GHC 9.8.1 regression: sometimes can't define associated type family instance when reexported

Summary

GHC 9.8.1 seems to have regressed when defining an associated type family instance when importing the class and the associated type family separately from a reexporting module.

Steps to reproduce

Consider the following three modules

{-# LANGUAGE TypeFamilies #-}

module A (Foo (..)) where

class Foo a where
  type Bar a

module AA (module A) where

import A

{-# LANGUAGE TypeFamilies #-}

module B where

import AA (Bar, Foo)

data X

instance Foo X where
  type Bar X = X

Running ghc A.hs AA.hs B.hs fails to compile since GHC 9.8.1, but compiles just fine with earlier GHC versions (at least GHC 9.6, 9.4, 8.10).

src/B.hs:10:8-10: error: [GHC-54721]
    ‘Bar’ is not a (visible) associated type of class ‘Foo’
   |
10 |   type Bar X = X
   |        ^^^

Note that this does not happen when replacing import AA (Bar, Foo) in B with import A (Bar, Foo) or import AA (Foo(..)).

Expected behavior

I think GHC 9.8.1 should be able to compile this without any errors.

Environment

• GHC version used: 9.8.1
• Operating System: NixOS
• System Architecture: x86_64-linux