Test Snoyman's emailed data family deriving program

testsuite/tests/ghc-regress/indexed-types/should_compile/DataFamDeriv.hs

+{-# LANGUAGE TypeFamilies #-}
+module DataFamDeriv where
+
+data family Foo a
+data Bar = Bar
+data instance Foo Bar
+    = Bar1 | Bar2 | Bar3 | Bar4 | Bar5 | Bar6 | Bar7 | Bar8 | Bar9
+    deriving Eq
+
+
+

testsuite/tests/ghc-regress/indexed-types/should_compile/all.T

@@ -159,3 +159,4 @@ test('T4356', normal, compile, [''])
 test('T4484', normal, compile, [''])
 test('T4492', normal, compile, [''])
 test('T4494', normal, compile, [''])
+test('DataFamDeriv', normal, compile, [''])