1 files changed, 22 insertions, 0 deletions
diff --git a/testsuite/tests/deriving/should_compile/T14933.hs b/testsuite/tests/deriving/should_compile/T14933.hs
new file mode 100644
index 0000000000..2682d6242f
--- /dev/null
+++ b/testsuite/tests/deriving/should_compile/T14933.hs
@@ -0,0 +1,22 @@
+{-# LANGUAGE DefaultSignatures #-}
+{-# LANGUAGE DeriveAnyClass    #-}
+{-# LANGUAGE TypeFamilies      #-}
+module T14933 where
+
+class Wrapped s where
+  type Unwrapped s :: *
+
+class Fork m where
+    fork :: (x, m)
+
+    default fork :: ( Wrapped m
+                    , Unwrapped m ~ t
+                    , Fork t
+                    ) => (x, m)
+    fork = undefined
+
+newtype MyThing m = MyThing m
+    deriving Fork
+
+instance Wrapped (MyThing m) where
+    type Unwrapped (MyThing m) = m