Handle build completion message from Cargo

This was introduced in the recent bump to 1.44 bootstrap cargo

Fixes #71561.

Add a convenience method on `TyCtxt` for checking for thread locals

This PR extracts the cleanup part of #71192

r? @bjorn3

Vec drop and truncate: drop using raw slice *mut [T]

By creating a *mut [T] directly (without going through &mut [T]), avoid
questions of validity of the contents of the slice.

Consider the following risky code:

```rust
unsafe {
    let mut v = Vec::<bool>::with_capacity(16);
    v.set_len(16);
}
```

The intention is that with this change, we avoid one of the soundness
questions about the above snippet, because Vec::drop no longer
produces a mutable slice of the vector's contents.

r? @RalfJung

Rollup of 5 pull requests

Successful merges:

 - #70950 (extend NLL checker to understand `'empty` combined with universes)
 - #71433 (Add help message for missing right operand in condition)
 - #71449 (Move `{Free,}RegionRelations` and `FreeRegionMap` to `rustc_infer`)
 - #71559 (Detect git version before attempting to use --progress)
 - #71597 (Rename Unique::empty() -> Unique::dangling())

Failed merges:

r? @ghost

Rename Unique::empty() -> Unique::dangling()

A `FIXME` comment in `src/libcore/ptr/unique.rs` suggested refactoring `Unique::empty()` to `Unique::dangling()` which this PR does.

Detect git version before attempting to use --progress

Otherwise each update is run twice and errors are printed

I've tested this with:
git version 2.8.2.windows.1 (Windows)
git version 2.26.2.266.ge870325ee8 (Linux built from source)
git version 2.17.1 (Linux)
git version 2.21.1 (Apple Git-122.3) (MacOS)

I've tested with Python 2.7 (Windows, Linux, MacOS), 3.6 (Linux), and 3.7 (MacOS)

Move `{Free,}RegionRelations` and `FreeRegionMap` to `rustc_infer`

...and out of `rustc_middle`. This is to further #65031, albeit in a very minor way

r? @Mark-Simulacrum

Add help message for missing right operand in condition

closes #30035

extend NLL checker to understand `'empty` combined with universes

This PR extends the NLL region checker to understand `'empty` combined with universes. In particular, it means that the NLL region checker no longer considers `exists<R2> { forall<R1> { R1: R2 } }` to be provable. This is work towards https://github.com/rust-lang/rust/issues/59490, but we're not all the way there. One thing in particular it does not address is error messages.

The modifications to the NLL region inference code turned out to be simpler than expected. The main change is to require that if `R1: R2` then `universe(R1) <= universe(R2)`.

This constraint follows from the region lattice (shown below), because we assume then that `R2` is "at least" `empty(Universe(R2))`, and hence if `R1: R2` (i.e., `R1 >= R2` on the lattice) then `R1` must be in some universe that can name `'empty(Universe(R2))`, which requires that `Universe(R1) <= Universe(R2)`.

```
static ----------+-----...------+       (greatest)
|                |              |
early-bound and  |              |
free regions     |              |
|                |              |
scope regions    |              |
|                |              |
empty(root)   placeholder(U1)   |
|            /                  |
|           /         placeholder(Un)
empty(U1) --         /
|                   /
...                /
|                 /
empty(Un) --------                      (smallest)
```

I also made what turned out to be a somewhat unrelated change to add a special region to represent `'empty(U0)`, which we use (somewhat hackily) to indicate well-formedness checks in some parts of the compiler. This fixes #68550.

I did some investigation into fixing the error message situation. That's a bit trickier: the existing "nice region error" code around placeholders relies on having better error tracing than NLL currently provides, so that it knows (e.g.) that the constraint arose from applying a trait impl and things like that. I feel like I was hoping *not* to do such fine-grained tracing in NLL, and it seems like we...largely...got away with that. I'm not sure yet if we'll have to add more tracing information or if there is some sort of alternative.

It's worth pointing out though that I've not kind of shifted my opinion on whose job it should be to enforce lifetimes: I tend to think we ought to be moving back towards *something like* the leak-check (just not the one we *had*). If we took that approach, it would actually resolve this aspect of the error message problem, because we would be resolving 'higher-ranked errors' in the trait solver itself, and hence we wouldn't have to thread as much causal information back to the region checker. I think it would also help us with removing the leak check while not breaking some of the existing crates out there.

Regardless, I think it's worth landing this change, because it was relatively simple and it aligns the set of programs that NLL accepts with those that are accepted by the main region checker, and hence should at least *help* us in migration (though I guess we still also have to resolve the existing crates that rely on leak check for coherence).

r? @matthewjasper

ci: use bash when executing the "bors build finished" jobs

We don't clone the repository in those builders, so the default shell (`src/ci/exec-with-shell.py`) is not present there. This fixes a GHA regression introduced in #71434.

r? @Mark-Simulacrum

Rollup of 5 pull requests

Successful merges:

 - #71205 (rustc: fix check_attr() for methods, closures and foreign functions)
 - #71540 (Suggest deref when coercing `ty::Ref` to `ty::RawPtr`)
 - #71655 (Miri: better document and fix dynamic const pattern soundness checks)
 - #71672 (document missing stable counterparts of intrinsics)
 - #71692 (Add clarification on std::cfg macro docs v. #[cfg] attribute)

Failed merges:

r? @ghost

Add clarification on std::cfg macro docs v. #[cfg] attribute

The wording was discussed, to a limited degree in #71679.  This tries to
address some confusion I as well as someone else had independently when
looking at this macro.

Fixes #71679

document missing stable counterparts of intrinsics

Notes the stable counterpart of each intrinsic in case one exists.

Implements #34338

r? @Dylan-DPC

Miri: better document and fix dynamic const pattern soundness checks

https://github.com/rust-lang/const-eval/issues/42 got me thinking about soundness for consts being used in patterns, and I found a hole in our existing dynamic checks: a const referring to a mutable static *in a different crate* was not caught. This PR fixes that. It also adds some comments that explain which invariants are crucial for soundness of const-patterns.

Curiously, trying to weaponize this soundness hole failed: pattern matching compilation ICEd when encountering the cross-crate static, saying "expected allocation ID alloc0 to point to memory". I don't know why that would happen, statics *should* be entirely normal memory for pattern matching to access.

r? @oli-obk
Cc @rust-lang/wg-const-eval

Suggest deref when coercing `ty::Ref` to `ty::RawPtr`

Fixes #32122

Currently we do autoderef when casting `ty::Ref` ->`ty::Ref`, but we don't autoderef when casting `ty::Ref` -> `ty::RawPtr`. This PR make the compiler suggests deref when coercing `ty::Ref` to `ty::RawPtr`

rustc: fix check_attr() for methods, closures and foreign functions

This fixes an issue that previously turned up for methods in https://github.com/rust-lang/rust/pull/69274, but also exists for closures and foreign function: `check_attr` does not call `codegen_fn_attrs()` for these types when it should, meaning that incorrectly used function attributes are not diagnosed without codegen.

The issue affects our UI tests, as they run with `--emit=metadata` by default, but as it turns out, this is not the only case: Function attributes are not checked on any dead code without this fix!

This makes the fix a **breaking change**. The following very silly Rust programs compiles fine on stable Rust when it should not, which is fixed by this PR.
```rust
fn main() {
    #[target_feature(enable = "sse2")]
    || {};
}
```

I assume any real-world program which may trigger this issue would at least emit a dead code warning, but of course that is no guarantee that such code does not exist...

Fixes #70307

rename-unique: Change calls and doc in raw_vec.rs

rename-unique: Change empty() -> dangling() in const-ptr-unique-rpass.rs

Remove -Z no-landing-pads flag

Since #67502, `-Z no-landing-pads` will cause all attempted unwinds to abort since we don't generate a `try` / `catch`. This previously worked because `__rust_try` was located in libpanic_unwind which is always compiled with `-C panic=unwind`, but `__rust_try` is now directly inline into the crate that uses `catch_unwind`.

As such, `-Z no-landing-pads` is now mostly useless and people should use `-C panic=abort` instead.

update Miri

Fixes https://github.com/rust-lang/rust/issues/71632
r? @ghost
Cc @rust-lang/miri

Store LLVM bitcode in object files, not compressed

This commit is an attempted resurrection of #70458 where LLVM bitcode
emitted by rustc into rlibs is stored into object file sections rather
than in a separate file. The main rationale for doing this is that when
rustc emits bitcode it will no longer use a custom compression scheme
which makes it both easier to interoperate with existing tools and also
cuts down on compile time since this compression isn't happening.

The blocker for this in #70458 turned out to be that native linkers
didn't handle the new sections well, causing the sections to either
trigger bugs in the linker or actually end up in the final linked
artifact. This commit attempts to address these issues by ensuring that
native linkers ignore the new sections by inserting custom flags with
module-level inline assembly.

Note that this does not currently change the API of the compiler at all.
The pre-existing `-C bitcode-in-rlib` flag is co-opted to indicate
whether the bitcode should be present in the object file or not.

Finally, note that an important consequence of this commit, which is also
one of its primary purposes, is to enable rustc's `-Clto` bitcode
loading to load rlibs produced with `-Clinker-plugin-lto`. The goal here
is that when you're building with LTO Cargo will tell rustc to skip
codegen of all intermediate crates and only generate LLVM IR. Today
rustc will generate both object code and LLVM IR, but the object code is
later simply thrown away, wastefully.

Rollup of 6 pull requests

Successful merges:

 - #71507 (Document unsafety in core::ptr)
 - #71572 (test iterator chain type length blowup)
 - #71617 (Suggest `into` instead of `try_into` if possible with int types)
 - #71627 (Fix wrong argument in autoderef process)
 - #71678 (Add an index page for nightly rustc docs.)
 - #71680 (Fix doc link to Eq trait from PartialEq trait)

Failed merges:

 - #71597 (Rename Unique::empty() -> Unique::dangling())

r? @ghost

Co-Authored-By: Nkennytm <kennytm@gmail.com>

This commit is an attempted resurrection of #70458 where LLVM bitcode
emitted by rustc into rlibs is stored into object file sections rather
than in a separate file. The main rationale for doing this is that when
rustc emits bitcode it will no longer use a custom compression scheme
which makes it both easier to interoperate with existing tools and also
cuts down on compile time since this compression isn't happening.

The blocker for this in #70458 turned out to be that native linkers
didn't handle the new sections well, causing the sections to either
trigger bugs in the linker or actually end up in the final linked
artifact. This commit attempts to address these issues by ensuring that
native linkers ignore the new sections by inserting custom flags with
module-level inline assembly.

Note that this does not currently change the API of the compiler at all.
The pre-existing `-C bitcode-in-rlib` flag is co-opted to indicate
whether the bitcode should be present in the object file or not.

Finally, note that an important consequence of this commit, which is also
one of its primary purposes, is to enable rustc's `-Clto` bitcode
loading to load rlibs produced with `-Clinker-plugin-lto`. The goal here
is that when you're building with LTO Cargo will tell rustc to skip
codegen of all intermediate crates and only generate LLVM IR. Today
rustc will generate both object code and LLVM IR, but the object code is
later simply thrown away, wastefully.

The wording was discussed, to a limited degree in #71679.  This tries to
address some confusion I as well as someone else had independently when
looking at this macro.

Fixes #71679

Fix doc link to Eq trait from PartialEq trait

The `Eq` link was incorrectly going to the `eq` method of `PartialEq`
instead of to the `Eq` trait.

Add an index page for nightly rustc docs.

This adds an `index.html` page at the root of the nightly-rustc docs so that the URL https://doc.rust-lang.org/nightly/nightly-rustc/ should have a landing page that lists all the crates.

Fix wrong argument in autoderef process

The `overloaded_deref_ty` is a function for derefencing a type which overloads the `Deref` trait. But actually this function never uses the parameter pushed in until this PR. -_-

Suggest `into` instead of `try_into` if possible with int types

If it is possible to convert an integer type into another using `into`, don't suggest `try_into`. This commit changes the suggested method to convert from one integer type to another for the following cases:

- u{n} -> i{m} where n < m
- u8 -> isize
- i{n} -> isize where n <= 16
- u{n} -> usize where n <= 16

Fixes #71580

test iterator chain type length blowup

Adds a regression test. closes #58952

r? @Dylan-DPC

Document unsafety in core::ptr

Contributes to #66219

I have yet to document all the `unsafe` blocks in the lib and would like to know if I'm headed in the right direction

r? @steveklabnik

Update Clippy

Fixes #71608

The `Eq` link was incorrectly going to the `eq` method of `PartialEq`
instead of to the `Eq` trait.

We don't clone the repository in those builders, so the default shell
(src/ci/exec-with-shell.py) is not present there.