1 files changed, 1 insertions, 2 deletions
diff --git a/2020/19.hs b/2020/19.hs
index 3ae886f..a3afb8f 100644
--- a/2020/19.hs
+++ b/2020/19.hs
@@ -34,8 +34,7 @@ matches :: Gram -> [Int] -> String -> Bool
 matches _ [] [] = True
 matches gram@(Gram arr) (r:rs) (c:cs) =
     case arr A.! r of
-      S c' | c == c' -> matches gram rs cs
-           | otherwise -> False
+      S c' -> c == c' && matches gram rs cs
       D alts -> any (\alt -> matches gram (alt ++ rs) (c:cs)) alts
 matches _ _ _ = False