bjoernager/rust
bjoernager/rust
1
Fork 0
Code Activity

error on unsafe attributes in pre-2024 editions

Browse source 
the `no_mangle`, `link_section` and `export_name` attributes are exceptions, and can still be used without an unsafe in earlier editions
This commit is contained in:
Folkert de Vries 2025-04-12 19:58:19 +02:00
parent 81d8c747fb
commit f472cc8cd4
No known key found for this signature in database
GPG key ID: 1F17F6FFD112B97C
17 changed files with 102 additions and 52 deletions
Download patch file Download diff file Expand all files Collapse all files

4
compiler/rustc_error_codes/src/error_codes/E0755.md
View file

@ -5,7 +5,7 @@ Erroneous code example:
```compile_fail,E0755
#![feature(ffi_pure)]
#[ffi_pure] // error!
#[unsafe(ffi_pure)] // error!
pub fn foo() {}
# fn main() {}
```
@ -17,7 +17,7 @@ side effects or infinite loops:
#![feature(ffi_pure)]
extern "C" {
#[ffi_pure] // ok!
#[unsafe(ffi_pure)] // ok!
pub fn strlen(s: *const i8) -> isize;
}
# fn main() {}

4
compiler/rustc_error_codes/src/error_codes/E0756.md
View file

@ -6,7 +6,7 @@ Erroneous code example:
```compile_fail,E0756
#![feature(ffi_const)]
#[ffi_const] // error!
#[unsafe(ffi_const)] // error!
pub fn foo() {}
# fn main() {}
```
@ -18,7 +18,7 @@ which have no side effects except for their return value:
#![feature(ffi_const)]
extern "C" {
#[ffi_const] // ok!
#[unsafe(ffi_const)] // ok!
pub fn strlen(s: *const i8) -> i32;
}
# fn main() {}

7
compiler/rustc_error_codes/src/error_codes/E0757.md
View file

@ -6,8 +6,9 @@ Erroneous code example:
#![feature(ffi_const, ffi_pure)]
extern "C" {
#[ffi_const]
#[ffi_pure] // error: `#[ffi_const]` function cannot be `#[ffi_pure]`
#[unsafe(ffi_const)]
#[unsafe(ffi_pure)]
//~^ ERROR `#[ffi_const]` function cannot be `#[ffi_pure]`
pub fn square(num: i32) -> i32;
}
```
@ -19,7 +20,7 @@ As `ffi_const` provides stronger guarantees than `ffi_pure`, remove the
#![feature(ffi_const)]
extern "C" {
#[ffi_const]
#[unsafe(ffi_const)]
pub fn square(num: i32) -> i32;
}
```

33
compiler/rustc_feature/src/builtin_attrs.rs
View file

@ -6,6 +6,7 @@ use AttributeDuplicates::*;
use AttributeGate::*;
use AttributeType::*;
use rustc_data_structures::fx::FxHashMap;
use rustc_span::edition::Edition;
use rustc_span::{Symbol, sym};
use crate::{Features, Stability};
@ -65,9 +66,12 @@ pub enum AttributeSafety {
/// Normal attribute that does not need `#[unsafe(...)]`
Normal,
/// Unsafe attribute that requires safety obligations
/// to be discharged
Unsafe,
/// Unsafe attribute that requires safety obligations to be discharged.
///
/// An error is emitted when `#[unsafe(...)]` is omitted, except when the attribute's edition
/// is less than the one stored in `unsafe_since`. This handles attributes that were safe in
/// earlier editions, but become unsafe in later ones.
Unsafe { unsafe_since: Option<Edition> },
}
#[derive(Clone, Copy)]
@ -187,12 +191,23 @@ macro_rules! template {
}
macro_rules! ungated {
(unsafe($edition:ident) $attr:ident, $typ:expr, $tpl:expr, $duplicates:expr, $encode_cross_crate:expr $(,)?) => {
BuiltinAttribute {
name: sym::$attr,
encode_cross_crate: $encode_cross_crate,
type_: $typ,
safety: AttributeSafety::Unsafe { unsafe_since: Some(Edition::$edition) },
template: $tpl,
gate: Ungated,
duplicates: $duplicates,
}
};
(unsafe $attr:ident, $typ:expr, $tpl:expr, $duplicates:expr, $encode_cross_crate:expr $(,)?) => {
BuiltinAttribute {
name: sym::$attr,
encode_cross_crate: $encode_cross_crate,
type_: $typ,
safety: AttributeSafety::Unsafe,
safety: AttributeSafety::Unsafe { unsafe_since: None },
template: $tpl,
gate: Ungated,
duplicates: $duplicates,
@ -217,7 +232,7 @@ macro_rules! gated {
name: sym::$attr,
encode_cross_crate: $encode_cross_crate,
type_: $typ,
safety: AttributeSafety::Unsafe,
safety: AttributeSafety::Unsafe { unsafe_since: None },
template: $tpl,
duplicates: $duplicates,
gate: Gated(Stability::Unstable, sym::$gate, $msg, Features::$gate),
@ -228,7 +243,7 @@ macro_rules! gated {
name: sym::$attr,
encode_cross_crate: $encode_cross_crate,
type_: $typ,
safety: AttributeSafety::Unsafe,
safety: AttributeSafety::Unsafe { unsafe_since: None },
template: $tpl,
duplicates: $duplicates,
gate: Gated(Stability::Unstable, sym::$attr, $msg, Features::$attr),
@ -423,9 +438,9 @@ pub static BUILTIN_ATTRIBUTES: &[BuiltinAttribute] = &[
),
ungated!(no_link, Normal, template!(Word), WarnFollowing, EncodeCrossCrate::No),
ungated!(repr, Normal, template!(List: "C"), DuplicatesOk, EncodeCrossCrate::No),
ungated!(unsafe export_name, Normal, template!(NameValueStr: "name"), FutureWarnPreceding, EncodeCrossCrate::No),
ungated!(unsafe link_section, Normal, template!(NameValueStr: "name"), FutureWarnPreceding, EncodeCrossCrate::No),
ungated!(unsafe no_mangle, Normal, template!(Word), WarnFollowing, EncodeCrossCrate::No),
ungated!(unsafe(Edition2024) export_name, Normal, template!(NameValueStr: "name"), FutureWarnPreceding, EncodeCrossCrate::No),
ungated!(unsafe(Edition2024) link_section, Normal, template!(NameValueStr: "name"), FutureWarnPreceding, EncodeCrossCrate::No),
ungated!(unsafe(Edition2024) no_mangle, Normal, template!(Word), WarnFollowing, EncodeCrossCrate::No),
ungated!(used, Normal, template!(Word, List: "compiler|linker"), WarnFollowing, EncodeCrossCrate::No),
ungated!(link_ordinal, Normal, template!(List: "ordinal"), ErrorPreceding, EncodeCrossCrate::Yes),

10
compiler/rustc_parse/src/validate_attr.rs
View file

@ -157,7 +157,7 @@ fn is_attr_template_compatible(template: &AttributeTemplate, meta: &ast::MetaIte
pub fn check_attribute_safety(psess: &ParseSess, safety: AttributeSafety, attr: &Attribute) {
let attr_item = attr.get_normal_item();
if safety == AttributeSafety::Unsafe {
if let AttributeSafety::Unsafe { unsafe_since } = safety {
if let ast::Safety::Default = attr_item.unsafety {
let path_span = attr_item.path.span;
@ -167,7 +167,13 @@ pub fn check_attribute_safety(psess: &ParseSess, safety: AttributeSafety, attr:
// square bracket respectively.
let diag_span = attr_item.span();
if attr.span.at_least_rust_2024() {
// Attributes can be safe in earlier editions, and become unsafe in later ones.
let emit_error = match unsafe_since {
None => true,
Some(unsafe_since) => attr.span.edition() >= unsafe_since,
};
if emit_error {
psess.dcx().emit_err(errors::UnsafeAttrOutsideUnsafe {
span: path_span,
suggestion: errors::UnsafeAttrOutsideUnsafeSuggestion {

2
tests/codegen/cffi/ffi-const.rs
View file

@ -10,6 +10,6 @@ extern "C" {
// CHECK-LABEL: declare{{.*}}void @foo()
// CHECK-SAME: [[ATTRS:#[0-9]+]]
// CHECK-DAG: attributes [[ATTRS]] = { {{.*}}memory(none){{.*}} }
#[ffi_const]
#[unsafe(ffi_const)]
pub fn foo();
}

2
tests/codegen/cffi/ffi-pure.rs
View file

@ -10,6 +10,6 @@ extern "C" {
// CHECK-LABEL: declare{{.*}}void @foo()
// CHECK-SAME: [[ATTRS:#[0-9]+]]
// CHECK-DAG: attributes [[ATTRS]] = { {{.*}}memory(read){{.*}} }
#[ffi_pure]
#[unsafe(ffi_pure)]
pub fn foo();
}

2
tests/ui/feature-gates/feature-gate-ffi_const.rs
View file

@ -1,6 +1,6 @@
#![crate_type = "lib"]
extern "C" {
#[ffi_const] //~ ERROR the `#[ffi_const]` attribute is an experimental feature
#[unsafe(ffi_const)] //~ ERROR the `#[ffi_const]` attribute is an experimental feature
pub fn foo();
}

4
tests/ui/feature-gates/feature-gate-ffi_const.stderr
View file

@ -1,8 +1,8 @@
error[E0658]: the `#[ffi_const]` attribute is an experimental feature
--> $DIR/feature-gate-ffi_const.rs:4:5
|
LL | #[ffi_const]
| ^^^^^^^^^^^^
LL | #[unsafe(ffi_const)]
| ^^^^^^^^^^^^^^^^^^^^
|
= note: see issue #58328 <https://github.com/rust-lang/rust/issues/58328> for more information
= help: add `#![feature(ffi_const)]` to the crate attributes to enable

2
tests/ui/feature-gates/feature-gate-ffi_pure.rs
View file

@ -1,6 +1,6 @@
#![crate_type = "lib"]
extern "C" {
#[ffi_pure] //~ ERROR the `#[ffi_pure]` attribute is an experimental feature
#[unsafe(ffi_pure)] //~ ERROR the `#[ffi_pure]` attribute is an experimental feature
pub fn foo();
}

4
tests/ui/feature-gates/feature-gate-ffi_pure.stderr
View file

@ -1,8 +1,8 @@
error[E0658]: the `#[ffi_pure]` attribute is an experimental feature
--> $DIR/feature-gate-ffi_pure.rs:4:5
|
LL | #[ffi_pure]
| ^^^^^^^^^^^
LL | #[unsafe(ffi_pure)]
| ^^^^^^^^^^^^^^^^^^^
|
= note: see issue #58329 <https://github.com/rust-lang/rust/issues/58329> for more information
= help: add `#![feature(ffi_pure)]` to the crate attributes to enable

11
tests/ui/ffi-attrs/ffi_const.rs
View file

@ -1,15 +1,18 @@
#![feature(ffi_const)]
#![crate_type = "lib"]
#[ffi_const] //~ ERROR `#[ffi_const]` may only be used on foreign functions
#[unsafe(ffi_const)] //~ ERROR `#[ffi_const]` may only be used on foreign functions
pub fn foo() {}
#[ffi_const] //~ ERROR `#[ffi_const]` may only be used on foreign functions
#[unsafe(ffi_const)] //~ ERROR `#[ffi_const]` may only be used on foreign functions
macro_rules! bar {
() => ()
() => {};
}
extern "C" {
#[ffi_const] //~ ERROR `#[ffi_const]` may only be used on foreign functions
#[unsafe(ffi_const)] //~ ERROR `#[ffi_const]` may only be used on foreign functions
static INT: i32;
#[ffi_const] //~ ERROR unsafe attribute used without unsafe
fn bar();
}

25
tests/ui/ffi-attrs/ffi_const.stderr
View file

@ -1,21 +1,32 @@
error: unsafe attribute used without unsafe
--> $DIR/ffi_const.rs:16:7
|
LL | #[ffi_const]
| ^^^^^^^^^ usage of unsafe attribute
|
help: wrap the attribute in `unsafe(...)`
|
LL | #[unsafe(ffi_const)]
| +++++++ +
error[E0756]: `#[ffi_const]` may only be used on foreign functions
--> $DIR/ffi_const.rs:4:1
|
LL | #[ffi_const]
| ^^^^^^^^^^^^
LL | #[unsafe(ffi_const)]
| ^^^^^^^^^^^^^^^^^^^^
error[E0756]: `#[ffi_const]` may only be used on foreign functions
--> $DIR/ffi_const.rs:7:1
|
LL | #[ffi_const]
| ^^^^^^^^^^^^
LL | #[unsafe(ffi_const)]
| ^^^^^^^^^^^^^^^^^^^^
error[E0756]: `#[ffi_const]` may only be used on foreign functions
--> $DIR/ffi_const.rs:13:5
|
LL | #[ffi_const]
| ^^^^^^^^^^^^
LL | #[unsafe(ffi_const)]
| ^^^^^^^^^^^^^^^^^^^^
error: aborting due to 3 previous errors
error: aborting due to 4 previous errors
For more information about this error, try `rustc --explain E0756`.

4
tests/ui/ffi-attrs/ffi_const2.rs
View file

@ -1,8 +1,8 @@
#![feature(ffi_const, ffi_pure)]
extern "C" {
#[ffi_pure] //~ ERROR `#[ffi_const]` function cannot be `#[ffi_pure]`
#[ffi_const]
#[unsafe(ffi_pure)] //~ ERROR `#[ffi_const]` function cannot be `#[ffi_pure]`
#[unsafe(ffi_const)]
pub fn baz();
}

4
tests/ui/ffi-attrs/ffi_const2.stderr
View file

@ -1,8 +1,8 @@
error[E0757]: `#[ffi_const]` function cannot be `#[ffi_pure]`
--> $DIR/ffi_const2.rs:4:5
|
LL | #[ffi_pure]
| ^^^^^^^^^^^
LL | #[unsafe(ffi_pure)]
| ^^^^^^^^^^^^^^^^^^^
error: aborting due to 1 previous error

11
tests/ui/ffi-attrs/ffi_pure.rs
View file

@ -1,15 +1,18 @@
#![feature(ffi_pure)]
#![crate_type = "lib"]
#[ffi_pure] //~ ERROR `#[ffi_pure]` may only be used on foreign functions
#[unsafe(ffi_pure)] //~ ERROR `#[ffi_pure]` may only be used on foreign functions
pub fn foo() {}
#[ffi_pure] //~ ERROR `#[ffi_pure]` may only be used on foreign functions
#[unsafe(ffi_pure)] //~ ERROR `#[ffi_pure]` may only be used on foreign functions
macro_rules! bar {
() => ()
() => {};
}
extern "C" {
#[ffi_pure] //~ ERROR `#[ffi_pure]` may only be used on foreign functions
#[unsafe(ffi_pure)] //~ ERROR `#[ffi_pure]` may only be used on foreign functions
static INT: i32;
#[ffi_pure] //~ ERROR unsafe attribute used without unsafe
fn bar();
}

25
tests/ui/ffi-attrs/ffi_pure.stderr
View file

@ -1,21 +1,32 @@
error: unsafe attribute used without unsafe
--> $DIR/ffi_pure.rs:16:7
|
LL | #[ffi_pure]
| ^^^^^^^^ usage of unsafe attribute
|
help: wrap the attribute in `unsafe(...)`
|
LL | #[unsafe(ffi_pure)]
| +++++++ +
error[E0755]: `#[ffi_pure]` may only be used on foreign functions
--> $DIR/ffi_pure.rs:4:1
|
LL | #[ffi_pure]
| ^^^^^^^^^^^
LL | #[unsafe(ffi_pure)]
| ^^^^^^^^^^^^^^^^^^^
error[E0755]: `#[ffi_pure]` may only be used on foreign functions
--> $DIR/ffi_pure.rs:7:1
|
LL | #[ffi_pure]
| ^^^^^^^^^^^
LL | #[unsafe(ffi_pure)]
| ^^^^^^^^^^^^^^^^^^^
error[E0755]: `#[ffi_pure]` may only be used on foreign functions
--> $DIR/ffi_pure.rs:13:5
|
LL | #[ffi_pure]
| ^^^^^^^^^^^
LL | #[unsafe(ffi_pure)]
| ^^^^^^^^^^^^^^^^^^^
error: aborting due to 3 previous errors
error: aborting due to 4 previous errors
For more information about this error, try `rustc --explain E0755`.