anchor.diff:  pat_bit_size(N, _, _, _, _, _, St) when is_integer(N), N > 0 -> St;
   pat_bit_size(S, _, Bvs, _, Env, L, St) when is_atom(S) ->
       %% Size must be bound here or occur earlier in binary pattern.
  -    case is_element(S, Bvs) or is_vbound(S, Env) of
  +    case is_element(S, Bvs) or lfe_env:is_vbound(S, Env) of
           true -> St;
           false -> add_error(L, {unbound_symb,S}, St)
       end;
  
positive.code:     %% Add the imports.
      Env0 = foldl(fun ({M,Fs}, Env) ->
                           foldl(fun ({{F,A},R}, E) ->
                                         add_ibinding(M, F, A, R, E)
                                 end, Env, Fs)
                   end, lfe_env:new(), St#lint.imps),
      %% Basic predefines
  
negative.code: check_gexpr([Fun|As], Env, L, St0) when is_atom(Fun) ->
      St1 = check_gargs(As, Env, L, St0),
      %% Function must be a legal guard bif AND not a defined function.
      case lfe_env:is_gbound(Fun, safe_length(As), Env) of
          true -> St1;
          false -> illegal_guard_error(L, St1)
      end;
  