Using return value of a function that returns None is not always reported.

[NielsPT]

Bug description

def f1(i: int) -> None:
    print(i)


def f2() -> None:
    r = f1(2)  # assignment-from-no-return
    if not r:
        print("error")
    if not f1(2):  # no error
        print("error")

Configuration

Command used

pylint experiments/type_test.py -E

Pylint output

experiments/type_test.py:6:4: E1111: Assigning result of a function call, where the function has no return (assignment-from-no-return)

Expected behavior

In the code snippet, line 6 will report an error, but line 9 doesn't. I'd expect to see an error on line 9, since the code essentially does the same thing.
Not sure whether this is by design or a bug. If it's by design, feel free to change this issue to a feature request.

Pylint version

pylint 3.3.7
astroid 3.3.10
Python 3.13.5 (main, Jun 11 2025, 15:36:57) [Clang 17.0.0 (clang-1700.0.13.3)]

OS / Environment

MacOS 15.5

Additional dependencies

[Pierre-Sassoulas]

We check this in visit_assign here:

pylint/pylint/checkers/typecheck.py

Line 1216 in fccbf98

self._check_assignment_from_function_call(node)

We could also do this check in a boolean context where the call is used immediately (maybe using another message like condition-evals-to-constant ?).

[Vimal-Shady]

Hi! 👋 I’d love to work on this issue. Could you please assign this to me? Thank you! 😊

[Pierre-Sassoulas]

Sure :) what are your thoughts on the specifications ?

[lfjxj03]

I checked this code with mypy, and it does report an error on line 9. The error message is as follows:
error: "f1" does not return a value (it only ever returns None) [func-returns-value]