
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`.
UI Tests
This folder contains rustc
's
UI tests.
Test Directives (Headers)
Typically, a UI test will have some test directives / headers which are special comments that tell compiletest how to build and intepret a test.
As part of an on-going effort to rewrite compiletest
(see https://github.com/rust-lang/compiler-team/issues/536), a major
change proposal to change legacy compiletest-style headers // <directive>
to ui_test
-style headers
//@ <directive>
was accepted (see
https://github.com/rust-lang/compiler-team/issues/512.
An example directive is ignore-test
. In legacy compiletest style, the header
would be written as
// ignore-test
but in ui_test
style, the header would be written as
//@ ignore-test
compiletest is changed to accept only //@
directives for UI tests
(currently), and will reject and report an error if it encounters any
comments // <content>
that may be parsed as an legacy compiletest-style
test header. To fix this, you should migrate to the ui_test
-style header
//@ <content>
.