ArrApp arrow arg _ HsHigherOrderApp False)
  = hsep [ppr_lexpr arg, arrowtt, ppr_lexpr arrow]

ppr_expr (
ppr_expr (HsArrApp arrow arg _ HsHigherOrderApp False)
  = hsep [ppr_lexpr arg, arrowtt, ppr_lexpr arrow]
ppr_expr (HsArrApp arrow arg _ HsHigherOrderApp False)
  = hsep [ppr_lexpr arg, arrowtt, ppr_lexpr arrow]