Auto merge of #96042 - m-ou-se:one-reentrant-mutex, r=Amanieu
Use a single ReentrantMutex implementation on all platforms.
This replaces all platform specific ReentrantMutex implementations by the one I added in #95727 for Linux, since that one does not depend on any platform specific details.
Auto merge of #96080 - nikic:ranlib, r=Mark-Simulacrum
Respect ranlib specified for target during LLVM build
The ranlib specified for the target was never actually transferred
into the builder configuration. In the dist-x86_64-linux build we
ended up using ranlib instead of llvm-ranlib.
Found this investigating a build failure in #94214.
Auto merge of #96000 - jyn514:faster-doctests, r=Mark-Simulacrum
Make `x test --stage 2 compiler/rustc_XXX` faster to run
Previously, bootstrap unconditionally rebuilt the stage 2 compiler,
even if it had previously built stage 1. This changes it to reuse stage 1 if possible.
In particular, it no longer runs the following step:
```
Building stage1 compiler artifacts (x86_64-unknown-linux-gnu(x86_64-unknown-linux-gnu) -> x86_64-unknown-linux-gnu(x86_64-unknown-linux-gnu))
```
Auto merge of #95695 - the8472:vec-codegen-tests, r=Mark-Simulacrum
Add codegen tests for additional cases where noop iterators get optimized away
Optimizations have improved over time and now LLVM manages to optimize more in-place-collect noop-iterators to O(1) functions. This updates the codegen test to match.
Many but not all cases reported in #79308 work now.
Auto merge of #93530 - anonion0:pthread_sigmask_fix, r=JohnTitor
fix error handling for pthread_sigmask(3)
Errors from `pthread_sigmask(3)` were handled using `cvt()`, which expects a return value of `-1` on error and uses `errno`.
However, `pthread_sigmask(3)` returns `0` on success and an error number otherwise.
Auto merge of #95779 - cjgillot:ast-lifetimes-undeclared, r=petrochenkov
Report undeclared lifetimes during late resolution.
First step in https://github.com/rust-lang/rust/pull/91557
We reuse the rib design of the current resolution framework. Specific `LifetimeRib` and `LifetimeRibKind` types are introduced. The most important variant is `LifetimeRibKind::Generics`, which happens each time we encounter something which may introduce generic lifetime parameters. It can be an item or a `for<...>` binder. The `LifetimeBinderKind` specifies how this rib behaves with respect to in-band lifetimes.
Auto merge of #95655 - kckeiks:create-hir-crate-items-query, r=cjgillot
Refactor HIR item-like traversal (part 1)
Issue #95004
- Create hir_crate_items query which traverses tcx.hir_crate(()).owners to return a hir::ModuleItems
- use tcx.hir_crate_items in tcx.hir().items() to return an iterator of hir::ItemId
- use tcx.hir_crate_items to introduce a tcx.hir().par_items(impl Fn(hir::ItemId)) to traverse all items in parallel;
Signed-off-by: Miguel Guarniz <mi9uel9@gmail.com>
cc `@cjgillot`
Auto merge of #96002 - nnethercote:speed-up-Vec-clear-2, r=m-ou-se
Speed up Vec::clear().
Currently it just calls `truncate(0)`. `truncate()` is (a) not marked as
`#[inline]`, and (b) more general than needed for `clear()`.
This commit changes `clear()` to do the work itself. This modest change
was first proposed in rust-lang#74172, where the reviewer rejected it because
there was insufficient evidence that `Vec::clear()`'s performance
mattered enough to justify the change. Recent changes within rustc have
made `Vec::clear()` hot within `macro_parser.rs`, so the change is now
clearly worthwhile.
Although it doesn't show wins on CI perf runs, this seems to be because they
use PGO. But not all platforms currently use PGO. Also, local builds don't use
PGO, and `truncate` sometimes shows up in an over-represented fashion in local
profiles. So local profiling will be made easier by this change.
Note that this will also benefit `String::clear()`, because it just
calls `Vec::clear()`.
Finally, the commit removes the `vec-clear.rs` codegen test. It was
added in #52908. From before then until now, `Vec::clear()` just called
`Vec::truncate()` with a zero length. The body of Vec::truncate() has
changed a lot since then. Now that `Vec::clear()` is doing actual work
itself, and not just calling `Vec::truncate()`, it's not surprising that
its generated code includes a load and an icmp. I think it's reasonable
to remove this test.
Auto merge of #96134 - Dylan-DPC:rollup-ejug3yq, r=Dylan-DPC
Rollup of 6 pull requests
Successful merges:
- #95346 (Stablize `const_extern_fn` for "Rust" and "C")
- #95933 (htmldocck: Compare HTML tree instead of plain text html)
- #96105 (Make the debug output for `TargetSelection` less verbose)
- #96112 (Strict provenance lint diagnostics improvements)
- #96119 (update Miri)
- #96124 (to_digit tweak)
Rollup merge of #96112 - niluxv:strict-provenance-lint-improvements, r=nagisa
Strict provenance lint diagnostics improvements
Use `multipart_suggestion` instead of `span_suggestion` and getting a snippet for the expression. Also don't suggest unnecessary parenthesis in `lossy_provenance_casts`.
cc ``@estebank``
``@rustbot`` label A-diagnostics
Rollup merge of #95933 - Urgau:rustdoc-htmldocck-tree-compare, r=GuillaumeGomez
htmldocck: Compare HTML tree instead of plain text html
This PR improves `htmldocck` by comparing HTML trees instead of plain text html in the case of doing a ```@snapshot``` test.
This fix the [CI issue](https://github.com/rust-lang-ci/rust/runs/5964305020?check_suite_focus=true) encounter in https://github.com/rust-lang/rust/pull/95813 where for some unknown reason one of the attributes is not always at the same place.
The code is largely based on https://github.com/formencode/formencode/blob/3a1ba9de2fdd494dd945510a4568a3afeddb0b2e/formencode/doctest_xml_compare.py#L72-L120 which is behind MIT License. The comparison function is straightforward except for the `text_compare` function which does some weird stuff that we may want to simply reduce to a plain old comparison.
Auto merge of #95899 - petrochenkov:modchild2, r=cjgillot
rustc_metadata: Do not encode unnecessary module children
This should remove the syntax context shift and the special case for `ExternCrate` in decoder in https://github.com/rust-lang/rust/pull/95880.
This PR also shifts some work from decoding to encoding, which is typically useful for performance (but probably not much in this case).
r? `@cjgillot`
Auto merge of #96123 - Dylan-DPC:rollup-qjog6n1, r=Dylan-DPC
Rollup of 7 pull requests
Successful merges:
- #94985 (Parse inner attributes on inline const block)
- #95006 (Reject `#[thread_local]` attribute on non-static items)
- #95426 (Include Refs in Valtree Creation)
- #95908 (Inline `shallow_resolve_ty` into `ShallowResolver`)
- #96058 (separate flock implementations into separate modules)
- #96088 (Update mdbook)
- #96118 (rustdoc: Rename `def_id` into `item_id` when the type is `ItemId` for readability)
Rollup merge of #96118 - GuillaumeGomez:cleanup-def-id-item-id, r=notriddle
rustdoc: Rename `def_id` into `item_id` when the type is `ItemId` for readability
As `@notriddle` mentioned in https://github.com/rust-lang/rust/pull/96091, the field name is inaccurate. This PR fixes it by renaming it accordingly to its real type.
Rollup merge of #96088 - ehuss:update-mdbook, r=Mark-Simulacrum
Update mdbook
This just brings in a few small fixes, particularly a rendering fix for chapter names with markdown in them (like the https://doc.rust-lang.org/nightly/rustc/platform-support/kmc-solid.html page). There's also a minor fix for the search index for duplicate headings.
Rollup merge of #95426 - b-naber:valtrees-slice, r=RalfJung,oli-obk
Include Refs in Valtree Creation
This adds references to `const_to_valtree`, which isn't used in the compiler yet, but after the previous changes we made to the thir and mir representations and this change we should be able to finally introduce them in the next PR.
I wasn't able to properly test this code, except indirectly by including a call of `const_to_valtree` in the code that currently creates constants (`turn_into_const_value`).
Rollup merge of #94985 - dtolnay:constattr, r=pnkfelix
Parse inner attributes on inline const block
According to https://github.com/rust-lang/rust/pull/84414#issuecomment-826150936, inner attributes are intended to be supported *"in all containers for statements (or some subset of statements)"*.
This PR adds inner attribute parsing and pretty-printing for inline const blocks (https://github.com/rust-lang/rust/issues/76001), which contain statements just like an unsafe block or a loop body.
Auto merge of #95993 - jyn514:fix-stage0-doctests, r=Mark-Simulacrum
Fix `x test --doc --stage 0 library/std`
I managed to break this in https://github.com/rust-lang/rust/pull/95449.
I am not quite sure why this is the correct fix, but it doesn't break `doc --stage 0`
and is strictly closer to the previous behavior.
Previously, rustdoc would error with strange issues because of the mismatched sysroot:
```
error[E0460]: found possibly newer version of crate `std` which `rustc_span` depends on
--> /home/jnelson/rust-lang/rust/compiler/rustc_lint_defs/src/lib.rs:14:5
|
14 | use rustc_span::{sym, symbol::Ident, Span, Symbol};
| ^^^^^^^^^^
|
= note: perhaps that crate needs to be recompiled?
= note: the following crate versions were found:
crate `std`: /home/jnelson/rust-lang/rust/build/x86_64-unknown-linux-gnu/stage0/lib/rustlib/x86_64-unknown-linux-gnu/lib/libstd-ff9290e971253a38.rlib
crate `std`: /home/jnelson/rust-lang/rust/build/x86_64-unknown-linux-gnu/stage0/lib/rustlib/x86_64-unknown-linux-gnu/lib/libstd-ff9290e971253a38.so
crate `rustc_span`: /home/jnelson/rust-lang/rust/build/x86_64-unknown-linux-gnu/stage0-rustc/x86_64-unknown-linux-gnu/release/deps/librustc_span-ed11dce30c1766f9.rlib
```
Auto merge of #96117 - Dylan-DPC:rollup-5traczf, r=Dylan-DPC
Rollup of 7 pull requests
Successful merges:
- #95887 (resolve: Create dummy bindings for all unresolved imports)
- #96023 (couple of clippy::perf fixes)
- #96035 (Update GitHub Actions actions/checkout Version v2 -> v3)
- #96038 (docs: add link from zip to unzip)
- #96047 (:arrow_up: rust-analyzer)
- #96059 (clarify doc(cfg) wording)
- #96081 (Make some `usize`-typed masks definitions agnostic to the size of `usize`)
Rollup merge of #96081 - eduardosm:masks_usize_size_agnostic, r=yaahc
Make some `usize`-typed masks definitions agnostic to the size of `usize`
Some masks where defined as
```rust
const NONASCII_MASK: usize = 0x80808080_80808080u64 as usize;
```
where it was assumed that `usize` is never wider than 64, which is currently true.
To make those constants valid in a hypothetical 128-bit target, these constants have been redefined in an `usize`-width-agnostic way
```rust
const NONASCII_MASK: usize = usize::from_ne_bytes([0x80; size_of::<usize>()]);
```
There are already some cases where Rust anticipates the possibility of supporting 128-bit targets, such as not implementing `From<usize>` for `u64`.
Rollup merge of #96059 - euclio:doc-cfg, r=manishearth,guillaumegomez
clarify doc(cfg) wording
The current "This is supported" wording implies that it's possible to
still use the item on other configurations, but in an unsupported way.
Changing this to "Available" removes this ambiguity.
Rollup merge of #96038 - beyarkay:patch-1, r=m-ou-se
docs: add link from zip to unzip
The docs for `Iterator::unzip` explain that it is kind of an inverse operation to `Iterator::zip` and guide the reader to the `zip` docs, but the `zip` docs don't let the user know that they can undo the `zip` operation with `unzip`. This change modifies the docs to help the user find `unzip`.
Rollup merge of #96035 - Gumichocopengin8:feature/update-github-action-version, r=pietroalbini
Update GitHub Actions actions/checkout Version v2 -> v3
Update `actions/checkout@v2` to `actions/checkout@v3` because of Node12 will be out of life after Aril 30, 2022 [[Reference](https://nodejs.org/en/about/releases/)].
`actions/xxxx@v3` use Node16 whose support lasts until April 30, 2024.
Rollup merge of #95887 - petrochenkov:doclink5, r=cjgillot
resolve: Create dummy bindings for all unresolved imports
Apparently such bindings weren't previously created for all unresolved imports, causing issues like https://github.com/rust-lang/rust/issues/95879.
In this PR I'm trying to create such dummy bindings in a more centralized way by calling `import_dummy_binding` once for all imports in `finalize_imports`.
Auto merge of #95689 - lqd:self-profiler, r=wesleywiser
Allow self-profiler to only record potentially costly arguments when argument recording is turned on
As discussed [on zulip](https://rust-lang.zulipchat.com/#narrow/stream/247081-t-compiler.2Fperformance/topic/Identifying.20proc-macro.20slowdowns/near/277304909) with `@wesleywiser,` I'd like to record proc-macro expansions in the self-profiler, with some detailed data (per-expansion spans for example, to follow #95473).
At the same time, I'd also like to avoid doing expensive things when tracking a generic activity's arguments, if they were not specifically opted into the event filter mask, to allow the self-profiler to be used in hotter contexts.
This PR tries to offer:
- a way to ensure a closure to record arguments will only be called in that situation, so that potentially costly arguments can still be recorded when needed. With the additional requirement that, if possible, it would offer a way to record non-owned data without adding many `generic_activity_with_arg_{...}`-style methods. This lead to the `generic_activity_with_arg_recorder` single entry-point, and the closure parameter would offer the new methods, able to be executed in a context where costly argument could be created without disturbing the profiled piece of code.
- some facilities/patterns allowing to record more rustc specific data in this situation, without making `rustc_data_structures` where the self-profiler is defined, depend on other rustc crates (causing circular dependencies): in particular, spans. They are quite tricky to turn into strings (if the default `Debug` impl output does not match the context one needs them for), and since I'd also like to avoid the allocation there when arg recording is turned off today, that has turned into another flexibility requirement for the API in this PR (separating the span-specific recording into an extension trait). **edit**: I've removed this from the PR so that it's easier to review, and opened https://github.com/rust-lang/rust/pull/95739.
- allow for extensibility in the future: other ways to record arguments, or additional data attached to them could be added in the future (e.g. recording the argument's name as well as its data).
Some areas where I'd love feedback:
- the API and names: the `EventArgRecorder` and its method for example. As well as the verbosity that comes from the increased flexibility.
- if I should convert the existing `generic_activity_with_arg{s}` to just forward to `generic_activity_with_arg_recorder` + `recorder.record_arg` (or remove them altogether ? Probably not): I've used the new API in the simple case I could find of allocating for an arg that may not be recorded, and the rest don't seem costly.
- [x] whether this API should panic if no arguments were recorded by the user-provided closure (like this PR currently does: it seems like an error to use an API dedicated to record arguments but not call the methods to then do so) or if this should just record a generic activity without arguments ?
- whether the `record_arg` function should be `#[inline(always)]`, like the `generic_activity_*` functions ?
As mentioned, r? `@wesleywiser` following our recent discussion.
Auto merge of #96108 - Dylan-DPC:rollup-t5f2fc9, r=Dylan-DPC
Rollup of 9 pull requests
Successful merges:
- #93969 (Only add codegen backend to dep info if -Zbinary-dep-depinfo is used)
- #94605 (Add missing links in platform support docs)
- #95372 (make unaligned_references lint deny-by-default)
- #95859 (Improve diagnostics for unterminated nested block comment)
- #95961 (implement SIMD gather/scatter via vector getelementptr)
- #96004 (Consider lifetimes when comparing types for equality in MIR validator)
- #96050 (Remove some now-dead code that was only relevant before deaggregation.)
- #96070 ([test] Add test cases for untested functions for BTreeMap)
- #96099 (MaybeUninit array cleanup)
Auto merge of #92364 - jackh726:Quantumplation/65853/param-heuristics, r=estebank
Better method call error messages
Rebase/continuation of #71827
~Based on #92360~
~Based on #93118~
There's a decent description in #71827 that I won't copy here (for now at least)
In addition to rebasing, I've tried to restore most of the original suggestions for invalid arguments. Unfortunately, this does make some of the errors a bit verbose. To fix this will require a bit of refactoring to some of the generalized error suggestion functions, and I just don't have the time to go into it right now.
I think this is in a state that the error messages are overall better than before without a reduction in the suggestions given.
~I've tried to split out some of the easier and self-contained changes into separate commits (mostly in #92360, but also one here). There might be more than can be done here, but again just lacking time.~
Jack Huey [Sat, 22 Jan 2022 04:50:54 +0000 (23:50 -0500)]
Implementation for 65853
This attempts to bring better error messages to invalid method calls, by applying some heuristics to identify common mistakes.
The algorithm is inspired by Levenshtein distance and longest common sub-sequence. In essence, we treat the types of the function, and the types of the arguments you provided as two "words" and compute the edits to get from one to the other.
We then modify that algorithm to detect 4 cases:
- A function input is missing
- An extra argument was provided
- The type of an argument is straight up invalid
- Two arguments have been swapped
- A subset of the arguments have been shuffled
(We detect the last two as separate cases so that we can detect two swaps, instead of 4 parameters permuted.)
It helps to understand this argument by paying special attention to terminology: "inputs" refers to the inputs being *expected* by the function, and "arguments" refers to what has been provided at the call site.
The basic sketch of the algorithm is as follows:
- Construct a boolean grid, with a row for each argument, and a column for each input. The cell [i, j] is true if the i'th argument could satisfy the j'th input.
- If we find an argument that could satisfy no inputs, provided for an input that can't be satisfied by any other argument, we consider this an "invalid type".
- Extra arguments are those that can't satisfy any input, provided for an input that *could* be satisfied by another argument.
- Missing inputs are inputs that can't be satisfied by any argument, where the provided argument could satisfy another input
- Swapped / Permuted arguments are identified with a cycle detection algorithm.
As each issue is found, we remove the relevant inputs / arguments and check for more issues. If we find no issues, we match up any "valid" arguments, and start again.
Note that there's a lot of extra complexity:
- We try to stay efficient on the happy path, only computing the diagonal until we find a problem, and then filling in the rest of the matrix.
- Closure arguments are wrapped in a tuple and need to be unwrapped
- We need to resolve closure types after the rest, to allow the most specific type constraints
- We need to handle imported C functions that might be variadic in their inputs.
I tried to document a lot of this in comments in the code and keep the naming clear.
Rollup merge of #96099 - clarfonthey:maybeuninit_array_cleanup, r=dtolnay
MaybeUninit array cleanup
* Links `MaybeUninit::uninit_array` to meta-tracking issue
* Links `MaybeUninit::array_assume_init` to meta-tracking issue
* Unstably constifies `MaybeUninit::array_assume_init`
Another thing worth mentioning: this splits the const feature flag for `maybe_uninit_uninit_array` into `const_maybe_uninit_uninit_array` to avoid weird cases where only one gets stabilised.
Note that it may be desired to keep the `array_assume_init` method linked to its dedicated issue, but at least for now, I decided to link to the meta-tracking issue so that all of the methods lead users to the same place. But I can revert that bit if desired.
However, I don't *really* know what I am doing here... Cc ``@workingjubilee`` ``@calebzulawski``
I didn't do anything for cranelift -- ``@bjorn3`` not sure if it's okay for that backend to temporarily break. I'm happy to cherry-pick a patch that adds cranelift support. :)
Rollup merge of #95372 - RalfJung:unaligned_references, r=oli-obk
make unaligned_references lint deny-by-default
This lint has been warn-by-default for a year now (since https://github.com/rust-lang/rust/pull/82525), so I think it is time to crank it up a bit. Code that triggers the lint causes UB (without `unsafe`) when executed, so we really don't want people to write code like this.
Rollup merge of #94605 - Michcioperz:patch-1, r=pnkfelix
Add missing links in platform support docs
I was looking at m68k support and saw that https://doc.rust-lang.org/rustc/platform-support.html and the sidebar there were missing some links to target documentation
Rollup merge of #93969 - bjorn3:codegen_backend_dep_info, r=pnkfelix
Only add codegen backend to dep info if -Zbinary-dep-depinfo is used
I am currently migrating the cg_clif build system from using a binary linked to the codegen backend as rustc replacement to passing `-Zcodegen-backend` instead. Without this PR this would force cargo to rebuild the sysroot on any change to the codegen backend even if I explicitly specify that I want it to be preserved, which would make development of cg_clif a lot slower. If you still want to have changes to the codegen backend invalidate the cargo build cache you can explicitly specify `-Zbinary-dep-depinfo`.
cc ``@eddyb`` as the codegen backend was initially added to the depinfo for rust-gpu.
Auto merge of #94468 - Amanieu:global_asm_sym, r=nagisa
Implement sym operands for global_asm!
Tracking issue: #93333
This PR is pretty much a complete rewrite of `sym` operand support for inline assembly so that the same implementation can be shared by `asm!` and `global_asm!`. The main changes are:
- At the AST level, `sym` is represented as a special `InlineAsmSym` AST node containing a path instead of an `Expr`.
- At the HIR level, `sym` is split into `SymStatic` and `SymFn` depending on whether the path resolves to a static during AST lowering (defaults to `SynFn` if `get_early_res` fails).
- `SymFn` is just an `AnonConst`. It runs through typeck and we just collect the resulting type at the end. An error is emitted if the type is not a `FnDef`.
- `SymStatic` directly holds a path and the `DefId` of the `static` that it is pointing to.
- The representation at the MIR level is mostly unchanged. There is a minor change to THIR where `SymFn` is a constant instead of an expression.
- At the codegen level we need to apply the target's symbol mangling to the result of `tcx.symbol_name()` depending on the target. This is done by calling the LLVM name mangler, which handles all of the details.
- On Mach-O, all symbols have a leading underscore.
- On x86 Windows, different mangling is used for cdecl, stdcall, fastcall and vectorcall.
- No mangling is needed on other platforms.
Inspired by this internals thread: https://internals.rust-lang.org/t/rc-optimization-on-64-bit-targets/16362
[The generated assembly is a bit smaller](https://rust.godbolt.org/z/TeTnf6144) and is a more efficient usage of the CPU's instruction cache. `unlikely` doesn't impact any of the small artificial tests I've done, but I've included it in case it might help more complex scenarios when this is inlined.
Auto merge of #96087 - Dylan-DPC:rollup-k6yzk55, r=Dylan-DPC
Rollup of 11 pull requests
Successful merges:
- #94457 (Stabilize `derive_default_enum`)
- #94461 (Create (unstable) 2024 edition)
- #94849 (Check var scope if it exist)
- #95194 (remove find_use_placement)
- #95749 (only downgrade selection Error -> Ambiguous if type error is in predicate)
- #96026 (couple of clippy::complexity fixes)
- #96027 (remove function parameters only used in recursion)
- #96034 ([test] Add test cases of untested functions for BTreeSet )
- #96040 (Use u32 instead of i32 for futexes.)
- #96062 (docs: Update tests chapter for Termination stabilization)
- #96065 (Refactor: Use `format-args-capture` and remove unnecessary nested blocks in rustc_typeck)
Rollup merge of #96040 - m-ou-se:futex-u32, r=Amanieu
Use u32 instead of i32 for futexes.
This changes futexes from i32 to u32. The [Linux man page](https://man7.org/linux/man-pages/man2/futex.2.html) uses `uint32_t` for them, so I'm not sure why I used i32 for them. Maybe because I first used them for thread parkers, where I used -1, 0, and 1 as the states.
(Wasm's `memory.atomic.wait32` does use `i32`, because wasm doesn't support `u32`.)
It doesn't matter much, but using the unsigned type probably results in fewer surprises when shifting bits around or using comparison operators.
Rollup merge of #96034 - Gumichocopengin8:test/btree-set, r=Dylan-DPC
[test] Add test cases of untested functions for BTreeSet
- add [`is_superset()`](https://doc.rust-lang.org/std/collections/struct.BTreeSet.html#method.is_superset) and [`remove()`](https://doc.rust-lang.org/std/collections/struct.BTreeSet.html#method.remove) test cases for BTreeSet since these functions has no test cases.
Rollup merge of #95194 - kckeiks:update-algo-in-find-use-placement, r=pnkfelix
remove find_use_placement
A more robust solution to finding where to place use suggestions was added in #94584.
The algorithm uses the AST to find the span for the suggestion so we pass this span
down to the HIR during lowering and use it instead of calling `find_use_placement`
Added helper function to check the scope of a variable, if it doesn't have a scope call delay_span_bug, which avoids us trying to get a block/scope that doesn't exist.
Had to increase `ROOT_ENTRY_LIMIT` was getting tidy error
Rollup merge of #94461 - jhpratt:2024-edition, r=pnkfelix
Create (unstable) 2024 edition
[On Zulip](https://rust-lang.zulipchat.com/#narrow/stream/213817-t-lang/topic/Deprecating.20macro.20scoping.20shenanigans/near/272860652), there was a small aside regarding creating the 2024 edition now as opposed to later. There was a reasonable amount of support and no stated opposition.
This change creates the 2024 edition in the compiler and creates a prelude for the 2024 edition. There is no current difference between the 2021 and 2024 editions. Cargo and other tools will need to be updated separately, as it's not in the same repository. This change permits the vast majority of work towards the next edition to proceed _now_ instead of waiting until 2024.
For sanity purposes, I've merged the "hello" UI tests into a single file with multiple revisions. Otherwise we'd end up with a file per edition, despite them being essentially identical.
Rollup merge of #94457 - jhpratt:stabilize-derive_default_enum, r=davidtwco
Stabilize `derive_default_enum`
This stabilizes `#![feature(derive_default_enum)]`, as proposed in [RFC 3107](https://github.com/rust-lang/rfcs/pull/3107) and tracked in #87517. In short, it permits you to `#[derive(Default)]` on `enum`s, indicating what the default should be by placing a `#[default]` attribute on the desired variant (which must be a unit variant in the interest of forward compatibility).
Interesting points:
- Stability:
- To make `CStr(ing)` from libcore/liballoc unusable without enabling features I had to make these structures unstable, and reexport them from libstd using stable type aliases instead of `pub use` reexports. (Because stability of `use` items is not checked.)
- Relying on target ABI in libcore is ok:
- https://github.com/rust-lang/rust/pull/94079#issuecomment-1044263371
- `trait CStrExt` (UPDATE: used only in `cfg(bootstrap)` mode, otherwise lang items are used instead)
- https://github.com/rust-lang/rust/pull/94079#issuecomment-1047863450
- `strlen`
- https://github.com/rust-lang/rust/pull/94079#issuecomment-1047863450
Otherwise it's just a code move + some minor hackery usual for liballoc in `cfg(test)` mode.
Make some `usize`-typed masks definition agnostic to the size of `usize`
Some masks where defined as
```rust
const NONASCII_MASK: usize = 0x80808080_80808080u64 as usize;
```
where it was assumed that `usize` is never wider than 64, which is currently true.
To make those constants valid in a hypothetical 128-bit target, these constants have been redefined in an `usize`-width-agnostic way
```rust
const NONASCII_MASK: usize = usize::from_ne_bytes([0x80; size_of::<usize>()]);
```
There are already some cases where Rust anticipates the possibility of supporting 128-bit targets, such as not implementing `From<usize>` for `u64`.
Respect ranlib specified for target during LLVM build
The ranlib specified for the target was never actually transferred
into the builder configuration. In the dist-x86_64-linux build we
ended up using ranlib instead of llvm-ranlib.