Fixes #43923.

Exclude `impl Trait` functions from everybody_loops.

Fixes #43869.

cc #34511.

Remove useless help part

Part of #32658.

I think this error should be splitted into two parts, each more specific (`anonymous function` vs `type method`).

Add help for static method invalid use

Fixes #30391.

Stabilize rvalue promotion to 'static.

Closes #38865.

Documentation PR at rust-lang-nursery/reference#98.

Stop testing `i586-pc-windows-msvc` on AppVeyor.

Fixes #43881. Reduces AppVeyor test time back to ~2 hours on average.

The i586 libstd was never tested before Aug 13th, so this PR brings the situation back to the previous status-quo.

MIR borrow check (under debug flag)

Here is the current state of MIR borrow check.

It consists of (1.) some refactoring, (2.) a dataflow analysis to identify the borrows themselves, and (3.) a mir "transform" that does the borrow check itself based on the aforementioned dataflow results.

(There's also a drive-by fix to dataflow that I can factor into a separate PR if necessary. Interestingly I could not find a way to observe the bug outside of MIR borrowck.)

To be clear, this branch is not ready to be used as the default borrow check. Thus the code is guarded: To get mir-borrowck to run, you need to either supply an attribute `#[rustc_mir_borrowck]` or a debug flag `-Z borrowck-mir`.

Here are the main issues with the current MIR borrowck as it stands in this PR:

 * No Notes emitted yet, just errors. (So the feedback is definitely inferior compared to AST borrowck today)
 * Lvalue rendering differs between Ast and Mir. (Mostly minor, but replacement of field names with indices is very bad; big priority for me to fix ASAP.)
 * Lots of ICEs (presumably because some MIR operations used here have well-formedness assumptions that are violated in borrowck-broken code)
 * Conflates lots of cases that are distinguished by AST-borrowck
 * Conflates "uninitialized" with "moved" (special case of previous bullet, one that I think should be fixed ASAP)

 (I am hoping to fix as many of the above issues as I can in the near term, but I also would like to land this even if they are *not* all fixed, because the rebasing effort is getting to be a real drag.)

Added two fixmes: The `SimplifyBranches` pass cannot stay where it is,
and `BorrowckMir` should be a query, not a pass. But I am going to
leave those changes to a future PR.

Address review comment: `StatementKind::StorageDead` has an effect (running dtors) relevant to borrowck.

Post-rebase: ariel confirmed `SetDiscriminant` should indeed be a mutate.

One can either use `-Z borrowck-mir` or add the `#[rustc_mir_borrowck]` attribute
to opt into MIR based borrow checking.

Note that regardless of whether one opts in or not, AST-based borrow
check will still run as well.  The errors emitted from AST-based
borrow check will include a "(Ast)" suffix in their error message,
while the errors emitted from MIR-based borrow check will include a
"(Mir)" suffix.

post-rebase: removed check for intra-statement mutual conflict;
replaced with assertion checking that at most one borrow is generated
per statement.

post-rebase: removed dead code: `IdxSet::pairs` and supporting stuff.

Refactored `each_bit`, which traverses a `IdxSet`, so that the bulk of
its implementation lives in `rustc_data_structures`.

(This code is more general purpose than just supporting drop flag elaboration.)

post-rebase: addressed review comment: rename `loc_map`/`location_map` and `rgn_map`/`region_map`.

post-rebase: remove now unnecessary `mut` decl.

post-rebase: address comments: bind iterator expr, and alpha-rename `loc`/`location` and `idx`/`index`.

post-rebase: Do not put "(Ast)" suffix in error msg unless passed `-Z borrowck-mir`.
(But unconditionally include "(Mir)" suffix for mir-borrowck errors.)

Add a note to unused variables

Fixes #26720.

rustc: Fix `unknown_lints` next to an unknown lint

The lint refactoring in #43522 didn't account for `#[allow(unknown_lints)]`
happening at the same node as an unknown lint itself, so this commit updates the
handling to ensure that the local set of lint configuration being built is
queried before looking at the chain of lint levels.

Closes #43809

Clarify writable behavior of readonly-named `Permissions` methods.

Opened primarily to fix https://github.com/rust-lang/rust/issues/41984.

use field init shorthand EVERYWHERE

Like #43008 (f6689991), but [(lacking reasons to be more timid)](https://github.com/rust-lang/rust/pull/43008#issuecomment-312463564) _much more aggressive_.

r? @Mark-Simulacrum

Fixes https://github.com/rust-lang/rust/issues/41984.

Fix ICE with elided lifetimes in return type of foreign functions

cc https://github.com/rust-lang/rust/issues/43567

This is for a preliminary crater/cargobomb run.
Lifetime elision in foreign functions now works exactly like in other functions or function-like entities.

If the breakage is significant, I'll have to partially revert https://github.com/rust-lang/rust/pull/43543 (all the stuff that was required for dealing with late bound lifetimes in this position).

r? @EddyB

Like #43008 (f6689991), but _much more aggressive_.

Add Vec::drain_filter

This implements the API proposed in #43244.

So I spent like half a day figuring out how to implement this in some awesome super-optimized unsafe way, which had me very confident this was worth putting into the stdlib.

Then I looked at the impl for `retain`, and was like "oh dang". I compared the two and they basically ended up being the same speed. And the `retain` impl probably translates to DoubleEndedIter a lot more cleanly if we ever want that.

So now I'm not totally confident this needs to go in the stdlib, but I've got two implementations and an amazingly robust test suite, so I figured I might as well toss it over the fence for discussion.

Make backtraces work on Redox, copying Unix implementation

The `backtrace/` directory here is the same as the Unix one, except for adding an implementation of `get_executable_filename`.

Add method `String::retain`

Behaves like `Vec::retain`, accepting a predicate `FnMut(char) -> bool`
and reducing the string to only characters for which the predicate
returns `true`.

Fixes #43881. Reduces AppVeyor test time back to ~2 hours on
average.

The i586 libstd was never tested before Aug 13th, so this PR
brings the situation back to the previous status-quo.

Add Redox Dockerfile and Travis Environment

This adds Redox to the Travis build. This is an example implementation of https://github.com/rust-lang/rust/issues/43206

Ship the rustdoc book

Fixes #42322, as it's the last step.

Blocked on https://github.com/rust-lang/rust/pull/43790, though they will not conflict.

r? @rust-lang/docs

Fixes #43869.

emit StorageLive for box temporaries

We started emitting StorageDead, so we better emit the corrseponding
StorageLive to avoid problems.

cc #43772 solson/miri#303

Behaves like `Vec::retain`, accepting a predicate `FnMut(char) -> bool`
and reducing the string to only characters for which the predicate
returns `true`.