…types

… framing

…casts.

ALL

OF

THEM

… test it

* split `fuzzy_provenance_casts` into a ptr2int and a int2ptr lint
* feature gate both lints
* update documentation to be more realistic short term
* add tests for these lints

Relevant commit messages from squashed history in order:

Add initial version of ThinBox

update test to actually capture failure

swap to middle ptr impl based on matthieu-m's design

Fix stack overflow in debug impl

The previous version would take a `&ThinBox<T>` and deref it once, which
resulted in a no-op and the same type, which it would then print causing
an endless recursion. I've switched to calling `deref` by name to let
method resolution handle deref the correct number of times.

I've also updated the Drop impl for good measure since it seemed like it
could be falling prey to the same bug, and I'll be adding some tests to
verify that the drop is happening correctly.

add test to verify drop is behaving

add doc examples and remove unnecessary Pointee bounds

ThinBox: use NonNull

ThinBox: tests for size

Apply suggestions from code review

Co-authored-by: Alphyr <[email protected]>

use handle_alloc_error and fix drop signature

update niche and size tests

add cfg for allocating APIs

check null before calculating offset

add test for zst and trial usage

prevent optimizer induced ub in drop and cleanup metadata gathering

account for arbitrary size and alignment metadata

Thank you nika and thomcc!

Update library/alloc/src/boxed/thin.rs

Co-authored-by: Josh Triplett <[email protected]>

Update library/alloc/src/boxed/thin.rs

Co-authored-by: Josh Triplett <[email protected]>

They were introduced by the final commit in rust-lang#95159 and gave a
performance win. But since the introduction of `MatcherLoc` they are no
longer needed. This commit reverts that change, making the code a bit
simpler.

Add new ThinBox type for 1 stack pointer wide heap allocated trait objects

**Zulip Thread**: https://rust-lang.zulipchat.com/#narrow/stream/219381-t-libs/topic/ThinBox

Based on https://github.com/matthieu-m/rfc2580/blob/b58d1d3cba0d4b5e859d3617ea2d0943aaa31329/examples/thin.rs

Tracking Issue: rust-lang#92791

Usage Trial: https://github.com/yaahc/pgx/pull/1/files

## TODO

- [x] make sure to test with #[repr(align(1024))] structs etc

…k-Simulacrum

assert_uninit_valid: ensure we detect at least arrays of uninhabited types

We can't easily extend this check to *all* arrays (Cc rust-lang#87041), but it turns out the existing check already catches arrays of uninhabited types. So let's make sure it stays that way by adding them to the test.

…chaelwoerister

Strict provenance lints

See rust-lang#95488.
This PR introduces two unstable (allow by default) lints to which lint on int2ptr and ptr2int casts, as the former is not possible in the strict provenance model and the latter can be written nicer using the `.addr()` API.
Based on an initial version of the lint by ```@Gankra``` in rust-lang#95199.

Don't report numeric inference ambiguity when we have previous errors

Fixes rust-lang#95648

[macro_metavar_expr] Add tests to ensure the feature requirement

These tests should have been added in the initial implementation they were unintentionally forgotten

cc rust-lang#83527
r? ````@petrochenkov````

reword panic vs result section to remove recoverable vs unrecoverable framing

Based on feedback from the Error Handling FAQ: rust-lang/project-error-handling#50 (comment)

r? ````@dtolnay````

…=petrochenkov

Remove explicit delimiter token trees from `Delimited`.

They were introduced by the final commit in rust-lang#95159 and gave a
performance win. But since the introduction of `MatcherLoc` they are no
longer needed. This commit reverts that change, making the code a bit
simpler.

r? `@petrochenkov`

…th-backline, r=notriddle

rustdoc: Fix empty doc comment with backline ICE

Fixes rust-lang#95800.

r? ```@notriddle```