Removing MonadFail from Monad

[Tom Ellis]

On Mon, Dec 16, 2013 at 11:26:39PM +0100, David Luposchainsky wrote:
> I feel like there are a couple of elephants in the room that are sort of
> important but nobody really addresses them directly. One of them was
> what became the AMP, and `fail` is another one.

Is it written up somewhere why pattern match failure in 'do' is a 'fail' but
pattern match failure elsewhere is just pattern match failure?

Malcolm Wallace mentioned that it convenient when writing parsers, and his
example is indeed neat, but is has someone done a more substantial
investigation the benefits of this special case?

Tom