doc comment typo fix

Rewrite the first sentence in slice::sort

For every method, the first sentence should consisely explain what it does,
not how. This sentence usually starts with a verb.

It's really weird for `sort` to be explained in terms of another function,
namely `sort_by`. There's no need for that because it's obvious how `sort`
sorts elements: there is `T: Ord`.

If `sort_by_key` does not have to explicitly state how it's implemented,
then `sort` doesn't either.

r? @steveklabnik

drop_in_place is stable now, don't #![feature] it in the nomicon and a test.

It was stable since Rust 1.8.

r? @GuillaumeGomez

Avoid ICE when pretty-printing non-local MIR item.

This comes up when using `-Zunstable-options --unpretty=mir`. Previously, rustc would ICE due to an unwrap later in this function (after `as_local_node_id`). Instead, we should just ignore items from other crates when pretty-printing MIR.

This was reported in #rust: [this playground code](https://is.gd/PSMBZS) causes an ICE if you click the MIR button. The problem is the mention of the non-local item `std::usize::MAX`, so you can reduce the test case [a lot](https://is.gd/SaLjaa).

r? @EddyB

std: Stabilize APIs for the 1.16.0 release

This commit applies the stabilization/deprecations of the 1.16.0 release, as
tracked by the rust-lang/rust issue tracker and the final-comment-period tag.

The following APIs were stabilized:

* `VecDeque::truncate`
* `VecDeque::resize`
* `String::insert_str`
* `Duration::checked_{add,sub,div,mul}`
* `str::replacen`
* `SocketAddr::is_ipv{4,6}`
* `IpAddr::is_ipv{4,6}`
* `str::repeat`
* `Vec::dedup_by`
* `Vec::dedup_by_key`
* `Result::unwrap_or_default`
* `<*const T>::wrapping_offset`
* `<*mut T>::wrapping_offset`
* `CommandExt::creation_flags` (on Windows)
* `File::set_permissions`
* `String::split_off`

The following APIs were deprecated

* `EnumSet` - replaced with other ecosystem abstractions, long since unstable

Closes #27788
Closes #35553
Closes #35774
Closes #36436
Closes #36949
Closes #37079
Closes #37087
Closes #37516
Closes #37827
Closes #37916
Closes #37966
Closes #38080

Add note for E0117

Fixes #39249.

I just applied the suggestion of @durka since I don't see anything else to add.

travis: Upload all artifacts in build/dist

Previously we only uploaded tarballs, but this modifies Travis/AppVeyor to
upload everything. We shouldn't have anything else in there to worry about and
otherwise we need to be sure to pick up pkg/msi/exe installers.

Hide uninhabitedness checks behind feature gate

This reverts the fix to match exhaustiveness checking so that it can be discussed. The new code is now hidden behind the `never_type` feature gate.

save-analysis: get tables directly, accomodating them being missing

Fixes an ICE when running with save-analysis after an error

r? @EddyB

rustbuild: Add manifest generation in-tree

This commit adds a new tool, `build-manifest`, which is used to generate a
distribution manifest of all produced artifacts. This tool is intended to
replace the `build-rust-manifest.py` script that's currently located on the
buildmaster. The intention is that we'll have a builder which periodically:

* Downloads all artifacts for a commit
* Runs `./x.py dist hash-and-sign`. This will generate `sha256` and `asc` files
  as well as TOML manifests.
* Upload all generated hashes and manifests to the directory the artifacts came
  from.
* Upload *all* artifacts (tarballs and hashes and manifests) to an archived
  location.
* If necessary, upload all artifacts to the main location.

This script is intended to just be the second step here where orchestrating
uploads and such will all happen externally from the build system itself.

cc #38531

Detect double reference when applying binary op

``` rust
let vr = v.iter().filter(|x| {
    x % 2 == 0
});
```

will now yield the following compiler output:

``` bash
ERROR binary operation `%` cannot be applied to type `&&_`
NOTE this is a reference of a reference to a type that `%` can be applied to,
you need to dereference this variable once for this operation to work
NOTE an implementation of `std::ops::Rem` might be missing for `&&_`
```

The first NOTE is new.

Fix #33877

----

Thanks to @estebank for providing the original PR #34420 (of which this is a tweaked rebase).

rustc: Remove all "consider using an explicit lifetime parameter" suggestions

These give so many incorrect suggestions that having them is
detrimental to the user experience. The compiler should not be
suggesting changes to the code that are wrong - it is infuriating: not
only is the compiler telling you that _you don't understand_ borrowing,
_the compiler itself_ appears to not understand borrowing. It does not
inspire confidence.

r? @nikomatsakis

travis: Turn off core dumps on OSX

I've seen these take up quite a bit of log space and I have the sneaking
suspicion that they're just making our test suite take longer (sometimes timing
out on 32-bit OSX now). In any case the backtraces haven't proven too useful,
unfortunately.

Stabilize Self and associated types in struct expressions and patterns

Rebase of https://github.com/rust-lang/rust/pull/37734
Closes https://github.com/rust-lang/rust/issues/37544
r? @nikomatsakis

Hide a few more standard library symbols

These commits touch up some of the symbol visibility rules for some crates related to the standard library, notably:

* Symbols that are `pub extern` and `#[no_mangle]` which are internal-to-rust ABI things are no longer at the `C` export level, but the `Rust` export level. This includes allocators, panic runtimes, and compiler builtins.
* The libbacktrace library is now compiled with `-fvisibility=hidden` to ensure that we don't export those symbols.

We don't want these symbols exported from the standard library, this is
just an internal implementation detail of the standard library
currently.

Closes #34984

This hides symbols from various unstable and implementation-detail
crates of the standard library. Although typically transitive exported
`pub extern` functions are exported from cdylibs, these crates aren't
necessary as they're all implementation details.

Closes #34493

incr.comp.: Make cross-crate tracking for incr. comp. opt-in.

The current implementation of cross-crate dependency tracking can cause quite long compile times and high memory usage for some crates (see #39208 for example). This PR therefore makes that part of dependency tracking optional. Incremental compilation still works, it will only have very coarse dep-tracking for upstream crates.

r? @nikomatsakis

Point to immutable arg/fields when trying to use as &mut

Present the following output when trying to access an immutable borrow's
field as mutable:

```
error[E0389]: cannot borrow data mutably in a `&` reference
  --> $DIR/issue-38147-1.rs:27:9
   |
26 | fn f(&self) {
   |      -----  use `&mut self` here to make mutable
27 |     f.s.push('x');
   |     ^^^ assignment into an immutable reference
```

And the following when trying to access an immutable struct field as mutable:

```
error: cannot borrow immutable borrowed content `*self.s` as mutable
  --> $DIR/issue-38147-3.rs:17:9
   |
12 |     s: &'a String
   |     ------------- use `&'a mut String` here to make mutable
...|
16 |     fn f(&self) {
   |          -----  use `&mut self` here to make mutable
17 |         self.s.push('x');
   |         ^^^^^^ cannot borrow as mutable
```

Fixes #38147.

Bounds parsing refactoring 2

See https://github.com/rust-lang/rust/pull/37511 for previous discussion.
cc @matklad

Relaxed parsing rules:
 - zero bounds after `:` are allowed in all contexts.
 - zero predicates are allowed after `where`.
- trailing separator `,` is allowed after predicates in `where` clauses not followed by `{`.

Other parsing rules:
 - trailing separator `+` is still allowed in all bound lists.

Code is also cleaned up and tests added.

I haven't touched parsing of trait object types yet, I'll do it later.

These give so many incorrect suggestions that having them is
detrimental to the user experience. The compiler should not be
suggesting changes to the code that are wrong - it is infuriating: not
only is the compiler telling you that _you don't understand_ borrowing,
_the compiler itself_ appears to not understand borrowing. It does not
inspire confidence.

Point to immutable borrow arguments and fields when trying to use them as
mutable borrows. Add label to primary span on "cannot borrow as mutable"
errors.

Present the following output when trying to access an immutable borrow's
field as mutable:

```
error[E0389]: cannot borrow data mutably in a `&` reference
  --> $DIR/issue-38147-1.rs:27:9
   |
26 | fn f(&self) {
   |      -----  use `&mut self` here to make mutable
27 |     f.s.push('x');
   |     ^^^ assignment into an immutable reference
```

And the following when trying to access an immutable struct field as mutable:

```
error: cannot borrow immutable borrowed content `*self.s` as mutable
  --> $DIR/issue-38147-3.rs:17:9
   |
12 |     s: &'a String
   |     ------------- use `&'a mut String` here to make mutable
...|
16 |     fn f(&self) {
   |          -----  use `&mut self` here to make mutable
17 |         self.s.push('x');
   |         ^^^^^^ cannot borrow as mutable
```

This comes up when using `-Zunstable-options --unpretty=mir`.
Previously, rustc would ICE due to an unwrap later in this function
(after `as_local_node_id`). Instead, we should just ignore items from
other crates when pretty-printing MIR.

Fixes an ICE when running with save-analsysis after an error

End temporary lifetimes being extended by `let X: &_` hints

cc #39283

r? @nikomatsakis

I've seen these take up quite a bit of log space and I have the sneaking
suspicion that they're just making our test suite take longer (sometimes timing
out on 32-bit OSX now). In any case the backtraces haven't proven too useful,
unfortunately.

Rename tcx.map to the far more descriptive tcx.hir.

Also a bit more renaming because `ast_map` and `'ast` were still used with HIR.
Main motivation is to "free up" `tcx.map`, or rather, `tcx.maps`, to consolidate `ty::maps` there.

r? @nikomatsakis

Add a distinct error code and description for "main function has wron…

…g type"

For every method, the first sentence should consisely explain what it does,
not how. This sentence usually starts with a verb.

It's really weird for `sort` to be explained in terms of another function,
namely `sort_by`. There's no need for that because it's obvious how `sort`
sorts elements: there is `T: Ord`.

If `sort_by_key` does not have to explicitly state how it's implemented,
then `sort` doesn't either.

Remove Reflect

PR for removing the `Reflect` trait. Opened so that a crater run can be done for testing the impact: https://github.com/rust-lang/rust/issues/27749#issuecomment-272665163

Fixes #27749

It was stable since Rust 1.8.

process trait/impl items directly from the visitor callback

The current setup processes impl/trait items while visiting
the impl/trait. This means we basically have this setup:

    <Lots> -> TypeckItemBody(Impl) -> Tables(ImplItem{0,1,2,3})

But this was largely an artifact of the older code. By moving the
processing of items into method dedicated for their use, we produce this
setup:

    <Little> -> TypeckItemBody(ImplItem0) -> Tables(ImplItem0)
    ...
    <Little> -> TypeckItemBody(ImplItem3) -> Tables(ImplItem3)

r? @michaelwoerister

Also, we might consider removing the `TypeckItemBody` node altogether and just using `Tables` as the task. `Tables` is its primary output, I imagine? That would reduce size of dep-graph somewhat.

cc @EddyB -- perhaps this pattern applies elsewhere?

Fix wording around sort guarantees

Fixes #38524

/cc @rust-lang/libs @stjepang