GHC mentions unlifted types out of the blue (to me anyway)

This one does me 'ead in, I accidentally type Ran instead of Swap

{-# Language RankNTypes, DerivingStrategies, TypeApplications, ScopedTypeVariables, GADTs, GeneralizedNewtypeDeriving, InstanceSigs, PolyKinds #-}

import Data.Coerce

newtype Ran g h a = Ran (forall b. (a -> g b) -> h b)

newtype Swap p f g a where
  Swap :: p g f a -> Swap p f g a
  deriving newtype
    Show

class IxPointed m where
  ireturn :: a -> m i i a

instance IxPointed f => IxPointed (Swap f) where
  ireturn :: forall a i. a -> Swap f i i a
  ireturn a = Ran (ireturn a)

and get this error

$ ghci -ignore-dot-ghci /tmp/bug.hs
GHCi, version 8.3.20170605: http://www.haskell.org/ghc/  :? for help
[1 of 1] Compiling Main             ( /tmp/bug.hs, interpreted )

/tmp/bug.hs:17:15: error:
    • Couldn't match expected type ‘Swap f i i a’
                  with actual type ‘Ran g0 h0 a0’
    • In the expression: Ran (ireturn a)
      In an equation for ‘ireturn’: ireturn a = Ran (ireturn a)
      In the instance declaration for ‘IxPointed (Swap f)’
    • Relevant bindings include
        a :: a (bound at /tmp/bug.hs:17:11)
        ireturn :: a -> Swap f i i a (bound at /tmp/bug.hs:17:3)
   |
17 |   ireturn a = Ran (ireturn a)
   |               ^^^^^^^^^^^^^^^

/tmp/bug.hs:17:20: error:
    • Couldn't match a lifted type with an unlifted type
      Expected type: (a0 -> g0 b) -> h0 b
        Actual type: (->) (a0 -> g0 b) (a0 -> g0 b) a
    • In the first argument of ‘Ran’, namely ‘(ireturn a)’
      In the expression: Ran (ireturn a)
      In an equation for ‘ireturn’: ireturn a = Ran (ireturn a)
   |
17 |   ireturn a = Ran (ireturn a)
   |                    ^^^^^^^^^
Failed, modules loaded: none.

Is GHC right to bring up unlifted types? I would guess this is due to the newly added levity polymorphism of (->) :: TYPE rep -> TYPE rep' -> Type

Trac metadata

Trac field	Value
Version	8.2.1
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler
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