Examples of errors detected by the V3153 diagnostic

V3153. Dereferencing the result of null-conditional access operator can lead to NullReferenceException.

MSBuild

V3153 Enumerating the result of null-conditional access operator can lead to NullReferenceException. Consider inspecting: properties?.Keys. MockEngine.cs 159

public void LogTelemetry(string eventName,
                         IDictionary<string, string> properties)
{
  string message
           = $"Received telemetry event '{eventName}'{Environment.NewLine}";

  foreach (string key in properties?.Keys)
  {
    message += $"  Property '{key}' = '{properties[key]}'{Environment.NewLine}";
  }
  ....
}

Nethermind

V3153 Enumerating the result of null-conditional access operator can lead to NullReferenceException. NLogLogger.cs 50

public NLogLogger(....)
{
  ....

  foreach (FileTarget target in global::NLog.LogManager
                                            .Configuration
                                           ?.AllTargets
                                            .OfType<FileTarget>())
    ....
}

.NET Compiler Platform ("Roslyn")

V3153 Enumerating the result of null-conditional access operator can lead to NullReferenceException. CompletionSource.cs 482

private ImmutableArray<char>
GetExcludedCommitCharacters(ImmutableArray<RoslynCompletionItem> roslynItems)
{
  var hashSet = new HashSet<char>();
  foreach (var roslynItem in roslynItems)
  {
    foreach (var rule in roslynItem.Rules?.FilterCharacterRules)  // <=
    {
      if (rule.Kind == CharacterSetModificationKind.Add)
      {
        foreach (var c in rule.Characters)
        {
          hashSet.Add(c);
        }
      }
    }
  }

  return hashSet.ToImmutableArray();
}

Barotrauma

V3153 Enumerating the result of null-conditional access operator can lead to NullReferenceException. Voting.cs 181

public void ClientRead(IReadMessage inc)
{
  ....
  foreach (GUIComponent item in
           GameMain.NetLobbyScreen?.SubList?.Content?.Children)    // <=
  {
    if (item.UserData != null && item.UserData is SubmarineInfo)
    {
      serversubs.Add(item.UserData as SubmarineInfo);
    }
  }
  ....
}

Orleans

V3153 Enumerating the result of null-conditional access operator can lead to NullReferenceException. Silo.cs 180

public Silo(ILocalSiloDetails siloDetails, IServiceProvider services)
{
  ....
  foreach (ILifecycleParticipant<ISiloLifecycle> participant
             in namedLifecycleParticipantCollection?.GetServices(this.Services)
                                                   ?.Select(....))
  {
    participant?.Participate(this.siloLifecycle);
  }
  ....
}

AvalonStudio

V3153 Enumerating the result of null-conditional access operator can lead to NullReferenceException. BreakPointMargin.cs 46

public override void Render(DrawingContext context)
{
  ....
  foreach (var breakPoint in _manager?.OfType<Breakpoint>().Where(....))
  {
    ....
  }
  ....
}