Index: trunk/data/validator/deprecated.mapcss
===================================================================
--- trunk/data/validator/deprecated.mapcss	(revision 8188)
+++ trunk/data/validator/deprecated.mapcss	(revision 8192)
@@ -442,2 +442,8 @@
   throwWarning: tr("key with uncommon character");
 }
+
+/* see #11330 */
+*[/^.$/],
+*[/^..$/][!to] {
+  throwWarning: tr("uncommon short key");
+}