Singletons/Undef.hs:(0,0)-(0,0): Splicing declarations
    singletons
      [d| foo :: Bool -> Bool
          foo = undefined
          bar :: Bool -> Bool
          bar = error "urk" |]
  ======>
    foo :: Bool -> Bool
    foo = undefined
    bar :: Bool -> Bool
    bar = error "urk"
    type BarSym1 (t :: Bool) = Bar t
    instance SuppressUnusedWarnings BarSym0 where
      suppressUnusedWarnings
        = snd ((GHC.Tuple.(,) BarSym0KindInference) GHC.Tuple.())
    data BarSym0 (l :: TyFun Bool Bool)
      = forall arg. SameKind (Apply BarSym0 arg) (BarSym1 arg) =>
        BarSym0KindInference
    type instance Apply BarSym0 l = Bar l
    type FooSym1 (t :: Bool) = Foo t
    instance SuppressUnusedWarnings FooSym0 where
      suppressUnusedWarnings
        = snd ((GHC.Tuple.(,) FooSym0KindInference) GHC.Tuple.())
    data FooSym0 (l :: TyFun Bool Bool)
      = forall arg. SameKind (Apply FooSym0 arg) (FooSym1 arg) =>
        FooSym0KindInference
    type instance Apply FooSym0 l = Foo l
    type family Bar (a :: Bool) :: Bool where
      Bar a_0123456789876543210 = Apply (Apply ErrorSym0 "urk") a_0123456789876543210
    type family Foo (a :: Bool) :: Bool where
      Foo a_0123456789876543210 = Apply UndefinedSym0 a_0123456789876543210
    sBar ::
      forall (t :: Bool). Sing t -> Sing (Apply BarSym0 t :: Bool)
    sFoo ::
      forall (t :: Bool). Sing t -> Sing (Apply FooSym0 t :: Bool)
    sBar (sA_0123456789876543210 :: Sing a_0123456789876543210)
      = (sError (sing :: Sing "urk")) sA_0123456789876543210
    sFoo (sA_0123456789876543210 :: Sing a_0123456789876543210)
      = sUndefined sA_0123456789876543210