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Point at source of trait bound obligations in more places #89580

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merged 11 commits into from
Nov 21, 2021

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estebank
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@estebank estebank commented Oct 5, 2021

Be more thorough in using ItemObligation and BindingObligation when
evaluating obligations so that we can point at trait bounds that
introduced unfulfilled obligations. We no longer incorrectly point at
unrelated trait bounds (substs-ppaux.verbose.stderr).

In particular, we now point at trait bounds on method calls.

We no longer point at "obvious" obligation sources (we no longer have a
note pointing at Trait saying "required by a bound in Trait", like
in associated-types-no-suitable-supertrait*).

We no longer point at associated items (ImplObligation), as they didn't
add any user actionable information, they just added noise.

Address part of #89418.

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r? @nagisa

(rust-highfive has picked a reviewer for you, use r? to override)

@rust-highfive rust-highfive added the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label Oct 5, 2021
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estebank commented Oct 5, 2021

I wonder if the error is because predicates_of now returns a DUMMY_SP for the trait's obligation. That would only affect this test if the span is the only thing being tracked in incremental, which would be a bug, right?

Edit: We can land this with extra verbosity pointing at traits, I can change the test to ignore predicates_of or I can rework the entire approach to try and signal that an obligation is coming from a trait in some other out of band way, instead of with DUMMY_SP (which arguably is the right thing to do, we just don't carry that kind of metadata today to tie the predicate to the ObligationCauseCode).

@cjgillot, I see that you touched this file. Do you know if there's any reliance on predicates_of changing when trait modifiers like pub and unsafe are changed? Currently they do because the change of the span, but with this PR's change, that's no longer true. Would it be reasonable to change the test to no longer look for that?

Another option would be to add an empty predicate type that represents pub and unsafe as a safeguard, but we likely don't want/need that.

Edit 2: I was halfway through atttempting the "signal origin in PredicateKind" approach when remembered that naïvely extending PredicateKind will cause fingerprinting issues, as I already tried to do something similar some time back and had to back off.

let span = match generics {
// This is to get around the trait identity obligation, that has a `DUMMY_SP` as signal
// for other diagnostics, so we need to recover it here.
Some((_, _, node)) if span.is_dummy() => node,
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Should this test be performed around the hir.span(hir_id) call?

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I thought about it, but because it is in a nested match doing that would have meant making span mutable and reassign to it in that case. Doing this kind of rebinding feels to me like a better approach most of the time.

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cjgillot commented Oct 6, 2021

@cjgillot, I see that you touched this file. Do you know if there's any reliance on predicates_of changing when trait modifiers like pub and unsafe are changed? Currently they do because the change of the span, but with this PR's change, that's no longer true. Would it be reasonable to change the test to no longer look for that?

I don't know enough the trait solving algorithm to comment on the need for the value to change when pub and unsafe change. OTOH, I would consider that any incremental code that relies on span-related invalidation to work correctly would be a red flag. So IMHO, it's fine to update the test.

If you want confirmation, you'd need to ask to professional trait solvers like @jackh726.

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jackh726 commented Oct 6, 2021

If you want confirmation, you'd need to ask to professional trait solvers like @jackh726.

😂❤you give me too much credit

Do you know if there's any reliance on predicates_of changing when trait modifiers like pub and unsafe are changed?

I would be extremely surprised if this were the case. I imagine for everything but diagnostics, we throw away the span anyways.

--> $DIR/issue-83765.rs:9:31
|
LL | fn size(&self) -> [usize; Self::DIM];
| ^^^^^^^^^ required by this bound in `TensorSize::size`
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This seems… weird. Self::DIM is not a… bound, is it? Though it looks like this error itself is not quite correct in the first place.

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Associated consts in array length position cause these. It's a preexisting problem that it's only exposed here because of better obligation tracking.

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Looked through the test changes for now, there seem to be some unfortunate regressions at least from my perspective.

src/test/ui/error-codes/E0283.stderr Outdated Show resolved Hide resolved
|
= note: ...so that the type `T` will meet its required lifetime bounds...
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This looks like a regression?

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It kind of is, but I feel it is acceptable given how many other things improve by screwing this one up (by using DUMMY_SP for trait implicit obligations).

|
LL | fn bar<'a, T>() where T: 'a {}
| ^^ required by this bound in `Foo::bar`
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^
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This seems like a regression? Is it unavoidable?

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The previous note span was wrong :-|

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After the last change we no longer show this note (and arguably never should have).

@estebank estebank force-pushed the trait-bounds-are-tricky branch from aa1f6cf to 9b3dd9c Compare October 12, 2021 14:18
@estebank estebank force-pushed the trait-bounds-are-tricky branch from d12ff11 to 0df3c8f Compare October 13, 2021 14:32
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@apiraino apiraino added the T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. label Oct 14, 2021
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@estebank estebank force-pushed the trait-bounds-are-tricky branch from dae3bdd to 0d4fdb2 Compare October 15, 2021 15:00
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This seems very nice. r=me with one remaining nit.

compiler/rustc_typeck/src/check/compare_method.rs Outdated Show resolved Hide resolved
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@jackh726 jackh726 added S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Oct 21, 2021
@estebank estebank force-pushed the trait-bounds-are-tricky branch from 0d4fdb2 to a62418a Compare October 25, 2021 22:18
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@JohnCSimon JohnCSimon added S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. and removed S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. labels Nov 13, 2021
@estebank estebank force-pushed the trait-bounds-are-tricky branch from a62418a to 1cadfe6 Compare November 18, 2021 01:32
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@bors r=nagisa

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bors commented Nov 18, 2021

📌 Commit a8dcc87 has been approved by nagisa

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Finished benchmarking commit (b8e5ab2): comparison url.

Summary: This change led to large relevant mixed results 🤷 in compiler performance.

  • Large improvement in instruction counts (up to -5.0% on incr-unchanged builds of inflate)
  • Small regression in instruction counts (up to 1.1% on incr-unchanged builds of wg-grammar)

If you disagree with this performance assessment, please file an issue in rust-lang/rustc-perf.

Next Steps: If you can justify the regressions found in this perf run, please indicate this with @rustbot label: +perf-regression-triaged along with sufficient written justification. If you cannot justify the regressions please open an issue or create a new PR that fixes the regressions, add a comment linking to the newly created issue or PR, and then add the perf-regression-triaged label to this PR.

@rustbot label: +perf-regression

@rustbot rustbot added the perf-regression Performance regression. label Nov 21, 2021
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Visiting for weekly performance triage.

Many other PR's over the past week have observed a similar delta to incr-unchanged builds of inflate, so I am dismissing that change as spurious. (The current hypothesis is that it is due to rust-lang/rustc-perf#1105.)

Other than that, there were a broad set of small regressions. Putting aside the ones tagged with ? ("noisy"), there are 19 benchmarks that regressed by 0.10% to 0.42%. This seems like an acceptable cost.

@rustbot label: +perf-regression-triaged

@rustbot rustbot added the perf-regression-triaged The performance regression has been triaged. label Nov 23, 2021
wip-sync pushed a commit to NetBSD/pkgsrc-wip that referenced this pull request Jan 22, 2022
Pkgsrc changes:
 * Bump available bootstraps to 1.57.0.
 * For some reason, the vendor/libc checksums don't need fixing.
 * Bump required external LLVM to 12.0, according to upstream change log.
 * Adapt the Darwin linker patch.

(For some reason I've not figured out yet, cargo is a lot more
verbose while building, echoes the rustc invocation.)

Upstream changes:

Version 1.58.1 (2022-01-19)
===========================

* Fix race condition in `std::fs::remove_dir_all` ([CVE-2022-21658])
* [Handle captured arguments in the `useless_format` Clippy lint][clippy/8295]
* [Move `non_send_fields_in_send_ty` Clippy lint to nursery][clippy/8075]
* [Fix wrong error message displayed when some imports are missing][91254]
* [Fix rustfmt not formatting generated files from stdin][92912]

[CVE-2022-21658]: https://www.cve.org/CVERecord?id=CVE-2022-21658]
[91254]: rust-lang/rust#91254
[92912]: rust-lang/rust#92912
[clippy/8075]: rust-lang/rust-clippy#8075
[clippy/8295]: rust-lang/rust-clippy#8295

Version 1.58.0 (2022-01-13)
==========================

Language
--------

- [Format strings can now capture arguments simply by writing
  `{ident}` in the string.][90473] This works in all macros accepting
  format strings. Support for this in `panic!` (`panic!("{ident}")`)
  requires the 2021 edition; panic invocations in previous editions
  that appear to be trying to use this will result in a warning lint
  about not having the intended effect.
- [`*const T` pointers can now be dereferenced in const contexts.][89551]
- [The rules for when a generic struct implements `Unsize` have
  been relaxed.][90417]

Compiler
--------

- [Add LLVM CFI support to the Rust compiler][89652]
- [Stabilize -Z strip as -C strip][90058]. Note that while release
  builds already don't add debug symbols for the code you compile,
  the compiled standard library that ships with Rust includes debug
  symbols, so you may want to use the `strip` option to remove these
  symbols to produce smaller release binaries. Note that this release
  only includes support in rustc, not directly in cargo.
- [Add support for LLVM coverage mapping format versions 5 and 6][91207]
- [Emit LLVM optimization remarks when enabled with `-Cremark`][90833]
- [Update the minimum external LLVM to 12][90175]
- [Add `x86_64-unknown-none` at Tier 3*][89062]
- [Build musl dist artifacts with debuginfo enabled][90733]. When
  building release binaries using musl, you may want to use the newly
  stabilized strip option to remove these debug symbols, reducing
  the size of your binaries.
- [Don't abort compilation after giving a lint error][87337]
- [Error messages point at the source of trait bound obligations
  in more places][89580]

\* Refer to Rust's [platform support page][platform-support-doc] for more
   information on Rust's tiered platform support.

Libraries
---------

- [All remaining functions in the standard library have `#[must_use]`
  annotations where appropriate][89692], producing a warning when
  ignoring their return value. This helps catch mistakes such as
  expecting a function to mutate a value in place rather than return
  a new value.
- [Paths are automatically canonicalized on Windows for operations
  that support it][89174]
- [Re-enable debug checks for `copy` and `copy_nonoverlapping`][90041]
- [Implement `RefUnwindSafe` for `Rc<T>`][87467]
- [Make RSplit<T, P>: Clone not require T: Clone][90117]
- [Implement `Termination` for `Result<Infallible, E>`][88601].
  This allows writing `fn main() -> Result<Infallible, ErrorType>`,
  for a program whose successful exits never involve returning from
  `main` (for instance, a program that calls `exit`, or that uses
  `exec` to run another program).

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

- [`Metadata::is_symlink`]
- [`Path::is_symlink`]
- [`{integer}::saturating_div`]
- [`Option::unwrap_unchecked`]
- [`Result::unwrap_unchecked`]
- [`Result::unwrap_err_unchecked`]
- [`NonZero{unsigned}::is_power_of_two`]
- [`File::options`]

These APIs are now usable in const contexts:

- [`Duration::new`]
- [`Duration::checked_add`]
- [`Duration::saturating_add`]
- [`Duration::checked_sub`]
- [`Duration::saturating_sub`]
- [`Duration::checked_mul`]
- [`Duration::saturating_mul`]
- [`Duration::checked_div`]
- [`MaybeUninit::as_ptr`]
- [`MaybeUninit::as_mut_ptr`]
- [`MaybeUninit::assume_init`]
- [`MaybeUninit::assume_init_ref`]

Cargo
-----

- [Add --message-format for install command][cargo/10107]
- [Warn when alias shadows external subcommand][cargo/10082]

Rustdoc
-------

- [Show all Deref implementations recursively in rustdoc][90183]
- [Use computed visibility in rustdoc][88447]

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

- [Try all stable method candidates first before trying unstable
  ones][90329]. This change ensures that adding new nightly-only
  methods to the Rust standard library will not break code invoking
  methods of the same name from traits outside the standard library.
- Windows: [`std::process::Command` will no longer search the
  current directory for executables.][87704]
- [All proc-macro backward-compatibility lints are now deny-by-default.][88041]
- [proc_macro: Append .0 to unsuffixed float if it would otherwise
  become int token][90297]
- [Refactor weak symbols in std::sys::unix][90846]. This optimizes
  accesses to glibc functions, by avoiding the use of dlopen. This
  does not increase the [minimum expected version of
  glibc](https://doc.rust-lang.org/nightly/rustc/platform-support.html).
  However, software distributions that use symbol versions to detect
  library dependencies, and which take weak symbols into account in
  that analysis, may detect rust binaries as requiring newer versions
  of glibc.
- [rustdoc now rejects some unexpected semicolons in doctests][91026]

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

These changes provide no direct user facing benefits, but represent
significant improvements to the internals and overall performance
of rustc and related tools.

- [Implement coherence checks for negative trait impls][90104]
- [Add rustc lint, warning when iterating over hashmaps][89558]
- [Optimize live point computation][90491]
- [Enable verification for 1/32nd of queries loaded from disk][90361]
- [Implement version of normalize_erasing_regions that allows for
  normalization failure][91255]

[87337]: rust-lang/rust#87337
[87467]: rust-lang/rust#87467
[87704]: rust-lang/rust#87704
[88041]: rust-lang/rust#88041
[88300]: rust-lang/rust#88300
[88447]: rust-lang/rust#88447
[88601]: rust-lang/rust#88601
[88624]: rust-lang/rust#88624
[89062]: rust-lang/rust#89062
[89174]: rust-lang/rust#89174
[89542]: rust-lang/rust#89542
[89551]: rust-lang/rust#89551
[89558]: rust-lang/rust#89558
[89580]: rust-lang/rust#89580
[89652]: rust-lang/rust#89652
[89677]: rust-lang/rust#89677
[89951]: rust-lang/rust#89951
[90041]: rust-lang/rust#90041
[90058]: rust-lang/rust#90058
[90104]: rust-lang/rust#90104
[90117]: rust-lang/rust#90117
[90175]: rust-lang/rust#90175
[90183]: rust-lang/rust#90183
[90297]: rust-lang/rust#90297
[90329]: rust-lang/rust#90329
[90361]: rust-lang/rust#90361
[90417]: rust-lang/rust#90417
[90473]: rust-lang/rust#90473
[90491]: rust-lang/rust#90491
[90733]: rust-lang/rust#90733
[90833]: rust-lang/rust#90833
[90846]: rust-lang/rust#90846
[90896]: rust-lang/rust#90896
[91026]: rust-lang/rust#91026
[91207]: rust-lang/rust#91207
[91255]: rust-lang/rust#91255
[91301]: rust-lang/rust#91301
[cargo/10082]: rust-lang/cargo#10082
[cargo/10107]: rust-lang/cargo#10107
[`Metadata::is_symlink`]: https://doc.rust-lang.org/stable/std/fs/struct.Metadata.html#method.is_symlink
[`Path::is_symlink`]: https://doc.rust-lang.org/stable/std/path/struct.Path.html#method.is_symlink
[`{integer}::saturating_div`]: https://doc.rust-lang.org/stable/std/primitive.i8.html#method.saturating_div
[`Option::unwrap_unchecked`]: https://doc.rust-lang.org/stable/std/option/enum.Option.html#method.unwrap_unchecked
[`Result::unwrap_unchecked`]: https://doc.rust-lang.org/stable/std/result/enum.Result.html#method.unwrap_unchecked
[`Result::unwrap_err_unchecked`]: https://doc.rust-lang.org/stable/std/result/enum.Result.html#method.unwrap_err_unchecked
[`NonZero{unsigned}::is_power_of_two`]: https://doc.rust-lang.org/stable/std/num/struct.NonZeroU8.html#method.is_power_of_two
[`File::options`]: https://doc.rust-lang.org/stable/std/fs/struct.File.html#method.options
[`unix::process::ExitStatusExt::core_dumped`]: https://doc.rust-lang.org/stable/std/os/unix/process/trait.ExitStatusExt.html#tymethod.core_dumped
[`unix::process::ExitStatusExt::stopped_signal`]: https://doc.rust-lang.org/stable/std/os/unix/process/trait.ExitStatusExt.html#tymethod.stopped_signal
[`unix::process::ExitStatusExt::continued`]: https://doc.rust-lang.org/stable/std/os/unix/process/trait.ExitStatusExt.html#tymethod.continued
[`unix::process::ExitStatusExt::into_raw`]: https://doc.rust-lang.org/stable/std/os/unix/process/trait.ExitStatusExt.html#tymethod.into_raw
[`Duration::new`]: https://doc.rust-lang.org/stable/std/time/struct.Duration.html#method.new
[`Duration::checked_add`]: https://doc.rust-lang.org/stable/std/time/struct.Duration.html#method.checked_add
[`Duration::saturating_add`]: https://doc.rust-lang.org/stable/std/time/struct.Duration.html#method.saturating_add
[`Duration::checked_sub`]: https://doc.rust-lang.org/stable/std/time/struct.Duration.html#method.checked_sub
[`Duration::saturating_sub`]: https://doc.rust-lang.org/stable/std/time/struct.Duration.html#method.saturating_sub
[`Duration::checked_mul`]: https://doc.rust-lang.org/stable/std/time/struct.Duration.html#method.checked_mul
[`Duration::saturating_mul`]: https://doc.rust-lang.org/stable/std/time/struct.Duration.html#method.saturating_mul
[`Duration::checked_div`]: https://doc.rust-lang.org/stable/std/time/struct.Duration.html#method.checked_div
[`Duration::as_secs_f64`]: https://doc.rust-lang.org/stable/std/time/struct.Duration.html#method.as_secs_f64
[`Duration::as_secs_f32`]: https://doc.rust-lang.org/stable/std/time/struct.Duration.html#method.as_secs_f32
[`Duration::from_secs_f64`]: https://doc.rust-lang.org/stable/std/time/struct.Duration.html#method.from_secs_f64
[`Duration::from_secs_f32`]: https://doc.rust-lang.org/stable/std/time/struct.Duration.html#method.from_secs_f32
[`Duration::mul_f64`]: https://doc.rust-lang.org/stable/std/time/struct.Duration.html#method.mul_f64
[`Duration::mul_f32`]: https://doc.rust-lang.org/stable/std/time/struct.Duration.html#method.mul_f32
[`Duration::div_f64`]: https://doc.rust-lang.org/stable/std/time/struct.Duration.html#method.div_f64
[`Duration::div_f32`]: https://doc.rust-lang.org/stable/std/time/struct.Duration.html#method.div_f32
[`Duration::div_duration_f64`]: https://doc.rust-lang.org/stable/std/time/struct.Duration.html#method.div_duration_f64
[`Duration::div_duration_f32`]: https://doc.rust-lang.org/stable/std/time/struct.Duration.html#method.div_duration_f32
[`MaybeUninit::as_ptr`]: https://doc.rust-lang.org/stable/std/mem/union.MaybeUninit.html#method.as_ptr
[`MaybeUninit::as_mut_ptr`]: https://doc.rust-lang.org/stable/std/mem/union.MaybeUninit.html#method.as_mut_ptr
[`MaybeUninit::assume_init`]: https://doc.rust-lang.org/stable/std/mem/union.MaybeUninit.html#method.assume_init
[`MaybeUninit::assume_init_ref`]: https://doc.rust-lang.org/stable/std/mem/union.MaybeUninit.html#method.assume_init_ref
netbsd-srcmastr pushed a commit to NetBSD/pkgsrc that referenced this pull request Mar 1, 2022
Pkgsrc changes:
 * Bump bootstrap kit version to 1.57.0.
 * Bump require external LLVM to 12.0, according to upstream change log.
 * Adjust patches as needed, adjust line numbers.
 * Update checksum adjustments.  For some reason the vendor/libc checksum
   doesn't need fixing, apparently, it remains as commented out.
 * Add makefile to do all the NetBSD boostrap/cross builds (do-cross.mk).
   Allow passing in additions to CONFIGURE_ARGS via ADD_CONFIGURE_ARGS.

Upstream changes:

Version 1.58.1 (2022-01-19)
===========================

* Fix race condition in `std::fs::remove_dir_all` ([CVE-2022-21658])
* [Handle captured arguments in the `useless_format` Clippy lint][clippy/8295]
* [Move `non_send_fields_in_send_ty` Clippy lint to nursery][clippy/8075]
* [Fix wrong error message displayed when some imports are missing][91254]
* [Fix rustfmt not formatting generated files from stdin][92912]

[CVE-2022-21658]: https://www.cve.org/CVERecord?id=CVE-2022-21658]
[91254]: rust-lang/rust#91254
[92912]: rust-lang/rust#92912
[clippy/8075]: rust-lang/rust-clippy#8075
[clippy/8295]: rust-lang/rust-clippy#8295

Version 1.58.0 (2022-01-13)
==========================

Language
--------

- [Format strings can now capture arguments simply by writing
  `{ident}` in the string.][90473] This works in all macros accepting
  format strings. Support for this in `panic!` (`panic!("{ident}")`)
  requires the 2021 edition; panic invocations in previous editions
  that appear to be trying to use this will result in a warning lint
  about not having the intended effect.
- [`*const T` pointers can now be dereferenced in const contexts.][89551]
- [The rules for when a generic struct implements `Unsize` have
  been relaxed.][90417]

Compiler
--------

- [Add LLVM CFI support to the Rust compiler][89652]
- [Stabilize -Z strip as -C strip][90058]. Note that while release
  builds already don't add debug symbols for the code you compile,
  the compiled standard library that ships with Rust includes debug
  symbols, so you may want to use the `strip` option to remove these
  symbols to produce smaller release binaries. Note that this release
  only includes support in rustc, not directly in cargo.
- [Add support for LLVM coverage mapping format versions 5 and 6][91207]
- [Emit LLVM optimization remarks when enabled with `-Cremark`][90833]
- [Update the minimum external LLVM to 12][90175]
- [Add `x86_64-unknown-none` at Tier 3*][89062]
- [Build musl dist artifacts with debuginfo enabled][90733]. When
  building release binaries using musl, you may want to use the newly
  stabilized strip option to remove these debug symbols, reducing
  the size of your binaries.
- [Don't abort compilation after giving a lint error][87337]
- [Error messages point at the source of trait bound obligations
  in more places][89580]

\* Refer to Rust's [platform support page][platform-support-doc] for more
   information on Rust's tiered platform support.

Libraries
---------

- [All remaining functions in the standard library have `#[must_use]`
  annotations where appropriate][89692], producing a warning when
  ignoring their return value. This helps catch mistakes such as
  expecting a function to mutate a value in place rather than return
  a new value.
- [Paths are automatically canonicalized on Windows for operations
  that support it][89174]
- [Re-enable debug checks for `copy` and `copy_nonoverlapping`][90041]
- [Implement `RefUnwindSafe` for `Rc<T>`][87467]
- [Make RSplit<T, P>: Clone not require T: Clone][90117]
- [Implement `Termination` for `Result<Infallible, E>`][88601].
  This allows writing `fn main() -> Result<Infallible, ErrorType>`,
  for a program whose successful exits never involve returning from
  `main` (for instance, a program that calls `exit`, or that uses
  `exec` to run another program).

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

- [`Metadata::is_symlink`]
- [`Path::is_symlink`]
- [`{integer}::saturating_div`]
- [`Option::unwrap_unchecked`]
- [`Result::unwrap_unchecked`]
- [`Result::unwrap_err_unchecked`]
- [`NonZero{unsigned}::is_power_of_two`]
- [`File::options`]

These APIs are now usable in const contexts:

- [`Duration::new`]
- [`Duration::checked_add`]
- [`Duration::saturating_add`]
- [`Duration::checked_sub`]
- [`Duration::saturating_sub`]
- [`Duration::checked_mul`]
- [`Duration::saturating_mul`]
- [`Duration::checked_div`]
- [`MaybeUninit::as_ptr`]
- [`MaybeUninit::as_mut_ptr`]
- [`MaybeUninit::assume_init`]
- [`MaybeUninit::assume_init_ref`]

Cargo
-----

- [Add --message-format for install command][cargo/10107]
- [Warn when alias shadows external subcommand][cargo/10082]

Rustdoc
-------

- [Show all Deref implementations recursively in rustdoc][90183]
- [Use computed visibility in rustdoc][88447]

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

- [Try all stable method candidates first before trying unstable
  ones][90329]. This change ensures that adding new nightly-only
  methods to the Rust standard library will not break code invoking
  methods of the same name from traits outside the standard library.
- Windows: [`std::process::Command` will no longer search the
  current directory for executables.][87704]
- [All proc-macro backward-compatibility lints are now deny-by-default.][88041]
- [proc_macro: Append .0 to unsuffixed float if it would otherwise
  become int token][90297]
- [Refactor weak symbols in std::sys::unix][90846]. This optimizes
  accesses to glibc functions, by avoiding the use of dlopen. This
  does not increase the [minimum expected version of
  glibc](https://doc.rust-lang.org/nightly/rustc/platform-support.html).
  However, software distributions that use symbol versions to detect
  library dependencies, and which take weak symbols into account in
  that analysis, may detect rust binaries as requiring newer versions
  of glibc.
- [rustdoc now rejects some unexpected semicolons in doctests][91026]

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

These changes provide no direct user facing benefits, but represent
significant improvements to the internals and overall performance
of rustc and related tools.

- [Implement coherence checks for negative trait impls][90104]
- [Add rustc lint, warning when iterating over hashmaps][89558]
- [Optimize live point computation][90491]
- [Enable verification for 1/32nd of queries loaded from disk][90361]
- [Implement version of normalize_erasing_regions that allows for
  normalization failure][91255]

[87337]: rust-lang/rust#87337
[87467]: rust-lang/rust#87467
[87704]: rust-lang/rust#87704
[88041]: rust-lang/rust#88041
[88300]: rust-lang/rust#88300
[88447]: rust-lang/rust#88447
[88601]: rust-lang/rust#88601
[88624]: rust-lang/rust#88624
[89062]: rust-lang/rust#89062
[89174]: rust-lang/rust#89174
[89542]: rust-lang/rust#89542
[89551]: rust-lang/rust#89551
[89558]: rust-lang/rust#89558
[89580]: rust-lang/rust#89580
[89652]: rust-lang/rust#89652
[89677]: rust-lang/rust#89677
[89951]: rust-lang/rust#89951
[90041]: rust-lang/rust#90041
[90058]: rust-lang/rust#90058
[90104]: rust-lang/rust#90104
[90117]: rust-lang/rust#90117
[90175]: rust-lang/rust#90175
[90183]: rust-lang/rust#90183
[90297]: rust-lang/rust#90297
[90329]: rust-lang/rust#90329
[90361]: rust-lang/rust#90361
[90417]: rust-lang/rust#90417
[90473]: rust-lang/rust#90473
[90491]: rust-lang/rust#90491
[90733]: rust-lang/rust#90733
[90833]: rust-lang/rust#90833
[90846]: rust-lang/rust#90846
[90896]: rust-lang/rust#90896
[91026]: rust-lang/rust#91026
[91207]: rust-lang/rust#91207
[91255]: rust-lang/rust#91255
[91301]: rust-lang/rust#91301
[cargo/10082]: rust-lang/cargo#10082
[cargo/10107]: rust-lang/cargo#10107
[`Metadata::is_symlink`]: https://doc.rust-lang.org/stable/std/fs/struct.Metadata.html#method.is_symlink
[`Path::is_symlink`]: https://doc.rust-lang.org/stable/std/path/struct.Path.html#method.is_symlink
[`{integer}::saturating_div`]: https://doc.rust-lang.org/stable/std/primitive.i8.html#method.saturating_div
[`Option::unwrap_unchecked`]: https://doc.rust-lang.org/stable/std/option/enum.Option.html#method.unwrap_unchecked
[`Result::unwrap_unchecked`]: https://doc.rust-lang.org/stable/std/result/enum.Result.html#method.unwrap_unchecked
[`Result::unwrap_err_unchecked`]: https://doc.rust-lang.org/stable/std/result/enum.Result.html#method.unwrap_err_unchecked
[`NonZero{unsigned}::is_power_of_two`]: https://doc.rust-lang.org/stable/std/num/struct.NonZeroU8.html#method.is_power_of_two
[`File::options`]: https://doc.rust-lang.org/stable/std/fs/struct.File.html#method.options
[`unix::process::ExitStatusExt::core_dumped`]: https://doc.rust-lang.org/stable/std/os/unix/process/trait.ExitStatusExt.html#tymethod.core_dumped
[`unix::process::ExitStatusExt::stopped_signal`]: https://doc.rust-lang.org/stable/std/os/unix/process/trait.ExitStatusExt.html#tymethod.stopped_signal
[`unix::process::ExitStatusExt::continued`]: https://doc.rust-lang.org/stable/std/os/unix/process/trait.ExitStatusExt.html#tymethod.continued
[`unix::process::ExitStatusExt::into_raw`]: https://doc.rust-lang.org/stable/std/os/unix/process/trait.ExitStatusExt.html#tymethod.into_raw
[`Duration::new`]: https://doc.rust-lang.org/stable/std/time/struct.Duration.html#method.new
[`Duration::checked_add`]: https://doc.rust-lang.org/stable/std/time/struct.Duration.html#method.checked_add
[`Duration::saturating_add`]: https://doc.rust-lang.org/stable/std/time/struct.Duration.html#method.saturating_add
[`Duration::checked_sub`]: https://doc.rust-lang.org/stable/std/time/struct.Duration.html#method.checked_sub
[`Duration::saturating_sub`]: https://doc.rust-lang.org/stable/std/time/struct.Duration.html#method.saturating_sub
[`Duration::checked_mul`]: https://doc.rust-lang.org/stable/std/time/struct.Duration.html#method.checked_mul
[`Duration::saturating_mul`]: https://doc.rust-lang.org/stable/std/time/struct.Duration.html#method.saturating_mul
[`Duration::checked_div`]: https://doc.rust-lang.org/stable/std/time/struct.Duration.html#method.checked_div
[`Duration::as_secs_f64`]: https://doc.rust-lang.org/stable/std/time/struct.Duration.html#method.as_secs_f64
[`Duration::as_secs_f32`]: https://doc.rust-lang.org/stable/std/time/struct.Duration.html#method.as_secs_f32
[`Duration::from_secs_f64`]: https://doc.rust-lang.org/stable/std/time/struct.Duration.html#method.from_secs_f64
[`Duration::from_secs_f32`]: https://doc.rust-lang.org/stable/std/time/struct.Duration.html#method.from_secs_f32
[`Duration::mul_f64`]: https://doc.rust-lang.org/stable/std/time/struct.Duration.html#method.mul_f64
[`Duration::mul_f32`]: https://doc.rust-lang.org/stable/std/time/struct.Duration.html#method.mul_f32
[`Duration::div_f64`]: https://doc.rust-lang.org/stable/std/time/struct.Duration.html#method.div_f64
[`Duration::div_f32`]: https://doc.rust-lang.org/stable/std/time/struct.Duration.html#method.div_f32
[`Duration::div_duration_f64`]: https://doc.rust-lang.org/stable/std/time/struct.Duration.html#method.div_duration_f64
[`Duration::div_duration_f32`]: https://doc.rust-lang.org/stable/std/time/struct.Duration.html#method.div_duration_f32
[`MaybeUninit::as_ptr`]: https://doc.rust-lang.org/stable/std/mem/union.MaybeUninit.html#method.as_ptr
[`MaybeUninit::as_mut_ptr`]: https://doc.rust-lang.org/stable/std/mem/union.MaybeUninit.html#method.as_mut_ptr
[`MaybeUninit::assume_init`]: https://doc.rust-lang.org/stable/std/mem/union.MaybeUninit.html#method.assume_init
[`MaybeUninit::assume_init_ref`]: https://doc.rust-lang.org/stable/std/mem/union.MaybeUninit.html#method.assume_init_ref
estebank added a commit to estebank/rust that referenced this pull request Mar 24, 2022
Instead of probing for all possible impls that could have caused an
`ImplObligation`, keep track of its `DefId` and obligation spans for
accurate error reporting.

Follow up to rust-lang#89580. Addresses rust-lang#89418.

Remove some unnecessary clones.

Tweak output for auto trait impl obligations.
bors added a commit to rust-lang-ci/rust that referenced this pull request Mar 24, 2022
…=oli-obk

Properly track `ImplObligations`

Instead of probing for all possible `impl`s that could have caused an
`ImplObligation`, keep track of its `DefId` and obligation spans for
accurate error reporting.

Follow to rust-lang#89580. Addresses rust-lang#89418.
matthiaskrgr added a commit to matthiaskrgr/rust that referenced this pull request Mar 8, 2023
…er-errors

Remove an unused return value in `rustc_hir_typeck`

Unused since rust-lang#89580. Just something I noticed a while ago.

`@rustbot` label C-cleanup
GuillaumeGomez added a commit to GuillaumeGomez/rust that referenced this pull request Sep 7, 2023
…ler-errors

diagnostics: add test case for trait bounds diagnostic

Closes rust-lang#82038

It was fixed by rust-lang#89580, a wide-reaching obligation tracking improvement. This commit adds a test case.
matthiaskrgr added a commit to matthiaskrgr/rust that referenced this pull request Sep 8, 2023
…ler-errors

diagnostics: add test case for trait bounds diagnostic

Closes rust-lang#82038

It was fixed by rust-lang#89580, a wide-reaching obligation tracking improvement. This commit adds a test case.
rust-timer added a commit to rust-lang-ci/rust that referenced this pull request Sep 8, 2023
Rollup merge of rust-lang#115649 - notriddle:notriddle/82038, r=compiler-errors

diagnostics: add test case for trait bounds diagnostic

Closes rust-lang#82038

It was fixed by rust-lang#89580, a wide-reaching obligation tracking improvement. This commit adds a test case.
@estebank estebank deleted the trait-bounds-are-tricky branch November 9, 2023 05:14
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