Bump `base` version to 4.9.0.0 (closes #11026)
[ghc.git] / testsuite / tests / typecheck / should_fail / tcfail188.hs
1 {-# LANGUAGE RankNTypes, KindSignatures #-}
2 {-# OPTIONS_GHC -Werror #-}
3
4 -- Trac #959
5
6 module ShouldFail where
7
8 data D (f :: (* -> *) -> * -> *) (af :: * -> *) (ax :: *) =
9 D (af (f af ax))
10
11 data CList (f :: (* -> *) -> * -> *) (a :: *) =
12 RCons a (CList (D f) a)
13
14 type CycleList a = forall f. CList f a
15
16 chead :: CycleList a -> a
17 chead ys = case ys of (RCons x xs) -> x