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[ghc.git] / testsuite / tests / typecheck / should_fail / tcfail188.hs
1 {-# LANGUAGE RankNTypes, KindSignatures #-}
2 {-# OPTIONS_GHC -Werror #-}
3
4 -- #959
5
6 module ShouldFail where
7
8 import Data.Kind (Type)
9
10 data D (f :: (Type -> Type) -> Type -> Type)
11 (af :: Type -> Type)
12 (ax :: Type) =
13 D (af (f af ax))
14
15 data CList (f :: (Type -> Type) -> Type -> Type) (a :: Type) =
16 RCons a (CList (D f) a)
17
18 type CycleList a = forall f. CList f a
19
20 chead :: CycleList a -> a
21 chead ys = case ys of (RCons x xs) -> x