Uplift `EarlyBinder` into `rustc_type_ir`
We also need to give `EarlyBinder` a `'tcx` param, so that we can carry the `Interner` in the `EarlyBinder` too. This is necessary because otherwise we have an unconstrained `I: Interner` parameter in many of the `EarlyBinder`'s inherent impls.
I also generally think that this is desirable to have, in case we later want to track some state in the `EarlyBinder`.
r? lcnr
[perf] Delay the construction of early lint diag structs
Attacks some of the perf regressions from https://github.com/rust-lang/rust/pull/124417#issuecomment-2123700666.
See individual commits for details. The first three commits are not strictly necessary.
However, the 2nd one (06bc4fc671, *Remove `LintDiagnostic::msg`*) makes the main change way nicer to implement.
It's also pretty sweet on its own if I may say so myself.
Remove `DefId` from `EarlyParamRegion`
Currently we represent usages of `Region` parameters via the `ReEarlyParam` or `ReLateParam` variants. The `ReEarlyParam` is effectively equivalent to `TyKind::Param` and `ConstKind::Param` (i.e. it stores a `Symbol` and a `u32` index) however it also stores a `DefId` for the definition of the lifetime parameter.
This was used in roughly two places:
- Borrowck diagnostics instead of threading the appropriate `body_id` down to relevant locations. Interestingly there were already some places that had to pass down a `DefId` manually.
- Some opaque type checking logic was using the `DefId` field to track captured lifetimes
I've split this PR up into a commit for generate rote changes to diagnostics code to pass around a `DefId` manually everywhere, and another commit for the opaque type related changes which likely require more careful review as they might change the semantics of lints/errors.
Instead of manually passing the `DefId` around everywhere I previously tried to bundle it in with `TypeErrCtxt` but ran into issues with some call sites of `infcx.err_ctxt` being unable to provide a `DefId`, particularly places involved with trait solving and normalization. It might be worth investigating adding some new wrapper type to pass this around everywhere but I think this might be acceptable for now.
This pr also has the effect of reducing the size of `EarlyParamRegion` from 16 bytes -> 8 bytes. I wouldn't expect this to have any direct performance improvement however, other variants of `RegionKind` over `8` bytes are all because they contain a `BoundRegionKind` which is, as far as I know, mostly there for diagnostics. If we're ever able to remove this it would shrink the `RegionKind` type from `24` bytes to `12` (and with clever bit packing we might be able to get it to `8` bytes). I am curious what the performance impact would be of removing interning of `Region`'s if we ever manage to shrink `RegionKind` that much.
Sidenote: by removing the `DefId` the `Debug` output for `Region` has gotten significantly nicer. As an example see this opaque type debug print before vs after this PR:
`Opaque(DefId(0:13 ~ impl_trait_captures[aeb9]::foo::{opaque#0}), [DefId(0:9 ~ impl_trait_captures[aeb9]::foo::'a)_'a/#0, T, DefId(0:9 ~ impl_trait_captures[aeb9]::foo::'a)_'a/#0])`
`Opaque(DefId(0:13 ~ impl_trait_captures[aeb9]::foo::{opaque#0}), ['a/#0, T, 'a/#0])`
r? `@compiler-errors` (I would like someone who understands the opaque type setup to atleast review the type system commit, but the rest is likely reviewable by anyone)
Turn remaining non-structural-const-in-pattern lints into hard errors
This completes the implementation of https://github.com/rust-lang/rust/issues/120362 by turning our remaining future-compat lints into hard errors: indirect_structural_match and pointer_structural_match.
They have been future-compat lints for a while (indirect_structural_match for many years, pointer_structural_match since Rust 1.75 (released Dec 28, 2023)), and have shown up in dependency breakage reports since Rust 1.78 (just released on May 2, 2024). I don't expect a lot of code will still depend on them, but we will of course do a crater run.
A lot of cleanup is now possible in const_to_pat, but that is deferred to a later PR.
Fixes https://github.com/rust-lang/rust/issues/70861
Run rustfmt on files that need it.
Somehow these files aren't properly formatted. By default `x fmt` and `x tidy` only check files that have changed against master, so if an ill-formatted file somehow slips in it can stay that way as long as it doesn't get modified(?)
I found these when I ran `x fmt` explicitly on every `.rs` file in the repo, while working on
https://github.com/rust-lang/compiler-team/issues/750.
Somehow these files aren't properly formatted. By default `x fmt` and `x
tidy` only check files that have changed against master, so if an
ill-formatted file somehow slips in it can stay that way as long as it
doesn't get modified(?)
I found these when I ran `x fmt` explicitly on every `.rs` file in the
repo, while working on
https://github.com/rust-lang/compiler-team/issues/750.
Rollup of 6 pull requests
Successful merges:
- #125263 (rust-lld: fallback to rustc's sysroot if there's no path to the linker in the target sysroot)
- #125345 (rustc_codegen_llvm: add support for writing summary bitcode)
- #125362 (Actually use TAIT instead of emulating it)
- #125412 (Don't suggest adding the unexpected cfgs to the build-script it-self)
- #125445 (Migrate `run-make/rustdoc-with-short-out-dir-option` to `rmake.rs`)
- #125452 (Cleanup check-cfg handling in core and std)
r? `@ghost`
`@rustbot` modify labels: rollup
Don't suggest adding the unexpected cfgs to the build-script it-self
This PR adds a check to avoid suggesting to add the unexpected cfgs inside the build-script when building the build-script it-self, as it won't have any effect, since build-scripts applies to their descended target.
Fixes#125368
Remove more `#[macro_use] extern crate tracing`
Because explicit importing of macros via use items is nicer (more standard and readable) than implicit importing via `#[macro_use]`. Continuing the work from #124511 and #124914.
r? `@jackh726`
Use correct param-env in `MissingCopyImplementations`
We shouldn't assume the param-env is empty for this lint, since although we check the struct has no parameters, there still may be trivial where-clauses.
fixes#125394
Cleanup: Fix up some diagnostics
Several diagnostics contained their error code inside their primary message which is no bueno.
This PR moves them out of the message and turns them into structured error codes.
Also fixes another occurrence of `->` after a selector in a Fluent message which is not correct. I've fixed two other instances of this issue in #104345 (2022) but didn't update all instances as I've noted here: https://github.com/rust-lang/rust/pull/104345#issuecomment-1312705977 (“the future is now!”).
Expand `for_loops_over_fallibles` lint to lint on fallibles behind references.
Extends the scope of the (warn-by-default) lint `for_loops_over_fallibles` from just `for _ in x` where `x: Option<_>/Result<_, _>` to also cover `x: &(mut) Option<_>/Result<_>`
```rs
fn main() {
// Current lints
for _ in Some(42) {}
for _ in Ok::<_, i32>(42) {}
// New lints
for _ in &Some(42) {}
for _ in &mut Some(42) {}
for _ in &Ok::<_, i32>(42) {}
for _ in &mut Ok::<_, i32>(42) {}
// Should not lint
for _ in Some(42).into_iter() {}
for _ in Some(42).iter() {}
for _ in Some(42).iter_mut() {}
for _ in Ok::<_, i32>(42).into_iter() {}
for _ in Ok::<_, i32>(42).iter() {}
for _ in Ok::<_, i32>(42).iter_mut() {}
}
```
<details><summary><code>cargo build</code> diff</summary>
```diff
diff --git a/old.out b/new.out
index 84215aa..ca195a7 100644
--- a/old.out
+++ b/new.out
`@@` -1,33 +1,93 `@@`
warning: for loop over an `Option`. This is more readably written as an `if let` statement
--> src/main.rs:3:14
|
3 | for _ in Some(42) {}
| ^^^^^^^^
|
= note: `#[warn(for_loops_over_fallibles)]` on by default
help: to check pattern in a loop use `while let`
|
3 | while let Some(_) = Some(42) {}
| ~~~~~~~~~~~~~~~ ~~~
help: consider using `if let` to clear intent
|
3 | if let Some(_) = Some(42) {}
| ~~~~~~~~~~~~ ~~~
warning: for loop over a `Result`. This is more readably written as an `if let` statement
--> src/main.rs:4:14
|
4 | for _ in Ok::<_, i32>(42) {}
| ^^^^^^^^^^^^^^^^
|
help: to check pattern in a loop use `while let`
|
4 | while let Ok(_) = Ok::<_, i32>(42) {}
| ~~~~~~~~~~~~~ ~~~
help: consider using `if let` to clear intent
|
4 | if let Ok(_) = Ok::<_, i32>(42) {}
| ~~~~~~~~~~ ~~~
-warning: `for-loops-over-fallibles` (bin "for-loops-over-fallibles") generated 2 warnings
- Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.04s
+warning: for loop over a `&Option`. This is more readably written as an `if let` statement
+ --> src/main.rs:7:14
+ |
+7 | for _ in &Some(42) {}
+ | ^^^^^^^^^
+ |
+help: to check pattern in a loop use `while let`
+ |
+7 | while let Some(_) = &Some(42) {}
+ | ~~~~~~~~~~~~~~~ ~~~
+help: consider using `if let` to clear intent
+ |
+7 | if let Some(_) = &Some(42) {}
+ | ~~~~~~~~~~~~ ~~~
+
+warning: for loop over a `&mut Option`. This is more readably written as an `if let` statement
+ --> src/main.rs:8:14
+ |
+8 | for _ in &mut Some(42) {}
+ | ^^^^^^^^^^^^^
+ |
+help: to check pattern in a loop use `while let`
+ |
+8 | while let Some(_) = &mut Some(42) {}
+ | ~~~~~~~~~~~~~~~ ~~~
+help: consider using `if let` to clear intent
+ |
+8 | if let Some(_) = &mut Some(42) {}
+ | ~~~~~~~~~~~~ ~~~
+
+warning: for loop over a `&Result`. This is more readably written as an `if let` statement
+ --> src/main.rs:9:14
+ |
+9 | for _ in &Ok::<_, i32>(42) {}
+ | ^^^^^^^^^^^^^^^^^
+ |
+help: to check pattern in a loop use `while let`
+ |
+9 | while let Ok(_) = &Ok::<_, i32>(42) {}
+ | ~~~~~~~~~~~~~ ~~~
+help: consider using `if let` to clear intent
+ |
+9 | if let Ok(_) = &Ok::<_, i32>(42) {}
+ | ~~~~~~~~~~ ~~~
+
+warning: for loop over a `&mut Result`. This is more readably written as an `if let` statement
+ --> src/main.rs:10:14
+ |
+10 | for _ in &mut Ok::<_, i32>(42) {}
+ | ^^^^^^^^^^^^^^^^^^^^^
+ |
+help: to check pattern in a loop use `while let`
+ |
+10 | while let Ok(_) = &mut Ok::<_, i32>(42) {}
+ | ~~~~~~~~~~~~~ ~~~
+help: consider using `if let` to clear intent
+ |
+10 | if let Ok(_) = &mut Ok::<_, i32>(42) {}
+ | ~~~~~~~~~~ ~~~
+
+warning: `for-loops-over-fallibles` (bin "for-loops-over-fallibles") generated 6 warnings
+ Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.02s
```
</details>
-----
Question:
* ~~Currently, the article `an` is used for `&Option`, and `&mut Option` in the lint diagnostic, since that's what `Option` uses. Is this okay or should it be changed? (likewise, `a` is used for `&Result` and `&mut Result`)~~ The article `a` is used for `&Option`, `&mut Option`, `&Result`, `&mut Result` and (as before) `Result`. Only `Option` uses `an` (as before).
`@rustbot` label +A-lint
* instead simply set the primary message inside the lint decorator functions
* it used to be this way before [#]101986 which introduced `msg` to prevent
good path delayed bugs (which no longer exist) from firing under certain
circumstances when lints were suppressed / silenced
* this is no longer necessary for various reasons I presume
* it shaves off complexity and makes further changes easier to implement
Translation of the lint message happens when the actual diagnostic is
created, not when the lint is buffered. Generating the message from
BuiltinLintDiag ensures that all required data to construct the message
is preserved in the LintBuffer, eventually allowing the messages to be
moved to fluent.
Remove the `msg` field from BufferedEarlyLint, it is either generated
from the data in the BuiltinLintDiag or stored inside
BuiltinLintDiag::Normal.
Update `unexpected_cfgs` lint for Cargo new `check-cfg` config
This PR updates the diagnostics output of the `unexpected_cfgs` lint for Cargo new `check-cfg` config.
It's a simple and cost-less alternative to the build-script `cargo::rustc-check-cfg` instruction.
```toml
[lints.rust]
unexpected_cfgs = { level = "warn", check-cfg = ['cfg(foo, values("bar"))'] }
```
This PR also adds a Cargo specific section regarding check-cfg and Cargo inside rustc's book (motivation is described inside the file, but mainly check-cfg is a rustc feature not a Cargo one, Cargo only enabled the feature, it does not own it; T-cargo even considers the `check-cfg` lint config to be an implementation detail).
This PR also updates the links to refer to that sub-page when using Cargo from rustc.
As well as updating the lint doc to refer to the check-cfg docs.
~**Not to be merged before https://github.com/rust-lang/cargo/pull/13913 reaches master!**~ (EDIT: merged in https://github.com/rust-lang/rust/pull/125237)
`@rustbot` label +F-check-cfg
r? `@fmease` *(feel free to roll)*
Fixes https://github.com/rust-lang/rust/issues/124800
cc `@epage` `@weihanglo`
chore: Remove repeated words (extension of #124924)
When I saw #124924 I thought "Hey, I'm sure that there are far more than just two typos of this nature in the codebase". So here's some more typo-fixing.
Some found with regex, some found with a spellchecker. Every single one manually reviewed by me (along with hundreds of false negatives by the tools)
Rename Unsafe to Safety
Alternative to #124455, which is to just have one Safety enum to use everywhere, this opens the posibility of adding `ast::Safety::Safe` that's useful for unsafe extern blocks.
This leaves us today with:
```rust
enum ast::Safety {
Unsafe(Span),
Default,
// Safe (going to be added for unsafe extern blocks)
}
enum hir::Safety {
Unsafe,
Safe,
}
```
We would convert from `ast::Safety::Default` into the right Safety level according the context.
Fix, document, and test parser and pretty-printer edge cases related to braced macro calls
_Review note: this is a deceptively small PR because it comes with 145 lines of docs and 196 lines of tests, and only 25 lines of compiler code changed. However, I recommend reviewing it 1 commit at a time because much of the effect of the code changes is non-local i.e. affecting code that is not visible in the final state of the PR. I have paid attention that reviewing the PR one commit at a time is as easy as I can make it. All of the code you need to know about is touched in those commits, even if some of those changes disappear by the end of the stack._
This is a follow-up to https://github.com/rust-lang/rust/pull/119105. One case that is not relevant to `-Zunpretty=expanded`, but which came up as I'm porting #119105 and #118726 into `syn`'s printer and `prettyplease`'s printer where it **is** relevant, and is also relevant to rustc's `stringify!`, is statement boundaries in the vicinity of braced macro calls.
Rustc's AST pretty-printer produces invalid syntax for statements that begin with a braced macro call:
```rust
macro_rules! stringify_item {
($i:item) => {
stringify!($i)
};
}
macro_rules! repro {
($e:expr) => {
stringify_item!(fn main() { $e + 1; })
};
}
fn main() {
println!("{}", repro!(m! {}));
}
```
**Before this PR:** output is not valid Rust syntax.
```console
fn main() { m! {} + 1; }
```
```console
error: leading `+` is not supported
--> <anon>:1:19
|
1 | fn main() { m! {} + 1; }
| ^ unexpected `+`
|
help: try removing the `+`
|
1 - fn main() { m! {} + 1; }
1 + fn main() { m! {} 1; }
|
```
**After this PR:** valid syntax.
```console
fn main() { (m! {}) + 1; }
```
This commit by itself is supposed to have no effect on behavior. All of
the call sites are updated to preserve their previous behavior.
The behavior changes are in the commits that follow.
For each of these, we need to decide whether they need to be using
`expr_requires_semi_to_be_stmt`, or `expr_requires_comma_to_be_match_arm`,
which are supposed to be 2 different behaviors. Previously they were
conflated into one, causing either too much or too little
parenthesization.
`InferCtxt::next_{ty,const}_var*` all take an origin, but the
`param_def_id` is almost always `None`. This commit changes them to just
take a `Span` and build the origin within the method, and adds new
methods for the rare cases where `param_def_id` might not be `None`.
This avoids a lot of tedious origin building.
Specifically:
- next_ty_var{,_id_in_universe,_in_universe}: now take `Span` instead of
`TypeVariableOrigin`
- next_ty_var_with_origin: added
- next_const_var{,_in_universe}: takes Span instead of ConstVariableOrigin
- next_const_var_with_origin: added
- next_region_var, next_region_var_in_universe: these are unchanged,
still take RegionVariableOrigin
The API inconsistency (ty/const vs region) seems worth it for the
large conciseness improvements.
Handle field projections like slice indexing in invalid_reference_casting
r? `@Urgau`
I saw the implementation in https://github.com/rust-lang/rust/pull/124761, and I was wondering if we also need to handle field access. We do. Without this PR, we get this errant diagnostic:
```
error: casting references to a bigger memory layout than the backing allocation is undefined behavior, even if the reference is unused
--> /home/ben/rust/tests/ui/lint/reference_casting.rs:262:18
|
LL | let r = &mut v.0;
| --- backing allocation comes from here
LL | let ptr = r as *mut i32 as *mut Vec3<i32>;
| ------------------------------- casting happend here
LL | unsafe { *ptr = Vec3(0, 0, 0) }
| ^^^^^^^^^^^^^^^^^^^^
|
= note: casting from `i32` (4 bytes) to `Vec3<i32>` (12 bytes)
```
Remove braces when fixing a nested use tree into a single item
[Back in 2019](https://github.com/rust-lang/rust/pull/56645) I added rustfix support for the `unused_imports` lint, to automatically remove them when running `cargo fix`. For the most part this worked great, but when removing all but one childs of a nested use tree it turned `use foo::{Unused, Used}` into `use foo::{Used}`. This is slightly annoying, because it then requires you to run `rustfmt` to get `use foo::Used`.
This PR automatically removes braces and the surrouding whitespace when all but one child of a nested use tree are unused. To get it done I had to add the span of the nested use tree to the AST, and refactor a bit the code I wrote back then.
A thing I noticed is, there doesn't seem to be any `//@ run-rustfix` test for fixing the `unused_imports` lint. I created a test in `tests/suggestions` (is that the right directory?) that for now tests just what I added in the PR. I can followup in a separate PR to add more tests for fixing `unused_lints`.
This PR is best reviewed commit-by-commit.
Fix insufficient logic when searching for the underlying allocation
This PR fixes the logic inside the `invalid_reference_casting` lint, when trying to lint on bigger memory layout casts.
More specifically when looking for the "underlying allocation" we were wrongly assuming that when we got `&mut slice[index]` that `slice[index]` was the allocation, but it's not.
Fixes https://github.com/rust-lang/rust/issues/124685
Some hir cleanups
It seemed odd to not put `AnonConst` in the arena, compared with the other types that we did put into an arena. This way we can also give it a `Span` without growing a lot of other HIR data structures because of the extra field.
r? compiler
Use `tcx.types.unit` instead of `Ty::new_unit(tcx)`
I don't think there is any need for the function, given that we can just access the `.types`, similarly to all other primitives?
Adjust `#[macro_export]`/doctest help suggestion for non_local_defs lint
This PR adjust the help suggestion of the `non_local_definitions` lint when encountering a `#[macro_export]` at top-level doctest.
So instead of a non-sentential help suggestion to move the `macro_rules!` up above the `rustdoc`-generated function. We now suggest users to declare their own function.
Fixes *(partially, needs backport)* #124534
Remove many `#[macro_use] extern crate foo` items
This requires the addition of more `use` items, which often make the code more verbose. But they also make the code easier to read, because `#[macro_use]` obscures where macros are defined.
r? `@fee1-dead`
[Refactor] Rename `Lint` and `LintGroup`'s `is_loaded` to `is_externally_loaded`
The field being named `is_loaded` was very confusing. Turns out it's true for lints that are registered by external tools like Clippy (I had to look at https://github.com/rust-lang/rust/pull/116412 to know what the variable meant). So I renamed `is_loaded` to `is_externally_loaded` and added some docs.
Couldn't find documentation supporting that single-variant
`#[repr(Rust)]` enums with RHS assigned work as expected with this
change.
```rust
enum Variants {
A = 17,
} // Would this be zero sized optimized guaranteed?
```
panic_str only exists for the migration to 2021 panic macros
The only caller is `expect_failed`, which is already a cold inline(never) function, so inlining into that function should be fine. (And indeed `panic_str` was `#[inline]` anyway.)
The existence of panic_str risks someone calling it when they should call `panic` instead, and I can't see a reason why this footgun should exist.
I also extended the comment in `panic` to explain why it needs a `'static` string -- I know I've wondered about this in the past and it took me quite a while to understand.
Rollup of 7 pull requests
Successful merges:
- #123680 (Deny gen keyword in `edition_2024_compat` lints)
- #124057 (Fix ICE when ADT tail has type error)
- #124168 (Use `DefiningOpaqueTypes::Yes` in rustdoc, where the `InferCtxt` is guaranteed to have no opaque types it can define)
- #124197 (Move duplicated code in functions in `tests/rustdoc-gui/notable-trait.goml`)
- #124200 (Improve handling of expr->field errors)
- #124220 (Miri: detect wrong vtables in wide pointers)
- #124266 (remove an unused type from the reentrant lock tests)
r? `@ghost`
`@rustbot` modify labels: rollup
Deny gen keyword in `edition_2024_compat` lints
Splits the `keyword_idents` lint into two -- `keyword_idents_2018` and `keyword_idents_2024` -- since each corresponds to a future-compat warning in a different edition. Group these together into a new `keyword_idents` lint group, and add the latter to the `rust_2024_compatibility` so that `gen` is ready for the 2024 edition.
cc `@traviscross` `@ehuss`
Fix trait solver overflow with `non_local_definitions` lint
This PR fixes the trait solver overflow with the `non_local_definitions` lint reported in https://github.com/rust-lang/rust/issues/123573 using the suggestion from `@lcnr:` https://github.com/rust-lang/rust/issues/123573#issuecomment-2041348320 to use the next trait solver.
~~I have not (yet) tried to create a minimized repro~~ ``@compiler-errors`` did the minimization (thanks you) but I have manually tested on the `starlark-rust` project that it fixes the issue.
Fixes#123573
r? `@lcnr`
Stabilize checking of cfgs at compile-time: `--check-cfg` option
This PR stabilize the `--check-cfg` CLI option of `rustc` (and `rustdoc`) 🎉.
In particular this PR does two things:
1. it makes the `--check-cfg` option stable
2. and it moves the documentation to the stable books
FCP: https://github.com/rust-lang/rust/issues/82450#issuecomment-1965328542Resolves#82450
``@rustbot`` labels +S-blocked +F-check-cfg
r? ``@petrochenkov``
Implement syntax for `impl Trait` to specify its captures explicitly (`feature(precise_capturing)`)
Implements `impl use<'a, 'b, T, U> Sized` syntax that allows users to explicitly list the captured parameters for an opaque, rather than inferring it from the opaque's bounds (or capturing *all* lifetimes under 2024-edition capture rules). This allows us to exclude some implicit captures, so this syntax may be used as a migration strategy for changes due to #117587.
We represent this list of captured params as `PreciseCapturingArg` in AST and HIR, resolving them between `rustc_resolve` and `resolve_bound_vars`. Later on, we validate that the opaques only capture the parameters in this list.
We artificially limit the feature to *require* mentioning all type and const parameters, since we don't currently have support for non-lifetime bivariant generics. This can be relaxed in the future.
We also may need to limit this to require naming *all* lifetime parameters for RPITIT, since GATs have no variance. I have to investigate this. This can also be relaxed in the future.
r? `@oli-obk`
Tracking issue:
- https://github.com/rust-lang/rust/issues/123432
Skip `unused_parens` report for `Paren(Path(..))` in macro.
fixes#120642
In following code, `unused_parens` suggest change `<($($rest),*)>::bar()` to `<$rest>::bar()` which will cause another err: `error: variable 'rest' is still repeating at this depth`：
```rust
trait Foo {
fn bar();
}
macro_rules! problem {
($ty:ident) => {
impl<$ty: Foo> Foo for ($ty,) {
fn bar() { <$ty>::bar() }
}
};
($ty:ident $(, $rest:ident)*) => {
impl<$ty: Foo, $($rest: Foo),*> Foo for ($ty, $($rest),*) {
fn bar() {
<$ty>::bar();
<($($rest),*)>::bar()
}
}
problem!($($rest),*);
}
}
```
I think maybe we can handle this by avoid warning for `Paren(Path(..))` in the macro. Is this reasonable approach?
Implement minimal, internal-only pattern types in the type system
rebase of https://github.com/rust-lang/rust/pull/107606
You can create pattern types with `std::pat::pattern_type!(ty is pat)`. The feature is incomplete and will panic on you if you use any pattern other than integral range patterns. The only way to create or deconstruct a pattern type is via `transmute`.
This PR's implementation differs from the MCP's text. Specifically
> This means you could implement different traits for different pattern types with the same base type. Thus, we just forbid implementing any traits for pattern types.
is violated in this PR. The reason is that we do need impls after all in order to make them usable as fields. constants of type `std::time::Nanoseconds` struct are used in patterns, so the type must be structural-eq, which it only can be if you derive several traits on it. It doesn't need to be structural-eq recursively, so we can just manually implement the relevant traits on the pattern type and use the pattern type as a private field.
Waiting on:
* [x] move all unrelated commits into their own PRs.
* [x] fix niche computation (see 2db07f94f44f078daffe5823680d07d4fded883f)
* [x] add lots more tests
* [x] T-types MCP https://github.com/rust-lang/types-team/issues/126 to finish
* [x] some commit cleanup
* [x] full self-review
* [x] remove 61bd325da19a918cc3e02bbbdce97281a389c648, it's not necessary anymore I think.
* [ ] ~~make sure we never accidentally leak pattern types to user code (add stability checks or feature gate checks and appopriate tests)~~ we don't even do this for the new float primitives
* [x] get approval that [the scope expansion to trait impls](https://rust-lang.zulipchat.com/#narrow/stream/326866-t-types.2Fnominated/topic/Pattern.20types.20types-team.23126/near/427670099) is ok
r? `@BoxyUwU`
Add consistency with phrases "meantime" and "mean time"
"mean time" is used in a few places while "meantime" is used everywhere else; this would make usage consistent throughout the codebase.
Add detection of [Partial]Ord methods in the `ambiguous_wide_pointer_comparisons` lint
Partially addresses https://github.com/rust-lang/rust/issues/121264 by adding diagnostics items for PartialOrd and Ord methods, detecting such diagnostics items as "binary operation" and suggesting the correct replacement.
I also took the opportunity to change the suggestion to use new methods `.cast()` on `*mut T` an d `*const T`.
Rename `hir::Local` into `hir::LetStmt`
Follow-up of #122776.
As discussed on [zulip](https://rust-lang.zulipchat.com/#narrow/stream/131828-t-compiler/topic/Improve.20naming.20of.20.60ExprKind.3A.3ALet.60.3F).
I made this change into a separate PR because I'm less sure about this change as is. For example, we have `visit_local` and `LocalSource` items. Is it fine to keep these two as is (I supposed it is but I prefer to ask) or not? Having `Node::Local(LetStmt)` makes things more explicit but is it going too far?
r? ```@oli-obk```
Rollup of 8 pull requests
Successful merges:
- #114009 (compiler: allow transmute of ZST arrays with generics)
- #122195 (Note that the caller chooses a type for type param)
- #122651 (Suggest `_` for missing generic arguments in turbofish)
- #122784 (Add `tag_for_variant` query)
- #122839 (Split out `PredicatePolarity` from `ImplPolarity`)
- #122873 (Merge my contributor emails into one using mailmap)
- #122885 (Adjust better spastorino membership to triagebot's adhoc_groups)
- #122888 (add a couple more tests)
r? `@ghost`
`@rustbot` modify labels: rollup
