    if (x := d[x]) is None:  # E: Name "x" may be undefined
        y = x
    z = x
[builtins fixtures/dict.pyi]

[case testNarrowOnSelfInGeneric]
from typing import Generic, TypeVar, Optional

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

class C(Generic[T]):
    x: Optional[T]
    def meth(self) -> Optional[T]:
        if (y := self.x) is not None:
            reveal_type(y)
        return None
[out]
main:9: note: Revealed type is "builtins.int"
main:9: note: Revealed type is "builtins.str"

[case testTypeGuardWithPositionalOnlyArg]
# flags: --python-version 3.8
from typing_extensions import TypeGuard

def typeguard(x: object, /) -> TypeGuard[int]:
    ...

n: object
if typeguard(n):
    reveal_type(n)
[builtins fixtures/tuple.pyi]
[out]
main:9: note: Revealed type is "builtins.int"

[case testTypeGuardKeywordFollowingWalrus]
# flags: --python-version 3.8
from typing import cast
from typing_extensions import TypeGuard

def typeguard(x: object) -> TypeGuard[int]:
    ...

if typeguard(x=(n := cast(object, "hi"))):
    reveal_type(n)
[builtins fixtures/tuple.pyi]
[out]
main:9: note: Revealed type is "builtins.int"

[case testNoCrashOnAssignmentExprClass]
class C:
    [(j := i) for i in [1, 2, 3]]  # E: Assignment expression within a comprehension cannot be used in a class body
[builtins fixtures/list.pyi]

[case testNarrowedVariableInNestedModifiedInWalrus]
from typing import Optional

def walrus_with_nested_error(x: Optional[str]) -> None:
    if x is None:
        x = "a"
    def nested() -> str:
        return x  # E: Incompatible return value type (got "Optional[str]", expected "str")
    if x := None:
        pass
    nested()

def walrus_with_nested_ok(x: Optional[str]) -> None:
    if x is None:
        x = "a"
    def nested() -> str:
        return x
    if y := x:
        pass
    nested()

[case testIgnoreWholeModule]
# flags: --warn-unused-ignores
# type: ignore
IGNORE # type: ignore

[case testUnusedIgnoreVersionCheck]
# flags: --warn-unused-ignores
import sys

if sys.version_info < (3, 6):
    42  # type: ignore
else:
    42  # type: ignore  # E: Unused "type: ignore" comment
[builtins fixtures/ops.pyi]

[case testDictExpressionErrorLocations]
# flags: --pretty
from typing import Dict

other: Dict[str, str]
dct: Dict[str, int] = {"a": "b", **other}
[builtins fixtures/dict.pyi]
[out]
main:5: error: Dict entry 0 has incompatible type "str": "str"; expected "str": "int"
    dct: Dict[str, int] = {"a": "b", **other}
                           ^~~~~~~~
main:5: error: Unpacked dict entry 1 has incompatible type "Dict[str, str]"; expected "SupportsKeysAndGetItem[str, int]"
    dct: Dict[str, int] = {"a": "b", **other}
                                       ^~~~~

[case testWalrusAssignmentEmptyCollection]
from typing import List

y: List[int]
if (y := []):
    reveal_type(y)  # N: Revealed type is "builtins.list[builtins.int]"
[builtins fixtures/list.pyi]