librustc: Allow coercions through arrays.
std: make sure HashMap from_iter uses random initialization by default

It turns out that HashMap's from_iter implementation was being
initialized without the sip keys being randomized. This adds
a custom default hasher that should avoid this potential vulnerability.
std: micro optimize Hash{Map,Set}::{new,with_capacity}
Add `impl Show for &Show`

This makes printing a `Show` trait object much easier.
core: Reorganize slice module.

This is just moving things around so they are defined in a logical order.
core: Remove the unnecessary 'traits' module from 'slice'

This is only breaking for code that references the empty `slice::traits`
module.

[breaking-change]
auto merge of #15281 : alexcrichton/rust/show-for-show, r=kballard

This makes printing a `Show` trait object much easier.
Vim syntax file types and traits cleanup
rustdoc: incorporate stability index throughout

This commit hooks rustdoc into the stability index infrastructure in two
ways:

1. It looks up stability levels via the index, rather than by manual
attributes.

2. It adds stability level information throughout rustdoc output, rather
than just at the top header. In particular, a stability color (with
mouseover text) appears next to essentially every item that appears
in rustdoc's HTML output.

Along the way, the stability index code has been lightly refactored.
libstd: set baseline stability levels.

Earlier commits have established a baseline of `experimental` stability
for all crates under the facade (so their contents are considered
experimental within libstd). Since `experimental` is `allow` by
default, we should use the same baseline stability for libstd itself.

This commit adds `experimental` tags to all of the modules defined in
`std`, and `unstable` to `std` itself.
auto merge of #15263 : aturon/rust/rustdoc-stability-index, r=alexcrichton

This commit hooks rustdoc into the stability index infrastructure in two
ways:

1. It looks up stability levels via the index, rather than by manual
attributes.

2. It adds stability level information throughout rustdoc output, rather
than just at the top header. In particular, a stability color (with
mouseover text) appears next to essentially every item that appears
in rustdoc's HTML output.

Along the way, the stability index code has been lightly refactored.
relicense shootout-mandelbrot.rs

Part of #14248

Main authors:
- @Ryman: OK
- @TeXitoi: OK
- @pcwalton: OK

Minor authors:
- @brson: OK
- @alexcrichton: OK
- @kballard: OK

Remark: @tedhorst was a main contributor, but its contribution
disapear with @pcwalton rewrite at af4ea11
auto merge of #15288 : brson/rust/cleanslice, r=alexcrichton

This does two things:

* Reorganizes the declaration order to be more readable, less random.
* Removes the `slice::traits` module, a public module that does nothing but declare impls of `cmp` traits.
auto merge of #15289 : aturon/rust/libstd-stability, r=alexcrichton

Earlier commits have established a baseline of `experimental` stability
for all crates under the facade (so their contents are considered
experimental within libstd). Since `experimental` is `allow` by
default, we should use the same baseline stability for libstd itself.

This commit adds `experimental` tags to all of the modules defined in
`std`, and `unstable` to `std` itself.
std: move the hash docstring over to std::hash.
Add examples for from_utf8_owned, from_char, from_chars, from_byte
auto merge of #15301 : jasonthompson/rust/docs/str2, r=alexcrichton
Re-arrange TOC.

I'm going to move testing to be right AFTER the guessing game. I wanted it
to be borderline TDD, but I think that, since the first example is just one
file, it might be a bit overkill.

I'm doing this in its own commit to hopefully avoid merge conflicts.
Improve rustdocs for Rc, add examples
doc: Clarify that an error is a compiler error

This was asked on HN, and it's easy to clarify.