Bug.hs

{-# language GADTs #-}
{-# language GeneralizedNewtypeDeriving #-}
{-# language QuasiQuotes #-}
{-# language TemplateHaskell #-}
{-# language TypeFamilies #-}

module Bug where

import Settings ( settings )
import Yesod.Persist ( share, mkPersist, persistUpperCase )

share [mkPersist settings] [persistUpperCase|
Foo
  Id Int
|]

hie.yaml

cradle:
  direct:
    arguments:
      - -Wall

Settings.hs

module Settings where

import Database.Persist.TH

settings = sqlSettings

Works.hs

{-# language GADTs #-}
{-# language GeneralizedNewtypeDeriving #-}
{-# language QuasiQuotes #-}
{-# language TemplateHaskell #-}
{-# language TypeFamilies #-}

module Works where

import Database.Persist.TH ( sqlSettings )
import Yesod.Persist ( share, mkPersist, persistUpperCase )

share [mkPersist sqlSettings] [persistUpperCase|
Foo
  Id Int
|]