False positive error "incompatible type" on bound TypeVar

Originally posted on gitter july 29th, where it was suggested I open a bug report

Bug Report
For this code:

from typing import Generic, TypeVar, Union

ListT = TypeVar("ListT", str, float)


class TestListA(Generic[ListT]):
    def __init__(self, device: ListT) -> None:
        self._device: ListT = device


class TestListB(TestListA[ListT]):
    def __init__(self, device: ListT) -> None:
        super().__init__(device)

mypy outputs error:

test.py:13: error: Argument 1 to "__init__" of "TestListA" has incompatible type "str"; expected "ListT"  [arg-type]
test.py:13: error: Argument 1 to "__init__" of "TestListA" has incompatible type "float"; expected "ListT"  [arg-type]

which is false positive.

Please note that when using a TypeVar with bound=Union, then mypy doesn't complain.

ListT = TypeVar("ListT", bound=Union[str, float])

Your Environment

• Mypy version used: mypy 0.971 (compiled: yes)
• Mypy command-line flags:
• Mypy configuration options from mypy.ini (and other config files):
• Python version used: Python 3.9.12
• Operating system and version:

Commencez par reproduire l’exemple TestVar fourni avec mypy 0.971, puis comparez le comportement de son TypeVar contraint avec la variante bound=Union. Localisez le chemin de vérification des types pour TestListB.init et ajoutez une couverture de régression pour les diagnostics de faux positifs. La tâche est terminée lorsque l’exemple contraint passe sans erreur, tandis que les appels incompatibles continuent d’être diagnostiqués.