Lint on some incorrect uses of mem::zeroed / mem::uninitialized #63346

RalfJung · 2019-08-07T08:14:24Z

Cc #62825 and https://internals.rust-lang.org/t/make-mem-uninitialized-and-mem-zeroed-panic-for-some-types-where-0-is-a-niche/10605

This does not yet handle NonNull/NonZero*, but it is a start.

I also improved some doc issues I hit on the way, and added a useful helper to TyS.

EDIT: I added the relnotes label mostly as a proposal -- I think this is worth mentioning, but leave the decision up to the release team.

rust-highfive · 2019-08-07T08:14:28Z

r? @varkor

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RalfJung · 2019-08-07T08:15:33Z

src/librustc_lint/builtin.rs

@@ -1862,3 +1862,90 @@ impl EarlyLintPass for IncompleteFeatures {
            });
    }
 }
+
+declare_lint! {
+    pub INVALID_VALUE,


I used the "validity" terminology here. Does that seem okay?

src/librustc/ty/mod.rs

RalfJung · 2019-08-07T09:54:17Z

@bjorn3 deleted a comment

Please don't do that. GH has a "hide comment" feature and "resolve discussion" which helps not to clutter the main thread. But don't delete comments after other people replied, and really don't delete other people's comments.

bjorn3 · 2019-08-07T09:58:01Z

But don't delete comments after other people replied, and really don't delete other people's comments.

I though I removed it before someone commented. I think your comment got deleted because I deleted mine.

GH has a "hide comment" feature

Will use it in the future.

jethrogb · 2019-08-07T19:56:58Z

src/librustc_lint/builtin.rs

+                // FIXME: *Only for `mem::uninitialized`*, we could also warn for `bool`,
+                //        `char`, and any multivariant enum.
+                // Conservative fallback.
+                _ => true,


Can you check for types with rustc_layout_scalar_valid_range_start here?

In the future this should probably check for that attribute, yes.

RalfJung · 2019-08-08T18:06:25Z

Would be nice if this could land before beta cutoff (Tuesday), so that we get these lints on stable.

eddyb · 2019-08-09T13:13:33Z

@bors r+

bors · 2019-08-09T13:13:34Z

📌 Commit 6c7d84d has been approved by eddyb

Lint on some incorrect uses of mem::zeroed / mem::uninitialized Cc rust-lang#62825 and https://internals.rust-lang.org/t/make-mem-uninitialized-and-mem-zeroed-panic-for-some-types-where-0-is-a-niche/10605 This does not yet handle `NonNull`/`NonZero*`, but it is a start. I also improved some doc issues I hit on the way, and added a useful helper to `TyS`.

RalfJung · 2019-08-09T20:03:54Z

Looks like this breaks clippy tests.

@bors r-

RalfJung · 2019-08-09T20:22:22Z

Blocked on clippy PR: rust-lang/rust-clippy#4368

deprecate invalid_ref lint This fixes the `invalid_ref` lint test to no longer fail when rust-lang/rust#63346 lands. I also fixed the lint itself, because its wording made no sense: there is no "reference to zeroed/uninitialized memory" here. changelog: none

RalfJung · 2019-08-11T12:50:33Z

@bors p=1

Would be good to get that lint into the beta together with #63343

Lint on some incorrect uses of mem::zeroed / mem::uninitialized Cc rust-lang#62825 and https://internals.rust-lang.org/t/make-mem-uninitialized-and-mem-zeroed-panic-for-some-types-where-0-is-a-niche/10605 This does not yet handle `NonNull`/`NonZero*`, but it is a start. I also improved some doc issues I hit on the way, and added a useful helper to `TyS`. EDIT: I added the relnotes label mostly as a proposal -- I think this is worth mentioning, but leave the decision up to the release team.

@ghost

Rollup of 8 pull requests Successful merges: - #61969 (Add #[repr(transparent)] for several types) - #62108 (Use sharded maps for queries) - #63149 (resolve: Populate external modules in more automatic and lazy way) - #63346 (Lint on some incorrect uses of mem::zeroed / mem::uninitialized) - #63433 (Miri shouldn't look at types) - #63440 (rename RUST_CTFE_BACKTRACE to RUSTC_CTFE_BACKTRACE) - #63442 (Add an example to show how to insert item to a sorted vec) - #63459 (syntax: account for CVarArgs being in the argument list.) Failed merges: r? @ghost

bors · 2019-08-11T19:15:17Z

⌛ Testing commit 0930747 with merge a8f340856b1b16c2d3ce9bb2c40b604947cf7ea6...

Lint on some incorrect uses of mem::zeroed / mem::uninitialized Cc rust-lang#62825 and https://internals.rust-lang.org/t/make-mem-uninitialized-and-mem-zeroed-panic-for-some-types-where-0-is-a-niche/10605 This does not yet handle `NonNull`/`NonZero*`, but it is a start. I also improved some doc issues I hit on the way, and added a useful helper to `TyS`. EDIT: I added the relnotes label mostly as a proposal -- I think this is worth mentioning, but leave the decision up to the release team.

Mark-Simulacrum · 2019-08-11T19:19:28Z

@bors retry prioritizing rollup that includes this PR

@ghost

Rollup of 8 pull requests Successful merges: - #61969 (Add #[repr(transparent)] for several types) - #63346 (Lint on some incorrect uses of mem::zeroed / mem::uninitialized) - #63433 (Miri shouldn't look at types) - #63440 (rename RUST_CTFE_BACKTRACE to RUSTC_CTFE_BACKTRACE) - #63441 (Derive Debug for CrateInfo) - #63442 (Add an example to show how to insert item to a sorted vec) - #63453 (rustdoc: general cleanup) - #63464 (Copy ty::Instance instead of passing by reference) Failed merges: r? @ghost

bors · 2019-08-11T22:52:52Z

⌛ Testing commit 0930747 with merge 00ee1b4...

Pkgsrc changes: * Adapt to the move of the implementation of random numbers. * Remove patch which is no longer relevant (Signals.inc) * Cross-build currently fails due to the still unresolved rust-lang/rust#62558, so bootstrap kits for 1.38.0 have to be built natively, and will follow shortly. * Bump bootstrap requirements to 1.37.0 except for armv7-unknown-netbsd-eabihf which I've neither managed to cross-build nor build natively. Upstream changes: Version 1.38.0 (2019-09-26) ========================== Language -------- - [The `#[global_allocator]` attribute can now be used in submodules.][62735] - [The `#[deprecated]` attribute can now be used on macros.][62042] Compiler -------- - [Added pipelined compilation support to `rustc`.][62766] This will improve compilation times in some cases. For further information please refer to the [_"Evaluating pipelined rustc compilation"_][pipeline-internals] thread. - [Added tier 3\* support for the `aarch64-uwp-windows-msvc`, `i686-uwp-windows-gnu`, `i686-uwp-windows-msvc`, `x86_64-uwp-windows-gnu`, and `x86_64-uwp-windows-msvc` targets.][60260] - [Added tier 3 support for the `armv7-unknown-linux-gnueabi` and `armv7-unknown-linux-musleabi` targets.][63107] - [Added tier 3 support for the `hexagon-unknown-linux-musl` target.][62814] - [Added tier 3 support for the `riscv32i-unknown-none-elf` target.][62784] \* Refer to Rust's [platform support page][forge-platform-support] for more information on Rust's tiered platform support. Libraries --------- - [`ascii::EscapeDefault` now implements `Clone` and `Display`.][63421] - [Derive macros for prelude traits (e.g. `Clone`, `Debug`, `Hash`) are now available at the same path as the trait.][63056] (e.g. The `Clone` derive macro is available at `std::clone::Clone`). This also makes all built-in macros available in `std`/`core` root. e.g. `std::include_bytes!`. - [`str::Chars` now implements `Debug`.][63000] - [`slice::{concat, connect, join}` now accepts `&[T]` in addition to `&T`.][62528] - [`*const T` and `*mut T` now implement `marker::Unpin`.][62583] - [`Arc<[T]>` and `Rc<[T]>` now implement `FromIterator<T>`.][61953] - [Added euclidean remainder and division operations (`div_euclid`, `rem_euclid`) to all numeric primitives.][61884] Additionally `checked`, `overflowing`, and `wrapping` versions are available for all integer primitives. - [`thread::AccessError` now implements `Clone`, `Copy`, `Eq`, `Error`, and `PartialEq`.][61491] - [`iter::{StepBy, Peekable, Take}` now implement `DoubleEndedIterator`.][61457] Stabilized APIs --------------- - [`<*const T>::cast`] - [`<*mut T>::cast`] - [`Duration::as_secs_f32`] - [`Duration::as_secs_f64`] - [`Duration::div_duration_f32`] - [`Duration::div_duration_f64`] - [`Duration::div_f32`] - [`Duration::div_f64`] - [`Duration::from_secs_f32`] - [`Duration::from_secs_f64`] - [`Duration::mul_f32`] - [`Duration::mul_f64`] - [`any::type_name`] Cargo ----- - [Added pipelined compilation support to `cargo`.][cargo/7143] - [You can now pass the `--features` option multiple times to enable multiple features.][cargo/7084] Misc ---- - [`rustc` will now warn about some incorrect uses of `mem::{uninitialized, zeroed}` that are known to cause undefined behaviour.][63346] Compatibility Notes ------------------- - Unfortunately the [`x86_64-unknown-uefi` platform can not be built][62785] with rustc 1.39.0. - The [`armv7-unknown-linux-gnueabihf` platform is also known to have issues][62896] for certain crates such as libc. [60260]: rust-lang/rust#60260 [61457]: rust-lang/rust#61457 [61491]: rust-lang/rust#61491 [61884]: rust-lang/rust#61884 [61953]: rust-lang/rust#61953 [62042]: rust-lang/rust#62042 [62528]: rust-lang/rust#62528 [62583]: rust-lang/rust#62583 [62735]: rust-lang/rust#62735 [62766]: rust-lang/rust#62766 [62784]: rust-lang/rust#62784 [62785]: rust-lang/rust#62785 [62814]: rust-lang/rust#62814 [62896]: rust-lang/rust#62896 [63000]: rust-lang/rust#63000 [63056]: rust-lang/rust#63056 [63107]: rust-lang/rust#63107 [63346]: rust-lang/rust#63346 [63421]: rust-lang/rust#63421 [cargo/7084]: rust-lang/cargo#7084 [cargo/7143]: rust-lang/cargo#7143 [`<*const T>::cast`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.cast [`<*mut T>::cast`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.cast [`Duration::as_secs_f32`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.as_secs_f32 [`Duration::as_secs_f64`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.as_secs_f64 [`Duration::div_duration_f32`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.div_duration_f32 [`Duration::div_duration_f64`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.div_duration_f64 [`Duration::div_f32`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.div_f32 [`Duration::div_f64`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.div_f64 [`Duration::from_secs_f32`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.from_secs_f32 [`Duration::from_secs_f64`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.from_secs_f64 [`Duration::mul_f32`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.mul_f32 [`Duration::mul_f64`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.mul_f64 [`any::type_name`]: https://doc.rust-lang.org/std/any/fn.type_name.html [forge-platform-support]: https://forge.rust-lang.org/platform-support.html [pipeline-internals]: https://internals.rust-lang.org/t/evaluating-pipelined-rustc-compilation/10199

implement zeroed and uninitialized with MaybeUninit This is the second attempt of doing such a change (first PR: rust-lang#62150). The last change [got reverted](rust-lang#63343) because it [caused](rust-lang#62825) some [issues](rust-lang#52898 (comment)) in [code that incorrectly used these functions](AltF02/x11-rs#99). Since then, the [problematic code has been fixed](AltF02/x11-rs#101), and rustc [gained a lint](rust-lang#63346) that is able to detect many misuses of these functions statically and a [dynamic check that panics](rust-lang#66059) instead of causing UB for some incorrect uses. Fixes rust-lang#62825

rust-highfive assigned varkor Aug 7, 2019

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RalfJung commented Aug 7, 2019

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This was referenced Aug 7, 2019

re-land #62150 (Implement mem::{zeroed,uninitialized} in terms of MaybeUninit) #62825

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Separate DefIds for variants and their constructors #59382

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petrochenkov reviewed Aug 7, 2019

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eddyb approved these changes Aug 9, 2019

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Centril mentioned this pull request Aug 9, 2019

Rollup of 5 pull requests #63412

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bors added S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. and removed S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. labels Aug 9, 2019

RalfJung mentioned this pull request Aug 9, 2019

deprecate invalid_ref lint rust-lang/rust-clippy#4368

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Mark-Simulacrum mentioned this pull request Aug 11, 2019

Rollup of 8 pull requests #63465

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Mark-Simulacrum mentioned this pull request Aug 11, 2019

Rollup of 8 pull requests #63471

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varkor assigned eddyb and unassigned varkor Aug 11, 2019

bors merged commit 0930747 into rust-lang:master Aug 11, 2019

RalfJung deleted the zeroed-lint branch August 12, 2019 06:30

RalfJung mentioned this pull request Aug 26, 2019

causes UB by calling mem::zeroed on any type Diggsey/rust-field-offset#2

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RalfJung mentioned this pull request Mar 11, 2020

implement zeroed and uninitialized with MaybeUninit #69922

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RalfJung mentioned this pull request Jun 21, 2020

attempted to leave type (enum) uninitialized, which is invalid #73573

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Lint on some incorrect uses of mem::zeroed / mem::uninitialized #63346

Lint on some incorrect uses of mem::zeroed / mem::uninitialized #63346

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Lint on some incorrect uses of mem::zeroed / mem::uninitialized #63346

Lint on some incorrect uses of mem::zeroed / mem::uninitialized #63346

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