Stabilize remaining integer methods as `const fn`
This pull request stabilizes the following methods as `const fn`:
- `i*::checked_div`
- `i*::checked_div_euclid`
- `i*::checked_rem`
- `i*::checked_rem_euclid`
- `i*::div_euclid`
- `i*::overflowing_div`
- `i*::overflowing_div_euclid`
- `i*::overflowing_rem`
- `i*::overflowing_rem_euclid`
- `i*::rem_euclid`
- `i*::wrapping_div`
- `i*::wrapping_div_euclid`
- `i*::wrapping_rem`
- `i*::wrapping_rem_euclid`
- `u*::checked_div`
- `u*::checked_div_euclid`
- `u*::checked_rem`
- `u*::checked_rem_euclid`
- `u*::div_euclid`
- `u*::overflowing_div`
- `u*::overflowing_div_euclid`
- `u*::overflowing_rem`
- `u*::overflowing_rem_euclid`
- `u*::rem_euclid`
- `u*::wrapping_div`
- `u*::wrapping_div_euclid`
- `u*::wrapping_rem`
- `u*::wrapping_rem_euclid`
These can all be implemented on the current stable (1.49). There are two unstable details: const likely/unlikely and unchecked division/remainder. Both of these are for optimizations, and are in no way required to make the methods function; there is no exposure of these details publicly. Per comments below, it seems best practice is to stabilize the intrinsics. As such, `intrinsics::unchecked_div` and `intrinsics::unchecked_rem` have been stabilized as `const` as part of this pull request as well. The methods themselves remain unstable.
I believe part of the reason these were not stabilized previously was the behavior around division by 0 and modulo 0. After testing on nightly, the diagnostic for something like `const _: i8 = 5i8 % 0i8;` is similar to that of `const _: i8 = 5i8.rem_euclid(0i8);` (assuming the appropriate feature flag is enabled). As such, I believe these methods are ready to be stabilized as `const fn`.
This pull request represents the final methods mentioned in #53718. As such, this PR closes#53718.
`@rustbot` modify labels to +A-const-fn, +T-libs
Implement `--extern-location`
This PR implements `--extern-location` as a followup to #72342 as part of the implementation of #57274. The goal of this PR is to allow rustc, in coordination with the build system, to present a useful diagnostic about how to remove an unnecessary dependency from a dependency specification file (eg Cargo.toml).
EDIT: Updated to current PR state.
The location is specified for each named crate - that is, for a given `--extern foo[=path]` there can also be `--extern-location foo=<location>`. It supports ~~three~~ two styles of location:
~~1. `--extern-location foo=file:<path>:<line>` - a file path and line specification
1. `--extern-location foo=span:<path>:<start>:<end>` - a span specified as a file and start and end byte offsets~~
1. `--extern-location foo=raw:<anything>` - a raw string which is included in the output
1. `--extern-location foo=json:<anything>` - an arbitrary Json structure which is emitted via Json diagnostics in a `tool_metadata` field.
~~1 & 2 are turned into an internal `Span`, so long as the path exists and is readable, and the location is meaningful (within the file, etc). This is used as the `Span` for a fix suggestion which is reported like other fix suggestions.~~
`raw` and `json` are for the case where the location isn't best expressed as a file and location within that file. For example, it could be a rule name and the name of a dependency within that rule. `rustc` makes no attempt to parse the raw string, and simply includes it in the output diagnostic text. `json` is only included in json diagnostics. `raw` is emitted as text and also as a json string in `tool_metadata`.
If no `--extern-location` option is specified then it will emit a default json structure consisting of `{"name": name, "path": path}` corresponding to the name and path in `--extern name=path`.
This is a prototype/RFC to make some of the earlier conversations more concrete. It doesn't stand on its own - it's only useful if implemented by Cargo and other build systems. There's also a ton of implementation details which I'd appreciate a second eye on as well.
~~**NOTE** The first commit in this PR is #72342 and should be ignored for the purposes of review. The first commit is a very simplistic implementation which is basically raw-only, presented as a MVP. The second implements the full thing, and subsequent commits are incremental fixes.~~
cc `@ehuss` `@est31` `@petrochenkov` `@estebank`
...so we can skip serializing `tool_metadata` if it hasn't been set.
This makes the output a bit cleaner, and avoiding having to update a
bunch of unrelated tests.
This allows a build system to indicate a location in its own dependency
specification files (eg Cargo's `Cargo.toml`) which can be reported
along side any unused crate dependency.
This supports several types of location:
- 'json' - provide some json-structured data, which is included in the json diagnostics
in a `tool_metadata` field
- 'raw' - emit the provided string into the output. This also appears as a json string in
`tool_metadata`.
If no `--extern-location` is explicitly provided then a default json entry of the form
`"tool_metadata":{"name":<cratename>,"path":<cratepath>}` is emitted.
Improve SIMD type element count validation
Resolvesrust-lang/stdsimd#53.
These changes are motivated by `stdsimd` moving in the direction of const generic vectors, e.g.:
```rust
#[repr(simd)]
struct SimdF32<const N: usize>([f32; N]);
```
This makes a few changes:
* Establishes a maximum SIMD lane count of 2^16 (65536). This value is arbitrary, but attempts to validate lane count before hitting potential errors in the backend. It's not clear what LLVM's maximum lane count is, but cranelift's appears to be much less than `usize::MAX`, at least.
* Expands some SIMD intrinsics to support arbitrary lane counts. This resolves the ICE in the linked issue.
* Attempts to catch invalid-sized vectors during typeck when possible.
Unresolved questions:
* Generic-length vectors can't be validated in typeck and are only validated after monomorphization while computing layout. This "works", but the errors simply bail out with no context beyond the name of the type. Should these errors instead return `LayoutError` or otherwise provide context in some way? As it stands, users of `stdsimd` could trivially produce monomorphization errors by making zero-length vectors.
cc `@bjorn3`
expand/resolve: Turn `#[derive]` into a regular macro attribute
This PR turns `#[derive]` into a regular attribute macro declared in libcore and defined in `rustc_builtin_macros`, like it was previously done with other "active" attributes in https://github.com/rust-lang/rust/pull/62086, https://github.com/rust-lang/rust/pull/62735 and other PRs.
This PR is also a continuation of #65252, #69870 and other PRs linked from them, which layed the ground for converting `#[derive]` specifically.
`#[derive]` still asks `rustc_resolve` to resolve paths inside `derive(...)`, and `rustc_expand` gets those resolution results through some backdoor (which I'll try to address later), but otherwise `#[derive]` is treated as any other macro attributes, which simplifies the resolution-expansion infra pretty significantly.
The change has several observable effects on language and library.
Some of the language changes are **feature-gated** by [`feature(macro_attributes_in_derive_output)`](https://github.com/rust-lang/rust/issues/81119).
#### Library
- `derive` is now available through standard library as `{core,std}::prelude::v1::derive`.
#### Language
- `derive` now goes through name resolution, so it can now be renamed - `use derive as my_derive; #[my_derive(Debug)] struct S;`.
- `derive` now goes through name resolution, so this resolution can fail in corner cases. Crater found one such regression, where import `use foo as derive` goes into a cycle with `#[derive(Something)]`.
- **[feature-gated]** `#[derive]` is now expanded as any other attributes in left-to-right order. This allows to remove the restriction on other macro attributes following `#[derive]` (https://github.com/rust-lang/reference/issues/566). The following macro attributes become a part of the derive's input (this is not a change, non-macro attributes following `#[derive]` were treated in the same way previously).
- `#[derive]` is now expanded as any other attributes in left-to-right order. This means two derive attributes `#[derive(Foo)] #[derive(Bar)]` are now expanded separately rather than together. It doesn't generally make difference, except for esoteric cases. For example `#[derive(Foo)]` can now produce an import bringing `Bar` into scope, but previously both `Foo` and `Bar` were required to be resolved before expanding any of them.
- **[feature-gated]** `#[derive()]` (with empty list in parentheses) actually becomes useful. For historical reasons `#[derive]` *fully configures* its input, eagerly evaluating `cfg` everywhere in its target, for example on fields.
Expansion infra doesn't do that for other attributes, but now when macro attributes attributes are allowed to be written after `#[derive]`, it means that derive can *fully configure* items for them.
```rust
#[derive()]
#[my_attr]
struct S {
#[cfg(FALSE)] // this field in removed by `#[derive()]` and not observed by `#[my_attr]`
field: u8
}
```
- `#[derive]` on some non-item targets is now prohibited. This was accidentally allowed as noop in the past, but was warned about since early 2018 (#50092), despite that crater found a few such cases in unmaintained crates.
- Derive helper attributes used before their introduction are now reported with a deprecation lint. This change is long overdue (since macro modularization, https://github.com/rust-lang/rust/issues/52226#issuecomment-422605033), but it was hard to do without fixing expansion order for derives. The deprecation is tracked by #79202.
```rust
#[trait_helper] // warning: derive helper attribute is used before it is introduced
#[derive(Trait)]
struct S {}
```
Crater analysis: https://github.com/rust-lang/rust/pull/79078#issuecomment-731436821
Identify unreachable subpatterns more reliably
In https://github.com/rust-lang/rust/pull/80104 I used `Span`s to identify unreachable sub-patterns in the presence of or-patterns during exhaustiveness checking. In https://github.com/rust-lang/rust/issues/80501 it was revealed that `Span`s are complicated and that this was not a good idea.
Instead, this PR identifies subpatterns logically: as a path in the tree of subpatterns of a given pattern. I made a struct that captures a set of such subpatterns. This is a bit complex, but thankfully self-contained; the rest of the code does not need to know anything about it.
Fixes https://github.com/rust-lang/rust/issues/80501. I think I managed to keep the perf neutral.
r? `@varkor`
Rollup of 5 pull requests
Successful merges:
- #81526 (btree: use Option's unwrap_unchecked())
- #81742 (Add a note about the correctness and the effect on unsafe code to the `ExactSizeIterator` docs)
- #81830 (Add long error explanation for E0542)
- #81835 (Improve long explanation for E0546)
- #81843 (Add regression test for #29821)
Failed merges:
- #81836 (Add long explanation for E0547)
r? `@ghost`
`@rustbot` modify labels: rollup
Add abi field to `Method`
Also bumps version and adds a test (Will conflict with #81500, whichever is merged first)
Rationale: It's possible for methods to have an ABI. This should be exposed in the JSON.
Add test for #75158
This also shifts some type-size related tests into a new directory, so that we keep the number of files at the root down.
Closes#75158
Add a test for escaping LLVMisms in inline asm
We escape certain LLVM-specific features when passing the inline
assembly string to the LLVM. Until now, however, there was no test
making sure this behaviour stays intact. This commit adds such a test!
r? `@Amanieu`
cc `@joshtriplett`
typeck: Emit structured suggestions for tuple struct syntax
And tuple variant syntax, but that didn't fit in the subject :)
Now the fact that these are suggestions is exposed both to the layout
engine and to IDEs and rustfix for automatic application.
We escape certain LLVM-specific features when passing the inline
assembly string to the LLVM. Until now, however, there was no test
making sure this behaviour stays intact. This commit adds such a test!
Make rustdoc respect `--error-format short` in doctests
Note that this will not work with `cargo test`, only with `rustdoc --test`, I'll have to modify `cargo` as well.
Fix#81662.
`@rustbot` label +T-rustdoc +A-doctests
Revert 78373 ("dont leak return value after panic in drop")
Short term resolution for issue #80949.
Reopen#47949 after this lands.
(We plan to fine-tune PR #78373 to not run into this problem.)
Remove struct_type from union output
Also bumps the format number and adds a test
Rationale: It's illegal to have unions of the form `union Union(i32, f32);`, or `union Union;`. The struct_type field was recently removed from the rustdoc Union AST, at which time this field was changed to always just read "union". It makes sense to completely remove it, as it provides no information.
rustdoc-json: Fix has_body
Previously, `has_body` was always true. Now propagate the type of the method to set it correctly. Relies on #81287, that will need to be merged first.
relax adt unsizing requirements
Changes unsizing of structs in case the last struct field shares generic params with other adt fields which do not change.
This change is currently insta stable and changes the language, so it at least requires a lang fcp. I feel like the current state is fairly unintuitive.
An example for what's now allowed would be https://play.rust-lang.org/?version=stable&mode=debug&edition=2018&gist=6dd331d23f5c9ffc8c978175aae2e967
```rust
struct A<T, U: ?Sized>(T, B<T, U>); // previously ERR
// struct A<T, U: ?Sized>(T, B<[u32; 1], U>); // ok
struct B<T, U: ?Sized>(T, U);
fn main() {
let x = A([0; 1], B([0; 1], [0; 1]));
let y: &A<[u32; 1], [u32]> = &x;
assert_eq!(y.1.1.len(), 1);
}
```
Use `# min-llvm-version: 11.0` to force a minimum LLVM version
Use `# min-llvm-version: 11.0` to force a minimum LLVM version, rather than ad-hoc internal solution.
In particular: the specific code to define LLVM_VERSION_11_PLUS here was, for some reason, using `$(shell ...)` with bash-specific variable replacement code. On non-bash platforms like dash, that `shell` invocation would fail, and the
LLVM_VERSION_11_PLUS check would always fail, the test would always be ignored, and thus be treated as a "success" (in the sense that `--bless` would never do anything).
* Note in particular that GNU Make treats the SHELL variable as a very special case: it does not inherit the value of SHELL from the user's environment. Except on Windows. See more explanation in the [GNU Make docs](https://www.gnu.org/software/make/manual/html_node/Choosing-the-Shell.html).
* The effect of this is that these tests end up using `/bin/sh` (except on Windows) for their `$(shell ...)` invocations, and thus we see differing behaviors depending on whether your `/bin/sh` links to `/bin/dash` or to `/bin/bash`.
This was causing me a lot of pain.
Move test to be with the others
No functional changes. I just created this test in the wrong place in a past PR. All of the other or-pattern tests are in the `or-patterns` directory.
