Yes, I have reported it while back. I don't know of the progress in fixing this.
Reported what? #15884? [1] You do realize that there is a very simple workaround for that issue, right? Instead of writing this, which is subject to the pattern-guard completeness issues observed in #15753: f :: Maybe a -> Bool f (id->Nothing) = False f (id->(Just _)) = True You can instead write this: f :: Maybe a -> Bool f (id -> x) = case x of Nothing -> False Just _ -> True This will get proper coverage checking, which means that this technique could be used to remove all of the panicking catch-all cases brought about by dL view patterns. Ryan S. ----- [1] https://ghc.haskell.org/trac/ghc/ticket/15884 [2] https://ghc.haskell.org/trac/ghc/ticket/15753