[jhc] Typechecker hiccup?

[Samuel J.J.Bronson]

I just tried to compile this program (based on figure one in "The GRIN Project:
A Highly Optimising Back End for Lazy Functional Languages"):


{-# OPTIONS_JHC -N -fffi #-}

import Jhc.Basics
import Jhc.Int
import Jhc.Num
import Jhc.Order

default (Integer, Double)

main = sum (upto 1 10)

upto m n | m > n     = []
         | otherwise = m : upto (m+1) n

sum []     = 0
sum (x:xs) = x + sum xs


And I got a stupid error about a missing "put" method for IORef. It seems that
the typechecker isn't getting rid of all the MetaVars in this program...