1 files changed, 25 insertions, 0 deletions
diff --git a/testsuite/tests/indexed-types/should_compile/Simple15.hs b/testsuite/tests/indexed-types/should_compile/Simple15.hs
new file mode 100644
index 0000000000..8a28d27b6f
--- /dev/null
+++ b/testsuite/tests/indexed-types/should_compile/Simple15.hs
@@ -0,0 +1,25 @@
+{-# LANGUAGE TypeFamilies #-}
+
+module Simple15 where
+
+(<$) :: p -> (p -> q) -> q
+x <$ f = f x
+
+type family Def p
+
+def :: Def p -> p
+def = undefined
+
+data EQU a b = EQU
+
+equ_refl :: EQU a a
+equ_refl = EQU
+
+data FOO = FOO
+type instance Def FOO = EQU () ()
+
+foo :: FOO
+foo = equ_refl <$ def
+-- This works:
+-- foo = def $ equ_refl
+