{-# LANGUAGE ScopedTypeVariables, ExistentialQuantification #-} -- !!! scoped type variables w/ existential types -- this test failed in GHC 5.00 module ShouldCompile where data T = forall a. MkT [a] f :: T -> T f (MkT [t::a]) = MkT t3 where t3::[a] = [t,t,t]