Test Trac #4185

testsuite/tests/indexed-types/should_compile/T4185.hs

+{-# LANGUAGE DeriveFunctor, StandaloneDeriving, FlexibleInstances, TypeFamilies, GeneralizedNewtypeDeriving #-}
+module T4185 where
+
+data family Foo k :: * -> *
+
+------------- Generalised newtype deriving of user class -----------
+class Bar f where
+	bar :: f a -> Int
+        woo :: f a -> f a
+
+instance Bar Maybe where
+	bar Nothing = 0
+	bar Just{} = 1
+        woo x = x
+
+-- Deriving clause
+newtype instance Foo Int a = FooInt (Maybe a) deriving (Bar)
+
+-- Standalone deriving
+newtype instance Foo Char a = FooChar (Maybe a) 
+deriving instance Bar (Foo Char)
+
+{-
+dBarMaybe :: Bar Maybe
+
+newtype FooInt a = FooInt (Maybe a)
+axiom ax7 a : Foo Int a ~ FooInt a   -- Family axiom
+axiom ax7   : FooInt ~ Maybe         -- Newtype axiom
+
+dBarFooInt :: Bar (Foo Int)
+dBarFooInt = dBarMaybe |> Bar ax7
+-}
+
+------------- Deriving on data types for Functor -----------
+
+-- Deriving clause
+data instance Foo Bool a = FB1 a | FB2 a deriving( Functor )
+
+-- Standalone deriving
+data instance Foo Float a = FB3 a
+deriving instance Functor (Foo Float)
+
+
+--instance Functor (Foo Bool) where
+--  fmap f (FB1 x) = FB1 (f x)
+--  fmap f (FB2 y) = FB2 (f y)
\ No newline at end of file

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

@@ -210,4 +210,5 @@ test('T7585', normal, compile, [''])
 test('T7282', normal, compile, [''])
 test('T7804', normal, compile, [''])
 test('T7837', normal, compile, ['-O -ddump-rule-firings'])
+test('T4185', normal, compile, [''])