Singletons/EqInstances.hs:0:0:: Splicing declarations
    singEqInstances [''Foo, ''Empty]
  ======>
    instance SEq Foo where
      (%:==) SFLeaf SFLeaf = STrue
      (%:==) SFLeaf ((:%+:) _ _) = SFalse
      (%:==) ((:%+:) _ _) SFLeaf = SFalse
      (%:==) ((:%+:) a a) ((:%+:) b b) = (%:&&) ((%:==) a b) ((%:==) a b)
    type family Equals_0123456789 (a :: Foo) (b :: Foo) :: Bool where
      Equals_0123456789 FLeaf FLeaf = TrueSym0
      Equals_0123456789 ((:+:) a a) ((:+:) b b) = (:&&) ((:==) a b) ((:==) a b)
      Equals_0123456789 (a :: Foo) (b :: Foo) = FalseSym0
    instance PEq (Proxy :: Proxy Foo) where
      type (:==) (a :: Foo) (b :: Foo) = Equals_0123456789 a b
    instance SEq Empty where
      (%:==) a _
        = case a of {
            _ -> error "Empty case reached -- this should be impossible" }
    type family Equals_0123456789 (a :: Empty)
                                  (b :: Empty) :: Bool where
      Equals_0123456789 (a :: Empty) (b :: Empty) = FalseSym0
    instance PEq (Proxy :: Proxy Empty) where
      type (:==) (a :: Empty) (b :: Empty) = Equals_0123456789 a b