S3900 FP: Re-assignment of parameters is ignored

[saciervo]

Description

Code in question:

public string Foo(string name)
{
    if (name == null)
    {
        name = Guid.NewGuid().ToString("N");
    }

    return string.Join("_", name.Split(Path.GetInvalidFileNameChars()));
}

Sonar C# falsely complains about the parameter name not getting validated.

Repro steps

You can clone this repo to reproduce the error. The project won't compile.

Expected behavior

No complaints, because there is a null-check in place.

Actual behavior

Code is marked as non-compliant

Known workarounds

None, besides suppression

Related information

• SonarC# Version: 7.16.0.8981
• Visual Studio Version: 2019 (16.2.0)

[andrei-epure-sonarsource]

thanks @saciervo I confirm the FP

[Eli-Black-Work]

We're seeing this as well.