Minor refactoring

Minor refactoring

Update src/librustc_error_codes/error_codes/E0724.md
Co-authored-by: NDavid Wood <Q0KPU0H1YOEPHRY1R2SN5B5RL@david.davidtw.co>

Update src/librustc_error_codes/error_codes/E0724.md
Co-authored-by: NDavid Wood <Q0KPU0H1YOEPHRY1R2SN5B5RL@david.davidtw.co>

Update src/librustc_error_codes/error_codes/E0724.md
Co-authored-by: NDavid Wood <Q0KPU0H1YOEPHRY1R2SN5B5RL@david.davidtw.co>

Minor refactoring

Revert #71956

...since it caused unsoundness in #73137. Also adds a reduced version of #73137 to the test suite. The addition of the `MaybeInitializedLocals` dataflow analysis has not been reverted, but it is no longer used.

Presumably there is a more targeted fix, but I'm worried that other bugs may be lurking. I'm not yet sure what the root cause of #73137 is.

This will need to get backported to beta.

r? @tmandry

Rollup of 8 pull requests

Successful merges:

 - #71842 (doc: make impl block collapsible if it has an associated constant)
 - #72912 (Add new E0758 error code)
 - #73008 (Update RELEASES.md)
 - #73090 (Use `LocalDefId` directly in `Resolver::export_map`)
 - #73118 (Improve the wording in documentation of std::mem::drop)
 - #73124 (Removed lifetime parameters from Explanation of E0207 )
 - #73138 (Use shorthand linker strip arguments in order to support MacOS)
 - #73143 (Update books)

Failed merges:

r? @ghost

Co-authored-by: NAaron1011 <aa1ronham@gmail.com>

Update books

## nomicon

3 commits in d1517d4e3f29264c5c67bce2658516bb5202c800..bfe1ab96d717d1dda50e499b360f2e2f57e1750a
2020-05-12 13:47:00 -0400 to 2020-06-05 13:19:42 -0400
- Clarify that str data must still be initialized
- Remove language-level UB for non-UTF-8 str
- fix Nomicon transmute UB

## reference

5 commits in becdca9477c9eafa96a4eea5156fe7a2730d9dd2..5d40ba5c2515caffa7790cda621239dc21ef5a72
2020-05-21 21:08:02 +0100 to 2020-06-06 20:25:36 -0700
- Add some links to Disambiguating Function Calls. (rust-lang-nursery/reference#829)
- change bash to sh as shell code blocks language indentifier (rust-lang-nursery/reference#827)
- Fix sentence mistake in array-expr.md (rust-lang-nursery/reference#826)
- removed the word "Second" form the beginning of the 2nd list item and  labelled it as `2` (rust-lang-nursery/reference#822)
- Update fn-like proc-macro invocation restrictions. (rust-lang-nursery/reference#816)

## book

14 commits in e8a4714a9d8a6136a59b8e63544e149683876e36..30cd9dfe71c446de63826bb4472627af45acc9db
2020-05-25 10:29:27 -0500 to 2020-06-07 23:07:19 -0500
- Unnecessarily long type name in Ch 13 (rust-lang/book#2362)
- Tweak example in chapter 10 (rust-lang/book#2363)
- Mention that to_lowercase isn't perfect (rust-lang/book#2364)
- fix typo in CONTRIBUTING.md (rust-lang/book#2360)
- Link German translation in appendix F (rust-lang/book#2347)
- Updates wording on Box example (rust-lang/book#2332)
- fix: match 15-24 with 15-18 (rust-lang/book#2324)
- Reword ch01-03 recap paragraph (rust-lang/book#2305)
- Remove some confusing wording. (rust-lang/book#2358)
- Clarify some wording a bit (rust-lang/book#2357)
- Update ch12-05 PowerShell note (rust-lang/book#2348)
- text -> console (rust-lang/book#2352)
- Improve wording around drop (rust-lang/book#2350)
- Make some statements about crates more correct (rust-lang/book#2349)

## edition-guide

1 commits in 0a8ab5046829733eb03df0738c4fafaa9b36b348..82bec5877c77cfad530ca11095db4456d757f668
2020-05-18 08:34:23 -0500 to 2020-06-03 08:56:02 -0500
- Add stuff for Rust 1.33 (rust-lang/edition-guide#214)

Use shorthand linker strip arguments in order to support MacOS

Per discussion from https://github.com/rust-lang/rust/issues/72110#issuecomment-636609419 onward, the current `-Z strip` options aren't supported by the MacOS linker, but I think only because it doesn't support the longhand arguments `--strip-debug` and `--strip-all`.

This PR switches to using the shorthand arguments `-s` and `-S` instead, which (I believe) are supported by all GCC linkers.

Removed lifetime parameters from Explanation of E0207

Removed lifetime parameters from Explanation of E0207
Fixes #62144

Improve the wording in documentation of std::mem::drop

I thought the original phrasing was somewhat awkward compared to rest of the (very well written) documentation, so figured I would propose a change to improve it.

Use `LocalDefId` directly in `Resolver::export_map`

This is to avoid the final conversion from `NodeId` to `HirId`
during call to `(clone|into)_outputs`

This brings down the post-lowering uses of `NodeId` down to 2 calls to convert the `trait_map`.

cc #50928

r? @petrochenkov

Update RELEASES.md

make catch_unwind line more readable

Add new E0758 error code

doc: make impl block collapsible if it has an associated constant

Fixes #71822.

Enable LVI hardening for x86_64-fortanix-unknown-sgx

This implements mitigations for the Load Value Injection vulnerability (CVE-2020-0551) for the `x86_64-fortanix-unknown-sgx` target by enabling new LLVM passes. More information about LVI and mitigations may be found at https://software.intel.com/security-software-guidance/insights/deep-dive-load-value-injection.

This PR unconditionally enables the mitigations for `x86_64-fortanix-unknown-sgx` since there is no available hardware that doesn't require the mitigations. This may be reconsidered in the future.

* [x] This depends on https://github.com/rust-lang/compiler-builtins/pull/359/

Rollup of 10 pull requests

Successful merges:

 - #72026 (Update annotate-snippets-rs to 0.8.0)
 - #72583 (impl AsRef<[T]> for vec::IntoIter<T>)
 - #72615 (Fix documentation example for gcov profiling)
 - #72761 (Added the documentation for the 'use' keyword)
 - #72799 (Add `-Z span-debug` to allow for easier debugging of proc macros)
 - #72811 (Liballoc impl)
 - #72963 (Cstring `from_raw` and `into_raw` safety precisions)
 - #73001 (Free `default()` forwarding to `Default::default()`)
 - #73075 (Add comments to `Resolve::get_module`)
 - #73092 (Clean up E0646)

Failed merges:

r? @ghost

Clean up E0646

r? @Dylan-DPC

Add comments to `Resolve::get_module`

r? @Manishearth

Free `default()` forwarding to `Default::default()`

It feels a bit redundant to have to say `Default::default()` every time I need a new value of a type that has a `Default` instance.
Especially so, compared to Haskell, where the same functionality is called `def`.
Providing a free `default()` function that forwards to `Default::default()` seems to improve the situation.
The trait is still there, so if someone wants to be explicit and to say `Default::default()` - it still works, but if imported as `std::default::default;`, then the free function reduces typing and visual noise.

Cstring `from_raw` and `into_raw` safety precisions

Fixes #48525.
Fixes #68456.

This issue had two points:

- The one about `from_raw` has been addressed (I hope).
- The other one, about `into_raw`, has only been partially fixed.

About `into_raw`: the idea was to:

> steer users away from using the pattern of CString::{into_raw,from_raw} when interfacing with C APIs that may change the effective length of the string by writing interior NULs or erasing the final NUL

I tried making a `Vec<c_char>` like suggested but my current solution feels very unsafe and *hacky* to me (most notably the type cast), I included it here to make it available for discussion:

```rust
fn main() {
    use std::os::raw::c_char;

    let v = String::from("abc")
        .bytes()
        // From u8 to i8,
        // I feel like it will be a problem for values of u8 > 255
        .map(|c| c as c_char)
        .collect::<Vec<_>>();

    dbg!(v);
}
```

Liballoc impl

Mainly code rearrangements

Add `-Z span-debug` to allow for easier debugging of proc macros

Currently, the `Debug` impl for `proc_macro::Span` just prints out
the byte range. This can make debugging proc macros (either as a crate
author or as a compiler developer) very frustrating, since neither the
actual filename nor the `SyntaxContext` is displayed.

This commit adds a perma-unstable flag `-Z span-debug`. When enabled,
the `Debug` impl for `proc_macro::Span` simply forwards directly to
`rustc_span::Span`. Once #72618 is merged, this will start displaying
actual line numbers.

While `Debug` impls are not subject to Rust's normal stability
guarnatees, we probably shouldn't expose any additional information on
stable until `#![feature(proc_macro_span)]` is stabilized. Otherwise,
we would be providing a 'backdoor' way to access information that's
supposed be behind unstable APIs.

Added the documentation for the 'use' keyword

This is a partial fix of #34601.

I heavily inspired myself from the Reference on the `use` keyword.

I checked the links when compiling the documentation, they should be ok.

I also added an example for the wildcard `*` in the case of types, because it's behaviour is not *import everything* like one might think at first.

Fix documentation example for gcov profiling

closes #72546
Improves the documentation for the unstable Rustflag `-Zprofile` by:
- stating that Incremental compilation must be turned off.
- Adding the other `RUSTFLAGS` that should/need to be turned on (taken from [grcov documentation](https://github.com/mozilla/grcov#example-how-to-generate-gcda-files-for-a-rust-project))
- Mentioning `RUSTC_WRAPPER` to prevent everything getting instrumented.

r? @steveklabnik

impl AsRef<[T]> for vec::IntoIter<T>

Adds `impl<T> AsRef<[T]> for vec::IntoIter<T>`. This mirrors the same trait impl for [`slice::Iter`](https://doc.rust-lang.org/nightly/std/slice/struct.Iter.html). Both types already offer `fn as_slice(&self) -> &[T]`, this just adds the trait impl for `vec::IntoIter`.

If/when `fn as_slice(&self) -> &[T]` stabilizes for `vec::Drain` and `slice::IterMut`, they should get `AsRef<[T]>` impls as well. As thus, tangentially related to #58957.

My ultimate goal here: being able to use `for<T, I: Iterator<Item=T> + AsRef<[T]>> I` to refer to `vec::IntoIter`, `vec::Drain`, and eventually `array::IntoIter`, as an approximation of the set of by-value iterators that can be "previewed" as by-ref iterators. (Actually expressing that as a trait requires GAT.)

Update annotate-snippets-rs to 0.8.0

#59346
I made major changes to this library. In the previous version we worked with owned while in the current one with borrowed.

I have adapted it without changing the behavior.
I have modified the coverage since the previous one did not return correctly the index of the character in the line.

save_analysis: fix some ICEs

Fixes #73020
Fixes #73022
Fixes #73041

Order the Rust and C ABIs first to reduce test churn

This is to avoid the final conversion from `NodeId` to `HirId`
during call to `Resolver::(clone|into)_outputs`.

Rollup of 2 pull requests

Successful merges:

 - #72952 (run-make regression test for issue #70924.)
 - #72977 (Fix codegen tests for RISC-V)

Failed merges:

r? @ghost

Fix codegen tests for RISC-V

Some codegen tests didn't seem relevant (e.g. unsupported annotations).

The RISC-V abi tests were broken by LLVM 10, c872dcf9 fixes that (cc: @msizanoen1)

I'm not sure about skipping catch-unwind.rs and included that change here mostly as a request for comment - I can't tell if that's a bug.

run-make regression test for issue #70924.

Sometime after my PR #72767 (to fix issue #70924) landed, I realized that I *could* make a local regression test, thanks to `rustc --print sysroot`: I can make a fresh "copy" (really mostly symlinks) of the sysroot, and then modify it to recreate the terms of this bug.

Rollup of 5 pull requests

Successful merges:

 - #72764 (Be more careful around ty::Error in generators)
 - #72908 (rename FalseEdges -> FalseEdge)
 - #72970 (Properly handle feature-gated lints)
 - #72998 (Mention that some atomic operations may not be available on some platforms)
 - #73063 (Elide type on liballoc vec)

Failed merges:

r? @ghost

Elide type on liballoc vec

Mention that some atomic operations may not be available on some platforms

fixes #54250

This simply adds a line saying the type/function/method may not be available on some platforms, depending on said platform capabilities.

I *think* I got them all.

Properly handle feature-gated lints

Closes #72694

rename FalseEdges -> FalseEdge

There's just a single false edge in this terminator, not multiple of them.

r? @matthewjasper @jonas-schievink