diff --git a/src/mcastu.c b/src/mcastu.c
index 605fb1ab5..50aafc7f3 100644
--- a/src/mcastu.c
+++ b/src/mcastu.c
@@ -932,6 +932,7 @@ spell_would_be_useless(struct monst *mtmp, int spellnum)
             return TRUE;
         break;
     default:
+        break;
     }
     return FALSE;
 }