Hugs doesn't follow latest layout specification

[Mark Tullsen]

In the following code snippet:

f (x:xs) = "a"
   where
f [] = "b"

We have

   f [] => "b"                     -- in ghc and nhc98 and /latest/ Report
   f [] => Program error: {f []}   -- in hugs

It appears that Hugs has not been updated to follow the
most current Haskell98 Report which explicates the
layout rules in more detail.  (Which specifies that the above
'where' construct should bind nothing rather than binding
the "f [] = ...".)

- Mark