[SonarLint][S2259][C#] False Positive - SonarLint is trying to solve the halting problem

[JJungner (Joachim Jungner)]

Looked around and found these topics about the same rule, but different pieces of code.

False positive in rule: is null on at least one execution path

Sonar Qube Version 7.2.1 this sentence is a valid and suggested, when we use recent versions of C# if ((keys?.Count ?? 0) > 0) { int min = Math.Min(chunkSize, keys.Count // <---------- ... } we check for Nulls on the if using the operator ?. and the ?? together .

Object is null on at least one execution path

Version: 6.7.6.38781, scaner: 7.10 (build 7896) Message: 'ex' is null on at least one execution path. Reproduce: void Foo(Exception ex) { switch (ex) { // Particular case: case ArgumentException e: // --snip-- break; // General case: case Exception e: // --snip-- break; // If exception is null, nothing to do: default: return; } // 'ex' cannot be null, but SonarQ…

As well as this blog post about False Positives, where it is apparent the problem is very well understood.

False positives are our enemies, but may still be your friends

Aggregating here for future reference. Both for test cases if/when the rule is up for adjustment, and for other users to see what has happened before, and the official policy on false positives.