Another victim of the state hack

[Simon Peyton-Jones]

| This is a real headache. To be frank, controlling lazy evaluation and
| sharing to get the right complexity for your code can be hard enough at
| the best of times, without the compiler sometimes ignoring the sharing
| you try to ask for...

Yes, I agree.  The trade off is that without the hack all programs go a bit slower, and I don't know how to fix that.  I have not measured this effect recently; maybe it's small. Thanks for updating the ticket with more info; v helpful

S