Check if call return type is visibly uninhabited when building MIR #93313

tmiasko · 2022-01-25T23:53:50Z

The main motivation behind the change is to expose information about diverging
calls to the generator transform and match the precision of drop range tracking
which already understands that call expressions with visibly uninhabited types
diverges.

This change should also accept strictly more programs than before. That is
programs that were previously rejected due to errors raised by control-flow
sensitive checks in a code that is no longer considered reachable.

Fixes #93161.

rust-highfive · 2022-01-25T23:53:53Z

r? @wesleywiser

(rust-highfive has picked a reviewer for you, use r? to override)

compiler/rustc_mir_build/src/build/expr/into.rs

compiler/rustc_session/src/options.rs

…jection, r=tmiasko Drop tracking: track borrows of projections Previous efforts to ignore partially consumed values meant we were also not considering borrows of a projection. This led to cases where we'd miss borrowed types which MIR expected to be there, leading to ICEs. This PR also includes the `-Zdrop-tracking` flag from rust-lang#93313. If that PR lands first, I'll rebase to drop the commit from this one. Fixes rust-lang#93648

wesleywiser · 2022-02-08T23:10:19Z

src/test/ui/generator/issue-93161.rs

@@ -32,7 +32,7 @@ fn never() -> Never {
 }

 async fn includes_never(crash: bool, x: u32) -> u32 {
-    let mut result = async { x * x }.await;
+    let result = async { x * x }.await;


This behavior change seems correct, but I wonder if we need to be concerned from a compatibility perspective?

To be clear: Wesley's assumption is that the unused mut lint started firing here (because the mutation of result falls after the call to never() below, and so that's why the PR author has removed the mut.

And Wesley's question is: Do we need to worry about this? Considering e.g. code that might have #![deny(unused_mut)], and now it starts seeing that as an error.

(My personal answer is that lints are allowed to change their behavior in this manner. I'm currently double-checking/asking around for examples from Rust's past.)

Additional discussion in https://rust-lang.zulipchat.com/#narrow/stream/213817-t-lang/topic/lints.2C.20flow-sensitivity.2C.20and.20stability

The lint side of things seems fine to me from compatibility perspective. It is
not unusual for us to adjust how lints work, and practical impact is limited by
cargo capping the lint level for dependencies.

The fact that we would now accept more programs seems more significant, since
it would be a breaking change to revert. Though, as far as I can see, we did in
fact accept those programs after #54125 landed, but have since regressed after
switching to MIR borrowck.

It also seems surprising that this mut would be unused, since result is mutated in later code -- in a regular function, we are not that smart wrt unused-mut warnings, or are we?

I was talking about this with @scottmcm a little while back and he found this example: https://play.rust-lang.org/?version=stable&mode=debug&edition=2021&gist=26220b66188903b1dd8f3325960f75af

That version compiles even though x is mutated, since the mutation comes after the panic. Although, for me making it let mut x doesn't raise an unused mut warning. Anyway, I think this shows prior art for being clever about things being mutated only in unreachable code, so this change seems to make things more uniform.

bors · 2022-02-15T05:13:26Z

☔ The latest upstream changes (presumably #93752) made this pull request unmergeable. Please resolve the merge conflicts.

bors · 2022-02-28T11:11:48Z

☔ The latest upstream changes (presumably #94427) made this pull request unmergeable. Please resolve the merge conflicts.

eholk · 2022-03-07T18:44:39Z

What's the status on this PR? Is it still waiting on a review, or are there changes that still need to be made?

tmiasko · 2022-03-08T16:35:36Z

It is waiting for review.

(I would be happy to review the change in other direction if this blocks drop tracking. That is, reduce precision on the typeck side and consider only call expressions with never type as diverging to match MIR building).

eholk · 2022-03-08T21:56:56Z

Sounds good. I just opened #94752, which pulls the fix I had added out of my earlier PR. That should be a little quicker to merge than this one, and it can coexist with this change, so I think it makes sense to go ahead and merge it. Once this change lands, we can consider reverting mine, although leaving it in wouldn't hurt anything either.

tmandry · 2022-03-17T17:02:13Z

Looks good, but I think it's missing a test for #93161 and the case of new programs being accepted (e.g. non-privately-uninhabited version of privately-uninhabited-mir-call.rs)

Another thing I want to check: What if the uninhabited type is #[non_exhaustive]? Seems like we should be conservative in that case.

tmiasko · 2022-03-17T17:36:14Z

Test for #93161 is already included as src/test/ui/generator/issue-93161.rs, and this pull request enables drop tracking for it (previously it did ICE with drop tracking enabled).

is_ty_uninhabited_from considers #[non_exhaustive] enums from other crates to be inhabited.

I added extra comments to privately-uninhabited-mir-call.rs to indicate that it contains both positive and negative test cases. The change removing mut from issue-93161.rs also showcases new code that is now being accepted.

tmandry · 2022-03-17T18:28:56Z

Oops, sorry for missing those.

is_ty_uninhabited_from considers #[non_exhaustive] enums from other crates to be inhabited.

Can you verify if there is a test that exercises this, and add one if not?

Otherwise looks good to me, but I'm checking with t-lang that we want to commit to this behavior. r=me with t-lang sign off.

tmiasko · 2022-03-17T18:44:04Z

is_ty_uninhabited_from considers #[non_exhaustive] enums from other crates to be inhabited.

Can you verify if there is a test that exercises this, and add one if not?

There are tests in context of exhaustiveness checking, for example src/test/ui/rfc-2008-non-exhaustive/uninhabited/match{,_same_crate}.rs

nikomatsakis · 2022-03-22T17:59:27Z

@tmiasko can you summarize the effects of this PR a bit more clearly? e.g., what is some code that does NOT compile today but which compiles after this PR? (and why)

rfcbot · 2022-04-19T18:47:21Z

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.

eholk · 2022-04-19T21:19:53Z

Since the FCP is passed, are there any more changes needed or can we go ahead and merge it?

@tmandry - You had an r=me earlier in the thread. Does this still look good to you?

tmandry · 2022-04-19T21:38:13Z

@bors r+

bors · 2022-04-19T21:38:14Z

📌 Commit 6f8a1ee has been approved by tmandry

Check if call return type is visibly uninhabited when building MIR The main motivation behind the change is to expose information about diverging calls to the generator transform and match the precision of drop range tracking which already understands that call expressions with visibly uninhabited types diverges. This change should also accept strictly more programs than before. That is programs that were previously rejected due to errors raised by control-flow sensitive checks in a code that is no longer considered reachable. Fixes rust-lang#93161.

Rollup of 6 pull requests Successful merges: - rust-lang#93313 (Check if call return type is visibly uninhabited when building MIR) - rust-lang#96160 (Miri/interpreter debugging tweaks) - rust-lang#96167 (Replace sys/unix/weak AtomicUsize with AtomicPtr) - rust-lang#96168 (Improve AddrParseError description) - rust-lang#96206 (Use sys::unix::locks::futex* on wasm+atomics.) - rust-lang#96234 (remove_dir_all_recursive: treat ELOOP the same as ENOTDIR) Failed merges: r? `@ghost` `@rustbot` modify labels: rollup

rustup rust-lang/rust#93313 somehow made it so that this does not have to be mutable any more...

RalfJung · 2022-04-20T21:48:17Z

src/test/ui/consts/const-eval/validate_uninhabited_zsts.32bit.stderr

   |
 LL | const BAR: [Empty; 3] = [unsafe { std::mem::transmute(()) }; 3];
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ type validation failed at [0]: encountered a value of uninhabited type Empty
-   |


This is a somewhat unfortunate reduction in test coverage for validity (we now error much earlier during evaluation)... ideally this would be adjusted to transmute to a type that is not 'visibly' uninhabited so that we still test the same code paths as before.

I did the same in a Miri test so that type definition can probably just be copied.

RalfJung · 2022-04-21T13:58:29Z

I guess the other question is, do we really want pub annotations to affect the operational behavior of a program? Or should pub only affect whether a program compiles, but never affect what the program does when it runs (and whether it has UB)?

Having the borrow checker take into account visibility makes sense to me, but somehow this ended up changing interpreter (Miri) behavior and that is worrying.

I guess what I am saying is: it is still definitely UB to create a value of any uninhabited type, public or otherwise.
I guess the difference due to this PR only arises in programs that do that, so at most it's a difference in which part of Miri throws the error?

eholk · 2022-04-21T17:47:31Z

@RalfJung - can you summarize how the behavior of Miri changed? Is it that what used to be a runtime error because a compiler error, or vice-versa? Or was it always a runtime error, but the error is different now?

If all that's changed is that Miri is reporting undefined behavior for different reasons, but the set of things that are UB is unchanged, that seems okay to me?

RalfJung · 2022-04-26T08:57:43Z

std::mem::transmute::<(), Void>(()) (with Void being a variantless enum) now fails with "called transmute on uninhabited type". That's because it doesn't even get a return place any more, so it has to abort very early -- it cannot even do the usual things transmute does, because those need a return place to put the result into.

But yeah, if there was a return place validation would then immediately return UB anyway. The testcases disabled validation to be able to exhibit some other code paths in Miri, and that's why the UB location changed, but with Miri's default flags only the UB message should change.

Kixunil · 2022-06-30T16:49:59Z

@tmiasko since this is linked from release notes, could you please edit the PR description to put emphasis on "visibly` and copy the explanation from #93313 (at least "Visibly uninhabited means that some public field has an uninhabited type." possibly with the example)? I believe it's significant information and not knowing got me worried at first. Had to scroll down to find out. Putting it in topmost comment would be much nicer.

Pkgsrc changes: * adapt patches (libc crate version bump) * no longer pass -I/usr/pkg/include through via gcc-wrap script. Attempt at fixing version skew with curl package vs. internal version of curl. * new checksums Upstream changes: Version 1.62.0 (2022-06-30) ========================== Language -------- - [Stabilize `#[derive(Default)]` on enums with a `#[default]` variant][94457] - [Stop validating some checks in dead code after functions with uninhabited return types][93313] - [Fix constants not getting dropped if part of a diverging expression][94775] - [Support unit struct/enum variant in destructuring assignment][95380] - [Remove mutable_borrow_reservation_conflict lint and allow the code pattern][96268] Compiler -------- - [linker: Stop using whole-archive on dependencies of dylibs][96436] - [Make `unaligned_references` lint deny-by-default][95372] This lint is also a future compatibility lint, and is expected to eventually become a hard error. - [Only add codegen backend to dep info if -Zbinary-dep-depinfo is used][93969] - [Reject `#[thread_local]` attribute on non-static items][95006] - [Add tier 3 `aarch64-pc-windows-gnullvm` and `x86_64-pc-windows-gnullvm` targets\*][94872] - [Implement a lint to warn about unused macro rules][96150] - [Promote `x86_64-unknown-none` target to Tier 2\*][95705] \* Refer to Rust's [platform support page][platform-support-doc] for more information on Rust's tiered platform support. Libraries --------- - [Move `CStr` to libcore, and `CString` to liballoc][94079] - [Windows: Use a pipe relay for chaining pipes][95841] - [Replace Linux Mutex and Condvar with futex based ones.][95035] - [Replace RwLock by a futex based one on Linux][95801] - [std: directly use pthread in UNIX parker implementation][96393] Stabilized APIs --------------- - [`bool::then_some`] - [`f32::total_cmp`] - [`f64::total_cmp`] - [`Stdin::lines`] - [`windows::CommandExt::raw_arg`] - [`impl<T: Default> Default for AssertUnwindSafe<T>`] - [`From<Rc<str>> for Rc<[u8]>`][rc-u8-from-str] - [`From<Arc<str>> for Arc<[u8]>`][arc-u8-from-str] - [`FusedIterator for EncodeWide`] - [RDM intrinsics on aarch64][stdarch/1285] Clippy ------ - [Create clippy lint against unexpectedly late drop for temporaries in match scrutinee expressions][94206] Cargo ----- - Added the `cargo add` command for adding dependencies to `Cargo.toml` from the command-line. [docs](https://doc.rust-lang.org/nightly/cargo/commands/cargo-add.html) - Package ID specs now support `name@version` syntax in addition to the previous `name:version` to align with the behavior in `cargo add` and other tools. `cargo install` and `cargo yank` also now support this syntax so the version does not need to passed as a separate flag. - The `git` and `registry` directories in Cargo's home directory (usually `~/.cargo`) are now marked as cache directories so that they are not included in backups or content indexing (on Windows). - Added automatic `@` argfile support, which will use "response files" if the command-line to `rustc` exceeds the operating system's limit. Compatibility Notes ------------------- - `cargo test` now passes `--target` to `rustdoc` if the specified target is the same as the host target. [#10594](rust-lang/cargo#10594) - [rustdoc: Remove .woff font files][96279] - [Enforce Copy bounds for repeat elements while considering lifetimes][95819] Internal Changes ---------------- - [Unify ReentrantMutex implementations across all platforms][96042] These changes provide no direct user facing benefits, but represent significant improvements to the internals and overall performance of rustc and related tools. [93313]: rust-lang/rust#93313 [93969]: rust-lang/rust#93969 [94079]: rust-lang/rust#94079 [94206]: rust-lang/rust#94206 [94457]: rust-lang/rust#94457 [94775]: rust-lang/rust#94775 [94872]: rust-lang/rust#94872 [95006]: rust-lang/rust#95006 [95035]: rust-lang/rust#95035 [95372]: rust-lang/rust#95372 [95380]: rust-lang/rust#95380 [95431]: rust-lang/rust#95431 [95705]: rust-lang/rust#95705 [95801]: rust-lang/rust#95801 [95819]: rust-lang/rust#95819 [95841]: rust-lang/rust#95841 [96042]: rust-lang/rust#96042 [96150]: rust-lang/rust#96150 [96268]: rust-lang/rust#96268 [96279]: rust-lang/rust#96279 [96393]: rust-lang/rust#96393 [96436]: rust-lang/rust#96436 [96557]: rust-lang/rust#96557 [`bool::then_some`]: https://doc.rust-lang.org/stable/std/primitive.bool.html#method.then_some [`f32::total_cmp`]: https://doc.rust-lang.org/stable/std/primitive.f32.html#method.total_cmp [`f64::total_cmp`]: https://doc.rust-lang.org/stable/std/primitive.f64.html#method.total_cmp [`Stdin::lines`]: https://doc.rust-lang.org/stable/std/io/struct.Stdin.html#method.lines [`impl<T: Default> Default for AssertUnwindSafe<T>`]: https://doc.rust-lang.org/stable/std/panic/struct.AssertUnwindSafe.html#impl-Default [rc-u8-from-str]: https://doc.rust-lang.org/stable/std/rc/struct.Rc.html#impl-From%3CRc%3Cstr%3E%3E [arc-u8-from-str]: https://doc.rust-lang.org/stable/std/sync/struct.Arc.html#impl-From%3CArc%3Cstr%3E%3E [stdarch/1285]: rust-lang/stdarch#1285 [`windows::CommandExt::raw_arg`]: https://doc.rust-lang.org/stable/std/os/windows/process/trait.CommandExt.html#tymethod.raw_arg [`FusedIterator for EncodeWide`]: https://doc.rust-lang.org/stable/std/os/windows/ffi/struct.EncodeWide.html#impl-FusedIterator

Pkgsrc changes: * Bump required GCC to 7 (same as LLVM) to avoid ABI issues Fixes native i386 and powerpc 8.x build w/pkgsrc LLVM 14 * Bump available bootstraps to 1.61.0. * Also unlimit stacksize * Sync patches over from wip/rust * Adjust line number in patches which had non-zero offsets. * no longer pass -I/usr/pkg/include through via gcc-wrap script when building natively. Attempt at fixing version skew with curl package vs. internal version of curl (may not work...) * The NetBSD bootstraps now use .xz compression. * Use mk/atomic64.mk. Still have conditional for libatomic-links. * Default to using the internal LLVM when cross-building. Upstream changes: Version 1.62.1 (2022-07-19) ========================== Rust 1.62.1 addresses a few recent regressions in the compiler and standard library, and also mitigates a CPU vulnerability on Intel SGX. * [The compiler fixed unsound function coercions involving `impl Trait` return types.][98608] * [The compiler fixed an incremental compilation bug with `async fn` lifetimes.][98890] * [Windows added a fallback for overlapped I/O in synchronous reads and writes.][98950] * [The `x86_64-fortanix-unknown-sgx` target added a mitigation for the MMIO stale data vulnerability][98126], advisory [INTEL-SA-00615]. [98608]: rust-lang/rust#98608 [98890]: rust-lang/rust#98890 [98950]: rust-lang/rust#98950 [98126]: rust-lang/rust#98126 [INTEL-SA-00615]: https://www.intel.com/content/www/us/en/security-center/advisory/intel-sa-00615.html Version 1.62.0 (2022-06-30) ========================== Language -------- - [Stabilize `#[derive(Default)]` on enums with a `#[default]` variant][94457] - [Stop validating some checks in dead code after functions with uninhabited return types][93313] - [Fix constants not getting dropped if part of a diverging expression][94775] - [Support unit struct/enum variant in destructuring assignment][95380] - [Remove mutable_borrow_reservation_conflict lint and allow the code pattern][96268] Compiler -------- - [linker: Stop using whole-archive on dependencies of dylibs][96436] - [Make `unaligned_references` lint deny-by-default][95372] This lint is also a future compatibility lint, and is expected to eventually become a hard error. - [Only add codegen backend to dep info if -Zbinary-dep-depinfo is used][93969] - [Reject `#[thread_local]` attribute on non-static items][95006] - [Add tier 3 `aarch64-pc-windows-gnullvm` and `x86_64-pc-windows-gnullvm` targets\*][94872] - [Implement a lint to warn about unused macro rules][96150] - [Promote `x86_64-unknown-none` target to Tier 2\*][95705] \* Refer to Rust's [platform support page][platform-support-doc] for more information on Rust's tiered platform support. Libraries --------- - [Move `CStr` to libcore, and `CString` to liballoc][94079] - [Windows: Use a pipe relay for chaining pipes][95841] - [Replace Linux Mutex and Condvar with futex based ones.][95035] - [Replace RwLock by a futex based one on Linux][95801] - [std: directly use pthread in UNIX parker implementation][96393] Stabilized APIs --------------- - [`bool::then_some`] - [`f32::total_cmp`] - [`f64::total_cmp`] - [`Stdin::lines`] - [`windows::CommandExt::raw_arg`] - [`impl<T: Default> Default for AssertUnwindSafe<T>`] - [`From<Rc<str>> for Rc<[u8]>`][rc-u8-from-str] - [`From<Arc<str>> for Arc<[u8]>`][arc-u8-from-str] - [`FusedIterator for EncodeWide`] - [RDM intrinsics on aarch64][stdarch/1285] Clippy ------ - [Create clippy lint against unexpectedly late drop for temporaries in match scrutinee expressions][94206] Cargo ----- - Added the `cargo add` command for adding dependencies to `Cargo.toml` from the command-line. [docs](https://doc.rust-lang.org/nightly/cargo/commands/cargo-add.html) - Package ID specs now support `name@version` syntax in addition to the previous `name:version` to align with the behavior in `cargo add` and other tools. `cargo install` and `cargo yank` also now support this syntax so the version does not need to passed as a separate flag. - The `git` and `registry` directories in Cargo's home directory (usually `~/.cargo`) are now marked as cache directories so that they are not included in backups or content indexing (on Windows). - Added automatic `@` argfile support, which will use "response files" if the command-line to `rustc` exceeds the operating system's limit. Compatibility Notes ------------------- - `cargo test` now passes `--target` to `rustdoc` if the specified target is the same as the host target. [#10594](rust-lang/cargo#10594) - [rustdoc: Remove .woff font files][96279] - [Enforce Copy bounds for repeat elements while considering lifetimes][95819] Internal Changes ---------------- - [Unify ReentrantMutex implementations across all platforms][96042] These changes provide no direct user facing benefits, but represent significant improvements to the internals and overall performance of rustc and related tools. [93313]: rust-lang/rust#93313 [93969]: rust-lang/rust#93969 [94079]: rust-lang/rust#94079 [94206]: rust-lang/rust#94206 [94457]: rust-lang/rust#94457 [94775]: rust-lang/rust#94775 [94872]: rust-lang/rust#94872 [95006]: rust-lang/rust#95006 [95035]: rust-lang/rust#95035 [95372]: rust-lang/rust#95372 [95380]: rust-lang/rust#95380 [95431]: rust-lang/rust#95431 [95705]: rust-lang/rust#95705 [95801]: rust-lang/rust#95801 [95819]: rust-lang/rust#95819 [95841]: rust-lang/rust#95841 [96042]: rust-lang/rust#96042 [96150]: rust-lang/rust#96150 [96268]: rust-lang/rust#96268 [96279]: rust-lang/rust#96279 [96393]: rust-lang/rust#96393 [96436]: rust-lang/rust#96436 [96557]: rust-lang/rust#96557 [`bool::then_some`]: https://doc.rust-lang.org/stable/std/primitive.bool.html#method.then_some [`f32::total_cmp`]: https://doc.rust-lang.org/stable/std/primitive.f32.html#method.total_cmp [`f64::total_cmp`]: https://doc.rust-lang.org/stable/std/primitive.f64.html#method.total_cmp [`Stdin::lines`]: https://doc.rust-lang.org/stable/std/io/struct.Stdin.html#method.lines [`impl<T: Default> Default for AssertUnwindSafe<T>`]: https://doc.rust-lang.org/stable/std/panic/struct.AssertUnwindSafe.html#impl-Default [rc-u8-from-str]: https://doc.rust-lang.org/stable/std/rc/struct.Rc.html#impl-From%3CRc%3Cstr%3E%3E [arc-u8-from-str]: https://doc.rust-lang.org/stable/std/sync/struct.Arc.html#impl-From%3CArc%3Cstr%3E%3E [stdarch/1285]: rust-lang/stdarch#1285 [`windows::CommandExt::raw_arg`]: https://doc.rust-lang.org/stable/std/os/windows/process/trait.CommandExt.html#tymethod.raw_arg [`FusedIterator for EncodeWide`]: https://doc.rust-lang.org/stable/std/os/windows/ffi/struct.EncodeWide.html#impl-FusedIterator Version 1.61.0 (2022-05-19) ========================== Language -------- - [`const fn` signatures can now include generic trait bounds][93827] - [`const fn` signatures can now use `impl Trait` in argument and return position][93827] - [Function pointers can now be created, cast, and passed around in a `const fn`][93827] - [Recursive calls can now set the value of a function's opaque `impl Trait` return type][94081] Compiler -------- - [Linking modifier syntax in `#[link]` attributes and on the command line, as well as the `whole-archive` modifier specifically, are now supported][93901] - [The `char` type is now described as UTF-32 in debuginfo][89887] - The [`#[target_feature]`][target_feature] attribute [can now be used with aarch64 features][90621] - X86 [`#[target_feature = "adx"]` is now stable][93745] Libraries --------- - [`ManuallyDrop<T>` is now documented to have the same layout as `T`][88375] - [`#[ignore = "#"]` messages are printed when running tests][92714] - [Consistently show absent stdio handles on Windows as NULL handles][93263] - [Make `std::io::stdio::lock()` return `'static` handles.][93965] Previously, the creation of locked handles to stdin/stdout/stderr would borrow the handles being locked, which prevented writing `let out = std::io::stdout().lock();` because `out` would outlive the return value of `stdout()`. Such code now works, eliminating a common pitfall that affected many Rust users. - [`Vec::from_raw_parts` is now less restrictive about its inputs][95016] - [`std::thread::available_parallelism` now takes cgroup quotas into account.][92697] Since `available_parallelism` is often used to create a thread pool for parallel computation, which may be CPU-bound for performance, `available_parallelism` will return a value consistent with the ability to use that many threads continuously, if possible. For instance, in a container with 8 virtual CPUs but quotas only allowing for 50% usage, `available_parallelism` will return 4. Stabilized APIs --------------- - [`Pin::static_mut`] - [`Pin::static_ref`] - [`Vec::retain_mut`] - [`VecDeque::retain_mut`] - [`Write` for `Cursor<[u8; N]>`][cursor-write-array] - [`std::os::unix::net::SocketAddr::from_pathname`] - [`std::process::ExitCode`] and [`std::process::Termination`]. The stabilization of these two API s now makes it possible for programs to return errors from `main` with custom exit codes. - [`std::thread::JoinHandle::is_finished`] These APIs are now usable in const contexts: - [`<*const T>::offset` and `<*mut T>::offset`][ptr-offset] - [`<*const T>::wrapping_offset` and `<*mut T>::wrapping_offset`] [ptr-wrapping_offset] - [`<*const T>::add` and `<*mut T>::add`][ptr-add] - [`<*const T>::sub` and `<*mut T>::sub`][ptr-sub] - [`<*const T>::wrapping_add` and `<*mut T>::wrapping_add`][ptr-wrapping_add] - [`<*const T>::wrapping_sub` and `<*mut T>::wrapping_sub`][ptr-wrapping_sub] - [`<[T]>::as_mut_ptr`][slice-as_mut_ptr] - [`<[T]>::as_ptr_range`][slice-as_ptr_range] - [`<[T]>::as_mut_ptr_range`][slice-as_mut_ptr_range] Cargo ----- No feature changes, but see compatibility notes. Compatibility Notes ------------------- - Previously native static libraries were linked as `whole-archive` in some cases, but now rustc tries not to use `whole-archive` unless explicitly requested. This [change][93901] may result in linking errors in some cases. To fix such errors, native libraries linked from the command line, build scripts, or [`#[link]` attributes][link-attr] need to - (more common) either be reordered to respect dependencies between them (if `a` depends on `b` then `a` should go first and `b` second) - (less common) or be updated to use the [`+whole-archive`] modifier. - [Catching a second unwind from FFI code while cleaning up from a Rust panic now causes the process to abort][92911] - [Proc macros no longer see `ident` matchers wrapped in groups][92472] - [The number of `#` in `r#` raw string literals is now required to be less than 256][95251] - [When checking that a dyn type satisfies a trait bound, supertrait bounds are now enforced][92285] - [`cargo vendor` now only accepts one value for each `--sync` flag] [cargo/10448] - [`cfg` predicates in `all()` and `any()` are always evaluated to detect errors, instead of short-circuiting.][94295] The compatibility considerations here arise in nightly-only code that used the short-circuiting behavior of `all` to write something like `cfg(all(feature = "nightly", syntax-requiring-nightly))`, which will now fail to compile. Instead, use either `cfg_attr(feature = "nightly", ...)` or nested uses of `cfg`. - [bootstrap: static-libstdcpp is now enabled by default, and can now be disabled when llvm-tools is enabled][94832] Internal Changes ---------------- These changes provide no direct user facing benefits, but represent significant improvements to the internals and overall performance of rustc and related tools. - [debuginfo: Refactor debuginfo generation for types][94261] - [Remove the everybody loops pass][93913] [88375]: rust-lang/rust#88375 [89887]: rust-lang/rust#89887 [90621]: rust-lang/rust#90621 [92285]: rust-lang/rust#92285 [92472]: rust-lang/rust#92472 [92697]: rust-lang/rust#92697 [92714]: rust-lang/rust#92714 [92911]: rust-lang/rust#92911 [93263]: rust-lang/rust#93263 [93745]: rust-lang/rust#93745 [93827]: rust-lang/rust#93827 [93901]: rust-lang/rust#93901 [93913]: rust-lang/rust#93913 [93965]: rust-lang/rust#93965 [94081]: rust-lang/rust#94081 [94261]: rust-lang/rust#94261 [94295]: rust-lang/rust#94295 [94832]: rust-lang/rust#94832 [95016]: rust-lang/rust#95016 [95251]: rust-lang/rust#95251 [`+whole-archive`]: https://doc.rust-lang.org/stable/rustc/command-line-arguments.html#linking-modifiers-whole-archive [`Pin::static_mut`]: https://doc.rust-lang.org/stable/std/pin/struct.Pin.html#method.static_mut [`Pin::static_ref`]: https://doc.rust-lang.org/stable/std/pin/struct.Pin.html#method.static_ref [`Vec::retain_mut`]: https://doc.rust-lang.org/stable/std/vec/struct.Vec.html#method.retain_mut [`VecDeque::retain_mut`]: https://doc.rust-lang.org/stable/std/collections/struct.VecDeque.html#method.retain_mut [`std::os::unix::net::SocketAddr::from_pathname`]: https://doc.rust-lang.org/stable/std/os/unix/net/struct.SocketAddr.html#method.from_pathname [`std::process::ExitCode`]: https://doc.rust-lang.org/stable/std/process/struct.ExitCode.html [`std::process::Termination`]: https://doc.rust-lang.org/stable/std/process/trait.Termination.html [`std::thread::JoinHandle::is_finished`]: https://doc.rust-lang.org/stable/std/thread/struct.JoinHandle.html#method.is_finished [cargo/10448]: rust-lang/cargo#10448 [cursor-write-array]: https://doc.rust-lang.org/stable/std/io/struct.Cursor.html#impl-Write-4 [link-attr]: https://doc.rust-lang.org/stable/reference/items/external-blocks.html#the-link-attribute [ptr-add]: https://doc.rust-lang.org/stable/std/primitive.pointer.html#method.add [ptr-offset]: https://doc.rust-lang.org/stable/std/primitive.pointer.html#method.offset [ptr-sub]: https://doc.rust-lang.org/stable/std/primitive.pointer.html#method.sub [ptr-wrapping_add]: https://doc.rust-lang.org/stable/std/primitive.pointer.html#method.wrapping_add [ptr-wrapping_offset]: https://doc.rust-lang.org/stable/std/primitive.pointer.html#method.wrapping_offset [ptr-wrapping_sub]: https://doc.rust-lang.org/stable/std/primitive.pointer.html#method.wrapping_sub [slice-as_mut_ptr]: https://doc.rust-lang.org/stable/std/primitive.slice.html#method.as_mut_ptr [slice-as_mut_ptr_range]: https://doc.rust-lang.org/stable/std/primitive.slice.html#method.as_mut_ptr_range [slice-as_ptr_range]: https://doc.rust-lang.org/stable/std/primitive.slice.html#method.as_ptr_range [target_feature]: https://doc.rust-lang.org/reference/attributes/codegen.html#the-target_feature-attribute

rust-highfive assigned wesleywiser Jan 25, 2022

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tmiasko mentioned this pull request Jan 26, 2022

Fix drop tracking ICEs and re-enable generator drop tracking #93180

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Drop tracking: track borrows of projections #93751

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Generator drop tracking: improve break and continue handling #93752

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tmiasko force-pushed the uninhabited branch from 5ab2f41 to 063d1ef Compare February 15, 2022 08:06

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[Drop Tracking] Allow uninhabited types in generator interiors #94752

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Rollup of 6 pull requests #96241

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Rollup of 6 pull requests #96253

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rustup rust-lang/miri#2078

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Auto merge of #2078 - RalfJung:rustup, r=RalfJung

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rustup rust-lang/rust#93313 somehow made it so that this does not have to be mutable any more...

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Auto merge of #2078 - RalfJung:rustup, r=RalfJung

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rustup rust-lang/rust#93313 somehow made it so that this does not have to be mutable any more...

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update Miri #96254

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Update validate_uninhabited_zsts.rs test after MIR building changes #96272

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Update RELEASES.md #98734

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Check if call return type is visibly uninhabited when building MIR #93313

Check if call return type is visibly uninhabited when building MIR #93313

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Check if call return type is visibly uninhabited when building MIR #93313

Check if call return type is visibly uninhabited when building MIR #93313

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