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rust/compiler/rustc_feature/src/builtin_attrs.rs
Jieyou Xu 69b71e4410 Mitigate #[align] name resolution ambiguity regression with a rename 
From `#[align]` -> `#[rustc_align]`. Attributes starting with `rustc`
are always perma-unstable and feature-gated by `feature(rustc_attrs)`.

See regression RUST-143834.

For the underlying problem where even introducing new feature-gated
unstable built-in attributes can break user code such as

```rs
macro_rules! align {
    () => {
        /* .. */
    };
}

pub(crate) use align; // `use` here becomes ambiguous
```

refer to RUST-134963.

Since the `#[align]` attribute is still feature-gated by
`feature(fn_align)`, we can rename it as a mitigation. Note that
`#[rustc_align]` will obviously mean that current unstable user code
using `feature(fn_aling)` will need additionally `feature(rustc_attrs)`,
but this is a short-term mitigation to buy time, and is expected to be
changed to a better name with less collision potential.

See
<https://rust-lang.zulipchat.com/#narrow/channel/238009-t-compiler.2Fmeetings/topic/.5Bweekly.5D.202025-07-17/near/529290371>
where mitigation options were considered.
2025-07-19 01:42:30 +08:00

1310 lines
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Rust
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//! Built-in attributes and `cfg` flag gating.
use std::sync::LazyLock;
use AttributeDuplicates::*;
use AttributeGate::*;
use AttributeType::*;
use rustc_attr_data_structures::EncodeCrossCrate;
use rustc_data_structures::fx::FxHashMap;
use rustc_span::edition::Edition;
use rustc_span::{Symbol, sym};
use crate::Features;
type GateFn = fn(&Features) -> bool;
pub type GatedCfg = (Symbol, Symbol, GateFn);
/// `cfg(...)`'s that are feature gated.
const GATED_CFGS: &[GatedCfg] = &[
// (name in cfg, feature, function to check if the feature is enabled)
(sym::overflow_checks, sym::cfg_overflow_checks, Features::cfg_overflow_checks),
(sym::ub_checks, sym::cfg_ub_checks, Features::cfg_ub_checks),
(sym::contract_checks, sym::cfg_contract_checks, Features::cfg_contract_checks),
(sym::target_thread_local, sym::cfg_target_thread_local, Features::cfg_target_thread_local),
(
sym::target_has_atomic_equal_alignment,
sym::cfg_target_has_atomic_equal_alignment,
Features::cfg_target_has_atomic_equal_alignment,
),
(
sym::target_has_atomic_load_store,
sym::cfg_target_has_atomic,
Features::cfg_target_has_atomic,
),
(sym::sanitize, sym::cfg_sanitize, Features::cfg_sanitize),
(sym::version, sym::cfg_version, Features::cfg_version),
(sym::relocation_model, sym::cfg_relocation_model, Features::cfg_relocation_model),
(sym::sanitizer_cfi_generalize_pointers, sym::cfg_sanitizer_cfi, Features::cfg_sanitizer_cfi),
(sym::sanitizer_cfi_normalize_integers, sym::cfg_sanitizer_cfi, Features::cfg_sanitizer_cfi),
// this is consistent with naming of the compiler flag it's for
(sym::fmt_debug, sym::fmt_debug, Features::fmt_debug),
(sym::emscripten_wasm_eh, sym::cfg_emscripten_wasm_eh, Features::cfg_emscripten_wasm_eh),
(
sym::target_has_reliable_f16,
sym::cfg_target_has_reliable_f16_f128,
Features::cfg_target_has_reliable_f16_f128,
),
(
sym::target_has_reliable_f16_math,
sym::cfg_target_has_reliable_f16_f128,
Features::cfg_target_has_reliable_f16_f128,
),
(
sym::target_has_reliable_f128,
sym::cfg_target_has_reliable_f16_f128,
Features::cfg_target_has_reliable_f16_f128,
),
(
sym::target_has_reliable_f128_math,
sym::cfg_target_has_reliable_f16_f128,
Features::cfg_target_has_reliable_f16_f128,
),
];
/// Find a gated cfg determined by the `pred`icate which is given the cfg's name.
pub fn find_gated_cfg(pred: impl Fn(Symbol) -> bool) -> Option<&'static GatedCfg> {
GATED_CFGS.iter().find(|(cfg_sym, ..)| pred(*cfg_sym))
}
// If you change this, please modify `src/doc/unstable-book` as well. You must
// move that documentation into the relevant place in the other docs, and
// remove the chapter on the flag.
#[derive(Copy, Clone, PartialEq, Debug)]
pub enum AttributeType {
/// Normal, builtin attribute that is consumed
/// by the compiler before the unused_attribute check
Normal,
/// Builtin attribute that is only allowed at the crate level
CrateLevel,
}
#[derive(Copy, Clone, PartialEq, Debug)]
pub enum AttributeSafety {
/// Normal attribute that does not need `#[unsafe(...)]`
Normal,
/// 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, Debug, Copy)]
pub enum AttributeGate {
/// A gated attribute which requires a feature gate to be enabled.
Gated {
/// The feature gate, for example `#![feature(rustc_attrs)]` for rustc_* attributes.
feature: Symbol,
/// The error message displayed when an attempt is made to use the attribute without its feature gate.
message: &'static str,
/// Check function to be called during the `PostExpansionVisitor` pass.
check: fn(&Features) -> bool,
/// Notes to be displayed when an attempt is made to use the attribute without its feature gate.
notes: &'static [&'static str],
},
/// Ungated attribute, can be used on all release channels
Ungated,
}
// FIXME(jdonszelmann): move to rustc_attr_data_structures
/// A template that the attribute input must match.
/// Only top-level shape (`#[attr]` vs `#[attr(...)]` vs `#[attr = ...]`) is considered now.
#[derive(Clone, Copy, Default)]
pub struct AttributeTemplate {
/// If `true`, the attribute is allowed to be a bare word like `#[test]`.
pub word: bool,
/// If `Some`, the attribute is allowed to take a list of items like `#[allow(..)]`.
pub list: Option<&'static str>,
/// If non-empty, the attribute is allowed to take a list containing exactly
/// one of the listed words, like `#[coverage(off)]`.
pub one_of: &'static [Symbol],
/// If `Some`, the attribute is allowed to be a name/value pair where the
/// value is a string, like `#[must_use = "reason"]`.
pub name_value_str: Option<&'static str>,
}
impl AttributeTemplate {
pub fn suggestions(&self, inner: bool, name: impl std::fmt::Display) -> Vec<String> {
let mut suggestions = vec![];
let inner = if inner { "!" } else { "" };
if self.word {
suggestions.push(format!("#{inner}[{name}]"));
}
if let Some(descr) = self.list {
suggestions.push(format!("#{inner}[{name}({descr})]"));
}
suggestions.extend(self.one_of.iter().map(|&word| format!("#{inner}[{name}({word})]")));
if let Some(descr) = self.name_value_str {
suggestions.push(format!("#{inner}[{name} = \"{descr}\"]"));
}
suggestions.sort();
suggestions
}
}
/// How to handle multiple duplicate attributes on the same item.
#[derive(Clone, Copy, Default)]
pub enum AttributeDuplicates {
/// Duplicates of this attribute are allowed.
///
/// This should only be used with attributes where duplicates have semantic
/// meaning, or some kind of "additive" behavior. For example, `#[warn(..)]`
/// can be specified multiple times, and it combines all the entries. Or use
/// this if there is validation done elsewhere.
#[default]
DuplicatesOk,
/// Duplicates after the first attribute will be an unused_attribute warning.
///
/// This is usually used for "word" attributes, where they are used as a
/// boolean marker, like `#[used]`. It is not necessarily wrong that there
/// are duplicates, but the others should probably be removed.
WarnFollowing,
/// Same as `WarnFollowing`, but only issues warnings for word-style attributes.
///
/// This is only for special cases, for example multiple `#[macro_use]` can
/// be warned, but multiple `#[macro_use(...)]` should not because the list
/// form has different meaning from the word form.
WarnFollowingWordOnly,
/// Duplicates after the first attribute will be an error.
///
/// This should be used where duplicates would be ignored, but carry extra
/// meaning that could cause confusion. For example, `#[stable(since="1.0")]
/// #[stable(since="2.0")]`, which version should be used for `stable`?
ErrorFollowing,
/// Duplicates preceding the last instance of the attribute will be an error.
///
/// This is the same as `ErrorFollowing`, except the last attribute is the
/// one that is "used". This is typically used in cases like codegen
/// attributes which usually only honor the last attribute.
ErrorPreceding,
/// Duplicates after the first attribute will be an unused_attribute warning
/// with a note that this will be an error in the future.
///
/// This should be used for attributes that should be `ErrorFollowing`, but
/// because older versions of rustc silently accepted (and ignored) the
/// attributes, this is used to transition.
FutureWarnFollowing,
/// Duplicates preceding the last instance of the attribute will be a
/// warning, with a note that this will be an error in the future.
///
/// This is the same as `FutureWarnFollowing`, except the last attribute is
/// the one that is "used". Ideally these can eventually migrate to
/// `ErrorPreceding`.
FutureWarnPreceding,
}
/// A convenience macro for constructing attribute templates.
/// E.g., `template!(Word, List: "description")` means that the attribute
/// supports forms `#[attr]` and `#[attr(description)]`.
#[macro_export]
macro_rules! template {
(Word) => { $crate::template!(@ true, None, &[], None) };
(List: $descr: expr) => { $crate::template!(@ false, Some($descr), &[], None) };
(OneOf: $one_of: expr) => { $crate::template!(@ false, None, $one_of, None) };
(NameValueStr: $descr: expr) => { $crate::template!(@ false, None, &[], Some($descr)) };
(Word, List: $descr: expr) => { $crate::template!(@ true, Some($descr), &[], None) };
(Word, NameValueStr: $descr: expr) => { $crate::template!(@ true, None, &[], Some($descr)) };
(List: $descr1: expr, NameValueStr: $descr2: expr) => {
$crate::template!(@ false, Some($descr1), &[], Some($descr2))
};
(Word, List: $descr1: expr, NameValueStr: $descr2: expr) => {
$crate::template!(@ true, Some($descr1), &[], Some($descr2))
};
(@ $word: expr, $list: expr, $one_of: expr, $name_value_str: expr) => { $crate::AttributeTemplate {
word: $word, list: $list, one_of: $one_of, name_value_str: $name_value_str
} };
}
macro_rules! ungated {
(unsafe($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 { unsafe_since: None },
template: $tpl,
gate: Ungated,
duplicates: $duplicates,
}
};
($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::Normal,
template: $tpl,
gate: Ungated,
duplicates: $duplicates,
}
};
}
macro_rules! gated {
(unsafe $attr:ident, $typ:expr, $tpl:expr, $duplicates:expr, $encode_cross_crate:expr, $gate:ident, $message:expr $(,)?) => {
BuiltinAttribute {
name: sym::$attr,
encode_cross_crate: $encode_cross_crate,
type_: $typ,
safety: AttributeSafety::Unsafe { unsafe_since: None },
template: $tpl,
duplicates: $duplicates,
gate: Gated {
feature: sym::$gate,
message: $message,
check: Features::$gate,
notes: &[],
},
}
};
(unsafe $attr:ident, $typ:expr, $tpl:expr, $duplicates:expr, $encode_cross_crate:expr, $message:expr $(,)?) => {
BuiltinAttribute {
name: sym::$attr,
encode_cross_crate: $encode_cross_crate,
type_: $typ,
safety: AttributeSafety::Unsafe { unsafe_since: None },
template: $tpl,
duplicates: $duplicates,
gate: Gated {
feature: sym::$attr,
message: $message,
check: Features::$attr,
notes: &[],
},
}
};
($attr:ident, $typ:expr, $tpl:expr, $duplicates:expr, $encode_cross_crate:expr, $gate:ident, $message:expr $(,)?) => {
BuiltinAttribute {
name: sym::$attr,
encode_cross_crate: $encode_cross_crate,
type_: $typ,
safety: AttributeSafety::Normal,
template: $tpl,
duplicates: $duplicates,
gate: Gated {
feature: sym::$gate,
message: $message,
check: Features::$gate,
notes: &[],
},
}
};
($attr:ident, $typ:expr, $tpl:expr, $duplicates:expr, $encode_cross_crate:expr, $message:expr $(,)?) => {
BuiltinAttribute {
name: sym::$attr,
encode_cross_crate: $encode_cross_crate,
type_: $typ,
safety: AttributeSafety::Normal,
template: $tpl,
duplicates: $duplicates,
gate: Gated {
feature: sym::$attr,
message: $message,
check: Features::$attr,
notes: &[],
},
}
};
}
macro_rules! rustc_attr {
(TEST, $attr:ident, $typ:expr, $tpl:expr, $duplicate:expr, $encode_cross_crate:expr $(,)?) => {
rustc_attr!(
$attr,
$typ,
$tpl,
$duplicate,
$encode_cross_crate,
concat!(
"the `#[",
stringify!($attr),
"]` attribute is used for rustc unit tests"
),
)
};
($attr:ident, $typ:expr, $tpl:expr, $duplicates:expr, $encode_cross_crate:expr, $($notes:expr),* $(,)?) => {
BuiltinAttribute {
name: sym::$attr,
encode_cross_crate: $encode_cross_crate,
type_: $typ,
safety: AttributeSafety::Normal,
template: $tpl,
duplicates: $duplicates,
gate: Gated {
feature: sym::rustc_attrs,
message: "use of an internal attribute",
check: Features::rustc_attrs,
notes: &[
concat!("the `#[",
stringify!($attr),
"]` attribute is an internal implementation detail that will never be stable"),
$($notes),*
]
},
}
};
}
macro_rules! experimental {
($attr:ident) => {
concat!("the `#[", stringify!($attr), "]` attribute is an experimental feature")
};
}
pub struct BuiltinAttribute {
pub name: Symbol,
/// Whether this attribute is encode cross crate.
///
/// If so, it is encoded in the crate metadata.
/// Otherwise, it can only be used in the local crate.
pub encode_cross_crate: EncodeCrossCrate,
pub type_: AttributeType,
pub safety: AttributeSafety,
pub template: AttributeTemplate,
pub duplicates: AttributeDuplicates,
pub gate: AttributeGate,
}
/// Attributes that have a special meaning to rustc or rustdoc.
#[rustfmt::skip]
pub static BUILTIN_ATTRIBUTES: &[BuiltinAttribute] = &[
// ==========================================================================
// Stable attributes:
// ==========================================================================
// Conditional compilation:
ungated!(cfg, Normal, template!(List: "predicate"), DuplicatesOk, EncodeCrossCrate::Yes),
ungated!(cfg_attr, Normal, template!(List: "predicate, attr1, attr2, ..."), DuplicatesOk, EncodeCrossCrate::Yes),
// Testing:
ungated!(
ignore, Normal, template!(Word, NameValueStr: "reason"), WarnFollowing,
EncodeCrossCrate::No,
),
ungated!(
should_panic, Normal,
template!(Word, List: r#"expected = "reason""#, NameValueStr: "reason"), FutureWarnFollowing,
EncodeCrossCrate::No,
),
// FIXME(Centril): This can be used on stable but shouldn't.
ungated!(
reexport_test_harness_main, CrateLevel, template!(NameValueStr: "name"), ErrorFollowing,
EncodeCrossCrate::No,
),
// Macros:
ungated!(automatically_derived, Normal, template!(Word), WarnFollowing, EncodeCrossCrate::Yes),
ungated!(
macro_use, Normal, template!(Word, List: "name1, name2, ..."), WarnFollowingWordOnly,
EncodeCrossCrate::No,
),
ungated!(macro_escape, Normal, template!(Word), WarnFollowing, EncodeCrossCrate::No), // Deprecated synonym for `macro_use`.
ungated!(
macro_export, Normal, template!(Word, List: "local_inner_macros"),
WarnFollowing, EncodeCrossCrate::Yes
),
ungated!(proc_macro, Normal, template!(Word), ErrorFollowing, EncodeCrossCrate::No),
ungated!(
proc_macro_derive, Normal, template!(List: "TraitName, /*opt*/ attributes(name1, name2, ...)"),
ErrorFollowing, EncodeCrossCrate::No,
),
ungated!(proc_macro_attribute, Normal, template!(Word), ErrorFollowing, EncodeCrossCrate::No),
// Lints:
ungated!(
warn, Normal, template!(List: r#"lint1, lint2, ..., /*opt*/ reason = "...""#),
DuplicatesOk, EncodeCrossCrate::No,
),
ungated!(
allow, Normal, template!(List: r#"lint1, lint2, ..., /*opt*/ reason = "...""#),
DuplicatesOk, EncodeCrossCrate::No,
),
ungated!(
expect, Normal, template!(List: r#"lint1, lint2, ..., /*opt*/ reason = "...""#),
DuplicatesOk, EncodeCrossCrate::No,
),
ungated!(
forbid, Normal, template!(List: r#"lint1, lint2, ..., /*opt*/ reason = "...""#),
DuplicatesOk, EncodeCrossCrate::No
),
ungated!(
deny, Normal, template!(List: r#"lint1, lint2, ..., /*opt*/ reason = "...""#),
DuplicatesOk, EncodeCrossCrate::No
),
ungated!(
must_use, Normal, template!(Word, NameValueStr: "reason"),
FutureWarnFollowing, EncodeCrossCrate::Yes
),
gated!(
must_not_suspend, Normal, template!(Word, NameValueStr: "reason"), WarnFollowing,
EncodeCrossCrate::Yes, experimental!(must_not_suspend)
),
ungated!(
deprecated, Normal,
template!(
Word,
List: r#"/*opt*/ since = "version", /*opt*/ note = "reason""#,
NameValueStr: "reason"
),
ErrorFollowing, EncodeCrossCrate::Yes
),
// Crate properties:
ungated!(
crate_name, CrateLevel, template!(NameValueStr: "name"), FutureWarnFollowing,
EncodeCrossCrate::No,
),
ungated!(
crate_type, CrateLevel, template!(NameValueStr: "bin|lib|..."), DuplicatesOk,
EncodeCrossCrate::No,
),
// ABI, linking, symbols, and FFI
ungated!(
link, Normal,
template!(List: r#"name = "...", /*opt*/ kind = "dylib|static|...", /*opt*/ wasm_import_module = "...", /*opt*/ import_name_type = "decorated|noprefix|undecorated""#),
DuplicatesOk,
EncodeCrossCrate::No,
),
ungated!(
link_name, Normal, template!(NameValueStr: "name"),
FutureWarnPreceding, EncodeCrossCrate::Yes
),
ungated!(no_link, Normal, template!(Word), WarnFollowing, EncodeCrossCrate::No),
ungated!(repr, Normal, template!(List: "C"), DuplicatesOk, EncodeCrossCrate::No),
// FIXME(#82232, #143834): temporarily renamed to mitigate `#[align]` nameres ambiguity
gated!(rustc_align, Normal, template!(List: "alignment"), DuplicatesOk, EncodeCrossCrate::No, fn_align, experimental!(rustc_align)),
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),
ungated!(unsafe naked, Normal, template!(Word), WarnFollowing, EncodeCrossCrate::No),
// Limits:
ungated!(
recursion_limit, CrateLevel, template!(NameValueStr: "N"), FutureWarnFollowing,
EncodeCrossCrate::No
),
ungated!(
type_length_limit, CrateLevel, template!(NameValueStr: "N"), FutureWarnFollowing,
EncodeCrossCrate::No
),
gated!(
move_size_limit, CrateLevel, template!(NameValueStr: "N"), ErrorFollowing,
EncodeCrossCrate::No, large_assignments, experimental!(move_size_limit)
),
// Entry point:
ungated!(no_main, CrateLevel, template!(Word), WarnFollowing, EncodeCrossCrate::No),
// Modules, prelude, and resolution:
ungated!(path, Normal, template!(NameValueStr: "file"), FutureWarnFollowing, EncodeCrossCrate::No),
ungated!(no_std, CrateLevel, template!(Word), WarnFollowing, EncodeCrossCrate::No),
ungated!(no_implicit_prelude, Normal, template!(Word), WarnFollowing, EncodeCrossCrate::No),
ungated!(non_exhaustive, Normal, template!(Word), WarnFollowing, EncodeCrossCrate::Yes),
// Runtime
ungated!(
windows_subsystem, CrateLevel,
template!(NameValueStr: "windows|console"), FutureWarnFollowing,
EncodeCrossCrate::No
),
ungated!(panic_handler, Normal, template!(Word), WarnFollowing, EncodeCrossCrate::Yes), // RFC 2070
// Code generation:
ungated!(inline, Normal, template!(Word, List: "always|never"), FutureWarnFollowing, EncodeCrossCrate::No),
ungated!(cold, Normal, template!(Word), WarnFollowing, EncodeCrossCrate::No),
ungated!(no_builtins, CrateLevel, template!(Word), WarnFollowing, EncodeCrossCrate::Yes),
ungated!(
target_feature, Normal, template!(List: r#"enable = "name""#),
DuplicatesOk, EncodeCrossCrate::No,
),
ungated!(track_caller, Normal, template!(Word), WarnFollowing, EncodeCrossCrate::Yes),
ungated!(instruction_set, Normal, template!(List: "set"), ErrorPreceding, EncodeCrossCrate::No),
gated!(
no_sanitize, Normal,
template!(List: "address, kcfi, memory, thread"), DuplicatesOk,
EncodeCrossCrate::No, experimental!(no_sanitize)
),
gated!(
coverage, Normal, template!(OneOf: &[sym::off, sym::on]),
ErrorPreceding, EncodeCrossCrate::No,
coverage_attribute, experimental!(coverage)
),
ungated!(
doc, Normal, template!(List: "hidden|inline|...", NameValueStr: "string"), DuplicatesOk,
EncodeCrossCrate::Yes
),
// Debugging
ungated!(
debugger_visualizer, Normal,
template!(List: r#"natvis_file = "...", gdb_script_file = "...""#),
DuplicatesOk, EncodeCrossCrate::No
),
ungated!(collapse_debuginfo, Normal, template!(List: "no|external|yes"), ErrorFollowing,
EncodeCrossCrate::Yes
),
// ==========================================================================
// Unstable attributes:
// ==========================================================================
// Linking:
gated!(
export_stable, Normal, template!(Word), WarnFollowing,
EncodeCrossCrate::No, experimental!(export_stable)
),
// Testing:
gated!(
test_runner, CrateLevel, template!(List: "path"), ErrorFollowing,
EncodeCrossCrate::Yes, custom_test_frameworks,
"custom test frameworks are an unstable feature",
),
// RFC #1268
gated!(
marker, Normal, template!(Word), WarnFollowing, EncodeCrossCrate::No,
marker_trait_attr, experimental!(marker)
),
gated!(
thread_local, Normal, template!(Word), WarnFollowing, EncodeCrossCrate::No,
"`#[thread_local]` is an experimental feature, and does not currently handle destructors",
),
gated!(
no_core, CrateLevel, template!(Word), WarnFollowing,
EncodeCrossCrate::No, experimental!(no_core)
),
// RFC 2412
gated!(
optimize, Normal, template!(List: "none|size|speed"), ErrorPreceding,
EncodeCrossCrate::No, optimize_attribute, experimental!(optimize)
),
gated!(
unsafe ffi_pure, Normal, template!(Word), WarnFollowing,
EncodeCrossCrate::No, experimental!(ffi_pure)
),
gated!(
unsafe ffi_const, Normal, template!(Word), WarnFollowing,
EncodeCrossCrate::No, experimental!(ffi_const)
),
gated!(
register_tool, CrateLevel, template!(List: "tool1, tool2, ..."), DuplicatesOk,
EncodeCrossCrate::No, experimental!(register_tool),
),
// RFC 2632
// FIXME(const_trait_impl) remove this
gated!(
const_trait, Normal, template!(Word), WarnFollowing, EncodeCrossCrate::No, const_trait_impl,
"`const_trait` is a temporary placeholder for marking a trait that is suitable for `const` \
`impls` and all default bodies as `const`, which may be removed or renamed in the \
future."
),
// lang-team MCP 147
gated!(
deprecated_safe, Normal, template!(List: r#"since = "version", note = "...""#), ErrorFollowing,
EncodeCrossCrate::Yes, experimental!(deprecated_safe),
),
// `#[cfi_encoding = ""]`
gated!(
cfi_encoding, Normal, template!(NameValueStr: "encoding"), ErrorPreceding,
EncodeCrossCrate::Yes, experimental!(cfi_encoding)
),
// `#[coroutine]` attribute to be applied to closures to make them coroutines instead
gated!(
coroutine, Normal, template!(Word), ErrorFollowing,
EncodeCrossCrate::No, coroutines, experimental!(coroutine)
),
// RFC 3543
// `#[patchable_function_entry(prefix_nops = m, entry_nops = n)]`
gated!(
patchable_function_entry, Normal, template!(List: "prefix_nops = m, entry_nops = n"), ErrorPreceding,
EncodeCrossCrate::Yes, experimental!(patchable_function_entry)
),
// Probably temporary component of min_generic_const_args.
// `#[type_const] const ASSOC: usize;`
gated!(
type_const, Normal, template!(Word), ErrorFollowing,
EncodeCrossCrate::Yes, min_generic_const_args, experimental!(type_const),
),
// The `#[loop_match]` and `#[const_continue]` attributes are part of the
// lang experiment for RFC 3720 tracked in:
//
// - https://github.com/rust-lang/rust/issues/132306
gated!(
const_continue, Normal, template!(Word), ErrorFollowing,
EncodeCrossCrate::No, loop_match, experimental!(const_continue)
),
gated!(
loop_match, Normal, template!(Word), ErrorFollowing,
EncodeCrossCrate::No, loop_match, experimental!(loop_match)
),
// ==========================================================================
// Internal attributes: Stability, deprecation, and unsafe:
// ==========================================================================
ungated!(
feature, CrateLevel,
template!(List: "name1, name2, ..."), DuplicatesOk, EncodeCrossCrate::No,
),
// DuplicatesOk since it has its own validation
ungated!(
stable, Normal,
template!(List: r#"feature = "name", since = "version""#), DuplicatesOk, EncodeCrossCrate::No,
),
ungated!(
unstable, Normal,
template!(List: r#"feature = "name", reason = "...", issue = "N""#), DuplicatesOk,
EncodeCrossCrate::Yes
),
ungated!(
unstable_feature_bound, Normal, template!(Word, List: "feat1, feat2, ..."),
DuplicatesOk, EncodeCrossCrate::No,
),
ungated!(
rustc_const_unstable, Normal, template!(List: r#"feature = "name""#),
DuplicatesOk, EncodeCrossCrate::Yes
),
ungated!(
rustc_const_stable, Normal,
template!(List: r#"feature = "name""#), DuplicatesOk, EncodeCrossCrate::No,
),
ungated!(
rustc_default_body_unstable, Normal,
template!(List: r#"feature = "name", reason = "...", issue = "N""#),
DuplicatesOk, EncodeCrossCrate::No
),
gated!(
allow_internal_unstable, Normal, template!(Word, List: "feat1, feat2, ..."),
DuplicatesOk, EncodeCrossCrate::Yes,
"allow_internal_unstable side-steps feature gating and stability checks",
),
gated!(
allow_internal_unsafe, Normal, template!(Word), WarnFollowing,
EncodeCrossCrate::No, "allow_internal_unsafe side-steps the unsafe_code lint",
),
rustc_attr!(
rustc_allowed_through_unstable_modules, Normal, template!(NameValueStr: "deprecation message"),
WarnFollowing, EncodeCrossCrate::No,
"rustc_allowed_through_unstable_modules special cases accidental stabilizations of stable items \
through unstable paths"
),
rustc_attr!(
rustc_deprecated_safe_2024, Normal, template!(List: r#"audit_that = "...""#),
ErrorFollowing, EncodeCrossCrate::Yes,
"`#[rustc_deprecated_safe_2024]` is used to declare functions unsafe across the edition 2024 boundary",
),
rustc_attr!(
rustc_pub_transparent, Normal, template!(Word),
ErrorFollowing, EncodeCrossCrate::Yes,
"used internally to mark types with a `transparent` representation when it is guaranteed by the documentation",
),
// ==========================================================================
// Internal attributes: Type system related:
// ==========================================================================
gated!(fundamental, Normal, template!(Word), WarnFollowing, EncodeCrossCrate::Yes, experimental!(fundamental)),
gated!(
may_dangle, Normal, template!(Word), WarnFollowing,
EncodeCrossCrate::No, dropck_eyepatch,
"`may_dangle` has unstable semantics and may be removed in the future",
),
rustc_attr!(
rustc_never_type_options,
Normal,
template!(List: r#"/*opt*/ fallback = "unit|niko|never|no""#),
ErrorFollowing,
EncodeCrossCrate::No,
"`rustc_never_type_options` is used to experiment with never type fallback and work on \
never type stabilization"
),
// ==========================================================================
// Internal attributes: Runtime related:
// ==========================================================================
rustc_attr!(
rustc_allocator, Normal, template!(Word), WarnFollowing,
EncodeCrossCrate::No,
),
rustc_attr!(
rustc_nounwind, Normal, template!(Word), WarnFollowing,
EncodeCrossCrate::No,
),
rustc_attr!(
rustc_reallocator, Normal, template!(Word), WarnFollowing,
EncodeCrossCrate::No,
),
rustc_attr!(
rustc_deallocator, Normal, template!(Word), WarnFollowing,
EncodeCrossCrate::No,
),
rustc_attr!(
rustc_allocator_zeroed, Normal, template!(Word), WarnFollowing,
EncodeCrossCrate::No,
),
gated!(
default_lib_allocator, Normal, template!(Word), WarnFollowing,
EncodeCrossCrate::No, allocator_internals, experimental!(default_lib_allocator),
),
gated!(
needs_allocator, Normal, template!(Word), WarnFollowing,
EncodeCrossCrate::No, allocator_internals, experimental!(needs_allocator),
),
gated!(
panic_runtime, CrateLevel, template!(Word), WarnFollowing,
EncodeCrossCrate::No, experimental!(panic_runtime)
),
gated!(
needs_panic_runtime, CrateLevel, template!(Word), WarnFollowing,
EncodeCrossCrate::No, experimental!(needs_panic_runtime)
),
gated!(
compiler_builtins, CrateLevel, template!(Word), WarnFollowing,
EncodeCrossCrate::No,
"the `#[compiler_builtins]` attribute is used to identify the `compiler_builtins` crate \
which contains compiler-rt intrinsics and will never be stable",
),
gated!(
profiler_runtime, CrateLevel, template!(Word), WarnFollowing,
EncodeCrossCrate::No,
"the `#[profiler_runtime]` attribute is used to identify the `profiler_builtins` crate \
which contains the profiler runtime and will never be stable",
),
// ==========================================================================
// Internal attributes, Linkage:
// ==========================================================================
gated!(
linkage, Normal, template!(NameValueStr: "external|internal|..."),
ErrorPreceding, EncodeCrossCrate::No,
"the `linkage` attribute is experimental and not portable across platforms",
),
rustc_attr!(
rustc_std_internal_symbol, Normal, template!(Word), WarnFollowing,
EncodeCrossCrate::No,
),
// ==========================================================================
// Internal attributes, Macro related:
// ==========================================================================
rustc_attr!(
rustc_builtin_macro, Normal,
template!(Word, List: "name, /*opt*/ attributes(name1, name2, ...)"), ErrorFollowing,
EncodeCrossCrate::Yes,
),
rustc_attr!(
rustc_proc_macro_decls, Normal, template!(Word), WarnFollowing,
EncodeCrossCrate::No,
),
rustc_attr!(
rustc_macro_transparency, Normal,
template!(NameValueStr: "transparent|semiopaque|opaque"), ErrorFollowing,
EncodeCrossCrate::Yes, "used internally for testing macro hygiene",
),
rustc_attr!(
rustc_autodiff, Normal,
template!(Word, List: r#""...""#), DuplicatesOk,
EncodeCrossCrate::Yes,
),
// Traces that are left when `cfg` and `cfg_attr` attributes are expanded.
// The attributes are not gated, to avoid stability errors, but they cannot be used in stable
// or unstable code directly because `sym::cfg_(attr_)trace` are not valid identifiers, they
// can only be generated by the compiler.
ungated!(
cfg_trace, Normal, template!(Word /* irrelevant */), DuplicatesOk,
EncodeCrossCrate::No
),
ungated!(
cfg_attr_trace, Normal, template!(Word /* irrelevant */), DuplicatesOk,
EncodeCrossCrate::No
),
// ==========================================================================
// Internal attributes, Diagnostics related:
// ==========================================================================
rustc_attr!(
rustc_on_unimplemented, Normal,
template!(
List: r#"/*opt*/ message = "...", /*opt*/ label = "...", /*opt*/ note = "...""#,
NameValueStr: "message"
),
ErrorFollowing, EncodeCrossCrate::Yes,
"see `#[diagnostic::on_unimplemented]` for the stable equivalent of this attribute"
),
rustc_attr!(
rustc_confusables, Normal,
template!(List: r#""name1", "name2", ..."#),
ErrorFollowing, EncodeCrossCrate::Yes,
),
// Enumerates "identity-like" conversion methods to suggest on type mismatch.
rustc_attr!(
rustc_conversion_suggestion, Normal, template!(Word),
WarnFollowing, EncodeCrossCrate::Yes,
),
// Prevents field reads in the marked trait or method to be considered
// during dead code analysis.
rustc_attr!(
rustc_trivial_field_reads, Normal, template!(Word),
WarnFollowing, EncodeCrossCrate::Yes,
),
// Used by the `rustc::potential_query_instability` lint to warn methods which
// might not be stable during incremental compilation.
rustc_attr!(
rustc_lint_query_instability, Normal, template!(Word),
WarnFollowing, EncodeCrossCrate::Yes,
),
// Used by the `rustc::untracked_query_information` lint to warn methods which
// might not be stable during incremental compilation.
rustc_attr!(
rustc_lint_untracked_query_information, Normal, template!(Word),
WarnFollowing, EncodeCrossCrate::Yes,
),
// Used by the `rustc::diagnostic_outside_of_impl` lints to assist in changes to diagnostic
// APIs. Any function with this attribute will be checked by that lint.
rustc_attr!(
rustc_lint_diagnostics, Normal, template!(Word),
WarnFollowing, EncodeCrossCrate::Yes,
),
// Used by the `rustc::bad_opt_access` lint to identify `DebuggingOptions` and `CodegenOptions`
// types (as well as any others in future).
rustc_attr!(
rustc_lint_opt_ty, Normal, template!(Word),
WarnFollowing, EncodeCrossCrate::Yes,
),
// Used by the `rustc::bad_opt_access` lint on fields
// types (as well as any others in future).
rustc_attr!(
rustc_lint_opt_deny_field_access, Normal, template!(List: "message"),
WarnFollowing, EncodeCrossCrate::Yes,
),
// ==========================================================================
// Internal attributes, Const related:
// ==========================================================================
rustc_attr!(
rustc_promotable, Normal, template!(Word), WarnFollowing,
EncodeCrossCrate::No, ),
rustc_attr!(
rustc_legacy_const_generics, Normal, template!(List: "N"), ErrorFollowing,
EncodeCrossCrate::Yes,
),
// Do not const-check this function's body. It will always get replaced during CTFE via `hook_special_const_fn`.
rustc_attr!(
rustc_do_not_const_check, Normal, template!(Word), WarnFollowing,
EncodeCrossCrate::Yes, "`#[rustc_do_not_const_check]` skips const-check for this function's body",
),
rustc_attr!(
rustc_const_panic_str, Normal, template!(Word), WarnFollowing,
EncodeCrossCrate::Yes, "`#[rustc_const_panic_str]` ensures the argument to this function is &&str during const-check",
),
rustc_attr!(
rustc_const_stable_indirect, Normal,
template!(Word),
WarnFollowing,
EncodeCrossCrate::No,
"this is an internal implementation detail",
),
rustc_attr!(
rustc_intrinsic_const_stable_indirect, Normal,
template!(Word), WarnFollowing, EncodeCrossCrate::No, "this is an internal implementation detail",
),
gated!(
rustc_allow_const_fn_unstable, Normal,
template!(Word, List: "feat1, feat2, ..."), DuplicatesOk, EncodeCrossCrate::No,
"rustc_allow_const_fn_unstable side-steps feature gating and stability checks"
),
// ==========================================================================
// Internal attributes, Layout related:
// ==========================================================================
rustc_attr!(
rustc_layout_scalar_valid_range_start, Normal, template!(List: "value"), ErrorFollowing,
EncodeCrossCrate::Yes,
"the `#[rustc_layout_scalar_valid_range_start]` attribute is just used to enable \
niche optimizations in the standard library",
),
rustc_attr!(
rustc_layout_scalar_valid_range_end, Normal, template!(List: "value"), ErrorFollowing,
EncodeCrossCrate::Yes,
"the `#[rustc_layout_scalar_valid_range_end]` attribute is just used to enable \
niche optimizations in the standard library",
),
rustc_attr!(
rustc_nonnull_optimization_guaranteed, Normal, template!(Word), WarnFollowing,
EncodeCrossCrate::Yes,
"the `#[rustc_nonnull_optimization_guaranteed]` attribute is just used to document \
guaranteed niche optimizations in the standard library",
"the compiler does not even check whether the type indeed is being non-null-optimized; \
it is your responsibility to ensure that the attribute is only used on types that are optimized",
),
// ==========================================================================
// Internal attributes, Misc:
// ==========================================================================
gated!(
lang, Normal, template!(NameValueStr: "name"), DuplicatesOk, EncodeCrossCrate::No, lang_items,
"lang items are subject to change",
),
rustc_attr!(
rustc_as_ptr, Normal, template!(Word), ErrorFollowing,
EncodeCrossCrate::Yes,
"`#[rustc_as_ptr]` is used to mark functions returning pointers to their inner allocations."
),
rustc_attr!(
rustc_pass_by_value, Normal, template!(Word), ErrorFollowing,
EncodeCrossCrate::Yes,
"`#[rustc_pass_by_value]` is used to mark types that must be passed by value instead of reference."
),
rustc_attr!(
rustc_never_returns_null_ptr, Normal, template!(Word), ErrorFollowing,
EncodeCrossCrate::Yes,
"`#[rustc_never_returns_null_ptr]` is used to mark functions returning non-null pointers."
),
rustc_attr!(
rustc_no_implicit_autorefs, AttributeType::Normal, template!(Word), ErrorFollowing, EncodeCrossCrate::Yes,
"`#[rustc_no_implicit_autorefs]` is used to mark functions for which an autoref to the dereference of a raw pointer should not be used as an argument."
),
rustc_attr!(
rustc_coherence_is_core, AttributeType::CrateLevel, template!(Word), ErrorFollowing, EncodeCrossCrate::No,
"`#![rustc_coherence_is_core]` allows inherent methods on builtin types, only intended to be used in `core`."
),
rustc_attr!(
rustc_coinductive, AttributeType::Normal, template!(Word), WarnFollowing, EncodeCrossCrate::No,
"`#[rustc_coinductive]` changes a trait to be coinductive, allowing cycles in the trait solver."
),
rustc_attr!(
rustc_allow_incoherent_impl, AttributeType::Normal, template!(Word), ErrorFollowing, EncodeCrossCrate::No,
"`#[rustc_allow_incoherent_impl]` has to be added to all impl items of an incoherent inherent impl."
),
rustc_attr!(
rustc_preserve_ub_checks, AttributeType::CrateLevel, template!(Word), ErrorFollowing, EncodeCrossCrate::No,
"`#![rustc_preserve_ub_checks]` prevents the designated crate from evaluating whether UB checks are enabled when optimizing MIR",
),
rustc_attr!(
rustc_deny_explicit_impl,
AttributeType::Normal,
template!(Word),
ErrorFollowing,
EncodeCrossCrate::No,
"`#[rustc_deny_explicit_impl]` enforces that a trait can have no user-provided impls"
),
rustc_attr!(
rustc_do_not_implement_via_object,
AttributeType::Normal,
template!(Word),
ErrorFollowing,
EncodeCrossCrate::No,
"`#[rustc_do_not_implement_via_object]` opts out of the automatic trait impl for trait objects \
(`impl Trait for dyn Trait`)"
),
rustc_attr!(
rustc_has_incoherent_inherent_impls, AttributeType::Normal, template!(Word),
ErrorFollowing, EncodeCrossCrate::Yes,
"`#[rustc_has_incoherent_inherent_impls]` allows the addition of incoherent inherent impls for \
the given type by annotating all impl items with `#[rustc_allow_incoherent_impl]`."
),
BuiltinAttribute {
name: sym::rustc_diagnostic_item,
// FIXME: This can be `true` once we always use `tcx.is_diagnostic_item`.
encode_cross_crate: EncodeCrossCrate::Yes,
type_: Normal,
safety: AttributeSafety::Normal,
template: template!(NameValueStr: "name"),
duplicates: ErrorFollowing,
gate: Gated{
feature: sym::rustc_attrs,
message: "use of an internal attribute",
check: Features::rustc_attrs,
notes: &["the `#[rustc_diagnostic_item]` attribute allows the compiler to reference types \
from the standard library for diagnostic purposes"],
},
},
gated!(
// Used in resolve:
prelude_import, Normal, template!(Word), WarnFollowing,
EncodeCrossCrate::No, "`#[prelude_import]` is for use by rustc only",
),
gated!(
rustc_paren_sugar, Normal, template!(Word), WarnFollowing, EncodeCrossCrate::No,
unboxed_closures, "unboxed_closures are still evolving",
),
rustc_attr!(
rustc_inherit_overflow_checks, Normal, template!(Word), WarnFollowing, EncodeCrossCrate::No,
"the `#[rustc_inherit_overflow_checks]` attribute is just used to control \
overflow checking behavior of several functions in the standard library that are inlined \
across crates",
),
rustc_attr!(
rustc_reservation_impl, Normal,
template!(NameValueStr: "reservation message"), ErrorFollowing, EncodeCrossCrate::Yes,
"the `#[rustc_reservation_impl]` attribute is internally used \
for reserving `impl<T> From<!> for T` as part of the effort to stabilize `!`"
),
rustc_attr!(
rustc_test_marker, Normal, template!(NameValueStr: "name"), WarnFollowing,
EncodeCrossCrate::No, "the `#[rustc_test_marker]` attribute is used internally to track tests",
),
rustc_attr!(
rustc_unsafe_specialization_marker, Normal, template!(Word),
WarnFollowing, EncodeCrossCrate::No,
"the `#[rustc_unsafe_specialization_marker]` attribute is used to check specializations"
),
rustc_attr!(
rustc_specialization_trait, Normal, template!(Word),
WarnFollowing, EncodeCrossCrate::No,
"the `#[rustc_specialization_trait]` attribute is used to check specializations"
),
rustc_attr!(
rustc_main, Normal, template!(Word), WarnFollowing, EncodeCrossCrate::No,
"the `#[rustc_main]` attribute is used internally to specify test entry point function",
),
rustc_attr!(
rustc_skip_during_method_dispatch, Normal, template!(List: "array, boxed_slice"), ErrorFollowing,
EncodeCrossCrate::No,
"the `#[rustc_skip_during_method_dispatch]` attribute is used to exclude a trait \
from method dispatch when the receiver is of the following type, for compatibility in \
editions < 2021 (array) or editions < 2024 (boxed_slice)."
),
rustc_attr!(
rustc_must_implement_one_of, Normal, template!(List: "function1, function2, ..."),
ErrorFollowing, EncodeCrossCrate::No,
"the `#[rustc_must_implement_one_of]` attribute is used to change minimal complete \
definition of a trait. Its syntax and semantics are highly experimental and will be \
subject to change before stabilization",
),
rustc_attr!(
rustc_doc_primitive, Normal, template!(NameValueStr: "primitive name"), ErrorFollowing,
EncodeCrossCrate::Yes, "the `#[rustc_doc_primitive]` attribute is used by the standard library \
to provide a way to generate documentation for primitive types",
),
gated!(
rustc_intrinsic, Normal, template!(Word), ErrorFollowing, EncodeCrossCrate::Yes, intrinsics,
"the `#[rustc_intrinsic]` attribute is used to declare intrinsics as function items",
),
rustc_attr!(
rustc_no_mir_inline, Normal, template!(Word), WarnFollowing, EncodeCrossCrate::Yes,
"`#[rustc_no_mir_inline]` prevents the MIR inliner from inlining a function while not affecting codegen"
),
rustc_attr!(
rustc_force_inline, Normal, template!(Word, NameValueStr: "reason"), WarnFollowing, EncodeCrossCrate::Yes,
"`#[rustc_force_inline]` forces a free function to be inlined"
),
// ==========================================================================
// Internal attributes, Testing:
// ==========================================================================
rustc_attr!(TEST, rustc_effective_visibility, Normal, template!(Word), WarnFollowing, EncodeCrossCrate::Yes),
rustc_attr!(
TEST, rustc_outlives, Normal, template!(Word),
WarnFollowing, EncodeCrossCrate::No
),
rustc_attr!(
TEST, rustc_capture_analysis, Normal, template!(Word),
WarnFollowing, EncodeCrossCrate::No
),
rustc_attr!(
TEST, rustc_insignificant_dtor, Normal, template!(Word),
WarnFollowing, EncodeCrossCrate::Yes
),
rustc_attr!(
TEST, rustc_no_implicit_bounds, CrateLevel, template!(Word),
WarnFollowing, EncodeCrossCrate::No
),
rustc_attr!(
TEST, rustc_strict_coherence, Normal, template!(Word),
WarnFollowing, EncodeCrossCrate::Yes
),
rustc_attr!(
TEST, rustc_variance, Normal, template!(Word),
WarnFollowing, EncodeCrossCrate::No
),
rustc_attr!(
TEST, rustc_variance_of_opaques, Normal, template!(Word),
WarnFollowing, EncodeCrossCrate::No
),
rustc_attr!(
TEST, rustc_hidden_type_of_opaques, Normal, template!(Word),
WarnFollowing, EncodeCrossCrate::No
),
rustc_attr!(
TEST, rustc_layout, Normal, template!(List: "field1, field2, ..."),
WarnFollowing, EncodeCrossCrate::Yes
),
rustc_attr!(
TEST, rustc_abi, Normal, template!(List: "field1, field2, ..."),
WarnFollowing, EncodeCrossCrate::No
),
rustc_attr!(
TEST, rustc_regions, Normal, template!(Word),
WarnFollowing, EncodeCrossCrate::No
),
rustc_attr!(
TEST, rustc_delayed_bug_from_inside_query, Normal,
template!(Word),
WarnFollowing, EncodeCrossCrate::No
),
rustc_attr!(
TEST, rustc_dump_user_args, Normal, template!(Word),
WarnFollowing, EncodeCrossCrate::No
),
rustc_attr!(
TEST, rustc_evaluate_where_clauses, Normal, template!(Word), WarnFollowing,
EncodeCrossCrate::Yes
),
rustc_attr!(
TEST, rustc_if_this_changed, Normal, template!(Word, List: "DepNode"), DuplicatesOk,
EncodeCrossCrate::No
),
rustc_attr!(
TEST, rustc_then_this_would_need, Normal, template!(List: "DepNode"), DuplicatesOk,
EncodeCrossCrate::No
),
rustc_attr!(
TEST, rustc_clean, Normal,
template!(List: r#"cfg = "...", /*opt*/ label = "...", /*opt*/ except = "...""#),
DuplicatesOk, EncodeCrossCrate::No
),
rustc_attr!(
TEST, rustc_partition_reused, Normal,
template!(List: r#"cfg = "...", module = "...""#), DuplicatesOk, EncodeCrossCrate::No
),
rustc_attr!(
TEST, rustc_partition_codegened, Normal,
template!(List: r#"cfg = "...", module = "...""#), DuplicatesOk, EncodeCrossCrate::No
),
rustc_attr!(
TEST, rustc_expected_cgu_reuse, Normal,
template!(List: r#"cfg = "...", module = "...", kind = "...""#), DuplicatesOk,
EncodeCrossCrate::No
),
rustc_attr!(
TEST, rustc_symbol_name, Normal, template!(Word),
WarnFollowing, EncodeCrossCrate::No
),
rustc_attr!(
TEST, rustc_def_path, Normal, template!(Word),
WarnFollowing, EncodeCrossCrate::No
),
rustc_attr!(
TEST, rustc_mir, Normal, template!(List: "arg1, arg2, ..."),
DuplicatesOk, EncodeCrossCrate::Yes
),
gated!(
custom_mir, Normal, template!(List: r#"dialect = "...", phase = "...""#),
ErrorFollowing, EncodeCrossCrate::No,
"the `#[custom_mir]` attribute is just used for the Rust test suite",
),
rustc_attr!(
TEST, rustc_dump_item_bounds, Normal, template!(Word),
WarnFollowing, EncodeCrossCrate::No
),
rustc_attr!(
TEST, rustc_dump_predicates, Normal, template!(Word),
WarnFollowing, EncodeCrossCrate::No
),
rustc_attr!(
TEST, rustc_dump_def_parents, Normal, template!(Word),
WarnFollowing, EncodeCrossCrate::No
),
rustc_attr!(
TEST, rustc_object_lifetime_default, Normal, template!(Word),
WarnFollowing, EncodeCrossCrate::No
),
rustc_attr!(
TEST, rustc_dump_vtable, Normal, template!(Word),
WarnFollowing, EncodeCrossCrate::No
),
rustc_attr!(
TEST, rustc_dummy, Normal, template!(Word /* doesn't matter*/),
DuplicatesOk, EncodeCrossCrate::No
),
gated!(
omit_gdb_pretty_printer_section, Normal, template!(Word),
WarnFollowing, EncodeCrossCrate::No,
"the `#[omit_gdb_pretty_printer_section]` attribute is just used for the Rust test suite",
),
rustc_attr!(
TEST, pattern_complexity_limit, CrateLevel, template!(NameValueStr: "N"),
ErrorFollowing, EncodeCrossCrate::No,
),
];
pub fn is_builtin_attr_name(name: Symbol) -> bool {
BUILTIN_ATTRIBUTE_MAP.get(&name).is_some()
}
/// Whether this builtin attribute is encoded cross crate.
/// This means it can be used cross crate.
pub fn encode_cross_crate(name: Symbol) -> bool {
if let Some(attr) = BUILTIN_ATTRIBUTE_MAP.get(&name) {
attr.encode_cross_crate == EncodeCrossCrate::Yes
} else {
true
}
}
pub fn is_valid_for_get_attr(name: Symbol) -> bool {
BUILTIN_ATTRIBUTE_MAP.get(&name).is_some_and(|attr| match attr.duplicates {
WarnFollowing | ErrorFollowing | ErrorPreceding | FutureWarnFollowing
| FutureWarnPreceding => true,
DuplicatesOk | WarnFollowingWordOnly => false,
})
}
pub static BUILTIN_ATTRIBUTE_MAP: LazyLock<FxHashMap<Symbol, &BuiltinAttribute>> =
LazyLock::new(|| {
let mut map = FxHashMap::default();
for attr in BUILTIN_ATTRIBUTES.iter() {
if map.insert(attr.name, attr).is_some() {
panic!("duplicate builtin attribute `{}`", attr.name);
}
}
map
});
pub fn is_stable_diagnostic_attribute(sym: Symbol, _features: &Features) -> bool {
match sym {
sym::on_unimplemented | sym::do_not_recommend => true,
_ => false,
}
}
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