Always evaluate free constants and statics, even if previous errors occurred
work towards https://github.com/rust-lang/rust/issues/79738
We will need to evaluate static items before the `definitions.freeze()` below, as we will start creating new `DefId`s (for nested allocations) within the `eval_static_initializer` query.
But even without that motivation, this is a good change. Hard errors should always be reported and not silenced if other errors happened earlier.
return `ty::Error` when equating `ty::Error`
This helps iron out a difference in diagnostics between `Sub` and `Equate` relations, which I'm currently trying to unify.
r? oli-obk
Drive-by `DUMMY_SP` -> `Span` and fmt changes
Noticed these while doing something else. There's no practical change, but it's preferable to use `DUMMY_SP` as little as possible, particularly when we have perfectlly useful `Span`s available.
Merge `CompilerError::CompilationFailed` and `CompilerError::ICE`.
`CompilerError` has `CompilationFailed` and `ICE` variants, which seems reasonable at first. But the way it identifies them is flawed:
- If compilation errors out, i.e. `RunCompiler::run` returns an `Err`, it uses `CompilationFailed`, which is reasonable.
- If compilation panics with `FatalError`, it catches the panic and uses `ICE`. This is sometimes right, because ICEs do cause `FatalError` panics, but sometimes wrong, because certain compiler errors also cause `FatalError` panics. (The compiler/rustdoc/clippy/whatever just catches the `FatalError` with `catch_with_exit_code` in `main`.)
In other words, certain non-ICE compilation failures get miscategorized as ICEs. It's not possible to reliably distinguish the two cases, so this commit merges them. It also renames the combined variant as just `Failed`, to better match the existing `Interrupted` and `Skipped` variants.
Here is an example of a non-ICE failure that causes a `FatalError` panic, from `tests/ui/recursion_limit/issue-105700.rs`:
```
#![recursion_limit="4"]
#![invalid_attribute]
#![invalid_attribute]
#![invalid_attribute]
#![invalid_attribute]
#![invalid_attribute]
//~^ERROR recursion limit reached while expanding
fn main() {{}}
```
r? ``@spastorino``
Change leak check and suspicious auto trait lint warning messages
The leak check lint message "this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!" is misleading as some cases may not be phased out and could end being accepted. This is under discussion still.
The suspicious auto trait lint the change in behavior already happened, so the new message is probably more accurate.
r? `@lcnr`
Closes#93367
deduplicate infer var instantiation
Having 3 separate implementations of one of the most subtle parts of our type system is not a good strategy if we want to maintain a sound type system ✨ while working on this I already found some subtle bugs in the existing code, so that's awesome 🎉 cc #121159
This was necessary as I am not confident in my nll changes in #119106, so I am first cleaning this up in a separate PR.
r? `@BoxyUwU`
Noticed these while doing something else. There's no practical change, but it's preferable to use `DUMMY_SP` as little as possible, particularly when we have perfectlly useful `Span`s available.
macro_rules: Preserve all metavariable spans in a global side table
This PR preserves spans of `tt` metavariables used to pass tokens to declarative macros.
Such metavariable spans can then be used in span combination operations like `Span::to` to improve all kinds of diagnostics.
Spans of non-`tt` metavariables are currently kept in nonterminal tokens, but the long term plan is remove all nonterminal tokens from rustc parser and rely on the proc macro model with invisible delimiters (#114647, #67062).
In particular, `NtIdent` nonterminal (corresponding to `ident` metavariables) becomes easy to remove when this PR lands (#119412 does it).
The metavariable spans are kept in a global side table keyed by `Span`s of original tokens.
The alternative to the side table is keeping them in `SpanData` instead, but the performance regressions would be large because any spans from tokens passed to declarative macros would stop being inline and would work through span interner instead, and the penalty would be paid even if we never use the metavar span for the given original span.
(But also see the comment on `fn maybe_use_metavar_location` describing the map collision issues with the side table approach.)
There are also other alternatives - keeping the metavar span in `Token` or `TokenTree`, but associating it with `Span` itsel is the most natural choice because metavar spans are used in span combining operations, and those operations are not necessarily tied to tokens.
Add help to `hir_analysis_unrecognized_intrinsic_function`
To help remind forgetful people like me what step they forgot.
(If this just ICE'd, https://github.com/rust-lang/compiler-team/issues/620 style, the stack trace would point me here, but since there's a "nice" error that information is lost.)
Tracking import use types for more accurate redundant import checking
fixes#117448
By tracking import use types to check whether it is scope uses or the other situations like module-relative uses, we can do more accurate redundant import checking.
For example unnecessary imports in std::prelude that can be eliminated:
```rust
use std::option::Option::Some;//~ WARNING the item `Some` is imported redundantly
use std::option::Option::None; //~ WARNING the item `None` is imported redundantly
```
fixes#117448
For example unnecessary imports in std::prelude that can be eliminated:
```rust
use std::option::Option::Some;//~ WARNING the item `Some` is imported redundantly
use std::option::Option::None; //~ WARNING the item `None` is imported redundantly
```
Rollup of 7 pull requests
Successful merges:
- #120526 (rustdoc: Correctly handle long crate names on mobile)
- #121100 (Detect when method call on argument could be removed to fulfill failed trait bound)
- #121160 (rustdoc: fix and refactor HTML rendering a bit)
- #121198 (Add more checks for `unnamed_fields` during HIR analysis)
- #121218 (Fix missing trait impls for type in rustc docs)
- #121221 (AstConv: Refactor lowering of associated item bindings a bit)
- #121237 (Use better heuristic for printing Cargo specific diagnostics)
r? `@ghost`
`@rustbot` modify labels: rollup
Add more checks for `unnamed_fields` during HIR analysis
Fixes#121151
I also found that we don't prevent enums here so
```rs
#[repr(C)]
#[derive(Debug)]
enum A {
#[default]
B,
C,
}
#[repr(C)]
#[derive(Debug)]
struct D {
_: A,
}
```
leads to an ICE on an `self.is_struct() || self.is_union()` assertion, so fixed that too.
rustdoc: fix and refactor HTML rendering a bit
* refactoring: get rid of a bunch of manual `f.alternate()` branches
* not sure why this wasn't done so already, is this perf-sensitive?
* fix an ICE in debug builds of rustdoc
* rustdoc used to crash on empty outlives-bounds: `where 'a:`
* properly escape const generic defaults
* actually print empty trait and outlives-bounds (doesn't work for cross-crate reexports yet, will fix that at some other point) since they can have semantic significance
* outlives-bounds: forces lifetime params to be early-bound instead of late-bound which is technically speaking part of the public API
* trait-bounds: can affect the well-formedness, consider
* makeshift “const-evaluatable” bounds under `generic_const_exprs`
* bounds to force wf-checking in light of #100041 (quite artificial I know, I couldn't figure out something better), see https://github.com/rust-lang/rust/pull/121160#discussion_r1491563816
Properly deal with weak alias types as self types of impls
Fixes#114216.
Fixes#116100.
Not super happy about the two ad hoc “normalization” implementations for weak alias types:
1. In `inherent_impls`: The “peeling”, normalization to [“WHNF”][whnf]: Semantically that's exactly what we want (neither proper normalization nor shallow normalization would be correct here). Basically a weak alias type is “nominal” (well...^^) if the WHNF is nominal. [#97974](https://github.com/rust-lang/rust/pull/97974) followed the same approach.
2. In `constrained_generic_params`: Generic parameters are constrained by a weak alias type if the corresp. “normalized” type constrains them (where we only normalize *weak* alias types not arbitrary ones). Weak alias types are injective if the corresp. “normalized” type is injective.
Both have ad hoc overflow detection mechanisms.
**Coherence** is handled in #117164.
r? `@oli-obk` or types
[whnf]: https://en.wikipedia.org/wiki/Lambda_calculus_definition#Weak_head_normal_form
Use fulfillment in next trait solver coherence
Use fulfillment in the new trait solver's `impl_intersection_has_impossible_obligation` routine. This means that inference that falls out of processing other obligations can influence whether we can determine if an obligation is impossible to satisfy. See the committed test.
This should be completely sound, since evaluation and fulfillment both respect intercrate mode equally.
We run the risk of breaking coherence later if we were to change the rules of fulfillment and/or inference during coherence, but this is a problem which affects evaluation, as nested obligations from a trait goal are processed together and can influence each other in the same way.
r? lcnr
cc #114862
Also changed obligationctxt -> fulfillmentctxt because it feels kind of redundant to use an ocx here. I don't really care enough and can change it back if it really matters much.
errors: only eagerly translate subdiagnostics
Subdiagnostics don't need to be lazily translated, they can always be eagerly translated. Eager translation is slightly more complex as we need to have a `DiagCtxt` available to perform the translation, which involves slightly more threading of that context.
This slight increase in complexity should enable later simplifications - like passing `DiagCtxt` into `AddToDiagnostic` and moving Fluent messages into the diagnostic structs rather than having them in separate files (working on that was what led to this change).
r? ```@nnethercote```
Don't use mem::zeroed in vec::IntoIter
`mem::zeroed` is not a trivial function. Maybe it was once, but now it involves multiple locals, copies, and an intrinsic that gets monomorphized into a call to `panic_nounwind` for iterators of types like `Vec<&T>`. Of course all that complexity is trivially optimized out, but generating a bunch of IR where we don't need to just so we can optimize it away later is silly.
coverage: Discard spans that fill the entire function body
While debugging some other coverage changes, I discovered a frustrating inconsistency that occurs in functions containing closures, if they end with an implicit `()` return instead of an explicit trailing-expression.
This turns out to have been caused by the corresponding node in MIR having a span that covers the entire function body. When preparing coverage spans, any span that fills the whole body tends to cause more harm than good, so this PR detects and discards those spans.
(This isn't the first time whole-body spans have caused problems; we also eliminated some of them in #118525.)
const_mut_refs: allow mutable pointers to statics
Fixes https://github.com/rust-lang/rust/issues/118447
Writing this PR became a bit messy, see [Zulip](https://rust-lang.zulipchat.com/#narrow/stream/146212-t-compiler.2Fconst-eval/topic/Statics.20pointing.20to.20interior.20mutable.20statics) for some of my journey.^^ Turns out there was a long-standing bug in our qualif logic that led to us incorrectly classifying certain places as "no interior mut" when they actually had interior mut. Due to that the `const_refs_to_cell` feature gate was required far less often than it otherwise would, e.g. in [this code](https://play.rust-lang.org/?version=nightly&mode=debug&edition=2021&gist=9e0c042c451b3d11d64dd6263679a164). Fixing this however would be a massive breaking change all over libcore and likely the wider ecosystem. So I also changed the const-checking logic to just not require the feature gate for the affected cases. While doing so I discovered a bunch of logic that is not explained and that I could not explain. However I think stabilizing some const-eval feature will make most of that logic inconsequential so I just added some FIXMEs and left it at that.
r? `@oli-obk`
