Examples of errors detected by the V3097 diagnostic

V3097. Possible exception: type marked by [Serializable] contains non-serializable members not marked by [NonSerialized].

Accord.Net

V3097 Possible exception: the 'DenavitHartenbergNode' type marked by [Serializable] contains non-serializable members not marked by [NonSerialized]. Accord.Math DenavitHartenbergNode.cs 77

public class DenavitHartenbergNodeCollection :
  Collection<DenavitHartenbergNode>
{ .... }

[Serializable]
public class DenavitHartenbergNode
{
  ....
  public DenavitHartenbergNodeCollection Children
  {
    get;
    private set;
  }
  ....
}

Open XML SDK

V3097 Possible exception: type marked by [Serializable] contains non-serializable members not marked by [NonSerialized]. OpenXmlPackageValidationEventArgs.cs 15

[Serializable]
[Obsolete(ObsoleteAttributeMessages.ObsoleteV1ValidationFunctionality, false)]
[EditorBrowsable(EditorBrowsableState.Never)]
public sealed class OpenXmlPackageValidationEventArgs : EventArgs
{
    private string _message;

    [NonSerialized]
    private readonly object _sender;

    [NonSerialized]
    private OpenXmlPart _subPart;

    [NonSerialized]
    private OpenXmlPart _part;

    ....

    internal DataPartReferenceRelationship
        DataPartReferenceRelationship { get; set; } // <=
}