f_0 :: (forall a_1 . GHC.Classes.Eq (T15738.Foo a_1)) =>
       T15738.Foo x_2 -> T15738.Foo x_2 -> GHC.Types.Bool
f_0 = (GHC.Classes.==)
T15738.hs:(10,3)-(13,11): Splicing declarations
    do d <- [d| f :: (forall a. Eq (Foo a)) => Foo x -> Foo x -> Bool
                f = (==) |]
       runIO $ hPutStrLn stderr $ pprint d
       pure d
  ======>
    f :: (forall a. Eq (Foo a)) => Foo x -> Foo x -> Bool
    f = (==)