Rustdoc links to std library types can bypass the facade

[tomjakubowski]

As an example, generate documentation for this:

#![crate_type="lib"]

pub trait Trait { }

impl<T> Trait for Vec<T> { }

On the docs for the Trait trait, there will be an Implementors section like this:

• impl<T> Trait for Vec<T>

Note that the Vec link goes to docs for the collections crate and not to docs for std. Since the 1.0 release will not host documentation for crates behind the facade, this will lead to broken documentation links for third-party crates.

[steveklabnik]

Triage: this is still true today.

[chordowl]

Triage: looks like this is fixed (see e.g. here or here).

[steveklabnik]

@lukaramu in the second link, it still looks like it's linking to libcollections, not to libstd?

[chordowl]

@steveklabnik seems like I was too superficial, my bad...

Upon taking a closer look, there seem to be multiple components:

A lot of trait implementors are duplicate, this seems to be #25061. The initial entries (mostly, see below) link within libstd (which led me to believe that this was fixed); the entries that are generated dynamically (everything after impl PartialEq for SystemTime) bypass the facade, e.g. Box/Arc/Rc to liballoc, DecodeUtf16Error to libstd_unicode, etc.

Then, even the not dynamically generated entry for the implementation by EnumSet links to libcollections, which in some way makes sense as it isn't in std::collections anyway.

[AlexArgoAi]

This is still a problem today.

Documenting this library:

use std::rc::Rc;

pub fn foo() -> Rc<()> {
    Rc::new(())
}

will produce a link to https://doc.rust-lang.org/nightly/alloc/rc/struct.Rc.html rather than https://doc.rust-lang.org/nightly/std/rc/struct.Rc.html.