Examples of errors detected by the V3220 diagnostic

V3220. The result of the LINQ method with deferred execution is never used. The method will not be executed.

S&Box

V3220 The result of the 'Where' LINQ method with deferred execution is never used. The method will not be executed. MountHost.cs 114

internal void UnregisterTypes( Assembly assembly )
{
  var assetSourceType = typeof( BaseGameMount );
  var types = assembly
                .GetTypes().Where( t =>
                  assetSourceType.IsAssignableFrom( t )
                  && !t.IsAbstract );

  foreach ( var (ident, source) in Sources.ToArray() )
  {
    if ( source.GetType().Assembly != assembly ) continue;
    if ( source.IsMounted ){ PendingMounts.Add( ident ); }

    source.ShutdownInternal();
    Sources.Remove( ident );
  }
}

QuantConnect Lean

V3220 The result of the 'Where' LINQ method with deferred execution is never used. The method will not be executed. AddOptionWithOnMarketOpenOnlyFilterRegressionAlgorithm.cs 58

public override void OnSecuritiesChanged(SecurityChanges changes)
{
  if (changes.AddedSecurities.All(s => s.Type != SecurityType.Option))
  {
    return;
  }

  var changeOptions = changes.AddedSecurities
                             .Concat(changes.RemovedSecurities
                             .Where(s => s.Type == SecurityType.Option);

  if (Time != Time.Date)
  {
    throw new RegressionTestException($"Expected options filter to be run
                                        only at midnight. Actual was {Time}");
  }
}