… stabilized

I don't know how to test this. I confirmed locally that this gives the
appropriate help with `channel = "beta"`:

```
error[E0554]: `#![feature]` may not be used on the beta release channel
 --> src/lib.rs:2:1
  |
2 | #![feature(min_const_generics)]
  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: remove the attribute
  |
  = help: the feature `min_const_generics` has been stable since 1.51.0 and no longer requires an attribute to enable

error[E0554]: `#![feature]` may not be used on the beta release channel
 --> src/lib.rs:3:1
  |
3 | #![feature(min_const_generics, min_specialization)]
  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  |
  = help: the feature `min_const_generics` has been stable since 1.51.0 and no longer requires an attribute to enable

error[E0554]: `#![feature]` may not be used on the beta release channel
 --> src/lib.rs:4:1
  |
4 | #![feature(box_patterns)]
  | ^^^^^^^^^^^^^^^^^^^^^^^^^
```

Signed-off-by: Rustin-Liu <rustin.liu@gmail.com>

resolve conflicts

Co-authored-by: Mara Bos <m-ou.se@m-ou.se>

The default illumos shell ("sh" in the default PATH) is ksh93, rather
than bash, and does not support constructs like "local" that came from
bash.  The bootstrap function for invoking "install.sh" scripts should
use "bash" explicitly there to avoid issues.

This switches from JS-generated toggles to using the HTML <details> tag
for expanding and collapsing entries in the "Implementors" section.

This commit updates rustc, with an applicable LLVM version, to use
LLVM's new `llvm.fpto{u,s}i.sat.*.*` intrinsics to implement saturating
floating-point-to-int conversions. This results in a little bit tighter
codegen for x86/x86_64, but the main purpose of this is to prepare for
upcoming changes to the WebAssembly backend in LLVM where wasm's
saturating float-to-int instructions will now be implemented with these
intrinsics.

This change allows simplifying a good deal of surrounding code, namely
removing a lot of wasm-specific behavior. WebAssembly no longer has any
special-casing of saturating arithmetic instructions and the need for
`fptoint_may_trap` is gone and all handling code for that is now
removed. This means that the only wasm-specific logic is in the
`fpto{s,u}i` instructions which only get used for "out of bounds is
undefined behavior". This does mean that for the WebAssembly target
specifically the Rust compiler will no longer be 100% compatible with
pre-LLVM 12 versions, but it seems like that's unlikely to be relied on
by too many folks.

Note that this change does immediately regress the codegen of saturating
float-to-int casts on WebAssembly due to the specialization of the LLVM
intrinsic not being present in our LLVM fork just yet. I'll be following
up with an LLVM update to pull in those patches, but affects a few other
SIMD things in flight for WebAssembly so I wanted to separate this change.

Eventually the entire `cast_float_to_int` function can be removed when
LLVM 12 is the minimum version, but that will require sinking the
complexity of it into other backends such as Cranelfit.

…, r=eddyb,varkor

Rename AssociatedItems to AssocItems

Signed-off-by: Rustin-Liu <rustin.liu@gmail.com>

Part of rust-lang#60163 (comment)

…und_pair, r=m-ou-se

Implement indexing slices with pairs of core::ops::Bound<usize>

Closes rust-lang#49976.

I am not sure about code duplication between `check_range` and `into_maybe_range`. Should be former implemented in terms of the latter? Also this PR doesn't address code duplication between `impl SliceIndex for Range*`.

Added CharIndices::offset function

The CharIndices iterator has a field internally called front_offset, that I think would be very useful to have access to.

You can already do something like ``char_indices.next().map(|(offset, _)| offset)``, but that is wordy, in addition to not handling the case where the iterator has ended, where you'd want the offset to be equal to the length.

I'm very new to the open source world and the rust repository, so I'm sorry if I missed a step or did something weird.

On stable, suggest removing `#![feature]` for features that have been stabilized

I don't know how to test this (https://rust-lang.zulipchat.com/#narrow/stream/182449-t-compiler.2Fhelp/topic/Run.20tests.20without.20enabling.20nightly.20features.3F). I confirmed locally that this gives the
appropriate help with `channel = "beta"`:

```
error[E0554]: `#![feature]` may not be used on the beta release channel
 --> src/lib.rs:2:1
  |
2 | #![feature(min_const_generics)]
  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: remove the attribute
  |
  = help: the feature `min_const_generics` has been stable since 1.51.0 and no longer requires an attribute to enable

error[E0554]: `#![feature]` may not be used on the beta release channel
 --> src/lib.rs:3:1
  |
3 | #![feature(min_const_generics, min_specialization)]
  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  |
  = help: the feature `min_const_generics` has been stable since 1.51.0 and no longer requires an attribute to enable

error[E0554]: `#![feature]` may not be used on the beta release channel
 --> src/lib.rs:4:1
  |
4 | #![feature(box_patterns)]
  | ^^^^^^^^^^^^^^^^^^^^^^^^^
```

Closes rust-lang#83715.

Add a suggestion when using a type alias instead of trait alias

Fixes rust-lang#43913

r? ````@estebank````

implement `TrustedRandomAccess` for `Take` iterator adapter

`TrustedRandomAccess` requires the iterator length to fit within `usize`. `take(n)` only constrains the upper bound of an iterator. So if the inner is `TrustedRandomAccess` (which already implies a finite length) then so can be `Take`.

```@rustbot``` label T-libs-impl

Explicitly implement `!Send` and `!Sync` for `sys::{Args, Env}`

Remove the field `_dont_send_or_sync_me: PhantomData<*mut ()>` in favor of an explicit implementation of `!Send` and `!Sync`.

move core::hint::black_box under its own feature gate

The `black_box` function had its own RFC and is tracked separately from the `test` feature at rust-lang#64102. Let's reflect this in the feature gate.

To avoid breaking all the benchmarks, libtest's `test::black_box` is a wrapping definition, not a reexport -- this means it is still under the `test` feature gate.

…ark-Simulacrum

bootstrap: use bash on illumos to run install scripts

The default illumos shell ("sh" in the default PATH) is ksh93, rather
than bash, and does not support constructs like "local" that came from
bash.  The bootstrap function for invoking "install.sh" scripts should
use "bash" explicitly there to avoid issues.

…es, r=varkor

various const parameter defaults improvements

Actually resolve names in const parameter defaults, fixing `struct Foo<const N: usize = { usize::MAX }>`.

---
Split generic parameter ban rib for types and consts, allowing
```rust
#![feature(const_generics_defaults)]
struct Q;
struct Foo<T = Q, const Q: usize = 3>(T);
```

---
Remove the type/const ordering restriction if `const_generics_defaults` is active, even if `const_generics` is not. allowing us to stabilize and test const param defaults separately.

---
Check well formedness of const parameter defaults, eagerly emitting an error for `struct Foo<const N: usize = { 0 - 1 }>`

---
Do not forbid const parameters in param defaults, allowing `struct Foo<const N: usize, T = [u8; N]>(T)` and `struct Foo<const N: usize, const M: usize = N>`. Note that this should not change anything which is stabilized, as on stable, type parameters must be in front of const parameters, which means that type parameter defaults are only allowed if no const parameters exist.

We still forbid generic parameters inside of const param types.

r? ````@varkor```` ````@petrochenkov````

…earth,Nemo157,GuillaumeGomez

Use details tag for trait implementors.

Part of rust-lang#83332 and following on from rust-lang#83337 and rust-lang#83355.

This removes one category of JS-generated toggles (implementors), and replaces them with a `<details>` tag. This simplifies the JS, and fixes some bugs where things that were supposed to be hidden by the toggle were not hidden. Compare https://hoffman-andrews.com/rust/details-implementors/std/io/trait.Read.html#impl-Read vs https://doc.rust-lang.org/nightly/std/io/trait.Read.html#implementors.

This introduces a `left: -23px` to put the toggle in the correct place, matching the current style for `.collapse-toggle`.

It's worth noting this introduces a slight behavior change: since the entire line is now a `<summary>`, any part of the line is clickable. So for instance, in `impl Read for File`, clicking `impl` or `for` will collapse / expand the docs. Clicking `Read` or `File` still links to the appropriate documentation as before.

…gisa

rustc: Use LLVM's new saturating float-to-int intrinsics

This commit updates rustc, with an applicable LLVM version, to use
LLVM's new `llvm.fpto{u,s}i.sat.*.*` intrinsics to implement saturating
floating-point-to-int conversions. This results in a little bit tighter
codegen for x86/x86_64, but the main purpose of this is to prepare for
upcoming changes to the WebAssembly backend in LLVM where wasm's
saturating float-to-int instructions will now be implemented with these
intrinsics.

This change allows simplifying a good deal of surrounding code, namely
removing a lot of wasm-specific behavior. WebAssembly no longer has any
special-casing of saturating arithmetic instructions and the need for
`fptoint_may_trap` is gone and all handling code for that is now
removed. This means that the only wasm-specific logic is in the
`fpto{s,u}i` instructions which only get used for "out of bounds is
undefined behavior". This does mean that for the WebAssembly target
specifically the Rust compiler will no longer be 100% compatible with
pre-LLVM 12 versions, but it seems like that's unlikely to be relied on
by too many folks.

Note that this change does immediately regress the codegen of saturating
float-to-int casts on WebAssembly due to the specialization of the LLVM
intrinsic not being present in our LLVM fork just yet. I'll be following
up with an LLVM update to pull in those patches, but affects a few other
SIMD things in flight for WebAssembly so I wanted to separate this change.

Eventually the entire `cast_float_to_int` function can be removed when
LLVM 12 is the minimum version, but that will require sinking the
complexity of it into other backends such as Cranelfit.