unused-private-type-var (PYI018)

Derived from the flake8-pyi linter.

What it does

Checks for the presence of unused private TypeVar, ParamSpec or TypeVarTuple declarations.

Why is this bad?

A private TypeVar that is defined but not used is likely a mistake. It should either be used, made public, or removed to avoid confusion.

Example

import typing
import typing_extensions

_T = typing.TypeVar("_T")
_Ts = typing_extensions.TypeVarTuple("_Ts")