Implement coherence checks for negative trait impls #90104

spastorino · 2021-10-20T17:18:19Z

The main purpose of this PR is to be able to move Error trait to core.

This feature is necessary to handle the following from impl on box.

impl From<&str> for Box<dyn Error> { ... }

Without having negative traits affect coherence moving the error trait into core and moving that From impl to alloc will cause the from impl to no longer compiler because of a potential future incompatibility. The compiler indicates that &str could introduce an Error impl in the future, and thus prevents the From impl in alloc that would cause overlap with From<E: Error> for Box<dyn Error>. Adding impl !Error for &str {} with the negative trait coherence feature will disable this error by encoding a stability guarantee that &str will never implement Error, making the From impl compile.

We would have this in alloc:

impl From<&str> for Box<dyn Error> {} // A 
impl<E> From<E> for Box<dyn Error> where E: Error {} // B

and this in core:

trait Error {}
impl !Error for &str {}

r? @nikomatsakis

This PR was built on top of @yaahc PR #85764.

Language team proposal: to rust-lang/lang-team#96

…ually overlap

spastorino · 2021-10-20T17:58:18Z

@bors try @rust-timer queue

rust-timer · 2021-10-20T17:58:20Z

Awaiting bors try build completion.

@rustbot label: +S-waiting-on-perf

bors · 2021-10-20T17:58:27Z

⌛ Trying commit 68d444f with merge 2bf0405fabe34f62185aa4b41247aa4eed8b9785...

spastorino · 2021-10-20T18:10:22Z

rustdoc is failing, this is not unexpected :) and it's probably related to the handling of allow_negative_impls. Gonna check this quickly.

compiler/rustc_trait_selection/src/traits/coherence.rs

spastorino · 2021-10-21T12:08:53Z

@bors try @rust-timer queue

rust-timer · 2021-10-21T12:08:54Z

Awaiting bors try build completion.

@rustbot label: +S-waiting-on-perf

matthiaskrgr · 2021-10-23T03:59:32Z

@bors r- CI failed? :(

spastorino · 2021-10-23T12:02:24Z

@bors r=nikomatsakis

bors · 2021-10-23T12:02:25Z

📌 Commit 3287f72 has been approved by nikomatsakis

bors · 2021-10-23T12:51:18Z

⌛ Testing commit 3287f72 with merge aa5740c...

bors · 2021-10-23T15:53:44Z

☀️ Test successful - checks-actions
Approved by: nikomatsakis
Pushing aa5740c to master...

rust-timer · 2021-10-23T17:25:13Z

Finished benchmarking commit (aa5740c): comparison url.

Summary: This benchmark run did not return any relevant changes.

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

@rustbot label: -perf-regression

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

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

Don't treat negative trait predicates as always knowable We don't need this. It was added in rust-lang#90104 but I don't really know why. It's not sound afaict -- negative trait predicates need the same coherence-ambiguity/orphan check rules as positive ones. r? `@lcnr` cc `@spastorino,` do you remember why?

spastorino added 9 commits October 20, 2021 12:10

Add polarity to TraitPredicate

6975afd

Consider negative polarity on overlap check

8b0bfb0

Consider negative polarity on trait selection

ab17068

Test that if we promise to not impl what would overlap it doesn't act…

511076a

…ually overlap

Only assemble_candidates_from_impls for polarity Negative

da8873e

Make EvaluationCache consider polarity as cache's key

85c8fd9

Filter out Negative impls on intercrate mode's ambiguous reasoning

89a419c

Use predicate_must_hold_modulo_regions

6ae1d68

Filter candidates when goal and impl polarity doesn't match

7568632

rust-highfive assigned nikomatsakis Oct 20, 2021

rust-highfive added the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label Oct 20, 2021

This comment has been minimized.

Sign in to view

Add TraitObligation::polarity() for better encapsulation

68d444f

spastorino force-pushed the coherence-for-negative-trait branch from 0373be8 to 68d444f Compare October 20, 2021 17:45

rustbot added the S-waiting-on-perf Status: Waiting on a perf run to be completed. label Oct 20, 2021

This comment has been minimized.

Sign in to view

oli-obk reviewed Oct 20, 2021

View reviewed changes

compiler/rustc_trait_selection/src/traits/coherence.rs Outdated Show resolved Hide resolved

spastorino force-pushed the coherence-for-negative-trait branch from 8cb937e to 68d444f Compare October 20, 2021 18:50

This comment has been minimized.

Sign in to view

Fix allow_negative_impls logic

5a72753

spastorino force-pushed the coherence-for-negative-trait branch from f7a51d1 to 5a72753 Compare October 20, 2021 21:05

bors added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Oct 23, 2021

This comment has been minimized.

Sign in to view

bors 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-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. labels Oct 23, 2021

Avoid code duplication by extracting checks into fns

3287f72

spastorino force-pushed the coherence-for-negative-trait branch from 77ecd10 to 3287f72 Compare October 23, 2021 11:56

bors added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. labels Oct 23, 2021

bors added the merged-by-bors This PR was explicitly merged by bors. label Oct 23, 2021

bors merged commit aa5740c into rust-lang:master Oct 23, 2021

rustbot added this to the 1.58.0 milestone Oct 23, 2021

This was referenced Oct 23, 2021

Various fixes for const_trait_impl #89359

Merged

Check for duplicate attributes. #88681

Merged

Automatically implement AsRepr and allow deriving FromRepr for fieldless enums #81642

Closed

rustbot removed the perf-regression Performance regression. label Oct 23, 2021

This was referenced Oct 23, 2021

Implement coherence checks for negative trait impls #85764

Closed

Move Error trait into core rust-lang/project-error-handling#3

Open

Alexendoo mentioned this pull request Oct 24, 2021

ICE during codegen of function that can't be codegened #75961

Closed

spastorino mentioned this pull request Oct 25, 2021

Fix negative traits coherence checks compile error message for type aliases #90259

Open

compiler-errors mentioned this pull request Jul 26, 2023

Don't treat negative trait predicates as always knowable #114080

Merged

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Implement coherence checks for negative trait impls #90104

Implement coherence checks for negative trait impls #90104

spastorino commented Oct 20, 2021

This comment has been minimized.

spastorino commented Oct 20, 2021

rust-timer commented Oct 20, 2021

bors commented Oct 20, 2021

spastorino commented Oct 20, 2021

This comment has been minimized.

This comment has been minimized.

This comment has been minimized.

This comment has been minimized.

spastorino commented Oct 21, 2021

rust-timer commented Oct 21, 2021

This comment has been minimized.

matthiaskrgr commented Oct 23, 2021

spastorino commented Oct 23, 2021

bors commented Oct 23, 2021

bors commented Oct 23, 2021

bors commented Oct 23, 2021

rust-timer commented Oct 23, 2021

Implement coherence checks for negative trait impls #90104

Implement coherence checks for negative trait impls #90104

Conversation

spastorino commented Oct 20, 2021

This comment has been minimized.

spastorino commented Oct 20, 2021

rust-timer commented Oct 20, 2021

bors commented Oct 20, 2021

spastorino commented Oct 20, 2021

This comment has been minimized.

This comment has been minimized.

This comment has been minimized.

This comment has been minimized.

spastorino commented Oct 21, 2021

rust-timer commented Oct 21, 2021

This comment has been minimized.

matthiaskrgr commented Oct 23, 2021

spastorino commented Oct 23, 2021

bors commented Oct 23, 2021

bors commented Oct 23, 2021

bors commented Oct 23, 2021

rust-timer commented Oct 23, 2021