anchor.diff:  
   check_mod_metas(Ms, L, St) ->
       check_foreach(fun (M, S) -> check_mod_meta(M, L, S) end,
  -                  fun (S) -> bad_mdef_error(L, form, S) end,
  +                  fun (S) -> bad_module_error(L, <<"meta form">>, S) end,
                     St, Ms).
   
   check_mod_meta([doc|Docs], L, St) ->
  
positive.code: 
  -else.
  check_gmap(Ps, _, L, St) ->
      undefined_func_error(L, {map,safe_length(Ps)}, St).
  
  check_gmap_size(Form, _, _, L, St) ->
      undefined_func_error(L, {Form,1}, St).
  
  check_gmap_get(Form, _, _, _, L, St) ->
      undefined_func_error(L, {Form,2}, St).
  
  check_gmap_set(Form, _, Ps, _, L, St) ->
      undefined_func_error(L, {Form,safe_length(Ps)+1}, St).
  
  check_gmap_update(Form, _, Ps, _, L, St) ->
      undefined_func_error(L, {Form,safe_length(Ps)+1}, St).
  -endif.
  
  %% pattern(Pattern, Env, L, State) -> {PatVars,State}.
  
negative.code: 
  -else.
  check_map(Ps, _, L, St) ->
      undefined_function_error(L, {map,safe_length(Ps)}, St).
  
  check_map_size(Form, _, _, L, St) ->
      undefined_function_error(L, {Form,1}, St).
  
  check_map_get(Form, _, _, _, L, St) ->
      undefined_function_error(L, {Form,2}, St).
  
  check_map_set(Form, _, Ps, _, L, St) ->
      undefined_function_error(L, {Form,safe_length(Ps)+1}, St).
  
  check_map_update(Form, _, Ps, _, L, St) ->
      undefined_function_error(L, {Form,safe_length(Ps)+1}, St).
  
  check_map_remove(Form, _, Ks, _, L, St) ->
      undefined_function_error(L, {Form,safe_length(Ks)+1}, St).
  -endif.
  
  %% check_record(Record, Fields, Env, Line, State) -> State.
  