Test Trac #7020

2 files changed, 18 insertions, 0 deletions

diff --git a/testsuite/tests/polykinds/T7020.hs b/testsuite/tests/polykinds/T7020.hs
new file mode 100644
index 0000000000..b67c1d8e63
--- /dev/null
+++ b/testsuite/tests/polykinds/T7020.hs
@@ -0,0 +1,17 @@
+{-# LANGUAGE KindSignatures, RankNTypes, PolyKinds, GADTs,
+              FlexibleContexts, DataKinds, TypeFamilies #-}
+
+module T7020 where
+
+import GHC.Exts
+
+data family Sing (a :: k)
+
+class SingKind (Any :: k) => SingI (s :: k) where
+   sing :: Sing s
+
+data SingInstance :: k -> * where
+   SingInstance :: SingI a => SingInstance a
+
+class (b ~ Any) => SingKind (b :: k) where
+   singInstance :: forall (a :: k). Sing a -> SingInstance a
diff --git a/testsuite/tests/polykinds/all.T b/testsuite/tests/polykinds/all.T
index 6c8ef17111..079671a139 100644
--- a/testsuite/tests/polykinds/all.T
+++ b/testsuite/tests/polykinds/all.T
@@ -56,3 +56,4 @@ test('T6049', normal, compile,[''])
 test('T6129', normal, compile_fail,[''])
 test('T7053', normal, compile_fail,[''])
 test('T7053a', normal, compile,[''])
+test('T7020', normal, compile,[''])