Fix S5034 FP: incorrect "ValueTask should be consumed correctly" in Task.WhenAll with different methods on same class instance

[Basssiiie]

Description

Rule S5034 reports a false positive when consuming two different ValueTasks from different methods on the same class, within a Task.WhenAll() and with a AsTask().

Repro steps

class ExampleService
{
    public ValueTask DoThing() => ValueTask.CompletedTask;
    public ValueTask DoAnotherThing() => ValueTask.CompletedTask;
}

class Program
{
    public async Task Main()
    {
        var service = new ExampleService();

        await Task.WhenAll(
            service.DoThing().AsTask(), // <- S5034 error here, even though both lines use different methods.
            service.DoAnotherThing().AsTask()
        );
    }
}

Expected behavior

No warnings here.

Actual behavior

SonarQube/SonarCloud reports the aforementioned warning on the first line within the Task.WhenAll(), even though both ValueTask's are different as they are returned from different methods.

Related information

• SonarLint Visual Studio plugin version: 6.12.0.59751
• Visual Studio version: 17.4.4
• dotnet version: 7.0.102
• Operating System: Windows 10

Hope it helps. Let me know if there are any further questions. :)

[gregory-paidis-sonarsource]

Thank you for opening this issue @Basssiiie .

I can confirm that this is indeed a False Positive. I added a reproducer in our testcases and included this issue to our backlog.

Kind Regards, Greg.

[Basssiiie]

Hello @gregory-paidis-sonarsource

Thank you. Do you have an idea of where this is on the backlog? It's about a year and a half later and we still have this false positive occurring in our code base.

Thanks! 🙂

[gregory-paidis-sonarsource]

Hey there again! Unfortunately, I cannot give you an estimate. When we do our next FP/FN hardening sprint, I will try to prioritize this.

[Basssiiie]

@gregory-paidis-sonarsource Thanks! 🙂