Update to reflect module system as-is

[Centril]

Once the module system changes as specified in https://internals.rust-lang.org/t/relative-paths-in-rust-2018/7883 is done, update guide.

[steveklabnik]

My understanding is that they'll be two different options? @aturon can you add any context here?

[Centril]

What I mean is: Whenever one of the options is chosen over the other we should update the guide.

[joshtriplett]

#74

[steveklabnik]

Has an option been chosen?

[Centril]

@steveklabnik nope; we elected, for the time being, to stabilize the intersection of anchored_use_paths and uniform_paths which makes us forward compatible with the latter. Basically, if you write use foo::bar; and there is a local item foo as well as a crate foo, the compiler will emit an error proposing that the user disambiguate with either use ::foo::bar; or use self::foo::bar; depending on the user's intended meaning.

In the future, we will likely settle on one of the variants and then we can update the guide to reflect that.

[steveklabnik]

It appears like this didn't merge yet rust-lang/rust#53130 (comment)

which means it's not in the RC :/

[steveklabnik]

From @eddyb :

you can't have two variants of a system with feature-gates
so "anchored use paths" is the default on Rust 2018, and has been for a while
only uniform paths require a feature gate and will most likely be a thing later on in 2019 or never shrug
I don't even know what we FCP'd
oh we FCP'd the thing that landed like a week ago

[joshtriplett]

There was a proposal to let #![feature(uniform_paths)] work in the beta for testing, and then turn it off before the release, but that seems to have been dropped on the floor somewhere.

[Centril]

@joshtriplett indeed, I think I was a proponent of that somewhere; but idk what came of it.