anchor.diff:                   compile=[],                    %Compile flags
                    attributes=[],                 %Attributes
                    callbacks=[],                  %Callbacks
  -                 defined=[],                    %Defined functions
  +                 defined,			%Defined functions (gb_set)
                    vcount=0,                      %Variable counter
                    func=[],                       %Current function
                    arity=[],                      %Arity for current function
  
positive.code:     {Efs,St2} = expand_pmod(Tfs, St1),
      %% Get the correct list of exported functions.
      Exports = case member(export_all, St2#expand.compile) of
                    true -> St2#expand.defined;
                    false -> St2#expand.exports
                end,
      %% Generate all functions from stored info.
  
negative.code: 		    true ->
  			 Ps0
  		 end,
  	    Def = gb_sets:to_list(St0#expand.defined),
              {Fs1,Xs,Ds} = sys_expand_pmod:forms(Fs0, Ps,
                                                  St0#expand.exports,
  						Def),
  	    St1 = St0#expand{exports=Xs,defined=gb_sets:from_list(Ds)},
  	    {Fs2,St2} = add_instance(Ps, Fs1, St1),
  	    {Fs3,St3} = ensure_new(Base, Ps0, Fs2, St2),
              {Fs3,St3#expand{attributes = [{abstract, 0, [true]}
  