using error x as a placeholder

[Simon Marlow]

[ moved to glasgow-haskell-users@haskell.org ]

> The timing results were:
>=20
> mkArray1: 11.42u 0.79s 0:13.47 90.6%
> mkArray2: 24.55u 2.31s 0:30.12 89.1%
>=20
> Which is actually *slower*.  Any ideas why?  (These were=20
> compiled with ghc
> 5.02.3 -O2 -fvia-c -fall-strict)

What are the results without -fall-strict?  (-fall-strict is an old
experimental flag and almost certainly doesn't do anything reasonable.
We've de-documented it in the HEAD).

Cheers,
	Simon