summaryrefslogtreecommitdiff
path: root/testsuite/tests/typecheck/should_fail/tcfail125.hs
blob: e8d006bab74ef8b9cee8de6c83e1f53a4914354b (plain)
1
2
3
4
5
6
7
8
9
10
11
{-# LANGUAGE DatatypeContexts, ExistentialQuantification #-}

-- Tests the "stupid theta" in pattern-matching
-- when there's an existential as well

module ShouldCompile  where

data (Show a) => Obs a = forall b. LiftObs a b

f :: Obs a -> String    -- Needs a (Show a) context
f (LiftObs _ _) = "yes"