Prior to Python 3.12, generic type aliases were defined as follows:
from typing import TypeAlias, TypeVar
_T = TypeVar("_T")
MyAlias: TypeAlias = set[_T]
Python 3.12 introduced the type statement to facilitate the use of such type aliases, allowing for less confusing and more concise
code:
type MyAlias[T] = set[T]
Python is transitioning away from explicit TypeVar declaration from Python 3.12 onward. This means that Type alias expressions are not
allowed to use TypeVar allocated with an explicit constructor call:
from typing import TypeVar
_T = TypeVar("_T")
type MyAlias[A: str] = dict[A, _T] # Type checker error would be raise
It is a good practice to use the new syntax only, as it fulfills all the requirements of the TypeVar declaration in a more concise and
readable way.
Exceptions
This rule will only raise an issue when the Python version of the analyzed project is set to 3.12 or higher.
