This fixes the regression in #6082.

MERGED from commit e4b800af

As well as being more pleasant, this fixes #1841:
    Data.Typeable: Instances of basic types don't provide qualified
    strings to mkTyCon

To do this we need to define (!) prefix, thus
   (!) arr i = ....
rather than infix

rolling back:

Fri Nov 12 21:09:02 GMT Standard Time 2010  Ian Lynagh <igloo@earth.li>
  * Remove bang patterns from Data.Array.Base
  GHC now refuses to accept top-level bang patterns unless BangPAtterns is
  enabled, which we can't use in Data.Array.Base due to the way ! is used
  as an operator.

    M ./Data/Array/Base.hs -15 +21

GHC now refuses to accept top-level bang patterns unless BangPAtterns is
enabled, which we can't use in Data.Array.Base due to the way ! is used
as an operator.

It is now in its own diffarray package

As well as checking that offset we are reading is actually inside the
array, we now also check that it is "in range" as defined by the Ix
instance. This fixes confusing behaviour (#2120) and improves some error
messages (#2669).