What is nothrow for?

[Walter Bright]

Yigal Chripun wrote:
> Since D is not backed up by a giant like Sun/MS/Google/etc it makes
> sense to delegate these features to the community, since it's obvious
> not high on Walter's todo list and annotations make perfect sense for that.

If attributes had meaning only in a library or for some special tool, 
the compiler cannot extract any useful information from them.