Try to rewrite bind to then

[treeowl]

Add RULES to (effectively) rewrite xs >>= const ys to xs *> ys

[foxik]

I think we should add {-# INLINE (>>=) #-} (and maybe also for other methods, see for example the GHC's Monad (ST s) instance http://hackage.haskell.org/package/base-4.7.0.1/docs/src/GHC-ST.html) to the instance, so that bindSeq gets to the call site and make rule firing more likely.

BTW, the foldl' is the default definition of Foldable class, which usually has excessive memory complexity, so this is another place where the >>= could be make more effective.

[treeowl]

This may not be worth the fuss. Documentation should cover it.