Proposal: Make StateT in mtl lazy

Ian Lynagh igloo at
Tue Jan 30 11:58:48 EST 2007

Deadline: 28 February 2007.

I propose we make StateT lazy, as I suspect was the intention all along
and as has been discussed (without reaching a conclusion) before.

The patch is simply (in the definition of (>>=)):

hunk ./Control/Monad/State.hs 195
-               (a, s') <- runStateT m s
+               ~(a, s') <- runStateT m s


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