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{-# LANGUAGE MultiParamTypeClasses, FunctionalDependencies,
ExistentialQuantification #-}
-- !!! Functional dependencies and existentials
-- Hugs (February 2000) doesn't like it. It says
-- Variable "e" in constraint is not locally bound
module ShouldCompile where
class Collection c e | c -> e where
empty :: c
put :: c -> e -> c
data SomeCollection e = forall c . Collection c e => MakeSomeCollection c
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