There is no idx in the function signature.

As the comment says, this lint "is mostly historical, and not
particularly useful". It's not worth keeping it around.

The docs for the LoongArch targets are a bit dated since their
introduction, and the prose has some room for improvement as well.
Streamline a bit, referring to the neighboring targets' docs, and
provide up-to-date information as much as I can come up with.

the `expose_provenance` method does not require `T: Sized`

The new enum `DeclareLetBindings` has three variants:
- `Yes`: Declare `let` bindings as normal, for `if` conditions.
- `No`: Don't declare bindings, for match guards and let-else.
- `LetNotPermitted`: Assert that `let` expressions should not occur.

The previous boolean used `true` to indicate that storage-live should _not_ be
emitted, so all occurrences of `Yes` and `No` should be the logical opposite of
the previous value.

These particular callers don't actually use the returned macro information, so
they can use a simpler span-unexpansion function that doesn't return it.

compiler should not suggest nonsensical signatures, original suggestion was

error[E0308]: mismatched types
 --> src/lib.rs:3:31
  |
3 | fn select<F, I>(filter: F) -> Select<F, I> {
  |    ------                     ^^^^^^^^^^^^ expected `Select<F, I>`, found `()`
  |    |
  |    implicitly returns `()` as its body has no tail or `return` expression
  |
  = note: expected struct `Select<F, I>`
          found unit type `()`

error[E0282]: type annotations needed for `Select<{closure@src/lib.rs:8:22: 8:25}, I>`
 --> src/lib.rs:8:9
  |
8 |     let lit = select(|x| match x {
  |         ^^^
  |
help: consider giving `lit` an explicit type, where the type for type parameter `I` is specified
  |
8 |     let lit: Select<{closure@src/lib.rs:8:22: 8:25}, I> = select(|x| match x {
  |            ++++++++++++++++++++++++++++++++++++++++++++

Some errors have detailed explanations: E0282, E0308.
For more information about an error, try `rustc --explain E0282`.

…r=lcnr

Remove the `box_pointers` lint.

As the comment says, this lint "is mostly historical, and not particularly useful". It's not worth keeping it around.

r? ``@estebank``

…umentation, r=Amanieu

Fix simd_gather documentation

There is no idx in the function signature.

Replace some magic booleans in match-lowering with enums

This PR takes some boolean arguments used by the match-lowering code, and replaces them with dedicated enums that more clearly express their effect, while also making it much easier to find how each value is ultimately used.

Update test comment

r? `@camelid`

Rewrote this comment since it mixed up a/b in one place and was generally a bit confusing

…eb,heiher

Update the LoongArch target documentation

The docs for the LoongArch targets are a bit dated since their introduction, and the prose has some room for improvement as well. Streamline a bit, referring to the neighboring targets' docs, and provide up-to-date information as much as I can come up with.

cc fellow target maintainer `@heiher` for review of target-specific bits

…trieb

small correction to fmt::Pointer impl

~~The `addr` method does not require `T: Sized`, and is preferred for use over `expose_provenance`.~~
`expose_provenance` does not require `T: Sized`.

coverage: Avoid getting extra unexpansion info when we don't need it

Several callers of `unexpand_into_body_span_with_visible_macro` would immediately discard the additional macro-related information, which is wasteful. We can avoid this by having them instead call a simpler method that just returns the span they care about.

This PR also moves the relevant functions out of `coverage::spans::from_mir` and into a new submodule `coverage::unexpand`, so that calling them from `coverage::mappings` is less awkward.

There should be no actual changes to coverage-instrumentation output, as demonstrated by the absence of test updates.

Add a regression test for rust-lang#123630

Fixes rust-lang#123630

compiler should not suggest nonsensical signatures, original suggestion was

```
error[E0308]: mismatched types
 --> src/lib.rs:3:31
  |
3 | fn select<F, I>(filter: F) -> Select<F, I> {
  |    ------                     ^^^^^^^^^^^^ expected `Select<F, I>`, found `()`
  |    |
  |    implicitly returns `()` as its body has no tail or `return` expression
  |
  = note: expected struct `Select<F, I>`
          found unit type `()`

error[E0282]: type annotations needed for `Select<{closure@src/lib.rs:8:22: 8:25}, I>`
 --> src/lib.rs:8:9
  |
8 |     let lit = select(|x| match x {
  |         ^^^
  |
help: consider giving `lit` an explicit type, where the type for type parameter `I` is specified
  |
8 |     let lit: Select<{closure@src/lib.rs:8:22: 8:25}, I> = select(|x| match x {
  |            ++++++++++++++++++++++++++++++++++++++++++++

Some errors have detailed explanations: E0282, E0308. For more information about an error, try `rustc --explain E0282`.
```

…gs, r=Kobzol

Improve `run-make-support` library `args` API

It allows to pass both `Vec` and slices, which makes it much better (for me at least 😉).

r? ``@Kobzol``