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2025-08-27Disable `int_to_ptr_transmutes` suggestion for unsized typesUrgau-13/+19
2025-08-24fix ICE on stable related to attrs on macrosJana Dönszelmann-29/+12
2025-08-24Port crate name to the new attribute systemJana Dönszelmann-57/+142
2025-08-24Support lints in early attribute parsingJana Dönszelmann-17/+53
2025-08-24Allow errors to be emitted as fatal during attribute parsingJana Dönszelmann-22/+66
2025-08-23Rollup merge of #145798 - compiler-errors:unnamed-lt-primary, r=lqdJacob Pratt-4/+4
Use unnamed lifetime spans as primary spans for `MISMATCHED_LIFETIME_SYNTAXES` Fixes https://github.com/rust-lang/rust/issues/145772 This PR changes the primary span(s) of the `MISMATCHED_LIFETIME_SYNTAXES` to point to the *unnamed* lifetime spans in both the inputs and *outputs* of the function signature. As reported in rust-lang/rust#145772, this should make it so that IDEs highlight the spans of the actionable part of this lint, rather than just the (possibly named) input spans like they do today. This could be tweaked further perhaps, for example for `fn foo(_: T<'_>) -> T`, we don't need to highlight the elided lifetime if the actionable part is to change only the return type to `T<'_>`, but I think it's improvement on what's here today, so I think that should be follow-up since I think the logic might get a bit hairy. cc ```@shepmaster```
2025-08-23Rollup merge of #144531 - Urgau:int_to_ptr_transmutes, r=jackh726Jacob Pratt-1/+143
Add lint against integer to pointer transmutes # `integer_to_ptr_transmutes` *warn-by-default* The `integer_to_ptr_transmutes` lint detects integer to pointer transmutes where the resulting pointers are undefined behavior to dereference. ### Example ```rust fn foo(a: usize) -> *const u8 { unsafe { std::mem::transmute::<usize, *const u8>(a) } } ``` ``` warning: transmuting an integer to a pointer creates a pointer without provenance --> a.rs:1:9 | 158 | std::mem::transmute::<usize, *const u8>(a) | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | = note: this is dangerous because dereferencing the resulting pointer is undefined behavior = note: exposed provenance semantics can be used to create a pointer based on some previously exposed provenance = help: if you truly mean to create a pointer without provenance, use `std::ptr::without_provenance_mut` = help: for more information about transmute, see <https://doc.rust-lang.org/std/mem/fn.transmute.html#transmutation-between-pointers-and-integers> = help: for more information about exposed provenance, see <https://doc.rust-lang.org/std/ptr/index.html#exposed-provenance> = note: `#[warn(integer_to_ptr_transmutes)]` on by default help: use `std::ptr::with_exposed_provenance` instead to use a previously exposed provenance | 158 - std::mem::transmute::<usize, *const u8>(a) 158 + std::ptr::with_exposed_provenance::<u8>(a) | ``` ### Explanation Any attempt to use the resulting pointers are undefined behavior as the resulting pointers won't have any provenance. Alternatively, `std::ptr::with_exposed_provenance` should be used, as they do not carry the provenance requirement or if the wanting to create pointers without provenance `std::ptr::without_provenance_mut` should be used. See [std::mem::transmute] in the reference for more details. [std::mem::transmute]: https://doc.rust-lang.org/std/mem/fn.transmute.html -------- People are getting tripped up on this, see https://github.com/rust-lang/rust/issues/128409 and https://github.com/rust-lang/rust/issues/141220. There are >90 cases like these on [GitHub search](https://github.com/search?q=lang%3Arust+%2Ftransmute%3A%3A%3Cu%5B0-9%5D*.*%2C+%5C*const%2F&type=code). Fixes https://github.com/rust-lang/rust-clippy/issues/13140 Fixes https://github.com/rust-lang/rust/issues/141220 Fixes https://github.com/rust-lang/rust/issues/145523 `@rustbot` labels +I-lang-nominated +T-lang cc `@traviscross` r? compiler
2025-08-23Auto merge of #145796 - samueltardieu:rollup-linfi86, r=samueltardieubors-160/+248
Rollup of 14 pull requests Successful merges: - rust-lang/rust#143898 (opt-dist: rebuild rustc when doing static LLVM builds) - rust-lang/rust#144452 (std/sys/fd: Relax `READ_LIMIT` on Darwin) - rust-lang/rust#145234 (match exhaustiveness diagnostics: show a trailing comma on singleton tuple consructors in witness patterns (and clean up a little)) - rust-lang/rust#145515 (Optimize `char::encode_utf8`) - rust-lang/rust#145540 (interpret/allocation: get_range on ProvenanceMap) - rust-lang/rust#145670 (port `sanitize` attribute to the new parsing infrastructure) - rust-lang/rust#145713 (next-solver: fix `feature(const_trait_impl)` bootstrap) - rust-lang/rust#145729 (Remove two duplicated crates) - rust-lang/rust#145744 (miri: also detect aliasing of in-place argument and return place) - rust-lang/rust#145774 (Remove default opts from config) - rust-lang/rust#145781 (Remove profile section from Clippy) - rust-lang/rust#145782 (rustdoc: make attributes render consistently) - rust-lang/rust#145787 (citool: cleanup `mismatched_lifetime_syntaxes` warnings) - rust-lang/rust#145791 (Fix ICE when validating transmuting ZST to inhabited enum) r? `@ghost` `@rustbot` modify labels: rollup
2025-08-23Use unnamed lifetime spans as primary spans for MISMATCHED_LIFETIME_SYNTAXESMichael Goulet-4/+4
2025-08-24Prefer verbose suggestions for `integer_to_ptr_transmutes` lintUrgau-2/+4
2025-08-24Add lint against integer to pointer transmutesUrgau-1/+141
2025-08-23Rollup merge of #145791 - samueltardieu:fix-zst-to-enum-mir-validation, ↵Samuel Tardieu-0/+15
r=compiler-errors Fix ICE when validating transmuting ZST to inhabited enum MIR validation attempts to determine the number of bytes needed to represent the size of the source type to compute the discriminant for the inhabited target enum. For a ZST source, there is no source data to use as a discriminant so no proper runtime check can be generated. Since that should never be possible, insert a delayed bug to ensure the problem has been properly reported to the user by the type checker. Fixes rust-lang/rust#145786
2025-08-23Rollup merge of #145744 - RalfJung:miri-inplace-aliasing, r=compiler-errorsSamuel Tardieu-7/+16
miri: also detect aliasing of in-place argument and return place This is a follow-up to https://github.com/rust-lang/rust/pull/145585 where I forgot to deal with the case of the return place aliasing an in-place argument -- as ``@Amanieu`` mentioned in https://github.com/rust-lang/rust/issues/71117#issuecomment-3212885817, that case must also be forbidden. r? ``@compiler-errors``
2025-08-23Rollup merge of #145713 - lcnr:const-trait-bootstrap, r=compiler-errorsSamuel Tardieu-9/+16
next-solver: fix `feature(const_trait_impl)` bootstrap rarw r? ``@compiler-errors`` ``@fee1-dead``
2025-08-23Rollup merge of #145670 - jdonszelmann:port-sanitize, r=lcnrSamuel Tardieu-127/+185
port `sanitize` attribute to the new parsing infrastructure
2025-08-23Rollup merge of #145540 - nia-e:prov-map-range, r=RalfJungSamuel Tardieu-0/+11
interpret/allocation: get_range on ProvenanceMap Helper method to grab all provenances in a given address range for an allocation, making some logic in Miri nicer.
2025-08-23Rollup merge of #145234 - dianne:1-tuple-witnesses, r=jackh726Samuel Tardieu-17/+5
match exhaustiveness diagnostics: show a trailing comma on singleton tuple consructors in witness patterns (and clean up a little) Constructor patterns of type `(T,)` are written `(pat,)`, not `(pat)`. However, exhaustiveness/usefulness diagnostics would print them as `(pat)` when e.g. providing a witness of non-exhaustiveness and suggesting adding arms to make matches exhaustive; this would result in an error when applied. rust-analyzer already prints the trailing comma, so it doesn't need changing. This also includes some cleanup in the second commit, with justification in the commit message.
2025-08-23Auto merge of #145706 - lcnr:uniquification, r=BoxyUwUbors-117/+159
change HIR typeck region uniquification handling approach rust-lang/rust#144405 causes structural lookup of opaque types to not work during HIR typeck, so instead avoid uniquifying goals and instead only reprove them if MIR borrowck actually encounters an error. This doesn't perfectly maintain the property that HIR typeck succeeding implies that MIR typeck succeeds, instead weakening this check to only guarantee that HIR typeck implies that MIR typeck succeeds modulo region uniquification. This means we still get the actually desirable ICEs if we MIR building is broken or we forget to check some property in HIR typeck, without having to deal with the fallout of uniquification in HIR typeck itself. We report errors using the original obligation sources of HIR typeck so diagnostics aren't that negatively impacted either. Here's the history of region uniquification while working on the new trait solver: - rust-lang/rust#107981 - rust-lang/rust#110180 - rust-lang/rust#114117 - rust-lang/rust#130821 - rust-lang/rust#144405 - rust-lang/rust#145706 <- we're here :tada: r? `@BoxyUwU`
2025-08-23Fix ICE when validating transmuting ZST to inhabited enumSamuel Tardieu-0/+15
MIR validation attempts to determine the number of bytes needed to represent the size of the source type to compute the discriminant for the inhabited target enum. For a ZST source, there is no source data to use as a discriminant so no proper runtime check can be generated. Since that should never be possible, insert a delayed bug to ensure the problem has been properly reported to the user by the type checker.
2025-08-23Auto merge of #145567 - clubby789:cargo_update, r=clubby789bors-1/+3
Weekly `cargo update` (with libc pin) Supersedes rust-lang/rust#145516 Manually pins libc for `compiler` and `rustbook` (both of which use rustix), with fixmes to remove this later. ``` compiler & tools dependencies: Locking 28 packages to latest compatible versions Updating anyhow v1.0.98 -> v1.0.99 Updating bitflags v2.9.1 -> v2.9.2 Updating clap v4.5.43 -> v4.5.45 Updating clap_builder v4.5.43 -> v4.5.44 Updating clap_derive v4.5.41 -> v4.5.45 Updating curl v0.4.48 -> v0.4.49 Updating curl-sys v0.4.82+curl-8.14.1 -> v0.4.83+curl-8.15.0 Updating cxx v1.0.166 -> v1.0.168 Updating cxx-build v1.0.166 -> v1.0.168 Updating cxxbridge-cmd v1.0.166 -> v1.0.168 Updating cxxbridge-flags v1.0.166 -> v1.0.168 Updating cxxbridge-macro v1.0.166 -> v1.0.168 Updating glob v0.3.2 -> v0.3.3 Updating object v0.37.2 -> v0.37.3 Updating proc-macro2 v1.0.95 -> v1.0.101 Updating rayon v1.10.0 -> v1.11.0 Updating rayon-core v1.12.1 -> v1.13.0 Updating serde-untagged v0.1.7 -> v0.1.8 Updating socket2 v0.5.10 -> v0.6.0 Updating syn v2.0.104 -> v2.0.106 Updating thiserror v2.0.12 -> v2.0.15 Updating thiserror-impl v2.0.12 -> v2.0.15 Updating uuid v1.17.0 -> v1.18.0 Updating wasm-encoder v0.236.0 -> v0.236.1 Updating wasmparser v0.236.0 -> v0.236.1 Updating wast v236.0.0 -> v236.0.1 Updating wat v1.236.0 -> v1.236.1 note: pass `--verbose` to see 35 unchanged dependencies behind latest library dependencies: Locking 2 packages to latest compatible versions Updating libc v0.2.174 -> v0.2.175 Updating object v0.37.2 -> v0.37.3 note: pass `--verbose` to see 2 unchanged dependencies behind latest rustbook dependencies: Locking 13 packages to latest compatible versions Updating anyhow v1.0.98 -> v1.0.99 Updating bitflags v2.9.1 -> v2.9.2 Updating cc v1.2.32 -> v1.2.33 Updating clap v4.5.43 -> v4.5.45 Updating clap_builder v4.5.43 -> v4.5.44 Updating clap_complete v4.5.56 -> v4.5.57 Updating clap_derive v4.5.41 -> v4.5.45 Updating proc-macro2 v1.0.95 -> v1.0.101 Updating syn v2.0.104 -> v2.0.106 Updating terminal_size v0.4.2 -> v0.4.3 Updating thiserror v2.0.12 -> v2.0.15 Updating thiserror-impl v2.0.12 -> v2.0.15 ```
2025-08-23port attribute to the new parsing infrastructureJana Dönszelmann-127/+185
2025-08-23Auto merge of #145506 - cjgillot:live-or-dead-onescan, r=fee1-deadbors-13/+16
Only scan each definition once for dead-code. r? `@ghost`
2025-08-23Auto merge of #145773 - jhpratt:rollup-kocqnzv, r=jhprattbors-759/+857
Rollup of 28 pull requests Successful merges: - rust-lang/rust#132087 (Fix overly restrictive lifetime in `core::panic::Location::file` return type) - rust-lang/rust#137396 (Recover `param: Ty = EXPR`) - rust-lang/rust#137457 (Fix host code appearing in Wasm binaries) - rust-lang/rust#142185 (Convert moves of references to copies in ReferencePropagation) - rust-lang/rust#144648 (Implementation: `#[feature(nonpoison_rwlock)]`) - rust-lang/rust#144897 (print raw lifetime idents with r#) - rust-lang/rust#145218 ([Debuginfo] improve enum value formatting in LLDB for better readability) - rust-lang/rust#145380 (Add codegen-llvm regression tests) - rust-lang/rust#145573 (Add an experimental unsafe(force_target_feature) attribute.) - rust-lang/rust#145597 (resolve: Remove `ScopeSet::Late`) - rust-lang/rust#145633 (Fix some typos in LocalKey documentation) - rust-lang/rust#145641 (On E0277, point at type that doesn't implement bound) - rust-lang/rust#145669 (rustdoc-search: GUI tests check for `//` in URL) - rust-lang/rust#145695 (Introduce ProjectionElem::try_map.) - rust-lang/rust#145710 (Fix the ABI parameter inconsistency issue in debug.rs for LoongArch64) - rust-lang/rust#145726 (Experiment: Reborrow trait) - rust-lang/rust#145731 (Make raw pointers work in type-based search) - rust-lang/rust#145736 (triagebot: Update style team reviewers) - rust-lang/rust#145738 (Uplift rustc_mir_transform::coverage::counters::union_find to rustc_data_structures.) - rust-lang/rust#145742 (rustdoc js: Even more typechecking improvments ) - rust-lang/rust#145743 (doc: fix some typos in comment) - rust-lang/rust#145745 (tests: Ignore basic-stepping.rs on LoongArch) - rust-lang/rust#145747 (Refactor lint buffering to avoid requiring a giant enum) - rust-lang/rust#145751 (fix(lexer): Allow '-' in the frontmatter infostring continue set) - rust-lang/rust#145761 (Add aarch64_be-unknown-hermit target) - rust-lang/rust#145762 (convert strings to symbols in attr diagnostics) - rust-lang/rust#145763 (Ship LLVM tools for the correct target when cross-compiling) - rust-lang/rust#145765 (Revert suggestions for missing methods in tuples) r? `@ghost` `@rustbot` modify labels: rollup
2025-08-22Rollup merge of #145765 - lqd:revert-142034, r=fmeaseJacob Pratt-121/+2
Revert suggestions for missing methods in tuples As requested by `@estebank` and as discussed with `@jackh726,` this reverts rust-lang/rust#142034 because of diagnostics ICEs like rust-lang/rust#142488 and its duplicates that have reached stable by now. We will work on a proper fix to reland this cool work in the near future, but in the meantime, a revert is safer to validate and backport to beta and stable, so here it is.
2025-08-22Rollup merge of #145762 - jdonszelmann:attrs-strings-to-symbols, r=lqdJacob Pratt-31/+36
convert strings to symbols in attr diagnostics r? `@lcnr` As you rightfully noticed in https://github.com/rust-lang/rust/pull/145670
2025-08-22Rollup merge of #145761 - Gelbpunkt:hermit-aarch64_be, r=wesleywiserJacob Pratt-0/+26
Add aarch64_be-unknown-hermit target Follow-up to rust-lang/rust#144962, which added the target necessary to build the Hermit bootloader and kernel for `aarch64_be`. This adds the target for Rust applications that can run in Hermit. I've been testing this for a while now and `@mkroening` and `@stlankes` are on board with adding this target. About the [tier 3 target policy](https://doc.rust-lang.org/rustc/target-tier-policy.html#tier-3-target-policy): > - A tier 3 target must have a designated developer or developers (the "target maintainers") on record to be CCed when issues arise regarding the target. (The mechanism to track and CC such developers may evolve over time.) The maintainers for this target are the same as for the other Hermit targets, `@mkroening` and `@stlankes.` > - Targets must use naming consistent with any existing targets; for instance, a target for the same CPU or OS as an existing Rust target should use the same name for that CPU or OS. Targets should normally use the same names and naming conventions as used elsewhere in the broader ecosystem beyond Rust (such as in other toolchains), unless they have a very good reason to diverge. Changing the name of a target can be highly disruptive, especially once the target reaches a higher tier, so getting the name right is important even for a tier 3 target. > - Target names should not introduce undue confusion or ambiguity unless absolutely necessary to maintain ecosystem compatibility. For example, if the name of the target makes people extremely likely to form incorrect beliefs about what it targets, the name should be changed or augmented to disambiguate it. > - If possible, use only letters, numbers, dashes and underscores for the name. Periods (.) are known to cause issues in Cargo. The target name is consistent with the existing `aarch64-unknown-hermit` target and the existing big endian aarch64 targets like `aarch64_be-unknown-linux-gnu`. > - Tier 3 targets may have unusual requirements to build or use, but must not create legal issues or impose onerous legal terms for the Rust project or for Rust developers or users. > - The target must not introduce license incompatibilities. > - Anything added to the Rust repository must be under the standard Rust license (MIT OR Apache-2.0). > - The target must not cause the Rust tools or libraries built for any other host (even when supporting cross-compilation to the target) to depend on any new dependency less permissive than the Rust licensing policy. This applies whether the dependency is a Rust crate that would require adding new license exceptions (as specified by the tidy tool in the rust-lang/rust repository), or whether the dependency is a native library or binary. In other words, the introduction of the target must not cause a user installing or running a version of Rust or the Rust tools to be subject to any new license requirements. > - Compiling, linking, and emitting functional binaries, libraries, or other code for the target (whether hosted on the target itself or cross-compiling from another target) must not depend on proprietary (non-FOSS) libraries. Host tools built for the target itself may depend on the ordinary runtime libraries supplied by the platform and commonly used by other applications built for the target, but those libraries must not be required for code generation for the target; cross-compilation to the target must not require such libraries at all. For instance, rustc built for the target may depend on a common proprietary C runtime library or console output library, but must not depend on a proprietary code generation library or code optimization library. Rust's license permits such combinations, but the Rust project has no interest in maintaining such combinations within the scope of Rust itself, even at tier 3. > - "onerous" here is an intentionally subjective term. At a minimum, "onerous" legal/licensing terms include but are not limited to: non-disclosure requirements, non-compete requirements, contributor license agreements (CLAs) or equivalent, "non-commercial"/"research-only"/etc terms, requirements conditional on the employer or employment of any particular Rust developers, revocable terms, any requirements that create liability for the Rust project or its developers or users, or any requirements that adversely affect the livelihood or prospects of the Rust project or its developers or users. There are no licensing issues or proprietary components required to compile for this target. > - Neither this policy nor any decisions made regarding targets shall create any binding agreement or estoppel by any party. If any member of an approving Rust team serves as one of the maintainers of a target, or has any legal or employment requirement (explicit or implicit) that might affect their decisions regarding a target, they must recuse themselves from any approval decisions regarding the target's tier status, though they may otherwise participate in discussions. > - This requirement does not prevent part or all of this policy from being cited in an explicit contract or work agreement (e.g. to implement or maintain support for a target). This requirement exists to ensure that a developer or team responsible for reviewing and approving a target does not face any legal threats or obligations that would prevent them from freely exercising their judgment in such approval, even if such judgment involves subjective matters or goes beyond the letter of these requirements. Ack. > - Tier 3 targets should attempt to implement as much of the standard libraries as possible and appropriate (core for most targets, alloc for targets that can support dynamic memory allocation, std for targets with an operating system or equivalent layer of system-provided functionality), but may leave some code unimplemented (either unavailable or stubbed out as appropriate), whether because the target makes it impossible to implement or challenging to implement. The authors of pull requests are not obligated to avoid calling any portions of the standard library on the basis of a tier 3 target not implementing those portions. This target implements std with the same featureset as `aarch64-unknown-hermit`. > - The target must provide documentation for the Rust community explaining how to build for the target, using cross-compilation if possible. If the target supports running binaries, or running tests (even if they do not pass), the documentation must explain how to run such binaries or tests for the target, using emulation if possible or dedicated hardware if necessary. Ack, that is part of the markdown document. > - Tier 3 targets must not impose burden on the authors of pull requests, or other developers in the community, to maintain the target. In particular, do not post comments (automated or manual) on a PR that derail or suggest a block on the PR based on a tier 3 target. Do not send automated messages or notifications (via any medium, including via `@)` to a PR author or others involved with a PR regarding a tier 3 target, unless they have opted into such messages. > - Backlinks such as those generated by the issue/PR tracker when linking to an issue or PR are not considered a violation of this policy, within reason. However, such messages (even on a separate repository) must not generate notifications to anyone involved with a PR who has not requested such notifications. Ack. > - Patches adding or updating tier 3 targets must not break any existing tier 2 or tier 1 target, and must not knowingly break another tier 3 target without approval of either the compiler team or the maintainers of the other tier 3 target. > - In particular, this may come up when working on closely related targets, such as variations of the same architecture with different features. Avoid introducing unconditional uses of features that another variation of the target may not have; use conditional compilation or runtime detection, as appropriate, to let each target run code supported by that target. This doesn't break any existing targets. > - Tier 3 targets must be able to produce assembly using at least one of rustc's supported backends from any host target. (Having support in a fork of the backend is not sufficient, it must be upstream.) The LLVM backend works. > - If a tier 3 target stops meeting these requirements, or the target maintainers no longer have interest or time, or the target shows no signs of activity and has not built for some time, or removing the target would improve the quality of the Rust codebase, we may post a PR to remove it; any such PR will be CCed to the target maintainers (and potentially other people who have previously worked on the target), to check potential interest in improving the situation. Ack. r? compiler_leads
2025-08-22Rollup merge of #145751 - epage:infostring, r=joshtriplettJacob Pratt-2/+2
fix(lexer): Allow '-' in the frontmatter infostring continue set This more closely matches the RFC and what our T-lang contact has asked for, see https://github.com/rust-lang/rust/issues/136889#issuecomment-3212715312 Tracking issue: rust-lang/rust#136889
2025-08-22Rollup merge of #145747 - joshtriplett:builtin-diag-dyn, r=jdonszelmannJacob Pratt-276/+264
Refactor lint buffering to avoid requiring a giant enum Lint buffering currently relies on a giant enum `BuiltinLintDiag` containing all the lints that might potentially get buffered. In addition to being an unwieldy enum in a central crate, this also makes `rustc_lint_defs` a build bottleneck: it depends on various types from various crates (with a steady pressure to add more), and many crates depend on it. Having all of these variants in a separate crate also prevents detecting when a variant becomes unused, which we can do with a dedicated type defined and used in the same crate. Refactor this to use a dyn trait, to allow using `LintDiagnostic` types directly. Because the existing `BuiltinLintDiag` requires some additional types in order to decorate some variants, which are only available later in `rustc_lint`, use an enum `DecorateDiagCompat` to handle both the `dyn LintDiagnostic` case and the `BuiltinLintDiag` case. --- With the infrastructure in place, use it to migrate three of the enum variants to use `LintDiagnostic` directly, as a proof of concept and to demonstrate that the net result is a reduction in code size and a removal of a boilerplate-heavy layer of indirection. Also remove an unused `BuiltinLintDiag` variant.
2025-08-22Rollup merge of #145738 - cjgillot:union-find-uplift, r=ZalatharJacob Pratt-8/+7
Uplift rustc_mir_transform::coverage::counters::union_find to rustc_data_structures. I was wondering if we had some union-find implementation in the compiler. We do. So put it where we can find it.
2025-08-22Rollup merge of #145726 - aapoalas:reborrow-lang-experiment, r=petrochenkovJacob Pratt-0/+5
Experiment: Reborrow trait Tracking issue: rust-lang/rust#145612 Starting off really small here: just introduce the unstable feature and the feature gate, and one of the two traits that the Reborrow experiment deals with. ### Cliff-notes explanation The `Reborrow` trait is conceptually a close cousin of `Copy` with the exception that it disables the source (`self`) for the lifetime of the target / result of the reborrow action. It can be viewed as a method of `fn reborrow(self: Self<'a>) -> Self<'a>` with the compiler adding tracking of the resulting `Self<'a>` (or any value derived from it that retains the `'a` lifetime) to keep the `self` disabled for reads and writes. No method is planned to be surfaced to the user, however, as reborrowing cannot be seen in code (except for method calls [`a.foo()` reborrows `a`] and explicit reborrows [`&*a`]) and thus triggering user-code in it could be viewed as "spooky action at a distance". Furthermore, the added compiler tracking cannot be seen on the method itself, violating the Golden Rule. Note that the userland "reborrow" method is not True Reborrowing, but rather a form of a "Fancy Deref": ```rust fn reborrow(&'short self: Self<'long>) -> Self<'short>; ``` The lifetime shortening is the issue here: a reborrowed `Self` or any value derived from it is bound to the method that called `reborrow`, since `&'short` is effectively a local variable. True Reborrowing does not shorten the lifetime of the result. To avoid having to introduce new kinds of references, new kinds of lifetime annotations, or a blessed trait method, no method will be introduced at all. Instead, the `Reborrow` trait is intended to be a derived trait that effectively reborrows each field individually; `Copy` fields end up just copying, while fields that themselves `Reborrow` get disabled in the source, usually leading to the source itself being disabled (some differences may appear with structs that contain multiple reborrowable fields). The goal of the experiment is to determine how the actual implementation here will shape out, and what the "bottom case" for the recursive / deriving `Reborrow` is. `Reborrow` has a friend trait, `CoerceShared`, which is equivalent to a `&'a mut T -> &'a T` conversion. This is needed as a different trait and different operation due to the different semantics it enforces on the source: a `CoerceShared` operation only disables the source for writes / exclusive access for the lifetime of the result. That trait is not yet introduced in this PR, though there is no particular reason why it could not be introduced.
2025-08-22Rollup merge of #145695 - cjgillot:place-elem-map, r=oli-obk,lcnrJacob Pratt-93/+66
Introduce ProjectionElem::try_map. Small utility function useful to manipulate MIR place projections.
2025-08-22Rollup merge of #145641 - estebank:point-at-type-in-e0277, r=davidtwcoJacob Pratt-55/+88
On E0277, point at type that doesn't implement bound When encountering an unmet trait bound, point at local type that doesn't implement the trait: ``` error[E0277]: the trait bound `Bar<T>: Foo` is not satisfied --> $DIR/issue-64855.rs:9:19 | LL | pub struct Bar<T>(<Self as Foo>::Type) where Self: ; | ^^^^^^^^^^^^^^^^^^^ unsatisfied trait bound | help: the trait `Foo` is not implemented for `Bar<T>` --> $DIR/issue-64855.rs:9:1 | LL | pub struct Bar<T>(<Self as Foo>::Type) where Self: ; | ^^^^^^^^^^^^^^^^^ ```
2025-08-22Rollup merge of #145597 - petrochenkov:nolateset, r=b-naberJacob Pratt-53/+62
resolve: Remove `ScopeSet::Late` It's better to decouple the late/early stage from scope set, because in https://github.com/rust-lang/rust/pull/144131#discussion_r2283200511 we'll need the stage for `ScopeSet::Module` as well. See individual commits for the refactoring details. r? ``@b-naber``
2025-08-22Rollup merge of #145573 - veluca93:unsafe-force-target-feature, r=davidtwcoJacob Pratt-58/+125
Add an experimental unsafe(force_target_feature) attribute. This uses the feature gate for https://github.com/rust-lang/rust/issues/143352, but is described in https://github.com/rust-lang/rfcs/pull/3820 which is strongly tied to the experiment.
2025-08-22Rollup merge of #144897 - fee1-dead-contrib:raw_lifetimes_printing, r=fmeaseJacob Pratt-57/+113
print raw lifetime idents with r# This replaces rust-lang/rust#143185 and fixes rust-lang/rust#143150 cc ``@fmease``
2025-08-22Rollup merge of #142185 - saethlin:refprop-moves, r=cjgillotJacob Pratt-3/+36
Convert moves of references to copies in ReferencePropagation This is a fix for https://github.com/rust-lang/rust/issues/141101. The root cause of this miscompile is that the SsaLocals analysis that MIR transforms use is supposed to detect locals that are only written to once, in their single assignment. But that analysis is subtly wrong; it does not consider `Operand::Move` to be a write even though the meaning ascribed to `Operand::Move` (at least as a function parameter) by Miri is that the callee may have done arbitrary writes to the caller's Local that the Operand wraps (because `Move` is pass-by-pointer). So Miri conwiders `Operand::Move` to be a write but both the MIR visitor system considers it a read, and so does SsaLocals. I have tried fixing this by changing the `PlaceContext` that is ascribed to an `Operand::Move` to a `MutatingUseContext` but that seems to have borrow checker implications, and changing SsaLocals seems to have wide-ranging regressions in MIR optimizations. So instead of doing those, this PR adds a new kludge to ReferencePropagation, which follows the same line of thinking as the kludge in CopyProp that solves this same problem inside that pass: https://github.com/rust-lang/rust/blob/a5584a8fe16037dc01782064fa41424a6dbe9987/compiler/rustc_mir_transform/src/copy_prop.rs#L65-L98
2025-08-22Rollup merge of #137396 - compiler-errors:param-default, r=fmeaseJacob Pratt-2/+25
Recover `param: Ty = EXPR` Fixes #137310 Pretty basic recovery here, but better than giving an unexpected token error.
2025-08-23Auto merge of #145469 - cjgillot:split-transmute, r=nnethercotebors-120/+131
Split transmute check from HIR typeck This resolves a FIXME in the implementation of `check_transmute`. `check_transmute` needs to compute type layout, hence needing to see reveal opaques and all type aliases. Having this inside typeck causes a cycle. For instance: `tests/ui/impl-trait/transmute/in-defining-scope.rs`. This PR moves the transmute check outside of typeck, by putting the list of deferred transmute checks in typeck results.
2025-08-22Auto merge of #145494 - cjgillot:span-decode-once, r=lqdbors-10/+9
Only unpack span data once to compute end_point and next_point. Split from https://github.com/rust-lang/rust/pull/144930
2025-08-22convert strings to symbols in attr diagnosticsJana Dönszelmann-31/+36
2025-08-22Revert "Detect method not being present that is present in other tuple types"Rémy Rakic-121/+2
This reverts commit 585a40963ea59808e74803f8610659a505b145e0.
2025-08-22Simplify implementation.Camille Gillot-44/+46
2025-08-22Separate transmute checking from typeck.Camille Gillot-119/+128
2025-08-22interpret/allocation: get_range on ProvenanceMapNia Espera-0/+11
2025-08-22Recover param: Ty = EXPRMichael Goulet-2/+25
2025-08-22Add aarch64_be-unknown-hermit targetJens Reidel-0/+26
Signed-off-by: Jens Reidel <adrian@travitia.xyz>
2025-08-22On E0277, point at type that doesn't implement boundEsteban Küber-55/+88
When encountering an unmet trait bound, point at local type that doesn't implement the trait: ``` error[E0277]: the trait bound `Bar<T>: Foo` is not satisfied --> $DIR/issue-64855.rs:9:19 | LL | pub struct Bar<T>(<Self as Foo>::Type) where Self: ; | ^^^^^^^^^^^^^^^^^^^ unsatisfied trait bound | help: the trait `Foo` is not implemented for `Bar<T>` --> $DIR/issue-64855.rs:9:1 | LL | pub struct Bar<T>(<Self as Foo>::Type) where Self: ; | ^^^^^^^^^^^^^^^^^ ```
2025-08-22fix(lexer): Allow '-' in the infostring continue setEd Page-2/+2
This more closely matches the RFC and what our T-lang contact has asked for, see https://github.com/rust-lang/rust/issues/136889#issuecomment-3212715312
2025-08-22resolve: Remove `ScopeSet::Late`Vadim Petrochenkov-23/+32
The difference between `Late` and `All` only matters when `finalize` is enabled. So add a `stage` field to `Finalize` and use it instead.
2025-08-22resolve: Remove derive fallback lint id from `ScopeSet::Late`Vadim Petrochenkov-11/+13