diff --git a/src/or/circuitbuild.c b/src/or/circuitbuild.c
index 65b89e6ddc..f879f13cab 100644
--- a/src/or/circuitbuild.c
+++ b/src/or/circuitbuild.c
@@ -1817,6 +1817,7 @@ build_state_get_exit_nickname(cpath_build_state_t *state)
  *
  * If it's not usable, set *<b>reason</b> to a static string explaining why.
  */
+/*XXXX021 take a routerstatus, not a routerinfo. */
 static int
 entry_guard_set_status(entry_guard_t *e, routerinfo_t *ri,
                        time_t now, or_options_t *options, const char **reason)