The stable reexport `std::collections::Bound` is now deprecated.

Another deprecated reexport could be added in `alloc`,
but that crate is unstable.

Update Cargo

This includes https://github.com/rust-lang/cargo/pull/5255 which fixed regression in `cargo rustdoc` command.

If beta branches before this is merged, we'll need to backport as well

This includes rust-lang/cargo#5255 which fixed regression in
`cargo rustdoc` command.

Remove universes from `ty::ParamEnv`

This change was never meant to land. #48407 takes an alternate approach. However, that PR is now blocked on some issues with canonicalization, and rebasing these reverts gets harder each time, so let's just get this bit out of the way now.

r? @nikomatsakis

Check for known but incorrect attributes

fixes #43988

- Change nested_visit_map so it will recursively check functions

- Add visit_stmt and visit_expr for impl Visitor for CheckAttrVisitor and check for incorrect
inline and repr attributes on staements and expressions

- Add regression test for issue #43988

Stabilize underscore lifetimes

r? @nikomatsakis

Rollup of 12 pull requests

- Successful merges: #49243, #49329, #49364, #49400, #49405, #49427, #49428, #49429, #49439, #49442, #49444, #49452
- Failed merges:

Remove hidden `foo` functions from doc examples; use `Termination` trait.

Fixes https://github.com/rust-lang/rust/issues/49233.

Easier to review with the white-space ignoring `?w=1` feature: https://github.com/rust-lang/rust/pull/49357/files?w=1

Clarify "length" wording in `Vec::with_capacity`.

Fixes https://github.com/rust-lang/rust/issues/49448.

Delete leftover librustc_const_eval

Probably accidentally reintroduced in a rebase/merge

fixes #49440

r? @Mark-Simulacrum

Fix text overlap

Fixes #49006.

r? @QuietMisdreavus

Fix trait implementation not collapsing docs

r? @QuietMisdreavus

Fix collapse toggle insertions on impl with docs

Just went through this one randomly... When an impl has docs, the collapse toggle isn't generated. This fixes it.

r? @QuietMisdreavus

Enable target_feature on any LLVM 6+

In `LLVMRustHasFeature()`, rather than using `MCInfo->getFeatureTable()`
that is specific to Rust's LLVM fork, we can use this in LLVM 6:

    /// Check whether the subtarget features are enabled/disabled as per
    /// the provided string, ignoring all other features.
    bool checkFeatures(StringRef FS) const;

Now rustc using external LLVM can also have `target_feature`.

r? @alexcrichton

Correctly handle impl trait in external items in rustdoc

fixes #49373

r? @QuietMisdreavus

Fix search appearance

Fixes #49377.

r? @QuietMisdreavus

And a screenshot:

<img width="1016" alt="screen shot 2018-03-27 at 10 33 01" src="https://user-images.githubusercontent.com/3050060/37956373-7b522852-31ab-11e8-8915-7e20064b5edd.png">

Implement `shrink_to` method on collections

Fixes #49385

[incremental] Don't panic if decoding the cache fails

If the cached data can't be loaded from disk, just issue a warning to
the user so they know why compilation is taking longer than usual but
don't fail the entire compilation since we can recover by ignorning the
on disk cache.

In the same way, if the disk cache can't be deserialized (because it has
been corrupted for some reason), report the issue as a warning and
continue without failing the compilation. `Decodable::decode()` tends to
panic with various errors like "entered unreachable code" or "index out
of range" if the input data is corrupted. Work around this by catching
panics from the `decode()` calls and continuing without the cached data.

Fixes #48847

don't pass -no-pie to gnu ld

fixes #48884

Stabilize method `String::retain`

Closes #43874

Stabilize match_default_bindings

This includes a submodule update to rustfmt
in order to allow a stable feature declaration.

r? @nikomatsakis

cc https://github.com/rust-lang/rust/issues/42640

Many of the tests this PR touches are merely testing the current lack of desired future behavior around https://github.com/rust-lang/rust/issues/44849 and https://github.com/rust-lang/rust/issues/44848 (cc @tschottdorf). I noticed the bullets for those items were checked on the tracking issue-- I've unchecked them, as they don't appear to have been completed and I don't see any comments indicating that we don't want to pursue them further. Still, I think it's fine to stabilize the current behavior, as I think expanding it in the future should be backwards-compatible.

Introduce a TargetTriple enum to support absolute target paths

This PR replaces target triple strings with a `TargetTriple` enum, which represents either a target triple or a path to a JSON target file. The path variant is used if the `--target` argument has a `.json` extension, else the target triple variant is used.

The motivation of this PR is support for absolute target paths to avoid the need for setting the `RUST_TARGET_PATH` environment variable (see rust-lang/cargo#4905 for more information). For places where some kind of triple is needed (e.g. in the sysroot folder), we use the file name (without extension).

For compatibility, we keep the old behavior of searching for a file named `$(target_triple).json` in `RUST_TARGET_PATH` for non-official target triples.

If the cached data can't be loaded from disk, just issue a warning to
the user so they know why compilation is taking longer than usual but
don't fail the entire compilation since we can recover by ignorning the
on disk cache.

In the same way, if the disk cache can't be deserialized (because it has
been corrupted for some reason), report the issue as a warning and
continue without failing the compilation. `Decodable::decode()` tends to
panic with various errors like "entered unreachable code" or "index out
of range" if the input data is corrupted. Work around this by catching
panics from the `decode()` calls when joining the thread and continuing
without the cached data.

Fixes #48847

Fixes https://github.com/rust-lang/rust/issues/49233.

This includes a submodule update to rustfmt
in order to allow a stable feature declaration.

Probably accidentally reintroduced in a rebase/merge

Allow niche-filling dataful variants to be represented as a ScalarPair

r? @EddyB

Rustdoc support for universal_impl_trait

Hides type parameters synthesized by `impl Trait`-in-argument-position, and enables links to trait names.

<img alt="before" src="https://user-images.githubusercontent.com/7091080/37831646-a61413c6-2ee9-11e8-8ec2-a6137956d922.png" width="450"/>
↓
<img alt="after" src="https://user-images.githubusercontent.com/7091080/37831657-b2ff0ae6-2ee9-11e8-8797-fdad904782bf.png" width="450"/>

Fixes #49309

Rollup of 11 pull requests

- Successful merges: #48639, #49223, #49333, #49369, #49381, #49395, #49399, #49401, #49417, #49202, #49426
- Failed merges:

In `LLVMRustHasFeature()`, rather than using `MCInfo->getFeatureTable()`
that is specific to Rust's LLVM fork, we can use this in LLVM 6:

    /// Check whether the subtarget features are enabled/disabled as per
    /// the provided string, ignoring all other features.
    bool checkFeatures(StringRef FS) const;

Now rustc using external LLVM can also have `target_feature`.