unit foo;
     
    {$mode objfpc}{$H+}
     
    interface
     
    uses
      Classes, SysUtils;
     
    type
     
      { TFoo }
     
      TFoo = class
      private
        PrivateVar: String;
      end;
     
     
      type
        generic TBar<T>=class
        private
          PrivateVar:T;
      end;
     
      TBarInt = specialize TBar<Integer>;
     
    implementation
     
    end.

    program vis;

     

    {$mode objfpc}

    {$h+}

     

    uses foo;

     

    type

      TBarChar = class (specialize TBar<Char>);

      TFooChild = class(TFoo);

     

    var

      AFoo: TFoo;

      AFooChild: TFooChild;

      ABarChar: TBarChar;

      ABarInt: TBarInt;

     

     

    begin

      ABarChar.PrivateVar := 'A';  //compiles (to my surprise: why?)

      ABarInt.PrivateVar := 1;     //vis.lpr(21,11) Error: identifier idents no member "PrivateVar" (if the above is allowed, why not this?)

      AFooChild.PrivateVar := '';  //vis.lpr(22,13) Error: identifier idents no member "PrivateVar" (as expected)

      AFoo.PrivateVar := '';       //vis.lpr(23,8) Error: identifier idents no member "PrivateVar"  (as expected)

    end.