`mir_stats` mod has not been used since c1ff104.

Popping and pushing from the end of a linked list is constant time. This
documentation is already there for popping and pushing from the front.

@bors: r+ 38fe8d2 rollup

Also, provide a suggestion for the correct syntax.

Includes some new stabilized intrinsics for the wasm32 target!

Closes rust-lang#56292

Initially, rust-lang#50233 accidentally changed the capacity of empty ZST. This
was pointed out during code review. This commit adds a test to prevent
capacity of ZST vectors from accidentally changing to prevent that
from happening again.

…previously not in test suite.

This adds a new rustc target-configuration called 'x86_64-unknown_uefi'.
Furthermore, it adds a UEFI base-configuration to be used with other
targets supported by UEFI (e.g., i386, armv7hl, aarch64, itanium, ...).

UEFI systems provide a very basic operating-system environment, meant
to unify how systems are booted. It is tailored for simplicity and fast
setup, as it is only meant to bootstrap other systems. For instance, it
copies most of the ABI from Microsoft Windows, rather than inventing
anything on its own. Furthermore, any complex CPU features are
disabled. Only one CPU is allowed to be up, no interrupts other than
the timer-interrupt are allowed, no process-separation is performed,
page-tables are identity-mapped, ...

Nevertheless, UEFI has an application model. Its main purpose is to
allow operating-system vendors to write small UEFI applications that
load their kernel and terminate the UEFI system. However, many other
UEFI applications have emerged in the past, including network-boot,
debug-consoles, and more.

This UEFI target allows to compile rust code natively as UEFI
applications. No standard library support is added, but libcore can be
used out-of-the-box if a panic-handler is provided. Furthermore,
liballoc works as well, if a `GlobalAlloc` handler is provided. Both
have been tested with this target-configuration.

Note that full libstd support is unlikely to happen. While UEFI does
have standardized interfaces for networking and alike, none of these
are mandatory and they are unlikely to be shipped in common consumer
firmwares. Furthermore, several features like process-separation are
not available (or only in very limited fashion). Those parts of libstd
would have to be masked.

Co-Authored-By: estebank <estebank@users.noreply.github.com>

…KodrAus

Documentation for impl From for AtomicBool and other Atomic types

As part of issue rust-lang#51430 (cc @skade).

The impl is very simple, so not sure if we need to go into any details.

Add lint for items deprecated in future

Resolves rust-lang#55892

…omatsakis

Remove not used mod

`mir_stats` mod has not been used since c1ff104.

Clearer error message for dead assign

I'm not that this is the right place for this (if it needs an RFC or not).

I had the problem where I misunderstood the compiler lint message rust-lang#56436 and other people seem to have had the same problem https://www.reddit.com/r/rust/comments/8cy9p4/value_assigned_to_is_never_read/.

I think this new wording might be slightly clearer (and help out beginners like me). I'm very new though, so there might be some nuance I'm missing that would make this more confusing or a bad idea for other reasons.

I thought I would create a PR to make it easy to change the code if the consensus was that it would make sense to make a change.

If this is the wrong place for this sort of thing I'll happily delete/move it.

…MatthewJasper

polonius tweaks

- bump polonius to 0.6.0
- fix 2-phase-borrow activations

r? @matthewjasper

Document time of back operations of a Linked List

Popping and pushing from the end of a linked list is constant time. This
documentation is already there for popping and pushing from the front.

@bors: r+ 38fe8d2 rollup

#[must_use] on traits in stdlib

Based on rust-lang#55506.

Adds `#[must_use]` attribute to traits in the stdlib:
- `Iterator`
- `Future`
- `FnOnce`
- `Fn`
- `FnMut`

There may be other traits that should have the attribute, but I couldn't find/think of any.

overhaul external doc attribute diagnostics

This PR improves the error handling and spans for the external doc attribute. Many cases that silently failed before now emit errors, spans are tightened, and the errors have help and suggestions.

I tried to address all the cases that users ran into in the tracking issue.

cc rust-lang#44732

r? @QuietMisdreavus

…matsakis

Update the stdsimd submodule

Includes some new stabilized intrinsics for the wasm32 target!

Closes rust-lang#56292

…k, r=jonas-schievink

fix install broken link

solves rust-lang#56690

…alexcrichton

Always set the RDRAND and RDSEED features on SGX

Not sure if this is 100% correct.

This [Intel article](https://software.intel.com/en-us/articles/intel-software-guard-extensions-tutorial-part-5-enclave-development) goes in great depth regarding using (untrusted) CPUID to see whether RDRAND/RDSEED is supported, and explains what happens to the enclave if the CPUID result is faked.

I'd say that an implementation of SGX that doesn't make RDRAND available to the enclave is so severely limited/broken that it's ok if you get #UD in that case. The case is less clear for RDSEED, but it so far every processor released by Intel with SGX support also has RDSEED (including Gemini Lake).

cc @briansmith

Test capacity of ZST vector

Initially, rust-lang#50233 accidentally changed the capacity of empty ZST. This was pointed out during code review. This commit adds a test to prevent capacity of ZST vectors from accidentally changing to prevent that from happening again.

… r=alexcrichton

Use libbacktrace pretty-printing

r? @alexcrichton

fix rust-lang/rust issue rust-lang#50583

Rationale for the fix is in rust-lang#50583.  I've verified that before the fix /musl-armhf/lib/libc.a is riddled with the illegal variant of vmov.f64 and after the fix the version built doesn't contain any of these illegal instructions.

I originally thought that the arm-linux-gnueabi version also needed fixing - to add a -mfloat-abi-soft but that's unnecessary as it's compiled with the gnueabi (not hf) compiler (I've some a quick check that the libc.a produced doesn't include VFP instructions).

r? @alexcrichton

Add missing urls in ffi module docs

r? @QuietMisdreavus

…s-message, r=zackmdavis

Fix private_no_mangle_fns message grammar

Simply changes "an warning" to "a warning" in the `private_no_mangle_fns` warning. I started getting this in some code after upgrading to 1.31.0.

…osure-using-region-from-containing-fn, r=nikomatsakis

Add test of current behavior (infer free region within closure body)

This behavior was previously not encoded in our test suite.

it is pretty important that we test this behavior. In particular, in rust-lang#56537  I had proposed expanding the lifetime elision rules so that they would apply to some of the cases encoded in this test, which would cause them to start failing to compile successfully (because the lifetime attached to the return type would start being treated as connected to the lifetime on the input parameter to the lambda expression, which is explicitly *not* what the code wants in this particular case).

In other words, I am trying to ensure that anyone who tries such experiments with lifetime elision in the future quickly finds out why we don't support lifetime elision on lambda expressions (at least not in the naive manner described on rust-lang#56537).

…ckmdavis

target: remove Box returned by get_targets

Allow ptr::hash to accept fat pointers

Fat pointers implement Hash since rust-lang#45483.  This is a follow-up to rust-lang#56250.

…ertj

Account for `impl Trait` when suggesting lifetime

Fix rust-lang#56745

… r=kennytm

Add short emoji status to toolstate updates

I get a lot of these emails and it's good to know which ones I should be paying closer attention to -- i.e. the ones where clippy breaks. This adds a short emoji status report to the first line of the commit message, which shows up in notifications directly

I haven't been able to test it, and the actual emoji are just suggestions.

r? @kennytm

cc @rust-lang/infra @rust-lang/devtools

Deduplicate unsatisfied trait bounds

Fix rust-lang#35677.

Add x86_64-unknown-uefi target

This adds a new rustc target-configuration called 'x86_64-unknown_uefi'.
Furthermore, it adds a UEFI base-configuration to be used with other
targets supported by UEFI (e.g., i386, armv7hl, aarch64, itanium, ...).

UEFI systems provide a very basic operating-system environment, meant
to unify how systems are booted. It is tailored for simplicity and fast
setup, as it is only meant to bootstrap other systems. For instance, it
copies most of the ABI from Microsoft Windows, rather than inventing
anything on its own. Furthermore, any complex CPU features are
disabled. Only one CPU is allowed to be up, no interrupts other than
the timer-interrupt are allowed, no process-separation is performed,
page-tables are identity-mapped, ...

Nevertheless, UEFI has an application model. Its main purpose is to
allow operating-system vendors to write small UEFI applications that
load their kernel and terminate the UEFI system. However, many other
UEFI applications have emerged in the past, including network-boot,
debug-consoles, and more.

This UEFI target allows to compile rust code natively as UEFI
applications. No standard library support is added, but libcore can be
used out-of-the-box if a panic-handler is provided. Furthermore,
liballoc works as well, if a `GlobalAlloc` handler is provided. Both
have been tested with this target-configuration.

Note that full libstd support is unlikely to happen. While UEFI does
have standardized interfaces for networking and alike, none of these
are mandatory and they are unlikely to be shipped in common consumer
firmwares. Furthermore, several features like process-separation are
not available (or only in very limited fashion). Those parts of libstd
would have to be masked.

Fixes broken links

Just a few broken links.

Not sure what to do about this one: https://github.com/rust-lang/rust/blame/master/src/doc/unstable-book/src/language-features/plugin.md#L135 (regex macros were removed a while ago in rust-lang/regex@0375954).

Fix docs path to PermissionsExt

Couldn't test the link yet, since I didn't figure out how to build std rustdocs without building the entire compiler itself 🙂