Previously, the compiler didn't suggest similarly named associated items
unlike we do in many situations. This patch adds such diagnostics for
associated functions, types and constants.

The reference automatically coerces to a pointer. Writing an explicit
cast here is slightly misleading because that's most commonly used when
a pointer needs to be converted from one pointer type to another, e.g.
`*const c_void` to `*const sigaction` or vice versa.

In function arguments and let bindings, do not suggest changing `C` to `Foo::C`
unless `C` is the only variant of `Foo`, because it won't work.

The general warning is still kept, because code like this is confusing.

Fixes rust-lang#88730

…ger special case

Downloading LLVM from CI works for all platforms now.

Fix ICE when `start` lang item has wrong generics

In my previous pr rust-lang#87875 I missed the requirements on the `start` lang item due to its relative difficulty to test and opting for more conservative estimates.  This fixes that by updating the requirement to be exactly one generic type.

The `start` lang item should have exactly one generic type for the return type of the `main` fn ptr passed to it.  I believe having zero would previously *sometimes* compile (often with the use of `fn() -> ()` as the fn ptr but it was likely UB to call if the return type of `main` was not `()` as far as I know) however it also sometimes would not for various errors including ICEs and LLVM errors depending on exact situations.  Having more than 1 generic has always failed with an ICE because only the one generic type is expected and provided.

Fixes rust-lang#79559, fixes rust-lang#73584, fixes rust-lang#83117 (all duplicates)
Relevant to rust-lang#9307

r? ``@cjgillot``

…petrochenkov

Add `pie` as another `relocation-model` value

MCP: rust-lang/compiler-team#461

Use `libc::sigaction()` instead of `sys::signal()` to prevent a deadlock

Fixes rust-lang#88585. POSIX [specifies](https://man7.org/linux/man-pages/man3/fork.3p.html) that after forking,
> to avoid errors, the child process may only execute async-signal-safe operations until such time as one of the exec functions is called.

Rust's standard library does not currently adhere to this, as evidenced by rust-lang#88585. The child process calls [`sys::signal()`](https://github.com/rust-lang/rust/blob/7bf0736e130e2203c58654f7353dbf9575e49d5c/library/std/src/sys/unix/android.rs#L76), which on Android calls [`libc::dlsym()`](https://github.com/rust-lang/rust/blob/7bf0736e130e2203c58654f7353dbf9575e49d5c/library/std/src/sys/unix/weak.rs#L101), which is [**not**](https://man7.org/linux/man-pages/man7/signal-safety.7.html) async-signal-safe, and in fact causes a deadlock in the example in rust-lang#88585.

I think the easiest solution here would be to just call `libc::sigaction()` instead, which [is](https://man7.org/linux/man-pages/man7/signal-safety.7.html) async-signal-safe, provides the functionality we need, and is apparently available on all Android versions because it is also used e.g. [here](https://github.com/rust-lang/rust/blob/7bf0736e130e2203c58654f7353dbf9575e49d5c/library/std/src/sys/unix/stack_overflow.rs#L112-L114).

Resolve infered types when complaining about unexpected call type

```
error[E0618]: expected function, found `{integer}`
  --> $DIR/call-block.rs:2:13
   |
LL |     let _ = {42}();
   |             ^^^^--
   |             |
   |             call expression requires function
```
instead of
```
error[E0618]: expected function, found `_`
  --> $DIR/call-block.rs:2:13
   |
LL |     let _ = {42}();
   |             ^^^^--
   |             |
   |             call expression requires function
```

…-assoc-items, r=estebank

Suggest similarly named associated items in trait impls

Fix rust-lang#85942

Previously, the compiler didn't suggest similarly named associated items unlike we do in many situations. This patch adds such diagnostics for associated functions, types, and constants.

Add `#[must_not_suspend]` to some types in std

I am not sure what else should have it? `Ref`?

thread: implements available_concurrency on haiku

…ariant-match, r=davidtwco

fix(lint): don't suggest refutable patterns to "fix" irrefutable bind

In function arguments and let bindings, do not suggest changing `C` to `Foo::C` unless `C` is the only variant of `Foo`, because it won't work.

The general warning is still kept, because code like this is confusing.

Fixes rust-lang#88730

p.s. `src/test/ui/lint/lint-uppercase-variables.rs` already tests the one-variant case.

…li-obk

CTFE: tweak aggregate rvalue handling

I have not looked at this code in ages... I think Miri does not even hit it, since (most?) aggregate rvalues are lowered somewhere in the MIR pipeline, but CTFE does hit it.

So this adds some extra sanity assertions, and removes a ZST special case -- ZST should only be special cased fairly late (when the actual memory access happens); e.g. `!` is a ZST and we still want `copy_op` to be called for it since it will perform validation (and raise UB, since `!` is never valid).

bootstrap: Update comment in config.library.toml.

Downloading LLVM from CI works for all platforms now.

All other templates in this directory already have the proper comment. Seems this one was neglected.