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Auto merge of #128771 - carbotaniuman:stabilize_unsafe_attr, r=nnethercote

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Stabilize `unsafe_attributes`

# Stabilization report

## Summary

This is a tracking issue for the RFC 3325: unsafe attributes

We are stabilizing `#![feature(unsafe_attributes)]`,  which makes certain attributes considered 'unsafe', meaning that they must be surrounded by an `unsafe(...)`, as in `#[unsafe(no_mangle)]`.

RFC: rust-lang/rfcs#3325
Tracking issue: #123757

## What is stabilized

### Summary of stabilization

Certain attributes will now be designated as unsafe attributes, namely, `no_mangle`, `export_name`, and `link_section` (stable only), and these attributes will need to be called by surrounding them in `unsafe(...)` syntax. On editions prior to 2024, this is simply an edition lint, but it will become a hard error in 2024. This also works in `cfg_attr`, but `unsafe` is not allowed for any other attributes, including proc-macros ones.

```rust
#[unsafe(no_mangle)]
fn a() {}

#[cfg_attr(any(), unsafe(export_name = "c"))]
fn b() {}
```

For a table showing the attributes that were considered to be included in the list to require unsafe, and subsequent reasoning about why each such attribute was or was not included, see [this comment here](https://github.com/rust-lang/rust/pull/124214#issuecomment-2124753464)

## Tests

The relevant tests are in `tests/ui/rust-2024/unsafe-attributes` and `tests/ui/attributes/unsafe`.
This commit is contained in:
bors 2024-08-17 22:48:42 +00:00
commit 37d56daac6
37 changed files with 64 additions and 134 deletions
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13
compiler/rustc_expand/src/config.rs
View file

@ -265,12 +265,7 @@ impl<'a> StripUnconfigured<'a> {
/// is in the original source file. Gives a compiler error if the syntax of
/// the attribute is incorrect.
pub(crate) fn expand_cfg_attr(&self, cfg_attr: &Attribute, recursive: bool) -> Vec<Attribute> {
validate_attr::check_attribute_safety(
self.features.unwrap_or(&Features::default()),
&self.sess.psess,
AttributeSafety::Normal,
&cfg_attr,
);
validate_attr::check_attribute_safety(&self.sess.psess, AttributeSafety::Normal, &cfg_attr);
let Some((cfg_predicate, expanded_attrs)) =
rustc_parse::parse_cfg_attr(cfg_attr, &self.sess.psess)
@ -395,11 +390,7 @@ impl<'a> StripUnconfigured<'a> {
}
};
validate_attr::deny_builtin_meta_unsafety(
self.features.unwrap_or(&Features::default()),
&self.sess.psess,
&meta_item,
);
validate_attr::deny_builtin_meta_unsafety(&self.sess.psess, &meta_item);
(
parse_cfg(&meta_item, self.sess).map_or(true, |meta_item| {

2
compiler/rustc_expand/src/expand.rs
View file

@ -1882,7 +1882,7 @@ impl<'a, 'b> InvocationCollector<'a, 'b> {
let mut span: Option<Span> = None;
while let Some(attr) = attrs.next() {
rustc_ast_passes::feature_gate::check_attribute(attr, self.cx.sess, features);
validate_attr::check_attr(features, &self.cx.sess.psess, attr);
validate_attr::check_attr(&self.cx.sess.psess, attr);
let current_span = if let Some(sp) = span { sp.to(attr.span) } else { attr.span };
span = Some(current_span);