1 files changed, 12 insertions, 0 deletions
diff --git a/testsuite/tests/gadt/T1999.hs b/testsuite/tests/gadt/T1999.hs
new file mode 100644
index 0000000000..70f8531d17
--- /dev/null
+++ b/testsuite/tests/gadt/T1999.hs
@@ -0,0 +1,12 @@
+{-# LANGUAGE FlexibleContexts, FlexibleInstances, GADTs #-}
+
+module Bug where
+
+class C a where
+  f :: G a -> ()
+
+instance (C ()) => C (b c) where
+  f (G x) = f x where
+
+data G a where
+  G  :: G () -> G (b c)