1 files changed, 16 insertions, 0 deletions
diff --git a/testsuite/tests/polykinds/T18300.hs b/testsuite/tests/polykinds/T18300.hs
new file mode 100644
index 0000000000..e0052dc498
--- /dev/null
+++ b/testsuite/tests/polykinds/T18300.hs
@@ -0,0 +1,16 @@
+{-# LANGUAGE GADTs, PolyKinds, DataKinds, TypeFamilies #-}
+
+module Foo where
+
+import GHC.Exts
+import Data.Kind
+
+type family F a :: RuntimeRep
+type instance F Int = 'LiftedRep
+
+data family T a :: TYPE (F a)
+
+data instance T Int where
+  MkT :: Int -> T Int
+
+-- ASSERT error in HEAD