Fix rewrite of reversePoints

src/Data/Text/Internal/Reverse.hs

@@ -40,14 +40,18 @@ reverse (Text ba off len) = runST $ do
     result <- A.unsafeFreeze dest
     pure $ Text result 0 len
 
-reversePoints :: A.Array -> Int -> A.MArray s -> Int -> ST s ()
+reversePoints
+    :: A.Array -- ^ Input array
+    -> Int -- ^ Input index
+    -> A.MArray s -- ^ Output array
+    -> Int -- ^ Output index
+    -> ST s ()
+reversePoints _ _ _ p_out | p_out < 0 = pure ()
 reversePoints ba p_in dest p_out =
     let pointLength = utf8LengthByLeader (A.unsafeIndex ba p_in)
     in do
         A.copyI pointLength dest (p_out - pointLength + 1) ba p_in
-        if p_out - pointLength >= 0
-            then reversePoints' ba (p_in + pointLength) dest (p_out - pointLength)
-            else pure ()
+        reversePoints ba (p_in + pointLength) dest (p_out - pointLength)
 #else
 reverse (Text (A.ByteArray ba) off len) = runST $ do
     marr@(A.MutableByteArray mba) <- A.new len