fix def collector for impl trait
fixes#77329
We now consistently make `impl Trait` a hir owner, requiring some special casing for synthetic generic params.
r? `@eddyb`
stop promoting union field accesses in 'const'
Turns out that promotion of union field accesses is the only difference between "promotion in `const`/`static` bodies" and "explicit promotion". So if we can remove this, we have finally achieved what I thought to already be the case -- that the bodies of `const`/`static` initializers behave the same as explicit promotion contexts.
The reason we do not want to promote union field accesses is that they can introduce UB, i.e., they can go wrong. We want to [minimize the ways promoteds can fail to evaluate](https://github.com/rust-lang/const-eval/issues/53). Also this change makes things more consistent overall, removing a special case that was added without much consideration (as far as I can tell).
Cc `@rust-lang/wg-const-eval`
Rollup of 12 pull requests
Successful merges:
- #75115 (`#[deny(unsafe_op_in_unsafe_fn)]` in sys/cloudabi)
- #76614 (change the order of type arguments on ControlFlow)
- #77610 (revise Hermit's mutex interface to support the behaviour of StaticMutex)
- #77830 (Simplify query proc-macros)
- #77930 (Do not ICE with TraitPredicates containing [type error])
- #78069 (Fix const core::panic!(non_literal_str).)
- #78072 (Cleanup constant matching in exhaustiveness checking)
- #78119 (Throw core::panic!("message") as &str instead of String.)
- #78191 (Introduce a temporary for discriminant value in MatchBranchSimplification)
- #78272 (const_evaluatable_checked: deal with unused nodes + div)
- #78318 (TyCtxt: generate single impl block with `slice_interners` macro)
- #78327 (resolve: Relax macro resolution consistency check to account for any errors)
Failed merges:
r? `@ghost`
resolve: Relax macro resolution consistency check to account for any errors
The check was previously omitted only when ambiguity errors or `Res::Err` were encountered, but the "macro-expanded `extern crate` items cannot shadow..." error (at least) can cause same inconsistencies as well.
Fixes https://github.com/rust-lang/rust/issues/78325
Introduce a temporary for discriminant value in MatchBranchSimplification
The optimization introduces additional uses of the discriminant operand, but
does not ensure that it is still valid to evaluate it or that it still
evaluates to the same value.
Evaluate it once at original position, and store the result in a new temporary.
Follow up on #78151. The optimization remains disabled by default.
Closes#78239.
Throw core::panic!("message") as &str instead of String.
This makes `core::panic!("message")` consistent with `std::panic!("message")`, which throws a `&str` and not a `String`.
This also makes any other panics from `core::panicking::panic` result in a `&str` rather than a `String`, which includes compiler-generated panics such as the panics generated for `mem::zeroed()`.
---
Demonstration:
```rust
use std::panic;
use std::any::Any;
fn main() {
panic::set_hook(Box::new(|panic_info| check(panic_info.payload())));
check(&*panic::catch_unwind(|| core::panic!("core")).unwrap_err());
check(&*panic::catch_unwind(|| std::panic!("std")).unwrap_err());
}
fn check(msg: &(dyn Any + Send)) {
if let Some(s) = msg.downcast_ref::<String>() {
println!("Got a String: {:?}", s);
} else if let Some(s) = msg.downcast_ref::<&str>() {
println!("Got a &str: {:?}", s);
}
}
```
Before:
```
Got a String: "core"
Got a String: "core"
Got a &str: "std"
Got a &str: "std"
```
After:
```
Got a &str: "core"
Got a &str: "core"
Got a &str: "std"
Got a &str: "std"
```
Cleanup constant matching in exhaustiveness checking
This supercedes https://github.com/rust-lang/rust/pull/77390. I made the `Opaque` constructor work.
I have opened two issues https://github.com/rust-lang/rust/issues/78071 and https://github.com/rust-lang/rust/issues/78057 from the discussion we had on the previous PR. They are not regressions nor directly related to the current PR so I thought we'd deal with them separately.
I left a FIXME somewhere because I didn't know how to compare string constants for equality. There might even be some unicode things that need to happen there. In the meantime I preserved previous behavior.
EDIT: I accidentally fixed#78071
Fix const core::panic!(non_literal_str).
Invocations of `core::panic!(x)` where `x` is not a string literal expand to `panic!("{}", x)`, which is not understood by the const panic logic right now. This adds `panic_str` as a lang item, and modifies the const eval implementation to hook into this item as well.
This fixes the issue mentioned here: https://github.com/rust-lang/rust/issues/51999#issuecomment-687604248
r? `@RalfJung`
`@rustbot` modify labels: +A-const-eval
Unconditionally capture tokens for attributes.
This allows us to avoid synthesizing tokens in `prepend_attr`, since we
have the original tokens available.
We still need to synthesize tokens when expanding `cfg_attr`,
but this is an unavoidable consequence of the syntax of `cfg_attr` -
the user does not supply the `#` and `[]` tokens that a `cfg_attr`
expands to.
This is based on PR https://github.com/rust-lang/rust/pull/77250 - this PR exposes a bug in the current `collect_tokens` implementation, which is fixed by the rewrite.
Fixes#75982
The direct parent of a module may not be a module
(e.g. `const _: () = { #[path = "foo.rs"] mod foo; };`).
To find the parent of a module for purposes of resolution, we need to
walk up the tree until we hit a module or a crate root.
When the 'early' and 'late' visitors visit an attribute target, they
activate any lint attributes (e.g. `#[allow]`) that apply to it.
This can affect warnings emitted on sibiling attributes. For example,
the following code does not produce an `unused_attributes` for
`#[inline]`, since the sibiling `#[allow(unused_attributes)]` suppressed
the warning.
```rust
trait Foo {
#[allow(unused_attributes)] #[inline] fn first();
#[inline] #[allow(unused_attributes)] fn second();
}
```
However, we do not do this for statements - instead, the lint attributes
only become active when we visit the struct nested inside `StmtKind`
(e.g. `Item`).
Currently, this is difficult to observe due to another issue - the
`HasAttrs` impl for `StmtKind` ignores attributes for `StmtKind::Item`.
As a result, the `unused_doc_comments` lint will never see attributes on
item statements.
This commit makes two interrelated fixes to the handling of inert
(non-proc-macro) attributes on statements:
* The `HasAttr` impl for `StmtKind` now returns attributes for
`StmtKind::Item`, treating it just like every other `StmtKind`
variant. The only place relying on the old behavior was macro
which has been updated to explicitly ignore attributes on item
statements. This allows the `unused_doc_comments` lint to fire for
item statements.
* The `early` and `late` lint visitors now activate lint attributes when
invoking the callback for `Stmt`. This ensures that a lint
attribute (e.g. `#[allow(unused_doc_comments)]`) can be applied to
sibiling attributes on an item statement.
For now, the `unused_doc_comments` lint is explicitly disabled on item
statements, which preserves the current behavior. The exact locatiosn
where this lint should fire are being discussed in PR #78306
improve const infer error
For type inference we probably have to be careful about subtyping and stuff but considering that subtyping shouldn't be relevant for constants I don't really see a reason why we may not want to reuse the const origin here.
r? `@varkor`
passes: `check_attr` on more targets
This PR modifies `check_attr` so that:
- Enum variants are now checked (some attributes would not have been prohibited on variants previously).
- `check_expr_attributes` and `check_stmt_attributes` are removed as `check_attributes` can perform the same checks. This means that codegen attribute errors aren't shown if there are other errors first (e.g. from other attributes, as shown in `src/test/ui/macros/issue-68060.rs` changes below).
Avoid extraneous space between visibility kw and ident for statics
Today, given a static like `static mut FOO: usize = 1`, rustdoc would
emit `static mut FOO: usize = 1`, as it emits both the mutability kw
with a space and reserves a space after the mutability kw. This patch
fixes that misformatting.
This patch also adds some tests for emit of other statics, as I could
not find an existing test devoted to statics.
