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{-# OPTIONS_GHC -Wincomplete-patterns -fforce-recomp #-}
{-# LANGUAGE PatternSynonyms #-}
module T18960b where
pattern P :: a -> a
pattern P x = x
{-# COMPLETE P :: () #-}
bar :: ()
bar = case undefined of
P ((), "hello") -> ()
-- prints too many of apparently the same missing patterns,
-- because we prefer to report positive info (@((), [])@) rather than
-- negative info (@P ((), x:_) where x is not one of {'h'}@)
baz :: ()
baz = case undefined of
P ((), "hello") -> ()
-- This function is proof that we in theory can provide a "better" warning.
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