rand::Rng should be implemented for &Rng

[nsf]

Well, I've read that rust doesn't encourage using traits as interfaces. But to me it sounds like a must. On IRC @cmr also suggested me to open an issue. Here it is.

It seems reasonable to have an implementation of Rng for &Rng. Or be it &mut Rng or whatever is necessary to make it work when you use traits as an interface.

[pzol]

Visiting for triage.
@nsf can you provide an example?

[nsf]

Well, I was experimenting with https://github.com/mozilla/rust/blob/master/src/test/bench/noise.rs at the time and thought about replacing the template function it has: https://github.com/mozilla/rust/blob/master/src/test/bench/noise.rs#L26-L29 with a one based on "interfaces".

Besides that, I don't write rust at the moment, so I have no other examples.

[reem]

Triage:

I think this falls under the general complaint that Box<X> does not always implement X. This should be fixed under DST IIRC, so recommending a close.

[steveklabnik]

Yes, object safety and such means that this should work now.