"Overlapping array copy" exception sorting an array of Tuples

[bearophile]

André Stein:

> I'm trying to sort an array of tuples (Tuple!(uint, string) type) but the
> program bails out with the exception "overlapping array copy"

http://d.puremagic.com/issues/show_bug.cgi?id=5716

I think Phobos unittests are seriously lacking.

Bye,
bearophile