base: Add @since on GHC.IO.Handle.Lock.hUnlock
[ghc.git] / testsuite / tests / typecheck / should_compile / tc182.hs
1 {-# LANGUAGE DatatypeContexts, ExistentialQuantification #-}
2
3 -- Tests the "stupid theta" in pattern-matching
4 -- when there's an existential as well
5
6 module ShouldCompile where
7
8 data (Show a) => Obs a = forall b. LiftObs a b
9
10 f :: Show a => Obs a -> String
11 f (LiftObs _ _) = "yes"