Cross-posted from StackOverflow: http://stackoverflow.com/questions/44107336/how-to-define-a-type-in-a-templatehaskell-function-and-use-it-in-the-same-functi

Is there any way to have as single TH function, define a type, and use the type, as well? Relevant code below. `PersonPoly2` is being defined by `makeRecordSplice` and then being passed to `makeAdaptorAndInstance` (provided by Opalaye), which is also a TH function.

Relevant code given below:

{-# LANGUAGE FlexibleContexts #-}

{-# LANGUAGE FlexibleInstances #-}

{-# LANGUAGE FunctionalDependencies #-}

{-# LANGUAGE MultiParamTypeClasses #-}

{-# LANGUAGE OverloadedStrings #-}

{-# LANGUAGE TemplateHaskell #-}

module Lib where

import Data.Profunctor.Product.TH (makeAdaptorAndInstance)

import Language.Haskell.TH

makeRecordSplice :: Q [Dec]

makeRecordSplice = [d|

data PersonPoly2 a b = Person2

{ id :: a

, name :: b

}

makeRecordAndAdapter :: Q [Dec]

makeRecordAndAdapter = do

record <- makeRecordSplice

adapter <- makeAdaptorAndInstance "pPerson2" (mkName "PersonPoly2")

return $ record ++ adapter

-------------

/home/Projects/scratch/app/Main.hs:26:1: error:

‘PersonPoly2’ is not in scope at a reify

Failed, modules loaded: Lib.

-- Saurabh.