testsuite/tests/gadt/data2.hs


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{-# LANGUAGE GADTs, ExistentialQuantification #-}

-- Trac #289

module ShouldCompile where

class Foo a where
  foo :: a -> Int

data T = forall a. T (G a)
data G a where
  A :: G a
  B :: Foo a => a -> G a

doFoo :: T -> Int
doFoo (T A) = 2
doFoo (T (B x)) = foo x