B008: What are "immutable type annotations"?

[clo-vis]

function-call-in-default-argument states that "Parameters with immutable type annotations will be ignored by this rule".

How can I add immutable type annotations to a parameter?

In the example below, the warning is triggered for karg (a KeyView) and for iarg (a SupportsInt), but for some reason not for sarg (a Sequence). I'd like to tell ruff that karg and sarg are immutable (ideally, I'd like to tell ruff that KeysView and SupportsInt are in general immutable).

from collections.abc import KeysView, Sequence
from typing import SupportsInt


def my_fun_0() -> Sequence[str]:
    return []

def my_fun_1() -> KeysView[str]:
    return {}.keys()

def my_fun_2() -> SupportsInt:
    return 1

def bar(sarg: Sequence[str] = my_fun_0(), karg: KeysView[str] = my_fun_1(), iarg: SupportsInt = my_fun_2()) -> None:
    print(sarg, karg, iarg)

Warnings:

• Do not perform function call my_fun_1 in argument defaults; instead, perform the call within the function, or read the default from a module-level singleton variable
• Do not perform function call my_fun_2 in argument defaults; instead, perform the call within the function, or read the default from a module-level singleton variable

[MichaReiser]

There's no configuration today to mark a type as immutable. Ruff uses an internal list.

The only configuration option that exists today is to configure functions that are allowed to be called in a default position. https://docs.astral.sh/ruff/settings/#lintflake8-bugbear But that might not be feasible for you, depending on how youw create KeyView