rustdoc still broken

Closes https://github.com/rust-lang/rust/issues/30008

`#[stable]`, `#[unstable]` and `#[rustc_deprecated]` are now guarded by `#[feature(staged_api)]`

r? @brson

Fixes #27092
Fixes #30005

The graph extent mechanism is not good. I have some ideas for a better replacement, but this PR simply removes it. It also stops recursing on statement scopes and processes them using an "on the heap" stack, which fixes #29466.

r? @dotdash

Part of #29428

Part of #29428

`socket_addr` was renamed to `local_addr` in 1.0beta.

See: f798674b

r? @steveklabnik

`socket_addr` was renamed to `local_addr` in 1.0beta.

See: f798674b

This was to support rustpkg but is unused now.

- Successful merges: #30013, #30038, #30040
- Failed merges: #30030

Closes #30031.

At this point of the book, reader have likely use `cargo new --bin`,
likely 2 times, once if they are lazy. This remind them of the `cargo`
syntax.

I was myself unsure whether it was `cargo create`, `cargo new`, and
whether it would initialize in current working directory or needed a
target.

--

Otherwise thanks, I've been writing rust for a few hours, and likes it so far.

Part of https://github.com/rust-lang/rust/issues/29333

Fixes #22425

Also fixes #30007, since it's just a change from `true` to `false`.

See https://github.com/rust-lang/rfcs/pull/1246 for discussion.

are tons of let statements. Fixes #29466.

Typical algebra currently doesn't work on the types in std::time currently (see
[this comment][comment]), so tweak the tests to account for this property.

[comment]: https://github.com/rust-lang/rust/issues/29866#issuecomment-159093809

Closes #29970

the right information, but it's hard to maintain in the face of
optimizations, and in the form that the analyses probably actually want.

Closes #30031.

Closes #25810.
Closes #29276.

r? @alexcrichton

At this point of the book, reader have likely use `cargo new --bin`,
likely 2 times, once if they are lazy. This remind them of the `cargo`
syntax.

I was myself unsure whether it was `cargo create`, `cargo new`, and
whether it would initialize in current working directory or needed a
target.

Trait references are always invariant, so all uses of subtyping between
them are equivalent to using equality.

Moreover, the overlap check was previously performed twice per impl
pair, once in each direction. It is now performed only once, and
internally uses the equality check.

On glium, a crate that spends some time in coherence, this change sped
up coherence checking by a few percent (not very significant).

r? @nikomatsakis

This was to support rustpkg but is unused now.

Part of https://github.com/rust-lang/rust/issues/29333