Error should occur at the timing when only defining the function which only returns `None`

[hyperkai]

*Memo:

• mypy test.py
• mypy 1.18.2
• Python 3.14.0
• Windows 11

The function which only returns None gets the error if defining and calling the function, and printing the return value as shown below:

def func() -> None:
    return None

print(func())
# Error

error: "func" does not return a value (it only ever returns None)

But, only defining and calling the function doesn't get the error as shown below:

def func() -> None:
    return None

func()
# No error

And, only defining the function doesn't get the error as shown below:

def func() -> None:
    return None
# No error

So, the error should occur at the timing when only defining the function as shown below:

def func() -> None:
    return None
# Error

error: "func" does not return a value (it only ever returns None)

[hauntsaninja]

This is the intended behaviour. If you don't think this warning has value, you can disable it with --disable-error-code func-returns-value. See also #3226