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{-# OPTIONS -XImpredicativeTypes #-}
module Foo where
data Capture a = Base a
| Capture (Capture (forall x . x -> a))
g :: Capture (forall a . a -> a)
g = Base id -- Fails; need a rigid signature on 'id'
-- Actually, succeeds now, with visible type application
-- Disagree: should not succeed because it instantiates
-- Base with a forall type
-- This function should definitely be rejected, with or without type signature
h1 = Capture g
h2 :: Capture b
h2 = Capture g
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