Implement nonzero arithmetics for NonZero types.

Hello'all, this is my first PR to this repo.

Non-zero natural numbers are stable by addition/multiplication/exponentiation, so it makes sense to make this arithmetic possible with `NonZeroU*`.

The major pitfall is that overflowing underlying `u*` types possibly lead to underlying `0` values, which break the major invariant of `NonZeroU*`. To accommodate it, only `checked_` and `saturating_` operations are implemented.

Other variants allowing wrapped results like `wrapping_` or `overflowing_` are ruled out *de facto*.

`impl Add<u*> for NonZeroU* { .. }` was considered, as it panics on overflow which enforces the invariant, but it does not so in release mode. I considered forcing `NonZeroU*::add` to panic in release mode by deferring the check to `u*::checked_add`, but this is less explicit for the user than directly using `NonZeroU*::checked_add`.
Following `@Lokathor's` advice on zulip, I have dropped the idea.

`@poliorcetics` on Discord also suggested implementing `_sub` operations, but I'd postpone this to another PR if there is a need for it. My opinion is that it could be useful in some cases, but that it makes less sense because non-null natural numbers are not stable by subtraction even in theory, while the overflowing problem is just about technical implementation.

One thing I don't like is that the type of the `other` arg differs in every implementation: `_add` methods accept any raw positive integer, `_mul` methods only accept non-zero values otherwise the invariant is also broken, and `_pow` only seems to accept `u32` for a reason I ignore but that seems consistent throughout `std`. Maybe there is a better way to harmonize this?

This is it, Iope I haven't forgotten anything and I'll be happy to read your feedback.

Do not suggest to add type annotations for unnameable types

Consider this example:
```rust
const A = || 42;

struct S<T> { t: T }
const B: _ = S { t: || 42 };
```
This currently produces the following output:
```
error: missing type for `const` item
 --> src/lib.rs:1:7
  |
1 | const A = || 42;
  |       ^ help: provide a type for the item: `A: [closure@src/lib.rs:1:11: 1:16]`

error[E0121]: the type placeholder `_` is not allowed within types on item signatures
 --> src/lib.rs:4:10
  |
4 | const B: _ = S { t: || 42 };
  |          ^
  |          |
  |          not allowed in type signatures
  |          help: replace `_` with the correct type: `S<[closure@src/lib.rs:4:21: 4:26]>`

error: aborting due to 2 previous errors
```
However, these suggestions are obviously useless, because the suggested types cannot be written down. With my changes, the suggestion is replaced with a note, because there is no simple fix:
```
error: missing type for `const` item
 --> test.rs:1:7
  |
1 | const A = || 42;
  |       ^
  |
note: however, the inferred type `[closure@test.rs:1:11: 1:16]` cannot be named
 --> test.rs:1:11
  |
1 | const A = || 42;
  |           ^^^^^

error[E0121]: the type placeholder `_` is not allowed within types on item signatures
 --> test.rs:4:10
  |
4 | const B: _ = S { t: || 42 };
  |          ^ not allowed in type signatures
  |
note: however, the inferred type `S<[closure@test.rs:4:21: 4:26]>` cannot be named
 --> test.rs:4:14
  |
4 | const B: _ = S { t: || 42 };
  |              ^^^^^^^^^^^^^^

error: aborting due to 2 previous errors
```

const_eval_checked: Support as casts in abstract consts

Hash DefId in rustc_span.

This is mostly just moving code around. Changes are simplifications of unneeded callbacks from rustc_span to rustc_middle.

r? `@petrochenkov`

Bump to 1.55

r? `@Mark-Simulacrum`

Rollup of 7 pull requests

Successful merges:

 - #85800 (Fix some diagnostic issues with const_generics_defaults feature gate)
 - #85823 (Do not suggest ampmut if rhs is already mutable)
 - #86153 (Print dummy spans as `no-location`)
 - #86174 (Detect incorrect vtable alignment during const eval)
 - #86189 (Make `relate_type_and_mut` public)
 - #86205 (Run full const-generics test for issue-72293)
 - #86217 (Remove "generic type" in boxed.rs)

Failed merges:

r? `@ghost`
`@rustbot` modify labels: rollup

Remove "generic type" in boxed.rs

r? ``@m-ou-se``

Run full const-generics test for issue-72293

Closes #72293
r? ```@oli-obk```

Make `relate_type_and_mut` public

#85343 improved diagnostics around `Relate` impls but made `relate_type_and_mut` private, which was accessible as `relate` previously. This makes it public so that we can use it on rust-semverver.

r? ```@Aaron1011```

Detect incorrect vtable alignment during const eval

This PR fixes #86132 by detecting invalid alignment values for trait objects in the interpreter, and emitting an error about this conversion failure, to avoid the ICE.

I've noticed that the error emitted at https://github.com/rust-lang/rust/blob/a50d72158e08e02cfc051b863017bdbd2c45b637/compiler/rustc_mir/src/interpret/traits.rs#L163-L166 doesn't seem to be present in the const-ub tests, so I've tried adding a test that triggers both of these cases: one for the invalid size, and another for the invalid alignment that #86132 tracks (I have found different magic values triggering different `Align::from_bytes` errors than the "power of 2" one, if need be).

However, when doing that, I *cannot* for the life of me figure out the correct incantation to make these 2 errors trigger with the "it is undefined behavior to use this value" message rather than the "any use of this value will cause an error" lint.

I've tried Oli's suggestions of different values, tuples and arrays, using the transparent wrapper trick from the other tests and I was only able to trigger the regular const-ub errors about the size of the vtable, or that the drop pointer was invalid. Maybe these "type validation failed" errors happen before this part of the interpreter is reached and there just needs some magic incorrect values to bypass them, I don't know.

Since this fixes an ICE, and if the constants are indeed used, these 2 tests will turn into a hard error, I thought I'd open the PR anyways. And if ```@RalfJung``` you know of a way I could manage that (if you think that these tests are worth checking that the `throw_ub_format!` does indeed create const-ub errors as we expect) I'd be grateful.

For that reason, r? ```@RalfJung``` and cc ```@oli-obk.```

Print dummy spans as `no-location`

Fixes #58808.

Do not suggest ampmut if rhs is already mutable

Removes invalid suggestion in #85765, although it should highlight the user type instead of the local variable.

Looking at the comments of this line:
https://github.com/rust-lang/rust/blob/84b1005bfd22e2cb2a4c13b0b81958fe72628354/compiler/rustc_mir_build/src/build/matches/mod.rs#L2107

It was intentionally set to `None`, causing it to highlight the local variable instead. I am not sure if I will be able to fix it.

Fixes #85765

Fix some diagnostic issues with const_generics_defaults feature gate

This PR makes a few changes:
- print out const param defaults in "lifetime ordering" errors rather than discarding them
- update `is_simple_text` to account for const params when checking if a type has no generics, this was causing a note to be failed to add to an error message
- fixes some diagnostic wording that incorrectly said there was ordering restrictions between type/const params despite the `const_generics_defaults` feature gate is active

Don't use a generator for BoxedResolver

The generator is non-trivial and requires unsafe code anyway. Using regular unsafe code without a generator is much easier to follow.

Based on #85810 as it touches rustc_interface too.

Suggest a trailing comma if a 1-tuple is expected and a parenthesized expression is found

This pull request fixes #86100. The following code:
```rust
fn main() {
    let t: (i32,) = (1);
}
```
currently produces:
```
warning: unnecessary parentheses around assigned value
 --> test.rs:2:21
  |
2 |     let t: (i32,) = (1);
  |                     ^^^ help: remove these parentheses
  |
  = note: `#[warn(unused_parens)]` on by default

error[E0308]: mismatched types
 --> test.rs:2:21
  |
2 |     let t: (i32,) = (1);
  |            ------   ^^^ expected tuple, found integer
  |            |
  |            expected due to this
  |
  = note: expected tuple `(i32,)`
              found type `{integer}`

error: aborting due to previous error; 1 warning emitted
```
With my changes, I get the same warning and the following error:
```
error[E0308]: mismatched types
 --> test.rs:2:21
  |
2 |     let t: (i32,) = (1);
  |            ------   ^^^ expected tuple, found integer
  |            |
  |            expected due to this
  |
  = note: expected tuple `(i32,)`
              found type `{integer}`
help: use a trailing comma to create a tuple with one element
  |
2 |     let t: (i32,) = (1,);
  |                     ^^^^
```
i.e. I have added a suggestion to add a trailing comma to create a 1-tuple. This suggestion is only issued if a 1-tuple is expected and the expression (`(1)` in the example above) is surrounded by parentheses and does not already have a tuple type. In this situation, I'd say that it is pretty likely that the user meant to create a tuple.

Disallow non-monomorphic calls to `needs_drop` in interpreter

otherwise evaluation could change after further substitutions.

std: Stabilize wasm simd intrinsics

This commit performs two changes to stabilize Rust support for
WebAssembly simd intrinsics:

* The stdarch submodule is updated to pull in rust-lang/stdarch#1179.
* The `wasm_target_feature` feature gate requirement for the `simd128`
  feature has been removed, stabilizing the name `simd128`.

This should conclude the FCP started on #74372 and...

Closes #74372

This commit performs two changes to stabilize Rust support for
WebAssembly simd intrinsics:

* The stdarch submodule is updated to pull in rust-lang/stdarch#1179.
* The `wasm_target_feature` feature gate requirement for the `simd128`
  feature has been removed, stabilizing the name `simd128`.

This should conclude the FCP started on #74372 and...

Closes #74372

MVP for using rust-lld as part of cc

Will fix #71519. I need to figure out how to write a test showing that lld is used instead of whatever linker cc normally uses. When I manually run rustc using `echo 'fn main() {}' | RUSTC_LOG=rustc_codegen_ssa::back::link=debug ./rustc -Clinker-flavor=gcc-lld --crate-type bin -Clink-arg=-Wl,-v` (thanks to bjorn3 on Zulip), I can see that lld is used, but I'm not sure how to inspect that output in a test.

to_digit simplification (less jumps)

I just realised we might be able to make use of the fact that changing case in ascii is easy to help simplify to_digit some more.

It looks a bit cleaner and it looks like it's less jumps and there's less instructions in the generated assembly:

https://godbolt.org/z/84Erh5dhz

The benchmarks don't really tell me much. Maybe a slight improvement on the var radix.

Before:
```
test char::methods::bench_to_digit_radix_10                     ... bench:      53,819 ns/iter (+/- 8,314)
test char::methods::bench_to_digit_radix_16                     ... bench:      57,265 ns/iter (+/- 10,730)
test char::methods::bench_to_digit_radix_2                      ... bench:      55,077 ns/iter (+/- 5,431)
test char::methods::bench_to_digit_radix_36                     ... bench:      56,549 ns/iter (+/- 3,248)
test char::methods::bench_to_digit_radix_var                    ... bench:      43,848 ns/iter (+/- 3,189)

test char::methods::bench_to_digit_radix_10                     ... bench:      51,707 ns/iter (+/- 10,946)
test char::methods::bench_to_digit_radix_16                     ... bench:      52,835 ns/iter (+/- 2,689)
test char::methods::bench_to_digit_radix_2                      ... bench:      51,012 ns/iter (+/- 2,746)
test char::methods::bench_to_digit_radix_36                     ... bench:      53,210 ns/iter (+/- 8,645)
test char::methods::bench_to_digit_radix_var                    ... bench:      40,386 ns/iter (+/- 4,711)

test char::methods::bench_to_digit_radix_10                     ... bench:      54,088 ns/iter (+/- 5,677)
test char::methods::bench_to_digit_radix_16                     ... bench:      55,972 ns/iter (+/- 17,229)
test char::methods::bench_to_digit_radix_2                      ... bench:      52,083 ns/iter (+/- 2,425)
test char::methods::bench_to_digit_radix_36                     ... bench:      54,132 ns/iter (+/- 1,548)
test char::methods::bench_to_digit_radix_var                    ... bench:      41,250 ns/iter (+/- 5,299)
```
After:
```
test char::methods::bench_to_digit_radix_10                     ... bench:      48,907 ns/iter (+/- 19,449)
test char::methods::bench_to_digit_radix_16                     ... bench:      52,673 ns/iter (+/- 8,122)
test char::methods::bench_to_digit_radix_2                      ... bench:      48,509 ns/iter (+/- 2,885)
test char::methods::bench_to_digit_radix_36                     ... bench:      50,526 ns/iter (+/- 4,610)
test char::methods::bench_to_digit_radix_var                    ... bench:      38,618 ns/iter (+/- 3,180)

test char::methods::bench_to_digit_radix_10                     ... bench:      54,202 ns/iter (+/- 6,994)
test char::methods::bench_to_digit_radix_16                     ... bench:      56,585 ns/iter (+/- 8,448)
test char::methods::bench_to_digit_radix_2                      ... bench:      50,548 ns/iter (+/- 1,674)
test char::methods::bench_to_digit_radix_36                     ... bench:      52,749 ns/iter (+/- 2,576)
test char::methods::bench_to_digit_radix_var                    ... bench:      40,215 ns/iter (+/- 3,327)

test char::methods::bench_to_digit_radix_10                     ... bench:      50,233 ns/iter (+/- 22,272)
test char::methods::bench_to_digit_radix_16                     ... bench:      50,841 ns/iter (+/- 19,981)
test char::methods::bench_to_digit_radix_2                      ... bench:      50,386 ns/iter (+/- 4,555)
test char::methods::bench_to_digit_radix_36                     ... bench:      52,369 ns/iter (+/- 2,737)
test char::methods::bench_to_digit_radix_var                    ... bench:      40,417 ns/iter (+/- 2,766)
```

I removed the likely as it resulted in a few less instructions. (It's not been in there long - I added it in the last to_digit iteration).

Allow qualified paths in struct construction (both expressions and patterns)

Fixes #79658

Add the x86_64-gnu-stable builder

During the 1.52 release process we had to deal with some commits that passed the test suite on the nightly branch but failed on the beta or stable branch. In that case it was due to some UI tests including the channel name in the output, but other changes might also be dependent on the channel.

This commit adds a new CI job that runs the Linux x86_64 test suite with the stable branch, ensuring nightly changes also work as stable. To ensure the new job works the following other changes are present:

* The `ui-fulldeps/session-derive-errors.rs` test has been disabled on beta and stable, which required adding support for `// ignore-{channel}` and `// only-{channel}`.
* The `rustdoc/intra-doc/field.rs` has been fixed.

r? `@Mark-Simulacrum`
fixes https://github.com/rust-lang/release-team/issues/11

Disable the machine outliner by default

This addresses a codegen-issue that needs to be fixed upstream in LLVM.
While we wait for the fix, we can disable it.

Verified manually that the outliner is no longer run when
`-Copt-level=z` is specified, and also that you can override this with
`-Cllvm-args=-enable-machine-outliner` if you need it anyway.

A regression test is not really feasible in this instance, given that we
do not have any minimal reproducers.

Fixes #85351

cc `@pnkfelix`

Don't pass -Z unstable-options by default for UI tests

Unconditionally passing -Z unstable-options makes it impossible to test whether an option requires unstable-options or not.

This uncovered quite a lot of bugs, I'll open issues for each. These don't strictly need to be fixed before this is merged, it just makes the diff much larger because of the changes to diagnostics.

- https://github.com/rust-lang/rust/issues/82636
- https://github.com/rust-lang/rust/issues/82637
- https://github.com/rust-lang/rust/issues/82638

position.

Use preorder traversal when checking for SSA locals

Traverse blocks in topological sort of dominance partial order, to ensure that
local analyzer correctly identifies locals that are already in static single
assignment form, while avoiding dependency on implicit numeric order of blocks.

When rebuilding the standard library, this change reduces the number of locals
that require an alloca from 62452 to 62348.

ignore test if rust-lld not found

create ld -> rust-lld symlink at build time instead of run time

for testing in ci

copy instead of symlinking

remove linux check

test for linker, suggestions from bjorn3

fix overly restrictive lld matcher

use -Zgcc-ld flag instead of -Clinker-flavor

refactor code adding lld to gcc path

revert ci changes

suggestions from petrochenkov

rename gcc_ld to gcc-ld in dirs

Rollup of 7 pull requests

Successful merges:

 - #82037 (Make symbols stripping work on MacOS X)
 - #84687 (Multiple improvements to RwLocks)
 - #85997 (rustdoc: Print a warning if the diff when comparing to old nightlies is empty)
 - #86051 (Updated code examples and wording in move keyword documentation )
 - #86111 (fix off by one in `std::iter::Iterator` documentation)
 - #86113 (build doctests with lld if use-lld = true)
 - #86175 (update Miri)

Failed merges:

r? `@ghost`
`@rustbot` modify labels: rollup