type
  TBaseTest = class
  public type
    PVector = ^TVector;
    TVector = record
      A,B,R: Integer;
    end;
  public
    procedure Execute(var Vector: TVector); virtual; abstract;
  end;

  TTestA = class(TBaseTest)
  public
// E2003 Undeclared identifier: 'TVector'
    procedure Execute(var Vector: TVector); override;
// workaround:
//  procedure Execute(var Vector: TBaseTest.TVector); override;
  end;