Record pattern synonym fields have to be manually exported

The following currently fails to compile:

{-# LANGUAGE PatternSynonyms #-}
module A( T( MkT2 ) ) where

data Impl = Impl Int

newtype T = MkT Impl

pattern MkT2 {x} = MkT (Impl x)

{-# LANGUAGE RecordWildCards #-}
module B where

import A

foo :: T -> Int
foo MkT2{x} = x

As far as GHC can see, in module B, MkT2 does not have a field x. The fix is to manually export x from A:

module A (T(MkT2, x)) where

But this is tedious for records with a large amount of fields