S1940: FP with null-conditional operator

[k0balt]

Repro steps

public static bool IsNullOrEmpty<T>(this IList<T> collection)
    => !(collection?.Count > 0);

Expected behavior

Rule S1940 should not triggered

Actual behavior

On example above sonar suggest replace !(collection?.Count > 0) with collection?.Count <= 0, but if collection == null conditions are not equal.
In same time, in this code:

public static bool IsNotPositive(this int? num)
    => !(num > 0);

Sonar doesn't suggest replacement (and that's right behavior).

Related information

• SonarC# Version 4.9.0.4316
• Visual Studio Version 15.9.12

[andrei-epure-sonarsource]

thanks @k0balt for the detailed reproducer. I confirm the behavior in 7.14