Remove support for specializing ToString outside the standard library
This is the only trait specializable outside of the standard library. Before stabilizing specialization we will probably want to remove support for this. It was originally made specializable to allow a more efficient ToString in libproc_macro back when this way the only way to get any data out of a TokenStream. We now support getting individual tokens, so proc macros no longer need to call it as often.
the linker arguments can be *very* long, especially for crates with many dependencies. some parts of them are not very useful. unless specifically requested:
- omit object files specific to the current invocation
- fold rlib files into a single braced argument (in shell expansion format)
this shortens the output significantly without removing too much information.
Rollup of 7 pull requests
Successful merges:
- #132939 (Suggest using deref in patterns)
- #133293 (Updates Solaris target information, adds Solaris maintainer)
- #133392 (Fix ICE when multiple supertrait substitutions need assoc but only one is provided)
- #133986 (Add documentation for anonymous pipe module)
- #134022 (Doc: Extend for tuples to be stabilized in 1.85.0)
- #134259 (Clean up `infer_return_ty_for_fn_sig`)
- #134264 (Arbitrary self types v2: Weak & NonNull diagnostics)
r? `@ghost`
`@rustbot` modify labels: rollup
Arbitrary self types v2: Weak & NonNull diagnostics
This builds on top of #134262 which is more urgent to review and merge first. I'll likely rebase this PR once that lands.
This is the first part of the diagnostic enhancements planned for Arbitrary Self Types v2.
Various types can be used as method receivers, such as `Rc<>`, `Box<>` and `Arc<>`. The arbitrary self types v2 work allows further types to be made method receivers by implementing the Receiver trait.
With that in mind, it may come as a surprise to people when certain common types do not implement Receiver and thus cannot be used as a method receiver.
The RFC for arbitrary self types v2 therefore proposes emitting specific
lint hints for these cases:
* `NonNull`
* `Weak`
* Raw pointers
The code already emits a hint for this third case, in that it advises folks that the `arbitrary_self_types_pointers` feature may meet their need. This PR adds diagnostic hints for the `Weak` and `NonNull` cases.
Tracking issue #44874
r? `@wesleywiser`
Fix ICE when multiple supertrait substitutions need assoc but only one is provided
Dyn traits must have all of their associated types constrained either by:
1. writing them in the dyn trait itself as an associated type bound, like `dyn Iterator<Item = u32>`,
2. A supertrait bound, like `trait ConstrainedIterator: Iterator<Item = u32> {}`, then you may write `dyn ConstrainedIterator` which doesn't need to mention `Item`.
However, the object type lowering code did not consider the fact that there may be multiple supertraits with different substitutions, so it just used the associated type's *def id* as a key for keeping track of which associated types are missing:
1fc691e6dd/compiler/rustc_hir_analysis/src/hir_ty_lowering/dyn_compatibility.rs (L131)
This means that we can have missing associated types when there are mutliple supertraits with different substitutions and only one of them is constrained, like:
```rust
trait Sup<T> {
type Assoc: Default;
}
impl<T: Default> Sup<T> for () {
type Assoc = T;
}
impl<T: Default, U: Default> Dyn<T, U> for () {}
trait Dyn<A, B>: Sup<A, Assoc = A> + Sup<B> {}
```
The above example allows you to name `<dyn Dyn<i32, u32> as Sup<u32>>::Assoc` even though it is not possible to project since it's neither constrained by a manually written projection bound or a supertrait bound. This successfully type-checks, but leads to a codegen ICE since we are not able to project the associated type.
This PR fixes the validation for checking that a dyn trait mentions all of its associated type bounds. This is theoretically a breaking change, since you could technically use that `dyn Dyn<A, B>` type mentionedin the example above without actually *projecting* to the bad associated type, but I don't expect it to ever be relevant to a user since it's almost certainly a bug. This is corroborated with the crater results[^crater], which show no failures[^unknown].
Crater: https://github.com/rust-lang/rust/pull/133392#issuecomment-2508769703Fixes#133388
[^crater]: I cratered this originally with #133397, which is a PR that is stacked on top, then re-ran crater with just the failures from that PR.
[^unknown]: If you look at the crater results, it shows all of the passes as "unknown". I believe this is a crater bug, since looking at the results manually shows them as passes.
Suggest using deref in patterns
Fixes#132784
This changes the following code:
```rs
use std::sync::Arc;
fn main() {
let mut x = Arc::new(Some(1));
match x {
Some(_) => {}
None => {}
}
}
```
to output
```rs
error[E0308]: mismatched types
--> src/main.rs:5:9
|
LL | match x {
| - this expression has type `Arc<Option<{integer}>>`
...
LL | Some(_) => {}
| ^^^^^^^ expected `Arc<Option<{integer}>>`, found `Option<_>`
|
= note: expected struct `Arc<Option<{integer}>>`
found enum `Option<_>`
help: consider dereferencing to access the inner value using the Deref trait
|
LL | match *x {
| ~~
```
instead of
```rs
error[E0308]: mismatched types
--> src/main.rs:5:9
|
4 | match x {
| - this expression has type `Arc<Option<{integer}>>`
5 | Some(_) => {}
| ^^^^^^^ expected `Arc<Option<{integer}>>`, found `Option<_>`
|
= note: expected struct `Arc<Option<{integer}>>`
found enum `Option<_>`
```
This makes it more obvious that a Deref is available, and gives a suggestion on how to use it in order to fix the issue at hand.
Bounds-check with PtrMetadata instead of Len in MIR
Rather than emitting `Len(*_n)` in array index bounds checks, emit `PtrMetadata(copy _n)` instead -- with some asterisks for arrays and `&mut` that need it to be done slightly differently.
We're getting pretty close to removing `Len` entirely, actually. I think just one more PR after this (for slice drop shims).
r? mir
Various types can be used as method receivers, such as Rc<>, Box<> and
Arc<>. The arbitrary self types v2 work allows further types to be made
method receivers by implementing the Receiver trait.
With that in mind, it may come as a surprise to people when certain
common types do not implement Receiver and thus cannot be used as a
method receiver.
The RFC for arbitrary self types v2 therefore proposes emitting specific
lint hints for these cases:
* NonNull
* Weak
* Raw pointers
The code already emits a hint for this third case, in that it advises
folks that the `arbitrary_self_types_pointers` feature may meet their
need. This PR adds diagnostic hints for the Weak and NonNull cases.
Rollup of 6 pull requests
Successful merges:
- #133221 (Add external macros specific diagnostics for check-cfg)
- #133386 (Update linux_musl base to dynamically link the crt by default)
- #134191 (Make some types and methods related to Polonius + Miri public)
- #134227 (Update wasi-sdk used to build WASI targets)
- #134279 ((Re-)return adjustment target if adjust kind is never-to-any)
- #134295 (Encode coroutine-closures in SMIR)
r? `@ghost`
`@rustbot` modify labels: rollup
(Re-)return adjustment target if adjust kind is never-to-any
This PR fixes#134162 where we ICE'd on
```rs
fn main() {
struct X;
let _ = [X] == [panic!(); 2];
}
```
In https://github.com/rust-lang/rust/pull/121208#discussion_r1494187622, there was a change
```diff
- if let Some(adjustments) = self.typeck_results.borrow().adjustments().get(expr.hir_id) {
- let reported = self.dcx().span_delayed_bug(
- expr.span,
- "expression with never type wound up being adjusted",
- );
- return if let [Adjustment { kind: Adjust::NeverToAny, target }] = &adjustments[..] {
- target.to_owned()
- } else {
- Ty::new_error(self.tcx(), reported)
- };
- }
+ if let Some(_) = self.typeck_results.borrow().adjustments().get(expr.hir_id) {
+ self.dcx()
+ .span_bug(expr.span, "expression with never type wound up being adjusted");
+ }
```
It turned out returning the adjustment target if the adjustment kind is `NeverToAny` is necessary, as otherwise we will go through a series of `delay_bug`s and eventually find that we constructed a `TyKind::Error` without having actually emitted an error.
This PR addresses that by re-returning the adjustment target if the adjustment kind is `NeverToAny`, partially reverting this change from #121208.
This PR has two commits:
1. The first commit adds a regression test for #134162, which will ICE (on stable 1.83.0, beta and nightly 2024-12-13).
2. The second commit is the partial revert, which will fix the ICE.
cc `@nnethercote` FYI as this is related to #121208 changes. The changes from #121208 exposed that we lacked test coverage for the code pattern reported in #134162.
Update linux_musl base to dynamically link the crt by default
However, don't change the behavior of any existing targets at this time. For targets that used the old default, explicitly set `crt_static_default = true`.
This makes it easier for new targets to use the correct defaults while leaving the changing of individual targets to future PRs.
Related to https://github.com/rust-lang/compiler-team/issues/422
Add external macros specific diagnostics for check-cfg
This PR adds specific check-cfg diagnostics for unexpected cfg in external macros.
As well as hiding the some of the Cargo specific help/suggestions as they distraction for external macros and are generally not the right solution.
Follow-up to #132577
`@rustbot` label +L-unexpected_cfgs
r? compiler
Rollup of 6 pull requests
Successful merges:
- #132150 (Fix powerpc64 big-endian FreeBSD ABI)
- #133942 (Clarify how to use `black_box()`)
- #134081 (Try to evaluate constants in legacy mangling)
- #134192 (Remove `Lexer`'s dependency on `Parser`.)
- #134208 (coverage: Tidy up creation of covmap and covfun records)
- #134211 (On Neutrino QNX, reduce the need to set archiver via environment variables)
r? `@ghost`
`@rustbot` modify labels: rollup
(Re-)Implement `impl_trait_in_bindings`
This reimplements the `impl_trait_in_bindings` feature for local bindings.
"`impl Trait` in bindings" serve as a form of *trait* ascription, where the type basically functions as an infer var but additionally registering the `impl Trait`'s trait bounds for the infer type. These trait bounds can be used to enforce that predicates hold, and can guide inference (e.g. for closure signature inference):
```rust
let _: impl Fn(&u8) -> &u8 = |x| x;
```
They are implemented as an additional set of bounds that are registered when the type is lowered during typeck, and then these bounds are tied to a given `CanonicalUserTypeAscription` for borrowck. We enforce these `CanonicalUserTypeAscription` bounds during borrowck to make sure that the `impl Trait` types are sensitive to lifetimes:
```rust
trait Static: 'static {}
impl<T> Static for T where T: 'static {}
let local = 1;
let x: impl Static = &local;
//~^ ERROR `local` does not live long enough
```
r? oli-obk
cc #63065
---
Why can't we just use TAIT inference or something? Well, TAITs in bodies have the problem that they cannot reference lifetimes local to a body. For example:
```rust
type TAIT = impl Display;
let local = 0;
let x: TAIT = &local;
//~^ ERROR `local` does not live long enough
```
That's because TAITs requires us to do *opaque type inference* which is pretty strict, since we need to remap all of the lifetimes of the hidden type to universal regions. This is simply not possible here.
---
I consider this part of the "impl trait everywhere" experiment. I'm not certain if this needs yet another lang team experiment.
Rollup of 8 pull requests
Successful merges:
- #134252 (Fix `Path::is_absolute` on Hermit)
- #134254 (Fix building `std` for Hermit after `c_char` change)
- #134255 (Update includes in `/library/core/src/error.rs`.)
- #134261 (Document the symbol Visibility enum)
- #134262 (Arbitrary self types v2: adjust diagnostic.)
- #134265 (Rename `ty_def_id` so people will stop using it by accident)
- #134271 (Arbitrary self types v2: better feature gate test)
- #134274 (Add check-pass test for `&raw`)
r? `@ghost`
`@rustbot` modify labels: rollup
Remove `Lexer`'s dependency on `Parser`.
Lexing precedes parsing, as you'd expect: `Lexer` creates a `TokenStream` and `Parser` then parses that `TokenStream`.
But, in a horrendous violation of layering abstractions and common sense, `Lexer` depends on `Parser`! The `Lexer::unclosed_delim_err` method does some error recovery that relies on creating a `Parser` to do some post-processing of the `TokenStream` that the `Lexer` just created.
This commit just removes `unclosed_delim_err`. This change removes `Lexer`'s dependency on `Parser`, and also means that `lex_token_tree`'s return value can have a more typical form.
The cost is slightly worse error messages in two obscure cases, as shown in these tests:
- tests/ui/parser/brace-in-let-chain.rs: there is slightly less explanation in this case involving an extra `{`.
- tests/ui/parser/diff-markers/unclosed-delims{,-in-macro}.rs: the diff marker detection is no longer supported (because that detection is implemented in the parser).
In my opinion this cost is outweighed by the magnitude of the code cleanup.
r? ```````@chenyukang```````
Try to evaluate constants in legacy mangling
Best reviewed commit by commit.
It seems kind of odd to treat literals differently from unevaluated free constants. So let's evaluate those constants and only fall back to `_` rendering if that fails to result in an integral constant
Add check-pass test for `&raw`
`&raw` denotes a normal/non-raw borrow of the path `raw`, not the start of raw borrow since it's not followed by either `const` or `mut`. Ensure this (and variants) will never regress!
When I saw the open diagnostic issue https://github.com/rust-lang/rust/issues/133231 (better parse error (recovery) on `&raw <expr>`), it made me think that we have to make sure that we will never commit too early/overzealously(†) when encountering the sequence `&raw`, even during parse error recovery!
Modifying the parser to eagerly treat `&raw` as the start of a raw borrow expr only lead to a single UI test failing, namely [tests/ui/enum-discriminant/ptr_niche.rs](4847d6a9d0/tests/ui/enum-discriminant/ptr_niche.rs). However, this is just coincidental — it didn't *intentionally* test this edge case of the grammar.
---
†: With "eager" I mean something like:
```patch
diff --git a/compiler/rustc_parse/src/parser/expr.rs b/compiler/rustc_parse/src/parser/expr.rs
index 0904a42d8a4..68d690fd602 100644
--- a/compiler/rustc_parse/src/parser/expr.rs
+++ b/compiler/rustc_parse/src/parser/expr.rs
`@@` -873,11 +873,16 `@@` fn error_remove_borrow_lifetime(&self, span: Span, lt_span: Span) {
/// Parse `mut?` or `raw [ const | mut ]`.
fn parse_borrow_modifiers(&mut self) -> (ast::BorrowKind, ast::Mutability) {
- if self.check_keyword(kw::Raw) && self.look_ahead(1, Token::is_mutability) {
+ if self.eat_keyword(kw::Raw) {
// `raw [ const | mut ]`.
- let found_raw = self.eat_keyword(kw::Raw);
- assert!(found_raw);
- let mutability = self.parse_const_or_mut().unwrap();
+ let mutability = self.parse_const_or_mut().unwrap_or_else(|| {
+ let span = self.prev_token.span;
+ self.dcx().emit_err(ExpectedMutOrConstInRawBorrowExpr {
+ span,
+ after_ampersand: span.shrink_to_hi(),
+ });
+ ast::Mutability::Not
+ });
(ast::BorrowKind::Raw, mutability)
} else {
// `mut?`
```
---
r? compiler
Arbitrary self types v2: better feature gate test
Slight improvement to the test for the `arbitrary_self_types_pointers` feature gate, to ensure it's independent of the `arbitrary_self_types` gate.
Part of #44874
r? `@wesleywiser`
Arbitrary self types v2: adjust diagnostic.
The recently landed PR #132961 to adjust arbitrary self types was a bit overenthusiastic, advising folks to use the new Receiver trait even before it's been stabilized. Revert to the older wording of the lint in such cases.
Tracking issue #44874
r? ``@wesleywiser``
rustc_borrowck: Stop suggesting the invalid syntax `&mut raw const`
A legitimate suggestion would be to change from
&raw const val
to
&raw mut val
But until we have figured out how to make that happen we should at least
stop suggesting invalid syntax.
I recommend review commit-by-commit.
Part of #127562
Tweak multispan rendering to reduce output length
Consider comments and bare delimiters the same as an "empty line" for purposes of hiding rendered code output of long multispans. This results in more aggressive shortening of rendered output without losing too much context, specially in `*.stderr` tests that have "hidden" comments. We do that check not only on the first 4 lines of the multispan, but now also on the previous to last line as well.
Rollup of 7 pull requests
Successful merges:
- #133900 (Advent of `tests/ui` (misc cleanups and improvements) [1/N])
- #133937 (Keep track of parse errors in `mod`s and don't emit resolve errors for paths involving them)
- #133938 (`rustc_mir_dataflow` cleanups, including some renamings)
- #134058 (interpret: reduce usage of TypingEnv::fully_monomorphized)
- #134130 (Stop using driver queries in the public API)
- #134140 (Add AST support for unsafe binders)
- #134229 (Fix typos in docs on provenance)
r? `@ghost`
`@rustbot` modify labels: rollup
When we recover from a pattern parse error, or a pattern uses `..`, we keep track of that and affect resolution error for missing bindings that could have been provided by that pattern. We differentiate between `..` and parse recovery. We silence resolution errors likely caused by the pattern parse error.
```
error[E0425]: cannot find value `title` in this scope
--> $DIR/struct-pattern-with-missing-fields-resolve-error.rs:19:30
|
LL | println!("[{}]({})", title, url);
| ^^^^^ not found in this scope
|
note: `Website` has a field `title` which could have been included in this pattern, but it wasn't
--> $DIR/struct-pattern-with-missing-fields-resolve-error.rs:17:12
|
LL | / struct Website {
LL | | url: String,
LL | | title: Option<String> ,
| | ----- defined here
LL | | }
| |_-
...
LL | if let Website { url, .. } = website {
| ^^^^^^^^^^^^^^^^^^^ this pattern doesn't include `title`, which is available in `Website`
```
Fix#74863.
forbid toggling x87 and fpregs on hard-float targets
Part of https://github.com/rust-lang/rust/issues/116344, follow-up to https://github.com/rust-lang/rust/pull/129884:
The `x87` target feature on x86 and the `fpregs` target feature on ARM must not be disabled on a hardfloat target, as that would change the float ABI. However, *enabling* `fpregs` on ARM is [explicitly requested](https://github.com/rust-lang/rust/issues/130988) as it seems to be useful. Therefore, we need to refine the distinction of "forbidden" target features and "allowed" target features: all (un)stable target features can determine on a per-target basis whether they should be allowed to be toggled or not. `fpregs` then checks whether the current target has the `soft-float` feature, and if yes, `fpregs` is permitted -- otherwise, it is not. (Same for `x87` on x86).
Also fixes https://github.com/rust-lang/rust/issues/132351. Since `fpregs` and `x87` can be enabled on some builds and disabled on others, it would make sense that one can query it via `cfg`. Therefore, I made them behave in `cfg` like any other unstable target feature.
The first commit prepares the infrastructure, but does not change behavior. The second commit then wires up `fpregs` and `x87` with that new infrastructure.
r? `@workingjubilee`
While normal generics can be skipped in this case, no-names need
something to show here.
Before: `TyCtxt, , Symbol -> bool`
After: `TyCtxt, Into<DefId>, Symbol -> bool`
Slight improvement to the test for the arbitrary_self_types_pointers
feature gate, to ensure it's independent of the arbitrary_self_types
gate.
Part of #44874
Add AST support for unsafe binders
I'm splitting up #130514 into pieces. It's impossible for me to keep up with a huge PR like that. I'll land type system support for this next, probably w/o MIR lowering, which will come later.
r? `@oli-obk`
cc `@BoxyUwU` and `@lcnr` who also may want to look at this, though this PR doesn't do too much yet
Keep track of parse errors in `mod`s and don't emit resolve errors for paths involving them
When we expand a `mod foo;` and parse `foo.rs`, we now track whether that file had an unrecovered parse error that reached the end of the file. If so, we keep that information around in the HIR and mark its `DefId` in the `Resolver`. When resolving a path like `foo::bar`, we do not emit any errors for "`bar` not found in `foo`", as we know that the parse error might have caused `bar` to not be parsed and accounted for.
When this happens in an existing project, every path referencing `foo` would be an irrelevant compile error. Instead, we now skip emitting anything until `foo.rs` is fixed. Tellingly enough, we didn't have any test for errors caused by expansion of `mod`s with parse errors.
Fix https://github.com/rust-lang/rust/issues/97734.
Advent of `tests/ui` (misc cleanups and improvements) [1/N]
Part of #133895.
Misc improvements to some ui tests immediately under `tests/ui/`.
Best reviewed commit-by-commit.
Thanks `@clubby789` for PR title suggestion 😸.
r? compiler
The recently landed PR to adjust arbitrary self types was a bit
overenthusiastic, advising folks to use the new Receiver trait even
before it's been stabilized. Revert to the older wording of the lint in
such cases.
