Reduce formatting `width` and `precision` to 16 bits
This is part of https://github.com/rust-lang/rust/issues/99012
This is reduces the `width` and `precision` fields in format strings to 16 bits. They are currently full `usize`s, but it's a bit nonsensical that we need to support the case where someone wants to pad their value to eighteen quintillion spaces and/or have eighteen quintillion digits of precision.
By reducing these fields to 16 bit, we can reduce `FormattingOptions` to 64 bits (see https://github.com/rust-lang/rust/pull/136974) and improve the in memory representation of `format_args!()`. (See additional context below.)
This also fixes a bug where the width or precision is silently truncated when cross-compiling to a target with a smaller `usize`. By reducing the width and precision fields to the minimum guaranteed size of `usize`, 16 bits, this bug is eliminated.
This is a breaking change, but affects almost no existing code.
---
Details of this change:
There are three ways to set a width or precision today:
1. Directly a formatting string, e.g. `println!("{a:1234}")`
2. Indirectly in a formatting string, e.g. `println!("{a:width$}", width=1234)`
3. Through the unstable `FormattingOptions::width` method.
This PR:
- Adds a compiler error for 1. (`println!("{a:9999999}")` no longer compiles and gives a clear error.)
- Adds a runtime check for 2. (`println!("{a:width$}, width=9999999)` will panic.)
- Changes the signatures of the (unstable) `FormattingOptions::[get_]width` methods to use a `u16` instead.
---
Additional context for improving `FormattingOptions` and `fmt::Arguments`:
All the formatting flags and options are currently:
- The `+` flag (1 bit)
- The `-` flag (1 bit)
- The `#` flag (1 bit)
- The `0` flag (1 bit)
- The `x?` flag (1 bit)
- The `X?` flag (1 bit)
- The alignment (2 bits)
- The fill character (21 bits)
- Whether a width is specified (1 bit)
- Whether a precision is specified (1 bit)
- If used, the width (a full usize)
- If used, the precision (a full usize)
Everything except the last two can simply fit in a `u32` (those add up to 31 bits in total).
If we can accept a max width and precision of u16::MAX, we can make a `FormattingOptions` that is exactly 64 bits in size; the same size as a thin reference on most platforms.
If, additionally, we also limit the number of formatting arguments, we can also reduce the size of `fmt::Arguments` (that is, of a `format_args!()` expression).
Revert "Use workspace lints for crates in `compiler/` #138084"
Revert <https://github.com/rust-lang/rust/pull/138084> to buy time to consider options that avoids breaking downstream usages of cargo on distributed `rustc-src` artifacts, where such cargo invocations fail due to inability to inherit `lints` from workspace root manifest's `workspace.lints` (this is only valid for the source rust-lang/rust workspace, but not really the distributed `rustc-src` artifacts). The problem is that the `rustc-src` component doesn't include the root `Cargo.toml` manifest.
This breakage was reported in https://github.com/rust-lang/rust/issues/138304.
This reverts commit 48caf81484, reversing changes made to c6662879b2.
cc `@RalfJung`
r? `@nnethercote` (sorry, I didn't consider this being a thing 💀)
Fix O(tests) stack usage in edition 2024 mergeable doctests
Fixes https://github.com/rust-lang/rust/issues/138248
The important change here is that we are not passing a potentially-large array by value. Between the fact that `TestFn` cannot be `Clone` and `test_main` takes a `Vec<TestDescAndFn>`, the only way to call `test::test_main` without O(tests) stack use is to call `Vec::push` many times.
The normal test harness does not have this problem because it calls `test_main_static` or `test_main_static_abort`, which take `&[TestDescAndFn]`. Changing `test::test_main` to take a slice is not a simple change, so I'm avoiding doing it here.
Fix post-merge workflow
I forgot that `actions/checkout` only checks out a single commit by default. I also forgot to set the environment variable required for the `gh` CLI commands.
I did a few more tests on my fork and hopefully now it should work properly. I also tested it with fake rollup PRs and the comment was sent only to the merged rollup, as it should be.
r? `@marcoieni`
Pass `InferCtxt` to `InlineAsmCtxt` to properly taint on error
Pass an `InferCtxt` into the `InlineAsmCtxt` so that we can use the right dcx to taint the infcx properly, so that we don't try to build invalid MIR for inline asm blocks.
Fixes#138130
Shares the first commit with #137502.
r? oli-obk
Revert <https://github.com/rust-lang/rust/pull/138084> to buy time to
consider options that avoids breaking downstream usages of cargo on
distributed `rustc-src` artifacts, where such cargo invocations fail due
to inability to inherit `lints` from workspace root manifest's
`workspace.lints` (this is only valid for the source rust-lang/rust
workspace, but not really the distributed `rustc-src` artifacts).
This breakage was reported in
<https://github.com/rust-lang/rust/issues/138304>.
This reverts commit 48caf81484, reversing
changes made to c6662879b2.
triagebot.toml: Don't label `test/rustdoc-json` as A-rustdoc-search (…
Followup to #137958. I managed to miss a place, as shown by the questionable labeling of #138285.
Fix dyn -> param suggestion in struct ICEs
Makes the logic from #138042 a bit less ICEy and more clean. Also fixes an incorrect suggestion when the struct already has generics. I'll point out the major changes and observations in the code.
Fixes#138229Fixes#138211
r? nnethercote since you reviewed the original pr, or re-roll if you don't want to review this
Support `File::seek` for Hermit
`lseek` was added in `hermit-abi` in commit [87dd201](87dd201a14) (add missing interface for lseek, 2024-07-15), which was just released in version 0.5.0.
cc ``@mkroening,`` ``@stlankes``
Fixes https://github.com/hermit-os/hermit-rs/issues/652
Add a test for `-znostart-stop-gc` usage with LLD
This test replicates the behavior of https://github.com/dtolnay/linkme, to test that it still works even with LLD. Without `-znostart-stop-gc` the test fails.
r? ``@lqd``
try-job: x86_64-gnu
try-job: x86_64-msvc-1
Update to rand 0.9.0
Changes include:
- `thread_rng` has been renamed to `rng`
- `Standard` has been renamed to `StandardUniform`
- `gen`, `gen_range`, `gen_bool` have been renamed to `random`, `random_range` and `random_bool` respectively.
Update cargo
22 commits in 2622e844bc1e2e6123e54e94e4706f7b6195ce3d..ab1463d632528e39daf35f263e10c14cbe590ce8
2025-02-28 12:33:57 +0000 to 2025-03-08 01:45:05 +0000
- test: redact host target when comparing CARGO_ENV path (rust-lang/cargo#15279)
- feat: add completions for install --path (rust-lang/cargo#15266)
- fix(package): report lockfile / workspace manifest is dirty (rust-lang/cargo#15276)
- feat(tree): Add `--depth public` behind `-Zunstable-options` (rust-lang/cargo#15243)
- Don't use `$CARGO_BUILD_TARGET` in `cargo metadata` (rust-lang/cargo#15271)
- feat: show extra build description from bootstrap (rust-lang/cargo#15269)
- Upgrade to `rustc-stable-hash v0.1.2` (rust-lang/cargo#15268)
- fix: Respect --frozen everywhere --offline or --locked is accepted (rust-lang/cargo#15263)
- feat(tree): Color the output (rust-lang/cargo#15242)
- fix(vendor): dont remove non-cached source (rust-lang/cargo#15260)
- docs: lockfile is always included since 1.84 (rust-lang/cargo#15257)
- Remove `Cargo.toml` from `package.include` in example (rust-lang/cargo#15253)
- Small cleanup: remove unneeded result (rust-lang/cargo#15256)
- Fix typo in build-scripts.md (rust-lang/cargo#15254)
- chore(deps): update rust crate pulldown-cmark to 0.13.0 (rust-lang/cargo#15250)
- chore(deps): update compatible (rust-lang/cargo#15249)
- feat(cli): forward bash completions of third party subcommands (rust-lang/cargo#15247)
- feat: add completions for `--lockfile-path` (rust-lang/cargo#15238)
- fix: reset $CARGO if the running program is real `cargo[.exe]` (rust-lang/cargo#15208)
- Get all members as `available targets` even though default-members was specified. (rust-lang/cargo#15199)
- refactor: control byte display precision with std::fmt options (rust-lang/cargo#15246)
- fix(package): Ensure we can package directories ending with '.rs' (rust-lang/cargo#15240)
std: move stdio to `sys`
As per #117276, this moves the platform definitions of `Stdout` and friends into `sys`. This PR also unifies the UNIX and Hermit implementations and moves the `__rust_print_err` function needed by libunwind on SGX into the dedicated module for such helper functions.
