anchor.diff:  
   ufun_clause(Cl0, Ks, St0) ->
       {Cl1,Pvs,Used,_,St1} = uclause(Cl0, [], Ks, St0),
  -    A0 = get_ianno(Cl1),
  +    A0 = get_anno(Cl1),
       A = A0#a{us=subtract(intersection(Used, Ks), Pvs),ns=[]},
       {Cl1#iclause{anno=A},St1}.
   
  
positive.code: 	    [Line] ++ St#core.file
      end.
  
  get_ianno(Ce) ->
      case get_anno(Ce) of
  	#a{}=A -> A;
  	A when is_list(A) -> #a{anno=A}
      end.
  
  get_lineno_anno(Ce) ->
      case get_anno(Ce) of
  	#a{anno=A} -> A;
  
negative.code: 
  uclause(Cl0, Ks, St0) ->
      {Cl1,_Pvs,Used,New,St1} = uclause(Cl0, Ks, Ks, St0),
      A0 = get_anno(Cl1),
      A = A0#a{us=Used,ns=New},
      {Cl1#iclause{anno=A},St1}.
  
  