anchor.diff:  
   /// Test metadata base class.
   [<AbstractClass>]
  -[<StructuredFormatDisplay("{UniqueName}")>]
  +[<StructuredFormatDisplay("{DebugName}")>]
   type TestMetadata =
   
     val _name : string option
  
positive.code:   override this.DisplayName =
      traverseDisplayName this |> this.createUniqueName
  
  /// Non generic view for test result. (fake base type)
  /// Can use active recognizers: ContextResult cr / TestResult tr / EndMarker
  and ResultNode =
  
negative.code: 
    /// Metadata display name.
    abstract DisplayName : string
  
    /// (For use debugger display)
    abstract DebugName : string
    default this.DebugName =
      match this.Name with
      | Some name -> name
      | None -> this.DisplayName
  
    /// For internal use only.
    member internal this.RawSymbolName = this._symbolName
  