improve tool-only help for multiple `#[default]` variants
When defining an enum with multiple `#[default]` variants, we emit a tool-only suggestion for every `#[default]`ed variant to remove all other `#[default]`s. This PR improves the suggestion to correctly handle the cases where one variant has multiple `#[default]`s and where different `#[default]`s have the same span due to macro expansions.
fixes https://github.com/rust-lang/rust/issues/118119
Rollup of 6 pull requests
Successful merges:
- #118012 (Add support for global allocation in smir)
- #118013 (Enable Rust to use the EHCont security feature of Windows)
- #118100 (Enable profiler in dist-powerpc64-linux)
- #118142 (Tighten up link attributes for llvm-wrapper bindings)
- #118147 (Fix some unnecessary casts)
- #118161 (Allow defining opaques in `check_coroutine_obligations`)
r? `@ghost`
`@rustbot` modify labels: rollup
Allow defining opaques in `check_coroutine_obligations`
In the new trait solver, when an obligation stalls on an unresolved coroutine witness, we will stash away the *root* obligation, even if the stalled obligation is only a distant descendent of the root obligation, since the new solver is purely recursive.
This means that we may need to reprocess alias-relate obligations (and others) which may define opaque types in the new solver. Currently, we use the coroutine's def id as the defining anchor in `check_coroutine_obligations`, which will allow defining no opaque types, resulting in errors like:
```
error[E0271]: type mismatch resolving `{coroutine@<source>:6:5: 6:17} <: impl Clone`
--> <source>:6:5
|
6 | / move |_: ()| {
7 | | let () = yield ();
8 | | }
| |_____^ types differ
```
So this PR fixes the defining anchor and does the same trick as `check_opaque_well_formed`, where we manually compare opaques that were defined against their hidden types to make sure they weren't defined differently when processing these stalled coroutine obligations.
r? `@lcnr` cc `@cjgillot`
Add allow-by-default lint for unit bindings
### Example
```rust
#![warn(unit_bindings)]
macro_rules! owo {
() => {
let whats_this = ();
}
}
fn main() {
// No warning if user explicitly wrote `()` on either side.
let expr = ();
let () = expr;
let _ = ();
let _ = expr; //~ WARN binding has unit type
let pat = expr; //~ WARN binding has unit type
let _pat = expr; //~ WARN binding has unit type
// No warning for let bindings with unit type in macro expansions.
owo!();
// No warning if user explicitly annotates the unit type on the binding.
let pat: () = expr;
}
```
outputs
```
warning: binding has unit type `()`
--> $DIR/unit-bindings.rs:17:5
|
LL | let _ = expr;
| ^^^^-^^^^^^^^
| |
| this pattern is inferred to be the unit type `()`
|
note: the lint level is defined here
--> $DIR/unit-bindings.rs:3:9
|
LL | #![warn(unit_bindings)]
| ^^^^^^^^^^^^^
warning: binding has unit type `()`
--> $DIR/unit-bindings.rs:18:5
|
LL | let pat = expr;
| ^^^^---^^^^^^^^
| |
| this pattern is inferred to be the unit type `()`
warning: binding has unit type `()`
--> $DIR/unit-bindings.rs:19:5
|
LL | let _pat = expr;
| ^^^^----^^^^^^^^
| |
| this pattern is inferred to be the unit type `()`
warning: 3 warnings emitted
```
This lint is not triggered if any of the following conditions are met:
- The user explicitly annotates the binding with the `()` type.
- The binding is from a macro expansion.
- The user explicitly wrote `let () = init;`
- The user explicitly wrote `let pat = ();`. This is allowed for local lifetimes.
### Known Issue
It is known that this lint can trigger on some proc-macro generated code whose span returns false for `Span::from_expansion` because e.g. the proc-macro simply forwards user code spans, and otherwise don't have distinguishing syntax context compared to non-macro-generated code. For those kind of proc-macros, I believe the correct way to fix them is to instead emit identifers with span like `Span::mixed_site().located_at(user_span)`.
Closes#71432.
Remove `feature` from the list of well known check-cfg name
This PR removes `feature` from the list of well known check-cfg.
This is done for multiple reasons:
- Cargo is the source of truth, rustc shouldn't have any knowledge of it
- It creates a conflict between Cargo and rustc when there are no features defined.
In this case Cargo won't pass any `--check-cfg` for `feature` since no feature will ever be passed, but rustc by having in it's list adds a implicit `cfg(feature, values(any()))` which is completely wrong. Having any cfg `feature` is unexpected not allow any `feature` value.
While doing this, I took the opportunity to specialise the diagnostic a bit for the case above.
r? `@petrochenkov`
Don't ICE when ambiguity is found when selecting `Index` implementation in typeck
Fixes#118111
The problem here is when we're manually "selecting" an impl for `base_ty: Index<?0>`, we don't consider placeholder region errors (leak check) or ambiguous predicates. Those can lead to us not actually emitting any fulfillment errors on line 3131.
Fix early param lifetimes in generic_const_exprs
In cases like below, we never actually be able to capture region name for two reasons, first `'static` becomes anonymous lifetime and second we never capture region if it doesn't have a name so this results in ICE.
```
struct DataWrapper<'static> {
data: &'a [u8; Self::SIZE],
}
impl DataWrapper<'a> {
```
Fixes https://github.com/rust-lang/rust/issues/118021
Remove `--check-cfg` checking of command line `--cfg` args
Back in https://github.com/rust-lang/rust/pull/100574 we added to the `unexpected_cfgs` lint the checking of `--cfg` CLI arguments and emitted unexpected names and values for them.
The implementation works as expected, but it's usability in particular when using it in combination with Cargo+`RUSTFLAGS` as people who set `RUSTFLAGS=--cfg=tokio_unstable` (or whatever) have `unexpected_cfgs` warnings on all of their crates is debatable. ~~To fix this issue this PR proposes that we split the CLI argument checking into it's own separate allow-by-default lint: `unexpected_cli_cfgs`.~~
~~This has the advantage of letting people who want CLI warnings have them (although not by default anymore), while still linting on every unexpected cfg name and values in the code.~~
After some discussion with the Cargo team ([Zulip thread](https://rust-lang.zulipchat.com/#narrow/stream/246057-t-cargo/topic/check-cfg.20and.20RUSTFLAGS.20interaction)) and member of the compiler team (see below), I propose that we follow the suggestion from `@epage:` never check `--cfg` arguments, but still reserve us the possibility to do it later.
We would still lint on unexpected cfgs found in the source code no matter the `--cfg` args passed. This mean reverting https://github.com/rust-lang/rust/pull/100574 but NOT https://github.com/rust-lang/rust/pull/99519.
r? `@petrochenkov`
Add `$message_type` field to distinguish json diagnostic outputs
Currently the json-formatted outputs have no way to unambiguously determine which kind of message is being output. A consumer can look for specific fields in the json object (eg "message"), but there's no guarantee that in future some other kind of output will have a field of the same name.
This PR adds a `"type"` field to add json outputs which can be used to unambiguously determine which kind of output it is. The mapping is:
`diagnostic`: regular compiler diagnostics
`artifact`: artifact notifications
`future_incompat`: Future incompatibility report
`unused_extern`: Unused crate warnings/errors
This matches the "internally tagged" representation for serde enums.
Don't consider regions in `deref_into_dyn_supertrait` lint
I actually wonder if we should just warn on *any* deref impl with a target type that matches a supertrait by *def-id*.
cc #89460
r? types
Typeck break expr even if break is illegal
Fixes#117821
We were returning immediately when encountering an illegal break. However, this caused problems later when the expr that the break was returning was evaluated during writeback. So now we don't return and instead simply set tainted by error. This lets typeck of break expr to occur even though we've encountered an illegal break.
Don't require intercrate mode for negative coherence
Negative coherence needs to be *sound*, but does not need to be *complete*, since it's looking for the *existence* of a negative goal, not the non-existence of a positive goal.
This removes some trivial and annoying ambiguities when a negative impl has region constraints.
r? lcnr idk if this needs an fcp but if it does, pls kick it off
Note about object lifetime defaults in does not live long enough error
This is a aspect of Rust that frequently trips up people who are not aware of it yet. This diagnostic attempts to explain what's happening and why the lifetime constraint, that was never mentioned in the source, arose.
The implementation feels a bit questionable, I'm not sure whether there are better ways to do this. There probably are.
fixes#117835
r? types
Add a test to ensure issue #89699 does not show up again. This test
emits an `async move` closure in a proc macro, which is used in a
test program compiled with edition 2015. We make sure the error message
is nice and shows up properly.
We were earlier returning immediately when encountering an illegal break. However, this caused problems later
when the expr that the break was returning was evaluated during writeback. So now we don't return and instead
simply set tainted by error. This lets typeck of break expr to occur even though we've encountered an illegal break.
This lint is not triggered if any of the following conditions are met:
- The user explicitly annotates the binding with the `()` type.
- The binding is from a macro expansion.
- The user explicitly wrote `let () = init;`
- The user explicitly wrote `let pat = ();`. This is allowed for local
lifetimes.
Make regionck care about placeholders in outlives components
Currently, we don't consider a placeholder type `!T` to be a type component when it comes to processing type-outlives obligations. This means that they are essentially treated like unit values with no sub-components, and always outlive any region. This is problematic for `non_lifetime_binders`, and even more problematic for `with_negative_coherence`, since negative coherence uses placeholders as universals.
This PR adds `Component::Placeholder` which acts much like `Component::Param`. This currently causes a regression in some non-lifetime-binders tests because `for<T> T: 'static` doesn't imply itself when processing outlives obligations, so code like this will fail:
```
fn foo() where for<T> T: 'static {
foo() //~ fails
}
```
Since the where clause doesn't imply itself. This requires making the `MatchAgainstHigherRankedOutlives` relation smarter when it comes to binders.
r? types
Ignore but do not assume region obligations from unifying headers in negative coherence
Partly addresses a FIXME that was added in #112875. Just as we can throw away the nested trait/projection obligations from unifying two impl headers, we can also just throw away the region obligations too.
I removed part of the FIXME that was incorrect, namely:
> Given that the only region constraints we get are involving inference regions in the root, it shouldn't matter, but still sus.
This is not true when unifying `fn(A)` and `for<'b> fn(&'b B)` which ends up with placeholder region outlives from non-root universes. I'm pretty sure this is okay, though it would be nice if we were to use them as assumptions. See the `explicit` revision of the test I committed, which still fails.
Fixes#117986
r? lcnr, feel free to reassign tho.
Recover `dyn` and `impl` after `for<...>`
Recover `dyn` and `impl` after `for<...>` in types. Reuses the logic for parsing bare trait objects, so it doesn't fix cases like `for<'a> dyn Trait + dyn Trait` or anything, but that seems somewhat of a different issue.
Parsing recovery logic is a bit involved, but I couldn't find a way to simplify it.
Fixes#117882
interpret: simplify handling of shifts by no longer trying to handle signed and unsigned shift amounts in the same branch
While we're at it, also update comments in codegen and MIR building related to shifts, and fix the overflow error printed by Miri on negative shift amounts.
When encountering struct fn call literal with private fields, suggest all builders
When encountering code like `Box(42)`, suggest `Box::new(42)` and *all* other associated functions that return `-> Box<T>`.
Add a way to give pre-sorted suggestions.
Ensure sanity of all computed ABIs
This moves the ABI sanity assertions from the codegen backend to the ABI computation logic. Sadly, due to past mistakes, we [have to](https://github.com/rust-lang/rust/pull/117351#issuecomment-1788495503) be able to compute a sane ABI for nonsensical function types like `extern "C" fn(str) -> str`. So to make the sanity check pass we first need to make all ABI adjustment deal with unsized types... and we have no shared infrastructure for those adjustments, so that's a bunch of copy-paste. At least we have assertions failing loudly when one accidentally sets a different mode for an unsized argument.
To achieve this, this re-lands the parts of https://github.com/rust-lang/rust/pull/80594 that got reverted in https://github.com/rust-lang/rust/pull/81388. To avoid breaking wasm ABI again, that ABI now explicitly opts-in to the (wrong, broken) ABI that we currently keep for backwards compatibility. That's still better than having *every* ABI use the wrong broken default!
Cc `@bjorn3`
Fixes https://github.com/rust-lang/rust/issues/115845
