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class uses both PEP-695 syntax and legacy syntax

crates/ty_python_semantic/resources/lint_docs/invalid-generic-class.md

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What it does

Checks for the creation of invalid generic classes

Why is this bad?

There are several requirements that you must follow when defining a generic class. Many of these result in TypeError being raised at runtime if they are violated.

Examples

toml
[environment]
python-version = "3.12"
python
from typing_extensions import Generic, TypeVar

T = TypeVar("T")
U = TypeVar("U", default=int)


# class uses both PEP-695 syntax and legacy syntax
class C[U](Generic[T]): ...  # error


# type parameter with default comes before type parameter without default
class D(Generic[U, T]): ...  # error

References