Tweak `FlatPat::new` to avoid a temporarily-invalid state
It was somewhat confusing that the old constructor would create a `FlatPat` in a (possibly) non-simplified state, and then simplify its contents in-place.
So instead we now create its fields as local variables, perform simplification, and then create the struct afterwards.
This doesn't affect correctness, but is less confusing.
---
I've also included some semi-related comments that I made while trying to navigate this code.
core: VaArgSafe is an unsafe trait
`T: VaArgSafe` is relied on for soundness. Safe impls promise nothing. Therefore this must be an unsafe trait. Slightly pedantic, as only core can impl this, but we *could* choose to unseal the trait. That would allow soundly (but unsafely) implementing this for e.g. a `#[repr(C)] struct` that should be passable by varargs.
Relates to https://github.com/rust-lang/rust/issues/44930
Tweak a confusing comment in `create_match_candidates`
This comment was accurate at the time it was written, but various later changes reshuffled things in ways that caused the existing comment to become confusing.
I've therefore tried to clarify that *these* candidates are 1:1 with match arms, while also warning that that isn't the case in general.
Specify target specific linker for `riscv64gc-gnu` job
In https://github.com/rust-lang/rust/pull/125669 I updated the `riscv64gc-gnu` job to be more in line with other jobs, like the `armhf-gnu` one.
I missed something important, though! Since the `riscv64gc-unknown-linux-gnu` builds go through a cross compiler, invoking `cc` is not correct! That would invoke the `x86_64-unknown-linux-gnu` linker, instead of the `riscv64gc-unknown-linux-gnu` linker.
While developing #125669 I assumed this line would have been sufficient, however it was not:
553a69030e/src/ci/docker/host-x86_64/disabled/riscv64gc-gnu/Dockerfile (L27-L28)
Unfortunately, without the linker set, `cc` is invoked, and the following linker error occurs:
<details>
<summary>Long output</summary>
```
2024-06-21T14:37:54.4786899Z === HAYSTACK ===
2024-06-21T14:37:54.4787240Z error: linking with `cc` failed: exit status: 1
2024-06-21T14:37:54.4787589Z |
2024-06-21T14:37:54.4806781Z = note: LC_ALL="C" PATH="/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/lib/rustlib/x86_64-unknown-linux-gnu/bin:/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/lib/rustlib/x86_64-unknown-linux-gnu/bin:/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/lib/rustlib/x86_64-unknown-linux-gnu/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin" VSLANG="1033" "cc" "/tmp/rustc7Ju6va/symbols.o" "inaccessible/tmp/program.program.45572bc5f2b14090-cgu.0.rcgu.o" "inaccessible/tmp/program.dv9uftjrq86w5xa7l2eo7g9l7.rcgu.o" "-Wl,--as-needed" "-L" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/run-make/inaccessible-temp-dir/inaccessible-temp-dir/rmake_out" "-L" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/lib/rustlib/riscv64gc-unknown-linux-gnu/lib" "-Wl,-Bstatic" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/lib/rustlib/riscv64gc-unknown-linux-gnu/lib/libstd-bb9ed017b7d70437.rlib" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/lib/rustlib/riscv64gc-unknown-linux-gnu/lib/libpanic_unwind-5b34ef68c22a7b9b.rlib" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/lib/rustlib/riscv64gc-unknown-linux-gnu/lib/libobject-4b9224407e296f51.rlib" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/lib/rustlib/riscv64gc-unknown-linux-gnu/lib/libmemchr-1eaaa8d74bbe0b36.rlib" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/lib/rustlib/riscv64gc-unknown-linux-gnu/lib/libaddr2line-b34292f7086867e9.rlib" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/lib/rustlib/riscv64gc-unknown-linux-gnu/lib/libgimli-1927540c5dff6690.rlib" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/lib/rustlib/riscv64gc-unknown-linux-gnu/lib/librustc_demangle-ab493befe3742702.rlib" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/lib/rustlib/riscv64gc-unknown-linux-gnu/lib/libstd_detect-41195694489636c4.rlib" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/lib/rustlib/riscv64gc-unknown-linux-gnu/lib/libhashbrown-6905da49c8a1542a.rlib" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/lib/rustlib/riscv64gc-unknown-linux-gnu/lib/librustc_std_workspace_alloc-bbc6290f03f92349.rlib" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/lib/rustlib/riscv64gc-unknown-linux-gnu/lib/libminiz_oxide-7a4683d4a82cf47c.rlib" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/lib/rustlib/riscv64gc-unknown-linux-gnu/lib/libadler-071583516cdbce90.rlib" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/lib/rustlib/riscv64gc-unknown-linux-gnu/lib/libunwind-d84b176d2f4c1334.rlib" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/lib/rustlib/riscv64gc-unknown-linux-gnu/lib/libcfg_if-92b7de0160f87442.rlib" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/lib/rustlib/riscv64gc-unknown-linux-gnu/lib/liblibc-cff1533ea7c26263.rlib" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/lib/rustlib/riscv64gc-unknown-linux-gnu/lib/liballoc-49e374c13f9e6132.rlib" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/lib/rustlib/riscv64gc-unknown-linux-gnu/lib/librustc_std_workspace_core-9389dcc15b2f7f7b.rlib" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/lib/rustlib/riscv64gc-unknown-linux-gnu/lib/libcore-46f0fa14905fdc5c.rlib" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/lib/rustlib/riscv64gc-unknown-linux-gnu/lib/libcompiler_builtins-20e1af401f90cd1c.rlib" "-Wl,-Bdynamic" "-lgcc_s" "-lutil" "-lrt" "-lpthread" "-lm" "-ldl" "-lc" "-Wl,--eh-frame-hdr" "-Wl,-z,noexecstack" "-L" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/lib/rustlib/riscv64gc-unknown-linux-gnu/lib" "-o" "program" "-Wl,--gc-sections" "-pie" "-Wl,-z,relro,-z,now" "-nodefaultlibs"
2024-06-21T14:37:54.4823900Z = note: /usr/bin/ld: inaccessible/tmp/program.program.45572bc5f2b14090-cgu.0.rcgu.o: Relocations in generic ELF (EM: 243)
2024-06-21T14:37:54.4825032Z /usr/bin/ld: inaccessible/tmp/program.program.45572bc5f2b14090-cgu.0.rcgu.o: Relocations in generic ELF (EM: 243)
2024-06-21T14:37:54.4826130Z /usr/bin/ld: inaccessible/tmp/program.program.45572bc5f2b14090-cgu.0.rcgu.o: Relocations in generic ELF (EM: 243)
2024-06-21T14:37:54.4827200Z /usr/bin/ld: inaccessible/tmp/program.program.45572bc5f2b14090-cgu.0.rcgu.o: Relocations in generic ELF (EM: 243)
2024-06-21T14:37:54.4828279Z /usr/bin/ld: inaccessible/tmp/program.program.45572bc5f2b14090-cgu.0.rcgu.o: Relocations in generic ELF (EM: 243)
2024-06-21T14:37:54.4829365Z /usr/bin/ld: inaccessible/tmp/program.program.45572bc5f2b14090-cgu.0.rcgu.o: Relocations in generic ELF (EM: 243)
2024-06-21T14:37:54.4830474Z /usr/bin/ld: inaccessible/tmp/program.program.45572bc5f2b14090-cgu.0.rcgu.o: Relocations in generic ELF (EM: 243)
2024-06-21T14:37:54.4831554Z /usr/bin/ld: inaccessible/tmp/program.program.45572bc5f2b14090-cgu.0.rcgu.o: Relocations in generic ELF (EM: 243)
2024-06-21T14:37:54.4833002Z /usr/bin/ld: inaccessible/tmp/program.program.45572bc5f2b14090-cgu.0.rcgu.o: Relocations in generic ELF (EM: 243)
2024-06-21T14:37:54.4834116Z /usr/bin/ld: inaccessible/tmp/program.program.45572bc5f2b14090-cgu.0.rcgu.o: Relocations in generic ELF (EM: 243)
2024-06-21T14:37:54.4835237Z /usr/bin/ld: inaccessible/tmp/program.program.45572bc5f2b14090-cgu.0.rcgu.o: error adding symbols: file in wrong format
2024-06-21T14:37:54.4835971Z collect2: error: ld returned 1 exit status
2024-06-21T14:37:54.4836449Z
2024-06-21T14:37:54.4836584Z
2024-06-21T14:37:54.4836744Z error: aborting due to 1 previous error
2024-06-21T14:37:54.4836983Z
2024-06-21T14:37:54.4836990Z
2024-06-21T14:37:54.4837083Z === NEEDLE ===
2024-06-21T14:37:54.4837518Z failed to find or create the directory specified by `--temps-dir`
2024-06-21T14:37:54.4838250Z thread 'main' panicked at /checkout/tests/run-make/inaccessible-temp-dir/rmake.rs:35:14:
2024-06-21T14:37:54.4838801Z needle was not found in haystack
2024-06-21T14:37:54.4839270Z note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
2024-06-21T14:37:54.4840125Z thread 'main' panicked at /checkout/tests/run-make/inaccessible-temp-dir/rmake.rs:27:5:
2024-06-21T14:37:54.4840759Z called `Result::unwrap()` on an `Err` value: Any { .. }
2024-06-21T14:37:54.4841194Z ------------------------------------------
```
</details>
By setting `--set target.riscv64gc-unknown-linux-gnu.linker=riscv64-linux-gnu-gcc` the correct linker is invoked.
## Testing
> [!NOTE]
> `riscv64gc-unknown-linux-gnu` is a [**Tier 2 with Host Tools** platform](https://doc.rust-lang.org/beta/rustc/platform-support.html), all tests may not necessarily pass! This change should only make fix existing broken tests (like `inaccessible-temp-dir`) while introducing no new breakage.
You can test out the job locally:
```sh
mv src/ci/docker/host-x86_64/disabled/riscv64gc-gnu src/ci/docker/host-x86_64/riscv64gc-gnu
DEPLOY=1 ./src/ci/docker/run.sh riscv64gc-gnu
```
Detect unused structs which derived Default
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Fixes#98871
ast: Standardize visiting order for attributes and node IDs
This should only affect `macro_rules` scopes and order of diagnostics.
Also add a deprecation lint for `macro_rules` called outside of their scope, like in https://github.com/rust-lang/rust/issues/124535.
Various refactorings to rustc_interface
This should make it easier to move the driver interface away from queries in the future. Many custom drivers call queries like `queries.global_ctxt()` before they are supposed to be called, breaking some things like certain `--print` and `-Zunpretty` options, `-Zparse-only` and emitting the dep info at the wrong point in time. They are also not actually necessary at all. Passing around the query output manually would avoid recomputation too and would be just as easy. Removing driver queries would also reduce the amount of global mutable state of the compiler. I'm not removing driver queries in this PR to avoid breaking the aforementioned custom drivers.
It was somewhat confusing that the old constructor would create a `FlatPat` in
a (possibly) non-simplified state, and then simplify its contents in-place.
So instead we now create its fields as local variables, perform simplification,
and then create the struct afterwards.
This doesn't affect correctness, but is less confusing.
transmute size check: properly account for alignment
Fixes another place where ZST alignment was ignored when checking whether something is a newtype. I wonder how many more of these there are...
Fixes https://github.com/rust-lang/rust/issues/101084
Allow constraining opaque types during various unsizing casts
allows unsizing of tuples, arrays and Adts to constraint opaque types in their generic parameters to concrete types on either side of the unsizing cast.
Also allows constraining opaque types during trait object casts that only differ in auto traits or lifetimes.
cc #116652
`T: VaArgSafe` is relied on for soundness. Safe impls promise nothing.
Therefore this must be an unsafe trait. Slightly pedantic, as
only core can impl this, but we could choose to unseal the trait.
That would allow soundly (but unsafely) implementing this for e.g.
a `#[repr(C)] struct` that should be passable by varargs.
Add `SliceLike` to `rustc_type_ir`, use it in the generic solver code (+ some other changes)
First, we split out `TraitRef::new_from_args` which takes *just* `ty::GenericArgsRef` from `TraitRef::new` which takes `impl IntoIterator<Item: Into<GenericArg>>`. I will explain in a minute why.
Second, we introduce `SliceLike`, which allows us to be generic over `List<T>` and `[T]`. This trait has an `as_slice()` and `into_iter()` method, and some other convenience functions. However, importantly, since types like `I::GenericArgs` now implement `SliceLike` rather than `IntoIter<Item = I::GenericArg>`, we can't use `TraitRef::new` on this directly. That's where `new_from_args` comes in.
Finally, we adjust all the code to use these slice operators. Some things get simpler, some things get a bit more annoying since we need to use `as_slice()` in a few places. 🤷
r? lcnr
Rollup of 11 pull requests
Successful merges:
- #124460 (Show notice about "never used" of Debug for enum)
- #124712 (Deprecate no-op codegen option `-Cinline-threshold=...`)
- #125082 (Remove `MaybeUninit::uninit_array()` and replace it with inline const blocks.)
- #125575 (SmartPointer derive-macro)
- #126413 (compiletest: make the crash test error message abit more informative)
- #126673 (Ensure we don't accidentally succeed when we want to report an error)
- #126682 (coverage: Overhaul validation of the `#[coverage(..)]` attribute)
- #126899 (Suggest inline const blocks for array initialization)
- #126904 (Small fixme in core now that NonZero is generic)
- #126909 (add `@kobzol` to bootstrap team for triagebot)
- #126911 (Split the lifetimes of `MirBorrowckCtxt`)
r? `@ghost`
`@rustbot` modify labels: rollup
Split the lifetimes of `MirBorrowckCtxt`
These lifetimes are sometimes too general and will link things together that are independent. These are a blocker for actually finishing tracking more state (e.g. error tainting) in the diagnostic context handle, and I'd rather land it in its own PR instead of together with functional changes.
Also changes a bunch of named lifetimes to `'_` where they were irrelevant
follow-up to https://github.com/rust-lang/rust/pull/126623
coverage: Overhaul validation of the `#[coverage(..)]` attribute
This PR makes sweeping changes to how the (currently-unstable) coverage attribute is validated:
- Multiple coverage attributes on the same item/expression are now treated as an error.
- The attribute must always be `#[coverage(off)]` or `#[coverage(on)]`, and the error messages for this are more consistent.
- A trailing comma is still allowed after off/on, since that's part of the normal attribute syntax.
- Some places that silently ignored a coverage attribute now produce an error instead.
- These cases were all clearly bugs.
- Some places that ignored a coverage attribute (with a warning) now produce an error instead.
- These were originally added as lints, but I don't think it makes much sense to knowingly allow new attributes to be used in meaningless places.
- Some of these errors might soon disappear, if it's easy to extend recursive coverage attributes to things like modules and impl blocks.
---
One of the goals of this PR is to lay a more solid foundation for making the coverage attribute recursive, so that it applies to all nested functions/closures instead of just the one it is directly attached to.
Fixes#126658.
This PR incorporates #126659, which adds more tests for validation of the coverage attribute.
`@rustbot` label +A-code-coverage
Ensure we don't accidentally succeed when we want to report an error
This also changes the `DefiningOpaqueTypes::No` to `Yes` without adding tests, as it is solely run on the error path to improve diagnostics. I was unable to provide a test that changes diagnostics, as all the tests I came up with ended up successfully constraining the opaque type and thus succeeding the coercion.
r? ```@compiler-errors```
cc https://github.com/rust-lang/rust/issues/116652
SmartPointer derive-macro
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Possibly replacing #123472 for continued upkeep of the proposal rust-lang/rfcs#3621 and implementation of the tracking issue #123430.
cc `@Darksonn` `@wedsonaf`
Remove `MaybeUninit::uninit_array()` and replace it with inline const blocks.
\[This PR originally contained the changes in #125995 too. See edit history for the original PR description.]
The documentation of `MaybeUninit::uninit_array()` says:
> Note: in a future Rust version this method may become unnecessary when Rust allows [inline const expressions](https://github.com/rust-lang/rust/issues/76001). The example below could then use `let mut buf = [const { MaybeUninit::<u8>::uninit() }; 32];`.
The PR adding it also said: <https://github.com/rust-lang/rust/pull/65580#issuecomment-544200681>
> if it’s stabilized soon enough maybe it’s not worth having a standard library method that will be replaceable with `let buffer = [MaybeUninit::<T>::uninit(); $N];`
That time has come to pass — inline const expressions are stable — so `MaybeUninit::uninit_array()` is now unnecessary. The only remaining question is whether it is an important enough *convenience* to keep it around.
I believe it is net good to remove this function, on the principle that it is better to compose two orthogonal features (`MaybeUninit` and array construction) than to have a specific function for the specific combination, now that that is possible.
Deprecate no-op codegen option `-Cinline-threshold=...`
This deprecates `-Cinline-threshold` since using it has no effect. This has been the case since the new LLVM pass manager started being used, more than 2 years ago.
Recommend using `-Cllvm-args=--inline-threshold=...` instead.
Closes#89742 which is E-help-wanted.
Show notice about "never used" of Debug for enum
Close#123068
If an ADT implements `Debug` trait and it is not used, the compiler says a note that indicates intentionally ignored during dead code analysis as [this note](2207179a59/tests/ui/lint/dead-code/unused-variant.stderr (L9)).
However this node is not shown for variants that have fields in enum. This PR fixes to show the note.
Save 2 pointers in `TerminatorKind` (96 → 80 bytes)
These things don't need to be `Vec`s; boxed slices are enough.
The frequent one here is call arguments, but MIR building knows the number of arguments from the THIR, so the collect is always getting the allocation right in the first place, and thus this shouldn't ever add the shrink-in-place overhead.
This is possible now that inline const blocks are stable; the idea was
even mentioned as an alternative when `uninit_array()` was added:
<https://github.com/rust-lang/rust/pull/65580#issuecomment-544200681>
> if it’s stabilized soon enough maybe it’s not worth having a
> standard library method that will be replaceable with
> `let buffer = [MaybeUninit::<T>::uninit(); $N];`
Const array repetition and inline const blocks are now stable (in the
next release), so that circumstance has come to pass, and we no longer
have reason to want `uninit_array()` other than convenience. Therefore,
let’s evaluate the inconvenience by not using `uninit_array()` in
the standard library, before potentially deleting it entirely.
std: refactor the TLS implementation
As discovered by Mara in #110897, our TLS implementation is a total mess. In the past months, I have simplified the actual macros and their expansions, but the majority of the complexity comes from the platform-specific support code needed to create keys and register destructors. In keeping with #117276, I have therefore moved all of the `thread_local_key`/`thread_local_dtor` modules to the `thread_local` module in `sys` and merged them into a new structure, so that future porters of `std` can simply mix-and-match the existing code instead of having to copy the same (bad) implementation everywhere. The new structure should become obvious when looking at `sys/thread_local/mod.rs`.
Unfortunately, the documentation changes associated with the refactoring have made this PR rather large. That said, this contains no functional changes except for two small ones:
* the key-based destructor fallback now, by virtue of sharing the implementation used by macOS and others, stores its list in a `#[thread_local]` static instead of in the key, eliminating one indirection layer and drastically simplifying its code.
* I've switched over ZKVM (tier 3) to use the same implementation as WebAssembly, as the implementation was just a way worse version of that
Please let me know if I can make this easier to review! I know these large PRs aren't optimal, but I couldn't think of any good intermediate steps.
`@rustbot` label +A-thread-locals
