-- Checks that the correct type is used checking the using clause of 
-- the group when a by clause is present

{-# OPTIONS_GHC -XMonadComprehensions -XTransformListComp #-}
module ShouldFail where
import GHC.List

foo = [ GHC.List.length x
      | x <- [1..10]
      , then group by x using take 2
      ]