S2259 FP: Null conditional combined with null coalescing

[przemyslaw-piescik]

Description

S2259 is incorrectly reported when using null conditional with null coalescing operator.

Repro steps

        private void Sample()
        {
            string someString = null;

            if (!someString?.Contains("a") ?? true)
                Console.WriteLine("It's null or doesn't contain 'a'");
            else
                Console.WriteLine(someString.Length); //S2259 reported here
        }

Expected behavior

S2259 should not be reported in this case.

Actual behavior

S2259 is reported.

[pavel-mikula-sonarsource]

Hi @przemyslaw-piescik ,

Thank you for reporting this case, I can confirm it as False Positive. We already have similar issue reported in #2528 with the same root cause that you can follow. I'll close this one.

[pavel-mikula-sonarsource]

I'll actually keep this one opened, as it's isolated from the integer constraint issue reported in the other one.