A.hs

{-# LANGUAGE ImplicitParams #-}
{-# LANGUAGE TemplateHaskell #-}
module A where

import Language.Haskell.TH
import Data.List (sortBy)


sort   :: (?cmp :: a -> a -> Ordering) => [a] -> [a]
sort    = sortBy ?cmp

me :: Q (TExp ([Int] -> [Int]))
me =
  let ?cmp = compare in [|| sort ||]

B.hs

{-# LANGUAGE ImplicitParams #-}
{-# LANGUAGE TemplateHaskell #-}
module B where

import A

foo :: [Int] -> [Int]
foo =
  --let ?cmp = compare in
  $$(me)