anchor.diff:  	      {output(set__singleton(external)), state__add_esc(ArgFuns, State)}
   	  end;
   	false ->	  
  -	  State1 = case cerl_closurean:is_escape_op(M1, F1, A) of
  +	  State1 = case is_escape_op(M1, F1, A) of
   		     true -> state__add_esc(ArgFuns, State);
   		     false -> State
   		   end,
  
positive.code: primop(Tree, ArgFuns, State) ->
    F = cerl:atom_val(cerl:primop_name(Tree)),
    A = length(cerl:primop_args(Tree)),
    State1 = case cerl_closurean:is_escape_op(F, A) of
  	     true -> state__add_esc(ArgFuns, State);
  	     false -> State
  	   end,
    case cerl_closurean:is_literal_op(F, A) of
      true -> {output(none), State1};
      false -> {ArgFuns, State1}
    end.
  
  %%------------------------------------------------------------
  %% Set
  
negative.code:     true ->
        M1 = cerl:atom_val(M),
        F1 = cerl:atom_val(F),
        Literal = is_literal_op(M1, F1, A),
        case erl_bifs:is_pure(M1, F1, A) of
  	true ->
  	  case Literal of
  