diff --git a/src/hb-ot-layout.cc b/src/hb-ot-layout.cc
index bc1e498dd..11c2b33b0 100644
--- a/src/hb-ot-layout.cc
+++ b/src/hb-ot-layout.cc
@@ -1982,6 +1982,8 @@ inline void hb_ot_map_t::apply (const Proxy &proxy,
 	  digest = buffer->digest ();
 	}
       }
+      else
+	(void) buffer->message (font, "skipped lookup %d because no glyph matches", lookup_index);
 
       (void) buffer->message (font, "end lookup %d", lookup_index);
     }