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

Conversation

This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.Learn more about bidirectional Unicode characters

[ Show hidden characters]({{ revealButtonHref }})

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: #123737 (comment)

rustbot added S-waiting-on-review

Status: Awaiting review from the assignee but also interested parties.

T-compiler

Relevant to the compiler team, which will review and decide on the PR/issue.

labels

Apr 10, 2024

bors added a commit to rust-lang-ci/rust that referenced this pull request

Apr 10, 2024

Check alias args for WF even if they have escaping bound vars

r? @ghost

☀️ Try build successful - checks-actions
Build commit: 5946bac (5946bac294aa8e579f74aa4a4d1f443d3b5d89f8)

This comment was marked as outdated.

This comment was marked as outdated.

🚧 Experiment pr-123737 is now running

ℹ️ Crater is a tool to run experiments across parts of the Rust ecosystem. Learn more

Well, this still isn't just enforcing alias types wf, since we also call compute_alias on projection predicates. Let me see what the fallout is just for alias types.

bors added a commit to rust-lang-ci/rust that referenced this pull request

Apr 15, 2024

Check alias args for WF even if they have escaping bound vars

r? @ghost

☀️ Try build successful - checks-actions
Build commit: 8d9ad77 (8d9ad7790f77ffaa434059a58807949d4583c045)

🚧 Experiment pr-123737-1 is now running

ℹ️ Crater is a tool to run experiments across parts of the Rust ecosystem. Learn more

🔔 This is now entering its final comment period, as per the review above. 🔔

That said, I don't think my concern needs to block this change...

@rfcbot reviewed

The final comment period, with a disposition to merge, as per the review above, is now complete.

As the automated representative of the governance process, I would like to thank the author for their work and everyone else who contributed.

This will be merged soon.

📌 Commit 994b58f has been approved by lcnr

It is now in the queue for this repository.

🌲 The tree is currently closed for pull requests below priority 100. This pull request will be tested once the tree is reopened.

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

Jul 2, 2024

Finished benchmarking commit (d163e5e): comparison URL.

Overall result: ❌✅ regressions and improvements - ACTION NEEDED

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
cc @rust-lang/wg-compiler-performance

Instruction count

This is a highly reliable metric that was used to determine the overall result at the top of this comment.

Max RSS (memory usage)

This benchmark run did not return any relevant results for this metric.

Cycles

Results (secondary 4.0%)

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

Binary size

This benchmark run did not return any relevant results for this metric.

Bootstrap: 695.519s -> 697.439s (0.28%)
Artifact size: 327.72 MiB -> 327.71 MiB (-0.00%)

I guess we're just doing slightly more work here? Not sure how we could fix this regression

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)

This change is required for further improvements of the type system, the compiler does a bit more work. The regression is limited to one stress test and one cargo benchmark.

@rustbot label: +perf-regression-triaged

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:

MR created with the help of el-capitano/tools/renovate-bot.

Proposed changes to behavior should be submitted there as MRs.

Release Notes

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.

• If you want to rebase/retry this MR, check this box

This MR has been generated by Renovate Bot.

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 in std context (where panics can have an arbitrary payload), while core::panic::PanicInfo is the argument to the #[panic_handler] 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 (or the given comparison function) does not implement a 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 in std context (where panics can have an arbitrary payload), while core::panic::PanicInfo is the argument to the #[panic_handler] 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 (or the given comparison function) does not implement a 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)