foldl1 looks flat-out wrong

[treeowl]

I'm working on a patch that will replace the folds anyway, but the current code,

  foldl1 f a | sz == 0   = die "foldl1" "empty array"
             | otherwise = go $ sz-1
   where sz = sizeofArray a
         z = indexArray a 0
         go i | i < 1     = f (go $ i-1) (indexArray a i)
              | otherwise = z

doesn't look remotely right. The i < 1 should be i > 0 or (probably better) i /= 0, or the branches should be swapped, or something.

[treeowl]

We should really backport a bug fix as far back as the bug goes and deprecate the relevant point releases. The backported fix can just change (or remove) the foldl1 definition for Array; it shouldn't need any of the other changes in #87.