Examples of errors detected by the V3121 diagnostic

V3121. An enumeration was declared with 'Flags' attribute, but does not set any initializers to override default values.

Azure SDK for .NET

V3121 An enumeration 'BlocksUsing' was declared with 'Flags' attribute, but does not set any initializers to override default values. Fx.cs 69

static class Fx
{
  ....
  public static class Tag
  {
    ....
    [Flags]
    public enum BlocksUsing
    {
      MonitorEnter,
      MonitorWait,
      ManualResetEvent,
      AutoResetEvent,
      AsyncResult,
      IAsyncResult,
      PInvoke,
      InputQueue,
      ThreadNeutralSemaphore,
      PrivatePrimitive,
      OtherInternalPrimitive,
      OtherFrameworkPrimitive,
      OtherInterop,
      Other,

      NonBlocking,
    }
    ....
  }
  ....
}

PowerShell

V3121 An enumeration 'PipelineResultTypes' was declared with 'Flags' attribute, but does not set any initializers to override default values. Command.cs 779

[Flags]
public enum PipelineResultTypes
{
  None,
  Output,
  Error,
  Warning,
  Verbose,
  Debug,
  Information,
  All,
  Null
}