Mutually recursive modules using a .hs-boot file

Array.hs

module Array where

import qualified Data.IntMap as M
import {-# SOURCE #-} Object
data Array = Array
  { _map    :: M.IntMap Value
  }

a ! i {- | i >= baseLength ai -} = maybe vnil id $ M.lookup i (_map a)

Object.hs

module Object where

import Array

data Value =
    VInt Integer
  | VArray Array
  | VNil | VFalse | VTrue
  | VError String

vnil :: Value
vnil = VNil

Object.hs-boot

module Object where

data Value

vnil :: Value

Thanks Hammer. I blew it. I had added vnil to Object.hs-boot~ by mistake. (Tab completion at its worst) I appreciate your time.