On Thu, Apr 30, 2009 at 12:44:49PM -0700, Jason Dusek wrote: > I gather that "...making it possible to use ST code directly > on IORef's." is what we have today? No, we have stToIO :: ST RealWorld a -> IO a, but STRef and IORef are still incompatible types. (I now think that's a good thing, because STRefs have more equations than IORefs.)