diff --git a/ansi-tests/TODO b/ansi-tests/TODO
index d699943eb5b979cf2d2508dcad3f369162f6106b..b70581a8a6d69f7a718098851e60f08defefb585 100644
--- a/ansi-tests/TODO
+++ b/ansi-tests/TODO
@@ -118,3 +118,6 @@ Got:      0
     the parent type(s).  (This came up in ABCL.)
 
 44. Add tests for SPECIAL declarations in MACROLET (requested by piso on #lisp)
+
+45. Test (WARN (FORMATTER ...)) (and check that FORMATTER functions work with
+  other error signaling functions.)