Should exhaustiveness testing be on by default?

[Don Stewart]

> Catch already does assertion checking (1). Its runtime on moderate to
> small programs (HsColour in particular) is far less than the time GHC
> takes to compile them, and I still have no idea what its runtime is on
> enormous programs (2). An analysis can be whole program and can be
> slow, one does not imply the other.

But the primary problem with Catch is that its analysis not well
defined. I have no guarantee regarding the existence or not of false
positives or false negatives, as Catch has no underlying formal logic to
guide such reasoning.

Despite this, it is a useful tool.

-- Don