Co-authored-by: Jakub Beránek <berykubik@gmail.com>

Co-authored-by: Jakub Beránek <berykubik@gmail.com>

CC rust-lang#89566.

ZeroSized constants can be represented as `mir::Const::Val` even if
their layout is not yet known. In those cases, CrateItem::body() was
crashing when trying to convert a `ConstValue::ZeroSized` into its
stable counterpart `ConstantKind::Allocated`.

Instead, we now map `ConstValue::ZeroSized` into a new variant:
`ConstantKind::ZeroSized`.

…-to-docs, r=ehuss

feat(docs): add cargo-pgo to PGO documentation 📝

fixes rust-lang#114995

Tweak suggestion span for outer attr and point at item following invalid inner attr

After:

```
error: `unix_sigpipe` attribute cannot be used at crate level
  --> $DIR/unix_sigpipe-crate.rs:2:1
   |
LL | #![unix_sigpipe = "inherit"]
   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
LL |
LL | fn main() {}
   | ------------ the inner attribute doesn't annotate this function
   |
help: perhaps you meant to use an outer attribute
   |
LL - #![unix_sigpipe = "inherit"]
LL + #[unix_sigpipe = "inherit"]
   |
```

Before:

```
error: `unix_sigpipe` attribute cannot be used at crate level
  --> $DIR/unix_sigpipe-crate.rs:2:1
   |
LL | #![unix_sigpipe = "inherit"]
   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
help: perhaps you meant to use an outer attribute
   |
LL | #[unix_sigpipe = "inherit"]
   | ~~~~~~~~~~~~~~~~~~~~~~~~~~~
```

CC rust-lang#89566.

…llect-into-fix-typo, r=the8472

Fix documentation typo in std::iter::Iterator::collect_into

…cle, r=oli-obk

Stash and cancel cycle errors for auto trait leakage in opaques

We don't need to emit a traditional cycle error when we have a selection error that explains what's going on but in more detail.

We may want to augment this error to actually point out the cycle, now that the cycle error is not being emitted. We could do that by storing the set of opaques that was in the `CyclePlaceholder` that gets returned from `type_of_opaque`.

r? `@oli-obk` cc `@estebank` rust-lang#117235

Create a new ConstantKind variant (ZeroSized) for StableMIR

ZeroSized constants can be represented as `mir::Const::Val` even if their layout is not yet known. In those cases, CrateItem::body() was crashing when trying to convert a `ConstValue::ZeroSized` into its stable counterpart  `ConstantKind::Allocated`.

Instead, we now map `ConstValue::ZeroSized` into a new variant: `ConstantKind::ZeroSized`.

**Note:** I didn't add any new test here since we already have covering tests in our project repository which I manually confirmed that will fix the issue.

replace transmute by raw pointer cast

Now that rust-lang#113257 is fixed we can finally do this. :)