Fix S1940: "Inverted boolean checks" should not suggest inversion for Nullable<T>

[sm-g]

RSPEC-1940

Repro steps

void Foo(string pid, int? id) {
  if (pid == null && !(id > 0))
  {
     // should be either pid or id
  }
}

Expected behavior

No trigger of S1940 rule.

Actual behavior

SL suggests to replace it with:

 if (pid == null && (id <= 0))

but id <= 0 is false when id==null

Related information

• SonarC# 1.23.0.1857
• Visual Studio 15.1

[Evangelink]

Hi @sm-g !

Thanks for the feedback. Indeed there is a bug on our side which is related to nullable value (another linked ticket is #152).