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{-# LANGUAGE GADTs, ScopedTypeVariables #-}
-- Tests for scoped type variables and GADTs
module GADT where
data C x y where
C :: a -> C a a
data D x y where
D :: C b c -> D a c
------- All these should be ok
-- Rejected!
g1 :: forall x y . C x y -> ()
-- C (..) :: C x y
-- Inside match on C, x=y
g1 (C (p :: y)) = ()
-- OK!
g2 :: forall x y . C x y -> ()
-- C (..) :: C x y
-- Inside match on C, x=y
g2 (C (p :: x)) = ()
-- Rejected!
g3 :: forall x y . D x y -> ()
-- D (..) :: D x y
-- C (..) :: C sk y
-- sk = y
-- p :: sk
g3 (D (C (p :: y))) = ()
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