check-typevar-unbound.test

[case testUnboundTypeVar]
from typing import TypeVar

T = TypeVar('T')

def f() -> T: # E: A function returning TypeVar should receive at least one argument containing the same TypeVar
    ...
f()

U = TypeVar('U', bound=int)

def g() -> U: # E: A function returning TypeVar should receive at least one argument containing the same TypeVar \
              # N: Consider using the upper bound "int" instead
    ...

V = TypeVar('V', int, str)

# TODO: this should also give an error
def h() -> V:
    ...

[case testInnerFunctionTypeVar]

from typing import TypeVar

T = TypeVar('T')

def g(a: T) -> T:
    def f() -> T:
        ...
    return f()

[case testUnboundIterableOfTypeVars]
from typing import Iterable, TypeVar

T = TypeVar('T')

def f() -> Iterable[T]:
    ...
f()

[case testBoundTypeVar]
from typing import TypeVar

T = TypeVar('T')

def f(a: T, b: T, c: int) -> T:
    ...

[case testNestedBoundTypeVar]
from typing import Callable, List, Union, Tuple, TypeVar

T = TypeVar('T')

def f(a: Union[int, T], b: str) -> T:
    ...

def g(a: Callable[..., T], b: str) -> T:
    ...

def h(a: List[Union[Callable[..., T]]]) -> T:
    ...

def j(a: List[Union[Callable[..., Tuple[T, T]], int]]) -> T:
    ...
[builtins fixtures/tuple.pyi]

[case testUnboundedTypevarUnpacking]
from typing import TypeVar
T = TypeVar("T")
def f(t: T) -> None:
    a, *b = t  # E: "object" object is not iterable