Uplift the let_underscore lints from clippy into rustc.
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This lint checks for statements similar to `let _ = foo`, where `foo` is a type that implements `Drop`. These types of let statements cause the expression in them to be dropped immediately, instead of at the end of the scope. Such behavior can be surprizing, especially if you are relying on the value to be dropped at the end of the scope. Instead, the binding should be an underscore prefixed name (like `_unused`) or the value should explicitly be passed to `std::mem::drop()` if the value really should be dropped immediately.
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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 @estebank (or someone else) soon. Please see the contribution instructions for more information. |
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Similar to `let_underscore_drop`, this lint checks for statements similar to `let _ = foo`, where `foo` is a lock guard. These types of let statements are especially problematic because the lock gets released immediately, instead of at the end of the scope. This behavior is almost always the wrong thing.
Similar to `let_underscore_drop`, this lint checks for statements similar to `let _ = foo`, where `foo` is an expression marked `must_use`.
This was done to pass `tidy`.
These lints are very noisy and are allow-by-default in clippy anyways. Hence, setting them to allow-by-default here makes more sense than warning constantly on these cases.
This commit uses `span_suggestion_verbose` to add what specific code changes can be done as suggested by the lint--in this case, either binding the expression to an unused variable or using `std::mem::drop` to drop the value explicitly.
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Clippy sets this lint to Deny by default, and it having the lint be Deny is useful for when we test the lint against a Crater run.
cjgillot
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Jun 4, 2022
| const SYNC_GUARD_PATHS: [&[&str]; 5] = [ | ||
| &["std", "sync", "mutex", "MutexGuard"], | ||
| &["std", "sync", "rwlock", "RwLockReadGuard"], | ||
| &["std", "sync", "rwlock", "RwLockWriteGuard"], |
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Can those paths be replaced by diagnostic items? This will make all this more robust to code being moved within std.
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These paths were taken directly from the clippy implementation (which is also why they're hardcoded right now--there is a clippy issue meant to address that for clippy though). I can add a diagnostic item for these types, but I'm wondering if something similar to clippy's has_significant_drop already exists? It would make the lint much easier to implement and would generalize to other types well.
For now, however, I've added some diagnostic items.
| &["std", "sync", "rwlock", "RwLockReadGuard"], | ||
| &["std", "sync", "rwlock", "RwLockWriteGuard"], | ||
| &["parking_lot", "raw_mutex", "RawMutex"], | ||
| &["parking_lot", "raw_rwlock", "RawRwLock"], |
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I don't know the policy here: is rustc supposed to warn on inappropriate use of non-std crates?
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I'll remove the parking_lot specific paths for now, unless someone wants to keep them in.
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If the type has a trivial Drop implementation, then it is probably irrelevant that the type was dropped immediately, since nothing important happens on drop. Hence, we can bail out early instead of doing some expensive checks.
…lock` Using diagnostic items avoids having to update the paths if the guard types ever get moved around for some reason. Additionally, it also greatly simplifies the `is_sync_lock` check.
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👍 for adding Adding However, I'm not sure I understand the value of |
I added it to match the corresponding clippy lint, but I think you're right--if people really want it, clippy would probably be a more appropriate tool for that, I'll remove |
We don't actually care about running these programs, only checking the warnings they generate.
The `let_underscore_must_use` lint was really only added because clippy included it, but it doesn't actually seem very useful.
I forgot to add the diagnostic to the actual types in `std` earlier.
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…llaumeGomez Rollup of 9 pull requests Successful merges: - rust-lang#97739 (Uplift the `let_underscore` lints from clippy into rustc.) - rust-lang#99583 (Add additional methods to the Demand type) - rust-lang#100147 (optimization of access level table construction) - rust-lang#100552 (rustc_target: Add a compatibility layer to separate internal and user-facing linker flavors) - rust-lang#100827 (Simplify MIR opt tests) - rust-lang#101166 (Generate error index with mdbook instead of raw HTML pages) - rust-lang#101294 (Fix rust-lang#100844 rebase accident) - rust-lang#101298 (rustdoc: remove unused CSS `#main-content > .since`) - rust-lang#101304 (Add autolabels for `A-query-system`) Failed merges: r? `@ghost` `@rustbot` modify labels: rollup
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For whatever reason, the #![cfg_attr(feature = "cargo-clippy", allow(let_underscore_drop))] attributes already in the code stopped working in the most recent nightly (2022-09-03). Likely in connection with rust-lang/rust#97739 ? error: non-binding `let` on a type that implements `Drop` --> build.rs:8:5 | 8 | let _ = fs::remove_dir_all(&out_dir); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | = note: `-D clippy::let-underscore-drop` implied by `-D clippy::pedantic` = help: consider using an underscore-prefixed named binding or dropping explicitly with `std::mem::drop` = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#let_underscore_drop error: non-binding `let` on a type that implements `Drop` --> build.rs:9:5 | 9 | let _ = fs::create_dir(&out_dir); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | = help: consider using an underscore-prefixed named binding or dropping explicitly with `std::mem::drop` = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#let_underscore_drop error: non-binding `let` on a type that implements `Drop` --> src/lib.rs:128:5 | 128 | let _ = fs::create_dir(&p); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ | = note: `-D clippy::let-underscore-drop` implied by `-D clippy::pedantic` = help: consider using an underscore-prefixed named binding or dropping explicitly with `std::mem::drop` = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#let_underscore_drop
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For whatever reason, the #![cfg_attr(feature = "cargo-clippy", allow(let_underscore_drop))] attributes already in the code stopped working in the most recent nightly (2022-09-03). Likely in connection with rust-lang/rust#97739 ? error: non-binding `let` on a type that implements `Drop` --> serde/src/de/mod.rs:958:13 | 958 | let _ = visitor; | ^^^^^^^^^^^^^^^^ | = note: `-D clippy::let-underscore-drop` implied by `-D clippy::pedantic` = help: consider using an underscore-prefixed named binding or dropping explicitly with `std::mem::drop` = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#let_underscore_drop error: non-binding `let` on a type that implements `Drop` --> serde/src/de/mod.rs:992:13 | 992 | let _ = visitor; | ^^^^^^^^^^^^^^^^ | = help: consider using an underscore-prefixed named binding or dropping explicitly with `std::mem::drop` = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#let_underscore_drop error: non-binding `let` on a type that implements `Drop` --> serde/src/de/mod.rs:1616:9 | 1616 | let _ = deserializer; | ^^^^^^^^^^^^^^^^^^^^^ | = help: consider using an underscore-prefixed named binding or dropping explicitly with `std::mem::drop` = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#let_underscore_drop error: non-binding `let` on a type that implements `Drop` --> serde/src/de/mod.rs:1640:9 | 1640 | let _ = deserializer; | ^^^^^^^^^^^^^^^^^^^^^ | = help: consider using an underscore-prefixed named binding or dropping explicitly with `std::mem::drop` = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#let_underscore_drop error: non-binding `let` on a type that implements `Drop` --> serde/src/de/mod.rs:1651:9 | 1651 | let _ = seq; | ^^^^^^^^^^^^ | = help: consider using an underscore-prefixed named binding or dropping explicitly with `std::mem::drop` = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#let_underscore_drop error: non-binding `let` on a type that implements `Drop` --> serde/src/de/mod.rs:1662:9 | 1662 | let _ = map; | ^^^^^^^^^^^^ | = help: consider using an underscore-prefixed named binding or dropping explicitly with `std::mem::drop` = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#let_underscore_drop error: non-binding `let` on a type that implements `Drop` --> serde/src/de/mod.rs:1673:9 | 1673 | let _ = data; | ^^^^^^^^^^^^^ | = help: consider using an underscore-prefixed named binding or dropping explicitly with `std::mem::drop` = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#let_underscore_drop error: non-binding `let` on a type that implements `Drop` --> serde/src/private/de.rs:1440:13 | 1440 | let _ = visitor; | ^^^^^^^^^^^^^^^^ | = help: consider using an underscore-prefixed named binding or dropping explicitly with `std::mem::drop` = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#let_underscore_drop error: non-binding `let` on a type that implements `Drop` --> serde/src/private/de.rs:2163:13 | 2163 | let _ = visitor; | ^^^^^^^^^^^^^^^^ | = help: consider using an underscore-prefixed named binding or dropping explicitly with `std::mem::drop` = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#let_underscore_drop
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For whatever reason, the #![cfg_attr(feature = "cargo-clippy", allow(let_underscore_drop))] attributes already in the code stopped working in the most recent nightly (2022-09-03). Likely in connection with rust-lang/rust#97739 ? error: non-binding `let` on a type that implements `Drop` --> serde/src/de/mod.rs:958:13 | 958 | let _ = visitor; | ^^^^^^^^^^^^^^^^ | = note: `-D clippy::let-underscore-drop` implied by `-D clippy::pedantic` = help: consider using an underscore-prefixed named binding or dropping explicitly with `std::mem::drop` = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#let_underscore_drop error: non-binding `let` on a type that implements `Drop` --> serde/src/de/mod.rs:992:13 | 992 | let _ = visitor; | ^^^^^^^^^^^^^^^^ | = help: consider using an underscore-prefixed named binding or dropping explicitly with `std::mem::drop` = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#let_underscore_drop error: non-binding `let` on a type that implements `Drop` --> serde/src/de/mod.rs:1616:9 | 1616 | let _ = deserializer; | ^^^^^^^^^^^^^^^^^^^^^ | = help: consider using an underscore-prefixed named binding or dropping explicitly with `std::mem::drop` = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#let_underscore_drop error: non-binding `let` on a type that implements `Drop` --> serde/src/de/mod.rs:1640:9 | 1640 | let _ = deserializer; | ^^^^^^^^^^^^^^^^^^^^^ | = help: consider using an underscore-prefixed named binding or dropping explicitly with `std::mem::drop` = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#let_underscore_drop error: non-binding `let` on a type that implements `Drop` --> serde/src/de/mod.rs:1651:9 | 1651 | let _ = seq; | ^^^^^^^^^^^^ | = help: consider using an underscore-prefixed named binding or dropping explicitly with `std::mem::drop` = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#let_underscore_drop error: non-binding `let` on a type that implements `Drop` --> serde/src/de/mod.rs:1662:9 | 1662 | let _ = map; | ^^^^^^^^^^^^ | = help: consider using an underscore-prefixed named binding or dropping explicitly with `std::mem::drop` = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#let_underscore_drop error: non-binding `let` on a type that implements `Drop` --> serde/src/de/mod.rs:1673:9 | 1673 | let _ = data; | ^^^^^^^^^^^^^ | = help: consider using an underscore-prefixed named binding or dropping explicitly with `std::mem::drop` = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#let_underscore_drop error: non-binding `let` on a type that implements `Drop` --> serde/src/private/de.rs:1440:13 | 1440 | let _ = visitor; | ^^^^^^^^^^^^^^^^ | = help: consider using an underscore-prefixed named binding or dropping explicitly with `std::mem::drop` = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#let_underscore_drop error: non-binding `let` on a type that implements `Drop` --> serde/src/private/de.rs:2163:13 | 2163 | let _ = visitor; | ^^^^^^^^^^^^^^^^ | = help: consider using an underscore-prefixed named binding or dropping explicitly with `std::mem::drop` = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#let_underscore_drop
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For whatever reason, the #![cfg_attr(feature = "cargo-clippy", allow(let_underscore_drop))] attributes already in the code stopped working in the most recent nightly (2022-09-03). Likely in connection with rust-lang/rust#97739 ? error: non-binding `let` on a type that implements `Drop` --> serde/src/de/mod.rs:958:13 | 958 | let _ = visitor; | ^^^^^^^^^^^^^^^^ | = note: `-D clippy::let-underscore-drop` implied by `-D clippy::pedantic` = help: consider using an underscore-prefixed named binding or dropping explicitly with `std::mem::drop` = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#let_underscore_drop error: non-binding `let` on a type that implements `Drop` --> serde/src/de/mod.rs:992:13 | 992 | let _ = visitor; | ^^^^^^^^^^^^^^^^ | = help: consider using an underscore-prefixed named binding or dropping explicitly with `std::mem::drop` = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#let_underscore_drop error: non-binding `let` on a type that implements `Drop` --> serde/src/de/mod.rs:1616:9 | 1616 | let _ = deserializer; | ^^^^^^^^^^^^^^^^^^^^^ | = help: consider using an underscore-prefixed named binding or dropping explicitly with `std::mem::drop` = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#let_underscore_drop error: non-binding `let` on a type that implements `Drop` --> serde/src/de/mod.rs:1640:9 | 1640 | let _ = deserializer; | ^^^^^^^^^^^^^^^^^^^^^ | = help: consider using an underscore-prefixed named binding or dropping explicitly with `std::mem::drop` = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#let_underscore_drop error: non-binding `let` on a type that implements `Drop` --> serde/src/de/mod.rs:1651:9 | 1651 | let _ = seq; | ^^^^^^^^^^^^ | = help: consider using an underscore-prefixed named binding or dropping explicitly with `std::mem::drop` = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#let_underscore_drop error: non-binding `let` on a type that implements `Drop` --> serde/src/de/mod.rs:1662:9 | 1662 | let _ = map; | ^^^^^^^^^^^^ | = help: consider using an underscore-prefixed named binding or dropping explicitly with `std::mem::drop` = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#let_underscore_drop error: non-binding `let` on a type that implements `Drop` --> serde/src/de/mod.rs:1673:9 | 1673 | let _ = data; | ^^^^^^^^^^^^^ | = help: consider using an underscore-prefixed named binding or dropping explicitly with `std::mem::drop` = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#let_underscore_drop error: non-binding `let` on a type that implements `Drop` --> serde/src/private/de.rs:1440:13 | 1440 | let _ = visitor; | ^^^^^^^^^^^^^^^^ | = help: consider using an underscore-prefixed named binding or dropping explicitly with `std::mem::drop` = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#let_underscore_drop error: non-binding `let` on a type that implements `Drop` --> serde/src/private/de.rs:2163:13 | 2163 | let _ = visitor; | ^^^^^^^^^^^^^^^^ | = help: consider using an underscore-prefixed named binding or dropping explicitly with `std::mem::drop` = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#let_underscore_drop
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Mark `let_underscore_lock` and `let_underscore_drop` as uplifted Here I've renamed both the uplifted lints, however rustc's `let_underscore_lock` is slightly less capable than the clippy lint as it doesn't catch `parking_lot` types or `Result<Guard, ..>`, should we still remove it? The `Result` change looks like it was unintentional to me so that could probably be fixed upstream changelog: Uplift [`let_underscore_drop`] to rustc rust-lang/rust#97739 changelog: Remove overlap between rustc's `let_underscore_lock` and Clippy's [`let_underscore_lock`] r? `@flip1995`
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The 1.65.0 changelog says
But this comment and b5b5b54 seems to indicate that |
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Pkgsrc changes: * We now manage to build for mipsel-unknown-netbsd, but despite the target spec saying cpu = "mips3", the compiler manages to emit 64-bit instructions which cause "illegal instruction" error. Will need more work. The mipsel-unknown-netbsd entry is commentd out since there is no 1.64.0 bootstrap. * Managed to retain the build of aarch64_be, llvm needed a patch to avoid use of neon instructions in the BE case (llvm doesn't support use of neon in BE mode). Ref. patch to src/llvm-project/llvm/lib/Support/BLAKE3/blake3_impl.h. * The minimum gcc version is now 7.x, and that includes the cross-compiler for the targets. For i386 this also needs to /usr/include/gcc-7 include files in the target root, because immintrin.h from gcc 5 is not compatible with gcc 7.x. This applies for the targets where we build against a root from netbsd-8 (sparc64, powerpc, i386), and files/gcc-wrap gets a hack for this. * Pick up tweak for -latomic inclusion from rust-lang/rust#104220 and rust-lang/rust#104572 * Retain ability to do 32-bit NetBSD, by changing from 64 to 32 bit types in library/std/src/sys/unix/thread_parker/netbsd.rs. * I've struggled a bit to get the "openssl-src" build with -latomic where it's needed. I introduce "NetBSD-generic32" system type and use it for the NetBSD mipsel target. There is another attempt to do the same in the patch to vendor/openssl-sys/build/main.rs. * Bump bootstraps to 1.64.0, checksum updates. Upstream changes: Version 1.65.0 (2022-11-03) ========================== Language -------- - [Error on `as` casts of enums with `#[non_exhaustive]` variants] (rust-lang/rust#92744) - [Stabilize `let else`](rust-lang/rust#93628) - [Stabilize generic associated types (GATs)] (rust-lang/rust#96709) - [Add lints `let_underscore_drop`, `let_underscore_lock`, and `let_underscore_must_use` from Clippy] (rust-lang/rust#97739) - [Stabilize `break`ing from arbitrary labeled blocks ("label-break-value")] (rust-lang/rust#99332) - [Uninitialized integers, floats, and raw pointers are now considered immediate UB](rust-lang/rust#98919). Usage of `MaybeUninit` is the correct way to work with uninitialized memory. - [Stabilize raw-dylib for Windows x86_64, aarch64, and thumbv7a] (rust-lang/rust#99916) - [Do not allow `Drop` impl on foreign ADTs] (rust-lang/rust#99576) Compiler -------- - [Stabilize -Csplit-debuginfo on Linux] (rust-lang/rust#98051) - [Use niche-filling optimization even when multiple variants have data] (rust-lang/rust#94075) - [Associated type projections are now verified to be well-formed prior to resolving the underlying type] (rust-lang/rust#99217) - [Stringify non-shorthand visibility correctly] (rust-lang/rust#100350) - [Normalize struct field types when unsizing] (rust-lang/rust#101831) - [Update to LLVM 15](rust-lang/rust#99464) - [Fix aarch64 call abi to correctly zeroext when needed] (rust-lang/rust#97800) - [debuginfo: Generalize C++-like encoding for enums] (rust-lang/rust#98393) - [Add `special_module_name` lint] (rust-lang/rust#94467) - [Add support for generating unique profraw files by default when using `-C instrument-coverage`] (rust-lang/rust#100384) - [Allow dynamic linking for iOS/tvOS targets] (rust-lang/rust#100636) New targets: - [Add armv4t-none-eabi as a tier 3 target] (rust-lang/rust#100244) - [Add powerpc64-unknown-openbsd and riscv64-unknown-openbsd as tier 3 targets] (rust-lang/rust#101025) - Refer to Rust's [platform support page][platform-support-doc] for more information on Rust's tiered platform support. Libraries --------- - [Don't generate `PartialEq::ne` in derive(PartialEq)] (rust-lang/rust#98655) - [Windows RNG: Use `BCRYPT_RNG_ALG_HANDLE` by default] (rust-lang/rust#101325) - [Forbid mixing `System` with direct system allocator calls] (rust-lang/rust#101394) - [Document no support for writing to non-blocking stdio/stderr] (rust-lang/rust#101416) - [`std::layout::Layout` size must not overflow `isize::MAX` when rounded up to `align`](rust-lang/rust#95295) This also changes the safety conditions on `Layout::from_size_align_unchecked`. Stabilized APIs --------------- - [`std::backtrace::Backtrace`] (https://doc.rust-lang.org/stable/std/backtrace/struct.Backtrace.html) - [`Bound::as_ref`] (https://doc.rust-lang.org/stable/std/ops/enum.Bound.html#method.as_ref) - [`std::io::read_to_string`] (https://doc.rust-lang.org/stable/std/io/fn.read_to_string.html) - [`<*const T>::cast_mut`] (https://doc.rust-lang.org/stable/std/primitive.pointer.html#method.cast_mut) - [`<*mut T>::cast_const`] (https://doc.rust-lang.org/stable/std/primitive.pointer.html#method.cast_const) These APIs are now stable in const contexts: - [`<*const T>::offset_from`] (https://doc.rust-lang.org/stable/std/primitive.pointer.html#method.offset_from) - [`<*mut T>::offset_from`] (https://doc.rust-lang.org/stable/std/primitive.pointer.html#method.offset_from) Cargo ----- - [Apply GitHub fast path even for partial hashes] (rust-lang/cargo#10807) - [Do not add home bin path to PATH if it's already there] (rust-lang/cargo#11023) - [Take priority into account within the pending queue] (rust-lang/cargo#11032). This slightly optimizes job scheduling by Cargo, with typically small improvements on larger crate graph builds. Compatibility Notes ------------------- - [`std::layout::Layout` size must not overflow `isize::MAX` when rounded up to `align`] (rust-lang/rust#95295). This also changes the safety conditions on `Layout::from_size_align_unchecked`. - [`PollFn` now only implements `Unpin` if the closure is `Unpin`] (rust-lang/rust#102737). This is a possible breaking change if users were relying on the blanket unpin implementation. See discussion on the PR for details of why this change was made. - [Drop ExactSizeIterator impl from std::char::EscapeAscii] (rust-lang/rust#99880) This is a backwards-incompatible change to the standard library's surface area, but is unlikely to affect real world usage. - [Do not consider a single repeated lifetime eligible for elision in the return type] (rust-lang/rust#103450) This behavior was unintentionally changed in 1.64.0, and this release reverts that change by making this an error again. - [Reenable disabled early syntax gates as future-incompatibility lints] (rust-lang/rust#99935) - [Update the minimum external LLVM to 13] (rust-lang/rust#100460) - [Don't duplicate file descriptors into stdio fds] (rust-lang/rust#101426) - [Sunset RLS](rust-lang/rust#100863) - [Deny usage of `#![cfg_attr(..., crate_type = ...)]` to set the crate type] (rust-lang/rust#99784) This strengthens the forward compatibility lint deprecated_cfg_attr_crate_type_name to deny. - [`llvm-has-rust-patches` allows setting the build system to treat the LLVM as having Rust-specific patches] (rust-lang/rust#101072) This option may need to be set for distributions that are building Rust with a patched LLVM via `llvm-config`, not the built-in LLVM. 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 `x.sh` and `x.ps1` shell scripts] (rust-lang/rust#99992) - [compiletest: use target cfg instead of hard-coded tables] (rust-lang/rust#100260) - [Use object instead of LLVM for reading bitcode from rlibs] (rust-lang/rust#98100) - [Enable MIR inlining for optimized compilations] (rust-lang/rust#91743) This provides a 3-10% improvement in compiletimes for real world crates. See [perf results] (https://perf.rust-lang.org/compare.html?start=aedf78e56b2279cc869962feac5153b6ba7001ed&end=0075bb4fad68e64b6d1be06bf2db366c30bc75e1&stat=instructions:u).
This was referenced Dec 6, 2022
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Jan 23, 2023
Pkgsrc changes: * pkglint cleanups, bump bootstrap kits to 1.65.0. * New target: mipsel-unknown-netbsd, for cpu=mips32 with soft-float. * Managed to retain the build of aarch64_be, llvm needed a patch to avoid use of neon instructions in the BE case (llvm doesn't support use of neon in BE mode). Ref. patch to src/llvm-project/llvm/lib/Support/BLAKE3/blake3_impl.h. Also submitted upstream of LLVM to the BLAKE3 maintainers. * The minimum gcc version is now 7.x, and that includes the cross-compiler for the targets. For i386 this also needs to /usr/include/gcc-7 include files in the target root, because immintrin.h from gcc 5 is not compatible with gcc 7.x. This applies for the targets where we build against a root from netbsd-8 (sparc64, powerpc, i386), and files/gcc-wrap gets a hack for this. * Pick up tweak for -latomic inclusion from rust-lang/rust#104220 and rust-lang/rust#104572 * Retain ability to do 32-bit NetBSD, by changing from 64 to 32 bit types in library/std/src/sys/unix/thread_parker/netbsd.rs. * I've tried to get the "openssl-src" build with -latomic where it's needed. I've introduced the "NetBSD-generic32" system type and use it for the NetBSD mipsel target. There is another attempt to do the same in the patch to vendor/openssl-sys/build/main.rs. Upstream changes: Version 1.66.1 (2023-01-10) =========================== - Added validation of SSH host keys for git URLs in Cargo ([CVE-2022-46176](https://www.cve.org/CVERecord?id=CVE-2022-46176)) Version 1.66.0 (2022-12-15) =========================== Language -------- - [Permit specifying explicit discriminants on all `repr(Int)` enums](rust-lang/rust#95710) ```rust #[repr(u8)] enum Foo { A(u8) = 0, B(i8) = 1, C(bool) = 42, } ``` - [Allow transmutes between the same type differing only in lifetimes](rust-lang/rust#101520) - [Change constant evaluation errors from a deny-by-default lint to a hard error](rust-lang/rust#102091) - [Trigger `must_use` on `impl Trait` for supertraits](rust-lang/rust#102287) This makes `impl ExactSizeIterator` respect the existing `#[must_use]` annotation on `Iterator`. - [Allow `..X` and `..=X` in patterns](rust-lang/rust#102275) - [Uplift `clippy::for_loops_over_fallibles` lint into rustc](rust-lang/rust#99696) - [Stabilize `sym` operands in inline assembly](rust-lang/rust#103168) - [Update to Unicode 15](rust-lang/rust#101912) - [Opaque types no longer imply lifetime bounds](rust-lang/rust#95474) This is a soundness fix which may break code that was erroneously relying on this behavior. Compiler -------- - [Add armv5te-none-eabi and thumbv5te-none-eabi tier 3 targets](rust-lang/rust#101329) - Refer to Rust's [platform support page][platform-support-doc] for more information on Rust's tiered platform support. - [Add support for linking against macOS universal libraries](rust-lang/rust#98736) Libraries --------- - [Fix `#[derive(Default)]` on a generic `#[default]` enum adding unnecessary `Default` bounds](rust-lang/rust#101040) - [Update to Unicode 15](rust-lang/rust#101821) Stabilized APIs --------------- - [`proc_macro::Span::source_text`](https://doc.rust-lang.org/stable/proc_macro/struct.Span.html#method.source_text) - [`uX::{checked_add_signed, overflowing_add_signed, saturating_add_signed, wrapping_add_signed}`](https://doc.rust-lang.org/stable/std/primitive.u8.html#method.checked_add_signed) - [`iX::{checked_add_unsigned, overflowing_add_unsigned, saturating_add_unsigned, wrapping_add_unsigned}`](https://doc.rust-lang.org/stable/std/primitive.i8.html#method.checked_add_unsigned) - [`iX::{checked_sub_unsigned, overflowing_sub_unsigned, saturating_sub_unsigned, wrapping_sub_unsigned}`](https://doc.rust-lang.org/stable/std/primitive.i8.html#method.checked_sub_unsigned) - [`BTreeSet::{first, last, pop_first, pop_last}`](https://doc.rust-lang.org/stable/std/collections/struct.BTreeSet.html#method.first) - [`BTreeMap::{first_key_value, last_key_value, first_entry, last_entry, pop_first, pop_last}`](https://doc.rust-lang.org/stable/std/collections/struct.BTreeMap.html#method.first_key_value) - [Add `AsFd` implementations for stdio lock types on WASI.](rust-lang/rust#101768) - [`impl TryFrom<Vec<T>> for Box<[T; N]>`](https://doc.rust-lang.org/stable/std/boxed/struct.Box.html#impl-TryFrom%3CVec%3CT%2C%20Global%3E%3E-for-Box%3C%5BT%3B%20N%5D%2C%20Global%3E) - [`core::hint::black_box`](https://doc.rust-lang.org/stable/std/hint/fn.black_box.html) - [`Duration::try_from_secs_{f32,f64}`](https://doc.rust-lang.org/stable/std/time/struct.Duration.html#method.try_from_secs_f32) - [`Option::unzip`](https://doc.rust-lang.org/stable/std/option/enum.Option.html#method.unzip) - [`std::os::fd`](https://doc.rust-lang.org/stable/std/os/fd/index.html) Rustdoc ------- - [Add Rustdoc warning for invalid HTML tags in the documentation](rust-lang/rust#101720) Cargo ----- - [Added `cargo remove` to remove dependencies from Cargo.toml](https://doc.rust-lang.org/nightly/cargo/commands/cargo-remove.html) - [`cargo publish` now waits for the new version to be downloadable before exiting](rust-lang/cargo#11062) See [detailed release notes](https://github.com/rust-lang/cargo/blob/master/CHANGELOG.md#cargo-166-2022-12-15) for more. Compatibility Notes ------------------- - [Only apply `ProceduralMasquerade` hack to older versions of `rental`](rust-lang/rust#94063) - [Don't export `__heap_base` and `__data_end` on wasm32-wasi.](rust-lang/rust#102385) - [Don't export `__wasm_init_memory` on WebAssembly.](rust-lang/rust#102426) - [Only export `__tls_*` on wasm32-unknown-unknown.](rust-lang/rust#102440) - [Don't link to `libresolv` in libstd on Darwin](rust-lang/rust#102766) - [Update libstd's libc to 0.2.135 (to make `libstd` no longer pull in `libiconv.dylib` on Darwin)](rust-lang/rust#103277) - [Opaque types no longer imply lifetime bounds](rust-lang/rust#95474) This is a soundness fix which may break code that was erroneously relying on this behavior. - [Make `order_dependent_trait_objects` show up in future-breakage reports](rust-lang/rust#102635) - [Change std::process::Command spawning to default to inheriting the parent's signal mask](rust-lang/rust#101077) 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. - [Enable BOLT for LLVM compilation](rust-lang/rust#94381) - [Enable LTO for rustc_driver.so](rust-lang/rust#101403) Version 1.65.0 (2022-11-03) ========================== Language -------- - [Error on `as` casts of enums with `#[non_exhaustive]` variants] (rust-lang/rust#92744) - [Stabilize `let else`](rust-lang/rust#93628) - [Stabilize generic associated types (GATs)] (rust-lang/rust#96709) - [Add lints `let_underscore_drop`, `let_underscore_lock`, and `let_underscore_must_use` from Clippy] (rust-lang/rust#97739) - [Stabilize `break`ing from arbitrary labeled blocks ("label-break-value")] (rust-lang/rust#99332) - [Uninitialized integers, floats, and raw pointers are now considered immediate UB](rust-lang/rust#98919). Usage of `MaybeUninit` is the correct way to work with uninitialized memory. - [Stabilize raw-dylib for Windows x86_64, aarch64, and thumbv7a] (rust-lang/rust#99916) - [Do not allow `Drop` impl on foreign ADTs] (rust-lang/rust#99576) Compiler -------- - [Stabilize -Csplit-debuginfo on Linux] (rust-lang/rust#98051) - [Use niche-filling optimization even when multiple variants have data] (rust-lang/rust#94075) - [Associated type projections are now verified to be well-formed prior to resolving the underlying type] (rust-lang/rust#99217) - [Stringify non-shorthand visibility correctly] (rust-lang/rust#100350) - [Normalize struct field types when unsizing] (rust-lang/rust#101831) - [Update to LLVM 15](rust-lang/rust#99464) - [Fix aarch64 call abi to correctly zeroext when needed] (rust-lang/rust#97800) - [debuginfo: Generalize C++-like encoding for enums] (rust-lang/rust#98393) - [Add `special_module_name` lint] (rust-lang/rust#94467) - [Add support for generating unique profraw files by default when using `-C instrument-coverage`] (rust-lang/rust#100384) - [Allow dynamic linking for iOS/tvOS targets] (rust-lang/rust#100636) New targets: - [Add armv4t-none-eabi as a tier 3 target] (rust-lang/rust#100244) - [Add powerpc64-unknown-openbsd and riscv64-unknown-openbsd as tier 3 targets] (rust-lang/rust#101025) - Refer to Rust's [platform support page][platform-support-doc] for more information on Rust's tiered platform support. Libraries --------- - [Don't generate `PartialEq::ne` in derive(PartialEq)] (rust-lang/rust#98655) - [Windows RNG: Use `BCRYPT_RNG_ALG_HANDLE` by default] (rust-lang/rust#101325) - [Forbid mixing `System` with direct system allocator calls] (rust-lang/rust#101394) - [Document no support for writing to non-blocking stdio/stderr] (rust-lang/rust#101416) - [`std::layout::Layout` size must not overflow `isize::MAX` when rounded up to `align`](rust-lang/rust#95295) This also changes the safety conditions on `Layout::from_size_align_unchecked`. Stabilized APIs --------------- - [`std::backtrace::Backtrace`] (https://doc.rust-lang.org/stable/std/backtrace/struct.Backtrace.html) - [`Bound::as_ref`] (https://doc.rust-lang.org/stable/std/ops/enum.Bound.html#method.as_ref) - [`std::io::read_to_string`] (https://doc.rust-lang.org/stable/std/io/fn.read_to_string.html) - [`<*const T>::cast_mut`] (https://doc.rust-lang.org/stable/std/primitive.pointer.html#method.cast_mut) - [`<*mut T>::cast_const`] (https://doc.rust-lang.org/stable/std/primitive.pointer.html#method.cast_const) These APIs are now stable in const contexts: - [`<*const T>::offset_from`] (https://doc.rust-lang.org/stable/std/primitive.pointer.html#method.offset_from) - [`<*mut T>::offset_from`] (https://doc.rust-lang.org/stable/std/primitive.pointer.html#method.offset_from) Cargo ----- - [Apply GitHub fast path even for partial hashes] (rust-lang/cargo#10807) - [Do not add home bin path to PATH if it's already there] (rust-lang/cargo#11023) - [Take priority into account within the pending queue] (rust-lang/cargo#11032). This slightly optimizes job scheduling by Cargo, with typically small improvements on larger crate graph builds. Compatibility Notes ------------------- - [`std::layout::Layout` size must not overflow `isize::MAX` when rounded up to `align`] (rust-lang/rust#95295). This also changes the safety conditions on `Layout::from_size_align_unchecked`. - [`PollFn` now only implements `Unpin` if the closure is `Unpin`] (rust-lang/rust#102737). This is a possible breaking change if users were relying on the blanket unpin implementation. See discussion on the PR for details of why this change was made. - [Drop ExactSizeIterator impl from std::char::EscapeAscii] (rust-lang/rust#99880) This is a backwards-incompatible change to the standard library's surface area, but is unlikely to affect real world usage. - [Do not consider a single repeated lifetime eligible for elision in the return type] (rust-lang/rust#103450) This behavior was unintentionally changed in 1.64.0, and this release reverts that change by making this an error again. - [Reenable disabled early syntax gates as future-incompatibility lints] (rust-lang/rust#99935) - [Update the minimum external LLVM to 13] (rust-lang/rust#100460) - [Don't duplicate file descriptors into stdio fds] (rust-lang/rust#101426) - [Sunset RLS](rust-lang/rust#100863) - [Deny usage of `#![cfg_attr(..., crate_type = ...)]` to set the crate type] (rust-lang/rust#99784) This strengthens the forward compatibility lint deprecated_cfg_attr_crate_type_name to deny. - [`llvm-has-rust-patches` allows setting the build system to treat the LLVM as having Rust-specific patches] (rust-lang/rust#101072) This option may need to be set for distributions that are building Rust with a patched LLVM via `llvm-config`, not the built-in LLVM. 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 `x.sh` and `x.ps1` shell scripts] (rust-lang/rust#99992) - [compiletest: use target cfg instead of hard-coded tables] (rust-lang/rust#100260) - [Use object instead of LLVM for reading bitcode from rlibs] (rust-lang/rust#98100) - [Enable MIR inlining for optimized compilations] (rust-lang/rust#91743) This provides a 3-10% improvement in compiletimes for real world crates. See [perf results] (https://perf.rust-lang.org/compare.html?start=aedf78e56b2279cc869962feac5153b6ba7001ed&end=0075bb4fad68e64b6d1be06bf2db366c30bc75e1&stat=instructions:u).
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This PR resolves #97241.
This PR adds three lints from clippy--
let_underscore_drop,let_underscore_lock, andlet_underscore_must_use, which are meant to capture likely-incorrect uses oflet _ = ...bindings (in particular, doing this on a type with a non-trivialDropcauses theDropto occur immediately, instead of at the end of the scope. For a type likeMutexGuard, this effectively releases the lock immediately, which is almost certainly the wrong behavior)In porting the lints from clippy I had to copy over a bunch of utility functions from
clippy_utilthat these lints also relied upon. Is that the right approach?Note that I've set the
must_useanddroplints to Allow by default and setlockto Deny by default (this matches the same settings that clippy has). In talking with @estebank he informed me to do a Crater run (I am not sure what type of Crater run to request here--I think it's just "check only"?)On the linked issue, there's some discussion about using
must_useandDroptogether as a heuristic for when to warn--I did not implement this yet.r? @estebank