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Check alias args for WF even if they have escaping bound vars by compiler-errors · Pull Request #123737 · rust-lang/rust

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Apr 10, 2024

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Apr 10, 2024 
Check alias args for WF even if they have escaping bound vars

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Apr 15, 2024 
Check alias args for WF even if they have escaping bound vars

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Jul 2, 2024

github-actions bot pushed a commit to rust-lang/miri that referenced this pull request

Jul 4, 2024 
Check alias args for WF even if they have escaping bound vars

#### What

This PR stops skipping arguments of aliases if they have escaping bound vars, instead recursing into them and only discarding the resulting obligations referencing bounds vars.

#### An example:

From the test:
```
trait Trait {
    type Gat<U: ?Sized>;
}

fn test<T>(f: for<'a> fn(<&'a T as Trait>::Gat<&'a [str]>)) where for<'a> &'a T: Trait {}
//~^ ERROR the size for values of type `[()]` cannot be known at compilation time

fn main() {}
```

We now prove that `str: Sized` in order for `&'a [str]` to be well-formed. We were previously unconditionally skipping over `&'a [str]` as it referenced a buond variable. We now recurse into it and instead only discard the `[str]: 'a` obligation because of the escaping bound vars.

#### Why?

This is a change that improves consistency about proving well-formedness earlier in the pipeline, which is necessary for future work on where-bounds in binders and correctly handling higher-ranked implied bounds. I don't expect this to fix any unsoundness.

#### What doesn't it fix?

Specifically, this doesn't check projection predicates' components are well-formed, because there are too many regressions: rust-lang/rust#123737 (comment)

lnicola pushed a commit to lnicola/rust-analyzer that referenced this pull request

Jul 11, 2024 
Check alias args for WF even if they have escaping bound vars

#### What

This PR stops skipping arguments of aliases if they have escaping bound vars, instead recursing into them and only discarding the resulting obligations referencing bounds vars.

#### An example:

From the test:
```
trait Trait {
    type Gat<U: ?Sized>;
}

fn test<T>(f: for<'a> fn(<&'a T as Trait>::Gat<&'a [str]>)) where for<'a> &'a T: Trait {}
//~^ ERROR the size for values of type `[()]` cannot be known at compilation time

fn main() {}
```

We now prove that `str: Sized` in order for `&'a [str]` to be well-formed. We were previously unconditionally skipping over `&'a [str]` as it referenced a buond variable. We now recurse into it and instead only discard the `[str]: 'a` obligation because of the escaping bound vars.

#### Why?

This is a change that improves consistency about proving well-formedness earlier in the pipeline, which is necessary for future work on where-bounds in binders and correctly handling higher-ranked implied bounds. I don't expect this to fix any unsoundness.

#### What doesn't it fix?

Specifically, this doesn't check projection predicates' components are well-formed, because there are too many regressions: rust-lang/rust#123737 (comment)

tmeijn pushed a commit to tmeijn/dotfiles that referenced this pull request

Sep 11, 2024 
This MR contains the following updates:

| Package | Update | Change |
|---|---|---|
| [rust](https://github.com/rust-lang/rust) | minor | `1.80.1` -> `1.81.0` |

MR created with the help of [el-capitano/tools/renovate-bot](https://gitlab.com/el-capitano/tools/renovate-bot).

**Proposed changes to behavior should be submitted there as MRs.**

---

### Release Notes

<details>
<summary>rust-lang/rust (rust)</summary>

### [`v1.81.0`](https://github.com/rust-lang/rust/blob/HEAD/RELEASES.md#Version-1810-2024-09-05)

[Compare Source](rust-lang/rust@1.80.1...1.81.0)

\==========================

<a id="1.81.0-Language"></a>

## Language

-   [Abort on uncaught panics in `extern "C"` functions.](rust-lang/rust#116088)
-   [Fix ambiguous cases of multiple `&` in elided self lifetimes.](rust-lang/rust#117967)
-   [Stabilize `#[expect]` for lints (RFC 2383),](rust-lang/rust#120924) like `#[allow]` with a warning if the lint is *not* fulfilled.
-   [Change method resolution to constrain hidden types instead of rejecting method candidates.](rust-lang/rust#123962)
-   [Bump `elided_lifetimes_in_associated_constant` to deny.](rust-lang/rust#124211)
-   [`offset_from`: always allow pointers to point to the same address.](rust-lang/rust#124921)
-   [Allow constraining opaque types during subtyping in the trait system.](rust-lang/rust#125447)
-   [Allow constraining opaque types during various unsizing casts.](rust-lang/rust#125610)
-   [Deny keyword lifetimes pre-expansion.](rust-lang/rust#126762)

<a id="1.81.0-Compiler"></a>

## Compiler

-   [Make casts of pointers to trait objects stricter.](rust-lang/rust#120248)
-   [Check alias args for well-formedness even if they have escaping bound vars.](rust-lang/rust#123737)
-   [Deprecate no-op codegen option `-Cinline-threshold=...`.](rust-lang/rust#124712)
-   [Re-implement a type-size based limit.](rust-lang/rust#125507)
-   [Properly account for alignment in `transmute` size checks.](rust-lang/rust#125740)
-   [Remove the `box_pointers` lint.](rust-lang/rust#126018)
-   [Ensure the interpreter checks bool/char for validity when they are used in a cast.](rust-lang/rust#126265)
-   [Improve coverage instrumentation for functions containing nested items.](rust-lang/rust#127199)
-   Target changes:
    -   [Add Tier 3 `no_std` Xtensa targets:](rust-lang/rust#125141) `xtensa-esp32-none-elf`, `xtensa-esp32s2-none-elf`, `xtensa-esp32s3-none-elf`
    -   [Add Tier 3 `std` Xtensa targets:](rust-lang/rust#126380) `xtensa-esp32-espidf`, `xtensa-esp32s2-espidf`, `xtensa-esp32s3-espidf`
    -   [Add Tier 3 i686 Redox OS target:](rust-lang/rust#126192) `i686-unknown-redox`
    -   [Promote `arm64ec-pc-windows-msvc` to Tier 2.](rust-lang/rust#126039)
    -   [Promote `loongarch64-unknown-linux-musl` to Tier 2 with host tools.](rust-lang/rust#126298)
    -   [Enable full tools and profiler for LoongArch Linux targets.](rust-lang/rust#127078)
    -   [Unconditionally warn on usage of `wasm32-wasi`.](rust-lang/rust#126662) (see compatibility note below)
    -   Refer to Rust's \[platform support page]\[platform-support-doc] for more information on Rust's tiered platform support.

<a id="1.81.0-Libraries"></a>

## Libraries

-   [Split core's `PanicInfo` and std's `PanicInfo`.](rust-lang/rust#115974) (see compatibility note below)
-   [Generalize `{Rc,Arc}::make_mut()` to unsized types.](rust-lang/rust#116113)
-   [Replace sort implementations with stable `driftsort` and unstable `ipnsort`.](rust-lang/rust#124032) All `slice::sort*` and `slice::select_nth*` methods are expected to see significant performance improvements. See the [research project](https://github.com/Voultapher/sort-research-rs) for more details.
-   [Document behavior of `create_dir_all` with respect to empty paths.](rust-lang/rust#125112)
-   [Fix interleaved output in the default panic hook when multiple threads panic simultaneously.](rust-lang/rust#127397)

<a id="1.81.0-Stabilized-APIs"></a>

## Stabilized APIs

-   [`core::error`](https://doc.rust-lang.org/stable/core/error/index.html)
-   [`hint::assert_unchecked`](https://doc.rust-lang.org/stable/core/hint/fn.assert_unchecked.html)
-   [`fs::exists`](https://doc.rust-lang.org/stable/std/fs/fn.exists.html)
-   [`AtomicBool::fetch_not`](https://doc.rust-lang.org/stable/core/sync/atomic/struct.AtomicBool.html#method.fetch_not)
-   [`Duration::abs_diff`](https://doc.rust-lang.org/stable/core/time/struct.Duration.html#method.abs_diff)
-   [`IoSlice::advance`](https://doc.rust-lang.org/stable/std/io/struct.IoSlice.html#method.advance)
-   [`IoSlice::advance_slices`](https://doc.rust-lang.org/stable/std/io/struct.IoSlice.html#method.advance_slices)
-   [`IoSliceMut::advance`](https://doc.rust-lang.org/stable/std/io/struct.IoSliceMut.html#method.advance)
-   [`IoSliceMut::advance_slices`](https://doc.rust-lang.org/stable/std/io/struct.IoSliceMut.html#method.advance_slices)
-   [`PanicHookInfo`](https://doc.rust-lang.org/stable/std/panic/struct.PanicHookInfo.html)
-   [`PanicInfo::message`](https://doc.rust-lang.org/stable/core/panic/struct.PanicInfo.html#method.message)
-   [`PanicMessage`](https://doc.rust-lang.org/stable/core/panic/struct.PanicMessage.html)

These APIs are now stable in const contexts:

-   [`char::from_u32_unchecked`](https://doc.rust-lang.org/stable/core/char/fn.from_u32\_unchecked.html) (function)
-   [`char::from_u32_unchecked`](https://doc.rust-lang.org/stable/core/primitive.char.html#method.from_u32\_unchecked) (method)
-   [`CStr::count_bytes`](https://doc.rust-lang.org/stable/core/ffi/c_str/struct.CStr.html#method.count_bytes)
-   [`CStr::from_ptr`](https://doc.rust-lang.org/stable/core/ffi/c_str/struct.CStr.html#method.from_ptr)

<a id="1.81.0-Cargo"></a>

## Cargo

-   [Generated `.cargo_vcs_info.json` is always included, even when `--allow-dirty` is passed.](rust-lang/cargo#13960)
-   [Disallow `package.license-file` and `package.readme` pointing to non-existent files during packaging.](rust-lang/cargo#13921)
-   [Disallow passing `--release`/`--debug` flag along with the `--profile` flag.](rust-lang/cargo#13971)
-   [Remove `lib.plugin` key support in `Cargo.toml`. Rust plugin support has been deprecated for four years and was removed in 1.75.0.](rust-lang/cargo#13902)

<a id="1.81.0-Compatibility-Notes"></a>

## Compatibility Notes

-   Usage of the `wasm32-wasi` target will now issue a compiler warning and request users switch to the `wasm32-wasip1` target instead. Both targets are the same, `wasm32-wasi` is only being renamed, and this [change to the WASI target](https://blog.rust-lang.org/2024/04/09/updates-to-rusts-wasi-targets.html) is being done to enable removing `wasm32-wasi` in January 2025.

-   We have renamed `std::panic::PanicInfo` to `std::panic::PanicHookInfo`. The old name will continue to work as an alias, but will result in a deprecation warning starting in Rust 1.82.0.

    `core::panic::PanicInfo` will remain unchanged, however, as this is now a *different type*.

    The reason is that these types have different roles: `std::panic::PanicHookInfo` is the argument to the [panic hook](https://doc.rust-lang.org/stable/std/panic/fn.set_hook.html) in std context (where panics can have an arbitrary payload), while `core::panic::PanicInfo` is the argument to the [`#[panic_handler]`](https://doc.rust-lang.org/nomicon/panic-handler.html) in no_std context (where panics always carry a formatted *message*). Separating these types allows us to add more useful methods to these types, such as `std::panic::PanicHookInfo::payload_as_str()` and `core::panic::PanicInfo::message()`.

-   The new sort implementations may panic if a type's implementation of [`Ord`](https://doc.rust-lang.org/std/cmp/trait.Ord.html) (or the given comparison function) does not implement a [total order](https://en.wikipedia.org/wiki/Total_order) as the trait requires. `Ord`'s supertraits (`PartialOrd`, `Eq`, and `PartialEq`) must also be consistent. The previous implementations would not "notice" any problem, but the new implementations have a good chance of detecting inconsistencies, throwing a panic rather than returning knowingly unsorted data.

-   [In very rare cases, a change in the internal evaluation order of the trait
    solver may result in new fatal overflow errors.](rust-lang/rust#126128)

<a id="1.81.0-Internal-Changes"></a>

## Internal Changes

These changes do not affect any public interfaces of Rust, but they represent
significant improvements to the performance or internals of rustc and related
tools.

-   [Add a Rust-for Linux `auto` CI job to check kernel builds.](rust-lang/rust#125209)

</details>

---

### Configuration

📅 **Schedule**: Branch creation - At any time (no schedule defined), Automerge - At any time (no schedule defined).

🚦 **Automerge**: Disabled by config. Please merge this manually once you are satisfied.

♻ **Rebasing**: Whenever MR becomes conflicted, or you tick the rebase/retry checkbox.

🔕 **Ignore**: Close this MR and you won't be reminded about this update again.

---

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---

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wip-sync pushed a commit to NetBSD/pkgsrc-wip that referenced this pull request

Sep 22, 2024 
Pkgsrc changes:
 * Adapt patches, apply to new vendored crates where needed.
 * Back-port rust pull request 130110, "make dist vendoring configurable"
 * Disable "dist vendoring", otherwise cargo would try to access
   the network during the build phase.

Upstream changes:

Version 1.81.0 (2024-09-05)
==========================

Language
--------

- [Abort on uncaught panics in `extern "C"` functions.]
  (rust-lang/rust#116088)
- [Fix ambiguous cases of multiple `&` in elided self lifetimes.]
  (rust-lang/rust#117967)
- [Stabilize `#[expect]` for lints (RFC 2383),]
  (rust-lang/rust#120924) like `#[allow]`
  with a warning if the lint is _not_ fulfilled.
- [Change method resolution to constrain hidden types instead of
  rejecting method candidates.]
  (rust-lang/rust#123962)
- [Bump `elided_lifetimes_in_associated_constant` to deny.]
  (rust-lang/rust#124211)
- [`offset_from`: always allow pointers to point to the same
  address.] (rust-lang/rust#124921)
- [Allow constraining opaque types during subtyping in the trait
  system.] (rust-lang/rust#125447)
- [Allow constraining opaque types during various unsizing casts.]
  (rust-lang/rust#125610)
- [Deny keyword lifetimes pre-expansion.]
  (rust-lang/rust#126762)

Compiler
--------

- [Make casts of pointers to trait objects stricter.]
  (rust-lang/rust#120248)
- [Check alias args for well-formedness even if they have escaping
  bound vars.] (rust-lang/rust#123737)
- [Deprecate no-op codegen option `-Cinline-threshold=...`.]
  (rust-lang/rust#124712)
- [Re-implement a type-size based limit.]
  (rust-lang/rust#125507)
- [Properly account for alignment in `transmute` size checks.]
  (rust-lang/rust#125740)
- [Remove the `box_pointers` lint.]
  (rust-lang/rust#126018)
- [Ensure the interpreter checks bool/char for validity when they
  are used in a cast.] (rust-lang/rust#126265)
- [Improve coverage instrumentation for functions containing nested
  items.] (rust-lang/rust#127199)
- Target changes:
  - [Add Tier 3 `no_std` Xtensa targets:]
    (rust-lang/rust#125141) `xtensa-esp32-none-elf`,
    `xtensa-esp32s2-none-elf`, `xtensa-esp32s3-none-elf`
  - [Add Tier 3 `std` Xtensa targets:]
    (rust-lang/rust#126380) `xtensa-esp32-espidf`,
    `xtensa-esp32s2-espidf`, `xtensa-esp32s3-espidf`
  - [Add Tier 3 i686 Redox OS target:]
    (rust-lang/rust#126192) `i686-unknown-redox`
  - [Promote `arm64ec-pc-windows-msvc` to Tier 2.]
    (rust-lang/rust#126039)
  - [Promote `wasm32-wasip2` to Tier 2.]
    (rust-lang/rust#126967)
  - [Promote `loongarch64-unknown-linux-musl` to Tier 2 with host
    tools.] (rust-lang/rust#126298)
  - [Enable full tools and profiler for LoongArch Linux targets.]
    (rust-lang/rust#127078)
  - [Unconditionally warn on usage of `wasm32-wasi`.]
    (rust-lang/rust#126662) (see compatibility
    note below)
  - Refer to Rust's [platform support page][platform-support-doc]
    for more information on Rust's tiered platform support.

Libraries
---------

- [Split core's `PanicInfo` and std's `PanicInfo`.]
  (rust-lang/rust#115974) (see compatibility
  note below)
- [Generalize `{Rc,Arc}::make_mut()` to unsized types.]
  (rust-lang/rust#116113)
- [Replace sort implementations with stable `driftsort` and unstable
  `ipnsort`.] (rust-lang/rust#124032) All
  `slice::sort*` and `slice::select_nth*` methods are expected to
  see significant performance improvements. See the [research
  project] (https://github.com/Voultapher/sort-research-rs) for
  more details.
- [Document behavior of `create_dir_all` with respect to empty
  paths.] (rust-lang/rust#125112)
- [Fix interleaved output in the default panic hook when multiple
  threads panic simultaneously.]
  (rust-lang/rust#127397)
- Fix `Command`'s batch files argument escaping not working when
  file name has trailing whitespace or periods (CVE-2024-43402).

Stabilized APIs
---------------

- [`core::error`] (https://doc.rust-lang.org/stable/core/error/index.html)
- [`hint::assert_unchecked`]
  (https://doc.rust-lang.org/stable/core/hint/fn.assert_unchecked.html)
- [`fs::exists`] (https://doc.rust-lang.org/stable/std/fs/fn.exists.html)
- [`AtomicBool::fetch_not`]
  (https://doc.rust-lang.org/stable/core/sync/atomic/struct.AtomicBool.html#method.fetch_not)
- [`Duration::abs_diff`]
  (https://doc.rust-lang.org/stable/core/time/struct.Duration.html#method.abs_diff)
- [`IoSlice::advance`]
  (https://doc.rust-lang.org/stable/std/io/struct.IoSlice.html#method.advance)
- [`IoSlice::advance_slices`]
  (https://doc.rust-lang.org/stable/std/io/struct.IoSlice.html#method.advance_slices)
- [`IoSliceMut::advance`]
  (https://doc.rust-lang.org/stable/std/io/struct.IoSliceMut.html#method.advance)
- [`IoSliceMut::advance_slices`]
  (https://doc.rust-lang.org/stable/std/io/struct.IoSliceMut.html#method.advance_slices)
- [`PanicHookInfo`]
  (https://doc.rust-lang.org/stable/std/panic/struct.PanicHookInfo.html)
- [`PanicInfo::message`]
  (https://doc.rust-lang.org/stable/core/panic/struct.PanicInfo.html#method.message)
- [`PanicMessage`]
  (https://doc.rust-lang.org/stable/core/panic/struct.PanicMessage.html)

These APIs are now stable in const contexts:

- [`char::from_u32_unchecked`]
  (https://doc.rust-lang.org/stable/core/char/fn.from_u32_unchecked.html)
  (function)
- [`char::from_u32_unchecked`]
  (https://doc.rust-lang.org/stable/core/primitive.char.html#method.from_u32_unchecked)
  (method)
- [`CStr::count_bytes`]
  (https://doc.rust-lang.org/stable/core/ffi/c_str/struct.CStr.html#method.count_bytes)
- [`CStr::from_ptr`]
  (https://doc.rust-lang.org/stable/core/ffi/c_str/struct.CStr.html#method.from_ptr)

Cargo
-----

- [Generated `.cargo_vcs_info.json` is always included, even when
  `--allow-dirty` is passed.]
  (rust-lang/cargo#13960)
- [Disallow `package.license-file` and `package.readme` pointing
  to non-existent files during packaging.]
  (rust-lang/cargo#13921)
- [Disallow passing `--release`/`--debug` flag along with the
  `--profile` flag.] (rust-lang/cargo#13971)
- [Remove `lib.plugin` key support in `Cargo.toml`. Rust plugin
  support has been deprecated for four years and was removed in
  1.75.0.] (rust-lang/cargo#13902)

Compatibility Notes
-------------------

* Usage of the `wasm32-wasi` target will now issue a compiler
  warning and request users switch to the `wasm32-wasip1` target
  instead. Both targets are the same, `wasm32-wasi` is only being
  renamed, and this [change to the WASI target]
  (https://blog.rust-lang.org/2024/04/09/updates-to-rusts-wasi-targets.html)
  is being done to enable removing `wasm32-wasi` in January 2025.

* We have renamed `std::panic::PanicInfo` to `std::panic::PanicHookInfo`.
  The old name will continue to work as an alias, but will result in
  a deprecation warning starting in Rust 1.82.0.

  `core::panic::PanicInfo` will remain unchanged, however, as this
  is now a *different type*.

  The reason is that these types have different roles:
  `std::panic::PanicHookInfo` is the argument to the [panic
  hook](https://doc.rust-lang.org/stable/std/panic/fn.set_hook.html)
  in std context (where panics can have an arbitrary payload),
  while `core::panic::PanicInfo` is the argument to the
  [`#[panic_handler]`](https://doc.rust-lang.org/nomicon/panic-handler.html)
  in no_std context (where panics always carry a formatted *message*).
  Separating these types allows us to add more useful methods to
  these types, such as `std::panic::PanicHookInfo::payload_as_str()`
  and `core::panic::PanicInfo::message()`.

* The new sort implementations may panic if a type's implementation
  of [`Ord`](https://doc.rust-lang.org/std/cmp/trait.Ord.html) (or
  the given comparison function) does not implement a [total
  order](https://en.wikipedia.org/wiki/Total_order) as the trait
  requires. `Ord`'s supertraits (`PartialOrd`, `Eq`, and `PartialEq`)
  must also be consistent. The previous implementations would not
  "notice" any problem, but the new implementations have a good chance
  of detecting inconsistencies, throwing a panic rather than returning
  knowingly unsorted data.
* [In very rare cases, a change in the internal evaluation order of the trait
  solver may result in new fatal overflow errors.]
  (rust-lang/rust#126128)

Internal Changes
----------------

These changes do not affect any public interfaces of Rust, but they
represent significant improvements to the performance or internals
of rustc and related tools.

- [Add a Rust-for Linux `auto` CI job to check kernel builds.]
  (rust-lang/rust#125209)

netbsd-srcmastr pushed a commit to NetBSD/pkgsrc that referenced this pull request

Nov 24, 2024 
Pkgsrc changes:
 * Adapt patches, apply to new vendored crates where needed.
 * Back-port rust pull request 130110, "make dist vendoring configurable"
 * Disable "dist vendoring", otherwise cargo would try to access
   the network during the build phase.

Upstream changes:

Version 1.81.0 (2024-09-05)
==========================

Language
--------

- [Abort on uncaught panics in `extern "C"` functions.]
  (rust-lang/rust#116088)
- [Fix ambiguous cases of multiple `&` in elided self lifetimes.]
  (rust-lang/rust#117967)
- [Stabilize `#[expect]` for lints (RFC 2383),]
  (rust-lang/rust#120924) like `#[allow]`
  with a warning if the lint is _not_ fulfilled.
- [Change method resolution to constrain hidden types instead of
  rejecting method candidates.]
  (rust-lang/rust#123962)
- [Bump `elided_lifetimes_in_associated_constant` to deny.]
  (rust-lang/rust#124211)
- [`offset_from`: always allow pointers to point to the same
  address.] (rust-lang/rust#124921)
- [Allow constraining opaque types during subtyping in the trait
  system.] (rust-lang/rust#125447)
- [Allow constraining opaque types during various unsizing casts.]
  (rust-lang/rust#125610)
- [Deny keyword lifetimes pre-expansion.]
  (rust-lang/rust#126762)

Compiler
--------

- [Make casts of pointers to trait objects stricter.]
  (rust-lang/rust#120248)
- [Check alias args for well-formedness even if they have escaping
  bound vars.] (rust-lang/rust#123737)
- [Deprecate no-op codegen option `-Cinline-threshold=...`.]
  (rust-lang/rust#124712)
- [Re-implement a type-size based limit.]
  (rust-lang/rust#125507)
- [Properly account for alignment in `transmute` size checks.]
  (rust-lang/rust#125740)
- [Remove the `box_pointers` lint.]
  (rust-lang/rust#126018)
- [Ensure the interpreter checks bool/char for validity when they
  are used in a cast.] (rust-lang/rust#126265)
- [Improve coverage instrumentation for functions containing nested
  items.] (rust-lang/rust#127199)
- Target changes:
  - [Add Tier 3 `no_std` Xtensa targets:]
    (rust-lang/rust#125141) `xtensa-esp32-none-elf`,
    `xtensa-esp32s2-none-elf`, `xtensa-esp32s3-none-elf`
  - [Add Tier 3 `std` Xtensa targets:]
    (rust-lang/rust#126380) `xtensa-esp32-espidf`,
    `xtensa-esp32s2-espidf`, `xtensa-esp32s3-espidf`
  - [Add Tier 3 i686 Redox OS target:]
    (rust-lang/rust#126192) `i686-unknown-redox`
  - [Promote `arm64ec-pc-windows-msvc` to Tier 2.]
    (rust-lang/rust#126039)
  - [Promote `wasm32-wasip2` to Tier 2.]
    (rust-lang/rust#126967)
  - [Promote `loongarch64-unknown-linux-musl` to Tier 2 with host
    tools.] (rust-lang/rust#126298)
  - [Enable full tools and profiler for LoongArch Linux targets.]
    (rust-lang/rust#127078)
  - [Unconditionally warn on usage of `wasm32-wasi`.]
    (rust-lang/rust#126662) (see compatibility
    note below)
  - Refer to Rust's [platform support page][platform-support-doc]
    for more information on Rust's tiered platform support.

Libraries
---------

- [Split core's `PanicInfo` and std's `PanicInfo`.]
  (rust-lang/rust#115974) (see compatibility
  note below)
- [Generalize `{Rc,Arc}::make_mut()` to unsized types.]
  (rust-lang/rust#116113)
- [Replace sort implementations with stable `driftsort` and unstable
  `ipnsort`.] (rust-lang/rust#124032) All
  `slice::sort*` and `slice::select_nth*` methods are expected to
  see significant performance improvements. See the [research
  project] (https://github.com/Voultapher/sort-research-rs) for
  more details.
- [Document behavior of `create_dir_all` with respect to empty
  paths.] (rust-lang/rust#125112)
- [Fix interleaved output in the default panic hook when multiple
  threads panic simultaneously.]
  (rust-lang/rust#127397)
- Fix `Command`'s batch files argument escaping not working when
  file name has trailing whitespace or periods (CVE-2024-43402).

Stabilized APIs
---------------

- [`core::error`] (https://doc.rust-lang.org/stable/core/error/index.html)
- [`hint::assert_unchecked`]
  (https://doc.rust-lang.org/stable/core/hint/fn.assert_unchecked.html)
- [`fs::exists`] (https://doc.rust-lang.org/stable/std/fs/fn.exists.html)
- [`AtomicBool::fetch_not`]
  (https://doc.rust-lang.org/stable/core/sync/atomic/struct.AtomicBool.html#method.fetch_not)
- [`Duration::abs_diff`]
  (https://doc.rust-lang.org/stable/core/time/struct.Duration.html#method.abs_diff)
- [`IoSlice::advance`]
  (https://doc.rust-lang.org/stable/std/io/struct.IoSlice.html#method.advance)
- [`IoSlice::advance_slices`]
  (https://doc.rust-lang.org/stable/std/io/struct.IoSlice.html#method.advance_slices)
- [`IoSliceMut::advance`]
  (https://doc.rust-lang.org/stable/std/io/struct.IoSliceMut.html#method.advance)
- [`IoSliceMut::advance_slices`]
  (https://doc.rust-lang.org/stable/std/io/struct.IoSliceMut.html#method.advance_slices)
- [`PanicHookInfo`]
  (https://doc.rust-lang.org/stable/std/panic/struct.PanicHookInfo.html)
- [`PanicInfo::message`]
  (https://doc.rust-lang.org/stable/core/panic/struct.PanicInfo.html#method.message)
- [`PanicMessage`]
  (https://doc.rust-lang.org/stable/core/panic/struct.PanicMessage.html)

These APIs are now stable in const contexts:

- [`char::from_u32_unchecked`]
  (https://doc.rust-lang.org/stable/core/char/fn.from_u32_unchecked.html)
  (function)
- [`char::from_u32_unchecked`]
  (https://doc.rust-lang.org/stable/core/primitive.char.html#method.from_u32_unchecked)
  (method)
- [`CStr::count_bytes`]
  (https://doc.rust-lang.org/stable/core/ffi/c_str/struct.CStr.html#method.count_bytes)
- [`CStr::from_ptr`]
  (https://doc.rust-lang.org/stable/core/ffi/c_str/struct.CStr.html#method.from_ptr)

Cargo
-----

- [Generated `.cargo_vcs_info.json` is always included, even when
  `--allow-dirty` is passed.]
  (rust-lang/cargo#13960)
- [Disallow `package.license-file` and `package.readme` pointing
  to non-existent files during packaging.]
  (rust-lang/cargo#13921)
- [Disallow passing `--release`/`--debug` flag along with the
  `--profile` flag.] (rust-lang/cargo#13971)
- [Remove `lib.plugin` key support in `Cargo.toml`. Rust plugin
  support has been deprecated for four years and was removed in
  1.75.0.] (rust-lang/cargo#13902)

Compatibility Notes
-------------------

* Usage of the `wasm32-wasi` target will now issue a compiler
  warning and request users switch to the `wasm32-wasip1` target
  instead. Both targets are the same, `wasm32-wasi` is only being
  renamed, and this [change to the WASI target]
  (https://blog.rust-lang.org/2024/04/09/updates-to-rusts-wasi-targets.html)
  is being done to enable removing `wasm32-wasi` in January 2025.

* We have renamed `std::panic::PanicInfo` to `std::panic::PanicHookInfo`.
  The old name will continue to work as an alias, but will result in
  a deprecation warning starting in Rust 1.82.0.

  `core::panic::PanicInfo` will remain unchanged, however, as this
  is now a *different type*.

  The reason is that these types have different roles:
  `std::panic::PanicHookInfo` is the argument to the [panic
  hook](https://doc.rust-lang.org/stable/std/panic/fn.set_hook.html)
  in std context (where panics can have an arbitrary payload),
  while `core::panic::PanicInfo` is the argument to the
  [`#[panic_handler]`](https://doc.rust-lang.org/nomicon/panic-handler.html)
  in no_std context (where panics always carry a formatted *message*).
  Separating these types allows us to add more useful methods to
  these types, such as `std::panic::PanicHookInfo::payload_as_str()`
  and `core::panic::PanicInfo::message()`.

* The new sort implementations may panic if a type's implementation
  of [`Ord`](https://doc.rust-lang.org/std/cmp/trait.Ord.html) (or
  the given comparison function) does not implement a [total
  order](https://en.wikipedia.org/wiki/Total_order) as the trait
  requires. `Ord`'s supertraits (`PartialOrd`, `Eq`, and `PartialEq`)
  must also be consistent. The previous implementations would not
  "notice" any problem, but the new implementations have a good chance
  of detecting inconsistencies, throwing a panic rather than returning
  knowingly unsorted data.
* [In very rare cases, a change in the internal evaluation order of the trait
  solver may result in new fatal overflow errors.]
  (rust-lang/rust#126128)

Internal Changes
----------------

These changes do not affect any public interfaces of Rust, but they
represent significant improvements to the performance or internals
of rustc and related tools.

- [Add a Rust-for Linux `auto` CI job to check kernel builds.]
  (rust-lang/rust#125209)

Kobzol pushed a commit to Kobzol/portable-simd that referenced this pull request

Feb 3, 2026 
Check alias args for WF even if they have escaping bound vars

#### What

This PR stops skipping arguments of aliases if they have escaping bound vars, instead recursing into them and only discarding the resulting obligations referencing bounds vars.

#### An example:

From the test:
```
trait Trait {
    type Gat<U: ?Sized>;
}

fn test<T>(f: for<'a> fn(<&'a T as Trait>::Gat<&'a [str]>)) where for<'a> &'a T: Trait {}
//~^ ERROR the size for values of type `[()]` cannot be known at compilation time

fn main() {}
```

We now prove that `str: Sized` in order for `&'a [str]` to be well-formed. We were previously unconditionally skipping over `&'a [str]` as it referenced a buond variable. We now recurse into it and instead only discard the `[str]: 'a` obligation because of the escaping bound vars.

#### Why?

This is a change that improves consistency about proving well-formedness earlier in the pipeline, which is necessary for future work on where-bounds in binders and correctly handling higher-ranked implied bounds. I don't expect this to fix any unsoundness.

#### What doesn't it fix?

Specifically, this doesn't check projection predicates' components are well-formed, because there are too many regressions: rust-lang/rust#123737 (comment)