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{-# LANGUAGE RankNTypes #-}
-- Blew up GHC 5.04, with:
-- Ambiguous type variable(s) `q' in the constraint `Foo q'
-- arising from a function with an overloaded argument type at Foo.hs:7
-- Expected type: Int -> (forall q1. (Foo q1) => q1 -> a) -> a
-- Inferred type: Int -> (q -> a) -> a
-- In the application `GHC.Err.noMethodBindingError "Foo.hs:7|Foo.foo"#'
--
-- Fix is to give wild-card args to the default methods
-- See GHC.Tc.TyCl.Class.mkDefMethRhs
module ShouldCompile where
class Foo a where
op :: Eq c => c -> (forall b. Eq b => b->b) -> a -> a
instance Foo Int
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