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std::error::Error
-> Trait Implementations: lifetimes consistency improvement
#113833
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Thanks for the pull request, and welcome! The Rust team is excited to review your changes, and you should hear from @joshtriplett (or someone else) soon. Please see the contribution instructions for more information. Namely, in order to ensure the minimum review times lag, PR authors and assigned reviewers should ensure that the review label (
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std::error::Error
-> Trait Implementations: lifetimes consistency improvement
@WiktorPrzetacznik Can you edit your post to include the reasoning to accept this PR instead of a link to a forum comment so I can kick this over to an FCP and that reasoning can be easily read and discussed by everyone instead of having to comb through that thread for context (or even to determine how much of that context is applicable)? Note that just copying the comment (with attribution) should be fine. |
@workingjubilee Thank you for the suggestion, reasoning is now included. |
Thanks! r? libs-api Requesting FCP for relaxing the lifetime constraints of these implementations for trait objects where they currently can imply the |
This reverts commit 3f1ad47.
@rust-lang/libs-api: This fixes the spurious lifetime error in code such as the following. fn main() {
let non_static_error = std::fmt::Error;
let mut boxed_error: Box<dyn std::error::Error> = Box::new(&non_static_error);
replace_error(&mut boxed_error);
}
fn replace_error(out: &mut impl From<String>) {
*out = "...".to_owned().into();
} error[E0597]: `non_static_error` does not live long enough
--> src/main.rs:3:64
|
2 | let non_static_error = std::fmt::Error;
| ---------------- binding `non_static_error` declared here
3 | let mut boxed_error: Box<dyn std::error::Error> = Box::new(&non_static_error);
| ---------^^^^^^^^^^^^^^^^^-
| | |
| | borrowed value does not live long enough
| cast requires that `non_static_error` is borrowed for `'static`
4 | replace_error(&mut boxed_error);
5 | }
| - `non_static_error` dropped here while still borrowed |
Team member @dtolnay has proposed to merge this. The next step is review by the rest of the tagged team members: Concerns:
Once a majority of reviewers approve (and at most 2 approvals are outstanding), this will enter its final comment period. If you spot a major issue that hasn't been raised at any point in this process, please speak up! See this document for info about what commands tagged team members can give me. |
Can we do a crater run for this change? It seems unlikely it will break anyone, but I think it would be good to check. I'm thinking in particular about regressions related to inference failures |
@rfcbot concern crater-run-first |
@bors try |
4 crates regressed with a "build failure" and all 4 look spurious to me. Out of memory, disk full, some kind of container disconnect. None of these could possibly be related to a compile error from the lifetimes change. @BurntSushi could you take a look as well, and resolve the concern? |
@rfcbot resolve crater-run-first |
🔔 This is now entering its final comment period, as per the review above. 🔔 |
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. |
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Thanks!
@bors r+ |
🌲 The tree is currently closed for pull requests below priority 100. This pull request will be tested once the tree is reopened. |
`std::error::Error` -> Trait Implementations: lifetimes consistency improvement This cleans up `std::error::Error` trait implementations lifetime inconsistency (`'static` -> `'a`) **Reasoning:** Trait implementations for `std::error::Error`, like: `impl From<&str> for Box<dyn Error + 'static, Global>` `impl<'a> From<&str> for Box<dyn Error + Sync + Send + 'a, Global>` use different lifetime annotations misleadingly implying using different life annotations here is a conscious, nonaccidental decision. [(Related forum discussion here)](https://users.rust-lang.org/t/confusing-std-error-source-code/97011/5?u=wiktor)
…iaskrgr Rollup of 7 pull requests Successful merges: - rust-lang#113833 (`std::error::Error` -> Trait Implementations: lifetimes consistency improvement) - rust-lang#115386 (PartialEq, PartialOrd: update and synchronize handling of transitive chains) - rust-lang#116284 (make matching on NaN a hard error, and remove the rest of illegal_floating_point_literal_pattern) - rust-lang#118960 (Add LocalWaker and ContextBuilder types to core, and LocalWake trait to alloc.) - rust-lang#120060 (Use the same mir-opt bless targets on all platforms) - rust-lang#120214 (match lowering: consistently lower bindings deepest-first) - rust-lang#120384 (Use `<T, U>` for array/slice equality `impl`s) r? `@ghost` `@rustbot` modify labels: rollup
`std::error::Error` -> Trait Implementations: lifetimes consistency improvement This cleans up `std::error::Error` trait implementations lifetime inconsistency (`'static` -> `'a`) **Reasoning:** Trait implementations for `std::error::Error`, like: `impl From<&str> for Box<dyn Error + 'static, Global>` `impl<'a> From<&str> for Box<dyn Error + Sync + Send + 'a, Global>` use different lifetime annotations misleadingly implying using different life annotations here is a conscious, nonaccidental decision. [(Related forum discussion here)](https://users.rust-lang.org/t/confusing-std-error-source-code/97011/5?u=wiktor)
…iaskrgr Rollup of 9 pull requests Successful merges: - rust-lang#113833 (`std::error::Error` -> Trait Implementations: lifetimes consistency improvement) - rust-lang#115386 (PartialEq, PartialOrd: update and synchronize handling of transitive chains) - rust-lang#116284 (make matching on NaN a hard error, and remove the rest of illegal_floating_point_literal_pattern) - rust-lang#118960 (Add LocalWaker and ContextBuilder types to core, and LocalWake trait to alloc.) - rust-lang#120384 (Use `<T, U>` for array/slice equality `impl`s) - rust-lang#120518 (riscv only supports split_debuginfo=off for now) - rust-lang#120619 (Assert that params with the same *index* have the same *name*) - rust-lang#120657 (Remove unused struct) - rust-lang#120661 (target: default to the medium code model on LoongArch targets) r? `@ghost` `@rustbot` modify labels: rollup
…iaskrgr Rollup of 8 pull requests Successful merges: - rust-lang#113833 (`std::error::Error` -> Trait Implementations: lifetimes consistency improvement) - rust-lang#115386 (PartialEq, PartialOrd: update and synchronize handling of transitive chains) - rust-lang#116284 (make matching on NaN a hard error, and remove the rest of illegal_floating_point_literal_pattern) - rust-lang#118960 (Add LocalWaker and ContextBuilder types to core, and LocalWake trait to alloc.) - rust-lang#120384 (Use `<T, U>` for array/slice equality `impl`s) - rust-lang#120518 (riscv only supports split_debuginfo=off for now) - rust-lang#120657 (Remove unused struct) - rust-lang#120661 (target: default to the medium code model on LoongArch targets) r? `@ghost` `@rustbot` modify labels: rollup
…iaskrgr Rollup of 8 pull requests Successful merges: - rust-lang#113833 (`std::error::Error` -> Trait Implementations: lifetimes consistency improvement) - rust-lang#115386 (PartialEq, PartialOrd: update and synchronize handling of transitive chains) - rust-lang#116284 (make matching on NaN a hard error, and remove the rest of illegal_floating_point_literal_pattern) - rust-lang#118960 (Add LocalWaker and ContextBuilder types to core, and LocalWake trait to alloc.) - rust-lang#120384 (Use `<T, U>` for array/slice equality `impl`s) - rust-lang#120518 (riscv only supports split_debuginfo=off for now) - rust-lang#120657 (Remove unused struct) - rust-lang#120661 (target: default to the medium code model on LoongArch targets) r? `@ghost` `@rustbot` modify labels: rollup
Rollup merge of rust-lang#113833 - WiktorPrzetacznik:master, r=dtolnay `std::error::Error` -> Trait Implementations: lifetimes consistency improvement This cleans up `std::error::Error` trait implementations lifetime inconsistency (`'static` -> `'a`) **Reasoning:** Trait implementations for `std::error::Error`, like: `impl From<&str> for Box<dyn Error + 'static, Global>` `impl<'a> From<&str> for Box<dyn Error + Sync + Send + 'a, Global>` use different lifetime annotations misleadingly implying using different life annotations here is a conscious, nonaccidental decision. [(Related forum discussion here)](https://users.rust-lang.org/t/confusing-std-error-source-code/97011/5?u=wiktor)
Pkgsrc changes: * Adapt checksums and patches, some have beene intregrated upstream. Upstream chnages: Version 1.78.0 (2024-05-02) =========================== Language -------- - [Stabilize `#[cfg(target_abi = ...)]`] (rust-lang/rust#119590) - [Stabilize the `#[diagnostic]` namespace and `#[diagnostic::on_unimplemented]` attribute] (rust-lang/rust#119888) - [Make async-fn-in-trait implementable with concrete signatures] (rust-lang/rust#120103) - [Make matching on NaN a hard error, and remove the rest of `illegal_floating_point_literal_pattern`] (rust-lang/rust#116284) - [static mut: allow mutable reference to arbitrary types, not just slices and arrays] (rust-lang/rust#117614) - [Extend `invalid_reference_casting` to include references casting to bigger memory layout] (rust-lang/rust#118983) - [Add `non_contiguous_range_endpoints` lint for singleton gaps after exclusive ranges] (rust-lang/rust#118879) - [Add `wasm_c_abi` lint for use of older wasm-bindgen versions] (rust-lang/rust#117918) This lint currently only works when using Cargo. - [Update `indirect_structural_match` and `pointer_structural_match` lints to match RFC] (rust-lang/rust#120423) - [Make non-`PartialEq`-typed consts as patterns a hard error] (rust-lang/rust#120805) - [Split `refining_impl_trait` lint into `_reachable`, `_internal` variants] (rust-lang/rust#121720) - [Remove unnecessary type inference when using associated types inside of higher ranked `where`-bounds] (rust-lang/rust#119849) - [Weaken eager detection of cyclic types during type inference] (rust-lang/rust#119989) - [`trait Trait: Auto {}`: allow upcasting from `dyn Trait` to `dyn Auto`] (rust-lang/rust#119338) Compiler -------- - [Made `INVALID_DOC_ATTRIBUTES` lint deny by default] (rust-lang/rust#111505) - [Increase accuracy of redundant `use` checking] (rust-lang/rust#117772) - [Suggest moving definition if non-found macro_rules! is defined later] (rust-lang/rust#121130) - [Lower transmutes from int to pointer type as gep on null] (rust-lang/rust#121282) Target changes: - [Windows tier 1 targets now require at least Windows 10] (rust-lang/rust#115141) - [Enable CMPXCHG16B, SSE3, SAHF/LAHF and 128-bit Atomics in tier 1 Windows] (rust-lang/rust#120820) - [Add `wasm32-wasip1` tier 2 (without host tools) target] (rust-lang/rust#120468) - [Add `wasm32-wasip2` tier 3 target] (rust-lang/rust#119616) - [Rename `wasm32-wasi-preview1-threads` to `wasm32-wasip1-threads`] (rust-lang/rust#122170) - [Add `arm64ec-pc-windows-msvc` tier 3 target] (rust-lang/rust#119199) - [Add `armv8r-none-eabihf` tier 3 target for the Cortex-R52] (rust-lang/rust#110482) - [Add `loongarch64-unknown-linux-musl` tier 3 target] (rust-lang/rust#121832) Refer to Rust's [platform support page][platform-support-doc] for more information on Rust's tiered platform support. Libraries --------- - [Bump Unicode to version 15.1.0, regenerate tables] (rust-lang/rust#120777) - [Make align_offset, align_to well-behaved in all cases] (rust-lang/rust#121201) - [PartialEq, PartialOrd: document expectations for transitive chains] (rust-lang/rust#115386) - [Optimize away poison guards when std is built with panic=abort] (rust-lang/rust#100603) - [Replace pthread `RwLock` with custom implementation] (rust-lang/rust#110211) - [Implement unwind safety for Condvar on all platforms] (rust-lang/rust#121768) - [Add ASCII fast-path for `char::is_grapheme_extended`] (rust-lang/rust#121138) Stabilized APIs --------------- - [`impl Read for &Stdin`] (https://doc.rust-lang.org/stable/std/io/struct.Stdin.html#impl-Read-for-%26Stdin) - [Accept non `'static` lifetimes for several `std::error::Error` related implementations] (rust-lang/rust#113833) - [Make `impl<Fd: AsFd>` impl take `?Sized`] (rust-lang/rust#114655) - [`impl From<TryReserveError> for io::Error`] (https://doc.rust-lang.org/stable/std/io/struct.Error.html#impl-From%3CTryReserveError%3E-for-Error) These APIs are now stable in const contexts: - [`Barrier::new()`] (https://doc.rust-lang.org/stable/std/sync/struct.Barrier.html#method.new) Cargo ----- - [Stabilize lockfile v4](rust-lang/cargo#12852) - [Respect `rust-version` when generating lockfile] (rust-lang/cargo#12861) - [Control `--charset` via auto-detecting config value] (rust-lang/cargo#13337) - [Support `target.<triple>.rustdocflags` officially] (rust-lang/cargo#13197) - [Stabilize global cache data tracking] (rust-lang/cargo#13492) Misc ---- - [rustdoc: add `--test-builder-wrapper` arg to support wrappers such as RUSTC_WRAPPER when building doctests] (rust-lang/rust#114651) Compatibility Notes ------------------- - [Many unsafe precondition checks now run for user code with debug assertions enabled] (rust-lang/rust#120594) This change helps users catch undefined behavior in their code, though the details of how much is checked are generally not stable. - [riscv only supports split_debuginfo=off for now] (rust-lang/rust#120518) - [Consistently check bounds on hidden types of `impl Trait`] (rust-lang/rust#121679) - [Change equality of higher ranked types to not rely on subtyping] (rust-lang/rust#118247) - [When called, additionally check bounds on normalized function return type] (rust-lang/rust#118882) - [Expand coverage for `arithmetic_overflow` lint] (rust-lang/rust#119432) 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. - [Update to LLVM 18](rust-lang/rust#120055) - [Build `rustc` with 1CGU on `x86_64-pc-windows-msvc`] (rust-lang/rust#112267) - [Build `rustc` with 1CGU on `x86_64-apple-darwin`] (rust-lang/rust#112268) - [Introduce `run-make` V2 infrastructure, a `run_make_support` library and port over 2 tests as example] (rust-lang/rust#113026) - [Windows: Implement condvar, mutex and rwlock using futex] (rust-lang/rust#121956)
This cleans up
std::error::Error
trait implementations lifetime inconsistency ('static
->'a
)Reasoning:
Trait implementations for
std::error::Error
, like:impl From<&str> for Box<dyn Error + 'static, Global>
impl<'a> From<&str> for Box<dyn Error + Sync + Send + 'a, Global>
use different lifetime annotations misleadingly implying using different life annotations here is a conscious, nonaccidental decision.
(Related forum discussion here)