anchor.diff:  %%@private
   match(Temp, Node) -> 
       generalised_unification:expr_match(Temp, Node).
  -            
  +          
       
   try_expr_match([], _Node) ->false;
   try_expr_match([{BeforeExpr, AfterExpr, Cond}|T], Node) 
  
positive.code: is_tree(Node) ->
      refac_syntax:is_tree(Node) orelse refac_syntax:is_wrapper(Node).
  
  
  
  
negative.code:                                 [] -> {refac_syntax:list(Expr), true};
                                  [E] ->
                                      %% No longer can guarantee the correctness of annotations.
                                      {reset_pos_and_range(E), true};
                                  _ ->
                                      E1=refac_syntax:add_ann(
                                           {fake_block_expr, true},
                                           %%refac_syntax:block_expr(Expr)),
                                           reset_pos_and_range(
                                             refac_syntax:block_expr(Expr))),
                                      {E1, true}
                              end;
                          false ->
                              E1=reset_pos_and_range(Expr),
                              {E1,  true}
                      end;
                  _ -> {Node, false}
  