TH quotes and TypeAbstractions don't work together

See also

• #24757

{-# LANGUAGE TemplateHaskellQuotes #-}
{-# LANGUAGE ImpredicativeTypes #-}
{-# LANGUAGE TypeAbstractions #-}

module TH where

import Language.Haskell.TH

codeId :: Code Q (forall a. a -> a)
codeId = [|| \ @a x -> x :: a ||]

listId :: [forall a. a -> a]
listId = [ \ @a x -> x :: a ]

fails to compile with

TH.hs:10:16: error: [GHC-14964]
    • Invisible type pattern a has no associated forall
    • In the Template Haskell quotation [|| \ @a x -> x :: a ||]
      In the expression: [|| \ @a x -> x :: a ||]
      In an equation for ‘codeId’: codeId = [|| \ @a x -> x :: a ||]
   |
10 | codeId = [|| \ @a x -> x :: a ||]
   |                ^^

Note, the listId is fine, if codeId is commented out, the module compiles fine.

Tested with GHC-9.10 release candidate: The Glorious Glasgow Haskell Compilation System, version 9.10.0.20240426