Emit a warning if the doctest `main` function will not be run
Fixes#140310.
I think we could try to go much further like adding a "link" (ie UI annotations) on the `main` function in the doctest. However that will require some more computation, not sure if it's worth it or not. Can still be done in a follow-up if we want it.
For now, this PR does two things:
1. Pass the `DiagCtxt` to the doctest parser to emit the warning.
2. Correctly generate the `Span` to where the doctest is starting (I hope the way I did it isn't too bad either...).
cc `@fmease`
r? `@notriddle`
rustdoc-json: Remove false docs and add test for inline attribute
The docs about how `#[inline]` was represented isn't true. Updates the comment, and adds a test.
CC #137645
r? `@GuillaumeGomez`
dont handle bool transmute
removes `transmute(u8) -> bool` suggestion due to ambiguity, leave it for clippy
elaboration on ambiguity in question:
`transmute::<u8, bool>(x)` will codegen to an `assume(u8 < 2)`;
`_ == 1` or `_ != 0` or `_ % 2 == 0` would remove that assumption
`match _ { x @ (0 | 1) => x == 1, _ => std::hint::unreachable_unchecked() }` is very verbose
`@rustbot` label L-unnecessary_transmutes
lower bodies' params to thir before the body's value
Two motivations for this:
- Lowering params first means errors from lowering the params are emitted before errors from lowering the body's expression. This comes up in [tests/ui/associated-consts/associated-const-type-parameter-pattern.stderr](https://github.com/rust-lang/rust/compare/master...dianne:rust:thir-lower-params-before-body-expr?expand=1#diff-acac6ea10e991af0da91633e08b2739f9f9ca0c8f826401b6ba829914d0806f2), where both the params and expression encounter errors in translating consts to patterns. This change puts the errors in the order they appear in the source file.
- Guard patterns (#129967) contain expressions, so lowering params containing guard patterns may add more expressions to the THIR. However, there's a check for `-Zunpretty=thir-tree` that the final expression in the THIR corresponds to its value [(link)](c43786c9b7/compiler/rustc_mir_build/src/builder/mod.rs (L453-L455)); lowering params last would break this. As an alternative way to get guard patterns to work, I think the pretty-printer could use the expression returned by `thir_body` and the check could be removed or changed (#141357).
incorrectly prefer builtin `dyn` impls :3
This makes #57893 slightly more exploitable with the new solver. It's still strictly better than the old solver and the underlying unsoundness persists in the new one even without this preference.
Properly fixing #57893 is something we've been looking at more deeply recently and discussed at the [Types Meetup during the All-Hands](https://hackmd.io/rz-4ghMzTb2wXOkdLKHaHw#Dyn-traits). Whatever approach we'll end up deciding on will likely require a fairly long transition period and some significant further design work. This should not block `-Znext-solver`.
fixes https://github.com/rust-lang/trait-system-refactor-initiative/issues/183
r? `@compiler-errors` cc `@rust-lang/types`
limit impls of `VaArgSafe` to just types that are actually safe
tracking issue: https://github.com/rust-lang/rust/issues/44930
Retrieving 8- or 16-bit integer arguments from a `VaList` is not safe, because such types are subject to upcasting. See https://github.com/rust-lang/rust/issues/61275#issuecomment-2193942535 for more detail.
This PR also makes the instances of `VaArgSafe` visible in the documentation, and uses a private sealed trait to make sure users cannot create additional impls of `VaArgSafe`, which would almost certainly cause UB.
r? `@workingjubilee`
Do not eagerly fold consts in `normalize_param_env_or_error` if new solver
Fixes https://github.com/rust-lang/trait-system-refactor-initiative/issues/213
Given:
```
trait Trait: Deref<Target = [u8; { 1 + 1 }]> {}
```
when elaborating param env for `Trait`, we have `Self: Trait`, `Self: Deref<Target = [u8; {anon const}]>`.
Before this PR, we would fold the anon consts away *before* elaborating. However, we end up getting another *un-folded* copy of the anon const from elaborating `Self: Trait`. This leads to normalization ambiguity.
r? lcnr
only resolve top-level guard patterns' guards once
We resolve guard patterns' guards in `resolve_pattern_inner`, so to avoid resolving them multiple times, we must avoid doing so earlier. To accomplish this, `LateResolutionVisitor::visit_pat` contains a case for guard patterns that avoids visiting their guards while walking patterns.
This PR fixes#141265, which was due to `visit::walk_pat` being used instead; this meant guards at the top level of a pattern would be visited twice. e.g. it would ICE on `for x if x in [] {}`, but not `for (x if x) in [] {}`. `visit_pat` was already used for the guard pattern in the second example, on account of the top-level pattern being parens.
8 and 16-bit integers are subject to upcasting in C, and hence are not reliably safe. users should perform their own casting and deal with the consequences
typeck: catch `continue`s pointing to blocks
This taints the typeck results with errors if a `continue` is found not pointing to a loop.
A few things were going wrong here. First, since this wasn't caught in typeck, we'd end up building the THIR and then running liveness lints on ill-formed HIR. Since liveness assumes all `continue`s point to loops, it wasn't setting a live node for the `continue`'s destination. There was a fallback for if it couldn't retrieve that live node, but it was faulty; it would create a new live node to represent an erroneous state after the analysis's RWU table had already been built. This would ICE if the new live node was used in operations, such as merging results from the arms of a match. I've removed this error-recovery since it was buggy, and we should really catch bad labels before liveness.
I've also replaced an outdated comment about when liveness lints are run. At this point, I think the call to `check_liveness` could be moved elsewhere, but if it can be run when the typeck results are tainted by errors, it'll need some slight refactoring so it can bail out in that case. In lieu of that, I've added an assert.
Fixes#113379Fixes#121623
Suggest use "{}", self.x instead of {self.x} when resolve x as field of `self`
Fixes#141136
Changes can be seen in the second commit: 9de7fff0d8
r? compiler
Add match guard let chain drop order and scoping tests
We have a bunch of tests for if let chain drop order, but those tests don't cover match guard chains to the same depth. This PR adds the following tests:
* match guard equivalents of the if let chains tests in the `drop-order-comparisons.rs` test, added by #133605.
* match guard equivalent of the `mir_let_chains_drop_order.rs` test, added by #107251
* match guard equivalent of `temporary-early-drop.rs`, added by #133093
The added tests all have variants for 2021 and 2024, showing that the behavior on both editions matches that of if let chains on 2024.
tracking issue: https://github.com/rust-lang/rust/issues/51114
collect doc alias as tips during resolution
Close#124273
Collect the symbol in the doc alias attributes and provide a tip when a match is found.
r? `@estebank`
This taints the typeck results with errors if a `continue` is found not
pointing to a loop, which fixes an ICE.
A few things were going wrong here. First, since this wasn't caught in
typeck, we'd end up building the THIR and then running liveness lints on
ill-formed HIR. Since liveness assumes all `continue`s point to loops,
it wasn't setting a live node for the `continue`'s destination. However,
the fallback for this was faulty; it would create a new live node to
represent the erroneous state after the analysis's RWU table had already
been built. This would ICE if the new live node was used in operations,
such as merging results from the arms of a match. I've removed this
error-recovery since it was buggy, and we should really catch bad labels
before liveness.
I've also replaced an outdated comment about when liveness lints are
run. At this point, I think the call to `check_liveness` could be moved
elsewhere, but if it can be run when the typeck results are tainted by
errors, it'll need some slight refactoring so it can bail out in that
case. In lieu of that, I've added an assertion.
`gather_locals`: only visit guard pattern guards when checking the guard
When checking a pattern with guards in it, `GatherLocalsVisitor` will visit both the pattern (when type-checking the let, arm, or param containing it) and local declarations in the guard expression (when checking the guard itself). This keeps it from visiting the guard when visiting the pattern, since otherwise it would gather locals from the guard twice, which would lead to a delayed bug: "evaluated expression more than once".
Tracking issue for guard patterns: #129967
Warning added when dependency crate has async drop types, and the feature is disabled
In continue of https://github.com/rust-lang/rust/pull/141031.
When dependency crate has non-empty `adt_async_destructor` table in metadata, and `async_drop` feature is disabled for local crate, warning will be emitted.
Test `dependency-dropped` has two revisions - with and without feature enabled. With feature enabled, async drop for dropee is executed ("Async drop" printed). Without the feature enabled, sync drop is executed ("Sync drop" printed) and warning is emitted.
Warning example:
```
warning: found async drop types in dependecy `async_drop_dep`, but async_drop feature is disabled for `dependency_dropped`
--> $DIR/dependency-dropped.rs:7:1
|
LL | #![cfg_attr(with_feature, feature(async_drop))]
| ^
|
= help: if async drop type will be dropped in a crate without `feature(async_drop)`, sync Drop will be used
```
Resolved issue with mismatched types triggering ICE in certain scenarios
## Background
The function `annotate_mut_binding_to_immutable_binding` called in `emit_coerce_suggestions` performs a type comparison between the `expected` and `found` types from `ExpectedFound` in the `TypeError`. This can fail if the `found` type contains a region variable that's been rolled back.
## What is being changed?
This updates `annotate_mut_binding_to_immutable_binding` to use `expr_ty` and `expected` from the parent function instead of the types from the `TypeError`. This sidesteps the issue of using `found` from `TypeError` which may leak lingering inference region variables.
This does change the diagnostic behavior to _only_ support cases where the expected outermost type is `&T`, but that seems to be the intended functionality.
Also fixed the example in the `annotate_mut_binding_to_immutable_binding` rustdocs.
r? rust-lang/types
Fixes#140823
