{-# LANGUAGE ViewPatterns #-}
{-# LANGUAGE PatternSynonyms #-}
module M where

-- prefixed [] s = Just s

-- prefixed (p:ps) (s:ss) | p == s = prefixed ps ss  -- GHC BREAKS
prefixed (p:ps) (s:ss) = prefixed ps ss  -- GHC IS FINE

-- prefixed _ _ = Nothing

prefixed2 = uncurry prefixed

pattern Secured x <- (prefixed2 -> Just x)

secure (Secured ("https://", x)) = x ++ " is secured"
secure _ = "insecure"