RE: :alnum: broken?

[Drew Adams]

> I just made this very mistake while adding a new regexp-error checking
> feature to xr. Needless to say I now am strongly in favour of turning it
> into a hard error.

Why "needless to say", and why wouldn't a
warning have alerted you?

It's not an error.  It's not an invalid
regexp, even though it has unnecessary
duplication and it doesn't do at all
what you were likely expecting.  That
faulty expectation is why a warning is
appropriate.