anchor.diff:          lfe_internal:is_lfe_bif(F, Ar) orelse
           lfe_internal:is_erl_bif(F, Ar) of
           true -> St;
  -        false -> undefined_func_error(L, {F,Ar}, St)
  +        false -> undefined_function_error(L, {F,Ar}, St)
       end.
   
   %% check_body(Form, Body, Env, Line, State) -> State.
  
positive.code:     check_foreach(fun (A, S) -> check_expr(A, Env, L, S) end,
                    fun (S) -> add_error(L, bad_args, S) end,
                    St, Args).
  
  %% check_args(Args, Env, L, St) ->
  %%     case lfe_lib:is_proper_list(Args) of
  %%         true -> check_exprs(Args, Env, L, St);
  %%         false -> add_error(L, bad_args, St)
  %%     end.
  
  %% check_exprs(Exprs, Env, Line, State) -> State.
  %% Check a list of expressions. We know it's a proper list.
  
negative.code: bad_form_error(L, F, St) ->
      add_error(L, {bad_form,F}, St).
  
  bad_guard_form_error(L, F, St) ->
      add_error(L, {bad_guard_form,F}, St).
  
  -ifdef(HAS_MAPS).
  illegal_mapkey_error(L, K, St) ->
  