Generic type of setter is leaking across instances

[belm0]

Bug description

Despite typing, the value setter below seems to remember the last assigned type, and applies it to an unrelated instance with different generic type.

from typing import TypeVar, Generic

T = TypeVar('T')


class WrappedVal(Generic[T]):
    def __init__(self, value: T):
        self._value = value

    @property
    def value(self) -> T:
        return self._value

    @value.setter
    def value(self, x: T):
        self._value = x


val1 = WrappedVal('hello')
val1.value = 'goodbye'

val2 = WrappedVal(1.)
print(-val2.value)  # bad operand type for unary -: str

Configuration

No response

Command used

pylint generic_setter.py

Pylint output

generic_setter.py:23:6: E1130: bad operand type for unary -: str (invalid-unary-operand-type)

Expected behavior

no error, since unary minus is valid for float

Pylint version

pylint 2.15.9
astroid 2.12.13
Python 3.8.12 (default, Sep 23 2021, 08:42:37)
[Clang 12.0.0 (clang-1200.0.32.29)]

OS / Environment

No response

Additional dependencies

No response

[belm0]

Defining the class without properties has the same problem, so it's not the setter.

from typing import TypeVar, Generic

T = TypeVar('T')

class WrappedVal(Generic[T]):
    def __init__(self, value: T):
        self.value: T = value

val1 = WrappedVal('hello')
val1.value = 'goodbye'

val2 = WrappedVal(1.)
print(-val2.value)  # bad operand type for unary -: str

[mbyrnepr2]

Thanks @belm0. Can simplify the reproducing-code further with:

class WrappedVal:
    def __init__(self, value):
        self.value = value

val1 = WrappedVal('hello')
val1.value = 'goodbye'

val2 = WrappedVal(1.)
print(-val2.value)  # bad operand type for unary -: str

[belm0]

Well, I think that error would be expected if generics aren't used, as the type inference is doing its best.

So if pylint behaves the same regardless of generic typing, it means that generics are ignored.